GB2493591A - Extendable and retractable bead member - Google Patents

Abstract

A sash window comprising a window frame, a window sash and a moveable elongate bead member 20 moveable from an extended to a retracted position and a mechanical biasing arrangement biasing the moveable elongate bead member towards the extended position. In the extended position the bead projects into the window opening to overlap an edge portion of the sash. The mechanical biasing arrangement comprises a projection 52 on one of the bead member or window frame and a surface 54 provided by the other of the bead member or window frame, the projection and surface abutting one another to bias the elongate bead member in the extended position. Preferably, the projection engages a slot 50 when the bead is in the retracted position. To move the bead a tool 62 may be provided to move the bead longitudinally (vertically) along the frame and into the slot. The projection may have curved edges. A locking mechanism in the form of a hook (104 Fig 8a) may lock the bead in the retracted position.

Description

A SASH WINDOW WITH A BIASSED RETRACTABLE PARTING BEAD

The present invention relates to sash windows, and in particular to sash windows incorporating a window sash which as well as sliding can also tilt, and which includes a retractable parting bead to allow for such tilting. The invention whilst particularly suited to such sash windows may however also be applicable to other, non-sash, types of windows.

Sash windows typically comprise a pair of window sashes located and supported within vertical channels in side jambs of a window frame. The window sashes are arranged to slide vertically within the window frame to allow for opening of the window. In more modern sash windows the window sashes can also be tilted out of the window frame about a horizontal axis, typically along or towards the bottom edge of the window sashes. Such tilting of the window sashes is a particularly desirable feature in that it allows easier maintenance access, in particular for cleaning of the windows, with the window sashes generally being arranged to tilt inwards. In addition such tilting and opening of both is windows provides an enlarged opening for access in the event of an emergency and/or otherwise.

In order to improve the appearance, making modem tilting sash windows more similar to traditional sash windows, as well as to provide improved security and draught exclusion, while still allowing tilting, it has been proposed in W02006/085093 to provide a tilting sash window with a retractable bead member. This bead member, or parting bead, is moveable from an extended position in which the bead projects and extends from the frame into the window opening to overlap an edge portion of the sash, to a retracted position in which the sash can then be tilted over the refracted distal end of the bead member. A biasing spring is provided to bias the bead member toward the extend position, and a selective locking arrangement is provided to selectively lock the parting bead in the retracted position. Other systems in which magnetic biasing is used are also provided.

While these arrangements provide significant improvements over previous arrangements they can still be thrther improved, in particular in relation to the biasing of the retractable bead member.

It is therefore desirable to provide an improved window arrangement which provides and improved or alternative to the existing arrangements.

According to the present invention there is provided a window comprising: a window frame defining a window opening; a window element mounted to the window frame; a moveable elongate bead member moveable from an extended position in which the bead projects and extends from the frame into the window opening to, in use, overlap an edge portion of the window element, to a retracted position; and a mechanical biasing arrangement biasing the moveable elongate bead member towards the extended position and comprising a projection, the projection being provided on one of the bead member or a part of the window frame, and further io comprising a surface, the surface being provided by the other of the bead member or a part of the window frame, the projection and the surface abutting one another to bias the elongate bead member in the extended position.

The projection and the surface may be aligned and/or oppositely face each other, particularly when the bead member is in the extended position. The projection and the surface may be staggered and/or unaligned, particularly when the bead member is in the retracted position.

The transition from the extended position to the retracted position may be provided, at least in part, by longitudinal movement of the bead member. The longitudinal movement may be accompanied by or be followed by a lateral movement away from the window opening.

The transition from the retracted position to the extended position may be provided, at least in part, by lateral movement of the bead member towards the window opening.

The lateral movement may be accompanied by or be followed by a longitudinal movement.

In the longitudinal movement, the projection may slide over the surface. In the lateral movement, a curved edge of the projection may slide over a part of the slot, preferably an edge thereof. In the lateral movement, an inclined part of the edge of the projection may slide over a part of the slot, preferably an edge thereof The surface may be provided with a slot.

The projection and the slot may be aligned and/or the projection may enter the slot, particularly when the bead member is in the retracted position.

The projection and the slot may be in mis-aligned, preferably with the projection in the slot, particularly when the bead member is in the retracted position. The projection and the slot may be aligned and then mis-aligned in transitioning to or towards the retracted position. The projection and the slot may be mis-aligned when a part of the slot, for instance the edge thereof, is received within a part of the projection, for instance a recess provided in the projection and particularly in the side of the projection. The projection may be provided with a hook, preferably by the recess.

The mis-alignment of the projection and slot may lock the bead member in position, for instance in the retracted position.

The slot may have a longitudinal extent which is greater than that of the projection.

The slot may have a width which is greater than that of the projection.

A selective locking arrangement, to selectively lock the bead member in the retracted position, may be provided.

The surface and a slot may be provided by a part of the window frame, preferably with the projection provided on the bead member.

The projection may be provided with an edge which abuts the surface in the extended position. The edge may include a planar portion, the planar portion abutting the surface in the extended position.

The projection may include a curved surface, the curved surface being provided on an edge proximal to the slot in the extended position. The projection may include a curved surface, the curved surface being provided on an edge proximal to the surface in the retracted position.

The planar portion may lead to a recess, for instance in the side edge. The planar portion may lead to a hook, for instance provided by the recess. The planar portion may lead to an inclined part, for instance between the planar portion and the recess andlor hook.

The bead member may be provided with a tool engagement location. A tool may be used to move the bead member from the extended position to the retracted position andlor from the retracted position to the extended position.

The projection may comprise a base portion and a rib extending there from. The base portion may be connected to the bead member.

A plurality of pairs of slots and projections may be provided along the length of the bead member.

The bead member may be moveable longitudinally with respect to the window frame from a first longitudinal position to a second longitudinal position, the projection and the slot being aligned and opposite one another in the first longitudinal position.

The window may comprise a sash window and the window element comprises a window sash.

The present invention will now be described by way of example only with reference to the following figures in which: Figure 1 is a schematic front perspective representation of a sash window incorporating an embodiment of the invention; Figure 2 is a schematic rear perspective representation of the sash window shown in figure 1, but with the window sashes in their tilted positions; Figures 3a, 3b and 3e are a more detailed perspective part sectional cutaway views of the window frame of the sash window shown in Figures 1 and 2, showing the retractable window beads in an extended position (Figure 3 a) being moved towards the retracted position (Figure 3b) and being moved away from the retracted position (Figure 3c); Figures 4a, 4b and 4c are lateral cross sectional views through the window frame shown in Figures 3a, 3b and 3c with the retractable window beads in an extended position (Figure 4a) and in a refracted position (Figure 4b) and returned to the extended position (Figure 4c); Figure Sa, 5b and Sc are more detailed longitudinal part cross sectional views through the window frame section shown in Figures 4a, 4b and 4c on line X-X with the retractable window beads in an extended position (Figure 5a) moving towards a refracted position (Figure Sb) and returning to the extended position (Figure Sc); and Figure 6 is a schematic more detailed part view of the top of the retractable parting bead abutting a header portion of the window frame; Figure 7 shows a jam hook design according to another embodiment of the invention and intended for mounting on a retractable window bead; Figures Sa and 8b are a more detailed perspective part sectional cutaway view of the window frame of the sash window shown in Figures 1 and 2, using the jam hook design according to the embodiment of Figure 7, and showing the retractable window beads in an extended position (Figure Sa) and being moved towards the retracted position (Figure 8b).

Referring to Figure 1, a sash window 10 comprises a window frame I and a pair of sashes 2, 4 vertically slidably located within the window frame 1. The window frame defining a window opening 5 comprises a pair of parallel spaced apart vertical side frame jamb members 6, 8, a top header frame portion 3 and window sill frame 7 portion. The sashes 2, 4 are disposed generally vertically in an overlapping arrangement with the sashes 2, 4 disposed closely adjacent to each other and in operation sliding one behind the other, generally within and/or parallel to the plane of the window frame 1. The vertical window jamb members 6, 8 each define double vertically extending main window jamb channels 12, 14, as shown more clearly in Figures 3a to 4b, for the respective sashes 2, 4.

The window jamb channels 12, 14 in each window jamb 6, 8 are disposed side by side adjacent to and along the length of the window side j ambs 6, 8 adjacent to the lateral side of the respective sashes 2, 4. The window frame 1, and window side jambs 6, 8 are typically fabricated from extnided uPVC sections which are joined together. Other materials for example metal, Aluminium, wood or GRP may however alternatively be used.

Each sash 2, 4 is engaged and supported in the window frame I by a pair of pivot bars (not shown) located towards the lower part of the sashes 2, 4. The pivot bars extend and project laterally from the sides of the sashes 2, 4. Pairs of tilt latches (not shown) for each sash 2, 4 are located towards the upper part of the sashes 2, 4 and similarly project laterally from the sides of the sashes 2, 4. The distal ends of the tilt latches and pivot bars are engaged within the respective window jamb channels 12, 14 thereby slidably locating the sashes 2, 4 within the window frame I. Counterbalance arrangements (not shown) to counterbalance the weight of the sashes 2, 4 and make vertical sliding of the sashes 2, 4 easier are mounted and located within the jamb channels 12, 14 and attach to the sashes 2, 4, and typically to the pivot bars. Specifically the pivot bars may be engaged in brake shoes slidably mounted in the window jamb channels 12, 14 and connected to the counterbalance arrangements and specifically one end of the counter balance springs. The tilt latches (not shown) are laterally retractable with respect to the sashes 2, 4 such that the distal ends of the tilt latches can be withdrawn from the window frame jamb channels 12, 14, allowing the upper part of the sashes 2, 4 to be disengaged from the window frame 1 allowing the sashes 2, 4 to be tilted and pivoted about the pivot bars and a horizontal axis through the lower edge of the sashes 2, 4 as illustrated in Figure 2, and out of the vertical plane of the window frame 1. Specifically, and as show the window sashes 2, 4 tilt inwards into the building within which the window 10 is fitted. An optional pair of tilt restrictor arm assemblies 16 for each sash 2, 4 connect and extend between the window frame jambs 6, 8 and side frames of the sashes 2, 4 to restrict and prevent excessive tilting of the sashes 2, 4 and support the sashes 2, 4 in a tilted position. With the sashes 2, 4 in such a tilted position, typically tilted inwardly into a building, the outer surface of the sashes 2, 4 and window 10 can be easily cleaned and/or other maintenance of the sashes 2, 4 and sash window 10 can more easily be carried out.

Referring now to Figure 3a and the subsequent figures, these show the window frame 1, and in particular vertical side window jambs 6, 8 in more detail. In Figure 4a the outline position 2', 4' of the respective sashes 2, 4 is however shown in phantom. Each of the windowjamb members 6, 8 also includes at least one elongate retractable bead member disposed vertically along the length of the window jambs 6, 8. In this embodiment the retractable bead member 20 comprises a single central bead member 20, disposed vertically between the vertical, in use, positions 2', 4' of the sashes 2, 4.

A retractable inner rear bead member may also optionally be disposed vertically adjacent to and behind the inside face of the inner sash 2. It will be appreciated that the terms front', rear', outer/exterior' and inner' refer to the respective intended positions of the beads and flanges when the window 10 is installed in a building, but are simply used to defme the relative positions of these beads.

The retractable bead member 20 is moveably mounted with respect to the window jamb members 6, 8 such that its moveable laterally into the window jamb 6, 8 from an extended position, as shown in Figures 3a, 3c and 4a, 4c to a retracted position as shown in Figures 3b and 4b. In addition the bead member 20 is also moveable longitudinally, in this case vertically, within the window jamb 6, 8.

More specifically the retractable bead member 20 is elongated and extends along substantially the entire length of the window jamb 6, 8. The bead 20 has a T shaped cross section and comprises a base portion 22 from the centre of which projects a rib portion 26 having a distal end and edge 28. The retractable bead 20, and in particular base portion 22 is located and retained within vertical bead channels 24 defined within the window jambs 6, 8 with the rib portion 26 projecting through an opening side of the bead channel 24 between small lip flanges 32 along the edges of the bead channel opening. The base portion 22 abuts against the rear of small lip flanges 32 to retain the bead members within the bead channels 24. The bead channel 24 is dimensioned and has a depth such that the bead 20 can be retracted and moved laterally into the channel with the bead 20 and rib S portion 26 substantially located within the channel 24 and window jamb, and the distal edge 28 of the bead 20 located proximal to the front lip flanges 32, as shown in Figures 3b and 4b. The bead channel 24 also extends slightly beyond the longitudinal end of the bead to allow the bead member 20 to also be moved longitudinally within the bead channel 24. Preferably the top of the bead channel 24 extends beyond the bead 20 so that the bead 20 can be moved vertically from a first longitudinal position in which a bottom of the bead rests on a bottom of the charnel 24, to a second longitudinal position.

In the extended projecting position the bead member 20 projects and extends laterally inwardly from the window jamb 6, 8 into the window opening 5 such that the rib portion 26 and edge 28 overlap the lateral edges of the sashes 2,4 vertically located within the window 10. In particular in the extended position the edges of outer window sash 4 are vertically slidably located and retained between the fixed outer flange 30 and one side of the central retractable bead 20. The lateral vertical edge of the inner rear sash 2 are similarly vertically slidably located and retained between the other side of the central retractable bead 20. The beads 20 in the extended position, and fixed flange 30 cover the edges of the sashes 2, 4 and more closely resemble a traditional, non-titling, sash window construction and detail, providing neater and more aesthetically pleasing appearance more in keeping and including the detail of a traditional sash window. In addition the sash 4 is more securely retained within the window frame I between and by the beads 20 and fixed flange 30. This improves the security of the window 10, making it more difficult to remove the sashes 2, 4 from the frame 1, and also more effectively covers and seals the lateral edges of the sashes 2, 4 reducing draughts between the lateral edges of the sashes 2, 4 and window jambs 6, 8. The retractable bead 20 also selectively retains the sash 4 when extended, whilst allowing tilting of the sashes 2, 4 when retracted.

In the retracted position, the retractable bead 20 is moved into the window frame 1 and jambs 6, 8 such that they no longer overlap, and are clear of, the lateral edge of the sash 2, 4. This then allows the sashes 2, 4 to be tilted, if required, out of the plane of the window frame 1 as shown in Figure 2, with edge of the sash 4, and optional tilt arm assemblies passing over the refracted beads 20, 22.

The retractable bead 20 preferably extends along the length of the window jamb 6, 8. Alternatively it may however be provided only part way along the window jamb 6, 8 and only in sections of the jamb 6, 8 and window frame 1 where the bead 20 needs to be retracted to allow tilting. Other sections along the window jamb 6, 8 may then incorporate fixed flanges. This would further improve the security, appearance and draft exclusion whilst allowing tilting of the sashes, albeit only when positioned in the region of the retractable beads 20.

As such the sash window 10 described above is generally as described in more detail in W02006/085093 which is incorporated herein by reference.

To control the position of the retractable bead 20 in the extended or retracted position, interacting slots 50 and projections 52 are provided. Pairs of slots 50 and projections 52 may be provided disposed at spaced apart positions along the length of the is liner 54 and the base portion 22 of the bead 20.

The slots 50 and projections 52 are provided such that in the extended and first longitudinal position of the bead 20 the slot 50 and the projection 52 are longitudinally spaced from one another by a separation 56; Figure 3a. In the extended position, the edge 58 of the projection 50 abuts the opposing surface 60 of the liner 54, This physical interaction maintains the retractable bead member 20 in the extended position, such that it extends out of the channel 24 and into the window opening 5 such that the rib portion 26 and edge 28 overlap the lateral edges of the sashes 2,4 vertically located within the window 10.

To move the bead member 20 from the extended position into the retracted position, a tool 62 is used. The tool 62 has a handle portion 64 and a distal engaging portion 66 which is inserted into a hole 68 in the rib portion 26 of the retractable bead member 20. Upward movement of the tool 62 moves the bead member 20 upward and so reduces the separation 56 until the projection 52 is able to enter the slot 50 in the liner 54; Figure 3b. Once the refracted position is reached, the rib portion 26 no longer extends into the window opening 5.

As an alternative, a button element by which a user can hold and move the beads directly without the use of a tool could be provided.

To return the bead member 20 from the retracted position (Figure 3b) to the extended position (Figure 3c), the tool 62 is moved downward, arrows of Figure 3c. The abutment of the curved side edge 70 with the side 72 of the slot 50 causes the bead member to move outward and transition into the extended position (Figure 3c), The tool 62 can S also be used to, or to assist in, pulling the bead member 20 into the extended position.

Once the edge 58 of the projection 52 abuts the opposing surface 60 of the liner 54 the extended position is reached. Further downward movement of the bead member 20 does not cause it to extend any further. However, in that extended position it once again extends out of the channel 24 and into the window opening 5 such that the rib portion 26 and edge 28 overlap the lateral edges of the sashes 2,4 vdtically located within the window 10.

Figure 4a, 4b and 4e provide alternative views of the same extended, retracted and extended positions in cross-sectional plan view.

Figures 5a, Sb and Sc show alternative view of the same extended, retracted and extended positions in side cross-sectional view.

The top of the bead channel 24, window jambs 6, 8 and header portion 3 of the window frame 1, and retractable beads 20 are preferably configured to hold and locate the bead 20 in the fir st longitudinal position. This ensures that the slot 50 and projection 52 have a separation 56 from one another and hence the extended position is maintained. This ensures that the projection 52 and the liner 60 abut to generate the biasing force.

For example, as shown in Figure 6 the top header 3 (and/or a separate fixed top bead) of the window frame I is arranged such that a top end 11 of the retractable bead 20 abut against a lower inner edge 13 of the top header 3 when the bead 20 is in the first longitudinal and extend position. Similarly although not shown bottom end of the bead 20 abuts against the bottom sill 7 of the window frame. As mentioned above the top of the bead channel 24, window j ambs 6,8 and header portion 3 of the window frame 1, and the retractable bead 20 are however also configured to allow for such upward movement of the retractable bead 20. Accordingly the top header 3 (and/or top bead) however terminates at the front walls 32 of bead channel 24 such that the bead channel 24 extends vertically beyond the lower edge 13 of the header 3 and into the top header 3 and the side frame 6, 8.

The bead 20 and more specifically end of the bead 11 can then be pushed back into the channel and slid and moved longitudinally vertically upwards with the end II of the bead going into this extended portion of the channel 24, allowing the bead 20 to be moved in to the second longitudinal position and to be retracted. In the second longitudinal position, the separation 56 has gone and the slot 50 and projection are able to cooperate with one another and so provide the retracted position. To assist in this and allow the end 11 of the bead 20 to pass over the end of the top edge 13 of the header 3 the corner of the top edge of the bead 20 may include a chamfer and/or slight radius (not shown).

The physical biasing of the bead member 20 in this way avoids the need to use expensive and limited force magnetic biasing of the bead member 20, used in a previous arrangement of the applicant, and avoids the need to provide and fit separate biasing springs, as used on other previous arrangements of the applicant, which can be difficult to fit in place, and may in use become dislodged in use.

In the further embodiment of the invention illustrated in Figures 7, 8a and 8b, a modified form of the projection 52 of the earlier embodiment is employed. The projection 52 is modified in having a lower edge 100, which is parallel to the base of the bead 20, and an inclined part 102. The projection 52 is further modified by having a recess 104, which can be thought of as a hook, provided in the side of the projection 52. This is the lower side of the projection 52 in the orientation of use. The recess 104 is sufficiently wide, dimension W, to be able to accommodate the thickness of the liner 54 that the slot 50 is provided in. The recess 104 has sufficient depth, dimension D, to be able to provide a reliable engagement between the projection 52 and the liner 54.

Once again, the position of the retractable bead 20 in the extended (Figure 8a) or retracted (Figure Sb) position is controlled by the interacting slots 50 and projections 52.

Pairs of slots 50 and projections 52 may be provided disposed at spaced apart positions along the length of the liner 54 and the base portion 22 of the bead 20.

The slots 50 and projections 52 are provided such that in the extended and fir st longitudinal position of the bead 20, the slot 50 and the projection 52 arc longitudinally spaced from one another by a separation 56; Figure 8a. In the extended position, the lower edge 100 of the projection 50 abuts the opposing surface 60 of the liner 54. This physical interaction maintains the retractable bead member 20 in the extended position, such that it extends out of the channel 24 and into the window opening 5 such that the rib portion 26 and edge 28 overlap the lateral edges of the sashes 2,4 vertically located within the window 10.

II

Once again, to move the bead member 20 from the extended position into the retracted position, a tool 62 is used. The tool 62 has a handle portion 64 and a distal engaging portion 66 which is inserted into a hole 68 in the rib portion 26 of the retractable bead member 20. Upward movement of the tool 62 moves the bead member 20 upward and so reduces the separation 56 until the projection 52 starts to overlap with the slot 50.

As the inclined part 102 of the lower edge 100 reaches the slot 50, the projection 52 starts to enter the slot 50 in the liner 54. Once the retracted position is reached, Figure 8b, the rib portion 26 no longer extends into the window opening 5.

In this embodiment, once the projection 52 is in the slot 50, it is possible to reverse the direction of the movement of the bead member 20 such that the edge 108 of the slot 50 engages with recess 104 in the side of the projection 52. This engagement helps maintain the projection 52 and hence the bead 20 in the retracted position. The engagement is easily reversible.

As an alternative, a button element by which a user can hold and move the beads 20 directly without the use of a tool could be provided.

To return the bead member 20 from the retracted position (Figure 8b) to the extended position (Figure 8a), the tool 62 may be moved upward to disengage the recess 104 from the edge 108 of the slot 50. Once the recess 104 has been disengaged, the projection 52 can move out of the slot 50. The tool 62 is then moved downward. Once the edge 102 of the projection 52 abuts the opposing surface 60 of the liner 54 the extended position is reached. Further downward movement of the bead member 20 does not cause it to extend any further. However, in that extended position it once again extends out of the channel 24 and into the window opening 5 such that the rib portion 26 and edge 28 overlap the lateral edges of the sashes 2,4 vertically located within the window 10.

It will also be appreciated that whilst the invention has been described and illustrated in relation to a window with two sliding sashes in other embodiments there may be further sashes similarly arranged in the window frame. Alternatively the window may comprise a single sliding sash and a fixed sash or window pane fixed within the window frame. In addition whilst the retractable beads are shown incorporated in the side window jambs 6, 8 of the window frame 1, they may additionally be incorporated in other frame members, for example the upper and lower frame parts. The sashes 2, 4 also, whilst typically sliding vertically may alternatively slide horizontally, and tilt about a vertical axis. hi such an arrangement the top and bottom frame members would include the retractable beads to allow tilting. Furthermore whilst the invention is particularly suited and directed to a sash type window, and this is the preferred use, the invention, and use of retractable beads projecting from a window frame to overlap the edges of a window element or pane could be used in other types of window. For example such retractable beads could be incorporated in the window frame of a conventional tilting window in which case the beads would be refracted to similarly allow tilting of the window. Indeed retractable beads could also be used in the frame of a fixed window in order to simply and more conveniently secure the actual window pane within the frame. In such a case the io retracting of the beads would allow easier installation and replacement as well as allowing for emergency removal of the normally fixed window pane to provide an emergency exit.

Various other modifications and alternative embodiments of the invention will also be apparent to those skilled in the art.

The principle and mode of operation of this invention have been explained and illustrated in its preferred embodiment. However, it must be understood that this invention may be practiced otherwise than as specifically explained and illustrated without departing from its scope as defined in the accompanying claims.

Claims (1)

1. <claim-text>CLAIMS1. A window comprising: a window frame defining a window opening; a window element mounted to the window frame; a moveable elongate bead member moveable from an extended position in which the bead projects and extends from the frame into the window opening to, in use, overlap an edge portion of the window element, to a retracted position; and a mechanical biasing arrangement biasing the moveable elongate bead member towards the extended position and comprising a projection, the projection being provided on one of the bead member or a part of the window frame, and further comprising a surface, the surface being provided by the other of the bead member or a part of the window frame, the projection and the surface abutting one another to bias the elongate bead member in the extended position.</claim-text> <claim-text>2. A window as claimed in claim I in which the projection and the surface are aligned and oppositely face each other when the bead member is in the extended position.</claim-text> <claim-text>3. A window as claimed in claim 1 or 2 in which the projection and the surface are staggered and unaligned when the bead member is in the retracted position.</claim-text> <claim-text>4. A window as claimed in any preceding claim in which the surface is provided with a slot.</claim-text> <claim-text>5. A window as claimed in claim 4 in which the projection and the slot are aligned and the projection enters the slot when the bead member is in the retracted position.</claim-text> <claim-text>6, A window as claimed in any preceding claim further comprising a selective locking arrangement to selectively lock the bead member in the retracted position.</claim-text> <claim-text>7. A window as claimed in any preceding claim in which the surface and a slot are provided by a part of the window frame and the projection is provided on the bead member.</claim-text> <claim-text>8. A window as claimed in any preceding claim in which the projection has an edge which abuts the surface in the extended position 9. A window as claimed in claim 8 in which the edge includes a planar portion, the planar portion abutting the surface in the extended position.10. A window as claimed in any preceding claim in which the projection includes a curved surface, the curved surface being provided on an edge proximal to the slot in the extended position.11. A window as claimed in any preceding claim in which the projection includes a curved surface, the curved surface being provided on an edge proximal to the surface in the retracted position.12. A window as claimed in any preceding claim in which the projection and the slot are aligned and then mis-aligned in transitioning to or towards the refracted position 13. A window as claimed in any preceding claim in which the projection and the slot are mis-aligned when a part of the slot is received within a part of the projection.14. A window as claimed in claim 13 in which the part of the slot is an edge thereof and the part of the projection is a recess provided in the projection.15. A window as claimed in any preceding claim in which the projection is provided with ahook.16. A window according to claim 15 in which the hook engages the surface in at least the retracted position.17. A window as claimed in any preceding claim in which a bead member is provided S with a tool engagement location or a button.18. A window as claimed in claim 17 in which a tool or button is used to move the bead member from the extended position to the retracted position and/or from the refracted position to the extended position.19. A window as claimed in any preceding claim in which the projection comprises a base portion and a rib extending there from.20. A window as claimed in claim 19 in which the base portion is connected to the bead member.21. A window as claimed in any preceding claim in which the longitudinal extend of the slot is greater than the longitudinal extent of the projection.22. A window as claimed in any preceding claim in which the bead member is moveable longitudinally with respect to the window frame from a first longitudinal position to a second longitudinal position, the projection and the slot being aligned and opposite one another in the first longitudinal position.23. A window as claimed in any preceding claim in which the window comprises a sash window and the window element comprises a window sash.24. A window substantially as hereiribefore described with reference to, and!or as shown in any one or more of Figures 1 to 8b.</claim-text>