Abstract:
An inside door release mechanism for a vehicle comprises first and second inputs arranged to be mounted in a mutually spaced relationship on a door inner face and an output to a latch wherein the mechanism is so constructed and arranged to be capable of causing the latch to be unlatched when both inputs are actuated simultaneously.

Description:
This application claims priority to United Kingdom (GB) patent application number 0122633.1 filed on Sep. 20, 2001. 
     BACKGROUND OF INVENTION 
     The present invention relates to an inside door release mechanism. More particularly, the present invention relates to an inside door release mechanism for a vehicle. 
     Vehicle doors, 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 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. 
     It is known to fit power unlatching systems to vehicles. Some systems merely require a switch to be pressed in order to send an unlatching signal to a corresponding door latch. However, there is a risk of accidental actuation if such switches are mounted at an accessible location in the vehicle interior. This is dangerous for the vehicle occupants, particularly if the vehicle is in motion, since they risk falling out of the vehicle. 
     SUMMARY OF INVENTION 
     The present invention seeks to overcome or at least mitigate the aforesaid problems. 
     One aspect of the present invention is an inside door release mechanism for a vehicle comprising first and second input means arranged to be mounted in a mutually spaced relationship on a door inner face and a latch wherein the mechanism is so constructed and arranged to cause the latch to be unlatched when both input means are actuated simultaneously. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Embodiments of the present invention will now be described, by way of example only, with reference to the accompanying drawings in which: 
         FIG. 1  is a perspective view of an inner face of a door incorporating the mechanism of the present invention; 
         FIG. 2  is a schematic view of a vehicle incorporating the mechanism of the present invention; and 
         FIG. 3  is a flow chart illustrating the functioning of the mechanism of the present invention. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Referring to  FIG. 1 , a vehicle side passenger door  10  is shown and comprises an interior trim panel  12  having an arm rest  14  mounted thereon. A handle portion  16  is integrally provided with the arm rest  14  and a strain gauge  18  (hereinafter referred to as the handle strain gauge) is provided to mount the front of the handle  16  to the trim panel  12  such that pulling on the handle  16  produces an output, as described in greater detail below. A further strain gauge  20  in the form of a panel (hereinafter referred to as the trim strain gauge) is mounted on the trim panel  12  above and towards the rear of the arm rest portion  14  such that pressing thereon produces an output. 
     Gauge  20  is located such that if a vehicle user grasps handle  16  and rests his/her arm on the upper face of arm rest  14  the elbow or lower arm will contact the strain gauge panel  20 . Although the gauges  18  and  20  are visible in  FIG. 1 , they may in alternative embodiments be hidden for aesthetic reasons. In this embodiment, the strain gauges  18 ,  20  comprise first and second input means of door inner release means. 
     A power door latch  22  is mounted on the rear face  23  of the door. 
     Turning now to  FIG. 2 , a vehicle  50  incorporating door  10  is illustrated schematically. At the heart of the door release mechanism is a controller  30  which may be a standalone microprocessor incorporated into the door  10  or, as this embodiment, is an overall vehicle ICU that is conventionally located under the bonnet (hood) of the vehicle and is also tasked with controlling other vehicle functions (not shown). The controller receives inputs from the handle and trim strain gauges  18  and  20  as well as an input from the door lock status indicator  26  regarding the current locking status of latch  22 . 
     A vehicle motion sensor  28  such as a radar speed detector or the like provides a further input to the controller  30  when the vehicle  50  is travelling in excess of a predetermined speed (e.g. 3 km/h). 
     In response to the inputs from the aforesaid components, the controller determines the appropriate state of the door latch  22  and signals a power door latch actuator  24  and/or door lock actuator  25  accordingly. The door lock actuator  25  is capable of communicating its current lock state to lock status indicator  26 . It should be appreciated that similar components and inter connections may be provided for each door provided on the vehicle, and that individual controllers may be provided for each door, or a single controller  30  may control the function of all doors. 
     For the avoidance of doubt, following terms relating to latch locking states are now defined: 
     A latch is in an unlocked security condition when operation of an inside release means or an outside release means causes unlatching of the latch. 
     A latch is in a locked security condition when operation of an outside release means does not unlatch the latch but operation of an inside release means does unlatch the latch. 
     A latch is in a superlocked security condition where operation of an outside or an inside release means does not unlatch the latch. In particular it should be noted that multiple operations of the inside and outside release means, in any sequence, does not unlatch the latch. 
     A latch is in a child safety on security condition when operation of an inside release means does not unlatch the latch but operation of an outside release means may or may not unlatch the latch depending on whether the latch is an unlocked or locked condition. 
     Override unlocking is a function whereby operation of an inside release means, with the latch in a locked condition, causes unlocking of the latch. 
     Note that override unlocking is applicable to a latch in a locked child safety off condition, and is also applicable to a latch in a locked child safety on condition. In particular starting from a locked child safety on condition of a latch having override unlocking, an actuation of the inside release means will unlock the door, but this operation or any subsequent operation of the inside release means will not unlatch the door since the child safety feature is on. Nevertheless, once the latch has been unlocked by actuation of the inside release means, a subsequent operation of the outside release means will unlatch the latch. In particular it should be noted that this situation is different from a superlocked latch since in the former case a particular sequence of release means operations, i.e. operation of the inside release means followed by operation of the outside release means, will unlatch the latch. This is not the case for superlocking. 
     One pull override unlocking is a function whereby with the latch in a locked child safety off condition a single actuation of the inside release means results in unlocking of the door and also unlatching of the door. 
     Two pull override unlocking is a function, whereby with the latch in a locked child safety off condition a first actuation of the inside release means results in unlocking of the latch but does not result in unlatching of the latch. However, a further operation of the inside release means will then cause the latch to unlatch. 
     This embodiment, the latch  22  has a child safety function and one a pull override unlocking function, although in other embodiments, the child safety function may be omitted (e.g. for front driver doors) and the latch may have two pull override unlocking. 
     The operation of the mechanism is as illustrated by the flow chart of  FIG. 3 . In use, a user seated in the vehicle grasps handle  16  and rests his/her forearm along arm rest  14 . Then, by applying an inwardly directed tensile force to handle  16  and an outwardly directed compression force to strain gauge  20 , output signals from both gauges are simultaneously sent to controller  30 . If both signals exceed a predetermined threshold value, the controller  30  then goes on to determine the locked state of latch  22  from lock status indicator  24 . If the latch is superlocked, no unlatching signal is sent to door latch actuator  24 . If child safety is on and the latch is locked, the controller  30  signals the door lock actuator  25  to unlock the latch  22  but not to unlatch it. The door lock actuator  25  signals the lock status indicator  26  to provide an update of its status. Only if the latch  22  is locked or unlocked and the output from the motion sensor  28  is low will unlatching occur. The controller  30  sends the appropriate signal to the door latch actuator  24  in order to achieve this. 
     In alternative embodiments, a memory may be associated with the controller  30  to store the current lock status and door lock status indicator  25  may be omitted. 
     Thus, is apparent that the arrangement of the strain gauges  18  and  20  substantially prevents the accidental unlatching of latch  22  and that in a preferred embodiment, vehicle occupant safety is further enhanced by integrating a motion sensor into the mechanism so as to prevent accidental unlatching whilst the vehicle is in motion. 
     Note that the orientations such an “inner” and “outer” as referred to herein relate to orientations of a door when installed in a vehicle. Nevertheless, such terms should not be construed as limiting. 
     It is envisaged that numerous changes may be made within the scope of the present invention. For example, alternative input means, such as switches, force transducers or even a mechanical linkage but may be provided in place of the strain gauges. The positioning of the input means may be altered. For example, one gauge may be provided on the handle so that an output is generates when it is squeezed.