Latch device

Information

  • Patent Grant
  • 6669242
  • Patent Number
    6,669,242
  • Date Filed
    Wednesday, June 19, 2002
    23 years ago
  • Date Issued
    Tuesday, December 30, 2003
    21 years ago
Abstract
A latch device for sliding and hung window systems. The latch device has a mounting base (15) with which a pair of counter-rotatable cam elements (11) are mounted. A lever cover (12) is slidingly mounted on the base (15). The lever cover (12) is coupled to the cam element (11) so that sliding movement of the lever cover (12) causes the cam elements to counter-rotate. Each cam element (11) has a cam portion (22) which is engageable through an opening (41) in a keeper (14) to latchingly engage behind a cam engagement surface (42) associated with the opening (41).
Description




BACKGROUND OF THE INVENTION




This invention relates to a latch device.




With sliding and hung window systems it is necessary to include a latch device (sometimes referred to as a “sash lock”) to latch the window in a closed position. Over the years there have been many proposed types of window latches which aim to provide not only secure latching but also ease of operation. Despite the wide range of proposals which have been developed over the years there still exists the possibility of an improved latch device for sliding and hung window systems.




For example, with known latches for sliding and hung window systems forces can arise when the latching operation is carried out which causes the window to move off centre. This can result in sealing problems, distortion of window sash/rails, undesirable loadings applied to mounting hardware etc. These undesirable forces generated in the window generally arise from the use of a cam and keeper arrangement which is a typical latching mechanism for sliding and hung window systems.




Also there exists the need to ensure that that latching device prevents or renders difficult unauthorised access to be gained by external manipulation of the latch in order to release the latch tongue. To achieve this objective it is known to include a shroud or shield arrangement which prevents someone outside the window from engaging between, e.g. the window sashes, a thin tool to apply force to the latching tongue or cam to release it from the keeper. Such arrangements have not always been successful.




There also exists the possibility of improving the operative mechanism of such latches to not only improve the application of physical effort to operate the latch device but to additionally try and improve the aesthetic appeal of the latch. There is a move these days to have window hardware which, when visible, has a more pleasing appearance than has hitherto been thought to be necessary.




SUMMARY OF THE INVENTION




It is thus an object of the present invention to provide a latch device for sliding and hung window systems the latch device being of a construction which goes some way to achieving one or more of the above identified desired features.




Broadly, according to one aspect of the invention there is provided a latch device for sliding and hung window systems the latch device including a mounting base, a pair of counter-rotable cam elements coupled to the base, a lever cover slidingly engaged with the mounting base and a coupling mechanism which couples the lever cover to the cam elements whereupon in use a sliding movement of the lever cover is translated into pivotal movement of the cam elements.




The latch device further includes a keeper having a pair of cam engagement surfaces with which the cam elements are engagable to latch the mounting base to the keeper. Preferably the keeper includes a body having a pair of openings within each of which is located a said cam engagement surface.




Preferably the latch further includes a deadlocking means for whereby in use the cam elements can be deadlocked when in the latching position.




According to one preferred embodiment to the invention each cam element includes a follower which engages within a groove associated with the lever cover.




In a preferred form of the invention the latch device further includes detent means whereby the lever cover is releasably held in positions corresponding to the latch device being in the latching and unlatching positions.











BRIEF DESCRIPTION OF THE DRAWINGS




In the following more detailed description of the invention according to one preferred embodiment reference will be made to the accompanying drawings in which:





FIG. 1

is an exploded view of the components of the latch device,





FIG. 2

is a perspective view of the latch device in the latched position,





FIG. 3

is an underside view of

FIG. 1

,





FIG. 4

is a perspective view from essentially the opposite direction of that of

FIGS. 1 and 2

but showing the latch device in an unlatched position,





FIG. 5

is a view similar to

FIG. 3

but showing the underside of the latch device,





FIG. 6

is an underneath perspective view of the lever cover,





FIG. 7

is a detailed drawing of the latch in the latched position showing hidden detail,





FIG. 8

is a section view on line A A of

FIG. 7

, and





FIG. 9

is a view similar to

FIG. 7

but showing the latch device in the unlatched position.











DESCRIPTION OF THE PREFERRED EMBODIMENT




Referring firstly to

FIG. 1

of the drawings the various components of the latch device are shown in exploded view. The components comprise a base


10


, a pair of cam arms


11


, a lever cover


12


, a support finger


13


, and a keeper


14


. Conveniently the cam arms


11


are identical.




The base


10


(which can be formed for engineering plastic) includes a floor


15


with a pair of opposing end walls


16


.




Adjacent each end wall is a spigot


17


each of which engages within bore


18


of boss


19


of a cam arm


11


. The cam arm


11


is thus able to pivot about a pivot axis defined by the spigot


17


.




Each cam arm


11


includes an arm


20


which radiates from boss


19


. Upwardly projecting from arm


20


is a pair of pins


21


. The distal end of the arm


20


includes an upstanding cam portion


22


.




The lever cover


12


(which can be of die cast Zinc construction) includes a cover portion


23


from one side of which projects an upstand


24


. A wall


25


extends downwardly from the upstand


24


and merges into a pair of opposed end walls


26


. The upstand


24


forms a gripping portion to be gripped in or engaged by the fingers of a user.




Projecting downwardly from the underside of cover portion


23


is a pair of shaped continuous walls


27


each of which define an actuation slot


28


(see more particularly

FIGS. 6

,


7


and


9


). Into each of these actuation slots


28


engages a pin


21


of a cam arm


11


as can be seen for example in

FIGS. 7 and 9

.




Referring to

FIG. 6

there is shown a pair of spaced apart opposing L shaped walls


29


which extend from the inner surface of the wall


25


and define therebetween a slot


30


. Into this slot engages a tongue


31


which projects from a base portion


32


of support finger


13


. A pair of pins


33


which project from an edge of each of walls


29


engage in openings


34


in the base


32


.




As can be seen, for example, in

FIGS. 3 and 5

the support finger


13


when installed in the lever cover


12


is arranged so that the finger


35


projects laterally relative to wall


25


of the lever cover


12


. These Figures also show how the finger


35


engages in an elongate recess


36


in the underside of floor


15


of base


10


. The elongate recess


36


is one at one end to receive the finger


35


.




The keeper


14


is formed of a body


37


which has a centrally located mounting bore


38


. This bore


38


is formed in a spigot


39


and is accessible through a counterbore


40


in the front surface of the body


37


.




Flanking the counterbore


40


is a pair of elongate openings


41


. As can be more clearly seen in

FIGS. 1 and 9

a cam engagement surface


42


is associated with each opening


41


. The cam engagement surface


42


is of curved configuration such that it is inter-engagable with the curved cam portion


22


of the cam arm


11


. A clearance


43


is provided between cam engagement surface


42


and one long side of opening


41


.




Referring to

FIG. 6

of the drawings it will be observed that running parallel to the inside surface of end walls


26


and extending from wall


25


is a partition wall


44


. The spaced apart walls


26


and


44


thus form a track


45


into which the sidewall


16


of base


10


slidingly engages.




A tab


46


at the distal corner of wall


26


engages (see

FIGS. 3 and 5

) in a recess


47


in the underside of floor


15


of base


10


. A shoulder


48


at the end of recess


47


inter-engages with the tab


46


to form a stop which defines the end point of the movement of the lever cover


12


relative to base


10


when the latch device is in the open or unlatched position (see for example FIGS.


5


and


9


).




As can be seen in e.g.

FIG. 9

a small projection


50


is formed in the floor of the track


45


. This projection


50


can engage in respective detents


51


and


52


in the upper edge of end wall


16


of base


10


. The projection


50


engages in detent


51


when the lever cover


12


is in the open or unlatched position and in detent


52


when the lever cover


12


is in the closed or latched position.




In use of the latch device the keeper


14


is mounted by a single mechanical fastener such as a self-tapping screw engaged through bore


38


to the moving rail or fixed rail of one window sash or to a mullion or other fixture such as a portion of a fixed window frame or surround. Similarly by using suitable mechanical fasteners engaged through openings


53


in the floor


15


of base


10


the base is fitted to a rail of the movable window sash.




When the moving window sash is in the “closed” position the components of the latch device will have the relationship shown in

FIGS. 2

,


3


,


7


and


8


. To latch the window in the closed position the lever cover


12


is pushed, via pressure applied to upstand


24


, toward the keeper


14


. The resultant relative movement of lever cover to base causes the pins


21


of cam arms


11


to track along respective of the slots


28


which cause a counter-rotation of the two cam arms


11


about spigot


17


. As a result the leading edges


54


of the cam arms


11


enter into openings


41


and moves behind the cam engagement surfaces


42


. The clearances


43


adjacent curved cam receiving surfaces


42


provide a clearance for the arm


20


during such movement.




The cam portions


22


are thus moved so that the cam portions


22


fully engage behind the respective engagement surfaces


42


when the lever cover


12


has been moved to its fully closed position i.e. projections


50


engage in respective of detents


52


. This engagement can be seen in

FIGS. 2

,


3


and


7


.




Toward the end of the movement of lever cover


12


there is a degree of free motion which results in the pins


21


moving into portions


28




a


of slots


28


. Consequently, a deadlocking action occurs in respect of the cam arms


11


. This occurs because if someone wishes to gain unauthorised access through the window engages a thin object between the base


10


and keeper


14


to engage cam arm


11


a force cannot be applied to the cam arm


11


to cause it to rotate because of the location of pin


21


in portion


28




a.


The only way that the cam arm can rotate is by firstly moving the lever cover


24


so that the pins


21


become aligned with the main slotted portion


28


. At this point rotation of the cam arms


11


can commence to release the cam arms from the keeper


14


.




Because of the counter rotating cam arms


11


the action of the cam arms


11


engaging with the keeper


14


actually produces a centralising action on the window sash. Also the latch device exhibits good pull-in characteristics so that the window sash can pull onto seals at the final closed position.




Because the latch device relies on a push-pull type action applied to the lever cover


12


it is consequently easy to operate. The large gripping area formed by wall


24


allows for easy gripping in the fingers of the user so as to provide the necessary pulling action to release the latch device. Furthermore, it enables the user to pull the window to an open position. Similarly the combination of walls


24


and


25


provide a good contact area for a user to apply a pushing action to the lever cover


24


when closing and latching the window.




Because of the lost motion at the final closing of the latching device which moves the pins


21


into end portions


28




a


of slots


28


a deadlocking action on the cam arms


11


is achieved. This ensures that the latching device is secure when in the latched position and thereby resists any attempt by someone wishing to gain unauthorised access to manipulate the cam arms


11


from outside the window. The fact that the latch device employs two counter rotating latch arms


11


further ensures that unauthorised access is prevented because someone gaining access would need to simultaneously manipulate both cam arms.



Claims
  • 1. A lock device for sliding and hung window systems, the latch device including a mounting base, a pair of counter-rotatable cam elements coupled to the base, a lever cover slidingly engaged with the mounting base, a coupling mechanism which couples the lever cover to the cam elements whereupon in use a sliding movement of the lever cover is translated into pivotal movement of the cam elements, a keeper having a pair of cam engagement surfaces with which the cam elements are engageable to latch the mounting base to the keeper and a deadlocking means whereby in use the cam elements can be deadlocked when in the latching position.
  • 2. A latch device as claimed in claim 1 wherein said keeper includes a body with a pair of openings within each of which is located a said cam engagement surface.
  • 3. A latch device as claimed in claim 1 wherein each cam element includes a follower which engages with a guide associated with the lever cover.
  • 4. A latch device as claimed in claim 2 wherein the guide is a groove of substantially L-shape configured to permit the pin to slidingly move therealong.
  • 5. A latch device as claimed in claim 4 wherein the cam element includes a bore which is mounted on a spigot of the mounting base.
  • 6. A latch device as claimed in claim 5 wherein the lever cover includes a pair of tracks which are slidingly engaged with projecting walls of the mounting base.
  • 7. A latch device as claimed in claim 6 wherein the lever cover includes an upstand which forms a finger engaging portion.
  • 8. A latch device as claimed in claim 1 wherein the keeper includes a wall in which said pair of openings are formed, each opening having a first open portion which is of greater width than a second open portion, said first open portion and second open portion being connected.
  • 9. A latch device as claimed in claim 8 wherein each cam element includes an arm portion which in the latching position is at least in part engaged through the second open portion and a curved wall at a distal end of the arm portion which passes at least in part through the first open portion as the cam element moves to and from the latching position.
  • 10. A latch device as claimed in claim 9 wherein the cam engagement surface is a curved surface which curves away from an edge of the first open position adjacent the connection between the first open portion and second open portion.
  • 11. A latch device as claimed in claim 1 wherein the lever cover includes a finger which is slidingly engaged in a recess in an underside of the mounting base.
  • 12. A latch device as claimed in claim 11 wherein each cam element has a follower slidingly engaged with a guide associated with the lever cover, said guide includes a first part which extends substantially transverse to the direction of movement of the lever cover, and a second part which extends substantially in the direction of movement and into which the follower can move during a degree of free motion of the lever cover relative to the cam element when the cam element has reached the latching position.
  • 13. A latch device as claimed in claim 12 wherein the guide is a substantially L-shaped groove.
  • 14. A latch device as claimed in claim 12 wherein the keeper includes a pair of apertures through each of which at least part of a curved wall of a respective cam element can pass to engage with said cam engagement surface.
  • 15. A latch device as claimed in claim 14 wherein the aperture includes a clearance to receive at least a part of an arm portion of the cam element.
  • 16. A latch device as claimed in claim 15 wherein the arm of the cam element is pivotally mounted to the mounting base and the curved wall is located at a distance from the axis of the pivotal mounting of the arm.
  • 17. A latch device as claimed in claim 15 further including deadlocking means whereby in use the cam elements can be deadlocked when in the latching position.
  • 18. A lock device for sliding and hung window systems, the latch device including a mounting base, a pair of counter-rotatable cam elements coupled to the base, a lever cover slidingly engaged with the mounting base, a coupling mechanism which couples the lever cover to the cam elements, the coupling mechanism including a follower which engages with a guide associated with the lever cover, the follower being in the form of a pin which is spaced from a pivot axis about which the cam element is pivotally moveable whereupon in use a sliding movement of the lever cover is translated into pivotal movement of the cam elements, and a keeper having a pair of cam engagement surfaces with which the cam elements are engageable to latch the mounting base to the keeper.
Priority Claims (1)
Number Date Country Kind
512510 Jun 2001 NZ
US Referenced Citations (6)
Number Name Date Kind
857922 Campbell Jun 1907 A
2540686 Milburn Feb 1951 A
2668070 Schmitt Feb 1954 A
4554907 Overley Nov 1985 A
5171048 Weinerman Dec 1992 A
5915766 Baumeister Jun 1999 A