GB2573142A - Sash window assembly - Google Patents

Abstract

A sash window assembly comprises a window frame which includes a sash panel 16 which is slidably mounted to the window frame, and a window balance system 44 which includes a resilient means 48, and elongate flexible sash connector 46 connected at one end to the sash panel, and connected at the other end to the resilient means, and a pulley wheel 52 mounted on the window frame and around which the sash connector passes. The sash connector and pulley wheel are at least partially exposed and the resilient means is concealed within the window frame. The sash window assembly thereby provides the aesthetic benefits of a traditional sash weight and pulley operated assembly, with the improved functionality of a more modern resiliently balanced assembly. Also included is a coupling device (50, Fig 6) for a sash window balance assembly comprising a body portion (64, Fig 6) and a support plate (66, Fig 9).

Description

SASH WIN DOW ASSEMBLY

The present invention relates to a sash window assembly, and in particular, but not limited to, a sash window assembly comprising a window balance system.

Windows in residential, commercial and industrial buildings may include one or more sash windows that comprise one or more moveable panels, or sashes, which are formed by a sash frame holding individual panes of glass. The panels are held within channels in a window frame and are opened by sliding them vertically or horizontally, with respect to each other.

Movement of the sashes is enabled by two or more window balance assemblies or systems, usually with one window balance assembly located either side of the sashes in a channel located in the side portion of the window frame. The window balance assemblies usually comprise a sash weight, typically made of lead or cast-iron, connected to the window via a sash cord or chain that runs over a pulley positioned at the top of the frame. In traditional sash windows in particular, the cord is usually made of braided cotton. The sash weight acts as a counterbalance to the weight of the sash, and as such, assists a user in moving the window sash to position it as required in the frame, i.e. in an open or closed position.

The weight is concealed behind a panel in each side of the window frame (often referred to as a box frame). The sash weight is selected based on the weight of the sash, such that in the event that the weight of the sash is altered, such as when replacement glass is fitted, the sash weight may require adjusting or replacing to maintain correct operation of the sash.

As an alternative to the traditional pulley, cord and sash weight system, a spring balance system can be used. The spring balance is a pre-tensioned spring loaded mechanism that counter-balances the weight of an individual sash in the sash window frame. The force of the spring correlates to a weight range of window sashes that can be accommodated by the spring balance. It eliminates the need for sash weights, sash cords and pulleys.

One of the benefits of a spring balance system over the traditional sash weights system is that the window frame (reveal) is slimmer because there is no need for the bulky box-section reveal to hide bulky weights from view. The spring balance is either exposed in the window jamb, or is covered by a panel. Slimmer sightiines also mean that the glass area of the window becomes larger, thus allowing more natural light in through the window.

Use of a spring balance also eliminates the need for replacement or adjustment of sash weights in the event of refurbishment of the sash window or glass. Replacement or adjustment of the sash weight system is often necessary following re-glazing, because older box sash windows will have been weighted for 3mm glass, whereas modern glass is usually 4mm thick. The consequential increase in window weight requires the sash balance weights to be adjusted to ensure the window still operates correctly. However, spring balances are configured to counterbalance a range of weights, and, even if they require adjusting to compensate fora significant change in weight, such adjustment is effected simply by modifying the tension on the spring. Spring balances also allow for a smoother sash ride, making the window more easily operable, as compared with traditional sash weight systems.

However, the more contemporary appearance of spring balance systems is generally not favoured when a more traditional look is required, such as in older buildings and/ or those subject to heritage considerations.

The present invention is intended to address the issues with the prior art systems.

In accordance with a first aspect of the invention, a sash window assembly comprising: a window frame; a sash panel slidably mounted to the window frame; and a window balance system comprising: a resilient means, an elongate flexible sash connector connected at one end to the sash panel and connected at the other end to the resilient means, and a pulley wheel mounted on the window frame around which the sash connector passes; wherein the sash connector and pulley wheel are at least partially exposed and the resilient means is concealed within the window frame.

The invention thereby provides the aesthetic benefits of a traditional sash weight and pulley operated sash window assembly, with the improved functionality of a more modem resiliently balanced sash window assembly. This configuration is particularly advantageous when used in properties requiring a more traditional appearance, and/or those with heritage considerations. This configuration also eliminates the bulky box window frame used to conceal traditional sash weights, and instead, provides slimmer sightlines, due to the more compact nature of the resilient means, thus allowing for larger glazing panels and consequently more light to pass through the window.

The window balance system may be installed within a channel located in at least one of the window frame members, such as one or both side jambs, the header jamb, or sill.

Some or all of each of the sash connector and pulley may be become obscured when the first sash panel is opened.

The sash connector may comprise one or more of a cord, rope, cable, belt, wire, or chain.

The resilient means may comprise a spring. For example, the resilient means may be a spring balance, a spiral balance, or any spring-loaded device capable of counter-balancing the weight of a sash window.

The resilient means may comprise fixing means for attaching the resilient means to the sash window frame. For example, the resilient means may comprise one or more hooks, fasteners, apertures, loops, and/or projections, adapted to fix the resilient means to a surface or to one or more corresponding securing portions or features located on a part of the window frame.

The sash window frame may comprise complementarily shaped securing portions capable of securely engaging with said fixing means. The securing portions may comprise one or more hooks, fasteners, apertures, loops, anchors and/or projections.

The pulley wheel may comprise metal.

The pulley wheel may be rotatably mounted on a portion of the window frame, for example, on a side jamb of the window frame, for example, towards the uppermost section of the side jamb, as viewed when the window frame is installed.

The pulley wheel may comprise a groove around its outer surface, the groove being adapted to receive the sash connector. For example, the groove may be arranged about the circumference of the pulley wheel.

The pulley wheel may be configured to be rotatably supported on an axle or shaft, the axle or shaft may be secured to a portion of the sash window frame.

The axle or shaft may be secured to an upper region of one or more side frame members of the window frame, optionally within a jamb located in the one or more side frame members, as viewed when the window is installed.

The axle or shaft may be secured to an opposite end of the side frame member or jamb channel, relative to the positioning of the resilient means.

The sash connector may be adapted to run over the pulley wheel and within the groove.

The resilient means may be positioned towards one end of a jamb channel. For example, the resilient means may be positioned and secured towards the lower end of a side jamb channel, as viewed when the window is installed.

The window balance system may further comprise one or more infill panels configured to be positioned over the resilient means and removably attached to a part of the window frame, to conceal the resilient means within the window frame. This concealment by the one or more infill panels assists in maintaining a traditional look to the sash window assembly.

The infill panei(s) may be adapted to be removably attached to one or more window jambs, such as a side jamb.

At least a part of each of the sash connector and pulley wheel may be positioned adjacent the outermost surface of the infiil panel, to enable them to remain visible when the first sash panel is in a closed, or partially dosed position. This configuration assists in maintaining a traditional look to the sash window assembly.

For example, a section of the infill panel may be arranged to fit around the pulley wheel to keep it visible, and/or at least a section of the cord may run over on top of the outermost surface of the infiil panel.

The sash connector may be attached to the resilient means directly. For example, an end of the sash connector may be fixed, tied or otherwise secured to an anchor point or connecting point on the resilient means.

The sash connector may be attached to the resilient means via a coupling device.

The coupling device may comprise a body portion and a support plate.

The body portion of the coupling device may comprise one or more channels for receiving one or more edges, end or side walls of the support plate.

The support plate may abut at least a part of the body portion, such as the underside of the body portion.

At least a part of the body portion may comprise an aperture for disposing within an end of the sash connector.

The body portion may comprise one or more apertures for receiving fastening means.

At least one of the apertures for fastening means may be aligned in a different plane relative to the aperture for the sash connector. For example, at least one of the apertures for fastening means may be arranged in a plane generally perpendicular to the plane of the sash connection aperture.

The coupling device may comprise one or more fastening means. The fastening means may comprise a screw thread.

At least one of the fastening means may engage with, or pierce, a part of the sash connector.

The one or more fastening means may secure the support plate to the body portion. The connection of the support plate to the body portion assists in distributing stresses applied to the coupling device across the whole of the support plate and body portion, thus eliminating regions of stress concentration within the coupling device.

The support piate may comprise a plurality of spaced apart grooves, for example, two or three spaced apart grooves.

At least one of the grooves may be adapted to receive at least a part of the end of the sash connector disposed within the aperture.

The sash connector may be received in more than one of the grooves simultaneously, for example, when a sash connector of greater size is required. By way of non-limiting example, a sash connector having a diameter of approximately 6mm may fit entirely within one of the grooves, and a sash connector having a greater diameter may be positioned across more than one of the grooves. In such an example, the sash connector aperture may be elongate to accommodate the larger sash connector.

At least one of the apertures may be arranged to overlie at least one of the grooves when the support piate is abutted against the body portion of the coupling device. For example, one of the apertures for fastening means may overiie at least one of the grooves.

The support plate may be secured to the body portion by way of fasteners, secured through apertures in the body portion and into corresponding apertures in the support plate, thus trapping the sash connector between the grooves of the support plate, and the body portion, respectively. In some embodiments, for example those comprising an elongate sash connector aperture, more than one of the fasteners may also engage with, or pierce, a part of the sash connector.

The body portion of the coupling device may comprise one or more attachment points for connecting the resilient means.

The one or more attachment points may comprise one or more of a channel, an anchor, a projection, a hook, and/or a loop, or any other suitable attachment means.

The coupling device may comprise at least one rotatable or pivoting component.

The coupling device may comprise a pivot shoe.

The sash window assembly may further comprise at ieast one window pivot bar. The pivot bar is preferably adapted to be connected to the pivotable component of the coupling device or pivot shoe. At least one window pivot bar may be attached at one end to one of the sash panels, and at the other end to the coupling device. The pivot bar, when connected to the sash panel and rotatable or pivoting component of the coupling device, or pivot shoe, respectively, allows the sash panel to be tilted away from the plane of the window.

In accordance with a second aspect of the invention, a coupling device for a sash window balance assembly, the coupling device comprising a body portion and a support plate reieasably connected to the body portion, the coupling device adapted to receive one end of an elongate flexible sash connector and having a portion connectable to a resilient means, wherein the body portion further comprises at least two apertures, the first aperture being adapted to receive the said one end of the sash connector and arranged in a first plane, and the second aperture being adapted to receive a fastener and arranged in a second plane, relative to the first aperture.

The body portion may comprise one or more channels for receiving one or more side walls or edges of the support plate.

The coupling device may further comprise one or more fastening means. At least one of the fastening means may be arranged to pierce a section of a sash connector, for example when the sash connector is positioned within the first aperture.

The support plate may comprise one or more grooves across one or more of its edges or side walls.

At least one of the grooves is adapted to receive a portion of a sash connector, and at least one of the grooves is positioned below one of the apertures.

The support plate may be secured to the body portion by way of fasteners, secured through apertures in the body portion and into corresponding apertures in the support plate, thus trapping the sash connector between the grooves of the support plate, and the body portion, respectively. In some embodiments, for example those comprising an elongate sash connector aperture, more than one of the fasteners may also engage with, or pierce, a part of the sash connector.The coupling device may further comprise a connector for receiving an end of a resilient means, such as a spring, a spiral balance, or any such similar resilient means capable of counterbalancing the weight of a sash panel in a sash window arrangement.

The body portion of the coupling device may comprise a pivoting component. The pivoting component may be adapted to receive a window attachment means, such as but not limited to a window pivot bar. in one or more embodiments, the body portion may comprise a pivot shoe.

The body portion may comprise plastic. The support plate may comprise metai.

By way of example only, specific embodiments of the present invention will now be described, with reference to the accompanying drawings, in which:

Fig. 1 is a schematic and front view of a first embodiment of sash window assembly, in accordance with the present invention, as seen from an external aspect when the window is installed;

Fig. 2 is a schematic and perspective view of the sash window assembly shown in Fig. 1, as seen from an internal aspect when the window is installed (sash furniture has been omitted for clarity purposes), wherein a part of the side member of the window frame has been removed to expose its interior and illustrate a first embodiment of a window balance system, in accordance with the present invention;

Fig. 3 is a perspective view of the sash window assembly shown in Fig. 2, illustrating concealment of the spring balance section of the window balance system, in the jamb channel when the sash window is in a partially open position;

Fig. 4 is a schematic view of the window balance system shown in Figs 2 and 3.

Fig. 5 is a cross-sectional view of a portion of the sash window assembly shown in Fig. 2, illustrating the upper and lower sash panels and a pair of sash connector, each attached to a side member of each of the upper and lower panels, respectively;

Fig. 6 is a perspective view of an embodiment of sash connector coupling device, in accordance with the present invention;

Fig.7 is a perspective and partial cross-sectional view of the sash connector coupling device shown in Fig. 8, illustrating the engagement of the central fixing with the sash connector; and

Fig. 8 is a view from above and one end of the sash connector coupling device shown in Fig. 6, illustrating the support plate abutted to the body portion of the coupling device; and

Fig. 9 is a view from the side and underneath of the support plate of the coupling device.

One embodiment of sash window assembly 10, as shown in Fig. 1, generally comprises a window frame 12, an upper sash 14 and a lower sash 16. The window frame 12 typically comprises a generally horizontally orientated bottom sill 18, a horizontally orientated header frame member (“header jamb”) 20, a first side frame member (“side jamb”) 22, and a second side frame member (side jamb) 24, positioned between the each end of the siii 18 and header jamb 20, respectively, and perpendicularly to each, to create a box-like structure.

Each of the upper and lower sashes 14,16 comprises a bottom sash rail 26a, 26b and a top sash rail 28a, 28b, which are horizontally orientated and joined by two vertically orientated side sash rails 30a, 30b, 32a, 32b; one side rail at each end of the top and bottom sash rails 26a, 26b, 28a, 28b, so as to form a generally rectangular shaped sash frame.

The upper and lower sashes 14, 16 each hold a double glazed panel 34a, 34b, i.e. two glazing panels, disposed parallel to one another within a sealed unit, in the present embodiment, each of the sashes 14, 16, further comprise a centrally positioned vertical sash bar 36a, 36b on the glazed panel 34a, 34b, which gives the appearance of two glazing panels disposed side by side in each sash 14, 16.

The upper and lower sashes 14, 16 are offset from each other in a generally perpendicular direction, relative to the plane of the window 10. The upper sash 14 is positioned outermost, i.e. towards the exterior side of the sash window 10, and the lower sash 16 is positioned innermost, i.e. towards the interior side of the sash window 10.

Figs. 2 and 3 illustrate a perspective view of an embodiment of sash window 10 in accordance with the present invention.

As seen from the Figures, each of the upper and lower sashes 14, 16 is arranged to slide in respective channels 38, 40 formed in the side jambs 22, 24 of the window frame 12. The channels 38, 40 are separated in each side jamb 22, 24 by a parting bead 42, which is a long, narrow vertical seal. The channels 38, 40 allow the upper and lower sash windows 14, 16 to at least partially slide past each other as the windows 14, 16 are moved between their respective open and closed positions, and hold the sash windows 14, 16 in their respective positions in the window frame 12.

Movement of the sash windows 14, 16 is controlled by a window balance system 44 which is installed in the side jambs 22, 24 of the window frame 12, as will be described, in the present embodiment, one window balance system 44 is installed in each of the side jambs 22, 24. The pair of window balance systems controls movement of a single sash 14/16, which, in the present embodiment, is the lower sash 16.

Embodiments of sash window comprising two pairs of window balance systems 44 operate in the same manner as that described for movement of the Sower sash 16, with the exception that the additional pair of window balance systems 44 allows independent movement of both the upper and lower sashes, respectively.

Fig. 3 iilustrates an embodiment of a window balance system 44, in accordance with the present invention and for use in a sash window assembly 10. The window balance system 44 comprises a length of sash connector in the form of a sash cord 46, attached to a resilient means in the form of a known spring balance 48, by means of a coupling device 50, (illustrated schematically in Figs 2-4). The balance system 44 also comprises a pulley wheel 52, adapted to be secured to the window frame 12 via a mounting plate, and to allow the sash cord 46 to pass over the outer surface of the pulley wheel 52, as will be explained.

The sash cord 46 comprises a length of 6mm diameter waxed braided cotton cord, which gives the appearance of a traditional sash balance cord. The cord 46 has a polyester core which is not visible externally. This ensures that the cord 46 retains the traditional look and feel, whilst giving the cord 46 additional strength.

The spring balance 48 comprises a known spring balance assembly. The spring balance 48 includes a coil spring (not visible), encased in a tubular housing 54, the tubular housing 54 being surrounded by an outer casing 56 which offers additional strength and protection to the spring balance 48. Typically, the spring balance 48 is capable of supporting one-half the weight of each sash 14/16, when the spring is extended.

In the present embodiment, the spring balance 48 has a helical rod 58 extending downwardly from the tubular housing 54. The helical rod 58 comprises a sash attachment point (not visible) for securely engaging with an attachment block 60 mounted on the uppermost surface of the bottom sill of the jamb channels 38, 40.

At the other end, the spring balance 48 has a balance rod 62 extending upwardly from the housing 54. The balance rod 62 is arranged to securely engage with a section of the coupling device 50, as will be explained. This enables a secure coupling between the window frame 12 and the spring balance 48, and the spring balance 48 to the sash cord 46, respectively.

The sash cord 46 and spring balance 48 are connected together by the coupling device 50. The coupling device 50 is arranged to slide in the jamb channels 38, 40, to allow the lower sash 16 to be raised and lowered in the traditional manner, i.e. by lifting the sash 16 using a pair of sash lifts (not shown) attached to the bottom sash rail 26.

The coupling device 50 comprises a generally rectangular cuboid shaped plastic body portion 64, and a metal support plate 66, as will be explained. The coupling device 50 is shaped and sized to fit within each of the side jamb channels 38,40, to allow it to slide vertically up and down each channel 38/ 40. The body portion 64 comprises a top face 68, a bottom face (not visible), a first end face 70, a second end face 72, and two side faces 74, 76.

The end third of the body portion 64 adjacent the first end face 70 is substantially solid in construction, with the exception of having three spaced apart apertures 78a, 78b, 78c, positioned substantially halfway along said end third, and a channel 80 for receiving a portion of the support plate 66, The remainder of the body portion 46 is generally hollow, as will be explained.

The sides of the end third of the body portion 64 extend towards the second end face 72 to form side arms 82, 84 depending from the end third of the body portion 64 and defining the hollow interior of the body portion. The side arms 82, 84 are connected together by a balance rod connector 86 which bridges the two side arms 82, 84, as will be explained. The centre of the body portion 64 is therefore hollow and bounded by the end third of the body portion 64, side arms 82, 84 and balance rod connector 86.

As seen from Fig. 7, the end third of the body portion 64 comprises a channel 80 that runs parallel to the end face 70 of the body portion, for receiving a first end wall portion 88 of the metal support piate 66, as will be explained. A corresponding channel (not visible) is positioned at the opposite end of the end third of the body portion 64, adjacent the balance rod connector 86, and also runs parallel to the end face 70, for receiving a second end wall portion 90 of the metal support plate 66.

As mentioned above, the end third of the body portion 64 comprises three spaced apart apertures 78a, 78b, 78c which extend between the fop face 68 and the bottom face of the body portion 64. The apertures 78a, 78b, 78c are arranged in a straight line between the side faces 74, 76 of the body portion 64 and approximately half way down the end third of the body portion 64. Each of the apertures 78a, 78b, 78c is adapted to receive a threaded fastener 92a, 92b, 92c, as will be explained. In use, when the support plate 66 and body portion 64 are abutted, the first and second end wall portions 88, 90 mate with the channels 80 either side of, and running parallel to the line of spaced apart apertures 78a, 78b, 78c.

As best seen in Fig. 6, the end face 70 of the end third of the body portion 64 comprises a cord receiving aperture 94, into which one end of the sash cord 46 is threaded. The end of the sash cord 46 is threaded through the whole end third of the body portion 64 and into the hollow central space of the body 64,

The cord receiving aperture 94 is also more generally referred to herein as the first aperture. The centra! aperture 78b of the three apertures 78a, 78b, 78c is also more generally referred to herein as the second aperture.

The sash cord 46 is secured in the cord receiving aperture 94 by the threaded fastener 92b inserted into the central aperture 78b. The fastener 92b therefore intersects the path of the sash cord 46 when it has been threaded into the cord receiving aperture 94, thus piercing the sash cord 46. This ensures a secure connection of the sash cord 46 to the coupling device 50.

The other end of the coupling device 50 comprises the balance rod connector 86. The balance rod connector 86 comprises a moulded section of the body portion 64 that bridges the two side arms 82, 84.

The balance rod connector 86 comprises a planar base portion (not visible) having two opposing, generally right-angled triangular side portions 96a, 96b extending upwardly from either side of the base portion to form a channel 98 between the two opposing faces 100a, 100b of each side portion 96a, 96b that extend generally perpendicularly from the base portion. One of the side portions 96a comprises a triangular shaped projection 102 towards the uppermost tip. The base or underside 104 of the projection 102 is arranged to abut the uppermost surface of the balance rod 62 of the spring balance 48, when the balance rod 62 is positioned in the channel 98.

The balance rod 62 is inserted into the channel 98 to connect the spring balance 48 and coupling device 50 together. The distal end of the balance rod 62 extends into the hollow centre portion of the body 64. The upper surface of the balance rod 62 abuts the underside 104 of the projection 102 on the side portion 96a, to prevent the rod 62 from moving upwards and out of the channel 92.

The balance rod 62 further comprises an aperture 106 at its distal end, for receiving a dowel 108. The dowel 108 is positioned centrally within the aperture 106 such that it extends outwardly either side of the aperture 106 and balance rod 62 to form a generally T-shaped configuration. The dowel 108 provides an additional mechanism by which the balance rod 62 is secured to the coupling device 50, by preventing the balance rod 62 from sliding out of the channel, by abutting against the innermost wall of the balance rod connector 86,

As mentioned above, the coupling device 50 comprises a metal support plate 66. The support plate 66 comprises a planar base portion 114 and two opposing end wall portions 88, 90, extending upwardly and generally perpendicularly, from the base portion 114, to form a generally bridge-like shape.

The planar base portion 114 comprises two spaced apart apertures 116, 118 with one aperture positioned towards each edge of the base portion 114, and substantially halfway between the two end wall portions 88, 90.

Each of the end wall portions 88, 90 comprises three spaced apart grooves 120a, 120b, 120c; 122a, and 122b, (122c not visible) in the uppermost edge of the end walls 88, 90.

The grooves 120a-c; 122a-c are positioned centraiiy between the ends of each of the end walls 88, 90.

The end wail portions 88, 90 fit within the channeis 80 on the underside of the body portion 84, to enable the base 114 of the support plate 86 and body portion 64 to abut one another. This contact of the two components allows for stresses applied to the coupling device 50 in use, to be distributed across the whole of the metal support plate 66, thus preventing regions of stress concentration accumulating in the piastic body portion 84 which might otherwise cause the coupling device 50 to fail.

Furthermore, the support plate 66 acts as an additional securing mechanism for the sash cord 46, as will be explained.

The centremost groove 120b of the support plate 66 lies below the cord receiving aperture 94 so that when the sash cord 46 is threaded into the aperture 94, the underlying, generally v-shaped groove 120b slightly compresses the sash cord 46 to provide further resistance against removal of the cord 46 during use. The sash cord 46 is further retained securely in the groove by virtue of the fastener 92b inserted into the aperture 78b, which punctures the sash cord 46 to retain in securely within the body portion 64, as explained above. The coupling device 50 can therefore maintain a secure connection of the sash cord 46 and spring balance 48 as it moves in a vertical plane in the jamb channel 38/ 40 in response to movement of the sash panel 16. The support plate 66 is further secured to the body portion 64 by virtue of fasteners 92a, 92c positioned in the two outermost apertures 78a, 78c in the body portion 64 that engage with the apertures 116, 118 in the planar base portion 114 of the support plate 86.

As explained above, in use, one end of the sash cord 46 is secured to the body portion 64 of the coupling device 50, and extends upwardly towards the pulley wheel 52 that is rotatably mounted on an axle towards the top of the window jambs 22, 24 using an axle mounting plate 110 that is secured to each of the jamb channels 38, 40.

As best seen in Fig. 5, the other end of the sash cord 46 is attached to the lower sash 16 using a mounting plate 112, affixed to each of the side rails 30, 32 of the sash 16. In use, the mounting plate 112 on each side rail is concealed within the respective jamb channels 38, 40 of the side frame members 22, 24 of the window frame 12. Thus, the spring balance 48 is held between the lower edge of the window frame 12 and one end of the sash cord 46, by means of the coupling device 50. The spring balance 48 provides a resilient force which acts to balance the weight of the sash 16 at any vertical position within the window frame 12, thereby preventing the sash panel 16 from sliding to a closed position under the force of gravity.

The jamb channels 38, 40, each comprise an infill pane! 124a 124b, one face of which is most clearly visible on Fig. 3. The infill panels 124a, 124b each comprise a thin wooden pane! which is sized to fit over each of the jamb channels 38, 40. The infill pane! conceals all but the upper portion of the window balance system 44 from view when the window is installed. Specifically, only a portion of the sash cord 46 and pulley wheel 52 are visible in the upper half of the sash window assembly 10, as these are positioned on the outermost surface of each infill panel 124a, 124b. The lower half of the window balance system 44, namely that comprising the lower portion of the sash cord 46 and the spring balance 48 is positioned behind the innermost surface of each infili panel 124a, 124b and is therefore concealed from view behind the panels, when the window balance system 44 is installed.

The combination of visible sash cord 46 and pulley 52, combined with the concealed spring balance 48, provides the traditional appearance of a box-sash window, without the requirement for bulky box sash window frames and/or traditional cumbersome sash weights, with the easier and smoother sash panel movements afforded by a more contemporary spring balance assembly. This effect is achieved by combining the features of the two distinct traditional and contemporary systems, and arranging the features in a sash window assembly so as to selectively display the various features of the window balance system.

The invention is not restricted to the details of the foregoing embodiments.

For example, in one or more embodiments, the coupling device 50 may comprise a known balance shoe connector, or a known pivot shoe connector, or comprise a pivotal connector, and may or may not comprise a meta! support plate.

In embodiments comprising a pivot shoe connector or a connector having a pivotal mechanism, the lower end of each sash panel is connected to the pivotal connector of the coupling device by means of a pair of pivot bars, as is known in the field of tilting sash window arrangements. As with the above-described embodiment, the coupling device is arranged to slide in the jamb channels to allow the sash to be raised and lowered in the traditional manner, and is configured to couple one end of the sash connector with one end of the resilient means.

In such a further embodiment, the sash panel may comprise latches on either side or the upper part of the sash, to retain the sash panel within the jamb channel to facilitate sliding of the sash, when tilting of the sash is not required. The latches typically comprise elongate metal connectors, which are connected at one end to the first and second side sash rails 30, 32, respectively, and at the other end to the corresponding first and second side jambs 22, 24. The latches further comprise a locking means, adapted to move between a locked position in which the locking means is engaged with a receiving portion within each side jamb, and an unlocked position in which the locking means is retracted away from the receiving portion to aliow the upper part of the sash pane! to be released from the jamb channel and tilted away from the plane of the window frame. in one or more embodiments, a sash window assembly may comprise two window balance systems 44 in each of the side jambs 22,24; with one pair of window balance systems 44 operating movement of one of the sashes. This enables independent movement of both the upper and lower sashes 14, 16 within the window frame 12.

Claims (25)

1. A sash window assembly comprising: a window frame; a sash panel slidably mounted to the window frame; and a window balance system comprising: a resilient means, an elongate flexible sash connector connected at one end to the sash panel, and connected at the other end to the resilient means, and a pulley wheel mounted on the window frame around which the sash connector passes; wherein the sash connector and pulley wheel are at least partially exposed and the resilient means is concealed within the window frame.

2. A sash window assembly as claimed in claim 1, wherein the sash connector comprises one or more of a cord, a rope, a belt, a chain, a cable, and/ or wire.

3. A sash window assembly as claimed in claim 1 or claim 2, wherein the resilient means comprises a spring, or a spiral balance.

4. A sash window assembly as claimed in any preceding claim, wherein the pulley wheel is secured to an upper section of the window frame and the resilient means is secured to a lower section of the window frame.

5. A sash window assembly as claimed in any preceding claim, wherein the pulley wheel comprises a groove around its circumference, the groove being adapted to receive the sash connector and, optionally, wherein the pulley wheel is rotatably mounted on an axle or shaft, the axle or shaft being secured to the window frame.

6. A sash window assembly as claimed in claim 5, wherein the sash connector is adapted to run over the pulley wheel and within the groove.

7. A sash window assembly as claimed in any preceding claim, wherein at least one window balance system is positioned within a channel in one or more side frame members of the window frame.

8. A sash window assembly as claimed in any preceding claim, wherein the sash connector is attached to the resilient means via a coupling device.

9. A sash window assembly as claimed in claim 8, wherein the coupling device comprises a body portion and a support plate and, optionally, wherein the body portion comprises one or more channels for receiving one or more edges or side walls of the support plate, and optionally, wherein the support plate abuts at least a part of the body portion.

10. A sash window assembly as claimed in claim 9, wherein at least a part of the body portion comprises an aperture for disposing within an end of the sash connector.

11. A sash window assembiy as claimed in any of claims 10 to 13, wherein the body portion further comprises one or more apertures for receiving fastening means and, optionally, wherein at least one of the apertures for fastening means intersects the aperture for the sash connector,

12. A sash window assembly as claimed in claim 10 or claim 11, wherein the coupling device further comprises one or more fastening means and, optionally, wherein at least one of the fastening means comprises a screw thread.

13. A sash window assembly as claimed in claim 12, wherein the one or more fastening means secures the support plate to the body portion.

14. A sash window assembly as claimed in any of claims 9 to 13, wherein the support plate comprises a plurality of spaced apart grooves and, optionally, wherein at least one of the grooves is adapted to receive at least a part of the sash connector disposed within the aperture.

15. A sash window assembly as claimed in claim 14, wherein at least one of the apertures is arranged to overlie at least one of the grooves when the support plate is abutted against the body portion of the coupling device and, optionally, wherein at least one of the fastening means engages with at least a part of the sash connector disposed within one of the grooves.

16. A sash window assembly as claimed in any of claims 9 to 15, wherein the body portion further comprises one or more attachment points for connecting the resilient means and, optionally, wherein one or more of the attachment points comprise one or more of a channel, an anchor, a projection, a hook, and/ or a loop.

17. A sash window assembly as claimed in any of claims 9 to 16, wherein the coupling device comprises a pivotable component.

18. A sash window assembly as claimed in claim 17, wherein the coupling device comprises a pivot shoe.

19. A sash window assembly as claimed in claim 17 or claim 18, further comprising at least one window pivot bar and, optionally, wherein the at least one window pivot bar is attached at one end to one of the sash panels, and at the other end to the coupling device.

20. A coupling device for a sash window balance assembiy, the coupling device comprising a body portion and a support plate releasably connectable to the body portion, the coupling device adapted to receive one end of an elongate sash connector and having a portion connectable to a resilient means, wherein the body portion further comprises at least two apertures, the first aperture being adapted to receive the said one end of the sash connector and arranged in a first plane, and the second aperture being adapted to receive a fastener and arranged in a second plane, relative to the first aperture.

21. A coupling device as claimed in claim 20, wherein the body portion comprises one or more channels for receiving one or more side wails or edges of the support plate.

22. A coupling device as claimed in claim 20 or claim 21, further comprising one or more fastening means, wherein at least one of the fastening means is arranged to pierce a section of a sash connector positioned within the first aperture.

23. A coupling device as claimed in any of claims 20 to 22, wherein the support plate comprises one or more grooves across one or more of its edges and, optionally, wherein at least one of the grooves is adapted to receive a portion of a sash connector and, optionally, wherein at least one of the grooves is positioned below one of the apertures.

24. A coupling device as claimed in any of claims 20 to 23, wherein the support plate comprises metal.

25. A coupling device as claimed in any of claims 20 to 24, comprising a connector for receiving an end of a resilient means.