Information
-
Patent Grant
-
6669242
-
Patent Number
6,669,242
-
Date Filed
Wednesday, June 19, 200223 years ago
-
Date Issued
Tuesday, December 30, 200321 years ago
-
Inventors
-
Original Assignees
-
Examiners
Agents
- Blakely, Sokoloff, Taylor & Zafman
-
CPC
-
US Classifications
Field of Search
US
- 292 11
- 292 25
- 292 27
- 292 45
- 292 47
- 292 46
- 292 49
- 292 DIG 20
- 292 DIG 47
-
International Classifications
-
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)