GB2488366A

GB2488366A - Sash window and counterbalance

Info

Publication number: GB2488366A
Application number: GB1103355.2A
Authority: GB
Inventors: Damian Rowe
Original assignee: R J PARRY Ltd
Current assignee: R J PARRY Ltd
Priority date: 2011-02-28
Filing date: 2011-02-28
Publication date: 2012-08-29
Also published as: GB201103355D0

Abstract

A sash window comprising: a frame containing first and second window sashes disposed parallel to a window plane, the first sash being slidable relative to the second window sash; a pulley 45 attached to the frame; and resilient means 50 such as a spring, wherein the first sash is connected to resilient means via the pulley. Preferably the resilient means is a torsion spring fixed at 51 and rotationally coupled to a helical bar 56 which is mounted via guide block 58 for sliding movement; the helical bar is prevented from rotational movement such that axial sliding of the helical bar in response to opening and closing the window rotates the spring.

Description

SASH WINDOW

Field of Invention

This invention relates to a sash window

Background to the Invention

Sash windows are well known. A sash window comprises one or more movable panels or "sashes" that form a frame to hold panes of glass or sheets of transparent material. Although any window with this style of glazing is technically "a sash", the term is used almost exclusively to refer to windows where the sashes are, in the closed position, arranged in a vertical plane and opened by sliding vertically, or horizontally, with respect to each other.

The name "hung sash window" typically refers to a double hung window with two sashes that can move up and down in the window frame. A single hung window has two sashes but normally the top sash is fixed and only the bottom sash slides. Triple and quadruple hung windows are used for tall openings.

To facilitate operation, the weight of the sash may be balanced by a heavy steel, lead, or cast iron sash weight or counter-weight. The sash weight is connected to the window by a sash cord or chain that runs over a pulley at the top of the frame. The weights are typically arranged to travel up and down in a box concealed within the window frame (hence the conventional name "Box Sash Window"). A dividing strip is often suspended within the box to prevent collision of the weights.

Sash weights are normally required to be heavy (in order to counter-balance the weight of a sash) and, as a result, are typically large and bulky in size. Accordingly, a typical box for concealing a sash weight will also need to be large and bulky. This can be problematic where predetermined requirements restrict the available space for a sash window and/or its frame.

Summary of the invention

Proposed is a sash window that retains the appearance of a traditional pulley-operated sash window whilst removing the need for a large, bulky box for housing a pulley arrangement.

According to an aspect of the invention there is provided a sash window comprising: a frame containing first and second window sashes disposed parallel to a window plane, the first sash being slidable relative to the second window sash; a pulley attached to the frame; and resilient means, wherein the first sash is connected to resilient means via the pulley.

The pulley and the resilient means may be encased within the frame body.

The pulley may comprise: a pulley wheel rotatably supported on axle or shaft; and a rope, cable, belt, or chain which usually runs over the wheel. The pulley wheel may have a groove between two flanges around its circumference, in which case the rope, cable, belt, or chain may be adapted to run over the wheel and inside the groove.

The connecting means may be connected to the resilient means via a helical bar, wherein the helical bar is adapted to engage with the resilient means so as to translate vertical movement of the helical bar into rotational movement of the resilient means. Furthermore, the rotational movement of one end of the resilient means may be adapted to be restricted or prevented.

Proposed embodiments retain the traditional characteristics of a conventional pulley-operated sash window whilst reducing the space requirements of the frame by removing the need for a bulky sash weight.

Brief description of the drawings

Examples of the invention will now be described in detail with reference to the accompanying drawings, in which: Figures 1 is a front elevation of a sash window according to an embodiment of the invention; and Figure 2 is a close up illustration of the right hand side of the sash window of Figure 1, wherein a front of the side member 13 has been removed to expose its interior; Figure 3A is a side elevation of the pulley and spring arrangement used inside the side member of Figure 1; Figure 3B is a cross sectional view taken along the line A-A in Figure 3A; and Figures 4A and 4B show a modification to the pulley and spring arrangement of Figures 3A and 3B.

Detailed description

The same reference numbers have been used in different figures to denote the same or similar features.

Figure 1 is a front elevation of a sash window according to an embodiment of the invention. The sash window 1 is installed in an opening in the exterior wall of a building, such as a house, for separating an interior space and an exterior space of the building.

The sash window 1 has a frame 10 having an upper sash 20 and a lower sash 30 supported therein. The frame 10 is rectangular and comprises a head member 11, a sill member 12 and a pair of side members 13, 13.

The upper and lower sashes 20 and 30 each hold a glazing panel (i.e. single or double glazing) 24, 34 disposed side-by-side or in horizontal juxtaposition with each other.

The upper sash 20 and the lower sash 30 are offset from each other in a depth direction of the window I (i.e., in a direction perpendicular to a general plane of the window 1), with the upper sash 20 disposed on an exterior side of the sash window 1 and with the lower sash 30 disposed on an interior side of thewindowl.

in this example, the lower sash 30 is supported and guided by the side members 13 of the frame 10 for vertical sliding movement along the side members 13 to open and close the window I in a conventional fashion, whereas the upper sash 20 is fixed in position by the head member 11 and jamb members 13 of the frame 10. In other words, the sash window is the single hung' type.

In an alternative embodiment, both the upper sash 20 and the lower sashes 30 may be supported and guided by the jamb members 13 of the frame 10 for vertical sliding movement along the jamb members 13 to open and close the window 1 in a conventional fashion. Such an embodiment is a double-hung' type.

Other embodiments may further include a movable or fixed wire screen disposed within the frame 10 at an exterior side thereof. The screen may be omitted as appropriate. Embodiments may further include a fixed or movable blind disposed on the interior side of the inner or outer frame.

In Figure 1, the single-hung sash window 1 is in a fully closed state when the lower sash 20 is a lower limit position of vertical movement. In this state, the bottom rail (outer meeting rail) 38 of the upper sash 20 and the top rail (inner meeting rail) 40 of the lower sash 30 are overlapped in the depth direction of the window 1.

is The top rail 40 of the lower sash 30 may have a crescent lock (not shown), and the bottom rail 38 of the upper sash 20 may have a crescent keeper (not shown) so that when the crescent lock is engaged with the crescent keeper with the upper and lower sashes 20 and 30 placed in a closed state, the upper 20 and lower 30 sashes are locked in position within theframelO.

Turning to Figure 2, a close up illustration of the right hand side of the sash window of Figure 1 is shown, wherein a front of the side member 13 has been removed to expose the inside of the side member 13.

A circular pulley wheel 45 is rotatably supported on axle or shaft which is attached to the inside upper end of the side member 13, and an elongate rigid tube 47 is fixed to the inside lower end of the side member 13. Here, the rigid tube 47 is shown as being transparent so that its internal volume is visible within the illustration of Figure 2.

Resilient means, in this example a spring 50, are provided inside the rigid tube 47. A bottom end 51 of the spring 50 is fixed to the internal surface of the rigid tube 47 so that the bottom end 51 of the spring 50 cannot move relative to the rigid tube 47. The other (top) end 52 of the spring 50 is connected to a connecting block 54 (provided inside the rigid tube 47) so that the top end 52 of the spring 50 cannot move relative to the connecting block 54. The connecting block, however, is adapted to maintain a fixed position at the end of the rigid tube 47 and so that it can rotate about the longitudinal axis of the rigid tube 47. In this way, the connecting block 54 may be used to twist and compress/decompress the spring 50 within the rigid tube 47.

The connecting block 54 is provided with slot (or rectangular aperture), not shown, extending vertically through it (i.e. from its upper surface to its lower surface) so that a bar 56 can pass through the connecting block 54 in a vertical direction (i.e. along the longitudinal axis of the tube 47 and side member 13).

A helical bar 56, in other words, a bar 56 that has been twisted about its central longitundinal axis to form a helical shape, is provided within the side member 13 and passes through the slot of the connecting block 54. Here, the cross-sectional shape of the helical bar is rectangular and matches that of the slot formed in the connecting block 54. The helical bar 56 therefore closely fits within the slot and, as the helical bar 56 moves through the slot, the connecting block 54 rotates about the central axis of the helical bar 56.

The top end 57 of the helical bar 56 is attached to a guide block 58 so that the helical bar 56 cannot move relative to the guide block 58. The guide block 58 is also attached to one end of a cable 55 which runs over the pulley wheel 45 and is attached to the lower sash 30 at the other end of the cable 55.

The guide block 58 is arranged to slide up and down (i.e. vertically), guided by a pair of ball bearings 60 (provided in the guide block) arranged to run along grooved channels 62 provided in the side member 13. Thus, the guide block 58 (and connected helical bar 56) is prevented from rotating by the engagement of the pair of ball bearings 60 and the grooved channels 62.

Thus, rotation of the helical bar 56 about the vertical axis is restricted or prevented.

The pulley wheel 45 may have a groove between two flanges around its circumference, in which case the cable 55 may be adapted to run over the wheel 45 and inside the groove.

Thus, it will be understood that the lower sash 30 is connected to the spring 50 via the pulley arrangement. Further, the pulley wheel 45, the helical bar 56 and the spring 50 are encased within the side member 13 of the frame in a similar fashion to a conventional pulley and sash weight arrangement.

Accordingly, it will be appreciated that the embodiment of Figure 1 and 2 has the same external appearance as a conventional pulley-operated sash window. However, unlike a conventional pulley-operated sash window, the embodiment of Figures 1 and 2 does not use a bulky weight to counter-balance the weight of the lower sash 30.

To Instead, vertical movement of the sash window causes a corresponding vertical movement of the helical bar 56 which, in turn, passes vertically through the connecting block 54 and causes the connecting block to rotate about the vertical axis. Rotation of the connecting block 54 twists the top end 52 of the spring 50 causing it to compress/decompress within the rigid tube 47. The twisting of the spring, and its resultant compression or decompression provides a resilient forces which acts to balance the weight of the sash window and hold the sash window at any vertical position, thereby preventing the sash window from sliding to a closed position under the force of gravity.

In words, the lower sash 30 is connected to resilient means via the pulley and the resilient means is adapted to provide a force which opposes the force of gravity acting upon the sash.

The helical bar and spring arrangement is fitted into the side member 13 where it is out of sight (from an external viewer).

Figures 3A and 3B illustrate a side elevation and cross-sectional view (along the line A-A), respectively, of the pulley and spring arrangement used inside the side member 13 of Figure 1. Here, it can be seen that the ball bearings 60 of the guide block 52 closely fit inside channels 62 50 as to be restricted to motion along a single axis (defined by the longitudinal direction of the guide channels). The close fit also restricts rotation of the guide block 58 about this axis, therefore also preventing rotation of the helical bar 56 as it passes through the connecting block 54 (and causes the connecting block 54 to rotate).

It will be appreciated that a pulley and spring arrangement can have a much slimmer profile than a conventional sash weight. Accordingly, it can be fitted into sash window side members having smaller internal dimensions than that required to house a conventional pulley and sash weight arrangement.

Embodiments may therefore retain the traditional visual appearance of a conventional pulley-operated sash window whilst reducing the space requirements of the frame by reducing the required size of the side member.

Various modifications may be made to the embodiments described above without departing from the scope of the invention. For example, as shown in Figures 4A and 4B, the guide block may comprise further ball bearing (such as an extra pair of ball bearings as shown). Also, other suitable connecting means may be arranged to run over the pulley wheel and connect the window sash to the spring, such as a rope, belt or chain for example.

Claims

Claims 1. A sash window comprising: a frame containing first and second window sashes disposed parallel to a window plane, the first sash being slidable relative to the second window sash; a pulley attached to the frame; and resilient means, wherein the first sash is connected to resilient means via the pulley.
2. The sash window of claim 1, wherein the pulley and the resilient means are housed inside the body of the frame.
3. The sash window of claim 1 or 2, wherein the resilient means comprise a spring.
4. The sash window of any preceding claim, wherein the pulley comprises: a pulley wheel rotatably supported on an axle; and connecting means adapted to run over the pulley wheel and to connect the first sash to the resilient means.
5. The sash window of claim 4, wherein the pulley wheel comprises a groove around its circumference, and wherein the connecting means comprise at least one of: a rope; a cable; a belt; and a chain adapted to run over the wheel and inside the groove.
6. A sash window according to claim 4 or 5 wherein the connecting means are connected to the resilient means via a helical bar, the helical bar being adapted to engage with the resilient means so as to translate vertical movement of the helical bar into rotational movement of the resilient means.
7. A sash window according to claim 6, wherein rotational movement of one end of the resilient means is adapted to be prevented.
8. A sash window substantially a described hereinbefore with reference to the accompanying figures