Abstract:
A window fastener having a mounting base ( 21 ), a latching flap ( 12 ) moveably coupled thereto, a handle ( 14 ) and a latching tongue ( 15 ). the handle ( 14 ) is movable between first and second positions and is coupled to the latching tongue ( 15 ) so that the latching tongue moves the latching flap ( 18 ) when the handle ( 14 ) moves to a latching position. A movement inducing mechanism ( 34, 41 ) operable by the handle ( 14 ) causes movement of the flap ( 12 ) to occur when the handle is moved from the latching position to a non-latching position.

Description:
BACKGROUND OF THE INVENTION 
     This invention relates to a window fastener. 
     To latch a projected hung window in a closed position, it is common to have one or more handle operated fasteners mounted with the sash. Each fastener engages with the window frame when the sash is in the closed position to latch the sash closed. It is widely known to construct the fastener so that a tongue formed integrally with the handle wedgingly engages with a wedge plate mounted with the window frame. 
     In our European patent specification 0133051, there is disclosed a window fastener where a separate wedge plate is not required. In EP 0133051 there is disclosed a handle which, during movement between first and second positions, causes a flap to move between latching and release positions. Thus when the window sash is moved to a closed position the handle can be operated to cause the flap to overlap the window frame and thereby retain the sash in a closed position. However, moving the handle to the other position causes the flap to move to a release position and permits the window sash to be opened. A window fastener of this type has been very successful commercially. 
     A draw back with the window fastener of EP 0133051 is that the fastener is “handed” because the tongue engages an upstand on the flap to cause the flap to move from a latching position to a non-latching position. Accordingly a manufacturer must provide right and left hand fasteners. This leads to the requirement that the manufacturer must have stock holdings of left and right handed fasteners and can result in the need for different manufacturing runs for the different components for the left and right hand fasteners. 
     SUMMARY OF THE INVENTION 
     It is therefore an object of the present invention to provide a window fastener which has a latching flap operable by a handle, the fastener being of a construction where it is not required that a handle tongue be used to create movement of the flap from its latching position. 
     Broadly according to one aspect of the invention there is provided a window fastener having a mounting base, a latching flap moveably coupled thereto, a handle and a latching tongue, the handle being movable between first and second positions and coupled to the latching tongue whereby the latching tongue moves the latching flap when the handle moves from the first position to the second position, characterised in that the fastener includes a movement inducing means operable by said handle, the movement inducing means being engageable with the flap to cause movement of the flap when the handle is moved from the second position to the first position. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a perspective view of the window fastener according to the invention, 
     FIG. 2 is a similar view but with the fastener in a non latching position, 
     FIG. 3 is an underside perspective view of the arrangement shown in FIG. 1, 
     FIG. 4 is a perspective underside view of the arrangement shown in FIG. 2, 
     FIG. 5 is an exploded view, 
     FIG. 6 is a further exploded view, 
     FIG. 7 is a perspective view of the flap, 
     FIG. 8 is a perspective view of the cam washer, and 
     FIG. 9 is a plan view of the cam when viewed from the side opposite to that uppermost in the view shown in FIG.  8 . 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
     The window fastener according to the present invention in one preferred embodiment includes a mounting  10  with which a handle  11  is pivotally mounted. A flap  12  is pivotally mounted to the mounting  10  and pivots about an axis which is substantially at right angles to the axis about which the handle  11  pivots. 
     The handle  11  includes a boss section  13  from which a lever  14  extends. The lever  14  is formed so as to be grasped by the hand of a user. At substantially right angles to the direction to which the lever  14  extends, there is a latching tongue  15 . 
     The flap  12  (see FIG. 7) has a mounting portion  16  which incorporates a pair of stub axles  17 . The central axis of the stub axles  17  coincides with the axis of rotation  18  of the flap  12 . 
     The flap  12  is profiled so as to provide a pair of oppositely sloping faces  19 . When the flap  12  is in the release position (see FIG.  2 ), an edge of the tongue  15  lies adjacent one of the slopping surfaces  19 . As the lever  14  is rotated in the direction of arrow C (see FIG.  2 ), the tongue  15  slides across the surface  19  causing the flap  12  to pivot about the pivot axis  18  until it reaches the latching position as shown in FIG.  1 . In the latching position the tongue  15  is located on or above the surface  20  which essentially separates the two slopping surfaces  19 . 
     In a preferred form of the invention the mounting  10  is formed by a base  21  and a cover  22  (see FIGS.  5  and  6 ). The base  21  has a pair of openings  23  through which mechanical fasteners can engage to mount the base  21  to the window sash. The base  21  further has a bore  24  into which a spigot or shaft  25  forming part of and extending from tongue  15  can rotatably locate. 
     As can be seen in FIGS. 5 and 6, the lever  14  and boss  13  are integrally formed and preferably the tongue  15  is a separate component. The tongue  15  has a bore  25   a  in which engages spigot  25  of boss  13 . For angular location projections  26  of spigot  25  fit into recesses  26   a  in bore  25   a  to key the tongue with the handle. As will hereinafter be explained, a screw or like mechanical fastener  50  extends through a cam washer  34  (see FIG. 5) bore  25   a  and into a bore  28  in the spigot  25  of boss  13 . 
     The stub axles  17  of flap  12  are mounted by a shaped projection  29  extending from the main body of the flap  12 . A recess  30  is formed in base  21  within which projection  29  can engage so that the stub axles  17  can locate in a pair of opposed recesses  31  in the opposing walls at the sides of recess  30 . 
     In the preferred form a curved shoulder  32  is formed adjacent recess  31 . The curved surface  33  adjacent stub axles  17  rotatably engages with the shoulders  32 . As a result the flap  12  is mounted to the base  21  by not only the stub axles  17  but also the sliding engagement of surface  33  with shoulder  32 . 
     The projection  29  and stub axles  17  are retained in the recess  30  by cover  22  as will hereinafter be explained. 
     There is also provided a cam washer  34 . This cam washer fits in a shaped recess  35  in the underside of mounting base  21 . The cam washer  34  has a turret  35  which engages in bore  24 . The spigot  25  of tongue  15  engages in the  20  bore of turret  35 . 
     A headed fastener  50  can be inserted shank first through cam washer  34  to pass through spigot  25  and projection  26  as previously mentioned and engage in the bore  28  of boss  13  to thereby mount the cam washer  34 , tongue  15  and handle  11  to the mounting base  21 . The head of the headed fastener  50  locates in mouth  37  on the under side of cam washer  34  (see FIG.  8 ). 
     Once the handle  11 , tongue  15 , flap  12  and cam washer  34  are mounted with base  21 , the cover  22  is located on the base  21  in a snap-lock fitting. Cover  22  ensures that the flap  12  remains in its mounted position on base  21 . In a preferred form of the invention the snap fit of the cover  22  is achieved by a ledge  38  engaging under a rebate  39  of the base  21  while lips  39  clip down over the wall  40  of the base  21 . 
     The cover  22  not only retains the flap  12  in place but also adds strength to the base  21 . A further advantage is that it covers what can often be unsightly mounting screws in openings  23 . Thus with the cover in place the mounting base takes on a much cleaner aesthetically pleasing appearance than is the case was known window fasteners. 
     In a preferred arrangement, the flap  12  is an interference fit with the base  21  so as to ensure that the flap  12  is retained by the base independent of a cover. It also facilitates assembly of the flap  12  to the base  21  during assembly of the fastener. 
     The projection  29  of flap  12  carries a generally triangular follower  41  (see FIG.  7 ). This provides a pair of surfaces  42 . 
     Projecting from the side of the cam washer  34  is a cam surface  43 . As the lever  14  is moved in the direction of arrow O the cam surface  43  inter-engages with a surface  42  so that the flap  12  is driven to the unlatched position as shown in FIG.  2 . However, it will be seen from FIG. 3 that the lever  14  needs to move a distance before the cam surface  43  comes into engagement with a surface  42 . This enables the tongue  15  to move clear of the flap  12  before the inter-engaging cam  43  and surface  42  move the flap  12  to its unlatched position. 
     Disposed at the opposite side of the cam washer  34  is a nose  44 . This contacts a surface  45  of the base  21  when the handle  11  has moved to the “open” position (see FIGS.  2  and  4 ). The inter-engagement of nose  44  and surface  45  provides an end stop which determines the fully opened position of the handle  11 . 
     Adjacent cam surface  43  is a shoulder  46 . This shoulder  46  comes in contact with a surface  47  of the base  21  so that when the handle is in the fully closed position (FIGS.  1  and  3 ), an end stop is established by the contact of shoulder  46  and surface  47 . Therefore not only does the cam washer  34  provide the means of moving the flap  12  to its unlatched position, it also provides end stops which determine in conjunction with appropriately positioned stop surfaces of the base  21 , the fully opened and fully closed position of the handle  10 . 
     It will be appreciated that the handle  10  can be located at one of two positions 180° apart on the projection  26  of the tongue  15 . Thus the “hand” of the fastener can be simply selected by releasing the headed fastener holding the cam washer  34  and tongue  15  to the base  21  and moving the handle  10  so that the lever  14  projects from the required side of the tongue  15 . 
     In a preferred form of the invention the cam washer  34  is configured as are the end stop surfaces of the base  21  so that the cam washer correctly operates irrespective of whether the lever  14  is located “left” handed or “right” handed. However, the cam washer  34  as illustrated is not “non handed”. Thus when changing the hand of the handle  10  it is necessary with the illustrated form of the invention to replace the cam washer  34  with that which is correct for the required “handing” of the handle  10 . This is readily achieved as the headed fastener coupling the components together needs to be removed to enable the handle to be repositioned and during this operation the cam washer  34  can simply be replaced. 
     In the ideal configuration of the window fastener, all the components are non handed thereby meaning that the installer only needs to correctly position the handle  10  for the handing required. However, in the illustrated arrangement, the manufacturer will need to manufacture two different configurations of cam washer  34  and the installer will simply select the correct cam washer for the required handing of the fastener. 
     The present invention thus provides a fastener whereby different “hands” of handle are not required. Also by having an internal mechanism for moving the flap to the non latching position, it is not necessary for the tongue  15  to play any part in the moving of the flap to the non latched position. Consequently a projection on the flap  12  which inter-engages with the tongue  15  so as to drive the flap to the non latching position is not required. This not only results in the flap  12  not being handed but improves the aesthetic appeal of the fastener. 
     The aesthetic appeal of the fastener is also greatly enhanced by the cover which engages with the mounting base  21 . As mentioned previously, the cover also adds to the rigidity and strength of the base  21 . The need to be able to deform partially the mounting portion of the flap to fit with the mounting base as required in the fastener of EP 0133051 is therefore not required. This further leads to increased strength and retention of the flap with the mounting base  21 . Also the choice of material from which the flap can be made is increased as the need to be able to deform at least part of the flap for fitting is no longer a requirement. 
     The components of the fastener can be diecast or moulded from a suitable plastics material or a combination of plastics materials and/or diecasting. It is envisaged that in a preferred form of the invention the fastener will be manufactured by principally diecasting.