Abstract:
An assembly comprising a latch mechanism operably connected to a controller, the mechanism having first and second operating modes with each mode having alternate states, the controller being programmed such that said second operating modes is not capable of use.

Description:
[0001]    This application is a continuation-in-part of U.S. Nonprovisional patent application Ser. No. 09/674,870, filed on Nov. 6, 2000, which claims priority to PCT applications PCT /GB99/01411, filed May 6, 1999, which itself claims priority to British application GB9809640.7, filed May 6,1998. 
     
    
     
       BACKGROUND OF THE INVENTION  
         [0002]    The present invention relates to latch assemblies for doors of vehicles and to a method of operating such an assembly.  
           [0003]    It is known to provide latch mechanisms on doors of vehicles to allow opening and closing of the door. Such latch mechanisms have various modes of operation, e.g.:  
           [0004]    a) Lock mode, wherein operation of an outside door handle does not open the latch mechanism;  
           [0005]    b) Superlocked mode, when in operation of an outside or an inside release lever does not operate the latch mechanism;  
           [0006]    c) Child safety mode, wherein operation of an inside release lever does not open the latch mechanism, whether or not the latch mechanism is locked; and  
           [0007]    d) Release mode, wherein the latch mechanism is released via means other than 20 operation of the inside or outside release levers.  
           [0008]    Each mode has alternate states, e.g., locked/unlocked, superlocked/not superlocked, child safety on/off and release/not released.  
           [0009]    Typically, each mode requires an individual mechanism to effect the alternative states, with operation of each mechanism being effected either manually or with an individual power actuator.  
           [0010]    In the case of a latch mechanism operated entirely by power actuators, such as DC motors, it is also necessary to be able to open a locked door which has the child safety feature on in an emergency situation when actuation of the power actuators is not possible, such as when the keys to the vehicle are not available.  
         SUMMARY OF THE INVENTION  
         [0011]    According to an aspect of the present invention there is provided an assembly comprising a latch mechanism operably connected to a controller, the mechanism having first and second operating modes with each mode having alternate states, the controller being programmed such that said second operating mode is not capable of use.  
           [0012]    A second aspect of the present invention provides a method of controlling a latch having first and second operating modes with each mode having alternate states, the method comprising the step of controlling the latch such that the second operating mode is not capable of use. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0013]    The various features and advantages of this invention will become apparent to those skilled in the art from the following detailed description of the currently preferred embodiment. The drawings that accompany the detailed description can be briefly described as follows:  
         [0014]    [0014]FIG. 1 is a latch mechanism forming part of a latch assembly according to an embodiment of the present invention in a super-locked condition.  
         [0015]    [0015]FIG. 1A is an enlarged view of part of FIG. 1.  
         [0016]    [0016]FIG. 1B is a schematic view in the direction of arrow A of FIG. 1.  
         [0017]    [0017]FIG. 2 is the latch mechanism of FIG. 1 in a locked position with child safety on.  
         [0018]    [0018]FIG. 3 is the latch mechanism of FIG. 1 in an unlocked condition with the child safety on.  
         [0019]    [0019]FIG. 4 is the latch mechanism of FIG. 1 in a locked condition with the child safety off.  
         [0020]    [0020]FIG. 5 is the latch mechanism of FIG. 1 in an unlocked position with the child safety off.  
         [0021]    [0021]FIG. 6 is a latch mechanism of FIG. 1 in a release position.  
         [0022]    [0022]FIG. 7 is a schematic plan view of a vehicle incorporating a latch assembly according to an embodiment of the present invention.  
         [0023]    [0023]FIG. 8 is a schematic plan view of a vehicle incorporating a latch assembly according to another embodiment of the present invention. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT  
       [0024]    With reference to FIGS.  1  to  6  there is a latch mechanism  10  including a body  11  which supports various components of the latch mechanism  10  as indicated below.  
         [0025]    Latch mechanism  10  further includes a claw  12  pivotally mounted about axis  13  on the body  11 . Claw  12  acts to secure an associated door (not shown) in a closed position via a striker pin  14  attached to the door aperture. Rotation of the claw  12  in an anticlockwise direction about axis  13  when viewing FIG. 1 allows release of the striker pin  14 , thus enabling opening of the associated door.  
         [0026]    The claw  12  is held in a closed position by a pawl  15 , only part of which is shown in dotted profile in FIG. 1 for clarity. Pawl  15  is pivotally mounted on body  11  and can rotate about axis  16 . Claw  12  can be held in a first safety position (not shown) when pawl  15  engages first safety abutment  17 .  
         [0027]    Pawl lifter  20  is generally flat and lies in a plane parallel to pawl  15 , to which it is rotationally secured. When viewing FIG. 1 pawl  15  is obscured by pawl lifter  20 . Clearly, pawl lifter  20  also rotates about axis  16 .  
         [0028]    Inside lock link  21  and outside lock link  22  are mounted for movement with the pawl, in this case they are each individually pivoted about respective axes  21   a  and  22   a  on pawl lifter  20 . In this case inside lock link  21  and outside lock link  22  are identical and each have respective cam followers  21   b  and  22   b  and release abutments  21   c  and  22   c.  Inside lock link  21  and outside lock link  22  are each biased in a clockwise direction when viewing FIG. 1 such that the respective cam followers  21   b  and  22   b  contact cam  30 .  
         [0029]    Cam  30  is capable of rotating independently from pawl lifter  20  about axis  16 . Cam  30  has three lobes  31 ,  32 , and  33  and two levers  34  and  35  shown diagrammatically for clarity. Lobes  31 ,  32 ,  33  and levers  34  and  35  are all rotationally fast with cam  30 .  
         [0030]    Preferably cam  30  can at least be rotated to the various positions as described below by a power actuator (not shown) such as a DC motor or preferably a stepper motor.  
         [0031]    Outside release lever  40  is pivotally mounted about axis  41 . Inside release lever  43   5  (shown diagrammatically in FIG. 1 b ) is pivotally mounted about axis  44 .  
         [0032]    Operation of a door latch mechanism is as follows.  
         [0033]    [0033]FIG. 1 shows the door latch mechanism in a super lock condition, that is to say operation of the outside release lever  40  or inside release lever  43  does not allow unlatching of the mechanism. In particular it can be seen that if outside release lever  40  were to be operated by being rotated in a clockwise direction about axis  41 , abutment  42  would pass release abutment  22   c  of outside lock link without contact (note that outside release lever  40  is in the same plane as outside lock link  22 ). Similarly inside release lever  43  when operated by being rotated in an anticlockwise direction about axis  44  when viewing FIG. 1 b,  would cause abutment  45  to pass release abutment  21   c  of inside lock link  21  (see especially FIG. 1).  
         [0034]    [0034]FIG. 2 shows the door latch mechanism  10  in a locked position with the child safety feature on. It will be noted that cam  30  has been rotated  30  degrees in an anticlockwise direction when compared to FIG. 1. However, the inside lock link  21  and outside lock link  22  are in the same position when compared with FIG. 1 since neither of the cam followers  21   b  or  22   b  have, at this stage, ridden up any of the lobes  31 ,  32  or  33  or the cam  30 . However, lever  34  has been rotated to a position whereby operation of the inside release lever  43  in an anticlockwise direction when viewing FIG. 1 b  would cause abutment  46  to contact lever  34  and rotate cam  30  to the position shown in FIG. 3. Note this initial operation of inside release lever  43  does not unlatch the mechanism but only operates to unlock the door (see below). This method of being able to override and open a locked door which has the child safety on is especially important in an emergency situation whereby a passer-by can effect access to the inside door handle (e.g., by breaking the door window glass), operate the inside door handle to unlock the door, then operate the outside door handle to open the door and then remove the child from the car.  
         [0035]    [0035]FIG. 3 shows the door latch mechanism  10  in an unlocked condition with the child safety feature on. In this case the cam  30  has been rotated sufficiently (either by operating the inside release lever when the cam was in the position shown in FIG. 2 or by independent rotation of the cam directly e.g., by a power actuator) such that cam follower  22   b  has ridden up cam lobe  32  resulting in anticlockwise rotation of outside lock link  22 . Thus when outside release lever  40  is operated, abutment  42  contact release abutment  22   c  causing the pawl lifter  20  as a whole to rotate anticlockwise when viewing FIG. 3 and releasing the pawl  15  and allowing the claw  12  to open. Stop  22   d  limits the anticlockwise rotation of outside lock link  22 . Upon release of the outside release lever  40  the pawl lifter  20  is biased back to the position as shown in FIG. 3 by a spring (not shown). It should also be noted that the inside lock link  21  is in the same position as that shown in FIG. 1, thus operation of the inside release lever  43  does not allow opening of the door.  
         [0036]    [0036]FIG. 4 shows the door latch mechanism  10  in a locked condition with the child safety feature off. It should be noted that the cam  30  has been rotated 90 degrees in an anticlockwise direction when compared with FIG. 1. This results in cam follower  22   b  being situated between lobes  32  and  33  thus ensuring that operation of outside release lever  40  does not release the latch mechanism. Furthermore, the rotation of the cam  30  has caused cam follower  21   b  to ride up cam lobe  31  causing inside lock link  21  to rotate anticlockwise about axis  21   a.  Thus abutment  21   c  of inside lock link  21  is contacted by abutment  45  of inside release lever  43  when it is operated. This causes anticlockwise rotation of the pawl lifter  20  about axis  16  resulting in unlatching of the door mechanism and allowing the door to be subsequently opened. Stop  21   d  limits the anticlockwise rotation of inside lock link  21 . It should be noted that the operation of the inside release lever  43  also causes abutment  46  to contact lever  35  causing rotation of cam  30  to the position shown in FIG. 5. This prevents a vehicle occupant inadvertently locking himself out of the vehicle since opening of the door from the inside automatically unlocks the door, allowing subsequent opening from the outside.  
         [0037]    [0037]FIG. 5 shows the door latch mechanism  10  in an unlocked position with the child safety feature off. It can be seen that the cam has been rotated (either by operating the inside release lever when the cam was in the position shown in FIG. 4 or by independent rotation of the cam directly e.g., by a power actuator) such that abutment  22   b  now rests on lobe  33  allowing operation of the outside release lever  40  to unlatch the latch mechanism as described above. Furthermore abutment  21   b  remains in contact with lobe  31  thus ensuring that operation of the inside release lever also unlatches the door mechanism.  
         [0038]    [0038]FIG. 6 shows the door latch mechanism  10  in a released position. This is achieved by rotation of cam  30  in an anticlockwise direction which allows contact between corresponding lost motion abutments (not shown) on the pawl lifter  20  and cam  30 . Such lost motion abutments allow the cam  30  to rotate the pawl lifter  20  to release the door latch mechanism independently of the operation of the outside release lever  40  or the inside release lever  43 .  
         [0039]    Note that only a single cam is required to effect the various modes of operation.  
         [0040]    In further embodiments the inside and outside lock links can be mounted directly on the pawl.  
         [0041]    Referring to FIGS. 7 and 8 latch mechanisms  10 A,  10 B,  10 C and  10 D are shown fitted to doors  114 A,  114 B,  114 C and  114 D, respectively, of a vehicle  100 . Latch mechanism  10 A,  10 B,  10 C and  10 D are all constructed like latch mechanism  10 .  10 A, however, is a mirror image of  10 B because they are on opposite facing doors with opposing facing inside and outside release levers.  10 C and  10 D are also mirror images of each other. Latch mechanisms  10 A,  10 B,  10 C and  10 D may be controlled either by an integral controller (FIG. 8, 110 b ) or an external controller (FIG. 7,110 a ) so that one or more of the aforementioned modes of operation are bypassed. This is achieved by the controller  110   a ,  110   b  signalling the power actuator  112  to drive the cam  30  so that one or more lobes  31 ,  32  or  33  pass straight past lock links  21  and  22 , meaning that this mode never appears to be available to a vehicle user. Power actuator  112  is preferably a stepper motor that may be controlled by controller  110   a  or  110   b  to rotate past the particular mode.  
         [0042]    For example, it may be undesirable to have a child safety mode for front doors  114 A and  114 B but desirable to have a child safety mode for rear doors  114 C and  114 D. Rather than use a different latch mechanism for  114 A and  114 C or  114 B and  114 D, the same or substantially the same latch mechanism may be employed by programming controllers  110   a  or  110   b  to disable the child safety mode for front door latch mechanisms  10 A and  110 B but not to disable this mode for latch mechanisms  10 C and  10 D of rear doors  114 C and  114 D. Thus, controllers  110   a  or  110   b  would be programmed to control power actuators  112  to dial the cams of  10 A and  10 B to avoid child safety mode.  
         [0043]    This feature may be used to enable a latch mechanism having a child safety mode to be fitted on the front door of a vehicle where child safety is not required, and/or to enable latches having a superlocking mode to be fitted to vehicles for sale in territories (e.g. the USA) which traditionally do not have vehicles supplied with a superlocking mode.  
         [0044]    It will be appreciated that the number of operating modes available to end users for a particular latch mechanism may be set prior to fitting the latch mechanism to a vehicle, or after the vehicle is assembled. In certain variants, the latch mechanism may be re-programmable after fitting either by service personnel or vehicle users.  
         [0045]    It will further be appreciated that by being able to manufacture a single latch mechanism which may be used in a variety of differing vehicle doors and sale territories, significant cost savings in the manufacture and supply of the mechanism may be achieved.  
         [0046]    The aforementioned description is exemplary rather that limiting. Many modifications and variations of the present invention are possible in light of the above teachings. The preferred embodiments of this invention have been disclosed. However, one of ordinary skill in the art would recognize that certain modifications would come within the scope of this invention. Hence, within the scope of the appended claims, the invention may be practiced otherwise than as specifically described. For this reason the following claims should be studied to determine the true scope and content of this invention.