Sash and case windows with secondary glazing

Abstract

A method of installing a secondary glazing panel 40 in a sash and case window 10. The panel comprises at least one sheet of glazing material 44 and a support assembly 42 which has first and second rig

Description

The present invention relates to a method of installing a secondary glazing panel in a sash and case window. The present invention also relates to a sash and case window comprising a secondary glazing panel. Background Art A sash and case window typically comprises an upper framed glazing panel, a lower framed glazing panel, and a case. Each of the upper and lower framed glazing panels constitutes a sash of the sash and case window. The case defines channels in which edges of the two sashes are received. The sash and case window is opened and closed by sliding at least one of the sashes up and down in the channels defined by the case. The sash and case window further comprises parting bead and staff bead. The parting bead comprises a length of parting bead extending between the top and the bottom of the case on each of the left- and right-hand sides of the case. The two lengths of parting bead extend from the case between the two sashes to thereby provide a weatherproof seal. The staff bead is fixed to the case around the interior side of the sash and case window and such that it extends over the periphery of the sashes whereby the staff bead retains one of the sashes, and usually the lower sash, in place in the case. Often, one of the left hand portion of the staff bead and the right hand portion of the staff bead is removably attached to the case to allow the adjacent sash to be rotated inwards when the portion of staff bead has been removed to thereby allow for cleaning of the glass of the sashes. It is known to fit a secondary glazing panel to the interior side of a sash and case window to reduce heat loss and sound transmission through the window and also, at times, to improve upon security. A first known approach involves attaching the secondary glazing panel to the case by way of a magnetic strip. A second known approach involves attaching the secondary glazing panel to the staff bead of the case by way of mechanical fixings such as screws or nails. The present inventor has recognised the above described approaches to fitting a secondary glazing panel to the interior side of a sash and case window to have shortcomings. The first known approach is often unsuited to holding a heavier secondary glazing panel in place. Furthermore, magnets lose their magnetism over time. The second approach is more suited than the first approach to holding a heavier secondary glazing panel in place. However, mechanical fixing can damage the staff bead which, aside from being generally undesirable, may compromise the staff bead’s ability to retain the sash in place. Furthermore, the presence of the secondary glazing panel may impede proper operation of the sash and case window. For example, and where the sash and case window comprises first and second shutters which are each rotatable about a respective vertical axis to close over respective left and right and interior sides of the sashes, the secondary glazing panel may obstruct full closure of the first and second shutters over the sashes. The present invention has been devised in light of the inventor’s appreciation of the above-mentioned shortcomings. It is therefore an object for the present invention to provide an improved method of installing a secondary glazing panel in a sash and case window. It is a further object for the present invention to provide a sash and case window comprising an improved secondary glazing panel. Statement of Invention According to a first aspect of the present invention there is provided a method of installing a secondary glazing panel in a sash and case window, the secondary glazing panel comprising at least one sheet of glazing material and a support assembly, the support assembly comprising first and second rigid vertical support members which each support a respective edge of the at least one sheet of glazing material, the method comprising: removing vertical staff bead of the sash and case window from an interior side of the sash and case window; positioning the secondary glazing panel on the interior side of the sash and case window such that the first and second rigid vertical support members of the secondary glazing panel are located in place of the removed vertical staff bead; and fastening the secondary glazing panel to the case of the sash and case widow whereby the support assembly of the secondary glazing panel retains one of the sashes of the sash and case window in the case. As described above, the staff bead of a sash and case window is fixed to the case around the interior side of the sash and case window and such that it extends over the periphery of the sashes whereby the staff bead retains one of the sashes, and usually the lower sash, in place in the case. According to the present invention, the vertical staff bead of the sash and case window at left- and right-hand sides is removed from the sash and case window. Removal may involve removal of nails or screws which attach the vertical staff bead to the case of the sash and case window. Then, the secondary glazing panel, which comprises at least one sheet of glazing material and a support assembly comprising first and second rigid vertical support members which each support a respective edge of the at least one sheet of glazing material, is positioned on the interior side of the sash and case window such that the first and second rigid vertical support members are located in place of the removed vertical staff bead. When the secondary glazing panel has been so positioned, the secondary glazing panel is attached to the case of the sash and case widow whereby the first and second rigid vertical support members of the secondary glazing panel retain one of the sashes of the sash and case window in the case instead of this being accomplished by the now removed vertical staff bead. More specifically, the first and second rigid vertical support members may present a barrier to movement of the sash to thereby retain the sash in the case. The sash may be sandwiched between the first and second rigid vertical support members and the parting bead of the sash and case window. The secondary glazing panel may be attached to the case by way of at least one removable fixing, such as screws. Removable fixing may allow for ease of removal of the secondary glazing panel from the sash and case window. The method according to the invention is typically practiced when the sash and case window is in situ, i.e. when the sash and case window forms part of a building. The method of installing a secondary glazing panel according to the invention may provide a more secure and perhaps also longer lasting means of fitting a secondary glazing panel to a sash and case window than the first known approach described above. Aside from this, the method of installing a secondary glazing panel according to the invention removes the risk according to the second known approach of damage being caused to the staff bead such that the staff bead’s ability to retain the sash in place is compromised. Instead, the first and second rigid vertical support members of the secondary glazing panel are located in place of the removed vertical staff bead with the first and second rigid vertical support members of the secondary glazing panel retaining the sash in place. The first and second rigid vertical support members of the secondary glazing panel may extend in a first direction orthogonal to a plane of the at least one sheet of glazing material of the secondary glazing panel. The first direction may therefore extend in a direction from an exterior of the sash and case window to the interior of the sash and case window. Furthermore, the first and second rigid vertical support members may extend in the first direction such that their extremities do not abut against a shutter before the shutter has been closed properly over the sash and case window. The method of installing a secondary glazing panel according to the invention may thus present less impediment and perhaps substantially no impediment to proper closing of shutters. A dimension of the first and second rigid vertical support members of the secondary glazing panel in the first direction may be no more than a dimension of the vertical staff bead in the first direction. The first and second rigid vertical support members of the secondary glazing panel may therefore extend no further in the first direction than the vertical staff bead whereby substantially no impediment is presented by the first and second rigid vertical support members to proper closing of shutters. Where there is clearance between the vertical staff bead to be removed and a closed shutter, there may be room for the dimension of the first and second rigid vertical support members in the first direction to be greater than the dimension of the vertical staff bead in the first direction without proper closing of shutters being impeded. A dimension of each of the first and second rigid vertical support members of the secondary glazing panel in the first direction may be such that when the secondary glazing panel is installed, the first and second rigid vertical support members face and are adjacent the frame, i.e. the sash frame, of one of the sashes. Fractional separation between the first and second rigid vertical support members and the adjacent sash frame may be desirable to, on the one hand, provide a sufficient seal and, on the other hand, provide for comparative ease of upward and downward movement of the sash in the case and relative to the first and second rigid vertical support members. The secondary glazing panel may have the form of a kit of parts comprising the first and second rigid vertical support members and the at least one sheet of glazing material, the at least one sheet of glazing material being brought into engagement with each of the first and second rigid vertical support members during installation of the secondary glazing panel. Alternatively, the secondary glazing panel may be unitary. The secondary glazing panel may therefore not comprise separate parts which are installed separately, although a part thereof may move relative to another part. The secondary glazing panel may comprise a seal which extends from each of the first and second rigid vertical support members of the secondary glazing panel. The seal may be mounted on each of the first and second rigid vertical support members such that it abuts against a part of the sash and case window remaining after removal of the vertical staff bead. More specifically the seal may be mounted so as to extend from a surface of each of the first and second rigid vertical support members in a direction parallel to a plane of the at least one sheet of glazing material and away from the at least one sheet of glazing material. When the secondary glazing panel is positioned on the interior side of the sash and case window, the seal may abut against the case. The seal may provide for improved thermal insulation and / or reduced noise transmission. The seal may be formed at least in part of resilient material. A dimension of the secondary glazing panel with the seal in place may be smaller than a respective dimension of the case of the sash and case window whereby the seal is compressed when the secondary glazing panel is positioned within the case on the interior side of the sash and case window. As mentioned above, the seal may be formed at least in part of resilient material. Furthermore, the seal may be formed at least in part of soft material. The seal may be formed from rubber, silicone, nylon brush, or the like. Each of the first and second rigid vertical support members may define a channel for accommodating the respective at least one sheet of glazing material. The channel may be substantially rectangular in cross section and of a width whereby an edge of the sheet of glazing material is a snug fit in the channel. In a first embodiment, the secondary glazing panel may comprise only one sheet of glazing material. The one sheet of glazing material may be of a height and a width such that a space defined by the case on the interior side of the case of the sash and case window after removal of the vertical staff bead is substantially filled by the one sheet of glazing material and the first and second rigid vertical support members. In a second embodiment, the secondary glazing panel may comprise first and second sheets of glazing material which are supported by the first and second rigid vertical support members such that they close different parts of the space defined between the first and second rigid vertical support members. More specifically, the first and second sheets of glazing material may be supported by the first and second rigid vertical support members such that the first sheet of glazing material closes an upper part of the space defined between the first and second rigid vertical support members and the second sheet of glazing material closes a lower part of the space defined between the first and second rigid vertical support members. The first and second sheets of glazing material may be of substantially the same height and width. In a first form of the second embodiment, at least one of the first and second sheets of glazing material may be supported by the support assembly for movement in the support assembly and relative to the other sheet of glazing material to increase or reduce an extent of overlap of the first and second sheets of glazing material. The secondary glazing panel may be configured for movement of the sheet of glazing material in an upward and downward direction. Furthermore, each of the first and second rigid vertical support members may define first and second channels which are spaced apart from each other in the first direction, i.e. in a direction from the exterior of the sash and case window to the interior of the sash and case window, each of the first and second channels extending vertically along its length, and each of the first and second sheets of glazing material accommodated in a respective one of the first and second channels. Furthermore, the first channel may be closer to the sashes of the sash and case window than the second channel, an upper one of the first and second sheets of glazing material accommodated in the first channel, and a lower one of the first and second sheets of glazing material accommodated in the second channel. At least one of the first and second channels may be of greater extent along its length in a vertical direction, i.e. in a direction between a top and a bottom of the frame, than the respective sheet of glazing material whereby the respective sheet of glazing material is movable upwards and downwards in the support assembly. Furthermore, at least one of the first and second channels may extend from adjacent a top of the respective one of the first and second rigid vertical support members to adjacent a bottom of the vertical support member whereby at least one of the first and second sheets of glazing material is movable from the top of the first and second rigid vertical support members to the bottom of the first and second rigid vertical support members and vice-versa. More specifically, each of the first and second channels may extend from adjacent the top to adjacent the bottom of the respective first and second rigid vertical support members whereby each of the first and second sheets of glazing material is movable upwards and downwards. Each of the first and second sheets of glazing material may be a tight fit in the respective one of the first and second channels, the fit being sufficiently tight that the sheet of glazing material does not move downwards in the channel under effect of gravity whilst allowing a user to apply less than undue force to move the sheet of glazing material upwards and downwards in the channel. Where the fit is insufficiently tight to hold the sheet of glazing material in the channel despite the effect of gravity, the sash and case window arrangement may comprise a locking mechanism to hold the sheet of glazing material in the channel. The locking mechanism or part thereof may be movable between an unlocked position and a locked position. In the locked position the locking mechanism or part thereof may abut against the sheet of glazing material and more specifically may press against the sheet of glazing material such that the sheet of glazing material is urged against one side of its channel. In the unlocked position the locking mechanism or part thereof may be spaced apart from the sheet of glazing material. The locking mechanism or part thereof may rotate between the unlocked and locked positions. The locking mechanism may comprise a lock support member and a rotatable member which are rotatably coupled to each other, the rotatable member rotating relative to the lock support member to provide for rotation between the unlocked and locked positions. The lock support member may be mounted on a vertical support member and more specifically may be mounted on the vertical support member between the first and second channels. The sash and case window arrangement may comprise a glazing sheet seal which is mounted to extend along its length between the first and second vertical support members. The glazing sheet seal may be mounted on one or other of the secondary glazing panel and the sash and case window to provide a seal between the secondary glazing panel and the sash and case window. The glazing sheet seal may be mounted on one, other or both of the top and bottom of the secondary glazing panel of the sash and case window. Alternatively or in addition, a glazing sheet seal may be mounted on the secondary glazing panel to provide a seal between the first and second sheets of glazing material. The glazing sheet seal may be configured, such as in respect of dimensions and material, to maintain the seal between the first and second sheets of glazing material despite relative movement of the first and second sheets of glazing material. The glazing sheet seal may be mounted on one of the first and second sheets of glazing material. More specifically, the glazing sheet seal may be mounted in a recess defined in one of the first and second sheets of glazing material. In a second form of the second embodiment, at least one of the first and second sheets of glazing material may be supported by the support assembly for rotation relative to the support assembly, such as by way of a pair of pivot hinges. Each at least one of the first and second sheets of glazing material may be supported for rotation of the respective sheet of glazing material about a horizontal axis of rotation, i.e. an axis that extends across a width of the secondary glazing panel whereby the axis is in a direction orthogonal to the first direction and orthogonal to a direction between a top and a bottom of the sash and case window. More specifically, the secondary glazing panel may comprise a main support assembly and a first subsidiary glazing panel. The main support assembly may comprise the first and second rigid vertical support members. In certain embodiments the first subsidiary glazing panel may be constituted by the first sheet of glazing material such that the first subsidiary glazing panel lacks a subsidiary support assembly. The first sheet of glazing material per se may be mounted on the main support assembly. The first sheet of glazing material per se may be removably mounted on the main support assembly. The first sheet of glazing material may be removably mounted by way of a separable pivot hinge, the first sheet of glazing material defining first and second hinge pins which each extend from a respective edge located towards an upper corner of the first sheet of glazing material. The main support assembly may define first and second grooves which are shaped to receive the first and second hinge pins respectively to allow for attachment and conversely detachment of the first sheet of glazing material. When the first and second hinge pins are properly received in their respective first and second grooves, the first and second hinge pins and the first and second grooves may cooperate to allow for rotation of the first sheet of glazing material relative to the main support assembly. The secondary glazing panel may further comprise a second subsidiary glazing panel. The second subsidiary glazing panel may be constituted by the second sheet of glazing material such that the second subsidiary glazing panel lacks a subsidiary support assembly. The second subsidiary glazing panel may comprise one or more features of the first subsidiary glazing panel described in the immediately preceding paragraph. In other embodiments the first subsidiary glazing panel may comprise a first subsidiary support assembly and the first sheet of glazing material. The first subsidiary support assembly may comprise first and second rigid vertical subsidiary support members. The first support assembly may support edges of the first sheet of glazing material, such as in a channel of the form described above in respect of the first and second rigid vertical support members and which is defined by each of the first and second rigid vertical subsidiary support members. The main support assembly may be fastened to the case of the sash and case widow, as described above. Furthermore, the first subsidiary glazing panel may be rotatably mounted on the main support assembly whereby the first subsidiary glazing panel may be rotated about the axis of rotation and more specifically a horizontal axis of rotation. The main support assembly may be shaped when installed to define a space for receiving the first subsidiary glazing panel when the first subsidiary glazing panel is in registration with the main support assembly, i.e. when the first subsidiary glazing panel has not been opened by rotation relative to the main support assembly. Furthermore, each of the first and second rigid vertical support members may be L-shaped in cross-section, the first and second rigid vertical subsidiary support members nestling in the respective L-shapes when the first subsidiary glazing panel is in registration with the main support assembly. One leg of the L-shape may face the case of the sash and case window and the other leg of the L-shape may face a sash of the sash and case window. The secondary glazing panel may comprise a glazing panel frame seal mounted on each of: one of the first rigid vertical support member and the first rigid vertical subsidiary support member; and one of the second rigid vertical support member and the second rigid vertical subsidiary support member, one glazing panel frame seal disposed such that the seal abuts against the other of the first rigid vertical support member and the first rigid vertical subsidiary support member, and the other glazing panel frame seal disposed such that the seal abuts against the other of the second rigid vertical support member and the second rigid vertical subsidiary support member. The glazing panel frame seals may thus form a seal between the main support assembly and the first subsidiary glazing panel when the first subsidiary glazing panel is in registration with the main support assembly. The first subsidiary glazing panel may be separable from the main support assembly. The first subsidiary glazing panel may be separated from the main support assembly for replacement in case of damage or wear or for ease of cleaning of the sheet of glazing material of the first subsidiary glazing panel. The first subsidiary glazing panel may be separable from the main support assembly by way of a user operable retention mechanism that allows for separation of the first subsidiary glazing panel upon user operation and that otherwise attaches the first subsidiary glazing panel to the main support assembly. Where the secondary glazing panel comprises a pair of pivot hinges for rotation of the first subsidiary glazing panel, each pivot hinge may comprise a retention mechanism. The retention mechanism may comprise a groove which is shaped to receive a pin of the pivot hinge, the groove describing a path which provides for retention of the secondary glazing panel in the main support assembly. The groove may describe an upwardly oblique path whereby the pin rests at the end of the groove under force of gravity. A user may remove the secondary glazing panel from the main support assembly by lifting the secondary glazing panel upwards against force of gravity and such that the pin travels obliquely downwards along the groove until the pin leaves the groove. The pin may extend from a rigid vertical support member of the main support assembly and the groove may be defined by a subsidiary glazing panel and more specifically a rigid vertical subsidiary support member of the subsidiary glazing panel. The secondary glazing panel may further comprise a second subsidiary glazing panel. The second subsidiary glazing panel may comprise a second subsidiary support assembly and the second sheet of glazing material. The second subsidiary support assembly may comprise first and second rigid vertical subsidiary support members. The second support assembly may support edges, and more specifically left-hand and right-hand edges, of the second sheet of glazing material, such as in a channel of the form described above which is defined by each of the first and second rigid vertical subsidiary support members. The second subsidiary glazing panel may be rotatably mounted on the main support assembly whereby the second subsidiary glazing panel may be rotated about an axis of rotation spaced apart from the axis of rotation about which the first subsidiary glazing panel frame. The main support assembly may be shaped to define a space for receiving the second subsidiary glazing panel as described above with reference to the first subsidiary glazing panel. Alternatively or in addition, the secondary glazing panel may comprise a glazing panel frame seal mounted on each of: one of the first rigid vertical support member and the first rigid vertical subsidiary support member of the second subsidiary glazing panel; and one of the second rigid vertical support member and the second rigid vertical subsidiary support member of the second subsidiary glazing panel, one glazing panel frame seal disposed such that the seal abuts against the other of the first rigid vertical support member and the first rigid vertical subsidiary support member of the second subsidiary glazing panel, and the other glazing panel frame seal disposed such that the seal abuts against the other of the second rigid vertical support member and the second rigid vertical subsidiary support member of the second subsidiary glazing panel. Further features of the second subsidiary glazing panel are as described above with reference to the first subsidiary glazing panel. Hitherto the method has involved removal of vertical staff bead, i.e. the strip of staff bead on the left-hand side of the sash and case window and the strip of staff bead on the right hand-side of the sash and case window. In further embodiments horizontal staff bead may be removed from the sash and case window. The removed horizontal staff bead may include at least one of: the strip of staff bead at the top of the sash and case window; and the strip of staff bead at the bottom of the sash and case window. In such embodiments the support assembly may comprise at least one of third and fourth rigid horizontal support members, the third rigid horizontal support member supporting an upper edge of the at least one sheet of glazing material and the fourth rigid horizontal support member supporting a lower edge of the at least one sheet of glazing material. When the secondary glazing panel is installed, each of the third and fourth rigid horizontal support members may replace the corresponding length of removed horizontal staff bead. The support assembly may comprise the third and the fourth rigid horizontal support members. The first and second rigid vertical support members and the third and the fourth rigid horizontal support members may constitute a main glazing panel frame which extends around the at least one sheet of glazing material. The main glazing panel frame may therefore comprise the first and second vertical support members which are joined to each other at their respective ends by the third and fourth rigid horizontal support members. The main glazing panel frame may be rectangular. In further embodiments the first subsidiary support assembly may further comprise third and fourth rigid horizontal subsidiary support members. The third and fourth rigid horizontal subsidiary support members may support edges, and more specifically upper and lower edges, of the first sheet of glazing material, such as in a channel of the form described above in respect of the first and second rigid horizontal subsidiary support members. The third and fourth rigid horizontal subsidiary support members and the first and second rigid vertical subsidiary support members may define a frame which extends around the first sheet of glazing material. The second subsidiary support assembly may further comprise third and fourth rigid horizontal subsidiary support members. The third and fourth rigid horizontal subsidiary support members may support edges, and more specifically upper and lower edges, of the second sheet of glazing material, such as in a channel of the form described above in respect of the first and second rigid horizontal subsidiary support members. The third and fourth rigid horizontal subsidiary support members and the first and second rigid vertical subsidiary support members may define a frame which extends around the second sheet of glazing material. The secondary glazing panel may be fastened to the case by way of adhesive. Alternatively or in addition, at least one mechanical fastener may be used. The mechanical fastener may be a nail or screw that is, for example, driven through each of the first and second rigid vertical support members into the case. The mechanical fastener may be a clip which is configured for releasable fastening of the secondary glazing panel to the case. At least one of the support assembly, such as the first and second rigid vertical support members, and a subsidiary glazing panel frame may be formed from a plastics material such as rigid PVC, aluminium, or wood. The support assembly and / or subsidiary glazing panel frame may be formed by extrusion. A sheet of glazing material of the secondary glazing panel may be formed of plastics material or glass. Where the sheet of glazing material is formed of glass, the glass may be float glass. Furthermore, the glass may be of low light reflectance form. For example, the glass may be Pilkington Optiview™ glass. The sheet of glazing material may be at least one of toughened and laminated. Alternatively or in addition, the sheet of glazing material may be constituted to provide for at least one of increased security, sound proofing, and low reflectance. The sheet of glazing material may comprise a coating to improve thermal performance. According to a second aspect of the present invention there is provided a sash and case window arrangement comprising: a sash and case window lacking vertical staff bead to retain a sash of the sash and case window in place; and a secondary glazing panel fastened to an interior side of the sash and case window, wherein the secondary glazing panel comprises at least one sheet of glazing material and a support assembly comprising first and second rigid vertical support members which each support a respective edge of the at least one sheet of glazing material, the first and second rigid vertical support members are present in place of vertical staff bead, and the first and second rigid vertical support members are disposed relative to one of the sashes of the sash and case window to retain the sash in the case of the sash and case window. Embodiments of the second aspect of the present invention may comprise one or more features of the first aspect of the present invention. Brief Description of Drawings Further features and advantages of the present invention will become apparent from the following specific description, which is given by way of example only and with reference to the accompanying drawings, in which: Figure 1 is a perspective view of an upper part of a prior art sash and case window when in situ in a building; Figure 2 is a view in cross-section through the left-hand side of the sash and case window of Figure 1; Figure 3 shows a secondary glazing panel according to a first embodiment before installation and in sectional view after installation; Figure 4 shows a secondary glazing panel according to a second embodiment before installation and in sectional view after installation; Figure 5 shows a secondary glazing panel according to a third embodiment before installation and in sectional view after installation; Figure 6A shows a secondary glazing panel according to a fourth embodiment before installation; Figure 6B shows one of the subsidiary glazing panels of the fourth embodiment; Figure 6C shows one of the rigid vertical support members of the fourth embodiment; Figure 7A shows a locking mechanism when in an unlocked position; and Figure 7B shows the locking mechanism of Figure 7A when in a locked position. Description of Embodiments An upper part of a prior art sash and case window 10 is shown in Figure 1. A view in cross-section through the left-hand side of the sash and case window of Figure 1 is shown in Figure 2. The sash and case window 10 is in situ, i.e. the sash and case window is part of a building. The sash and case window 10 comprises an upper framed glazing panel (or upper sash) 12, a lower framed glazing panel (or lower sash) 14, and a case 16 which defines a rectangular space in which the upper and lower sashes are held. The sash and case window 10 further comprises three lengths of parting bead 18. Each of two of the three lengths of parting bead 18 extends into the space defined by the case and between the top and the bottom of the case on a respective one of the left- and right-hand sides of the case. The remaining length of parting bead 18 extends into the space defined by the case and between the left- and right-hand sides of the case along the top of the case. The parting bead 18 is on the interior side of the upper sash 12 to thereby present a barrier to movement of the upper sash in the interior direction and to otherwise define a channel with an exterior part of the case in which the upper sash can move upwards and downwards. Furthermore, the parting bead 18 is on the exterior side of the lower sash 14 to present a barrier to movement of the lower sash in the exterior direction. The parting bead 18 therefore protrudes between the upper and lower sashes 12, 14. The sash and case window 10 further comprises three lengths of staff bead 20. Each of two of the three lengths of staff bead 20 is attached to a respective one of the left and right hand sides of the case and such that the length of staff bead protrudes into the space defined by the case and between the top and the bottom of the case. The remaining length of staff bead 20 is attached to the top of the case and such that the length of staff bead protrudes into the space defined by the case and between the left and right hand sides of the case along the top of the case. The lengths of staff bead 20 are fixed by way of screws 22 to the case around the interior side of the sash and case window 10 such that they extend over the periphery of the sashes whereby the staff bead retains the lower sash 14 in place in the case. The lower sash is therefore located between the parting bead 18 and the staff bead 20 with the parting and staff beads defining a channel in which the lower sash can move upwards and downwards. The sash and case window 10 also comprises a pair of weights 24 contained within a weight box 26 on each of left- and right-hand sides of the case. Each pair of weights 24 is suspended from a length of rope 28 which is attached near a respective upper corner of the lower sash 14. The weights 24 counterbalance the weight of the lower sash 14 and thereby provide for ease of upward and downward movement and hence opening and closing of the lower sash. Each of the upper and lower sashes 12, 14 comprises a sash frame 30 which supports and extends around plural sheets of glass 32. Although not shown in Figure 1, the sash and case window 10 also comprises a pair of shutters 34 which are mounted on the interior side of the sash and case window for rotation about a vertical shutter axis 36 whereby each shutter is movable between a stored position and a deployed position in which the shutter overlies a respective one of a left hand side and a right hand side of the sash and case window. A secondary glazing panel 40 according to a first embodiment is shown in Figure 3 before installation and also in cross-section after installation in a sash and case window 10. Parts of the sash and case window 10 of Figure 3 in common with the sash and case window 10 of Figures 1 and 2 are designated with like reference numerals. The reader’s attention is directed to the description provided above with reference to Figures 1 and 2 for description of such common parts. The secondary glazing panel 40 of the first embodiment is of rectangular form and comprises a glazing panel frame 42 and a single sheet of glass 44. The glazing panel frame 42 extends around and supports the single sheet of glass 44. The glazing panel frame 42 defines a channel of rectangular cross-section in each of its opposing left- and right-hand faces and its opposing upper and lower faces. Each of four edges of the sheet of glass 44 is received in a respective section of channel defined by the glazing panel frame 42 whereby the sheet of glass is supported by the glazing panel frame. Each edge of the sheet of glass 44 is an interference fit in the respective section of channel. In a form, adhesive is present in the channel to fix the sheet of glass 44 to the glazing panel frame 42. In a method of installation of the secondary glazing panel 40 according to the invention, the staff bead 20 shown in Figures 1 and 2 is removed from the sash and case window 10. The secondary glazing panel 40 is then moved into position on the interior side of the sash and case window and such that it fits within the space defined by the case. A dimension of the glazing panel frame 42 in a first direction, which is orthogonal to a plane of the sheet of glass 44, is substantially the same as a dimension of the now removed staff bead 20 in the same direction. The glazing panel frame 42 therefore now occupies the same space in the first direction as formerly occupied by the staff bead 20 whereby the glazing panel frame extends no further on the interior side than the staff bead before its removal. The glazing panel frame 42 is then attached firmly to the case by way of screws 46 which are each driven through the glazing panel frame into the case. The secondary glazing panel 40 further comprises a seal 48 mounted on and extending around the glazing panel frame. The seal 48 is Q-Lon foam weatherseal from Schlegel Ltd, Henlow Industrial Estate, Henlow Camp, Bedfordshire, SG16 6DS, United Kingdom. The seal extends along and from oppositely and outwardly directed faces of the vertically extending sections on the left- and right-hand sides of the glazing panel frame 42. The seal 48 also extends along and from the outwardly directed face of each of the upper and lower horizontal sections of the glazing panel frame 42 that extend between the two vertically extending sections. When the secondary glazing panel 40 is installed, the seal 48 is compressed in abutment against the case to thereby provide a seal between the secondary glazing panel and the sash and case window 10. As may be appreciated from comparison of Figures 2 and 3, the shutter 34 of Figure 3 can be rotated about the vertical shutter axis 36 from the stored position to the deployed position and without the glazing panel frame 42 obstructing movement of the shutter to its fully deployed position. A secondary glazing panel 60 according to a second embodiment is shown in Figure 4 before installation and also in cross-section after installation in a sash and case window 10. Parts of the sash and case window 60 of Figure 4 in common with the sash and case window 10 of Figures 1 and 2 are designated with like reference numerals. The reader’s attention is directed to the description provided above with reference to Figures 1 and 2 for description of such common parts. The secondary glazing panel 60 of the second embodiment is of rectangular form and comprises a glazing panel frame 62, an upper sheet of glass 64, and a lower sheet of glass 66. The upper and lower sheets of glass 64, 66 are of substantially the same dimensions. The glazing panel frame 62 defines a first channel of rectangular cross-section in each of its opposing left and right hand faces and in the face of the lower horizontally section of the glazing panel frame which opposes the upper horizontally extending section of the glazing panel frame. The glazing panel frame 62 also defines a second channel of rectangular cross-section in each of its opposing left and right hand faces and in the face of the upper horizontally extending section of the glazing panel frame which opposes the lower horizontally extending section of the glazing panel frame. The first and second channels are spaced apart from each other in the first direction and with the first channel closer to the interior side of the sash and case window 10 than the second channel. Each of three edges of the lower sheet of glass 66 is received in a respective section of the first channel whereby the lower sheet of glass 66 is supported by the glazing panel frame 62. Each edge of the lower sheet of glass 66 is a tight fit in the respective section of the first channel, the fit being sufficiently tight that the lower sheet of glass does not move downwards in the first channel under effect of gravity whilst allowing a user to apply less than undue force to move the lower sheet of glass upwards and downwards in the first channel. Each of three edges of the upper sheet of glass 64 is received in a respective section of the second channel whereby the upper sheet of glass is supported by the glazing panel frame 62. Each edge of the upper sheet of glass 64 is a tight fit in the respective section of the second channel, the fit being sufficiently tight that the upper sheet of glass does not move downwards in the second channel under effect of gravity whilst allowing a user to apply less than undue force to move the upper sheet of glass upwards and downwards in the second channel. One, other or both of the upper and lower sheets of glass 64, 66 can be moved by the user upwards and downwards in the respective first and second channels. Otherwise, the secondary glazing panel 60 of the second embodiment is of the same form as the secondary glazing panel 40 of the first embodiment. For example, the secondary glazing panel 60 comprises a seal 48 formed of rubber mounted on and extending around the glazing panel frame 62 as described above in respect of the first embodiment. Installation of the secondary glazing panel 60 of the second embodiment is the same as described above with respect to the first embodiment. Amongst other steps, installation comprises removal of the staff bead 20 of the sash and case window 10 followed by fitting of the secondary glazing panel 60 on the interior side of the sash and case window in the space defined by the case and such that the glazing panel frame 62 extends substantially no further on the interior side than the staff bead before its removal. The secondary glazing panel 60 thus presents no obstacle to proper closure of the shutters 34. A secondary glazing panel 80 according to a third embodiment is shown in Figure 5 before installation and also in cross-section after installation in a sash and case window 10. Parts of the sash and case window 80 of Figure 5 in common with the sash and case window 10 of Figures 1 and 2 are designated with like reference numerals. The reader’s attention is directed to the description provided above with reference to Figures 1 and 2 for description of such common parts. The secondary glazing panel 80 of the third embodiment is of rectangular form and comprises a glazing panel frame 82, an upper sheet of glass 84, and a lower sheet of glass 86. The upper and lower sheets of glass 84, 86 are of substantially the same dimensions whereby the transition between the upper and lower sheets of glass overlies the transition between the sashes of the sash and case window. The glazing panel frame 82 comprises a main glazing panel frame 88, a first subsidiary glazing panel frame 90, and a second subsidiary glazing panel frame 92. The first subsidiary glazing panel frame 90 extends around and supports the upper sheet of glass 84. The first subsidiary glazing panel frame 90 defines a channel of substantially rectangular cross-section in which edges of the upper sheet of glass 84 are a tight fit with adhesive being used if required to hold the upper sheet of glass 84 securely in the channel. The second subsidiary glazing panel frame 92 extends around and supports the lower sheet of glass 86. The second subsidiary glazing panel frame 92 defines a channel of substantially rectangular cross-section in which edges of the lower sheet of glass 86 are a tight fit with adhesive being used if required to hold the lower sheet of glass 86 securely in the channel. The first subsidiary glazing panel frame 90 is rotatably mounted on the main glazing panel frame 88 such that the first subsidiary glazing panel frame 90 occupies the upper half of the space defined by the main glazing panel frame 88. The second subsidiary glazing panel frame 92 is rotatably mounted on the main glazing panel frame 88 at a location spaced apart from the location of rotatable mounting of the first subsidiary glazing panel frame 90 such that the second subsidiary glazing panel frame 92 occupies the lower half of the space defined by the main glazing panel frame 88. Each of the first and second subsidiary glazing panel frames 90, 92 is mounted on the main glazing panel frame 88 for rotation by way of a pivot hinge located at each of the top left and right corners of the respective subsidiary glazing panel frame. In another form, each of the first and second subsidiary glazing panel frames 90, 92 is mounted on the main glazing panel frame 88 for rotation by way of a hinge stay mechanism at each of the left and right hand sides of the respective subsidiary glazing panel frame instead of by way of the pivot hinges. Each of the first and second subsidiary glazing panel frames 90, 92 therefore rotates about a horizontal axis at its upper edge. As can be seen from the cross-sectional view in Figure 5, the main glazing panel frame 88 is L-shaped with each of the first and second subsidiary glazing panel frames 90, 92 nestling one above the other in the angle of the L-shaped main glazing panel frame when the subsidiary glazing panel frame is in registration with the main glazing panel frame (i.e. when the subsidiary glazing panel frames are closed). A first leg of the L-shaped main glazing panel frame 88 faces the case of the sash and case window 10 and the second leg of the L-shaped main glazing panel frame faces a sash of the sash and case window. Screws 46 are driven through the first leg of the L-shaped main glazing panel frame 88 and into the case to attach the secondary glazing panel 80 to the sash and case window. The secondary glazing panel 80 further comprises a glazing panel frame seal 94 which is mounted on and extends from the second leg of the main glazing panel frame 88 and on the side of the second leg facing away from the sash. The glazing panel frame seal 94 is formed of rubber. When the first or second subsidiary glazing panel frame 90, 92 is in registration with the main glazing panel frame 88, the glazing panel frame seal 94 abuts against the subsidiary glazing panel frame. The pivot hinges of each of the first and second subsidiary glazing panel frames 90, 92 are configured such that the subsidiary glazing panel frame can be detached from the main glazing panel frame 88 when the subsidiary glazing panel frame has been rotated upwards relative to the main glazing panel frame to sufficient extent, such as beyond 90 degrees. Otherwise, the secondary glazing panel 80 of the third embodiment is of the same form as the secondary glazing panel 40 of the first embodiment. For example, the secondary glazing panel 80 comprises a seal 48 formed of rubber mounted on and extending around the outside of the main glazing panel frame 88 as described above in respect of the first embodiment. Installation of the secondary glazing panel 80 of the third embodiment is the same as described above with respect to the first embodiment. Amongst other steps, installation comprises removal of the staff bead 20 of the sash and case window 10 followed by fitting of the secondary glazing panel 80 on the interior side of the sash and case window in the space defined by the case and such that the main glazing panel frame 88 and the first and second subsidiary glazing panel frames 90, 92 when they are in registration with the main glazing panel frame extend substantially no further on the interior side than the staff bead 20 before its removal. The secondary glazing panel 80 of the third embodiment thus presents no obstacle to proper closure of the shutters 34. The frames of each of the first to third embodiments of secondary glazing panel 40, 60, 80 are formed of extruded rigid PVC, extruded aluminium, or wood. The glass panels of each of the first to third embodiments of secondary glazing panel 40, 60, 80 are formed of Pilkington Optiview™ glass. A secondary glazing panel 100 according to a fourth embodiment is shown in Figure 6A before installation in a sash and case window. Figure 6B shows one of the subsidiary glazing panels of the fourth embodiment and Figure 6C shows one of the rigid vertical support members of the fourth embodiment. Parts of the fourth embodiment 100 in common with previous embodiments are designated with like reference numerals. The reader’s attention is directed to the description provided above for description of such common parts. The fourth embodiment of secondary glazing panel 100 comprises a support assembly which comprises a first rigid vertical support member 102 and a second rigid vertical support member 104. The first rigid vertical support member 102, which is shown in Figure 6A, is installed in place of the vertical staff bead on the left-hand side of the sash and case window and the second rigid vertical support member 104, which is shown in Figure 6B, is installed in place of the vertical staff bead on the right-hand side of the sash and case window. The method of installation according to the present embodiment therefore involves removal of the vertical staff bead only whereby the horizontal staff bead is left in place. Each of the first and second rigid vertical support members 102, 104 is L-shaped like the main glazing panel frame 88 of the third embodiment. Furthermore, and in common with the main glazing panel frame 88 of the third embodiment, each of the first and second rigid vertical support members 102, 104 comprises a glazing panel frame seal 94 which is formed of rubber and is mounted on and extends from the second leg of the vertical support member facing away from the sash. In addition, each of the first and second rigid vertical support members 102, 104 comprises a seal 48 as described above in respect of the first embodiment and which is formed of rubber and is mounted on the first leg of the vertical support member such that the seal 48 faces the case. The fourth embodiment of secondary glazing panel 100 further comprises a first subsidiary glazing panel 106 and a second subsidiary glazing panel 108. Each of the first and second subsidiary glazing panels 106, 108 has the same form. Each of the first and second subsidiary glazing panels 106, 108 comprises first and second rigid vertical subsidiary support members 110, 112 and a sheet of glazing material 114. The first rigid vertical subsidiary support member 110 is attached to the lefthand edge of the sheet of glazing material 114 and the second rigid vertical subsidiary support member 112 is attached to the right-hand edge of the sheet of glazing material whereby the sheet of glazing material is supported by the first and second rigid vertical subsidiary support members 110, 112. As may be seen from Figure 6A, each of the first and second rigid vertical subsidiary support members 110, 112 defines first and second oblique grooves 116, 118 which are spaced apart along the subsidiary support member. Figure 6B shows the first oblique groove 116 in more detail. As may be seen from Figure 6B, the groove extends obliquely upwards to a closed end from an opening in a side of the subsidiary support member which faces the respective vertical support member 102, 104. As may be seen from Figure 6A, each of the first and second rigid vertical support members 102, 104 has four hinge pins 120 which extend from and are spaced apart along the first leg such that the hinge pins are at locations corresponding to the first and second oblique grooves 116, 118 in the first and second rigid vertical subsidiary support members 110, 112. The support assembly and the first and second rigid vertical subsidiary support members 110, 112 of the fourth embodiment of secondary glazing panel 100 are formed of extruded rigid PVC, extruded aluminium, or wood. The sheets of glazing material 114 of the fourth embodiment of secondary glazing panel 100 are formed of Pilkington Optiview™ glass. As mentioned above, installation according to the fourth embodiment involves removal of the vertical staff bead only. The first and second rigid vertical support members 102, 104 are then attached to the case of the sash and case window in place of the removed vertical staff bead. Each of the first and second subsidiary glazing panels 106, 108 is fitted in turn to the now attached first and second rigid vertical support members 102, 104 by positioning the appropriate hinge pins 120 in registration with the openings to the grooves 116 and then lowering the subsidiary glazing panel whereby the hinge pins 120 travel along their respective grooves until they reach the closed ends of the grooves. When the hinge pins 120 have reached the closed ends of the grooves 116, the subsidiary glazing panel 106, 108 is in registration with the first and second rigid vertical support members 102, 104 with the glazing panel frame seal 94 abutting against the subsidiary glazing panel. Although not shown in Figure 6A, the fourth embodiment comprises three glazing sheet seals. Each glazing sheet seal is strip-form and is formed of rubber or plastics material. A first glazing sheet seal extends along the upper edge of the sheet of glazing material 114 of the first subsidiary glazing panel 106. A second glazing sheet seal extends along the lower edge of the sheet of glazing material 114 of the second subsidiary glazing panel 108. The first and second glazing sheet seals form a seal with the still present horizontal staff bead respectively at the top and bottom of the sash and case window. The third glazing sheet seal is mounted on one or other of the lower edge of the sheet of glazing material 114 of the first subsidiary glazing panel 106 and the upper edge of the sheet of glazing material 114 of the second subsidiary glazing panel 108 and such that the third glazing sheet seal bridges the gap between the two sheets of glazing material 114. According to a fifth embodiment of secondary glazing panel, the third embodiment 80 of Figure 5 is modified such that the glazing panel frame 82 is replaced with the first and second rigid vertical support members 102, 104 of the fourth embodiment. This means the fifth embodiment of secondary glazing panel is brought into use in the same way as the fourth embodiment by removal of the vertical staff bead only whereby the horizontal staff bead is left in place. Further to this, according to the fifth embodiment the third embodiment 80 of Figure 5 is also modified such that each of the first and second subsidiary glazing panel frames 90, 92 is replaced with the first and second rigid vertical subsidiary support members 110, 112 of the fourth embodiment. Otherwise, the fifth embodiment of secondary glazing panel comprises further features of the fourth embodiment such as the three glazing sheet seals. As described above with respect of the second embodiment, each edge of the upper sheet of glass 64 is a tight fit in the respective section of the second channel, the fit being sufficiently tight that the upper sheet of glass does not move downwards in the second channel under effect of gravity whilst allowing a user to apply less than undue force to move the upper sheet of glass upwards and downwards in the second channel. In another embodiment, the fit is insufficiently tight whereby the upper sheet of glass is inclined to move downwards in the second channel under effect of gravity. In this embodiment, the secondary glazing panel comprises the locking mechanism 130 shown in Figures 7A and 7B. The locking mechanism 130 of Figures 7A and 7B comprises a lock support member 132 and a rotatable member 134 which are rotatably coupled to each other. The lock support member 132 is mounted on at least one of the left- and right-hand side members (which constitute first and second rigid vertical support members) of the glazing panel frame 62 between the first and second channels. The rotatable member 134 rotates relative to the lock support member 132 to provide for movement between unlocked and locked positions. In the locked position shown in Figure 7B the rotatable member 134 presses against the upper sheet of glazing material 64 such that the upper sheet of glazing material is urged against one side of 5 the channel in which the sheet of glazing material is received to thereby present resistance to movement of the upper sheet of glazing material down the channel. In the unlocked position shown in Figure 7A the rotatable member 134 is spaced apart from the upper sheet of glazing material 64 to thereby allow for ease of movement of the upper sheet of glazing material along the channel. io 29 11 24

Claims

1. A method of installing a secondary glazing panel in a sash and case window, the secondary glazing panel comprising at least one sheet of glazing material and a support assembly, the support assembly comprising first and second rigid vertical support members which each support a respective edge of the at least one sheet of glazing material, the method comprising:removing vertical staff bead of the sash and case window from an interior side of the sash and case window;positioning the secondary glazing panel on the interior side of the sash and case window such that the first and second rigid vertical support members of the secondary glazing panel are located in place of the removed vertical staff bead; andfastening the secondary glazing panel to the case of the sash and case widow whereby the support assembly of the secondary glazing panel retains one of the sashes of the sash and case window in the case, in which:the secondary glazing panel comprises first and second sheets of glazing material which are supported by the first and second rigid vertical support members such that they close different parts of the space defined between the first and second rigid vertical support members;at least one of the first and second sheets of glazing material is supported by the support assembly for movement in the support assembly and relative to the other sheet of glazing material to increase or reduce an extent of overlap of the first and second sheets of glazing material;each of the first and second rigid vertical support members defines first and second channels which are spaced apart from each other in a first direction from the exterior of the sash and case window to the interior of the sash and case window, each of the first and second sheets of glazing material accommodated in a respective one of the first and second channels; andeach of the first and second sheets of glazing material is fitted in a respective one of the first and second channels and such that the fit is insufficiently tight to hold the sheet of glazing material in the channel against the effect of gravity, the sash and case window arrangement comprising a locking mechanism to hold an upper one of the first and second sheets of glazing material in the channel against the effect ofgravity, the locking mechanism movable between a locked position and an unlocked position, in the locked position the locking mechanism or part thereof pressing against the sheet of glazing material such that the sheet of glazing material is urged against one side of its channel, and in the unlocked position the locking mechanism or the part thereof spaced apart from the sheet of glazing material.

2. The method of claim 1, in which the first and second rigid vertical support members of the secondary glazing panel extend in the first direction orthogonal to a plane of the at least one sheet of glazing material of the secondary glazing panel, the first and second rigid vertical support members extending in the first direction such that their extremities do not abut against a shutter comprised in the sash and case window and when the shutter is being closed over the sash and case window.

3. The method of claim 2, in which a dimension of each of the first and second rigid vertical support members of the secondary glazing panel in the first direction is no more than a dimension in the first direction of the removed vertical staff bead.

4. The method of any one of the preceding claims, in which the secondary glazing panel comprises a seal which extends from each of the first and second rigid vertical support members, each seal mounted on a respective one of the first and second rigid vertical support members such that it abuts against a part of the sash and case window remaining after removal of the vertical staff bead.

5. The method of claim 4, in which each seal extends from a surface of each of the first and second rigid vertical support members, the seal extending in a direction parallel to a plane of the at least one sheet of glazing material and in a direction away from the at least one sheet of glazing material whereby the seal abuts against the case when the secondary glazing panel is positioned on the interior side of the sash and case window.

6. The method of any one of the preceding claims, in which the first channel is closer to the sashes of the sash and case window than the second channel, an upper one of the first and second sheets of glazing material accommodated in thefirst channel, and a lower one of the first and second sheets of glazing material accommodated in the second channel.

7. The method of any one of the preceding claims, in which at least one of the first and second channels is of greater extent along its length in a direction between a top and a bottom of the sash and case window than the respective sheet of glazing material whereby the respective sheet of glazing material is movable upwards and downwards in the support assembly.

8. The method of claim 7, in which at least one of the first and second channels extends from adjacent a top of the respective one of the first and second rigid vertical support members to adjacent a bottom of the vertical support member whereby at least one of the first and second sheets of glazing material is movable from the top of the first and second rigid vertical support members to the bottom of the first and second rigid vertical support members and vice-versa.

9. The method of any one of the preceding claims, in which the locking mechanism comprises a lock support member and a rotatable member which are rotatably coupled to each other, the rotatable member rotating relative to the lock support member to provide for rotation between the unlocked and locked positions, the lock support member mounted on the vertical support member between the first and second channels.

10. The method of any one of the preceding claims, in which at least one of thefirst and second sheets of glazing material is supported by the support assembly for rotation relative to the support assembly, each at least one of the first and second sheets of glazing material is supported for rotation of the respective sheet of glazing material about an axis of rotation that extends across a width of the secondary glazing panel.

11. The method of any one of the preceding claims, in which the first sheet of glazing material is separable from the support assembly by way of a user operable retention mechanism that allows for separation of the first sheet of glazing materialupon user operation and that otherwise attaches the first sheet of glazing material to the support assembly.29 11 24

Images