AU2009217484A8

AU2009217484A8 - A Casement Window Closure System

Info

Publication number: AU2009217484A8
Application number: AU2009217484A
Authority: AU
Inventors: David Peter Forrestal; Alexander Neal Rycroft
Original assignee: Assa Abloy Australia Pty Ltd
Current assignee: Assa Abloy Australia Pty Ltd
Priority date: 2008-09-24
Filing date: 2009-09-24
Publication date: 2014-10-02
Anticipated expiration: 2029-09-24
Also published as: AU2009217484A1; AU2009217484B2; NZ579897A

Abstract

A cranking assembly for operating a window including a rotatable handle assemble able to pivot into a low profile storage position, a gear transmission assembly, a pair of hingedly interconnected arms connected to a drive unit with an extendible member coupled to one of the interconnected arms by a cam and cam follower in cooperation.

Description

A CASEMENT WINDOW CLOSURE SYSTEM FIELD OF THE INVENTION The present invention relates to casement windows, and in particular to systems for 5 operating (e.g. opening, closing, locking, unlocking etc) casement windows. BACKGROUND A casement window (occasionally referred to as simply a "casement") is a window with a sash that is attached to the window frame by one or more hinges, and which 10 opens by swinging in or out. Casement windows are most typically "side-hung" (where a vertical sides edge of the sash attaches to one of the vertical side edges of the window frame), although they can also be "top-hung" (hinged along the top horizontal edge) or even occasionally "bottom-hung" (hinged along the lower horizontal edge). Casement windows can be used singly, or in pairs, within a common frame. 15 In recent times, many casement window operating systems have been provided in which the sash is opened and closed using a winding handle (also called a "crank handle" or simply a "crank"), which in turn operates an opening and closing mechanism. 20 A typical casement window includes a sash and a frame. The sash typically has a pane of glass (or some other glazing) so that it is possible to see through the window when the window is closed. The sash is most commonly side-hung to the frame via stays or hinges. A crank handle is mounted to the frame together with the associated 25 operating mechanism which opens/closes the sash when the crank handle is turned. Whilst conventional casement windows are widely used and generally successful, they nevertheless suffer from certain shortcomings. One such shortcoming relates to the rate of closure of the sash relative to the winding of the crank. In most existing 30 casement window operating systems, turning the crank handle causes rotation of a threaded rod. The rotation of the threaded rod in turn typically operates a pair of "scissor"-type operating members which extend between the crank handle unit (which typically contains the threaded rod) and the window sash. The operating members push the window sash open or pull it closed, depending on which way the crank 2 handle is turned. It would be desirable if the operator of the handle was afforded a mechanical advantage as the sash comes into sealing closure with the frame, however this is not generally the case with prior art casement window closure systems. 5 Another problem commonly associated with conventional casement window operating systems arises because the unit which houses the crank handle, and the associated sash opening/closing mechanism (i.e. the operating members etc), are typically mounted on/near/along the lower horizontal edge of the window frame. This is especially so for side-hung casement windows. With side-hung casement windows, 10 one vertical side edge of the window sash connects to a vertical sides edge of the window frame meaning that there is no room for the crank handle unit and associated operating mechanism (e.g. the "scissor"-type operating members etc) to be mounted on the side edge of the window. Consequently, with these conventional systems, the lower horizontal edge of the window frame is the only convenient place where the 15 crank handle unit etc can be mounted. Additionally they are not placed on the top horizontal member of the frame because users would not be able to reach it on high windows. In this position, the crank handle unit and associated mechanism(s) are exposed and susceptible to collecting water, dust and the like which can lead to corrosion, increased wear and the like which can in turn adversely affect the longevity 20 of the operating system or parts thereof. Another shortcoming of many conventional casement window operating systems is that the crank handle permanently protrudes out from the crank handle unit (which itself is often a bulky unit mounted to the window frame), and this can be unsightly 25 and detract from the overall aesthetic of the casement window. This can be a significant problem because windows and the appearance of the surrounding frame etc are increasingly viewed and used as an important aesthetic feature of a room or indoor area. 30 With regards to conventional mechanisms used to lock casement windows, a number of different mechanisms have previously been proposed. In some cases, the mechanism comprises a simple key lock, snib button or the like which forms part of the crank handle unit and operates to prevent rotation of the crank handle. These systems have the benefit of being relatively unobtrusive, or at least little more 3 obtrusive than the main crank handle unit, because they are typically incorporated into the crank handle unit. However, locking mechanisms such as this are generally considered less secure because they do not actually secure the window sash to the window frame - they simply lock the crank handle against rotation thereby indirectly 5 preventing opening of the window. It can still be possible to prise/force the window open, even if this means causing deformation/damage to the locked crank handle unit. Therefore, these locking mechanisms may provide significantly less security than alternative mechanisms which operate to directly secure the window sash to the window frame. Whilst these alternative mechanisms which directly secure the 10 window sash to the frame may provide a greater level of security, they are typically separate mechanisms from the crank handle unit, and they are often mounted on a separate area of the window frame, and this can be particularly unsightly. It will be understood that side-hung casement windows may have the sash hingedly 15 mounted to the left-hand side vertical edge of the window frame, or to the right-hand side vertical edge of the window frame. In this specification, side-hung casement windows which have the sash hinged to the left-hand side vertical edge of the window frame (when viewed from inside the window) will be referred to as "left-handed", and likewise side-hung casement windows which have the sash hinged to the right-hand 20 side vertical edge of the window frame (when viewed from inside the window) will be referred to as " right-hand". A further shortcoming of many conventional casement window operating systems is that they are "handed", meaning that a window operating system designed to operate a left-handed window cannot be installed to operate a right-hand window, and vice versa. It would be preferable if a casement window 25 operating system could be provided which is at least largely non-handed and could therefore be installed to operate on either left-handed or right-handed casement windows with minimum reconfiguration and/or component substitution. Many existing and conventional casement window operating systems are also fiddly 30 and difficult to install. This can also make them fiddly and difficult to disassemble and reassemble, for example during repair or maintenance. It is an object of the present invention to provide a casement window operating system which may help to address one or more of the above-mentioned disadvantages, 4 or which may at least provide a useful or commercial alternative to existing casement window operating systems in the marketplace. Further objects of the invention may become evident from the descriptions, explanations and illustrations below. 5 SUMMARY OF THE INVENTION According to a first aspect of the invention there is provided a cranking assembly for a window closure system including: a faceplate; 10 a rotatable handle assembly arranged to pivot relative to the faceplate from a low profile position to an open position for operation by a user. Preferably the rotatable handle assembly presents substantially flush with the faceplate in the closed position. 15 In a preferred embodiment the rotatable handle assembly includes first and second pivoted linkages arranged to flatten with the faceplate in the low profile position and extend out from the faceplate in the open position. 20 Preferably the medial ends of the first and second pivoted linkages terminate fast with an input gear shaft of the cranking assembly. The input gear shaft is preferably coupled to an output shaft via meshed gears. 25 A sash locking assembly may be provided that is responsive to pivoting of said handle assembly for locking a sash with a frame of the window. Preferably the sash locking assembly is coupled to said handle assembly by a linkage including a rack and pinion. Alternatively, a cam and cam follower might be used 30 instead or any other suitable linkage system. In a preferred embodiment the rack slides along the output shaft. Preferably the rack is coupled to a locking bar.

5 In a preferred embodiment pivoting of said handle assembly causes the locking bar to slide into, or out of, locking registration with the sash. 5 The locking bar may have a number of projections that slide into or out of engagement with corresponding formations fast with the sash. Preferably the number of projections comprises a plurality of rollers and the corresponding formations comprise a plurality of ramps disposed along a side of the 10 sash. The linkage may include a link pivotally connected between a rocker and the pinion. The rocker is preferably formed to define an aperture through which the medial ends 15 of the first and second pivoted linkages pass to terminate fast with the input gear shaft of the cranking assembly. Furthermore, the linkages are preferably coupled to the rack and thereby to the locking bar in order that the locking bar is brought from a locking to an unlocking position as the handle assembly is brought from the low profile position to the open position. 20 Preferably the rocker moves the link from a first position, wherein the sash is locked to a second position, wherein the sash is unlocked, in response the first and second pivoted linkages assuming the open position 25 In a preferred embodiment the cranking assembly includes a selectively operable release mechanism for retaining the rotatable handle assembly in the low profile position. Preferably the selectively operable release mechanism includes a catch biased to 30 retain said handle assembly in the low profile position. The selectively operable release mechanism may include a release button coupled to the catch by means of a handle locking bar.

6 A barrel lock assembly may be provided that is arranged to selectively hold the handle locking bar fast thereby preventing disengagement of the catch from the handle assembly. 5 In a preferred embodiment the barrel lock assembly includes a locking plate that selectively abuts the handle locking bar. An elongate sash button may be provided that has first and second ends wherein the first end is disposed to operate the locking plate in response to abutment of the second 10 end with the sash. According to a further aspect of the present invention there is provided a corner gear transmission assembly for a window closure system, including: a housing; 15 first and second gears meshed and normal to each other; first and second sockets mounted in the housing to slide on shafts of the first and second gears and biased toward respective outlet ports of the housing to receive respective axles and couple rotational force therebetween. 20 Preferably the first and second sockets have medial and lateral portions separated by respective flanges biased into abutment against internal rims of the outlet ports. The sockets may be biased by coil springs. 25 In a preferred embodiment, lateral portions of the first and second sockets extend out of the respective outlet ports. The first and second sockets are preferably accommodated in over sized recesses of the housing to facilitate ingress of the lateral portions into the housing. 30 Preferably the first and second sockets have non-circular coaxial bores formed therethrough to receive complementary shaped gear shafts and end portions of said axles for transmission of rotational force therebetween.

7 According to a further aspect of the present invention there is provide an opening assembly for a window, including: a pair of hingedly interconnected arms, each pivotally fastened to a sash and frame of the window respectively with a hinged edge of the window therebetween; 5 a drive unit with an extendible member coupled to one of said interconnected arms by a cam and a cam follower in cooperation. The cam is preferably provided as a slot formed in the one of said interconnected arms. 10 In a preferred embodiment the cam is provided as an S-shaped slot formed in a one of the pair of hingedly interconnected arms pivotally fastened to the frame. The drive unit preferably includes a lead screw to receive input rotational force. 15 The extendible member is preferably coupled to the lead screw by means of a carriage in threaded engagement with the lead screw. Preferably the drive unit includes a slotted stiffening portion that receives the 20 extendible member. According to a further aspect of the present invention there is provided a closure system for a casement window, including: a cranking assembly mounted to a first side of a frame of the window for use 25 by an operator to drive a first axle; a window opening assembly mountable on a second hinged side of the window and driven by a second axle; a corner gear transmission assembly to interconnect the first axle and the second axle. 30 BRIEF DESCRIPTION OF THE DRAWINGS 8 Figure 1 is a view of a casement window according to an embodiment of the present invention in a closed configuration. Figure 2 is a view of the casement window in an open configuration. Figure 3 is a view of a cranking assembly according to an embodiment of the 5 invention in an open or extended configuration. Figure 3A is a view of the cranking assembly in a closed or "low profile" configuration. Figure 4 is a view of the inside of the casement window in an open configuration. Figure 5 is a close up of the cranking assembly from an inner side of the casement 10 window. Figure 6 is a close up of a corner gear transmission of the casement window. Figure 7 is a close up of a linear drive assembly of the casement window. Figure 7A is a close up view of the cranking assembly showing the locking rollers of the locking bar in locking registration with a locking ramp. 15 Figure 7B shows the locking rollers out of locking registration with the locking ramp. Figure 8 is an exploded view of the cranking assembly. Figures 9 to I IC show partially assembled views of the cranking assembly in a closed , i.e. low profile, configuration. Figure 11 D depicts handle assembly linkages of the cranking assembly in the closed 20 configuration. Figure 1 E depicts the handle assembly linkages in an open configuration for cranking of the handle assembly. Figure 11 F is a final partially assembled view of the cranking assembly in the closed configuration. 25 Figures 12 to 12F show partially exploded, and close up views of the cranking assembly in the open configuration. Figure 13 is a view of the exterior of the cranking assembly in the closed configuration. Figure 14 is a close up of the exterior of the cranking assembly in the open 30 configuration. Figure 15 is a view of the corner transmission assembly with top cover removed. Figure 16 is a cross sectional view through the corner transmission assembly showing holes through each socket.

9 Figure 17 is a view of the linear drive assembly with top cover plate and stiffening bracket removed in an open window configuration. Figure 18 is a view of the linear drive assembly with top cover plate and stiffening bracket in place in an open window configuration. 5 Figure 19 is a view of the linear drive assembly in a closed window configuration. DESCRIPTION OF THE INVENTION Referring now to Figure 1, there is depicted a view of a casement window I according 10 to a preferred embodiment of the present invention, in a closed configuration. The same window is shown in an open configuration in Figure 2. The casement window includes a frame 3, for location in a wall opening such as a window, to which a sash 5 is connected by hinges (not visible) along one side. A cranking assembly 7 is mounted to the frame. The cranking assembly functions to unlock and open the 15 casement window. With reference to Figure 3, which shows the cranking assembly in an open, i.e. outwardly extended configuration, the cranking assembly includes a handle assembly 9 for rotation by an operator. The handle assembly is pivotally connected to the 20 remainder of the cranking assembly and may be swung into the cranking assembly to assume a closed configuration as shown in Figure 3A. It will be noted that in the closed configuration the handle assembly presents a flush surface with the faceplate 29 of the cranking assembly that is aesthetically pleasing and of a low profile. 25 Figure 4 is a view of the casement window from the sash side in an open configuration. As seen in overview in Figure 4, the window incorporates a linkage to convey rotational power from the handle assembly 9, via axles I1 and 12, to a linear drive assembly 2. The axles I1 and 12 are interconnected by a corner gear assembly 17 which will be discussed in detail later. The linear drive assembly 2 includes an 30 extendible arm 15. A sash drive arm 21 is pivotally connected to the sash toward the commonly hinged edge of the sash and frame. Similarly, a frame drive arm 19 is pivotally connected to the frame 3 toward the commonly hinged edge of the sash and the frame. The remote ends of the sash drive arm 21 and the frame drive arm 19 are pivotally interconnected. The extendible arm 15 engages the frame drive arm 19 in 10 order to open or close the sash relative to the frame by respectively pulling or pushing on the frame drive arm. Figures 5, 6 and 7 are close up views of the cranking assembly 7, corner gear assembly 17 and linear drive assembly 13, respectively. 5 A sash locking assembly will now be described with reference again to Figure 4 and Figure 5. Spaced along the outside of the sash, opposite the hinged edge, are three locking ramps 22. The locking ramps are formed to releasably engage corresponding locking rollers 26 that extend from sash locking bar 24. The locking rollers run on lugs that are fastened to the locking bar 24 with off-center pins. Consequently the 10 lugs may be twisted for accurate alignment of the locking rollers with the locking ramps. Sash locking bar 24 is slidingly engaged by bar clasps 35 which are fixed to frame 3. As shown in Figure 7A, the sash locking bar 24 supports a coupling roller 30 that is engaged by a slotted plate 37 which extends from the cranking assembly 7. As will be explained, pivoting-out of the handle assembly 9 from the remainder of the 15 cranking assembly 7 causes the slotted plate 37 to move from a first locking position, visible in Figure 7A to a second unlocking position visible in Figure 7B. As the slotted plate 37 slides it forces the coupling roller 30 along so that the locking rollers 26 are brought out of registration with the locking ramps 22. Consequently the sash 5 is no longer retained closed with the frame. 20 Cranking assembly Figure 8 is a somewhat exploded view of the cranking assembly 7 shown with the handle assembly 9 extended. The cranking assembly 7 includes a mounting block 23 which receives opposing left hand and right hand housing plates 25 and 27. The left 25 and right hand housing plates are made with various integrally formed mounting formations to receive and hold a mechanical assembly 3 1. Figure 9 is a view of the mechanical assembly 31 from the left hand side, in a closed configuration, and with left hand housing plate 25 removed. Figure 10 is a view of the mechanical assembly from the opposite side with the right hand housing plate 27 removed. Figures 1 A to 30 11 D are views of the mechanical assembly from the left hand side with various components removed to show the underlying interconnections. Referring now to Figure 1 lA, the mechanical assembly includes a right angled bevelled gear assembly 45 comprising a gear housing 47 which holds first and second I1 meshed bevelled gears 49 and 51. A shaft extends from gear 49 and terminates in a head 53. A output shaft 55 of gear 51 extends forwardly and terminates at its forward end in a socket 56 for receiving axle 11 (Figure 7). A tube 57 slides along output shaft 55 and bears an integrally formed rack 59. Rack 59 meshes with pinion 61. 5 Pinion 61 is integrally formed with step up gear 62 (visible in Figure 10). The step up gear 62 meshes with cover linkage gear 63 (as shown in Figure 10). A link 65 is pivotedly attached between one side of the linkage gear 63 and a rocker 91 (visible in Figure lID). Spring 67 pushes the handle out of the housing when the release catch 89 is activated. The user is then able to grasp the winding handle 77 and pivot the 10 handle to the open position for rotation. The shaft head 53 of the shaft of bevelled gear 49 is pivotally connected to an arm 69. The arm 69 is in turn pivotally connected to forearm 71. Forearm 71 terminates in a handle block 75 to which it is pivotally connected. A winding handle 77 is rotatably 15 attached to the outer end of handle block 75 for use by an operator as will be explained. With reference to Figure I I B, a yoke 95 is pivotally connected at one end to head 53 of the shaft of bevelled gear 49. The yoke is pivotally connected below the pivot connection point of arm 69 to shaft head 53. With reference to Figure IIC, an over-arm 97 is pivotally connected at one end to yoke 95 and at the other end to 20 handle block 75. The over-arm is formed with a longitudinal recess that accommodates forearm 71. The yoke 95 is also pivotally connected to forearm 71 at inter-linkage point 96, which is identified in Figures 1 A, 1 IB, 12A, 12C. It will be noted that handle block 75 and shaft head 53 are interconnected by two 25 linkages, each comprising two pivotally interconnected links. The first linkage is formed of arm 69, and forearm 71. The second linkage is formed of yoke 95 and over-arm 97. The first and second linkages are in turn pivotally connected by a pin through pivot point 96. 30 The medial ends of the linkages terminate on shaft head 53 and handle block 75 at non-coincident pivot points. The length of the linkages, and the location of the pivot points, are selected so that in the closed configuration that is shown in Figure 11 D, the yoke 95, overarm 97 and handle block 75 present a flat outer surface with the angle between the inside of overarm 97 and handle block 75 being 180 degrees. As the 12 handle assembly is swung out to the open configuration, the angle between arm 69 and shaft head 53 increases, and correspondingly, the angle between the overarm 97 and handle block 75 decreases. Finally the angle between the overarm 97 and handle block 75 decreases so that the handle block, and hence winding handle 77, project at 5 approximately right angles from frame 3 thereby providing a convenient winding angle for a user operating handle 77 as shown in Figure I1E. This linkage system can be set up to work with a range of different handle projections and angles With reference to Figure 1 IF, a rocker 91 includes axle protrusions 92 that are 10 pivotally received into corresponding rocker axle pivot holes 94, one of which is visible in Figure 8. As shown in Figures 12E and 12F, the rocker 91 is formed with a hole through which the body of yoke 95 passes for connection to shaft head 53. The pivot axes of the rocker and yoke are coincident in the closed position. The rocker includes a closure surface 98 which presents a tamper proof barrier whilst in the 15 closed configuration shown in Figure I1D. Rocker 91 includes an integrally formed lobe 88 to which is pivotally connected an end of link 65. The crank assembly incorporates a selectively operable release mechanism for retaining the handle assembly in the low profile, i.e. closed, configuration, which will 20 now be described. A sector-shaped release button 79 including first and second sides defining an arcuate periphery therebetween, is pivotally secured at its apex to the left and right hand housing plates 25 and 27 by release button pin 84. Along the first side of the release button 79 an external contact surface 78 is formed for depression by an operator during use. A release button spring 80 is integrally formed with the release 25 button and extends from the second side toward the apex of release button 79. The extended portion of the spring 80 is retained in corresponding mounting formation recesses of the left and right hand housing plates 25 and 27 (visible in Figures 10 and 9 respectively). The extended portion of the release button spring 80 biases the body of the release button away from the spring (i.e. the release button 79 is biased counter 30 clockwise as viewed in the diagram of Figure 11 F). The biasing force of spring 80 is balanced by a finger 81 that is integrally formed with the release button and which extends outward from proximal the junction of the lower side and the arcuate periphery of the release button 79. The range of movement of the finger, and hence the angle of rotation of the release button 79 about pin 84, is limited due to the finger 13 81 being received into opposing rectangular recesses formed into the left and right housing plates 25 and 27. Approximately midway between release button 79 and gear housing 47, there is 5 located a release catch 89. The release catch pivots about an integrally formed pin 93 that is received at either end into recesses formed into the left and right housing plates 25 and 27. The release catch 89 is formed with an integral spring 87 and a body that extends from pin 93 to terminate in a bevelled head 85 having an undercut lip. In the closed configuration shown in Figures 11 A the undercut lip of the bevelled head 85 10 engages a ledge 99 on the underside of over-arm 97 (see Figure 14). As can be seen in Figures 8, 9 and 10, the release catch 89 is received in opposing recesses formed in the left and right housing plates 25 and 27. A release bar 83 is formed with slots at opposing ends. The release bar slots are respectively traversed by 15 the body of catch 89 and the release button finger 81. Consequently the release bar 83 couples release button 79 to release catch 89. With reference to Figure 11 F, a barrel lock assembly 101 is provided, which is shown receiving a complementary key 103. Turning of the key forces a locking plate 105 into abutment with release bar 83 so that the release bar cannot be moved and hence the catch 89 cannot be withdrawn from 20 engagement with over-arm 97. A sash button 107 having a body terminating adjacent locking plate 105 in a bevelled head is provided. As shown in Figures 9 and 10, the body of the sash button extends out of the right and left housing plates 25 and 27. The function of the sash button 107 is to prevent the unit being locked when the sash 5 is away from the frame 3 (ie, the key 103 cannot be turned). When the button is not 25 depressed (ie sash is out) the hook sits in the slot on the lock bar, preventing it from moving. The bevelled edge is to allow the button to return to its normal position if the lock is thrown and the button is released (this will not normally occur) Referring now to Figure 13, assuming that the casement window is closed, an operator 30 (i.e. an occupant of a dwelling in which the window is fitted) will be presented with a closed cranking assembly as shown. Initially the operator rotates key 103 thereby sliding locking plate 105 away from abutment with release bar 83. The operator then depresses the release button external contact surface 78 thereby swinging release button finger 81 away from release catch 89. As the finger 81 is swung away it pulls 14 the release bar 83, which in turn pulls the bevelled head 85 of catch 89 out of engagement with over-arm 97. Due to the outwardly biasing action of spring 67 the rocker 91 pivots outward and thereby swings yoke 95, over-arm 97, handle block 75 and winding handle 77 out also. The operator can then grasp the ejected handle 5 assembly 9 and swing it to its fully opened position as shown in Figure 14. As the handle assembly 9 is brought to its fully opened position, the handle block 75, and with it winding handle 77, is brought to make an angle of 90 degrees with frame 3. As previously explained, this is due to the arrangement of the two handle linkages that was previously discussed with reference to Figures I1D and 11 E. Simultaneously, as 10 rocker 91 is rotated outward it pulls upon link 65 which in turn rotates step up gear 62 of pinion 61. Since pinion 61 is meshed with the rack 59 of tube 57, the tube, and with it the attached slotted plate 37 to which it is attached, are slid outward along output shaft 55. As the slotted plate slides outward it brings with it coupling roller 30. The coupling roller 30 in turn slides sash locking bar 24 so that the locking rollers 26 15 run off locking ramps 22 thereby unlocking the sash from the frame in readiness for the sash to be opened by winding of the handle assembly 9, as will be explained shortly. The operator then grasps winding handle 77 and rotates the handle assembly about 20 input shaft head 53. This action rotates the first bevelled gear 49 which in turn rotates meshed second bevelled gear 51 and hence output shaft 55. Consequently, the axle I I that is coupled to output shaft 55 by socket 56 is rotated. Corner Gear Box Assembly 25 Figure 15 is a plan view of corner gear box assembly 17 with the lid of gear box housing 109 removed to reveal the internal structure. The housing is formed with holes to facilitate fastening to window frame 3. 30 Gear box housing 109 is formed with two orthogonal arms, being input arm 119 and output arm 121 that meet at an apex. Recesses are formed in the gear box housing 109 to receive a bevelled gear housing 123. The gear housing 123 retains meshed right-angled bevelled gears, being input gear 125 and output gear 127 which are coupled to hexagonal input coupling shaft 129 and hexagonal output coupling shaft 15 131 respectively. Shafts 129 and 131 are received into hexagonal coaxial holes formed through cylindrical input and output sockets 111 and 113 respectively. Each cylindrical socket is received into a recess formed toward the end of each of the input and output arms 119 and 121. A portion of each cylindrical socket extends out 5 through a port formed at the outer end of each of the input and output arms 119 and 121. A flange is formed around the circumference of each cylindrical socket to retain the sockets within their respective recesses. Input and output side biasing springs 115 and 117 bias each flange into abutment with the inside rim of each port. The recesses are elongate to accommodate inward movement of the respective sockets I11, 113 10 upon external force being applied sufficient to overcome the biasing force of the respective springs 115 and 117. Input axle 11 and output axle 12 terminate in hexagonal sections that are received into the hexagonal holes of the input and output sockets 111 and 113 respectively. 15 During installation, the gear box end of the input axle 11 is first put into the sprung socket 111. It can then be pushed further into the gear box and its opposite end inserted into socket 56 as shown in Figure 9. An entirely similar operation is undertaken in fitting output axle 12 to socket 113 and thence to lead screw socket 143. 20 Linear Drive Assembly Figure 17 depicts the linear drive assembly 2. The linear drive assembly includes a lead drive unit 13 having a housing 145. A top cover 153 of the housing (visible in Figure 18) has been removed to reveal lead screw 151 which terminates in a lead screw socket 143. The lead screw 151 and lead screw socket 143 are both located in 25 respective intercommunicating recesses formed in housing 145. A screw carriage 135, formed with a thread corresponding to that of lead screw 151, is slidingly fastened to housing 145 to engage lead screw 151. The screw carriage 135 rides along the lead screw 151 as it rotates. Extendible arm 15, which is disposed parallel to lead screw 151, is bolted to the screw carriage 135 at one end and terminates in a 30 cam follower 141. Cam follower 141 is received into an S-slot 139 formed into frame drive arm 19. The frame drive arm 19 is pivotally connected at one end to frame bracket 133 and at its other end to sash drive arm 21. The sash arm is in turn pivotally connected to sash 16 bracket 149 which is in turn fastened to sash 5. With reference to Figure 18, in order to impart rigidity to the assembly a sleeve 137 is provided in which extendible arm 13 rides. The sleeve is fastened between frame bracket 133 and linear drive assembly housing 145. Linear drive assembly cover 153 is also visible in Figure 18. 5 The operation of the linear drive assembly to close the casement window will now be explained with reference to Figures 17A, 18 to 19. Initially, in the full opened position shown in Figure 17A, the sash drive arm 21 and frame drive arm 19 are collinear and in fact they lock out in that position, somewhat like an elbow joint. The 10 distance from cam follower 141 to the frame arm pivot point 142 is indicated by dO. As the operator winds winding handle 77, extendible arm 15 moves rightward and pulls frame drive arm 19 into clockwise rotation (relative to the Figures 17A-19). Consequently the angle p, between the sash drive arm and the frame drive arm, decreases. Simultaneously, the distance between the cam follower 141 and the 15 bottom of the s-slot 139 increases. The overall effect is that the mechanical advantage in the position shown in Figure 18 is somewhat greater in Figure 17A than in the slightly closed position shown Figure 17A. Accordingly, the operator is afforded mechanical advantage at the start of the closing process which may be helpful in overcoming static friction to commence sash closure. 20 Consequently, for a constant rotation of output axle 12, and hence a constant velocity rightward of cam 141, the angular velocity of frame arm 19 as shown in Figure 18 will be at a maximum, although the torque that is applied will be reduced. As a result, the sash 5 closes relatively quickly. As the frame drive arm 19 pivots clockwise 25 (relative to the view provided in Figures 17, 18, 19) the cam follower 141 enters the intermediate portion of S-slot 139. While the cam 141 is in the intermediate portion of the slot the angular velocity of the arm remains relatively high (although slower than at the start) due to the gentle sloping of the slot that is encountered by cam 141. Finally the cam enters the ultimate portion of the s-slot 139. The distance between the 30 cam follower 141 and the pivot point 142 increases to distance d2 during this part of the cam's journey. It follows that as the angular separation between the sash and the frame decreases, the torque applied to frame arm 19 increases while the angular speed of the sash 5 slows. Consequently, the operator, who is supplying the rotational force to axle 12 by rotating the winding handle 77 of handle assembly 9, is provided with a 17 mechanical advantage. This improved mechanical advantage during the last stage of closure of the sash is helpful since it allows the operator to readily turn handle assembly 9 in order to bring the sash into sealing closure with the frame 3. 5 It will be realised that the preferred embodiment of the invention which has been described is exemplary only. Those skilled in the art will realise that other embodiments and variations are possible and may be implemented within the scope of the appended claims.

18 Parts List 2 linear drive assembly 80 release button spring 3 Frame 81 release button finger 5 Sash 83 release bar 7 cranking assembly 84 release button pin 9 handle assembly 85 release catch bevelled head 11 input axle 87 release catch spring 12 output axle 88 rocker lobe 13 lead drive unit 89 release catch 15 extendible arm 91 rocker 17 corner gear assembly 92 rocker axle protrusions 19 frame drive arm 93 release button pin 21 sash drive arm 94 rocker axle pivot holes 22 locking ramps 95 yoke 23 mounting block 96 inter-linkage point 24 sash locking bar 97 over-arm 25 left hand housing plate 98 rocker closure surface 26 locking rollers 99 over-arm ledge 27 right hand housing plate 101 Barrell lock assembly 29 faceplate 103 key 30 coupling roller 105 locking plate 31 mechanical assembly 107 sash button 35 bar clasps 109 gear box housing 37 slotted plate 111 input socket 45 right-angled bevelled gear assembly 113 output socket 47 gear housing 115 input side socket biasing spring 49 first bevelled gear 117 output side socket biasing spring 51 second bevelled gear 119 input arm 53 shaft head 121 output arm 55 output shaft 123 bevelled gear housing 56 socket 125 gear box input gear 57 tube 127 gear box output gear 59 rack 129 input coupling shaft 61 pinion 131 output coupling shaft 62 step up gear 133 frame bracket 63 cover linkage gear 135 screw carriage 65 link 137 sleeve 67 spring 139 S-slot 69 arm 141 cam follower 71 forearm 143 lead screw socket 75 handle block 145 linear drive assembly housing 77 winding handle 149 sash bracket 78 release button external contact surface 151 lead screw 79 release button 153 linear drive assembly top cover 5

Claims

1. A cranking assembly for a window closure system including: a faceplate; 5 a rotatable handle assembly arranged to pivot relative to the faceplate from a low profile position to an open position for operation by a user.

2. A cranking assembly according to claim 1, wherein the rotatable handle assembly presents substantially flush with the faceplate in the closed position. 10

3. A cranking assembly according to claim I or claim 2, wherein the rotatable handle assembly includes first and second pivoted linkages arranged to flatten with the faceplate in the low profile position and extend out from the faceplate in the open position. 15

4. A cranking assembly according to claim 3, wherein medial ends of the first and second pivoted linkages terminate fast with an input gear shaft of the cranking assembly. 20

5. A cranking assembly according to claim 4, wherein the input gear shaft is coupled to an output shaft via meshed gears.

6. A cranking assembly according to any one of the preceding claims including a sash locking assembly responsive to pivoting of said handle assembly for locking a 25 sash with a frame of the window.

7. A cranking assembly according to claim 6, wherein sash locking assembly is coupled to said handle assembly by a linkage including a rack and pinion. 30

8. A cranking assembly according to claim 6, wherein the sash locking assembly is coupled to said handle assembly by a cam and cam follower.

9. A cranking assembly according to claim 7 when dependent on claim 5, wherein the rack slides along the output shaft. 20

10. A cranking assembly according to claim 9, wherein the rack is coupled to a locking bar. 5

11. A cranking assembly according to claim 10, wherein pivoting of said handle assembly causes the sash locking bar to slide into, or out of, locking registration with the sash.

12. A cranking assembly according to claim 11, wherein the sash locking bar has a 10 number of projections that slide into or out of engagement with corresponding formations fast with the sash.

13. A cranking assembly according to claim 12, wherein the number of projections comprises a plurality of rollers and the corresponding formations comprise 15 a plurality of ramps disposed along a side of the sash.

14. A cranking assembly according to claim 8, wherein the linkage includes a link pivotally connected between a rocker and the pinion. 20

15. A cranking assembly according to claim 14, wherein the rocker defines an aperture through which the medial ends of the first and second pivoted linkages pass to terminate fast with the input gear shaft of the cranking assembly.

16. A cranking assembly according to claim 14, or claim 15, wherein the linkages 25 are preferably coupled to the rack and thereby to the locking bar in order that the locking bar is brought from a locking to an unlocking position as the handle assembly is brought from the low profile position to the open position.

17. A cranking assembly according to any one of the preceding claims, including a 30 selectively operable release mechanism for retaining the rotatable handle assembly in the low profile position. 21

18. A cranking assembly according to claim 15, wherein the selectively operable release mechanism includes a catch biased to retain said handle assembly in the low profile position. 5

19. A cranking assembly according to claim 18, wherein the selectively operable release mechanism includes a release button coupled to the catch by means of a handle locking bar.

20. A cranking assembly according to claim 19, including a barrel lock assembly 10 arranged to selectively hold the handle locking bar fast thereby preventing disengagement of the catch from the handle assembly.

21. A cranking assembly according to claim 20, wherein the barrel lock assembly includes a locking plate that selectively abuts the handle locking bar. 15

22. A cranking assembly according to claim 21, including an elongate sash button having first and second ends wherein the first end is disposed to operate the locking plate in response to abutment of the second end with the sash. 20

23. A corner gear transmission assembly for a window closure system, including: a housing; first and second gears meshed and normal to each other; first and second sockets mounted in the housing to slide on shafts of the first and second gears and biased toward respective outlet ports of the housing to receive 25 respective axles and couple rotational force therebetween.

24. A corner gear transmission assembly according to claim 23, wherein the first and second sockets have medial and lateral portions separated by respective flanges biased into abutment against internal rims of the outlet ports. 30

25. A corner gear transmission assembly according to claim 23 or claim 24, wherein the sockets are biased by coil springs. 22

26. A corner gear transmission assembly according to any one of claims 23 to 25, wherein lateral portions of the first and second sockets extend out of the respective outlet ports. 5

27. A corner gear transmission assembly according to any one of claims 23 to 25, wherein the first and second sockets are accommodated in over sized recesses of the housing to facilitate ingress of the lateral portions into the housing.

28. A corner gear transmission assembly according to any one of claims 23 to 27, 10 wherein the first and sockets have non-circular coaxial bores formed therethrough to receive complementary shaped gear shafts and end portions of said axles for transmission of rotational force therebetween.

29. An opening assembly for a window, including: 15 a pair of hingedly interconnected arms, each pivotally fastened to a sash and frame of the window respectively with a hinged edge of the window therebetween; a drive unit with an extendible member coupled to one of said interconnected arms by a cam and a cam follower in cooperation. 20

30. An opening assembly according to claim 29, wherein the cam is provided as a slot formed in the one of said interconnected arms.

31. An opening assembly according to claim 30, wherein the cam is provided as an S-shaped slot formed in a one of the pair of hingedly interconnected arms pivotally 25 fastened to the frame.

32. An opening assembly according to any one of claims 29 to 31, wherein the drive unit includes a lead screw to receive input rotational force. 30

33. An opening assembly according to claim 32, wherein the extendible member is coupled to the lead screw by means of a carriage in threaded engagement with the lead screw. 23

34. An opening assembly according to claim 33, wherein the drive unit includes a slotted stiffening portion that receives the extendible member.

35. A closure system for a casement window, including: 5 a cranking assembly mounted to a first side of a frame of the window for use by an operator to drive a first axle; a window opening assembly mountable on a second hinged side of the window and driven by a second axle; a corner gear transmission assembly to interconnect the first axle and the 10 second axle.

36. A closure system for a casement window according to claim 35, wherein the cranking assembly is according to any one of claims 1 to 22. 15

37. A closure system for a casement window according to claim 35, wherein the window opening assembly is according to any one of claims 29 to 34.

38. A closure system for a casement window according to claim 35, wherein the corner gear transmission assembly is according to any one of claims 23 to 28. 20

39. A casement window including a closure system according to any one of claims 35 to 38.