Abstract:
A power actuator arrangement including a power drive assembly having a first powered position and a second powered position and an output means, the output means being unmoveable by the power drive assembly between a first detent position corresponding to the first powered position and a second detent position corresponding to the second powered position following powered operation, the output means being retained in the first or second detent positions by a detent bias force provided by a detent arrangement, the output means being independently movable by an independent force between the first and second detent positions, the independent force acting to overcome the detent bias force such that during independent movement the independent force substantially does not move the power drive assembly between its first powered and second powdered positions.

Description:
BACKGROUND OF THE INVENTION  
         [0001]    The present invention relates to power actuator arrangements and in particular power actuator arrangements for providing a child safety on/off feature, a lock/unlock feature or a superlock/unsuperlock feature on a car door latch.  
           [0002]    When known power actuator arrangements are used for locking and unlocking of a vehicle door latch, a provision is made for manual override. Thus a vehicle door latch which has been power unlocked by a central door locking system can subsequently be manually locked by the driver depressing a cill button or the like. Under such circumstances the cill button preferably has to be provided with a detent position to ensure that the cill button stays in either a fully raised or fully lowered position and not in a midway position. Under such circumstances the motor of the power actuator arrangement has to be powerful enough to not only drive the latch mechanism between lock and unlock but also has to overcome the detent forces.  
           [0003]    In particular the detent forces have to be sufficiently high to provide a good tactile feel and also to ensure that inertia forces resulting from a road traffic accident do not overcome the detent forces and change the state of the lock.  
         SUMMARY OF THE INVENTION  
         [0004]    Thus according to the present invention there is provided a power actuator arrangement including a power drive assembly having a first powered position and a second powered position and an output means, the output means being moveable by the power drive assembly between a first detent position corresponding to the first powered position and a second detent position corresponding to the second powered position following powered operation, the output means being retained in the first or second detent positions by a detent bias force provided by a detent arrangement, the output means being independently moveable by a independent force between the first and second detent positions, the independent force acting to overcome the detent bias force such that during independent movement the independent force substantially does not act to move the power drive assembly between its first powered and second powered positions.  
           [0005]    According to a further aspect of the present invention there is provided a power actuator arrangement including a power drive assembly and an output means, the output means being movable by the power drive assembly between first and second positions and being independently movable by an independent force between the first and second positions such that the first and second positions are detent position and during independent movement between the first and second positions the independent force has to overcome a detent force in which the power drive assembly has to overcome a reduced detent force when moving the output means between the first and second positions.  
           [0006]    These and other features of the present invention will be best understood from the following specification and drawings. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0007]    The various features and advantages of the 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:  
         [0008]    [0008]FIG. 1 is a front view of the power actuator arrangement according to the present invention during powered operation;  
         [0009]    [0009]FIG. 2 is an isometric view of the output means of FIG. 1;  
         [0010]    [0010]FIG. 2A is a partial cut away view of FIG. 1;  
         [0011]    FIGS.  3  to  6  are front, isometric, rear and side views of the power actuator arrangement of FIG. 1 being used to actuate a child safety arrangement of a door latch; and  
         [0012]    [0012]FIG. 7 is a view of a further power actuator according to the present invention. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT  
       [0013]    With reference to FIGS. 1 and 2 there is shown a power actuator arrangement  10  which includes a power drive assembly  12 , an output means  14  and a detent arrangement  84 . The power drive assembly includes a power actuator in the form of a motor  16  driving a pinion  18  which engages and drives gear  20 . Gear  20  is rotationally fast with a drive abutment in the form of a crank pin  32 . The drive pin  18 , gear  20  and crank pin  32  combine to form a transmission path of the power drive assembly.  
         [0014]    The detent arrangement  84  includes a first member in the form of a cam  22  and a second member in the form end portion  23  of output means  14 .  
         [0015]    The cam  22  is secured rotationally fast to gear  20 . Cam  22  has a cam surface  24  being profiled with base circle portion  26  and  27  (also known as third and fourth outwardly facing surfaces) and two symmetrically diametrically opposed cam lobes  28  and  30  (also known as first and second outwardly facing surfaces).  
         [0016]    End portion  23  includes a twin lobed recess  34  having first arcuate portion  36  and second arcuate portion  38 , the centres of arcuate portions  36  and  38  being different. The first and second arcuate portions combine to form a wasted region  40  of width W.  
         [0017]    Accurate portion  36  includes portion B (see FIG. 2A) ie that portion of arcuate portion  36  abutted by one of the cam lobes (in the case of FIG. 3, cam lobe  30 ) when the output means  14  is in the lowered position. A similar portion C of arcuate portion  38  can be defined as that portion abutted by one of the cam lobes when the output means is in the raised position. Corresponding portions D of arcuate portion  36  and E of arcuate portion  38  can be defined as those portions contacted by one of the cam lobes  28  and  30  when the output means  14  is in the lowered and raised position respectively. The combination of portions B and C combine to form a first inwardly facing surface F of the end portion  23  and the combination of portions D and E combine to form a second inwardly facing surface G of the end portion  23 .  
         [0018]    Wall  33  defines the twin-lobbed recess  34  and is relatively thin. Proximate and facing the twin lobbed recess  34  is a flange portion  42  having a driven recess  44  and a first and second stop abutments  46  and  48 .  
         [0019]    An arm  50  of output means  14  is integrally formed with the wall  33  and flange portion  42  and includes at its distal end  52  an arcuate slot  54 . The cam  22  is positioned within the recess  34 .  
         [0020]    The output means  14  can be moved reciprocally in the direction of arrow A by selective operation of the motor between a lowered first detent position (as shown in FIGS. 1 and 3) and a raised second detent position. Additionally the output means  14  can be manually moved between the first and second detent positions by actuation of the pin  80 , situated in slot  54 , in the direction of arrow A.  
         [0021]    The power drive assembly has a first powered position as shown in FIG. 3 wherein crank pin  32  is situated at the 12 o&#39;clock position and a second powered position wherein crank pin  32  is situated at the 6 o&#39;clock position when viewing FIG. 3. As described below when the output means is moved by the power drive assembly between the first detent position and second detent position, these detent positions correspond respectively to the first and second powered positions of the power drive assembly.  
         [0022]    However, as further described below, following independent movement of the output means the output means can be moved to its second detent position whilst the power drive assembly remains in its first powered position and similarly the output means can be moved to its first detent position whilst the power drive assembly remains in its second powered position.  
         [0023]    With the actuator arrangement positioned as shown in FIG. 3 the crank pin  32  abuts first stop abutment  46  and the cam lobe  28  and  30  are positioned horizontally relative to each other when viewing FIG. 3 and are in contact with first arcuate portion  36  of twin lobed recess  34 .  
         [0024]    It should be noted that the diameter across cam lobes  28  and  30  is substantially the same as the diameter across first arcuate portion  36  and second arcuate portion  38 , and that the diameter across the base circle portion  36  is substantially similar to distance W across the wasted region  40 .  
         [0025]    Lifting of pin  80  (as described below) causes the output means  14  to move upward when viewing FIG. 3 such that the wasted region  40  rides over cam loads  28  and  30  thus springing wall  33  apart. Continued movement of the output means upward results in the cam lobes  28  and  30  snapping into engagement with second arcuate portion  38 .  
         [0026]    Thus the cam lobes  28  and  30  in conjunction with waste portion  40  provide for an upper and lower detent position of the output means  14 .  
         [0027]    It should be noted that the cam lobes  28  and  30  are symmetrical as is either side of the wasted portion. Thus manual movement of the output means  40  between its first and second position does not produce any turning moment on cam  22 . Thus there is no tendency for cam  22  to rotate during manual movement.  
         [0028]    With the power actuator arrangement  10  positioned as shown in FIG. 3 the motor can be energised such that it rotates in a clockwise direction causing the gear  20  to rotate in an anti-clockwise direction. Thus crank pin  32  will move from the twelve o&#39;clock position anti-clockwise, in the direction of arrow R, to the four o&#39;clock position as shown in FIG. 1 whereupon it will engage driven recess  44  and cause the output means  14  to move from its first lower to its second raised position. Continued energization of the motor will cause the crankpin  32  to continue to move in an anticlockwise direction past the twelve o&#39;clock position and around to the six o&#39;clock position whereupon it will abut second stop abutment  48 .  
         [0029]    It should be noted that the crank pin  32  has just started to engage in recess  44  when crank pin  32  is at the four o&#39;clock position and consequently the output means  14  is fully raised when the crank pin  32  is in the two o&#39;clock position. Note that cam lobe  28  moves between a seven o&#39;clock and five o&#39;clock position and cam lobe  30  moves between a one o&#39;clock and eleven o&#39;clock position during movement of the output means  14  from its first to second position and that wasted portion  14  thus only has to pass over base circle portion  26 . Since the width W of wasted portion  40  is substantially the same as the diameter of the base circle portion  26  there is no detent force to overcome when the output means is moved between its first and second positions by the motor  16 .  
         [0030]    With the output means raised to its second position by the motor  16 . Actuation of the motor in an anticlockwise direction will cause drive gear  20  to rotate through 540° in a clockwise direction such that crank pin  32  moves one and half turns from a six o&#39;clock to the twelve o&#39;clock position moving the output means  14  from its raised second position to its lowered first position.  
         [0031]    In the event of manual movement of output means  14  from its lowered first position as shown in FIG. 3 to its raised second position, in the absence of movement of the motor, subsequent actuation of the motor in a clockwise direction will result in anti clockwise rotation of the gear  20 . However the crank pin  32  will only move through 180° until such time as it contacts second stop abutment  48  which has been moved to a raised position as a result of manual movement of the output means.  
         [0032]    As described above, in this case the power actuator arrangement drives a vehicle car door latch between a child safety on and a child safety off position as described below.  
         [0033]    A latch arrangement  8  includes the power actuator arrangement  10  mounted on a chassis  60 . An inside handle lever  62  (connected to an inside door handle) and an inside release lever  64  are both pivotally mounted on the chassis  60  about pivot  66 . A child safety link  68  lies substantially parallel to the inside handle lever  62  and inside release lever  64  and includes at an upper portion a clutch pin  70  which slideably engages slot  72  of inside handle lever  62 . Projecting on other side of child safety link  78  is pin  80  which engages slot  54  as described above.  
         [0034]    A lower portion of the child safety link  68  engages with a crank pin  74  of child safety operating crank  76 .  
         [0035]    Operation of an inside door handle causes inside handle lever  62  to rotate anticlockwise as shown in FIG. 6 such that clutch pin  70  contacts clutch abutment  78  of inside release lever  64  causing inside lever  64  to also rotate anticlockwise resulting in opening of the door.  
         [0036]    However when the clutch pin  70  is moved to an upper portion of slot  72  operation of the inside door handle results in clutch pin  70  passing over clutch abutment  78  resulting in a door that cannot be opened by operation of the inside door handle (child safety on).  
         [0037]    Clutch pin  70  can be moved up or down slot  72  either by actuation of the motor or by manual means as follows.  
         [0038]    Motor actuation causes output means  14  to move between first and second positions. The co-operation of pin  80  with arcuate slot  54  causes the child safety link  68  to move to a raised or lowered position thus positioning clutch pin  70  in a raised or lowered position. Raising or lowering of the child safety link  68  by the motor has the result of rotating the child safety-operating crank.  
         [0039]    Alternatively rotation of the child safety operating crank by insertion of a screwdriver or the like into slot  82  causes clutch pin  70  to move between an upper and lower position. Such manual movement causes pin  80  to drive the output means  14  between its lower first position and upper second position. Because the first and second positions of the output means  14  are detent positions, the detent can be felt by an operator rotating the child safety operating crank with a screwdriver or the like. Thus the operator can be confident that the child safety is on or off as appropriate.  
         [0040]    As mentioned above the power actuator arrangement is not limited to changing the state of a latch between a child safety on and child safety off condition.  
         [0041]    Furthermore the output means need not operate in a linear manner but could be arranged as a lever  14 ′ (see FIG. 7) pivotable about axis  11 .  
         [0042]    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.