AU2016100113A4 - Heavy duty drive for chainwinder - Google Patents

Abstract

The invention relates to a chainwinder comprising a housing formed by a body and a metal base, to receive a chain therein; a drive mechanism engageable with the chain, to selectively drive the chain from the housing to alter the degree of openness of an attached window, the drive mechanism including at least one drive gear rotatable about an axis extending between respective ends of the drive gear, the drive gear being mounted relative to the body at a first end portion and mounted relative to the base plate at a second end portion; and a wear component mounted between the base and the second end portion of the drive gear. The invention is particularly suitable for heavy duty chainwinders, and reduces the wear on the drive gear relative to conventional chainwinder designs, enabling a longer functional life. ~rW r'~oZIA ~"X\ AW" SOO~ ' ANg & A'.' " 14' ~a N \' \ NM ~r' N41 mmm d\N .. . . .. .. . . .. .. . .. . .. . . .. .. .. . . . . .. . .. . .. .. .. .. .

Description

I HEAVY DUTY DRIVE FOR CHIMNWIINDER Field of the Invention [0001 The present invention relates to an improved chainwinder It has particular application to a chainwinder having a heavy duty drive, although it could be used and provide advantages in ehainwinders that are not "heavy duty". For context, the term "heavy duty" is used here to general refer to chainwinders that can withstand over 20 kilogram torque and preferably over 50 kilogram torque. [00023 This invention relates to a chainwinder and in particular to an improved chainwinder for a windowv Whilst the invention may be applied to opening or closing a range of articles including skylights etc, for convenience sake it shall be described herein in terms of a chainwinder for opening and closing windows. Incorporation by Reference [00033 This application claims priority from Australian provisional application no 2015900339, the entire content of which is hereby incorporated by reference. Background of the Invention [00043 A window winder of the present type, generally uses a chain connected to a hinged windows such that varying the length of the chain varies the degree of openness of the window. The invention is particularly relevant to lockable window wonders but is not limited to such [0005] Generally, such mechanisms are used on windows, which are pivotally hinged at a top portion with the window winder being attached to the windowsill and a chain extending from and attached to a bottom portion of the window so that it is able to pivot outwards around the top hinge. [0006] A drive in a chainwinder receives positive and negative forces. In the positive force the chainwinder is providing a push force to open the widow In the negative the chainwinder is provider a pull force to close the window. However the requirements for opening and losing of windows has substantially increased over the past decade. This includes the following: (a) Heavier windows = double or triple glazing; 2 (b) Keyed operation; (C) Keyless push closed; (d) Higher security (e) Hilgher safety for second storey window (f) Increased child safety. [0007] The structure of chainwinders has not been sufficient to meet these new requirements, The structure of the chainwinder in both positive and negative force directions needs to be improved. [0008] A particular important feature of lockable window winders is the security offered by such products Windows are a clear entry point to premises and therefore like doors require locks to prevent unauthorised access. However unlike doors, windows generally need to be left partially open to allow fresh air to enter. Further due to the window not being the usual access when people leave preinses the doors are locked but the windows are overlooked, Itlis therefore important to provide lockable chainwinders that maintain security. [0009] There is already a substantial security element of lockable chainwinders in that It requires the key to lock in closed position or in partially open position which still prevents access, while still allowing manual closing of the window. [0010] However a first particular security problem associated with window winders of this kind is that often the drive handle is forced. This can cause gears to be forced due to material failure or misalignment or disconnection. [0011] Another security problem cooperation ofchainwinders is that the drive gear needs to have components of different precision and qualiy and strength. Unfortunately it can be usual practice for the lowest quality and lowest strength to be used and allows one or more sections of the drive gear to fail over continuous use or when undue force is applied. This makes a security issue in that the window could be readily opened. However only increasing strength components does not necessarily stop al problems and particularly forced nisalignment of one of the many interconnecting parts in a chainwinder, [0012] A further particular problem is that as windows are getting heavier by being double or triple glazed, or by the use of materials which will resist deformation or be more weather resistant, it will experience greater loads during operation, which puts greater stress on the component parts. One subsequent problem is that the components will wear more quickly under these higher loads, resulting in rough operation of the chainwinder or breakage/failure of component Parts. [0013] A constraint in addressing this problem is that, from a commercial perspective, it is advantageous if the structure of the chainwinder fits the mounting location on the window sill for installation, having standard dimension. Otherwise, alteration of the chainwinder wvil result in the industry needing to alter window frames to fit new chainwinders and altering windows to fit into new window frames and altering flysereens to fit within the new frames over the new chainwinders. [0014] Accordingly, the present invention seeks to provide an improved chainwinder xvhich will overcome or substantialy ameliorate at least one or more of the deficiencies of the prior art, or to at least provide an alternative. [0015] It is to be understood that if any prior art information is referred to herein, such reference does not constitute an admission that the information forms part of the common general knowledge in the art, in Australia or any other country. Summary of the Invention [0016] According to a first aspect of the present invention, there is provided chainwinder comprising: a housing formed by a body and a metal base, to house a chain; a drive mechanism engageable with the chain, to selectively drive the chain from the housing to alter the degree of openness of an attached window, the drive mechanism including at least one drive gearotatable about an axis extending between respecdve ends of the drive gear. the drive gear being mounted relative to the body at a first end portion and mounted relative to the base at a second end; and 4 a wear component mounted between the base and the rst end portion of the drive gear [0017] The wear component functions to reduce the wear experienced on the at least one drive gear. In known Chainwinders, an end portion of the at least one drive gear is mounted directly in an aperture in the base plate Because the base is typically made of steel, and the drive gear is typically tonned of zinc or a zinc alloy, this can resul in problems with the drive gear wearing over time, as the chainwinder is used. This problem is exacerbated in heavy duty chainwinders This wear means that the chainwinder operates less smoothly, and in some cases may lead to mechanical failure or breakage, or misalignment of parts. Accordingly, the wear component of the present invention functions to prolong the national life of the chainwinderby reducing wear on the drive gear. [00181 The wear component may be formed of a softer material than the metal base. If the base plate is formed of steel, for example, the wear component may be formed of brass, bronze, zinc, Nylon or another polymer. This reduces the wear on The at least one drive gear, relative to having the drive gear engage directly with the base. [0019] Instead, or in addition to forming the wear component of a softer material the wear component may engage the second end portion of the drive gear along a bearing surface that extendslongitudinally along the axis, and the length of the bearing surface nay be greater than the thickness of the base. This means that, relative to conventional chainwinders, there is greater bearing surface area with the end portion of the drive gear. [0020] The wear component may comprise a bush non-rotatably mounted to the base and extending into a hole in the base, the bush having a cylindrical hole therethrough, and wherein the second end portion of the drive gear is received within the cylindrical hole. [0021] The at least one drive gear may comprise a sprocket gear, having a plurality of teeth to directly engage the chain, with the axis of rotation substantially perpendicular to the base. [0022] According to a further aspect of the invention, there is provided a chainwinder having a heavy duty drive, the chainwinder including a housing formed by a covering body and closed by an attachable closing base, the housing for receiving a chain then; wherein the heavy duty drive includes: a drive means, engageable with the chain, having at least one drive gear to selectively drive the chain from the housing and alter the degree of openness of an attached 5 window; the at least one drive gear including at least one drive element rotatably mounted on at least one axis; and axis retention mechanisms associated with the housing for mounting of the ends of the at least one drive gear. [0023] Preferably the axis retention mechanisms include fixed supports connecting the housing in a fixed manner and which mount the ends of the at least one drive gear in a rotatable manner. 0024] The heavy duty drive can have the at least one drive gear includes a plurality of separate drive elements formed to their individual strength and accuracy and which are rotatably mounted on at least one axis and interfit to rotate fixedly relative to each other. [0025] In one particularly beneficial fomA the chainwinder has a heavy duty drive with the drive mechanism of the chainwinder including first and second drive elements on two axes. the drive elements on one axis is a worm gear, and drives the drive elements on a second axis including a sprocket gear engaging with the worm gear and further including on the second axis a sprocket driven by the sprocket gear and having teeth for interengaging the lirks of the chain. However, different variations may also be possible, including a three-axis worm gear [0026] The axis retention mechanisms can include fixed supports for each of the firs t and second drive elements connecting to the housing in a fixed manner and which mount the ends of the respective drive in a rotatable manner. [0027] Preferably the axis retention mechanisms includes an extremity of drive element includes a surface orthogonal to the at least one axis that in position engages an inner surface of the chainwinder housing or closing base. [0028] Preferably the axis retention mechanisms includes an extremity of drive element includes an end to the at least one axis that in position engages a receiving inner surface of the chainwinder housing or closing base. [0029] Preferably the axis retention mechanisms includes an extremity of drive element includes a bush orthogonal to the at least one axis that in position engages an inner surface of the chainwinder housing or closing base. [0030] Preferably the axis retention mechanisms includes flat surfaces for the worm gear. [003] Preferably the axis retention mechanisms includes a bearing in. base.

6 [00323 Preferably the axis retention mechanisms includes a spring washer and a bearing surface [0033] Preferably the axis retention mechanisms includes a bush and wafer washer spring to mount the drive gear in the form of a worm gear and reduce wear on the housing. [0034] Preferably the axis retention mechanisms includes a drive means of the handle in the form of support of the worm gear at both ends in a substantially parole flat surfaces such as by the bush and wafer washer spring at one end and the housing at the other end. [00353 Preferably the drive gear includes drive elements on at east two axes. [0036] The drive gear of the chanwinder can include drive elements on only two axes. [0037] Ihe drive elements of the chainwinder on one axis can include a worm gear. [0038] The drive elements on a second axis can include a sprocket having teeth for interengaging the links of the chain and a sprocket gear engaging with the wnrm gear [0039] Preferably the drive elements on the one axis and the drive elements on the second axis are located so the two axes are substantially adjacent but in orthogona planes to each other to effect the wonI gear drive of the sprocket gear to drive the sprocket driving the chain. [00403 Also the invention provides a heavy duty drive for a chainwinder that can be retrofitted or initially included in a range of chaimwindersr [0041] Other aspects of the invention are also disclosed. Brief Description of the Drawings [0042] Notwithstanding any other foms xhich may fall within the scope of the present invention, preferred embodiments of the invention will now be described, by way of example only, with reference to the accompanying drawings in which: [0043] Figures lA, 1B and 1C show an above view and two underneath views without closing base respectively, showing a general structure of a chainwinder able to be used in the present invention; [0044] Figure 2 is a diagrammatic view of a two-axis drive structure for use in the present 7 invention; [0045] Figures 3A, 3B and 3C show photographic views of component parts of sprocket means for use in a first embodiment of the invention. showing sprocket with drive gear, supporting spindle, and housing; [0046] Figures 4A, 4B, 4C and 4D show photographic view of assembled sprocket means for use in a second embodiment of the invention showing assembly of sprocket with drive gear, supporting spindle, and housing; [0047] Figures 5A, SB, 5C 5D and 5E show photographic viesv of component parts of handle drive means for use in the first embodient of the invention, showing handle mount with worm gear nount and ratchet wheel, and separate worm gear, and bushes and housing; and [0048] Figures 6A, 6B and 6C shows photographic view of assembled handle drive means for use inist embodiment of the invention embodiment of Figure 2, showing assembly of handle mount with worm gear mount and ratchet wheel, and separate worm gear, and bushes and housing of Figures 5A, 5B, 5C, 5D and SE. Description of Preferred Embodiments [0049] It should be noted in the following description that like or the same reference numerals in different embodiments denote the same or similar features. [0050] Referring to the drawings there is shown the general view in Figures 1 TA, B and IC of a chainwinder 12 including a housing forrned by a covering body 14 and an attachable base 20, formed ofmetal (typically steel) and provided as a closing base plate. The housing is for receiving a chain 41 therein and a drive means is engageable with the chain The housing 14 as an extended elongated upper body 15 of one height with a raised portion 16 of a greater height. 1his raised portion 16 holds a working area of the drive means within the housing. The housing 14 of the chainwinder 12 allows for a folded planar pathway for allowing a chain 41 to extend and protrude out a side opening of the housing [0051] A handle 18 extends from the raised portion 16 for driving the drive means. The drive mechanism is to selectively drive the chain 41 from the housing and alter the degree of openness of an attached window. A keylock 19 is also located in the raised portion 16 and forms part of S the lock means to prevent further driving of the chain 41 from the housing and thereby prevent further opening ofthe attached window. 0052] As shown in Figure 2 there is a drive mechanism comprising of the worm gear 51 which is mounted on spindle 50 and driven by the handle 18, and sprocket gear 62. The drive mechanism has drive elements on two axes [0053] On a first axis (Axis 1) there is a spindle 50 that has a worm gear 51 near one end 53 and a ratchet gear 45 near the other end 52 which engages the handle 18. [0054] On the second axis is a sprocket gear 62 which drives a coaxial sprocket 65 which drives the chain 41. The turning of the handle 18 thereby drives the worm gear 51 located along the first axis (Axis ) and is positioned relative to the second axis (Axis 2) so that the worm gear engages the sprocket gear 62 to allow driving of the sprocket gear 62 by the worm gear 51. [0055] The chainwinder can include an idler gear, in a versatile variation or embodiment of the invention, having a plurality of peripheral teeth that fit into the chain at the distal end of the chain from the end that extends out of the chain winder housing. [0056] The idler gear provides a turning arc for the chain which is following an arcuate path within the chain winder housing: wherein the idler gear having a central formation, in the form of a shoulder, to limit deflection or torsional deformation of the idler gear or deformation by the contact of the sprocket idler gear to the rest of the chainwinder such as bulging of chain within casing. when the drive gear is forcibly overdriven, [0057] In a preferred embodiment, the invention provides a chainwinder 11 including a housing 14 with closing base 20 for securing to a window ledge. A chain 41 extendssout of the housing 14 through opening in the side of the housing and allowing chain 41 to be attachable to an openable window by attachment bracket 41 at the end of the chain 41, A drive means including a sprocket gear 62 and sprocket 65 and a worm gear 5 1 are driven by a rotatable handle 18 extending external of the housing 14 allowing the user to vary the length of the chain 41 extending out of the housing in order to vary the degree of the opening of the window [0058] The chainwinder includes a locking means 61 including a lock slide associated with the drive means of the chain and preventing the chain from being further extended from the housing, wherein the locking means includes a key lock for effecting movement of the lock slide 9 between a lockable and an unlockable position and the ratchet gear 45 or sprocket gear 62 is coaxial and adjacent the rotatable handle 18, [0059] In order for the various details of the invention to be shown portions of the chainwinder 12 of Igure 1 are shown in more detail in other drawings [0060] In particular with reference to Figure 2 there is a diagrammatic view of the two-axis drive means. There is shown a drive mechanism which is provided in the form of a drive means having a worm gear 51 connetable to a ratchet gear 62 and connectable to handle 18 to drive the drive means. In turn, these engage sprocket gear 62 to drive sprocket 65. Teeth of sprocket 65 engage with the chain to selectively drive the chain in or out of the housing, to open or close an attached window. This is identified as a two-axis drive means as the handle 18, worm gear and ratchet gear 45 rotate around one axist while the sprocket gear 62 rotates about a second axis, [0061 One option to improve strength would be to "bulk up" the chainwinder but this would raise difficulties in mounting the chainwinder at the mounting location on existing window sils, and to meet the stuctural requirements of present windows and flyscreen structures for windows that ft over the chainwinders and cover the windows within the window frames. The industry has a need for chainwinders to ft within the confines of the housing of the current chainwinder. Alteration of the dimensions of the chainwinder would will result in the industry needing to aher window frames to fit new chainwinders and altering windows to fit into new window frames and altering flyscreens to fit within the new frames over the new chainwinders. This approach is not a commercial viability and therefore the solution to the problem of improving perfonnance while remaining within the constraints of the industry renders this a difficult problem to resolve. [0062] It has been determined by the applicant that the strength and durability of a chainwinder can be improved by any one of the following, or a combination of these elements: (a) For one or more of the following parts of the chainwinder: (i)The handle which is used to drive the drive means; (ii) The drive means vhich is used to drive the sprocket gear; 10 (ii) The sprocket gear which engages and drives the chain to extend in or out of the housing to move the connected window; (b) Undertake one or more structural variations: i)Provide a stabilisizing moutin to prevent or minimize deviant movement other than intended movement, in this way to eliminate slight deviation which would have caused the next connected element to receive unwanted deviated forces and thereby avoid amplifications of such deviated forces that can result in: (A) misaignment of gearing providing slipping of drive to thev indowv to allow forced opening of the window; (B) jumping of gearing to forcibly rattle window open (C) breaking of the drive element which results in complete failure of the window closure; (D) misalignment of components so the designed mounting is not at performance position but at an unexpected angle which then results in defornation components of the housing by forceswavy less than 50 kilogram torque or other element failure due to misalignment of elements producing in breakage of window closure; (ii) Provide parts from more than one constituent to allow individual subparts to be formed of required accuracy and required strength rather than an average accuracy and average strength if formed as single element; (iii) Integrate the mounting structures into housing while still alloxving for rotation of gearig. (iv) Provide drive elements on two fixed axes to engage other and mount the ends of the drive elements rotatably on fixed mounts associated with the housing to reduce rotation wear and to retain the two axes at substantially immnovable relative positions.

I l (C) improvements in elements including interengagement of elements include: (i)flat surfaces for worm gear, (i) a bush or other wear component in housing base, for mounting an end portion of a drive gear, (iii)| spring washer and bearing surface, (iv) a bush and xafer washer spring to mount the drive gear in the form of a worm gear and reduce wear on the housing; (v)a drive means of the handle in the form of support of the worm gear at both ends in a substantially parallel fiat surfaces such as by the bush and wafer washer spring at one end and the housing at the other end. [0063] Referring to figures 3A, 3B and 3C there is shown the mounting of the sprocket 65 on a cylindrical shaft 63 which further holds a sprocket gear 62 that engages vith a worm gear 51 which can be drien by the handle 18 extending out of the housing [0064] In this arrangement there is a fixed spindle 63 which extends between axis retention mechanisms associated with the top 16 of the housing and the closing base 20 of the housing for mounting of the ends of the at least one drive gear The axis retention mechanisms include fixed supports connecting to the housing in a fixed manner arid which mount the ends ofhe fixed spindle upon 63 which are mounted the drive gear in a rotatable manner. [0065] The mounting of the spindle 63 to the base of the housing 20 is by end 632 protruding into hole 25 in base 20 Preferablythe hole is structured such as in triads to readily hold the end of spindle ila non-rotational fitting [0066] The spindle includes a collar 633 spaced from the end and fixed to the spindle so the drive elements can readily rotate on the spindle. This helps position the sprocket 65 relative to the base 20, and avoids direct abrasive wear between the sprocket 65 and base 20 during operation of the chainwinder. [0067] The other end or top end 634 of the spindle 63 is mounted to the top 16 of the housing leaving space for the sprocket gear 62 to readily rotate on the spindle when driven by the worm 12 gear 51. The spindle gear being mounted on. the same axis as the sprocket drives the sprocket 65 which engages and drives the chain of the chainwinder, [0068] A substantial hnprovement is provided by supporting the shaft 63 at a top and bottom connections so as to reduce any movement out of axis of the rnounting of the sprocket 65 and sprocket gear 62 which therefore reduces any offsetting of inter-engageiment of parts which could result in slipping of such engagement allowing forcing of the chain winder mechanism. This is particularly not wanted when windows attached to such chain winders form a part of the security of the building having the windows. [0069] This improvement of mounting of the shaft 63 is provided by the shaft having cylindrical portion 631 with a diameter of one constant size to be received into mounting through-holes in the sprocket 65 and sprocket gear 62. Shaft 63 further includes a second cylindrical portion 633 of greater dimension that the first portion 631 and is close but spaced from the lower end ofthe shaft 632, As shown, particularly in figure 3B without any sprocket 65 and sprocket gear 62 being in position, the top of the shaft 63 is mounted into a top receiving blind hole of the raised portion 16 of the housing at the bottom of the shaft 632 is received into a mounting hole 25 in the attachable closing base 20, The second cylindrical portion 633 is thereby located substantially adjacent the top surface of the attachable closing base 20 and further assists in preventing off axis movement of the shaft 63. [0070) Thereby in position as shown in Figure 3C the sprocket 65 and sprocket gear 62 are maintained to be able to rotate around the shaft 63 in a substantially immovable axial position. in addition the spindle 50 provides a bearing surface that extends longitudinally along the axis of rotation of the sprocket gear 62. The bearing surface area, between the non-rotatable component is much greater than in conventional chainwinders, where the sprocket gear 62 engages directly in hole 25 of the metal base 20. This increased bearing surface area results in reduced wear on the parts, and in particular on the end portion of the sprocket gear 62. In tun, this extends the useful life of the chainwinder. The spindle 50 may be formed of zinc or zinc alJoy, or other materials that provide sufficient mechanical strength to cope with the forces on the chainwinder. [0071] Figures 4A, 4B, 4C and 4D, depict a different embodiment of the invention. Figure 4D shows a metal base 20 having a mounting hole 25 punched in it. As shown in figures 4B and 4C, a wear component, in the firm of bush 653, is attached to the base 20 and receives the shaft 63 13 as shown in Figure 4A, The bush 653 has a collar portion which locates on the top (ie internal) surface of the base 20, and an extension that locates within hole 25. [0072] In this embodiment the drive gear is not mounted on a non-rotatable spindle extending therethrough. Instead, this form of sprocket gear 62 has an integral protruding shaft 63 that provides an axis of rotation for the sprocket gear 621 At one end (the top, when the chainwinder is installed) the shaft 63 is mounted relative to the inside surface of the housing, At the other end (the bottom, when the chainwinder is installed), the shaft 63 is able to mount rotatably in bush 653, which is mounted to the base 20. Again, the shaft can extend though the base 20 and be held in position to fix the axis of rotation. It can be seen that the bush 653 spaces the rotatable elements from the base 20, which will avoid direct wear between the sprocket 65 and base 20, [0073] in addition, however, the bush reduces the wear on the end of the protruding shaft 63 of sprocket gear 62. As seen in Figure 4D, the bush 653 has an extended portion that locates in hole 25, as shown in Figure 41), so as to line the circumference of the hole. In conventional chainwinders without bush 653, the end of the shaft would engage directly with the edges of the hole 25. Since the base plate 20 is generally formed of steel, and the sprocket gear 62 is formed of zinc or a zine alloy, engagement between the end of shaft 63 and the edges of hole|25 can result in significant abrasive wear on the shaft 63 over time. This is exacerbated in heavy duty chainwinders vhich are required to resist higher loads. Furthermore, the act of punching the hole 25 tends to result in the hole 25 having a thin edge, which also exacerbates the wear on shaft 63 because it reduces the bearing surface between the end of shaft 63 and edge of hole 25. [0074] There are at least two reasons explaining why the wear between the bush 653 and the end of shaft 63 can be significantly less than in conventional wonders, where wear is caused by engagement of shaft 63 with the edges of hole 25. First, the bush 653 provides a greater surface area for engagement with the end of shaft 63. Second, the bush 653 can be formed of a softer material than steel base 20. For example, bush 653 is preferably formed of Nylon, but could also be formed of another polymer, or could be forced of brass, bronze or zinc(depending on the material of sprocket gear 62). [0075] Referring to Figures SA and 5B there is shown a drive means which is provided in the form of the handle 18 which has a spindle 63 which extends through the opening of the raised section 16 of the housing 14. The spindle 63 further supports the worm gear 52 and the ratchet gear 62 by extending therethrough. In this form a drive means is provided in the form of the handle 18 which has a spindle 63 and extends through the opening of the housing 14 and further supports the worm gear 5i and ratchet gear 62. [0076] In particular in Figure 5A there is the use of a drive element formed of separate interengaging parts In this way the parts can be made with the required strength of material and the required accuracy for its particular application but can be mounted together to drive each other in a defined combined manner, In this drive gear there is a worm gear 51 on one axis which engages and drives the sprocket gear and sprocket on another axis that drives the chain. This worm gear 51 has a female shaped receiving axial formation on an inner side of the external worm gear. A male complementary shaped axial formation is at a distal end to a handle drive means 52 that connects to the handle 18 Between the male complementary shaped axial brmnation and the handle drive means 52 is a fine toothed ratchet gear that engages with a locking means in order to allow the window to be pushed closed in one direction when locked but not to be pulled open in the other direction Therefore it can be seen that the teeth of the ratchet gear need to have high strength and small steps and therefore are beneficially made of harder material and to a higher strength than other components of the drive means. To combine these two drive elements the male complenentary shaped axial fonnation is fitted into the complementary shaped female axial formation with the nylon gear 522 and washer 521 therebetween to reduce rotational wear. A mounted form of this gear in the housing is shown in Figure 5D. [0077] In Figure 5B there is used a brass spring washer 523 and a bearing 521 having a bearing surface for engaging the drive element. [0078] As shown in the exploded views of Figures 6A. 6B and 6 there is provided a drive nians having a won gear 51 connectable to a ratchet gear 45 and connectable to handle 18 to drive the drive means. [0079] The worm gear 51 includes an outer helical thread 52 of substantial depth and strength and lowering a number of rotations per centimetre so as to fonI a high strength height torque worm gear 51 to engage the sprocket gear 62 and drive the chain 41. To aid this strength and reduce any slipping or movement out of axis the worm gear 51 includes a supporting protruding and axially aligned cylindrical fot 53 and at the other end also axially aligned in the receiving shaped blind hole 54. By allowing the outer helical thread 52 to have a reasonably large diameter further increase torque, the blind hole 54 although having a smaller diameter is still 15 suficient to provide a nmltifAceted shaped blind hole 54 providing large fictional driving surfaces. [0080] The ratchet gear 45 has a planar disc with sawtooth edgings to provide the one-way ratchet mechanism and isn mounted on an axis which on one side has a driving leg 64 with a circumferential multifaceted shaped surface that is complementary and receivable within the nmtifaceted shaped blind hole 54 of the worm gear 51. Also on the axis but on the other side of the planar disc 62 with sawtooth edgings is a head section 68 able to connect and be driven by an extemal handle 18, [0081] A bush 522 and wafer washer spring or thrust washer 46 mount the drive gear including the worm gear 51 and ratchet gear 45 at one end while at the other end is provided a flat surface 26. When mounted within the housing 14 as shown in figure 6B the drive gear aligns with the opening in the raised section 16 of the housing 14 and is mounted to have flat surfaces at either end provided by the bush and wafer washer spring and the inner surface of the housing 14 at one end and the supporting flat surface 26 at the other end In this way there is provided a stable nmounting of the won gear while minimizing wear on the housing. [0082] It can be seen that the improved drive means mounting is provided by separate elements formed initially and being interfited so as to form a cooperating unit'his is shown particularly in figures 6A, 6B and 6C. A particular benefit provided by this approach is that separate components can be formed with higher accuracy or higher or lower strength or for allowing ready adaption of different models or for after sales repairs. For example the ratchet gear 62 includes a sawtooth edging which must have a plurality of stopping points to allow the mechanism to be locked in particular degree of openness of the window while the sawtooth edging has to be further of sufficient strength to be able to not be damaged or give way when the reverse force is applied. [0083] It can be seen that the worm gear 51 has a solid worm external structure while the ratchet gear 45 has a plurality of tine circumferential teeth. The separate structure allows for maximum strength and precision matching of manufacture dependent on the part. In particular the teeth of the ratchet can be finely made and even with different stronger material so as to avoid chipping or shearing when the drive gear is forced, [0084] Mounting between the parts is further strengthened by the ratchet gear 45 having 16 central mounting shape that matches central mounting opening in the worm gear. [0085] An important element of the drive means shown in figures 5A to and 5E is the further support to ensure the rotation of the worm gear 51 is readily possible by the connection 68 to the handle 18 other such rotation is retained around a common axis. [0086] This is achieved by adding the assembled drive means abutting an upper washer that is retained in an orthogonal direction to the common axis by engaging support of undersurface of the housing 14 of the chainwinder The lower foot 53 of the vorm gear 51 is retained in a metal bush 523 mounted to an inner support held by the inner surface of the housing or closing base. [0087] In another embodiment the handle 18 in location mounts the drive gear 43 within the housing 14 and with a locking pin extending from the closing base 20 to abut and thereby hold the curved lover formation and retain the handle 18 in a captured position and thereby lock the top elements of the chainwinder 12 to the closing base 20. [0088] The improvements in the heavy duty drive for a chainwinder can be used in varying chainwinders. One of those is the versatile short chain systems of the applicant as described in co-pending patents and patent applications, including Australian application no 2014100575, the contents of which are also hereby incorporated by reference. This also describes the operation of the handle to engage with the drive mechanism and selectively drive the chain in and out of the housing. [0089] While we have described herein particular embodiments of a chainwinder it is further envisaged that other embodiments of the invention could exhibit any number and combination of any one of the features previously described. However, it is to be understood that any variations and modifications which can be made without departing from the spirit of the invention are included in the scope thereof as defined in the following claims. Interpretation Embodiments: [0090] Reference throughout this specification to "one embodiment" or "an embodiment" means that a particuln feature, structure or characteristic described in connection with the embodiment is included in at least one embodiment of the presem invenion. Thus, appearances 17 of the phrases "in one embodiment or "in an embodiment" in various places throughout this specification are not necessarily all referring to the same embodimentbut may, Furtherore, the particular features, structures or characteristics may be combined in any suitable manner, as would be apparent to one of ordinary skill in the art from this disclosure, in one or more embodiments. [0091] Similarly it should be appreciated that in the above description of example embodiments of the invention, various features of the invention are sometimes grouped together in a single embodiment. figure. or description thereof for the purpose of streamlining the disclosure and aiding in the understanding of one or more of the various inventive aspects. This method of disdosurehowever, is not to be interpreted as reflecting an intentiordhat the claimed invention requires more features than are expressly recited in each claim Rather, as the flowing claims reflect, inventive aspects lie in less than all features of a single foregoing disclosed embodiment. Thus, the ciaimns following the Detailed Description of Specific Embodiments are hereby expressly incorporated into this Detaied Deription of Specific Embodiments with each claim standing on its own as a separate embodiment of this invention. [0092]| Furthernore, while some embodiments described herein include some but not other features included in other embodiments,combinations of features of different embodiments are meant to be within the scope of the invention, and form different embodiments. as would be understood by those in the art. For example, in the following claims, any of the claimed embodiments can be used in any combination. Different instances of Objects [0093] As used herein, unless otherwise specified the use of the ordinal adjectives "first", "second", "third", etc., to describe a common object, merely indicate that different instances of like objects are being referred to, and are not intended to imply that the objects so described must be in a given sequence, either temporary, spatially in ranking, or in any other manner Specific Details [0094] In the description provided herein, numerous specific details are set forth. However, it is understood that embodiments of the invention may be practiced without these specific details. In other instances, weli-known methods, structures and techniques have not been shown in detail in order not to obscure an understanding of this description.

18 Terminology [0095] in describing the preferred embodiment of the invention illustrated in the drawings, specific terminology will be resorted to for the sake of clarity However, the invention is not intended to be limited to the specific terms so selected, and it is to be understood that each specific term includes all technical equivalents which operate in a similar manner to accomplish a similar technical purpose. Terms such as "forward", rearward, radially", "peripherally upwardlyy", "downwardly", and the like are used as words of convenience to provide reference points and are not to be construed as limiting terms, Comprising and Including [0096] In the claims which follow and in the preceding description of the invention, except where the context requires otherwise due to express language or necessary implication, the word comprise" or variations such as "comprises or "comprising" are used in an inclusive sense, i.e. to specify the presence of the stated features but not to preclude the presence or addition of further features in various embodiments of the invention. [0097] Any one of the tenn including or which includes or that includes as used herein is also an open term that also means including at least the elements/features that follow the term, but not excluding others, 'Thus, including is synonymous with and means comprising. Scope of Invention [0098] Thus, while there has been described vhat arc believed to be the preferred embodiments of the invention, those skilled in the art will recognize that other and further modifications may be made thereto without departing fron the spirit of the invention, and it is intended to claim all such changes and modifications as fail within the scope of the invention, For example, any formulas given above are merely representative of procedures that may be used. Functionality may be added or deleted from the block diagrams and operations may be interchanged among functional blocks, [0099] Steps may be added or deleted to methods described within the scope of the present invention. [00100] Although the invention has been described with reference to specific examples, i will 19 be appreciated by those skilled in the art that the invenion may be embodied in many other forms. Industrial Applicability [00101] It is apparent from the above, that the arrangements described are applicable to the window and window hardware industries.

Claims (5)

1. A chainwinder comprising: a housing formed by a body and a metal base, to receive a chain therein; a drive mechanism engageable with the chain, to selectively drive the chain from the housing to alter the degree of openness of an attached window, the drive mechanism including at least one drive gear rotatable about an axis extending between respective ends of the drive gear, the drive gear being mounted relative to the body at a first end portion and mounted relative to the base plate at a second end portion; and a wear component mounted between the base and the second end portion of the drive gear.

2. The chainwinder of claim 1, wherein the wear component is formed of a softer material than the metal base.

3 The chainwinder of claim I or 2, wherein the wear component engages the second end portion of the drive gear along a bearing surface that extends longitudinally along the axis, and the length of the bearing surface is greater than the thickness of the base.

4. The chainwinder of any preceding claim, wherein the vear component comprises a bush nonrotatably mounted to the base and extending into a holein the base, the bush having a cylindrical hole therethrough, and wherein the second end of the drive gear is received within the cylindrical hole.

5 The chainwinder of any preceding claim, wherein the wear component is formed of a polymer