AU2014227553A1 - Double hung window assembly - Google Patents

Abstract

Abstract This invention relates to a double hung window assembly. The assembly includes a frame and a pair of counterbalanced sashes arranged within the frame. An operating mechanism is adapted to facilitate counterbalanced movement of the sashes between respective open and closed positions. A control means is operatively associated with the operating mechanism and adapted to enable movement of the operating mechanisms between a first position in which the sashes are in the respective closed positions and a venting position in which one of the sashes is moved relative to the other sash to provide a vent opening, whilst the other sash remains closed. Closed Position Open Position 'Fkc,0

Description

- 1 DOUBLE HUNG WINDOW ASSEMBLY Field of the invention [0001] This invention relates to door and window assemblies and in particular to double hung window assemblies. [0002] The invention has been developed primarily for use as a double hung window assembly for a sashless window (i.e. with frameless glazing panels) and will be described with reference to this particular application. However, it will be appreciated that the invention is not limited to this particular field of use. Background to the invention [0003] The following discussion of the prior art has been provided in order to place the invention in an appropriate technical context and allow the advantages of it to be more fully appreciated. However, any discussion of the prior art throughout the specification should in no way be considered as an admission that such prior art is widely known or forms part of common general knowledge in the field. [0004] Typical double hung windows include a handle located towards the bottom and about the midline of the lower pane. Such handles are provided to facilitate manual raising and lowering of the lower pane. Due to the prominent location in the centre of the lower pane, these handles necessarily obstruct the view through the lower pane. Also, if a user does not apply a vertical lifting or lowering force to the handle there can be a tendency for a turning force to be applied to the lower pane resulting in undesired friction against the frame making it more difficult, or in some cases impossible, to raise or lower the sash/pane. [0005] In addition, in known double hung windows a lock is commonly fitted to the outer frame to lock against the lower sash. However, the locks typically used for this purpose protrude from the frame to such an extent that they cannot be used with bi-fold panel windows or doors as the lock interferes with the panels. [0006] It is an object of the present invention to overcome or ameliorate one or more of the disadvantages of the prior art, or at least to provide a useful alternative.

-2 Summary of the invention [0007] According to the present invention, there is provided a double hung window assembly, including: a frame; a pair of sashes arranged within the frame, the pair of sashes including an upper sash and a lower sash; an operating mechanism for allowing counterbalanced movement of the upper and lower sashes between respective open and closed positions; a control means operatively associated with the operating mechanism, the control means being configured to enable movement of the operating mechanism between a first position in which the sashes are in the respective closed positions and a second position in which one of the upper and lower sashes is displaced relative to the other sash to a venting position, so as to provide a ventilation opening whilst the other sash remains closed. [0008] The following description will be made with reference to single glazed upper and lower sashes. However, it be appreciated that the present invention is not intended to be limited to this particular configuration, and could be readily used with a various glazing configurations, including double and triple glazed sashes, to provide the necessary insulating requirements for various building applications. [0009] Preferably, the upper sash is displaced by the movement of the operating member to the second position caused by the control means. The upper sash is preferably displaced downwardly from its closed position to its venting position by operation of the control means. Preferably, a reverse operation of the control means causes the operating mechanism to move to the first position and return the upper sash to its closed position. Advantageously, the lower sash is not displaced during displacement of the upper sash caused by movement of the control means between its first and second position (via operation of the operating mechanism), and remains in its closed position. [0010] The operating mechanism preferably includes a pulley and cord mechanism, wherein the cord is connected to the upper and lower sashes via the pulley. Preferably, the pulley and cord mechanism has a pulley wheel with a concaved outer surface which defines a track for the cord. In some embodiments, a single pulley and cord mechanism is used to connect the upper and lower sashes for counterbalanced -3 movement. In other preferred embodiments, the window assembly includes two pulley and cord mechanisms arranged at opposite edges of the sashes. It will be appreciated that the use of two pulley and cord mechanisms can assist in maintaining the alignment of the sashes during movement (i.e. they provide a resistance to any undesired tendency for the sashes to rotate relative to the frame during movement which would otherwise cause misalignment). The pulley wheel is preferably mounted adjacent to an upper edge of the upper sash. [0011] Preferably, the control means includes a lever system having a handle operatively connected to the pulley and cord mechanism. In some preferred embodiments, the handle is hingedly or pivotally mounted to the frame, and a connecting member extends between the handle to the pulley wheel, such that the handle can be selectively pivoted from a first position in which the pulley wheel is in an upper position and the upper sash is closed, and a second position wherein the pulley wheel is in a displaced lower position causing a corresponding displacement of the upper sash to its venting position to create the ventilation opening, as and when desired. Preferably, the connecting member is a connecting arm (e.g. a length of rod or tube). [0012] The proximal end of the connecting arm is preferably hingedly or pivotally connected to the handle. Preferably, the distal end of the connecting arm is attached, more preferably fixedly attached, to the pulley wheel such that movement of the connecting arm causes a corresponding movement of the pulley wheel. The pulley wheel is preferably mounted such that movement of the connecting arm causes a corresponding linear (e.g. vertical) upwards and downwards movement of the pulley wheel. [0013] Preferably, the pulley wheel is attached to the upper sash such that movement of the pulley wheel causes a corresponding movement of the upper sash. [0014] Preferably, the window assembly includes a locking means for locking the pair of sashes relative to the frame. The locking means is preferably adapted for movement between an unlocked configuration in which the pair of sashes are free to move in counterbalanced motion and a locked configuration in which it prevents or inhibits undesired counterbalanced movement between the sashes. The locking means preferably includes a key and barrel lock. Preferably, the key and barrel lock is -4 arranged within a handle, the handle being configured for selective manual hand operation to raise and lower the sashes as desired (when the lock is in the unlocked configuration). The handle and lock unit is preferably mounted to the lower sash. Preferably, the handle and lock unit is of a streamlined configuration such that the unit does not protrude excessively from the side frame component to which it is mounted. This streamline configuration advantageously enables the window assembly to be used with hinged and bi-fold door and window panels (both aluminium and timber) as the lock unit does not protrude to such an extent that it would interfere with panels of such hinged and bi-fold configurations when the panels are opened. In some preferred embodiments, the handle and lock unit has a maximum protrusion of about 19mm. [0015] In some preferred embodiments, the window assembly includes a latching means, the latching means being selectively operable for movement between a latching position in which the pair of sashes are free to move in counterbalanced motion and a latched position in which the latch prevents or inhibits undesired counterbalanced movement between the sashes. The latching means may be associated with the locking means. Preferably, the latching means includes a snib (or other lever-type member) and a latching member (e.g. hook or equivalent) connected to the snib such that movement of the snib causes a corresponding movement of the latching member between the latched and unlatched positions. The snib and latch are preferably adapted for rotational movement between the latched and unlatched positions. The latching means advantageously enables the pair of sashes to be latched against sliding counter-balanced movement simply by manual hand operation of the snib lever, without the requirement of using a key to lock the sashes. Should a more secure locking of the sashes be required, such as during extended periods of absence from a dwelling, the sashes be securely locked with the use of the key lock and barrel. [0016] Preferably, the (outer) frame is adapted to be readily mounted within an opening of a wall of a building. The opening may be formed in the wall framework of the building. In some preferred embodiments, the frame is adapted to be mounted to the wall framework in a snap-fitting manner. In such embodiments, the wall framework may be formed of (extruded) aluminium frame members having a receiving formation into which the frame (of the window assembly) can be mounted, preferably via a complementary joining element (e.g. by a snap fit). In other preferred forms, the wall framework can be formed of timber frame members and the frame (of the window assembly) can be fastened thereto by suitable fastening means (e.g. screws, nails, etc).

-5 [0017] The frame of the window assembly is preferably formed of a plurality of frame components. Preferably, the frame includes a pair of mutually opposed side edge components for locating and captively retaining the upper and lower sashes in predetermined spaced apart relation. In certain preferred embodiments, each side edge is preferably formed of three elongate components which are arranged in an overlying or layered manner, including an inner component, an outer component and an intermediate component arranged between the inner and outer components. Preferably, each frame component is formed by an extrusion method. The frame components can be formed of any suitable material such as, for example, aluminium. [0018] Preferably, the frame includes guide means for guiding the movement of the connecting member extending between the handle and the pulley wheel. The guide means preferably includes mutually opposed first and second guide portions, extending towards one another from the outer and intermediate frame components, respectively. Preferably, the first guide portion is integrally formed with the outer frame component as a one-piece unit (e.g. by extrusion). The second guide portion preferably is integrally formed with the intermediate frame component as a one-piece unit (e.g. by extrusion). Preferably, each guide portion is of a generally Y-shape, to thereby guide the connecting arm in a face-to-face manner during movement of the connecting member relative to the guide portions. [0019] Preferably, sash support elements are arranged within the side edge components of the frame. A first pair of mutually opposed sash support elements is preferably arranged within the side edge components of the frame for supporting the upper sash. A second pair of mutually opposed sash support elements is preferably arranged within the side edge components of the frame for supporting the lower sash. Preferably, the first pair of sash support elements is arranged between the respective outer and intermediate components of the side edges. The second pair of sash support elements is preferably arranged between the respective inner and intermediate components of the side edges. [0020] Each sash support element is preferably configured to extend along the length of the side of the sash which it is supporting. Preferably, each sash support element is generally U-shaped so that the edge of the sash can be securely retained within the support element, in tight fitting secure relation, such that the support elements and associated sash move together (effectively as a one-piece unit) relative to the side -6 edge components of the frame. The sash support elements are preferably arranged to act as a sash locator. It will be appreciated that the layered configuration of the frame components effectively locks the sash support elements within the frame. [0021] Preferably, the window assembly is a sashless design. That is, in certain embodiments, each of the upper and lower sashes includes a frameless glazing panel or pane. It will be appreciated that the sashless design advantageously enables a closer spacing (in a front to back direction) between the upper and lower sash, providing a streamlined configuration to the window assembly. In some embodiments, one or both of the upper and lower sashes may include side frame members, wherein the transversely extending edges (e.g. the horizontal edges for vertically moving sashes, or the vertical edges for horizontally moving sashes). In other embodiments, each of the upper and lower sashes is framed with a sash frame. In this context, it will be appreciated that the term "sash" is to be understood as a reference to a movable pane of the window assembly, which may be a framed sash (i.e. glazing pane plus sash frame) or a frameless sash (i.e. glazing panel without a sash frame). [0022] Preferably, a sealing element provided between the sash support element and the associated frame component. A sealing element is preferably arranged between the outer frame component and the respective sash support element. A sealing element is preferably arranged between the inner frame component and the respective sash support element. Each sealing element is preferably configured so as to be captively retained by a complementary shaped seal mount on the associated sash support element. Preferably, each sealing element has a base body adapted to be retained with the seal mount and a plurality fins extending from the base body to sealingly engage with the respective frame component. [0023] In some embodiments, the frame has a retaining formation for retaining a screen of the window assembly. Preferably, the retaining formation is formed, at least partially, in the outer component of the side edges. The retaining formation preferably extends along the entire length of the associated frame component. In some embodiments, the retaining formation is in the form of a groove, recess or other suitable cavity. Preferably, the retaining formation is formed by a substantially L-shaped extension extending from the associated frame component so as to define the groove. The screen is preferably a flyscreen sized to cover the open area of the window assembly.

-7 [0024] The operating mechanism preferably includes a pulley system about which the upper and lower sashes are counterbalanced. Preferably, the pulley system includes at least one pulley with an associated cable, the cable being connected (directly or indirectly) at its ends to the upper and lower sashes. In certain embodiments, the screen retaining formation is integrally formed with the associated frame component, thus avoiding the need for additional add-on sections to serve this function. [0025] Preferably, the pulley and cord mechanism includes an adjusting means for adjusting the effective length of the cord to facilitate alignment of the sashes relative to the frame. It will be appreciated that proper alignment of the sashes relative to the frame is important to ensure the sashes can track easily and smoothly, without undesirable resistance or jamming forces arising from misalignment. The adjusting means is preferably mounted to an associated sash supporting element. [0026] In one preferred embodiment, the adjusting means is associated with or incorporated into the pulley and cord system. Preferably, the pulley and cord system includes a pulley block support which is releasably or fixedly attachable to the connecting arm (e.g. the upper end). The pulley block support is preferably attachable to the connecting arm via an attaching arm. The attaching arm is preferably a threaded bar. Preferably, the attaching arm is threaded at both ends, one end for engaging the pulley block support and the other end for engaging the connecting arm. The pulley block support preferably has two receiving formations into which the threaded bar can be selectively attached to provide optional left- or right-hand mounting, as required. [0027] Preferably, the pulley is slidably mounted to the pulley block support such that the pulley is selectively slidable relative to the pulley block support to thereby adjust the effective length of the cord. In preferred embodiments, the sliding movement of the pulley is in a substantially vertical direction (either downwards or upwards) to lengthen or shorten the effective length of the cord. Preferably, the pulley support block has a central, substantially vertical slot along which the pulley is slidably mounted. [0028] The pulley is preferably connected to a displacement mechanism for controlling the displacement of the pulley, along the slot, relative to the pulley block support. In one preferred embodiment, the displacement mechanism includes a rack and gear mechanism (with matching tooth and pitch profiles). Preferably, the rack -8 includes a pair of mutually opposing rows of teeth, with the slot arranged in between. An adjustment member such as an adjustment screw connects the pulley and gear together, such that rotation of the screw causes a corresponding rotation of the gear to effect translational or linear displacement of the pulley along the slot, as desired. Preferably, a locking member (e.g. locking screw) is provided to lock the pulley in position relative to the pulley block support after adjustment. Preferably, the rack and pulley are arranged on opposite sides of the pulley block support. The adjustment mechanism preferably includes a backing plate to which the locking screw can threadingly engage. Preferably, the adjustment screw passes through a hole in the backing plate and threadingly engages an adjustment screw nut. [0029] It will be appreciated by those skilled in the art that the displacement mechanism advantageously functions to enable relatively small or fine adjustments to the effective length of the cord, and as well can be used to determine the extent of the displacement. In some embodiments, graduations or other suitable indicia can be arranged along the length of the slot and optionally a corresponding mark can be formed on the pulley such that the extent of displacement can be determined by reference to the graduations, or vice versa. [0030] In another embodiment, the adjusting means has a housing fixedly mounted to the sash supporting element and a slider, the slider being mounted for relative sliding movement within the housing. The slider is preferably (at least partially) housed within the housing and slidable relative thereto in a telescopic manner. Preferably, the adjusting means includes a locking screw for locking the slider relative to the housing, in the desired position to thereby set the effective length of the cord. [0031] In a second aspect of the invention, there is provided a method of assembling a window assembly according to the first aspect of the invention, the method including layer by layer steps in which the outer, intermediate and inner frame components are sequentially brought together in overlying relation. [0032] Preferably, the method of assembly includes the step of mounting the upper sash between the outer and intermediate frame components. The method of assembly preferably includes the step of mounting the lower sash between the inner and intermediate frame components.

-9 Brief description of the drawings [0033] A preferred embodiment of the invention will now be described, by way of example only, with reference to the accompanying drawings in which: [0034] Figures 1A and 1 B show the pair of counterbalanced sashes in the closed and venting positions, respectively; [0035] Figures 2A and 2B show perspective views of a portion of an embodiment of a double hung window assembly according to the invention; [0036] Figures 3A, 3B and 3C show a plan view of one side of the window assembly; [0037] Figure 4 shows detail of an integrally formed retaining groove for mounting a flyscreen to the window assembly; [0038] Figures 5A and 5B shows a side frame component snap-fit mounted to surrounding aluminium wall framework, and screw fastened to a surrounding timber wall framework, respectively; [0039] Figures 6A and 6B show an embodiment of the window assembly mounted to a hinged door rail, and a hinged door stile, respectively; [0040] Figure 7 shows a plan view of an embodiment of a slimline handle and lock unit of the window assembly; [0041] Figure 8 shows a plan view of a guide means positioned to guide the connecting member of the pulley and cord mechanism; [0042] Figures 9A and 9B show a plan view of a sash support element; [0043] Figures 1 OA, 1 OB and 10C show an adjusting means for adjusting the effective length of the cord of the pulley and cord mechanism; [0044] Figures 11 A, 11 B and 11C show another embodiment of an adjusting means for adjusting the effective length of the cord of the pulley and cord mechanism; and -10 [0045] Figures 12A, 12B and 12C show an embodiment of a latching mechanism of the window assembly. Detailed description of preferred embodiment [0046] Referring to the drawings, the invention provides a double hung window assembly 1 (Figures 2A-2B). The window assembly 1 includes an outer frame 2 having a pair of side edge components 3. A pair of frameless sashes, including a frameless upper sash 4 and a frameless lower sash 5, is slidably arranged for counterbalanced movement within the frame 2. That is, if one sash moves upwardly then the other sash will move downwardly, or vice versa. [0047] The following description will be made with reference to single glazed upper and lower sashes, formed of glass or acrylic glazing panels or panes, or other suitable materials for frameless panes. However, it be appreciated that the present invention is not intended to be limited to this particular configuration, and could be readily used with, for example, double and triple glazed sashes to provide the necessary insulating requirements for various building applications. [0048] As most clearly shown in Figures 1A and 1 B, the pair of sashes (4, 5) are mounted on an operating mechanism in the form a pulley wheel 6 and cord mechanism 7 to facilitate the counterbalanced movement of the upper and lower sashes between respective open and closed positions. [0049] For the sake of clarification, it will be noted that Figures 1A and 1 B show closed and ventilation positions of the sashes, respectively. As will be described in more detail below, the movement of the upper sash 4 to the ventilation position of Figure 1 B is achieved via a control means in the form of a cam lock device lever 8, and not via counterbalanced movement between the two sashes. That is, the lower sash 5 remains in its lower or closed position upon activation of the cam lock lever 8. [0050] The window assembly 1 includes two pulley and cord mechanisms (6, 7) arranged in a concealed position within the frame 2, at opposite edges of the sashes (4, 5). It will be appreciated that the use of two pulley and cord mechanisms assists in maintaining the alignment of the sashes during movement (i.e. they provide a resistance to any undesired tendency for the sashes (4, 5) to rotate relative to the frame 2 during movement which would otherwise cause misalignment).

- 11 [0051] The control means includes a lever system having a handle operatively connected to the pulley and cord mechanism. The handle 8 is hingedly or pivotally mounted to the frame and a connecting member in the form of a rod 9 extends between the handle to the pulley wheel 6. The handle 8 can be selectively pivoted from a first position (Figure 1A) in which the pulley wheel 6 is in an upper position and the upper sash 4 is closed, and a second position (Figure 1 B) in which the pulley wheel 6 is in a displaced lower position causing a corresponding displacement of the upper sash 4 to its venting position to create the ventilation opening. [0052] The proximal end of the connecting arm 9 is hingedly or pivotally connected to the handle 8. The distal end of the connecting arm 9 is attached to the pulley wheel 6 such that movement of the connecting arm causes a corresponding movement of the pulley wheel, such that movement of the connecting arm causes a corresponding linear (e.g. vertical) upwards and downwards movement of the pulley wheel. The displacement of the pulley wheel causes a corresponding movement of the upper sash. [0053] The window assembly 1 includes a locking means in the form of a key lock and barrel unit 10 (Figure 2A) for locking the pair of sashes (4, 5) relative to the frame 2. The locking unit 10 is adapted for movement between an unlocked configuration in which the pair of sashes (4, 5) are free to move in counterbalanced motion and a locked configuration in which the lock prevents undesired counterbalanced movement between the sashes. [0054] The key and barrel lock 10 is arranged within a handle 10' so as to provide a streamlined configuration to the window assembly 1, wherein the lock unit 10 and handle 10' does not protrude excessively from the side frame component to which it is mounted. This streamline configuration advantageously enables the window assembly to be used with hinged and bi-fold door and window panels (both aluminium and timber) as the lock unit does not protrude to such an extent that it would interfere with panels of such hinged and bi-fold configurations when the panels are opened. In the illustrated embodiment shown in Figure 7, the handle and lock unit has a maximum protrusion of about 19mm. [0055] In embodiment shown in Figures 12A to 12C, the window assembly includes a latching means in the form of a rotatable snib 11 and latching member. In the illustrated embodiment, the latching member (e.g. hook-type member) is an internal -12 member and cannot be seen in the drawings. The snib 11 is selectively operable for movement between an unlatched position (Figures 12A and 12B) in which the pair of sashes (4, 5) are free to move in counterbalanced motion and a latched position (Figure 12C) in which the latch prevents or inhibits undesired counterbalanced movement between the sashes. The latching means advantageously enables the pair of sashes to be latched against sliding counter-balanced movement simply by manual hand operation of the snib lever, without the requirement of using a key to lock the sashes. However, the latching means is preferably associated with the key and barrel lock 10 such that it can be unlocked/latched via the key. In addition, should a more secure locking of the sashes be required, such as during extended periods of absence from a dwelling, the sashes be securely locked with the use of the key lock and barrel. [0056] As most clearly shown in Figures 5A and 5B, the frame is adapted to be readily mounted within an opening of a wall of a building. In Figure 5A, the frame 2 is adapted to be mounted to extruded aluminium wall framework 12 in a snap-fitting manner. In this embodiment, the aluminium frame member 12 has a receiving formation 13 into which the frame 2 (of the window assembly 1) can be mounted, via a complementary joining element 14 (e.g. by a snap or press fit). In the embodiment of Figure 5B, the wall framework can be formed of timber frame members 15 and the frame 2 (of the window assembly 1) can be fastened thereto by suitable fastening means (e.g. screws, nails, etc). [0057] As most clearly shown in Figures 3C and 3F, the outer frame 2 of the window assembly 1 is preferably formed of a plurality of frame components. The frame 2 includes a pair of mutually opposed side edge components 16 for locating and captively retaining the upper and lower sashes (4, 5) in predetermined spaced apart relation. Each side edge is formed of three elongate components which are arranged in an overlying or layered manner, including an inner component 17, an outer component 18 and an intermediate component 19 arranged between the inner and outer components. [0058] Referring to Figure 8, the frame 2 includes guide means for guiding the movement of the connecting member extending between the handle 8 and the pulley wheel 6. The guide means includes mutually opposed generally Y-shaped first and second guide portions 20, extending towards one another from the outer and intermediate frame components, respectively. The first guide portion 20 is integrally formed with the outer frame component 18 as a one-piece unit. The second guide -13 portion 20 is integrally formed with the intermediate frame component 19 as a one-piece unit. Each guide portion 20 is of a generally Y-shape to thereby guide the connecting arm in a face-to-face manner during movement of the connecting member 9 relative to the guide portions 20. [0059] Referring to Figures 9A and 9B, the window assembly 1 includes sash support elements arranged within the side edge components 16 of the frame 2. A first pair of mutually opposed sash support elements 21 is arranged within the side edge components of the frame 2 for supporting the upper sash 4. A second pair of mutually opposed sash support elements 22 is arranged within the side edge components of the frame 2 for supporting the lower sash 5. The first pair of sash support elements 21 is arranged between the respective outer 18 and intermediate components 19 of the side edges. The second pair of sash support elements 22 is arranged between the respective inner 17 and intermediate 19 components of the side edges. [0060] Each sash support element (21, 22) is preferably configured to extend along the length of the side of the sash (i.e. pane) which it is supporting, and is generally U shaped so that the edge of the sash can be securely retained within the support element, in tight fitting secure relation, such that the support elements and associated sash move together (effectively as a one-piece unit) relative to the side edge components of the frame. It will be appreciated that the layered configuration of the frame components effectively locks the sash support elements within the frame. [0061] As most clearly shown in Figures 2A and 2B, the window assembly 1 is a sashless design, wherein each of the upper and lower sashes includes a frameless glazing panel or pane such that the horizontal edges of each sash/pane (4, 5) are exposed. It will be appreciated that the sashless design advantageously enables a closer spacing (in a front to back direction) between the upper and lower sash, providing a streamlined configuration to the window assembly. [0062] With reference to Figure 9B, a sealing element 23 is provided between the sash support element and the associated frame component. One sealing element 23 is arranged between the outer frame component and the respective sash support element. A second sealing element 23 is arranged between the inner frame component and the respective sash support element. Each sealing element 23 is configured so as to be captively retained by a complementary shaped seal mount groove or slot 24 on the -14 associated sash support element. Each sealing element 23 has a base body 25 adapted to be retained within the seal mount and a plurality fins 26 (i.e. brush-type seal) extending from the base body 25 to sealingly engage with the respective frame component. [0063] In some embodiments, as shown in Figure 4, the frame 2 has a retaining formation 27 for retaining a screen of the window assembly 1. The retaining formation 27 is formed in the outer component of the side edges and extends along the entire length of the associated frame component to form of a groove, recess or other suitable cavity 28 for retaining a flyscreen (not shown) sized to cover the open area of the window assembly. [0064] Referring to Figures 10A, 1OB and 10C, the pulley and cord mechanism includes an adjusting means 30 for adjusting the effective length of the cord 7 to facilitate alignment of the sashes (4, 5) relative to the frame 2. It will be appreciated that proper alignment of the sashes/panes (4, 5) relative to the frame 2 is important to ensure the sashes can track easily and smoothly, without undesirable resistance or jamming forces arising from misalignment. [0065] In embodiment of Figures 10A, 1OB and 10C, the adjusting means 30 is associated with or incorporated into the pulley 6 and cord 7 system. The pulley and cord system includes a pulley block support 31 which is attachable to the upper end of the connecting arm 9 via an attaching arm 32. The attaching arm 32 is preferably a threaded bar. As most clearly shown in Figure 10C, the pulley block support 31 has two receiving formations in the form of threaded holes 33 into which one end of the threaded bar can be selectively attached to provide the option for left- or right-hand mounting, as required. [0066] The pulley 6 is slidably mounted to the pulley block support 31 such that movement of the pulley 6, either downwards or upwards, relative to the pulley block support 31 lengthens or shortens the effective length of the cord 7. To facilitate this sliding movement, the pulley support block 31 has a central, substantially vertical slot 34 adjacent to which the pulley 6 is mounted (see Figure 1OB). [0067] The pulley 6 is connected to a displacement mechanism for controlling the displacement of the pulley, along the slot 34, relative to the pulley block support 31. In -15 the embodiment of Figures 1 OA to 10C, the displacement mechanism includes a rack 35 and gear 36 mechanism arranged on the opposite side of the pulley block support to the pulley6. The rack 35 includes a pair of mutually opposing rows of teeth, with the slot being arranged between the rows of teeth. [0068] An adjustment member in the form of an adjustment screw 37 connects the pulley 6 and gear 36 together, such that rotation of the screw 37 causes a corresponding rotation of the gear 36 to effect linear displacement of the pulley 6 along the slot 34, as required to adjust the effective length of the cord 7. A locking member in the form of a locking screw 38 is provided to lock the pulley 6 in position relative to the pulley block support 31 after adjustment. As most clearly seen in Figure 1 OA, the rack 35 and pulley 6 are arranged on opposite sides of the pulley block support 31. The adjustment mechanism includes a backing plate 39 to which the locking screw 38 can threadingly engage. The adjustment screw 37 passes through a hole 40 in the backing plate 39 and threadingly engages an adjustment screw nut 41. [0069] It will be appreciated by those skilled in the art that the gear and rack displacement mechanism advantageously functions to enable relatively small or fine adjustments to the effective length of the cord. In addition, the gear and rack mechanism can be used to facilitate measured displacement through the optional use of appropriate graduations (not shown) on the pulley block support and/or pulley block to provide a visual indication of the extent of the displacement. [0070] Figures 11 A, 11 B and 11C show an alternative embodiment of the adjusting means 30 for adjusting the effective length of the cord to facilitate alignment of the sashes relative to the frame. In this embodiment, the adjusting means has a housing 42 fixedly mounted to the sash supporting element (21, 22) and a telescopically received slider 43, mounted for relative sliding movement within the housing 42. The adjusting means 30 includes an adjusting screw 44 for adjusting the position of the slider 43 relative to the housing 42, thereby setting the effective length of the cord 7. That is, rotation of the adjusting screw 44 causes linear movement of the screw in a direction generally parallel to the longitudinal axis of the housing to effect a corresponding movement of the slider [0071] Accordingly, the present invention, at least in its preferred embodiments, provides a double hung window assembly 1 which is advantageously adapted to enable -16 its top sash 4 to move to an open position independently of its lower sash 5, thus providing a ventilation opening whilst retaining the security of a locked window. The window assembly can be used in the conventional manner when it is desired to open the window. In these and other respects, the invention in its preferred embodiments, represents a practical and commercially significant improvement over the prior art. [0072] Although the invention has been described with reference to specific examples it will be appreciated by those skilled in the art that the invention may be embodied in many other forms.

Claims (38)

1. A double hung window assembly, including: a frame; a pair of sashes arranged within the frame, the pair of sashes including an upper sash and a lower sash; an operating mechanism for allowing counterbalanced movement of the upper and lower sashes between respective open and closed positions; a control means operatively associated with the operating mechanism, the control means being configured to enable movement of the operating mechanism between a first position in which the sashes are in the respective closed positions and a second position in which one of the upper and lower sashes is displaced relative to the other sash to a venting position, so as to provide a ventilation opening whilst the other sash remains closed.

2. A double hung window assembly according to claim 1, wherein the upper sash is displaced by the movement of the operating member to the second position caused by the control means.

3. A double hung window assembly according to claim 2, wherein the upper sash is displaced downwardly from its closed position to its venting position by operation of the control means.

4. A double hung window assembly according to any one of the preceding claims, wherein the operating mechanism includes a pulley and cord mechanism, wherein the cord is connected to the upper and lower sashes via the pulley.

5. A double hung window assembly according to any one of the preceding claims, wherein the control means includes a lever system having a handle operatively connected to the pulley and cord mechanism, the handle being hingedly mounted to the frame, and a connecting member extending between the handle to the pulley wheel, such that the handle can be selectively pivoted from a first position in which the pulley wheel is in an upper position and the upper sash is closed, and a second position wherein the pulley wheel is in a displaced lower position causing a corresponding displacement of the upper sash to its venting position to create the ventilation opening. -18

6. A double hung window assembly according to claim 5, wherein the connecting member is a connecting arm and the proximal end of the connecting arm is pivotally connected to the handle, and the distal end of the connecting arm is attached to the pulley wheel such that movement of the connecting arm causes a corresponding movement of the pulley wheel.

7. A double hung window assembly according to claim 5 or claim 6, wherein the pulley wheel is mounted such that movement of the connecting arm causes a corresponding substantially linear upwards and downwards movement of the pulley wheel.

8. A double hung window assembly according to any one of claims 5 to 7, wherein the pulley wheel is attached to the upper sash such that movement of the pulley wheel causes a corresponding movement of the upper sash.

9. A double hung window assembly according to any one of claims 6 to 8, including a locking means for locking the pair of sashes relative to the frame.

10. A double hung window assembly according to claim 9, wherein the locking means is adapted for movement between an unlocked configuration in which the pair of sashes are free to move in counterbalanced motion and a locked configuration in which the locking means substantially prevents undesired counterbalanced movement between the sashes.

11. A double hung window assembly according to claim 9 or claim 10, wherein the locking means includes a key and barrel lock.

12. A double hung window assembly according to claim 11, wherein the key and barrel lock is arranged within a handle, the handle being configured for selective manual hand-operation to raise and lower the sashes as desired.

13. A double hung window assembly according to claim 12, wherein the handle and lock unit is mounted to the lower sash.

14. A double hung window assembly according to any one of claims 5 to 13, including a latching means selectively operable for movement between a latching position in which the pair of sashes are free to move in counterbalanced motion and a -19 latched position in which the latch prevents or inhibits undesired counterbalanced movement between the sashes.

15. A double hung window assembly according to claim 14, wherein the latching means includes a snib and a latching member connected to the snib such that movement of the snib causes a corresponding movement of the latching member between the latched and unlatched positions.

16. A double hung window assembly according to claim 14 or claim 15, wherein the snib and the latch are adapted for rotational movement between the latched and unlatched positions.

17. A double hung window assembly according to any one of claims 5 to 16, wherein the frame is formed of a plurality of frame components, including a pair of mutually opposed side edge components for locating and captively retaining the upper and lower sashes in predetermined spaced apart relation.

18. A double hung window assembly according to claim 17, wherein each side edge is formed of three elongate components which are arranged in a layered manner, including an inner component, an outer component and an intermediate component arranged between the inner and outer components.

19. A double hung window assembly according to claim 17 or claim 18, wherein the frame includes a guide means for guiding the movement of the connecting member.

20. A double hung window assembly according to claim 19, wherein the guide means includes mutually opposed first and second guide portions, the first and second guide portions extending towards one another from the outer and intermediate frame components, respectively.

21. A double hung window assembly according to any one of claims 17 to 20, wherein sash support elements are arranged within the side edge components of the frame, the sash support elements including a first pair of mutually opposed sash support elements arranged within the side edge components of the frame for supporting the upper sash, and a second pair of mutually opposed sash support elements arranged within the side edge components of the frame for supporting the lower sash. - 20

22. A double hung window assembly according to claim 21, wherein the first pair of sash support elements is arranged between the respective outer and intermediate components of the side edges, and the second pair of sash support elements is arranged between the respective inner and intermediate components of the side edges.

23. A double hung window assembly according to claim 21 or claim 22, wherein each of the upper and lower sashes includes a frameless glazing panel.

24. A double hung window assembly according to claim 23, wherein one or more sealing elements are provided between respective frame components.

25. A double hung window assembly according to claim 24, wherein the frame has a retaining formation for retaining a flyscreen.

26. A double hung window assembly according to any one of claims 17 to 25, wherein the operating mechanism includes a pulley and cord system about which the upper and lower sashes are counterbalanced, the pulley and cord system having at least one pulley with an associated cord, the cord being connected at its respective ends to the upper and lower sashes.

27. A double hung window assembly according to claim 26, wherein the pulley and cord system have an adjusting means for adjusting the effective length of the cord to facilitate alignment of the sashes relative to the frame.

28. A double hung window assembly according to claim 27, wherein the adjusting means is associated with the pulley and cord system.

29. A double hung window assembly according to claim 28, wherein the pulley and cord system includes a pulley block support which is attachable to the connecting arm via an attaching arm.

30. A double hung window assembly according to claim 29, wherein the pulley is slidably mounted to the pulley block support such that the pulley is selectively slidable relative to the pulley block support to thereby adjust the effective length of the cord. - 21

31. A double hung window assembly according to claim 30, wherein the pulley support block has a central, substantially vertical slot along which the pulley is slidably mounted.

32. A double hung window assembly according to claim 31, wherein the pulley is connected to a displacement mechanism for controlling the displacement of the pulley, along the slot, relative to the pulley block support.

33. A double hung window assembly according to claim 32, wherein the displacement mechanism includes a rack and gear mechanism.

34. A double hung window assembly according to claim 33, wherein the rack includes a pair of mutually opposing rows of teeth, with the slot arranged in between.

35. A double hung window assembly according to claim 34, wherein an adjustment member such as an adjustment screw connects the pulley and gear together, such that rotation of the screw causes a corresponding rotation of the gear to effect translational or linear displacement of the pulley along the slot.

36. A double hung window assembly according to claim 35, wherein a locking member is provided to lock the pulley in position relative to the pulley block support after adjustment.

37. A method of assembling a window assembly according to any one of the preceding claims, the method including layer by layer steps in which the outer, intermediate and inner frame components are sequentially brought together in overlying relation.

38. A double hung window assembly substantially as herein described with reference to any one of the embodiments of the invention illustrated in the accompanying drawings and/or examples.