Abstract:
A door release and engagement mechanism for a vehicle comprising a combined inside release and door pull handle and a latch operably connected thereto, wherein the mechanism is so constructed and arranged as to disable the operable connection when the door is ajar and/or unlatched so as to prevent the latch from being mis-set prior to subsequent re-closure of the door.

Description:
This application claims priority to Great Britain Patent Application (GB) 0122634.9 filed on 20 Sep. 2001. 
   BACKGROUND OF THE INVENTION 
   The present invention relates to a door release and engagement mechanism. More particularly, the present invention relates to a door release and engagement mechanism for a vehicle. 
   Typically, vehicle doors and in particular vehicle passenger doors are provided with a separate inside door engagement means such as a pull handle and inside release means such as an inside release handle. The use of two separate components for these functions inevitably increases the part count and door assembly time and hence the overall assembly cost. It also restricts the design freedom of the inside door trim upon which these components are typically mounted. 
   In vehicles fitted with a power unlatching system, pulling the inside release handle merely operates an electrical switch that sends an unlatching signal to the corresponding door latch. Nevertheless, it is desirable to include a mechanical connection between the release handle and the latch so that users may be able to exit the vehicle even when there is a loss of power to the latch. 
   SUMMARY OF THE INVENTION 
   The present invention seeks to overcome or at least mitigate the aforesaid problems. 
   One aspect of the present invention provides a door release and engagement mechanism for a vehicle comprising a combined inside release and door pull handle and a latch operably connected thereto, wherein the mechanism is so constructed and arranged as to disable the operable connection when the door is ajar and/or unlatched so as to prevent the latch from being mis-set prior to subsequent re-closure of the door. 
   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. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is a perspective view of a vehicle door incorporating a mechanism according to the present invention. 
       FIGS. 2A and 2B  are side and end elevational views respectively of a latch of the present invention in a latched state. 
       FIGS. 3A and 3B  are side and elevational views of the latch of  FIGS. 2A and 2B  in an unlatched state. 
       FIG. 4  is a schematic diagram of a vehicle having a door incorporating the present invention. 
       FIG. 5  is a flow chart illustrating the functioning of the invention. 
   

   DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
   Referring to  FIG. 1 , a door  10  comprises an interior trim panel  12  having an arm rest portion  14  provided thereon. Integral with the arm rest is a handle  16  that has the dual function of unlatching a latch  18  provided on the door  10  when the door is closed so as to enable the user to exit a vehicle (not shown) to which the door is fitted, and also to pull the door into a closed position when it is ajar (not closed). Generally, the simple combination of these function would not work since pulling on a single handle to close the door would prevent the corresponding latch from being latched at precisely the moment when latching should occur. This is because a pawl of the latch would be lifted clear from a latch bolt of the latch. 
   As described in further detail below, in this embodiment the handle  16  is operably connected to the latch by a mechanical connection and an electrical connection. In normal use, actuating the handle  16  closes a switch  52  and thereby sends an electrical signal to a power actuator  54  that causes the latch  18  to unlatch. Further, if the electrical power in the vehicle fails due to a flat battery, for example, a mechanical connection enables the latch  18  to be manually unlatched. 
   Considering first the mechanical connection,  FIGS. 2A and 2B  illustrate the latch  18  in a latched condition and in particular those parts constituting the mechanical connection between handle  16  and the latch  18 . The latch  18  comprises a latch bolt in the form of a claw  20  rotatably mounted about a pivot  22  to a latch chassis (not shown) and having a recess  24  which retains a striker  32  when the latch  18  is latched. The claw  20  further comprises a first abutment surface  26  for a first safety latched position and a second abutment surface  28  against which pawl  30  abuts to retain the claw  20  in a fully latched condition. Pawl  30  is resiliently biased into contact with claw  20 . The latch  18  further comprises an inside release lever  42  rotatably mounted to the latch chassis about a pivot  44 . 
   The lever  42  is connected to the handle  16  by a rod or cable (not shown) mounted to a pivot  46  such that actuating the handle  16  pulls the cable or rod in a direction X thereby causing the lever to pivot clockwise in a direction Y as shown in  FIG. 2B  and this is well known. The inside release lever  42  is in turn connected by a linkage (not shown) of known type to the pawl  30  such that when the lever  42  pivots in direction Y the pawl  30  lifts. 
   A block link  36  is mounted for slidable movement in a vertical plane only intermediate claw  20  and lever  42 . The link  36  comprises a substantially vertically arranged bar  37  having a substantially horizontally positioned claw abutment projection  38  formed integrally therewith at the upper end of the bar. A substantially horizontally arranged lever abutment projection  40  is formed integrally with the lower end of the bar  37 . When viewed along the longitudinal axis of the bar  37 , projections  38  and  40  are angled at substantially 90° to each other. As can be seen most clearly from  FIG. 2B , when the latch  18  is in a latched condition, the block link is arranged such that it does not impede rotation of lever  42 . 
   Turning now to  FIGS. 3A and 3B , the latch  18  is shown in an unlatched condition with the door open (note striker  32  is no longer retained in recess  24 ). Unlatching occurs via a user actuating either the inside handle  16  or outside release handle (not shown) thereby causing pawl  30  to lift out of abutment with either of surfaces  26  or  28 . Because claw  20  is biased in an anti-clockwise direction as shown in  FIG. 3A , anti-clockwise rotation of the claw  20  occurs, thereby releasing striker  32 . This simultaneously causes block link  36  to be engaged by an abutment surface  34  of the claw  20  and thus to be lifted. As can be seen most clearly from  FIG. 3B , in this position it is not possible for lever  42  to further actuate pawl  30  since rotation of lever  42  is prevented by projection  40 . Therefore, when the user pulls handle  16  in order to close and latch the door  10 , this pulling action is prevented from causing the latching action to fail due to the pawl  30  being lifted out of contact with the claw  20  as the claw  20  rotates during contact with the striker  32 . 
   It is apparent that activation of lever  42  in direction X maintains the blocking link  36  in its lifted position even whilst claw  20  rotates clockwise during contact with the striker  32 . Only once actuation of lever  42  ceases (when the door  10  is closed and the latch is latched) will blocking link  36  return to its rest position enabling a subsequent actuation of lever  42  to release the latch  18 . Pawl  30 , block link  36 , and lever  42  are included in a release linkage  60 . 
     FIG. 4  illustrates schematically the electrical mechanism constituting the operable connection between inside handle  16  and latch  18  mounted in the door is of a vehicle  60 . It can be seen that the mechanism comprises an inside handle switch  52  arranged so as to signal a controller  50  when the handle  16  is actuated and a door ajar sensor  48  arranged so as to signal the controller  50  when the door  10  is ajar (open). The controller  50  may be in the form of a stand-alone microprocessor located within the door  10  as shown in  FIG. 4  or a vehicle ICU which may be located under the bonnet of the vehicle, for example. In response to the input signals from switch  52  and sensor  48 , the controller  58  determines whether latch power actuator  54  (e.g. an electric motor) is to cause the unlatching of the latch  18  and signals the actuator accordingly. The power actuator  54  is arranged so as to lift pawl  30  when an unlatching signal is sent by controller  50 . In use, the controller  50  does not send an unlatching signal to the actuator  54  when sensor  48  indicates that the door is ajar. 
   The operational sequence of the mechanism is illustrated by a flow chart of  FIG. 5 . In order to determine whether the latch is to be operated electrically, in one embodiment a small force applied to handle  16  is sufficient to cause the latch to be unlatched electrically, but that if electrical operation is not possible, a larger force must be exerted on the handle  16  to cause mechanical unlatching. Thus, electrical unlatching takes precedence. 
   It is therefore apparent that both the electrical and mechanical connections are provided with safeguards to prevent the latch being mis-set when the door is being pulled to a closed position, enabling a single handle  16  to act as door engagement means and inside release means. 
   It should be noted that references to orientations such as “vertical” and directions such as “anticlockwise” have been used for convenience within the description and are not to be considered as limiting. 
   It should be understood that numerous changes may be made within the scope of the present invention. For example, a break rather than a block may be provided in the latch linkage to prevent the latch being mis-set and the mechanism may be adapted for use with other known types of latches. The choice between electrical and mechanical unlatching may be left to the vehicle user by, for example, electrical unlatching being initiated by pulling handle  16  inwardly and mechanical actuation by lifting the handle upwardly. In this embodiment, the block link may be dispensed with since mechanical unlatching would not be caused by pulling the door into a closed position under normal operational circumstances. Rather than the electrical connection comprising a door ajar sensor, a sensor to determine the state of the latch could be employed. The door ajar sensor may be provided in series with the inside handle switch and in which case, a controller may be dispensed with. 
   The foregoing description is only exemplary of the principles of the invention. 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, so that one of ordinary skill in the art would recognize that certain modifications would come within the scope of this invention. It is, therefore, to be understood that within the scope of the appended claims, the invention may be practiced otherwise than as specially described. For that reason the following claims should be studied to determine the true scope and content of this invention.