GB2452514A - A cam lock for a window or a door - Google Patents

Abstract

A lock for a vent such as a window or a door having a cam 14 slidably a keep 10. The cam 14 is attached to a sliding bar arrangement 38 for movement into a slot 12 of the keep 10 for locking the vent in a closed condition. A secondary locking element 36 is also attached to the sliding bar arrangement 38 to move in unison with the cam 14 and has a camming member 56 laterally spaced from the cam 14 which can engage within the slot 12 for locking the vent in an ajar position. As shown the secondary locking element 36 is a C-shaped member with lateral arms 56 forming two camming members. The two arms allow left hand and right hand mounting of the lock. Alternatively a pair of secondary locking elements similar to the cam 14 and laterally spaced therefrom could be provided.

Description

The present invention relates to a lock for a window or door, i.e. a vent, and accessories for existing locks to allow the vent both to be locked more securely in a closed position, and also to allow it to be locked in an ajar or venting position, often referred to as a night venting position.

It is known in the art to provide locks by means of which a vent can be securely locked in a closed position -for example, a cam lock is one where a cam on the window (or door) engages a slot in a keep on the window frame (or door frame) for that purpose.

Similarly, it is known to provide cam locks in which that vent can be locked in an ajar or venting position for allowing room ventilation. That is achieved by providing two laterally spaced slots in the keep. One of the slots then provides for securement of the door or window in the closed position and the other slot provides for securement of the door or window in the ajar or venting position. See Figure 7 for a typical prior art keep of this type.

It is also known in the art to make these cam locks reversible, i.e. able to be fitted to either a left handed vent or a right handed vent. That is done by making the keep reversible -i.e. with two pairs of slots, each pair pointing in the opposite direction to the other. Such a keep is shown in Figure 7.

Prior art cam locks usually operate at the edges of a vent, with the keeps being positioned in the edges of the frames for them. There is a constant drive, however, often for better aesthetics, to provide thinner or narrower sections for the frames and the vents.

The keeps, however, have a minimum practical width both due to their strength requirements and due to the need for the two slots to have a useful separation between them (too narrow, and the ajar position for the vent would not serve a venting purpose).

Thus the keeps are increasingly becoming difficult to incorporate neatly or flush into the frames. it would be desirable, therefore, to provide an alternative lock arrangement for a vent that still allows for both a fully closed position and an ajar or venting position.

In accordance with the present invention there is provided a lock for a vent, comprising a cam and a keep; a sliding mechanism for providing release motion between the cam and the keep such that the cam can enter the keep and lock the vent in a first position.

wherein the lock further comprises a secondary locking element, laterally spaced from the cam and moveable with the cam for entering the keep when the cam is in a second position that is laterally spaced from the slot to lock the vent, in use, ajar.

Preferably the keep is for mounting on a frame of an opening. Preferably it comprises a slot into which the cam can fit.

The keep preferably forms a frame-side half of the lock.

Preferably the cam is attached to a sliding bar arrangement for mounting at an edge of a window or door.

Preferably the cam and sliding bar arrangement together form a vent-side, i.e. a window-side or a door-side, half of the lock.

Preferably the cam is adapted, via its attachment to the sliding bar arrangement, to move, in use, relative to the edge of the window or door, between a first position and a second position.

Preferably the cam, in use, will be positionable, via that movement, when the vent is in a closed condition, into a slot of the keep for locking the window or door in that closed condition.

Preferably the secondary locking element is also attached to the sliding bar arrangement, whereby it will also move relative to the edge of a window or door in unison with the cam whenever the cam is moved.

Preferably the secondary locking element has a further caniming member that is laterally spaced from the cam, which is also, in use, positionable within the slot, but instead of the cam, when the cam is moved from the first position into its second position, when the vent is instead in an ajar condition, thereby locking the vent ajar.

Preferably the secondary locking element comprises an L-shaped arm in section.

Preferably the L-shaped arm has a forearm with an axis extending generally parallel to, but spaced laterally from, the axis of the cam. That forearm forms the further camming member.

The upper arm of the L-shaped arm preferably runs perpendicularly between the cam and the forearm.

Preferably a second L-shaped arm is also provided, also spaced laterally from the cam, but in the opposite direction to the first L-shaped arm, and attached to the sliding bar arrangement. This provides an alternate secondary locking element, whereby the improved cam lock arrangement, like an unmodified cam lock arrangement, can still be fitted both to a left handed vent or to a right handed vent, while still offering the two lockable positions for the vent.

Preferably the two L-shaped arms are symmetrically arranged (or shaped) either side of the cam.

Preferably the two L-shaped arms together form a unitary C-shaped member.

Preferably, the or each L-shaped arm, or the unitary C-shaped member, is attached to the sliding bar arrangement between the cam and the sliding bar arrangement. This may be done using the same attachment means as used to attach the cam to the sliding bar arrangement. Thus that may be done at the original manufacturing stage, i.e. in the factory. Alternatively the or each L-shaped arm, or the unitary C-shaped member, might be attached to the sliding bar arrangement later, e.g. as an on- site or retro-fit component.

Preferably the cam is riveted to the sliding bar arrangement. Preferably the or each L-shaped arm, or the unitary C-shaped member, is then attached to the sliding bar arrangement by sandwiching it or them between the cam and the sliding bar arrangement.

Preferably the forearm of the or each L-shaped arm has a foot, or end flange, bent inwardly to form an inwardly extending flange. Another flange may be provided at the end of the cam. Those flanges can help to prevent a locked window or door from being forced open by jamming apart the cam/secondary locking element from the keep (i.e. in the cam's axial direction) -the relevant flange(s) would engage underneath the slot's rim.

The flange may also extend outwardly to further improve lock security. For example, prior art cams often have a circumferential flange, thus having a T-shaped section along its axis. Thus the forearm may similarly have a T-shaped section at its end.

Preferably the or each L-shaped arm's flange extends along substantially the whole depth of the arm. Thus it preferably has a generally rectangular shape as viewed parallel to the cam's central axis. Preferably, that rectangle's long sides run substantially parallel to the longitudinal axis of the sliding bar arrangement, i.e. in the same direction as the cam's movement between its first and second positions. That orients the flange(s) such that they will fit correctly into the slot in the keep when required to lock the vent ajar.

Preferably the further camming member locates closely adjacent a rear edge surface of the keep when both the vent is in its closed condition and the cam is in the slot, for offering a secondary lock for the cam lock arrangement. For example, the space between the flange and the rear edge surface of the keep may be about 2mm. This offers additional security to the lock.

Where two further camming members are provided, i.e. one either side of the cam, preferably the second further camming member locates closely adjacent a front edge surface of the keep when both the window or door is in its closed condition and the cam is in the slot. For example, the space between the flange and the front edge surface of the keep may be about 2mm. This offers yet additional security to the lock.

Preferably the slot is positioned midway between a flat front edge surface of the keep and a flat rear edge surface of the keep.

Preferably the open lateral spacings either side of the cam to respective further camming members are of an equal size and shape.

Preferably the or each open lateral spacing is sized such that the keep is securely retained within that spacing when in the locked-ajar position. This prevents window or door rattle in that ajar position even when the further camming member is thinner than the slot since both the cam and the camming member loosely grip the keep to restrain such rattle.

Preferably the thickness of the further camming member is no more than about half the width of the slot.

Preferably the cam is a metal element.

Preferably the secondary locking element is made of metal too, although it may be a reinforced plastic molding. Most preferably, it is either die-cast or a pressing.

Preferably the keep is formed with a generally d-shaped section, with a main 0-shaped body (in section) with an upper flange and a lower tail extending therefrom.

Preferably the upper flange and the lower tail together define a generally flat back, with the 0-shaped body extending away from it. The flat back, in use, preferably is mounted against a frame.

Preferably the slot is provided in the main 0-shaped body, on an opposite side thereof to both the upper flange and the lower tail, i.e. away from the back. That side may be generally flat faced, but with rounded edges leading to two further sides of the main o-shaped body that join to the upper flange and the lower tail.

Preferably the slot extends from one end of the keep towards the other, through its section, but not all the way through it to the other end. By having the slot terminate only past-way through the section, i.e. before the opposite end of the keep, the 0-shaped body retains significant strength and rigidity, thereby having improved resistance to bending and torsion, thus further improving lock-strength.

Two slots may be provided in the keep, one at each end of the keep (or the slot may extend the full length of the keep. Such arrangements for the keep maintain the ability for the cam lock arrangement to be reversible, i.e. useable for both right and left handed vents since the cam can engage into a slot in the keep at either end of the keep.

Preferably, however, two slots are provided, both extending from opposite ends of the keep only part way towards the middle of the keep. Preferably one slot mirrors the other.

Preferably the two slots are, straight, parallel and co-linear. They may be rounded slight open at their respective ends, however, to assist with locating either the cam or the further camming member into the slots. Thus, as the cam or the further camming member enters the slots, it pulls the vent tightly into a locked condition (either closed or ajar).

Preferably the lower tail has a tapered face. Preferably the tapered face intersects with and tapers away from the back of the keep at an acute angle. The taper defines a part dovetail for locating in a corresponding groove in the frame.

Preferably the flange has a tapered face. Preferably the tapered face intersects with and tapers away from the back of the keep at an obtuse angle. The taper facilitates the insertion of the flange into a groove on the frame.

The tail and flange allow the keep to be slidably retained on an extruded frame section.

However, a screw hole, preferably positioned between the two slots, is also provided in the keep so that a screw can be used to lock the keep in a fixed position once it has been correctly located along that section.

The present invention also provides a window or door arrangement comprising a window or door, and a frame therefor, and a cam lock arrangement as described above, the keep being mounted Onto the frame and the cam, the sliding bar arrangement and the secondary locking element being mounted onto the vent.

Preferably two keeps, two cams and two secondary locking elements are provided, one of each at both ends of the sliding bar arrangement. The vent will then have two cam locking devices, and thus further improved security.

One or more further keep, cam and secondary locking element may also be provided along or in the middle of the sliding bar arrangement for yet further added security.

The present invention will now be described in further detail, purely by way of example, with reference to the accompanying drawings in which: Figure 1 shows a perspective view of a cam lock arrangement having a secondary locking element fitted at one end of a sliding bar arrangement; Figure 2 shows an end view of the cam lock arrangement fitted to a window and window frame in a first locked condition -the closed condition; Figure 3 shows the cam lock arrangement of Figure 2 in a second locked condition -the venting condition; Figure 4 is a more detailed view of the cam lock arrangement from Figure 1; Figure 5 shows the cam and secondary locking element; Figure 6 is a reverse perspective view of the secondary locking element and cam, with the cam within a slot of the keep; Figure 7 shows a prior art keep with two pairs of slots; Figure 8 shows a prior art cam lock arrangement; and Figure 9 is a perspective view of a preferred keep for the present invention.

The following discussion will now refer just to locks for windows. However, the present invention is equally useable with locks for any vent.

Referring first of all to Figure 9, there is shown a preferred design of keep for a cam lock arrangement of the present invention. The keep 10 has two slots 12, one at either end of the keep 10, spaced apart by a central area 18. By this arrangement, a cam 14 can engage with the keep 10 from either end of the keep 10. Thus the keep 10 can be supported on a frame 16 (see Figure 2) either way up. As a result, the keep 10 allows the cam lock arrangement to work both with left handed windows and right handed windows.

At the central area 18, a hole 20 is provided. The hole is for receiving a screw or bolt, with which the keep can be secured to the frame 16.

In an alternative arrangement, there can be just a single slot.

In a further arrangement, the single slot runs continuously along the full length of the keep, thus not having the central area 18. However, that is less preferred due to the reduced rigidity and strength that such a design has compared to the preferred design, The keep 10 of Figure 9 has a d-shaped section (or b-shaped from the opposite end), as more clearly shown in Figures 2 and 6. The d-shape has a main 0-shaped body 22, an upper flange 24 and a lower tail 26 (see Figure 6).

The back of the d-shaped section is formed from the upper 24 flange and the lower tail 26.

The upper flange has a taper 28. That will assist with the insertion of the flange into a groove 30 in the frame 16. The taper defines an obtuse angle with the flat back of the keep 10.

The lower tail 26 also has a taper 32. That taper 32, however, defines an acute angle with the back of the keep 10 to give the tail 26 a half-dovetail appearance. That dovetail fits into another groove 34 in the frame 16.

By means of the flange 24 and the tail 26, the keep can slide along the length of the frame until locked in place by a screw through the hole 20. That facilitates accurate positioning of the keep since only one dimension is adjustable -the other dimensions are fixed by the grooves 30, 34.

The keep only has the one slot in each end. Thus it is narrower than prior art keeps having two slots, such as the keep of Figure 7. That reduced width allows the keep to be used in narrower window frames.

The second half of the cam lock arrangement of the present invention fits onto the window, rather than onto the frame for the window. That second half comprises a cam 14, a secondary locking element 36 and a sliding bar arrangement 38.

The sliding bar arrangement 38 is mounted into or onto an edge of the window for facing the keep 10 on the frame 16. This arrangement is shown in Figure 2. The sliding bar arrangement has a handle engagement bracket 50 for linking to a handle mechanism of the window (not shown) whereby the sliding bar arrangement can be slid along the edge of the window by operation of the handle for operating the cam lock arrangement. This mode of operation is well known and needs no further discussion.

The cam 14 is mounted to the sliding bar arrangement 38 in a known manner -with a rivet 52. Like prior art cams, the cam is shaped like a mushroom, having a stalk 40 and a head 42. The head 42 forms a concentric flange around the stalk 40.

The width of the stalk 40 is sized to fit into either slot 44 of the keep 10, and once in a slot, as shown in Figures 1, 2, 4 and 6, the cam 14 will serve to lock the window in a closed condition. See, in particular, Figure 2.

For added security, the concentric flange 42 is wider than the slot. Therefore, so that the cam can still be positioned in the slots, the slots 44 have undercuts-see Figure 9. Those undercuts define shoulders 46 onto which the concentric flange 42 will bear if the cam is attempted to be removed from the slot 12 by an axial movement of the cam 14 relative to the slot 44, rather than by sliding it out of the end of the keep.

The secondai-y locking element 36 In this embodiment, the secondary locking element 36 takes the form of a C-shaped member having a central recessed hole 54. It is fitted 36 between the cam 14 and the sliding bar arrangement 38 when assembling the cam lock arrangement by positioning the secondary locking element 36 between the cam 14 and the sliding bar arrangement 38. The rivet 52 then joins the three pieces together.

The C-shaped member, as shown most clearly in Figure 5, has two L-shaped arms 56 (in section). They extend either side of the cam 14 and feature an upper arm 58 and a forearm 60.

Each forearm 60 has a central plane that extends generally parallel to both the other plane and the axis of the cam 14, but laterally spaced therefrom with respect to the direction of sliding of the sliding bar arrangement 38. The two upper arms 58, however, are preferably co-planar, their plane extending perpendicular to the planes of the two forearms 60.

The lateral spacing between each forearm 60 and the cam's axis is greater than the radius of the cam's stalk 40. Thus there will be a space between the stalk 40 and both forearms 60. That spacing is sized to allow the cam 14 to be inserted into one of the slots 12 on the keep 10 with the two forearms locating either side of the keep. Thus the two forearms 60 will provide additional strength to the lock with the window is in a closed and locked condition.

Similarly, that lateral spacing allows the cam 14 to locate closely adjacent to, or in contact with, the outer side of the keep when one of the forearms has been located into one of the slots 12 on the keep, with the inside of the forearm locating closely adjacent to, or in contact with, the corresponding side of the slot. That prevents window rattle

II

even when the thickness of the forearm is significantly less than the width of the slot -in this example, the thickness of the forearm is less than half the width of the slot.

To put the cam locking arrangement into that alternative condition -the locked ajar condition, the sliding bar arrangement 38 is operated, e.g. by using the window handle (not shown), to retract the cam 14 out of the slot 12, i.e. to unlock the window 48. The window 48 is then slightly opened (to an ajar condition, as shown in Figure 3) and the handle is then used again to operate the sliding bar arrangement 38 to put the cam 14 back into its previous position with respect to the window 48. However, since the window 48 is now ajar, instead of closed, the cam 14 no longer aligns with the slot 12.

Instead one of the forearms 60 aligns with the slot 12. Thus that forearm 60 will engage into the slot 12, instead of the cam, to provide a locked condition for that ajar position of the window. In that locked condition the forearm 60 and the cam 14 will work together for holding the window stationary relative to the keep, i.e. without any significant window rattle.

The lateral spacing between the further camming member and the cam, therefore, is set so as to allow the forearm to be manufactured from a thinner piece of material than the diameter of the cam's stalk 40 and that does not compromise the window's solid constructional feel in its two locked conditions.

This locked ajar condition is desirable since it allows for venting of a house using the windows, for example during the night, without completely compromising house security.

Since two forearms are provided by the C-shaped member, rather than a single arm (which would also provide means for locking a window in an ajar condition), the modification of the prior art cam will not prevent the cam and sliding bar arrangement from being used on both left and right handed windows. Thus the cam lock arrangement can stiii be fitted to either a left-hand hung window or a right-hand hung window without modification.

In some embodiments, the cam 14 may be screwed or bolted onto the sliding bar arrangement 38. In those embodiments, the secondary locking element can readily be retro-fitted onto existing windows, i.e. without any need to re-machine lock components.

in addition to the forearms 60 providing a locking function against further opening (or closing) of the window by swinging the window 48 about its hinge, a locking function against axial jamming of the lock is also provided -an inwardly extending flange 62 is provided at the free ends of the forearms 60. These function like the concentric flange 42 provided for the cam 14.

Instead of the C-shaped member, second (and third) cams, like the first cam 14, but spaced laterally therefrom, may instead be provided as secondary locking elements.

The present invention has been described above purely by way of example. However, modifications in detail may be made within the scope of the invention as defined in the claims appended hereto.

Claims (27)

1. A lock for a vent, comprising a cam and a keep; a sliding mechanism for providing release motion between the cam and the keep such that the cam can enter the keep and lock the vent in a first position.

wherein the lock further comprises a secondary locking element, laterally spaced from the cam and moveable with the cam for entering the keep when the cam is in a second position that is laterally spaced from the slot to lock the vent, in use, ajar.

2. The lock of claim 1, wherein the cam is attached to a sliding bar arrangement for mounting at an edge of a vent.

3. The lock of claim 2, wherein the secondary locking element is also attached to the sliding bar arrangement, whereby it will move in unison with the cam whenever the cam is moved.

4. The lock of claim 1, claim 2 or claim 3, wherein the keep comprises a slot into which the cam can fit.

5. The lock of claim 4, wherein the cam, in use, will be positionable, via its sliding movement, when the vent is in a closed condition, into the slot of the keep for locking the vent in that closed condition.

6. The lock of claim 5, wherein the secondary locking element has a further camming member that is laterally spaced from the cam, which is also, in use, positionable within the slot, but instead of the cam, when the cam is moved from the first position into its second position with the vent instead in an ajar condition, thereby locking the vent ajar.

7. The lock of any one of the preceding claims, wherein the secondary locking element comprises an L-shaped arm in section.

8. The lock of claim 7, wherein the L-shaped arm has a forearm with an axis extending generally parallel to, but spaced laterally from, the axis of the cam.

9. The lock of claim 7 or claim 8, wherein a second L-shaped arm is also provided extending in the opposite direction to the first L-shaped arm, and attached to the sliding mechanism.

10. The lock of any one of claims 7 to 9, wherein the L-shaped arm is attached to the sliding mechanism between the cam and the sliding mechanism.

11. The lock of any one of the preceding claims, wherein the secondary locking element has an inwardly extending flange.

12. The lock of claim Ii, wherein the inwardly extending flange has a generally rectangular shape as viewed parallel to the cam's central axis.

13. The lock of claim 12, wherein that rectangle's long side runs substantially parallel to the longitudinal sliding axis of the sliding mechanism.

14. The lock of any one of the preceding claims, wherein the secondary locking element has an inside surface that locates closely adjacent a rear edge surface of the keep when both the vent is in its closed condition and the cam is in the keep.

15. The lock of any one of the preceding claims, wherein two secondary locking elements are provided, one either side of the cam, the second secondary locking element having an inside surface that locates closely adjacent a front edge surface of the keep when both the vent is in its closed condition and the cam is in the keep.

16. The lock of claim 15, wherein open lateral spacings either side of the cam to the respective inside surfaces of the secondary locking elements are of an equal size and shape.

17. The lock of any one of the preceding claims, wherein the keep has a slot positioned midway between a flat front edge surface of the keep and a flat rear edge surface of the keep.

18. The lock of any one of the preceding claims, wherein two slots are provided in the keep, one at each end of the keep, each extending only part way towards the middle of the keep.

19. The lock of any one of the preceding claims, wherein the keep is formed with a generally d-shaped section, with a main o-shaped body in section with an upper flange and a lower tail extending therefrom, the upper flange and the lower tail together defining a generally flat back, with the o-shaped body extending away from it, and with a slot provided in the main 0-shaped body, on an opposite side thereof to both the upper flange and the lower tail.

20. The lock of claim 19, wherein the lower tail has a tapered face that intersects with and tapers away from the back of the keep at an acute angle defining a part dovetail for locating in a corresponding groove in a frame for the vent.

21. The lock of claim 19 or claim 20, wherein the flange has a tapered face that intersects with and tapers away from the back of the keep at an obtuse angle for facilitating the insertion of the flange into a groove on a frame for the vent.

22. A vent arrangement comprising a window or a door and a frame therefor, and a lock according to any one of the preceding claims, the keep of the lock being mounted onto the frame and the cam, the sliding mechanism and the secondary locking element being mounted onto the window or the door.

23. The vent arrangement of claim 22, wherein two keeps, two cams and two secondary locking elements are provided, one of each at both ends of the sliding mechanism.

24. A cam lock arrangement substantially as hereinbefore described with reference to Figures 1 to 6 and 9.

25. A C-shaped secondary locking element for a cam lock arrangement for a vent, the secondary locking element being substantially as hereinbefore described with reference to Figures 1 to 6.

26. A window lock substantially as hereinbefore described with reference to Figures I to 6 and 9.

27. A door lock substantially as hereinbefore described with reference to Figures 1 to 6 and 9.