Lock system for motor vehicles

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.

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.degree. 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 
.

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.degree. 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.