Abstract:
In a locking system particularly suitable for a motor vehicle for use with unidirectional electrical motors, there is interposed between motors of the system and locking elements individually driven by said motors, a driving mechanism including a driven member coupled with each of the locking elements, an eccentric drive element engaging said driven member to move the locking elements between locking and unlocking positions, and elastic means interposed between the driven member and the eccentric drive element to permit the motors to continue to rotate the eccentric drive element when movement of any one of the locking elements is obstructed.

Description:
The present invention relates generally to locking systems particularly suitable for use in motor vehicles and more particularly to a driving mechanism for such locking systems operable to control locking of doors, tops and hoods of such motor vehicles. 
     A door locking system for motor vehicles is known from U.S. Pat. No. 3,243,216 wherein the system can be locked or unlocked in a conventional manner by means of a key or by an operating rod which ends in an actuating button at the vehicle door. This driving mechanism has a unidirectional electrical geared motor which also acts upon the operating rod by means of an eccentric drive device. The eccentric drive includes a driven member which is slidably supported on the operating rod and which is pressed by a spring against a fixed stop of the operating rod. An eccentric element of the eccentric drive mechanism moves the driven member and consequently the operating rod between a first position wherein the lock is in the locked condition and a second position in which the lock is unlocked, and vice versa. 
     The motor is connected by a control circuit to always effect rotation of the eccentric element through one half of a rotation. Since the driven member is supported for the operating rod to be slidable against the force of the spring, the door lock can be manually unlocked even if the eccentric drive is blocked which may, for example, occur due to failure of the system. 
     The geared motor of the known driving mechanism is only disconnected at the final position. However, this final position is not reached if the locking mechanism is blocked, for example by icing or due to failure. This may lead to destruction or damage of the drive motor or of the eccentric drive mechanism of this known device. 
     The present invention is directed toward improving driving mechanisms for locking arrangements of motor vehicles in such a manner that damage will not occur even during obstruction of the locking mechanism of the system. 
     SUMMARY OF THE INVENTION 
     Briefly, the present invention may be described as a locking system particularly suitable for a motor vehicle for use with a unidirectional electric motor comprising lock means movable between a locking and an unlocking position, a driven member coupled with said lock means, an eccentric drive element for engaging said driven member to move said lock means between said locking and unlocking position, motor means for rotatively driving said eccentric element, control circuit means including switch means responsive to the position of said lock means for controlling operation of said motor means, and elastic means interposed between said driven member and said eccentric drive element to permit said motor means to continue to rotatively drive said eccentric drive element when movement of said lock means is obstructed. 
     Thus, improvements are achieved according to the present invention in that a compensating arrangement is installed in the force transmission path between the eccentric element and the driven member, which driven member is usually slidably maintained within a guide frame. The compensating arrangement is effected in both sliding directions of the driven member and the motor means and/or the compensating arrangement is dimensioned in such a way that the motor means is capable of rotating the eccentric element even if the driven member or the lock means become obstructed. 
     As a result, the motor means can always rotate the eccentric element into a final position thereof even if the driven member is obstructed. In this final position, the motor means will be disconnected by the control circuit means. 
     In accordance with a more specific aspect of the invention, the driven member may be formed as a frame having two elastic compensating elements which are arranged opposite each other and spaced apart in the sliding direction of the driven member with the eccentric element engaging between these two compensating elements. The compensating elements may be formed as blocks of rubber or similar elastic material. However, in a preferred embodiment of the invention, compression springs which are supported at the driven member frame are provided. If necessary, sliding members may also be provided which are slidably guided at the frame in its sliding direction in order to reduce damage due to wear. 
     The driving mechanism is particularly suitable for use in the central locking system of a motor vehicle especially when each of the driving mechanisms is provided with a control switch by means of which the remaining driving mechanisms of the central locking system in the unlocking position of one of the driving mechanisms can also be controlled into the unlocking position. In this manner, if one of the locking devices of the motor vehicle locks is obstructed, it will be prevented that this lock will remain unlocked without being noticed when the central locking system is locked while the remaining locks are correctly locked. The control switch of the driving mechanism of that lock which remains unlocked in this case steers all remaining locks into the unlocked position which usually will not remain unnoticed by the operator of the vehicle. 
     As a result, an indication of a malfunction in the locking system will be provided if any one of the locking elements remains unlocked. 
     The compensating arrangement permits manual adjustment of the drive member of the eccentric drive mechanism independently from the position of the eccentric element and consequently the motor vehicle lock may also be unlocked or locked manually. The driving mechanism may be expanded in a simple manner to include a theft protection function will prevent manual unlocking of the lock. For this purpose, a second drive member may be coupled with the eccentric element which can be moved by the eccentric element transversely to its rotational axis along a guide device which is attached to the motor with this driven member mechanically blocking in a first position the unlocking mechanism which is to be manually actuated against manual activation and releases it in a second position. Advantageously, the final positions of the eccentric element are always rotated further by 90° against the angular positions which move the driven element into the first or the second position. In this way, the eccentric element can be held by means of a limit switch, when the theft protection is turned on, in an intermediate position in which driven members take up a dead center position of the sliding movement. 
     The various features of novelty which characterize the invention are pointed out with particularity in the claims annexed to and forming a part of this disclosure. For a better understanding of the invention, its operating advantages and specific objects attained by its use, reference should be had to the accompanying drawings and descriptive matter in which there is illustrated and described a preferred embodiment of the invention. 
    
    
     DESCRIPTION OF THE DRAWINGS 
     In the drawings: 
     FIG. 1 is a schematic sectional view showing a driving mechanism for the lock system of a motor vehicle door or other like elements of the vehicle, structured in accordance with the present invention; and 
     FIG. 2 is a circuit diagram for a central locking system for the motor vehicle which is structured utilizing the driving mechanism depicted in FIG. 1. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Referring now to the drawings, the locking system of the present invention is provided with a driving mechanism in accordance with FIG. 1 which is formed with an essentially closed housing 1 having therein a frame 3 supported and guided for sliding movement. The frame 3 is rigidly connected with a rod 5 which projects beyond the housing 1. The rod 5 is connected to a locking element (not shown) of one of several locks of a motor vehicle which is to be controlled by operation of the invention, as will be more fully explained hereinafter. The locking system of the locking element may be manually locked or unlocked by means of a key or by manual actuation of a button such as that which may be provided on the door of a vehicle. A locking element of the locking system is unlocked when the rod 5 and the frame 3 are in the position shown in FIG. 1. When the rod 5 and the frame 3 are moved into a final position toward the bottom as viewed in FIG. 1, the locking element is brought to the locked position. 
     An eccentric cam 7 arranged within the housing 1 is mounted to be unidirectionally rotated in a direction indicated by the arrow 11. An electrical geared motor 9 which is flanged to the housing 1 is provided for driving the eccentric cam 7. 
     The eccentric cam 7 operates to engage a pair of sliding or movable plates 13 and 15 which are supported on the frame 3 in order to drive the frame 3 and the rod 5 between the unlocking position and the locking position of a respective locking element. The sliding plates 13, 15 are arranged on both sides of the eccentric cam 7 taken in the sliding direction of the frame 3 and they are themselves mounted so as to be movable relative to the frame 3 in the sliding direction of the frame 3. 
     The plates 13 and 15 are made slidably movable relative to the frame 3 by means of compression springs 17 and 19, respectively, interposed between the plates 13, 15 and the frame 3. The lengths of the paths of movement of the sliding plates 13, 15 are dimensioned in such a manner that the eccentric cam 7 can rotate against the pressure of the compression springs 17 and 19 past the sliding plates 13 or 15 even when the frame 3 is in the final position which has been reached always when the other sliding plate is acted upon. In addition, the force of the compression springs 17 and 19 as well as the driving power of the geared motor 9 are dimensioned in such a way that the eccentric cam 7 during normal operation can move the frame and the locking system connected therewith, while if the frame 3 or the locking system of the lock is obstructed, the eccentric cam 7 can rotate over the hindering sliding plate. In its stoppage position, the eccentric cam 7 is always rotated further by 90° against the angular position which it occupies when reaching the final position of the frame 3. 
     A blocking element 21 is also movably supported in the sliding direction of the frame 3 at the housing 1, the element 21 being coupled by means of a guide rod 23 with the eccentric cam 7. The eccentric cam 7 moves the blocking element 21 in the same direction with the frame 3 wherein, however, the lift of the blocking element 21 is greater than the lift of the frame 3. The blocking element 21 and the frame 3 reach the dead center positions which are located at the top or the bottom in FIG. 1 at the same angular position of the eccentric cam 7. On the blocking element 21, a projection 25 is installed which engages behind the frame 3 on the side which is located in the unlocking direction of the frame 3. This projection locks the frame 3 against manual shifting in the bottom dead center position which corresponds to the locking position of the lock. 
     The geared motor can be stopped in the locking dead center position if a theft protection circuit (not shown) of the motor vehicle is activated. 
     The driving mechanism is controlled by means of two switches 29 and 31, with the switch 29 being operated in dependence on the position of the rod 5 or a part fixedly connected with this rod, and with the switch 31 being operated in dependence on the position of the eccentric cam 7 or a part which is firmly connected therewith. 
     FIG. 2 shows details of a control circuit of a central locking system of a motor vehicle which is constructed with the driving mechanism according to FIG. 1. The switches 29 and 31 and the geared motors 9 which belong to the same driving mechanism are identified with similar reference characters. The driving mechanisms identified with the reference characters a and b drive the locking elements in the front doors of the vehicle which can be locked or unlocked manually by means of a key as well as also by means of actuating buttons in the doors. The driving mechanisms identified by reference characters utilizing reference letters c and d may be connected to close the rear doors of the vehicle which may also be manually locked by means of actuating buttons. The driving mechanism identified with e locks the trunk of the vehicle. 
     The motors 9 are connected in parallel always with one connection, at the one pole of a vehicle battery 33 whose other connection is connected in parallel with all center contacts of the switches 29. The other connection of the motors 9 is connected with the movable contact of the respectively assigned switches 31. The switches 31 are constructed as reversing switches wherein always the respective contacts are connected parallel with each other. The switches 31 are operated, for example, by means of a cam 34 in such a manner that they are switched over when the respective final position of the eccentric cam 7 has been reached. The switches 29a and 29b are also constructed as reversing switches. Their fixed contacts are connected with the fixed contacts of the assigned switches 31a and 31b in such a way that during switching over of the switches 29a or 29b the electrical circuit of the motors which are joined in parallel by means of the switch 31a or 31b which is waiting in the always other final position. In FIG. 2, the switches 29a and 29b are shown in the unlocking position. The unlocking position of the eccentric cam 7 corresponds to the position of the switches 31a-31e which is shown. When the switch 29a or 29b is switched over, all the motors 9a-9e are connected until the other final position is reached in which the switches 31a-31e change over into the position shown at the top in FIG. 2. In this position the locks are locked. 
     The switches 29c and d are shown as on-off switches which are closed in the unlocking position. They ensure that if the assigned driving mechanism is blocked, all driving mechanisms of the central locking system are again unlocked, even if they were already locked and this will give an indication of a malfunction. 
     In addition to the switches 29a-29e, a switch may be provided which is connected in parallel and which is actuated depending on acceleration and which unlocks during an accident any door which may be locked. 
     The switch 29c is constructed as a reversing switch actuated by means of a key--like switches 29a and 29b resp.,--except that this switch includes an electrically functionless switch position (indicated by dotted switch position). This functionless switch position is necessary to allow obstruction of the electromotively operated gear, if only the trunck remains locked and the doors are to be unlocked, when the car is in the repair shop, for example. 
     The switches 27, 29a-29e and 31a-31e may also be constructed as inexpensive sliding contacts. 
     While a specific embodiment of the invention has been shown and described in detail to illustrate the application of the inventive principles, it will be understood that the invention may be embodied otherwise without departing from such principles.