Abstract:
A latch assembly includes a mouth for receiving a striker and a releasable latch bolt mechanism for automatically retaining the striker within the mouth. The mouth includes a deformable unitary jaw member defining opposing first and second jaw walls and an intermediate base portion. The jaw walls and the base portion are arranged to engage the striker. The base portion is configured to deflect inwardly upon receiving the striker. The inward deflection of the base portion causes a partial closure of the unitary jaw member by way of associated deflection of at least one of the jaw walls to reduce the distance between the jaw walls.

Description:
REFERENCE TO RELATED APPLICATION  
       [0001]     This application claims priority to United Kingdom Patent Application GB 0423702.0 filed on Oct. 26, 2004.  
       BACKGROUND OF THE INVENTION  
       [0002]     The present invention relates generally to a latch assembly for a vehicle and to a striker. More particularly, the present invention relates to a latch assembly including a latch and a striker having cooperating engagement means.  
         [0003]     Light commercial vehicles, such as panel vans (i.e., vans in which a load space is enclosed), typically include a relatively large rear opening that is closeable by two rear doors hinged to a rear most edge of each side of the van. A latch is typically provided partially up a shut-face of one of the rear doors. The latch is arranged to latch with a complementary striker provided on the shut-face of the other of the rear doors when the doors are closed. Typically, the latch may also operate shoot bolts or supplementary latches which are fitted to upper and lower edges of the door to which the latch is fitted and which are arranged to engage in a complementary hole or a striker in a door surround. The shoot bolts or supplementary latches provide additional latching strength to the doors when closed to resist flexing of the relatively tall doors when the vehicle is in motion and to resist any attempts to force the latched doors open.  
         [0004]     For the hingeable mounting to function, axes of the typically two hinges used to mount each door must be co-axially arranged. The sides of such vans often converge towards the van roof, meaning that it may be necessary to mount the hinges some distance below the top of the shut-face of each door. Furthermore, a significant proportion of the structural integrity of the rear of the van load space is imparted by the rear doors when shut. Thus, with the rear doors open, a certain amount of deflection of the roof and the side panels of the rear load space may occur, and a certain amount of flexing of the doors may also occur. Wear can also occur to the hinges over extended periods of use. The combination of these factors may lead to difficulties in locating the latch with the striker and/or the shoot bolts in the respective holes due to movement of the rear doors out of their proper alignment. This may in turn lead to difficulties in satisfactorily latching the doors.  
         [0005]     Additionally, the deflection of the roof, the side panels and the doors while the vehicle is in motion may lead to rattling caused by play between the latch and the striker. This may in turn lead to increased wear on both the latch and the striker, as well as higher noise levels.  
         [0006]     It has been proposed to overcome these problems by introducing an assembly within the mouth of the latch which attempts to grip (but not retain) the striker when the striker is in a closed position. Such an embodiment is shown in EP0723620. However, displacement of the gripping assembly inwardly into the body of the latch is necessary for the assembly to grip the striker. Furthermore, several distinct components are required to achieve the gripping of the striker, which further adds to the cost and complexity of the latch.  
         [0007]     The present invention seeks to overcome, or to at least mitigate, the problems of the prior art.  
       SUMMARY OF THE INVENTION  
       [0008]     Accordingly, one aspect of the present invention provides a latch assembly including a mouth for receiving a striker and a releasable latch bolt mechanism for automatically retaining the striker within the mouth. The mouth includes a deformable unitary jaw member defining opposing first and second jaw walls and an intermediate base portion. The first and second jaw walls and the base portion are arranged to engage the striker. The base portion is configured to deflect inwardly upon receiving the striker. The inward deflection of the base portion causes a partial closure of the unitary jaw member by way of associated deflection of at least one of the first and second jaw walls to reduce a distance between the first and second jaw walls.  
         [0009]     A second aspect of the present invention provides a striker assembly for a latch mechanism having a striker bar attached to a striker support and an overmold arranged to cover a part of the striker bar and a part of the striker support. The overmold is arranged to engage the striker bar and the striker support to prevent rotation of the overmold relative to the striker support.  
         [0010]     A third aspect of the invention provides the latch assembly of the first aspect of the invention and the striker assembly of the second aspect of the invention. The striker overmold and the inner surfaces of the unitary jaw member are dimensioned such that when the striker bar is retained by the latch bolt, the first and second jaw walls compress the overmold. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0011]     Embodiments of the present invention will now be described, by way of example only, with reference to the accompanying drawings in which:  
         [0012]      FIG. 1  is a partially exploded isometric view of the latch assembly according to a first aspect of the invention;  
         [0013]      FIG. 2  is an isometric view of the latch assembly of  FIG. 1  showing the opposite side of the latch assembly to that shown in  FIG. 1 ;  
         [0014]      FIG. 3  is a side view of the latch assembly of  FIG. 1 , showing hidden detail;  
         [0015]      FIG. 4  is an isometric view of a striker of the second aspect of the invention;  
         [0016]      FIG. 5  is an isometric view of the striker of the second aspect of the present invention showing the deformable unitary door member of the first aspect of the invention;  
         [0017]      FIG. 6  is a partially exploded isometric view of the latch assembly of  FIG. 1  showing part of the striker of  FIG. 4  in the closed position; and  
         [0018]      FIG. 7  is a side view of the latch assembly of  FIG. 3  showing part of the striker of  FIG. 4 . 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT  
       [0019]      FIGS. 1 and 2  illustrate a latch assembly  10  including a latch chassis  12  on which a latch bolt in the form of a rotatable claw  14  and a pawl  16  are pivotally mounted. The pawl  16  is typically in driven engagement with a latch operator, such as an inside release handle of a vehicle door to which the latch assembly  10  is mounted, either directly or more usually indirectly, via a primary latch (not shown) itself controlled by an inside handle and/or an outside handle. The primary latch has an output to the pawl  16  via a bowden cable or the like (not shown) and a release lever  17 .  
         [0020]      FIG. 1  shows the latch assembly  10  in a closed latched position with the claw  14  configured to retain a striker bar  82  of a striker assembly  70  within a claw recess  24  (see  FIG. 7 ). The claw  14  is retained in a closed position by the pawl  16 . The pawl  16  may be lifted by the release lever  17  to release the claw  14 .  
         [0021]     The sides of the latch chassis  12  are enclosed by side plates  13  which define latch mount plates  15 . The latch chassis  12  and the side plates  13  define a mouth  22  for receiving the striker bar  82 , thereby allowing the striker to be retained in the claw recess  24  in the closed position by engagement of the pawl  16  with the claw  14  (as shown in  FIG. 1 ).  
         [0022]     With reference now to  FIG. 3 , the mouth  22  of the latch assembly  10  houses a jaw member  30 . The jaw member  30  is of unitary construction and is formed from a deformable plastics material (e.g., a nitrile rubber). However, the jaw member  30  can be formed from any material having suitable plastic properties. The jaw member  30  includes an upper jaw wall  34  and a lower jaw wall  36  which extend outwardly from a base portion  32 . A upper leg  38  and a lower leg  40  extend inwardly from the base portion  32 . The jaw member  30  is advantageously symmetrical and can be used for both upper and lower supplementary latches without adaptation.  
         [0023]     The inner profile of the latch chassis  12  and the outer profile of the upper leg  38  and the upper leg  40  define a deflection cavity  42  which allows the base portion  32  to deflect inwardly (i.e., away from mouth  22 ), as will be discussed further below.  
         [0024]     The upper jaw wall  34  and the lower jaw wall  36  define an inner surface  44  and  46 , respectively. Abutting the inner surfaces  44  and  46  are a first striker guide  48  and a second striker guide  50  which are provided to protect the upper jaw wall  34  and the lower jaw wall  36 , respectively, and also be of lower friction than the jaw member  30  to reduce the latching effort required. The first striker guide  48  and the second striker guide  50  guide an associated striker towards the base portion  32 , as will be discussed in further detail below. The first striker guide  48  and the second striker guide  50  are advantageously formed integrally from the same material as the latch chassis  12 , which as described above also houses and supports the claw  14 , the pawl  16 , the springs and the like. The first striker guide  48  and the second striker guide  50  may be made from any suitable engineering plastics such as PBT, and their cantilevered shape makes them relatively flexible.  
         [0025]     With reference now to  FIG. 4 , the striker assembly  70  includes a main body  72  formed from a unitary pressed steel sheet, a first striker mount plate  74 , a second striker mount plate  76 , a first support arm  78  and a second support arm  80 . The first support arm  78  and the second support arm  80  support the striker bar  82 . A striker overmold  84  covers part of the striker bar  82  and part of the main body  72 . The striker overmold  84  has a first end  86 , and second end  88 , an upper surface  90  and a lower surface  92  (only the upper surface  90  is visible in  FIGS. 5 and 6 ). The striker overmold  84  is preferably resilient and may be made from a suitable thermoplastic elastomer or the like. The remainder of the striker bar  82  is left bare to be engaged by the claw  14 .  
         [0026]     In use, the latch assembly  10  and the striker assembly  70  will cooperate as follows. The striker assembly  70  is attached by way of the first striker mount plate  74  and the second mount striker plate  76  to a vehicle door surround (not shown for clarity). The latch assembly  10  will be fixed by way of the side plate  13  to a vehicle door (also not shown for clarity). Typically, the vehicle will be a panel van, and the latch assembly  10  will operate as a supplementary latch to a primary latch and be secured near an upper edge or a lower edge of a rear door. The striker assembly  70  will be secured near the load floor or the roof of the rear of the van. The striker assembly  70  is typically arranged such that the striker bar  82  is substantially horizontal (i.e., at 90 degrees to the axis of the door hinges), but this need not necessarily be the case. The latch assembly  10  is typically arranged such that an axis of rotation of the claw  14  is substantially horizontal. The latch assembly  10  is oriented as shown in the drawings when positioned near the bottom of the door and will be inverted when positioned near the top of the door.  
         [0027]     When the vehicle door is closed, the striker bar  82  and the striker overmold  84  are initially received in the mouth  22  of the latch assembly  10 . As the door is moved further to a closed position, the first end  86  of the striker overmold  84  comes into contact with the base portion  32  of the jaw member  30 , as shown in  FIGS. 5 and 6 . Final movement of the door causes the striker bar  82  to move further inwardly into the mouth  22  of the latch assembly  10 . This movement causes deflection of the jaw member  30 , as will be discussed further shortly. The deflection of the jaw member  30  allows the striker bar  82  to move inwardly, which in turn allows the claw  14  to automatically catch the striker bar  82  within the claw recess  24 . Since the claw  14  is retained by the pawl  16 , the striker bar  82  is held in the closed position. This leaves the jaw member  30  in a permanent state of deflection once the striker bar  82  is held in the closed position. This deflection causes the jaw member  30  to compress the striker overmold  84  to reduce movement thereof in the following manner.  
         [0028]     With reference to  FIG. 7 , closing the vehicle door causes the striker bar  82  and the striker overmold  84  to move in direction A towards the base portion  32 . This causes the base portion  32  to deflect into the deflection cavity  42 . In turn, this causes the compression of the inner portions of the upper leg  38  and the lower leg  40 , which causes migration of the material forming the upper leg  38  and the lower leg  40  in the direction of arrows B. In addition, deflection of the base portion  32  in the direction A causes a load to be applied to the base of the upper jaw wall  34  and the lower jaw wall  36  in the direction of arrows C. The net effect of the loading on the jaw member  30  causes the upper jaw wall  34  and lower jaw wall  36  to be urged towards one another in the direction of arrows D. Consequently, the upper jaw wall  34  and the lower jaw wall  36  apply a load to the striker overmold  84  via the first striker guide  48  and the second striker guide  50 .  
         [0029]     This load acts to “grip” the striker bar  82  and the striker overmold  84  to reduce relative movements between the striker assembly  70  and the latch assembly  10  in the so-called Z-direction (i.e., vertically) when the latch and the striker are fitted in either of the orientations described above.  
         [0030]     When the pawl  16  is disengaged from the claw  14  to release the latch assembly  10 , the compressed nature of the striker bar to jaw member relationship promotes the movement of the striker bar  82  out of the mouth as the potential energy in the jaw member  30  is released.  
         [0031]     The latch assembly  10  of the present invention could be used in conjunction with a striker assembly different from that described herein. Such an arrangement would still offer benefits over the prior art devices. However, the combination of the striker assembly  70  and the latch assembly  10  as described in the present invention confers substantial advantages over the prior art for the following reasons.  
         [0032]     There exists a large area of surface contact between the upper surface  90  and the lower surface  92  of the striker overmold  84  and the first striker guide  48  and the second striker guide  50 , respectively. This increases the level of grip achieved between the latch assembly  10  and the striker assembly  70 , which further reduces the extent of the movement realized between the two assemblies.  
         [0033]     Additionally, the construction of the striker assembly  70  means that there is virtually no rotation of the striker overmold  84  with respect to the vehicle door. This ensures that a secure connection exists between the latch assembly  10  and the striker assembly  70 , which further decreases the relative movement observed between the latch assembly  10  and the striker assembly  70 .  
         [0034]     The foregoing description is only exemplary of the principles of the invention. Many modifications and variations are possible in light of the above teachings. It is, therefore, to be understood that within the scope of the appended claims, the invention may be practiced otherwise than using the example embodiments which have been specifically described. For that reason the following claims should be studied to determine the true scope and content of this invention.