With a device for connecting a motor vehicle window pane, connected to a pane socket, to a window lifter which has a follower connected to the guide and transport element of the window lifter, the follower and the pane socket are connected together through at least two spatially separated positive locking elements which engage in succession in each other during assembly and with keyed connection in different directions. First positive locking elements are thereby connected with each other in the assembly direction of the window pane and second positive locking elements are aligned opposite relative to each other in a plane running substantially at right angles to the assembly direction of the window pane and are brought into engagement with each other through a swivel movement of the window pane after connection of the first positive locking elements. Third positive locking elements serve for the additional mechanical securement of the connection of the follower and pane socket and engage with each other when the window pane is partly or fully opened.

CROSS-REFERENCE 
     This application claims priority of German Application No. 198 60 745.8 filed Dec. 23, 1998, a copy of which is Attachment A hereto, the disclosure of which is incorporated fully herein by reference. 
     FIELD OF THE INVENTION 
     The invention relates to a device for connecting a motor vehicle window pane to a window lifter. 
     BACKGROUND OF THE INVENTION 
     From JP 6 135228 a device is known for connecting a motor vehicle window pane to a window lifter wherein the lower edge of the window pane is connected to two pane sockets which each have two spaced webs with a wedge-shaped tip. Two clip-like followers connected to a window lifter device have an inclined lead-in area and an undercut hollow cavity for holding with keyed engagement the wedge-shaped tips of the pane sockets connected to the window pane. As a result of the only slight keyed engagement between the wedge-shaped tips and the undercut hollow cavity, in order to secure the connection between the pane sockets and the followers a bore is provided penetrating through the arms of each follower to house a screw connection with which the arms of the followers are tensioned so that the position of the wedge-shaped tips of the pane sockets in the followers is secured. 
     With this known device for connecting a motor vehicle window pane to the followers of a window lifter it is necessary to align the positive locking elements of the pane sockets and the follower precisely relative to each other and in addition to tension the followers with force-locking engagement to secure the connection between the pane sockets and followers, which in turn necessitates visual contact with the connecting means and access to the followers during assembly. Connecting the window pane to the window lifter therefore requires an open door shaft and a longer assembly time which leads to considerable costs during assembly. 
     From DE 44 23 440 A1 a device is known for connecting a motor vehicle window pane to the guide device of a window lifter where in the region of the lower edge of the window pane a cylindrical connecting element is connected to the window pane and the guide device has, perpendicular to the plane of the pane, spring-elastic retaining arms with an incline for guiding in the connecting element. Recesses provided in the spring-elastic retaining arms serve to hold the connecting element in the fastening state where the connection between the connecting element and recesses is produced by the connecting element snap-fitting into the recesses. 
     The positive-locking detent connection between the connecting element and the retaining arms does not require any additional tensioning of the retaining arms to secure the connection, and the guide-in phase at the upper ends of the retaining arms allows a rough pre-adjustment so that the connection between the window pane and the guide device of a window lifter can also be carried out without any visual contact. Blind fitting when fastening the window pane on the window lifter is thus possible and no open door shaft is required during assembly. 
     SUMMARY OF THE INVENTION 
     The object of the present invention is to provide a device for connecting a motor vehicle window pane, connected to a pane socket, to a window lifter of the type already mentioned which allows blind fitting, is characterized by high stability and high resistance moment across the plane of the pane and guarantees a secure connection between the window pane and window lifter even with tilting movements of the window pane. 
     The solution according to the invention allows a blind fitting when connecting the motor vehicle window pane to a window lifter, i.e. assembly is possible even in the absence of visual contact with the connecting means, for example in the case of a closed door shaft of a motor vehicle door. It ensures a high resistance moment across the plane of the pane through a large surface area connection of the window pane with the window lifter through the spatially separated positive locking elements and a secure connection, even in the event of tilting movements of the window pane, through the positive locking elements which can be connected together with keyed engagement in different directions. The device according to the invention is particularly suitable for frameless vehicle doors where the window pane is exposed as a result of the absence of side guides to additional tilting movements perpendicular to the plane of the pane. 
     Since according to a further feature of the invention the positive locking elements enter into engagement in succession when connecting the window pane to the window lifter, a simple and reliable assembly is guaranteed where the fitter can also control and monitor the individual assembly steps and thus the completion of the connection without any visual contact. 
     Preferably first positive locking elements are provided for bringing together and/or aligning the follower and the pane socket while second positive locking elements are provided for locking the connection between the follower and pane socket. Through the spatial separation and different function of the positive locking elements handling becomes easier during assembly and the combination of the different function parts of the positive locking elements, ensures a secure connection between the window pane and window lifter. 
     One advantageous development of the solution according to the invention is characterized in that the first positive locking elements can be connected together with keyed engagement in the assembly direction of the window pane and that the second positive locking elements are aligned oppositely to each other in a plane running substantially at right angles to the assembly direction of the window pane and can be brought into engagement after connection of the first positive locking elements through a swivel movement of the window pane. 
     This design of the solution according to the invention allows the fitter to insert the window pane, with the pane socket fixed thereon, into a door shaft of a motor vehicle door until keyed connection of the first positive locking elements, and then to produce a keyed connection of the second positive locking elements by swivelling the window pane around the first keyed connection. Instead of swivelling the window pane it is also possible to press on the pane socket and follower in the case of an opened door shaft. 
     Through the different alignment of the positive locking elements which engage in each other with keyed connection, on the one hand, in the assembly direction and, on the other, at right angles to the assembly direction, a secure connection is guaranteed between the window pane and window lifter even with different force action on the window pane. Thus this design is particularly suitable for frameless door systems and ensures an increased protection against theft since the window pane, even in the partly opened state, cannot be forcefully removed from the locking action with the window lifter. 
     An advantageous development of the solution according to the invention is characterized in that third positive locking elements are provided for the additional mechanical securement of the connection between the follower and pane socket and which engage with each other when the window pane is partly or completely opened. 
     The arrangement of an additional mechanical securement which is active particularly in the case of a partly or fully opened window pane prevents the window pane from tilting even in the event of extreme loads and also prevents forced release of the connection between window pane and window lifter so as to ensure further improved protection against theft. 
     With a method for connecting a motor vehicle window pane to a window lifter which is mounted in a door shaft of the vehicle door defined by an outer door panel and an inner door panel, a door module or an inner door trim and which has at least one follower connected to the guide and transport means of the window lifter and holding the window pane, the window pane is connected in the region of its lower edge to a pane socket and is inserted together with the pane socket into the door shaft where it is pushed into the door shaft until the positive locking elements which are mounted on both the pane socket and on the follower stand opposite one another. The follower and the pane socket are brought into a stop position with keyed connection of one part of the positive locking elements and then oppositely aligned further positive locking elements are brought into engagement with each other by swivelling the window pane. 
     These method steps for connecting a vehicle window pane to a window lifter ensure simple fitting and allow blind fitting without visual contact of the connecting elements, ensure a fixed connection between the vehicle window pane and window lifter even with great forces acting on the plane of the pane and enable the control and monitoring of the secure connection through successive assembly steps of which the first assembly step has to be completed before the second assembly step is possible and the completion of the second assembly step is indicated by a discernible or audible connection of the additional positive locking elements. 
     A further advantageous development of the method according to the invention is characterized in that the window pane is pushed so far into the door shaft until corresponding first positive locking elements on the pane socket and on the follower engage in each other, and that the window pane is swivelled about the keyed connection of the first positive locking elements until the oppositely aligned further positive locking elements engage with each other and lock with each other. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The idea on which the invention is based will now be explained in further detail with reference to the embodiments shown in the drawings in which: 
     FIG. 1 is a diagrammatic perspective view of a connecting device with two spatially separated positive locking elements which are aligned in different connecting directions relative to each other; 
     FIGS. 2 to 4 show a diagrammatic view of the individual movement phases when making a keyed connection between a follower and a pane socket; 
     FIG. 5 shows a diagrammatic perspective view of a further connecting device with additional mechanical securement; and 
     FIG. 6 is a side view of the connecting device according to FIG. 5 in the assembled state. 
    
    
     DETAILED DESCRIPTION 
     FIG. 1 shows in perspective view a follower 2 and a pane socket 3 for connecting a motor vehicle window pane to a window lifter. A motor vehicle window pane (not shown) is inserted in the shaft 33 formed by two side arms of the pane socket 3 and a base surface, and where applicable, is connected by additional fastening means to the pane socket 3, for example, by sticking or by further positive-locking connecting means. The follower 2 consists in the illustrated embodiment of a basic follower body 2a and a coupling body 2b which are connected together in the longitudinal direction by a concave/convex connecting surface 29a, 29b. The basic follower body 2a is connected through a guide slit 24 to a window lifter guide rail and has a cable mounting 25 in which a window lifter cable is hung for moving the follower 2 and thus the window pane up and down. 
     The coupling body 2b of the follower 2, which is to be connected to the pane socket 3, has on its upper edge a trough 21 which corresponds to a hook 31 of the pane socket 3. The trough 21 and hook 31 form first positive locking elements to connect the follower 2 and pane socket 3. 
     As second positive locking elements, a detent nose 22 is provided on the coupling body 2 and a detent hook 32 is provided on the pane socket 3 in the region of the lower edge of the follower 2 and pane socket 3. In the embodiment illustrated in FIG. 1, the detent nose 22 is movable elastically perpendicular to the contact bearing faces 20, 30 of the follower 2 and pane socket 3 so that when bringing together the follower 2 and pane socket 3 so that their bearing faces 20, 30 adjoin one another, the bent end of the detent hook 32 deflects the detent nose 22 and when pressing together the pane socket 3 and follower 2 the detent nose 22 and detent hook 32 hook together with snap-fitting engagement. 
     FIGS. 2 to 4 show the individual movement phases when joining the pane socket 3 and follower 2 according to FIG. 1. 
     Before making the connection between the follower 2 and pane socket 3, the pane socket 3 is pushed with the shaft 33 onto the lower edge of the window pane 1 and is connected to same in a suitable way with keyed and/or force-locking connection, preferably by adhesive. The follower 2 is connected to the guide rails and to a transport device, for example the cable, of a window lifter and is mounted inside the door shaft on the motor vehicle door. 
     The window pane 1 is inserted with the pane socket 3 fixed thereon through the upper slit of the door shaft of the vehicle door and is pushed in the direction of arrow A in FIG. 2 into the door shaft. When inserting the window pane 1 and pane socket 3 into the door shaft, the contact bearing face 30 of the pane socket 3 slides along the upper edge 23 of the follower 2 or along the contact bearing face 20 until the hook 31 of the pane socket 3 slides into the trough 21 formed on the top side of the follower 2 and finally makes a positive locking connection with the trough 21 according to FIG. 3. 
     The keyed connection between the hook 31 of the pane socket 3 and the trough 21 of the follower 2 is thus designed so that the pane socket 3 can swivel about the turning point formed between the hook 31 and trough 21. By pressing the lower edge of the pane socket 3 in the direction of arrow C or preferably by swivelling the window pane 1 in the direction of the arrow B, according to FIG. 3, the detent hook 32 at the lower end of the pane socket 3 presses against the elastically movable detent nose 22 of the follower 2 so that the detent nose 22 is deflected. With further pressure on the pane socket 3 and tilting of the window pane 1 the projections of the detent nose 22 and of the detent hook 32 engage in each other with snap-fit connection. 
     FIG. 4 shows the keyed connection between the first and second positive locking elements 21, 31 and 22, 32 and thus the fixed connection between the pane socket 3 and follower 2. 
     FIG. 5 shows in a perspective view and FIG. 6 shows in a side view a follower 2 and a pane socket 3 which are connected together by several positive locking elements 21, 31; 35, 36, 41, 42; 28, 38 so that the follower 2 and the pane socket 3 are connected fixed together at their contact bearing faces 20, 30. The follower 2 and the pane socket 3 are system components of a displacement device with force-dependent adjustment of a motor vehicle window pane 1, which in the event of a pretensioning force provided by a spring 7 being exceeded, executes a swivel movement of the window pane 1 so that the window pane 1 in the closed state presses against a door seal. This system is particularly suitable for frameless door systems where the window pane 1 is not guided in side guide slits of a door frame but adjoins with sufficient tightness against the door seal. 
     The window pane 1 is connected fixed to the pane socket 3 through a socket shaft 33 of the pane socket and forms one unit with the pane socket 3 prior to its connection with the follower 2. 
     The follower 2 consists of a basic follower body 2a and a coupling body 2b which are connected together for sliding movement in the longitudinal direction through a concave/convex shaped connecting surface 29a, 29b. Between the angled upper edge of the coupling body 2 and the upper edge of the basic follower body 2a is a spring 7 which presses the upper edges of the coupling body 2b and basic follower body 2a apart with predetermined pretension force and pretensions the two elements against each other. 
     The basic follower body 2a is connected to the guide rail through a guide slit 24 and to the transport cable of a window lifter through a cable mounting 25. 
     Underneath the follower 2 is a recess 26 in which a detent plate 4 can be inserted with a spring-elastic yoke 43. As a result of the spring-elastic yoke 43, the detent teeth 41, 42 formed on the detent plate 4 are mounted resiliently perpendicular to the lower edge of the follower 2. The detent teeth 41, 42 correspond with the teeth 35, 36 on the underneath projection 34 of the pane socket 3. 
     While the detent plate 4 is inserted underneath the coupling body 2b, a security detent tooth 28 is formed underneath the basic follower body 2a to correspond with a security detent tooth socket 38 on the underneath projection 34 of the pane socket 3. The security detent tooth 28 and the security detent tooth socket 38 are formed asymmetric and have inclined insert guides which, as described below, connect the basic follower body 2a and the coupling body 2b together with adjustment during displacement of the window pane. 
     A first positive locking element in the form of a trough 21 is formed on the top side of the coupling body 2b, into which a hook 31 of the pane socket 3 engages in the manner described above in connection with the variation according to FIG. 1. 
     Before connecting the coupling body 2b of the follower 2 with the pane socket 3, the pane socket 3 is pushed with the shaft 33 onto the lower edge of a window pane 1 and connected thereto. The basic follower body 2a is connected to the guide rails and to a transport device, for example the transport cable, of a window lifter and is installed together with the window lifter in the door shaft of a motor vehicle door. 
     The window pane 1 is inserted with the pane socket fixed thereon through the upper slit of the door shaft of the motor vehicle door and pushed into the door shaft. When inserting the window pane 1 and the pane socket 3 into the door shaft, the contact bearing face 30 of the pane socket 3 slides along the upper edge 23 of the coupling body 2b until the hook 31 of the pane socket 3 slides into the trough 21 formed on the top side of the follower 2, and finally produces a keyed connection with the trough 21 in which the pane socket 3 can swivel about the rotary point formed between the hook 31 and trough 21. 
     By pressing on the lower edge of the pane socket 3 or--in the case of blind fitting--by swivelling the window pane 1 about the rotary point formed between the trough 21 and hook 31, the detent sockets 35, 36 and 38 slide over the resiliently pliable detent teeth 41, 42 of the detent plate 4 until the security detent socket 38 snaps over the security detent tooth 28 on the surface underneath the basic follower body 2a through the adequate elasticity of the underneath projection 34 of the pane socket 3, and the detent teeth 41, 42 and 28 produce a keyed connection with the detent sockets 35, 36 and 38. 
     The separation of the follower 2 into a coupling body 2b connected to the pane socket 3 and a basic follower body 2a connected to the window lifter enables the window pane 1 to swivel on reaching an upper end position of the window lifter corresponding to the closing position of the window pane 1. 
     If in this position further displacement force is exerted through the transport cable onto the basic follower body 2a which is connected to the transport cable of the window lifter by the cable socket 25, then the upper edges of the coupling body 2b and the basic follower body 2a, which are spaced from each other through the spring force of the spring 7, are moved up towards each other against the pretensioning force of the spring 7 so that the convex guide face of the coupling body 2b slides along on the concave guide face of the follower 2a and thus the coupling body 2b executes a swivel movement about a rotary point lying outside of the follower 2 and pane socket 3 and the window pane 1 is swivelled against the door seal. 
     In the event of interaction between the basic follower body 2a and the coupling body 2b, the security detent tooth 28 and the security detent tooth socket 38 execute a double function. Apart from the additional mechanical securement described above, manufacturing tolerances of the individual components of the adjustment device are compensated since the security detent tooth 28 has a self-locking incline which includes an angle of, for example, 7 degrees relative to the vertical and the security detent tooth socket 38 has lead-in incline whose angle corresponds to the angle of the self-locking incline relative to the vertical. 
     When the displacement device reaches an upper end stop, the basic follower body 2a is moved against the pretensioning force of the spring 7 and the coupling body 2b swivels together with the pane socket 3. If the vehicle window pane is moved back from the end stop then the window pane is first swivelled into the movement position where the basic follower body 2a is moved in the opposite direction under the effect of the pretensioning force of the spring 7. The security detent tooth 28 thereby slides on the inclined surface and lead-in incline of the security detent tooth socket 38 into the security detent tooth socket 38. 
     Through the inclined surface of the security detent tooth 28 and the lead-in incline of the security detent tooth socket 38 during further movement, the basic follower body 2a and coupling body 2b as well as the pane socket, 3 are drawn together under the action of the pretensioning force of the spring 7 and any existing tolerances are compensated in this way.