GB2588508A

GB2588508A - Belt transmission systems for a motorised roller assembly

Info

Publication number: GB2588508A
Application number: GB2013302.1A
Authority: GB
Inventors: Tuan Phan Anh; Jaber Hani; Jaber Simon
Original assignee: CiiLock Engineering Pty Ltd
Current assignee: CiiLock Engineering Pty Ltd
Priority date: 2019-08-26
Filing date: 2020-08-26
Publication date: 2021-04-28
Anticipated expiration: 2040-08-26
Also published as: AU2020223697A1; GB2588508B; GB202013302D0; GB202013303D0; AU2020223698A1; GB2588285A; GB2588285B

Abstract

The transmission system is for installation into the frame of a movable closure. The transmission system receives power produced from a motor to drive a wheel 44 associated with the closure. The transmission system including two belts 86, 88 on opposite sides of the wheel wherein the combined movement of the belts drives the wheel. Also claimed is a belt transmission system for installation within a frame where the system includes two pulleys, the pulleys having respective axis of rotation which are non-parallel to each other, the shortest distance between the pulleys is less than five times the diameter of the larger first pulley. Also claimed is a movable closure assembly with two pulleys that have non parallel axis of rotations.

Description

Belt transmission systems for a motorised roller assembly Field of the invention The present invention relates to belt transmission systems for installation within a frame of a movable closure. In particular, although not exclusively, the invention relates 5 to belt transmission systems utilised in a motorised roller system.

Background of the invention

In relation to movable closures, particularly in the sliding door industry for residential houses (e.g. aluminium and glass door panels), one of the issues encountered is the high operational force that users must apply to move the door. The high operational force is an inevitable consequence of door weight and the seal compression. Among various methods for reducing operational force of a sliding door, a powered roller is generally a desired approach.

Many powered sliding door systems (generally powered by electrical motors) have been designed and widely used in commercial buildings such as shops, showrooms, 15 company entrances, etc. Those systems normally have a large driving unit installed above and externally to the door panel However, the above type/method of door operation is not suitable for residential houses. One problem is that some prior art systems include rather bulky systems installed externally to the door panel. This is aesthetically unpleasant, particularly within a 20 residential house.

The transmission system of a motorised roller system normally utilises gear drives that include toothed gear wheels to solve the issue of rotation diversion between the motor and the driven wheel (which rotate about non-parallel axes), e.g. using worm gears. However these gear drives create high levels of noise, especially at high speed. Low noise is an important criterion in designing products for residential houses.

Also, gear transmissions depend heavily on continuous lubrication for quiet operation and durability (e.g. in car or milling machine transmission boxes). However, continuous lubrication in large gear transmissions is not feasible or at least not economical with sliding doors having rollers in the lower rail of the door frame as they are exposed to dust and water and require regular maintenance. Metal gear transmissions in particular are susceptible to corrosion upon exposure to water and moist conditions. This can adversely affect the performance of the gears by increasing the level of noise generated and increase the likelihood of the gears jamming.

Thus, it would be desirable to provide a belt transmission system that overcomes or at least ameliorates one or more of the above-mentioned problems. Alternatively to the above, it would be desirable to provide a belt transmission system which provides a design choice over those systems known in the prior art.

Reference to any prior art in the specification is not an acknowledgment or suggestion that this prior art forms part of the common general knowledge in any jurisdiction or that this prior art could reasonably be expected to be understood, regarded as relevant, and/or combined with other pieces of prior art by a skilled person in the art.

Summary of the invention

In a first aspect, the present invention provides a transmission system for installation within a frame of a movable closure, the transmission system configured to receive power produced by a motor to drive a wheel associated with the movable closure, the transmission system including a first belt arranged on a first side of the wheel and a second belt arranged on a second, opposing side of the wheel, wherein the combined movement of the first and second belt drive the wheel.

It is to be understood that a belt is a loop of flexible material generally used to link two or more rotating shafts mechanically. Thus, for example, references to belts herein can include ropes, toothed belts, and other suitable variations.

Advantageously, the present invention provides a transmission system that can drive a wheel of a motor-driven movable closure using two suitably positioned belts on either side of the wheel. The use of belts in the transmission system provides for a relatively quieter transmission system, particularly compared to transmission systems that largely rely on large gearing arrangements. Belts are also significantly less affected than metal gear transmissions to water or moisture exposure, and thus the present invention provides a transmission system that has improved water resistance properties.

A further advantage of the present invention is the ability to implement such a double belt arrangement, capable of moving the wheel of the movable closure, within the frame of the movable closure. Frames of movable closures present very limited space to implement suitable transmission systems. The present invention makes use of the limited space in the frame, either side of the wheel, to drive the wheel using the first and second belt.

In an embodiment, the wheel is a conventional or main driven wheel of the movable closure.

In one embodiment, the first and second belts are arranged substantially symmetrically about an axis of travel of the wheel. This ensures smooth and continuous rotation of the wheel when the first and second belt are moving. Preferably, the first and second belt are substantially identical in at least one of the following properties: length, material, cross-section size, shape and size of teeth (in the case of a toothed belt).

In one embodiment, a first drive receiving groove is provided adjacent the first side 15 of the wheel and a second drive receiving groove is provided adjacent the second side of the wheel, wherein the first belt operatively engages the first drive receiving groove and the second belt operatively engages the second drive receiving groove.

In one embodiment, the first and second drive receiving grooves are provided on first and second drive pulleys that rotate synchronously with the wheel. The first and 20 second drive pulleys may be separate to the wheel, or integrally formed with the wheel.

In one embodiment, the transmission system may include a twisted belt drive in accordance with the below described second aspect of the invention.

In one embodiment, the transmission system includes a bevel-gear arrangement configured to be operatively coupled to the motor, the bevel-gear arrangement configured to receive an input from the motor and produce an output that causes movement of the first and second belt. Advantageously, this form of hybrid transmission system that utilises both a bevel-gear arrangement and double belt arrangement provides reduction in noise and maintenance relative to a pure gear transmission system.

In one embodiment, the bevel-gear arrangement includes a gear housing whereby the gear housing and a first transmission pulley laterally overlap. The first transmission pulley supports the first belt of the transmission system.

In a preferred form, the gear housing has an opening to permit passage of an 5 output shaft of the bevel-gear arrangement, wherein the output shaft extends in a direction substantially orthogonal to the axis of travel of the wheel.

In one embodiment, a first transmission pulley is mounted to the output shaft, wherein rotation of the first transmission pulley facilitates movement of the first and second belt.

In one embodiment, the housing defines a recess surrounding the opening of the housing, the recess configured to receive therein at least a portion of the first transmission pulley. The portion of the first transmission pulley is preferably sized to permit the first transmission pulley to be at least partially disposed in the recess without preventing rotation thereof. Advantageously, this overlapping arrangement between the first transmission pulley and the gear housing results in the first transmission pulley being located along or laterally closer to a longitudinal axis substantially in line with the axis of travel of the wheel. This can simplify the transmission system by facilitating the implementation of the double belt arrangement with a minimal number of components.

For example, the transmission system may include a second transmission pulley in rotational relation with the first transmission pulley. The rotational relationship between the first and second transmission pulleys may be provided by a third belt operatively engaged with the first and second transmission pulley. In an embodiment, the first and second belts are operatively engaged with the second transmission pulley, wherein movement of the second transmission pulley causes movement of the first and second belts to drive the wheel.

In another aspect, the present invention provides a movable closure incorporating the transmission system as described above. The transmission system may be provided as new. Alternatively, the transmission system may be retrofitted into an existing closure.

Any of the features described in connection with other aspects of the invention may 30 be incorporated into this aspect of the invention.

In a second aspect, the present invention provides a belt transmission system for installation within a frame of a movable closure, the belt transmission system including a first pulley, a second pulley and a belt operatively engaged with the first and second pulleys, the first pulley having a first axis of rotation and the second pulley having a second axis of rotation, the first axis of rotation and the second axis of rotation being nonparallel to one another, wherein the shortest centre to centre distance between the first and second pulleys is less than about 5 times the diameter of the larger of the first and second pulleys or the diameter of the first or second pulley where the diameters are the same.

Advantageously, this aspect of the invention provides a belt transmission system that is suitable for applications that have limited spacing for the components of the belt transmission system. Ordinarily, such limited space applications are provided with alternative transmission arrangements, such as gearing arrangements that utilise bevel gears, worm gears, etc. However, such arrangements can suffer from high level of noise, the need for continuous lubrication, and regular maintenance. The present aspect of the invention solves one or more of these issues by providing a suitably constructed belt transmission system.

Any of the features described in connection with other aspects of the invention may be incorporated into this aspect of the invention.

In a third aspect, the present invention provides a movable closure assembly, including a frame and a belt transmission system including a first pulley, a second pulley and a belt operatively engaged with the first and second pulleys, the first pulley having a first axis of rotation and the second pulley having a second axis of rotation, the first axis of rotation and the second axis of rotation being non-parallel to one another, wherein the belt transmission system is fully or substantially contained within the frame.

Such an assembly is particularly useful for a movable closure assembly that includes a motorised roller system. Motorised roller systems often include a motor having a shaft axis that extends parallel to the elongation of the frame (e.g. the upper rail, lower rail or stiles). The output of the motor generally needs to be diverted orthogonally in order to drive the driven wheel of the motorised wheel assembly that has its axis of rotation at 900 to the shaft axis of the motor. However, the diversion can be other angles, such as 300, 45° or 60°.

Advantageously, this aspect of the invention includes a belt transmission system that can be fitted in the limited space provided for in the frame of a movable closure.

Further, as described for the second aspect, this aspect of the invention provides a movable closure assembly that can operate with a reduced level of noise (particularly beneficial in a residential setting), does not require lubrication, and does not require regular maintenance.

According to either of the two aspects above, the belt transmission system may include one or more guiding structures disposed between the first and second pulleys, wherein the one more guiding structures are configured to prevent or reduce the possibility of the belt slipping from engagement with the first and second pulleys. The one or more guiding structures may be arranged to pinch or guide the crossing belts (between the two pulleys) towards each other. For example, the one or more guiding structures may be in the form of two spaced guides. More specifically, the one or more guiding structures can be in the form of two alignment pins disposed between the first and second pulleys and arranged on opposite sides of the belt. In one embodiment, the guiding structures can be in the form of one or more guiding structures, such as one or more, for example two, alignment pins that are rotationally mounted to the frame or to a housing fitted to the frame. Advantageously, having the alignment pins rotationally mounted reduces friction between the alignment pins and the belt.

According to either of the two aspects above, the belt transmission system may include a third pulley, and a second belt operatively engaged with the second and third pulleys, the third pulley having a third axis of rotation, the third axis of rotation being non-parallel to the first and second axis of rotation. In one embodiment, the first axis of rotation and third axis of rotation are substantially orthogonal to one another.

Advantageously, a multi-tiered twisted belt system, in the above example a two-tiered system, can be employed to divert orthogonally the drive provided by the motor to a driven wheel.

The movable closure recited in the aspects and embodiments of the invention described above can be of any suitable type, such as a door, windows, gate, etc. The 5 closures may slide or swing. The closure may move horizontally, i.e. between left and right, vertically, i.e. between up and down, or swing.

As used herein, except where the context requires otherwise, the term "comprise" and variations of the term, such as "comprising", "comprises" and "comprised", are not intended to exclude further additives, components, integers or steps.

Further aspects of the present invention and further embodiments of the aspects described in the preceding paragraphs will become apparent from the following description, given by way of example and with reference to the accompanying drawings.

Brief description of the drawings

Figure 1 is a perspective view of a movable closure in accordance with one 15 embodiment of the present invention; Figure 2 is a partial perspective view of the movable closure of Figure 1 showing some components of a motorised roller system assembly in accordance with one embodiment of the present invention; Figure 3 is a front view of a motorised wheel assembly in accordance with one 20 embodiment of the present invention; Figure 4 is a front perspective view of the motorised wheel assembly of Figure 3 without the housing; Figure 5 is a top view of the motorised wheel assembly of Figure 4; Figure 6 is a front view of the motorised wheel assembly of Figure 4; Figure 7 is a bottom view of the motorised wheel assembly of Figure 4; Figure 8 is a rear perspective view of the belt drive of the motorised wheel assembly of Figure 4; Figure 9 is an exploded rear perspective view of the belt drive of the motorised wheel assembly of Figure 4; Figure 9A is a front perspective view of another embodiments of a motorised wheel assembly without the housing; Figure 9B is a front view of the motorised wheel assembly of Figure 9A; Figure 9C is a top view of the motorised wheel assembly of Figure 9A; Figure 9D is a partial top section view of a bevel gear arrangement of the motorised wheel assembly of Figure 9A; Figure 9E is a front perspective view of the bevel gear arrangement of Figure 9D; Figure 9F is a rear perspective view of a pulley for engagement with the bevel gear arrangement of Figure 9D; Figure 10 is a perspective view of the twisted belt part of the belt drive of an embodiment of the present invention; Figure 11 is a perspective view of the twisted belt part of the belt drive of an 15 alternative embodiment of the present invention; Figure 12 is a section view showing a twisted belt of a belt drive within a lower rail in accordance with an embodiment of the present invention; Figure 13 is a rear perspective view of a twisted belt drive of a motorised wheel assembly of another embodiment of the present invention'; Figure 14 is a top view of the twisted belt drive of Figure 13; and Figure 15 is a front view of the twisted belt drive of Figure 13 Detailed description of the embodiments Movable closure Referring to Figures 1 and 2, there is provided a movable closure, which in this 25 embodiment is in the form of a sliding door 10. As used herein, the vertical direction is to be understood in reference to the direction coinciding with the height dimension of the door 10, whilst front, rear, left side and right side will be understood in reference to the view shown in Figure 1.

The door 10 includes a series of extrusions that define the frame of the door 10. 5 The frame includes a lower rail 12, an upper rail 14, leading stile 16, and trailing stile 18. Held within the frame components is glass panel 11. The door 10 further includes a handle 20 mounted on the leading stile 16 on which a user applies a force to move the door 10 between open and closed positions (and positions in between). It is to be understood for the depicted example that when a user applies a force on the handle 20 10 substantially towards the right, the door 10 will move in the opening direction, whereas when a user applies a force on the handle 20 substantially towards the left, the door will move in the closing direction.

Motorised wheel assembly As can be seen in Figure 2, a motorised wheel assembly 40 is fitted into the lower rail 12 of the door 10, with wheels 44, 46 designed to engage a track (not shown) underneath the door 10. Fitted within the leading stile 16 is a power supply 22 and a control unit 24. The power supply provides power to one or more components of the handle 20 and the motorised roller 40. However, this is only one of a large number of possible implementations, as the motorised wheel assembly 40, the power supply 22 and the control unit 24 may be fitted in other parts of the door's frame. For example, in the case of a window or door that is intended to move in the vertical direction, the motorised wheel assembly may be contained in one or both of the trailing stile and leading stile.

The control unit 24 is operatively associated with handle 20 and motorised wheel assembly 40. One possible implementation, described in a co-pending application of the Applicant that claims priority from Australian provisional application 2019903119 (both of which are incorporated herein by reference), involves the control unit 24 being configured to receive a signal from the handle 20 when a suitable user applied force is detected. The control unit 24 then sends a signal to the motorised wheel assembly 40 in order to provide powered assistance for the opening or closing of the door 10. The signals may be sent between the components by any suitable wired or non-wired manner.

Referring to Figures 3-7, which depict one embodiment of the motorised wheel assembly 40, it will be appreciated that the motorised wheel assembly 40 incorporates similar features to that disclosed in the Applicant's earlier international patent specifications W02011/100788, W02015/017878 and W02017/075669. The disclosures of these earlier specifications are hereby incorporated by reference.

The motorised wheel assembly 40 is substantially contained within a housing 42 (shown transparent in Figure 3), which is fitted in this example into the lower rail 12. The motorised wheel assembly 40 includes a motor 48, which drives a drive mechanism in the form of a belt drive 60, which in turn drives driven wheel 44. Driven wheel 44 is engaged with the wheel path, which in most cases is a track underlying the door 10. The driven wheel 44 is carried by a wheel carrier 54. A passive wheel 46 is also provided to help distribute the weight of the door 10. The passive wheel 46 is housed in the passive wheel carrier 56. The position of the wheel axes of the wheels 44, 46 are adjustable relative to the housing 42. This provides for selective height adjustment, self-levelling and load sharing as is explained in detail in the Applicant's earlier international patent specification W02017/075669, which is incorporated herein by reference. In short, the wheel carriers 54, 56 cooperate with separation member 58 and the slidable end constraint 30 to allow for selective height adjustment and self-levelling. Motor

The motor 48 has a cylindrical body and is connected to a planetary gear drive 52.

The planetary gear drive 52 and the belt drive 60 assist in reducing the speed of the overall drive system, which will be appreciated by a person skilled in the art as increasing the torque produced at the driven wheel 44. However, it is to be noted that the planetary gear drive 52 is optional, and that the belt drive 60 may be driven directly by motor 48, with the belt drive 60 adjusted accordingly to meet the requirements of a given design. The planetary gear drive 52 is mounted to a motor bracket 55 as best shown in Figure 4. The motor bracket 55 is formed from a series of connected block-shaped members that support on one end the planetary gear drive 52 and on the other end components of the belt drive 60. The motor bracket 55 is mounted to housing 42 by a number of fastening members (not shown) and includes an aperture, from which the output shaft (not shown) of the planetary gear drive 52 projects for engagement with the belt drive 60.

It will be appreciated that the motor 48 produces rotational motion about an axis which is substantially parallel to the wheel path traversed by wheels 44, 46, this rotational motion being received by the planetary gear drive 52 as an input. The planetary gear drive 52 itself then produces rotational motion about the axis of its output shaft and this 5 axis is also substantially parallel to the wheel path traversed by wheels 44, 46. Thus, one of the functions of the belt drive 60 is to convert the rotational motion about the axis of the shaft of the motor 48 and planetary gear drive 52 to rotational motion in a direction substantially orthogonal thereto, in order to drive driven wheel 44. Secondly, the function of the belt drive 60 is to further bring about a reduction in speed for the output of the belt 10 drive 60. The principles of belt and pulley drive design are well known by those skilled in the art and need not be explained further here.

Belt drive Belt drive 60 will now be described with particular reference to Figures 8 and 9. It is noted that belt drive 60 provides at least two unique belt design arrangements that can be used alone or in combination as part of a suitable belt drive 60. It will be appreciated that the implementation of a belt drive, such as belt drive 60, in the limited space provided by the door frame (the lower rail 12 in the described embodiment) is a very difficult task. This is particularly so because of the fact that the output shaft of the motor 48 rotates about the longitudinal axis of the lower rail 12 and the output at the driven wheels 44 needs to be orthogonal to this. Further, as driven wheel 44 needs to engage the underlying track, the positioning of driven wheel 44 within the overall motorised assembly is dictated by the position of the track, i.e. driven wheel 44 is generally required to be positioned about half way between the front and rear sides of lower rail 12 in order to engage with the track. Thus, the amount of space either side of driven wheel 44 for any drive members is limited.

The inventors have managed to successfully design a belt drive that can be fully or substantially contained within the door frame and achieve the required performance objectives. For example, the belt drive can operate with a reduced level of noise (particularly beneficial in a residential setting), and in certain embodiments will not require lubrication or regular maintenance. Belt drives also have improved water resistance relative to metal gear drives, which are susceptible to corrosion upon exposure to water and other moist conditions.

Double belt arrangement The first of these unique belt design arrangements utilises a double-belt 5 arrangement to drive driven wheel 44. As will be appreciated by a person skilled in the art, space constraints are a major limiting factor in the design of drive/transmission systems installed within the frame of door 10. As the driven wheel 44 generally consumes a great deal of space (in the front to rear direction) within the frame and requires a suitable amount of torque in order to move door 10, there is a requirement that the transmission 10 system is capable of being installed in the limited space afforded by the door frame and that the transmission system be capable of transferring the necessary amount of torque to driven wheel 44. The double-belt arrangement, which will be described in more detail below as part of belt drive 60, ensures that the necessary amount of torque is provided to the driven wheel 44 by utilising two belts to drive the driven wheel 44.

First double belt arrangement As shown in Figures 8 and 9, there is mounted on the output shaft of the planetary gear drive 52 a motor pulley 62, which is the first pulley of the belt drive 60. Motor pulley 62 receives in a groove thereof a first end of twisted belt 64 (best seen in Figures 10 and 11). The second end of twisted belt 64 is received in rear groove 63 of double-grooved pulley 66. Shaft 61 of pulley 66 is journaled by a suitable bearing in housing 42. The axis of rotation of pulley 66 is orthogonal, i.e. 90°, to the axis of rotation of motor pulley 62.

Pulley 66 receives in front groove 65 thereof a first end of belt 68. The second end of belt 68 is received in groove 71 of pulley 72. It will be appreciated that belt 68, when viewed from above, is offset towards the front of the lower rail 12 relative to an axis of travel of driven wheel 44. Pulley 72 is rotationally mounted on shaft 74, on which is also rotationally mounted pulley 76, both of which are journaled by suitable bearings in housing 42. Thus, pulleys 72, 76 rotate together with shaft 74.

Pulley 76 receives in groove 73 thereof a first end of belt 78. The second end of belt 78 is received in central groove 81 of triple-grooved pulley 82. Shaft 67 of pulley 82 30 is journaled by a suitable bearing in housing 42. It will be appreciated that belt 78, when viewed from above, is substantially aligned with the axis of travel of the driven wheel 44. This enables belt 78, upon rotation, to provide a balanced rotational load to triple-grooved pulley 82 through the engagement of belt 78 with central groove 81. Further, and more importantly, the location of belt 78 provides sufficient space on either side of driven wheel 44 for accommodating the double belt arrangement.

Pulley 82 receives in rear groove 83 thereof a first end of belt 86. Belt 86 will be understood as one of the two belts that form the unique double-belt arrangement. The second end of belt 86 is received in groove 91 of rear pulley portion 77, which is integrally formed with driven wheel 44. Similarly, pulley 82 receives in front groove 84 thereof a first end of belt 88. Belt 88 will be understood as the other of the two belts that form the unique double-belt arrangement. The second end of belt 88 is received in groove 93 of front pulley portion 79, which is also integrally formed with driven wheel 44. It will be appreciated that pulley portions 77, 79 may be separate pulleys and need not be integrally formed with driven wheel 44.

Belts 86 and 88 of the double-belt arrangement are substantially identical and arranged symmetrically on either side of driven wheel 44. This symmetry ensures that the driven wheel 44 is rotated smoothly in order to ensure and maintain suitable engagement between the driven wheel 44 and underlying track. It is noted that slippage avoidance between the driven wheel 44 and track can be implemented through acceleration or speed control of motor 48.

Whilst the above belt drive has been found to be suitable, alternative belt drive configurations may be used that deliver the necessary torque requirements of the overall drive system. One suitable transmission ratio is 32.4:1, wherein the planetary gear drive 52 provides a transmission ratio of 6.7:1, pulley 72 to pulley 66 provides a transmission ratio of 32:15, and pulleys 77,79 to pulley 82 provides a transmission ratio of 34:15. Other suitable transmission ratios can be provided.

Whilst a toothed belt and pulley system has been used in the depicted embodiment, it will be appreciated that the belt and pulley implementation of this drive system can be a non-toothed belt and pulley system.

Selective height adjustment and self-levelling The axis of rotation 45 of the wheel 44 is adjustable relative to the housing 42 to enable selective height adjustment and self-levelling. This is explained in detail in the Applicant's already incorporated earlier international patent specification W02017/075669. The same principles apply here but with a belt drive.

Second double belt arrangement Reference is now made to Figures 9A to 9C that illustrate another embodiment of a motorised wheel assembly 300 that utilises a double-belt arrangement. In some, generally more heavy-duty, applications, the overall drive system may be provided with a bevel-gear arrangement 310 instead of a twisted belt arrangement between motor 348 and driven wheel 344. As previously mentioned, it will be appreciated that the motorised wheel assembly 300 incorporates similar features to that disclosed in the Applicant's earlier international patent specifications as previously specified and incorporated by reference. It will also be appreciated by a person skilled in the art that many of the features of this embodiment are the same as or very similar to the features of the earlier embodiments and therefore require minimal further explanation.

The motorised wheel assembly 300 is substantially contained within a housing (not shown), which is fitted in this example into the lower rail 12. The motorised wheel assembly 300 includes motor 348, which drives a transmission system that includes both the bevel gear arrangement 310 and belt drive 360, which in turn drives driven wheel 344.

Driven wheel 344 is engaged with the track underlying the door 10 as was the case in the previous embodiment. The driven wheel 344 is carried by a wheel carrier 354. A passive wheel 346 is also provided to help distribute the weight of the door 10. The passive wheel 346 is housed in the passive wheel carrier 356. The position of the wheel axes of the wheels 344, 346 are adjustable relative to the housing. This provides for selective height adjustment, self-levelling and load sharing as previously explained.

The motor 348 has a cylindrical body and is connected to a planetary gear drive 352. The planetary gear drive 352, the bevel gear arrangement 310, and the belt drive 360 assist in reducing the speed of the overall drive system, which will be appreciated by a person skilled in the art as increasing the torque produced at the driven wheel 344.

Again, the planetary gear drive 352 is optional, and the bevel gear arrangement 310 may be driven directly by motor 348, with the bevel gear arrangement 310 and belt drive 360 adjusted accordingly to meet the requirements of a given design.

The planetary gear drive 352 is mounted to a motor bracket 355 as best shown in Figure 9A. The motor bracket 355 is a substantially planar, square body that supports at 5 one end the planetary gear drive 352 and at the other end a coupling element 308. The coupling element 308 couples the output shaft (not shown) of the planetary gear drive 352 with an input shaft 314 of the bevel gear arrangement 310. The motor bracket 355 is mounted to the housing by a number of fastening members (not shown) and includes an aperture, from which the output shaft (not shown) of the planetary gear drive 352 projects 10 for operative engagement with the bevel gear arrangement 310 through coupling 308.

It will be appreciated that motor 348 produces rotational motion substantially parallel to the wheel path traversed by wheels 344, 346, this rotational motion being received by the planetary gear drive 352 as an input. The planetary gear drive 352 itself then produces rotational motion about the axis of its output shaft and this axis is also substantially parallel to the wheel path traversed by wheels 344, 346. Thus, one of the functions of the bevel gear arrangement is to convert the rotational motion about the axis of the shaft of the motor 348 and planetary gear drive 352 to rotational motion in a direction substantially orthogonal thereto, in order to ultimately drive driven wheel 344. Secondly, the function of the bevel gear arrangement 310 and the belt drive 360 is to further bring about a reduction in speed for the output of the belt drive 360.

The bevel gear arrangement 310 will now be described with particular reference to Figure 9D. As will be appreciated, the bevel gear arrangement 310, like the twisted belt arrangement, transforms rotation about the longitudinal axis of the lower rail 12 provided by the motor 348 into rotation about an axis orthogonal to the longitudinal axis of the lower rail 12 in order to rotate the driven wheel 344. Bevel gear arrangement 310 includes a substantially L-shaped housing 312, the housing conforming substantially to the gear arrangement therein. The housing 312 includes a right-side opening 316, adjacent coupling element 308, for permitting passage of the input shaft 314 of the bevel gear arrangement 310. The input shaft 314 extends about the longitudinal axis of the lower rail 12 and is suitably journaled with the housing 312 to permit rotation of the input shaft 314 but prohibit translation thereof. Mounted at an inner end of the shaft 314 is a pinion 318.

Pinion 318 rotates about an axis parallel with the longitudinal axis of shaft 314 and is operatively engaged with gear 320. Gear 320 is mounted at a rear end of output shaft 322, which extends orthogonal to the longitudinal axis of the shaft 314 and is suitably journaled with the housing 312 to permit rotation of the output shaft 322 but prohibit translation thereof. It will be appreciated that the gear 320 and pinion 308 can be mounted to their respective shafts by a standard keyed arrangement. Alternatively, one or both of gear 320 and pinion 308 may be integrally formed with their respective shafts, thus eliminating the need for separate assembly of the gear and pinion with its respective shaft.

The housing 312 includes a front-side opening 324 for permitting passage of the output shaft 322 of the bevel gear arrangement 310. Each of the input and output shafts of the bevel gear arrangement are provided with a suitable oil seal ring in order to ensure that the housing is satisfactorily liquid sealed to prevent any lubricating fluid from leaking out of the housing and to stop any debris or contaminants entering the housing.

As best shown in Figure 9E, front wall 326 of housing 312 includes a circular recess 328 surrounding front-side opening 324. Recess 328 is configured to at least partially receive a rear, complementarily shaped surface 330 of a pulley 362 (Figure 9F) configured to be mounted on the output shaft 322 and act as the first pulley 362 of the belt drive 360. When the first pulley 362 is brought into position at least partially within the recess 328 of the housing 312 (so that at least a portion of the housing 312 overlaps the first pulley 362 when viewed along the vertical direction), the first pulley 362 is still permitted to rotate relative to the housing 312 (via output shaft 322), and, importantly, the first pulley 362 is positioned closer to the axis of travel of the driven wheel 344. Without such an overlapping arrangement between the first pulley 362 and housing 312 enabled by the recess 328 and complementarily shaped surface 330 of the first pulley 362, the first pulley would be disposed more forward, and thus lie along a longitudinal axis parallel to, but offset from the axis of travel of the driven wheel 344. This would necessitate additional pulleys and belts, extending the length of the overall drive system, in order to satisfactorily implement the double-belt arrangement.

Recess 328 can be created in housing 312 in any suitable manner known in the 30 art. For example, a suitable portion of front wall 326 can be removed in order to create recess 328, or the housing 312 can be suitably cast with recess 328. Similarly, the complementarily shaped surface 330 of pulley 362 can be formed in any suitable manner known in the art, such as by machining the complementarily shaped surface onto one side of a standard pulley.

In relation to belt drive 360 of this embodiment, first pulley 362 receives in a groove 363 thereof a first end of belt 364. The second end of belt 364 is received in central groove 381 of triple-grooved interim pulley 382. Interim pulley 382 is mounted on shaft 367 and is journaled by a suitable bearing in the housing. Interim pulley 382 receives in rear groove 383 thereof a first end of belt 386. Belt 386 will be understood as one of the two belts that form the double-belt arrangement. The second end of belt 386 is received in groove 391 of rear pulley portion 377, which is integrally formed with driven wheel 344. Similarly, interim pulley 382 receives in front groove 384 thereof a first end of belt 388. Belt 388 will be understood as the other of the two belts that form the double-belt arrangement. The second end of belt 388 is received in groove 393 of front pulley portion 379, which is also integrally formed with driven wheel 344. It will be appreciated that pulley portions 377, 379 may be separate pulleys and need not be integrally formed with driven wheel 344.

As will be appreciated, the bevel gear arrangement 310 combined with the overlapping arrangement between the first pulley 362 and the bevel gear housing 312 ultimately simplifies the belt drive 360. This is because the belt drive 360 can be implemented with only three belts, with a single belt 364 driving the interim pulley 382, which ultimately carries the double belts 386, 388 and drives the driven wheel 344. Another advantage of this simplified design is the ability to reduce the overall length of the motorised roller assembly, that otherwise would need extending with further intermediate belts and pulleys to allow for the double-belt arrangement that drives the driven wheel 344. Other advantages associated with this embodiment of the invention includes greater durability, improved water proofing due to the sealed bevel gear housing 312, and the reduction of noise provided by a transmission system that utilises in part a belt drive relative to other forms of transmission systems (for example, an entire gear transmission system).

First twisted belt arrangement Reverting to the first of the double belt arrangements, briefly touched upon earlier, is the utilisation of a twisted belt arrangement in the belt drive 60. As mentioned previously, there is a need to convert the torque provided by the motor, where the output shaft thereof rotates about the axis of travel of the wheel, by approximately 90° in order to turn the drive wheel, which has an axis of rotation orthogonal to its axis of travel. Conventionally, particularly in applications such as motorised roller systems, various types of gear arrangements are utilised in order to make this conversion.

However, this embodiment has been designed to utilise a twisted belt arrangement in order to achieve this conversion as best shown in Figures 10 and 11. The implementation of a twisted belt 64 in such a limited space goes against conventional design wisdom because of the necessary dimensions of the pulleys and the expected load to be experienced by the twisted belt 64.

Conventionally, one general rule of thumb is that the centre to centre distance between two pulley wheels should be at least 5 * (D+W), where D is the diameter of the larger pulley (or one of the pulleys if the pulleys are of the same size) and W is the belt width. However, the inventors have managed to construct a belt transmission system that can be sized so that the centre to centre distance between the two pulleys is less than or equal to 5 times the diameter of the largest pulley (or the diameter of one of the pulleys in the event the diameters are equal). Thus, the twisted belt 64 of the belt drive 60 can have the centre to centre distance between pulleys 62 and 66 be smaller than is conventionally used, thereby allowing such a belt drive 60 to be used in a limited space application such as the one described in relation to the door 10.

In high load or high speed applications, the bending/twisting moment in the twisted belt 64 increases, and the general force in the twisted belt will tend to force the twisted belt off of the pulleys. Further support in such application can be provided to the twisted belt 64 in order to ensure that it maintains engagement with pulleys 62 and 66. One form of support can be provided by alignment pins 96 as shown in Figure 11. Alignment pins 96 are mounted either rotationally or non-rotationally to housing 42 and are disposed between pulleys 62 and 66, on either side of twisted belt 64. The alignment pins 96 can pinch or guide the crossing belts between the two pulleys towards each other. In some applications, it is preferable for the alignment pins 96 to be rotationally mounted, for example, to a frame or a housing fitted to the frame of the closure. This reduces friction between the alignment pins 96 and the belt, particularly as high load or high speed applications can experience a significant level of rubbing between the twisted belt 64 and the alignment pins 96.

Reference is now made to Figure 12, which shows lower rail 12 with pulleys 62 and 66 carrying twisted belt 64. Lower channel 110 of lower rail 12 provides a constrained design space in which the twisted belt 64 can be implemented as part of the belt drive 60. The height of the lower channel 110 must be greater than the centre to centre distance of pulleys 62, 66 and the radius of each pulley. This can be expressed generally to apply to any two pulleys used in such an arrangement by the following inequality: C + (r + R) < H (d + D) C+ <H where: C = centre to centre distance between the two pulleys; d = diameter of smaller pulley; (pulley 62 in this example) D = diameter of larger pulley; (pulley 66 in this example) H = height of lower channel.

The design assumptions made are that the worst case scenarios are where the pulleys are of the same diameter, along with the centre to centre distance between the two pulleys being some multiple of the diameter of the pulleys. This can be expressed 20 generally as follows: (d + D) Assume C = n* d (worst case) => n* d + < H If d =D (worst case) => (n + 1)* d <H n < -1 (1) where: n = the number of times the diameter of the larger of the first and second pulleys (or the diameter of the first or second pulley where the diameters are the same).

One example of a standard lower rail extrusion includes a height of the lower 5 channel (H), such as lower channel 110, of 48 mm, with the use of a pulley of minimum diameter 8 mm. Based on the inequality (1) this provides: nc--i =5 Thus, the shortest centre to centre distance between the first and second pulleys 10 is less than about 5 times the diameter of the largest pulley.

In order to provide some clearance between the pulleys and ceiling of the lower channel of the lower rail, and to factor in the flanges of the pulleys, which are generally at least about 0.5 mm larger than the pulley in radius, the same inequality can be utilised with H=46 mm and d = 9 mm. This will provide n <4.1. Thus, the shortest centre to centre distance between the first and second pulleys is less than about 4.1 times the diameter of the largest pulley in this example. These pulley sizes are significantly smaller than those being conventionally used in typical belt drives.

Second twisted belt arrangement Another embodiment of a suitable twisted belt drive is provided in Figures 13 to 15. Unlike the twisted belt 64 in the embodiment of Figures 9 to 10, where the arrangement enabled a one-step conversion of the rotational motion about the axis of the shaft of the motor 48 and planetary gear drive 52 to rotational motion in a direction substantially orthogonal thereto in order to drive driven wheel 44, the current embodiment uses a multi-step or multi-tiered approach to convert the rotational motion about the axis of the shaft of the motor 248 and planetary gear drive 252 to rotational motion in a direction substantially orthogonal thereto. In the embodiment depicted in Figures 13 to 15, a two-step approach has been utilised.

Mounted on the output shaft of the planetary gear drive 252 is a motor pulley 262, which is the first pulley of the belt drive 260. Motor pulley 262 receives in a groove thereof a first end of a first twisted belt 264. The second end of first twisted belt 64 is received in rear groove 263 of double-grooved pulley 266, which is mounted at an angle of about 30° 5 to the horizontal of the axis of rotation of the motor shaft as best shown in Figure 14. Shaft 261 of pulley 266 is journaled by a suitable bearing in the housing (not shown). Thus, the axis of rotation of pulley 266 is about 30° to the axis of rotation of motor pulley 262. Pulley 266 receives in front groove 265 thereof a first end of second twisted belt 268. The second end of second twisted belt 268 is received in front groove 271 of double-grooved pulley 10 272. Pulley 272 is rotationally mounted on shaft 274, and is journaled by suitable bearings in the housing. It will be appreciated that the axis of rotation of pulley 272 is rotated about 60° to the horizontal of the axis of rotation of pulley 266. Thus, the axis of rotation of pulley 272 is substantially orthogonal, i.e. 90°, to the axis of rotation of motor pulley 262.

Implementation of the twisted belt arrangement in this multi-stepped approach means that the overall bending/twisting moment experienced by each twisted belt is less than in the case of using a single twisted belt to convert the rotational motion about the axis of the shaft of the motor 48 and planetary gear drive 52 to rotational motion in a direction substantially orthogonal thereto. It will be appreciated that many of the advantages already discussed regarding the twisted belt arrangement generally apply in this embodiment. Alignment pins, such as alignment pins 96, can also be used in this embodiment if desired.

The components used in the various embodiments described above should be suitable for their given application. For example, it is generally ideal for the components to be water resistant and/or corrosion resistant to withstand wet environments. Most of the components are either made of suitable metals, such as anodised aluminium, stainless steel, zinc, etc, or suitable plastic or polymer materials, such as hard plastics, nylon, etc. The belts may be made from any suitable material known in the art. For example, the belt may be made from a suitable rubber. One example is neoprene. This can be further reinforced with a suitable fibre material such as fibre glass or Kevlar.

It will be understood that the invention disclosed and defined in this specification extends to all alternative combinations of two or more of the individual features mentioned or evident from the text or drawings. All of these different combinations constitute various alternative aspects of the invention.

Claims

CLAIMS1. A transmission system for installation within a frame of a movable closure, the transmission system configured to receive power produced by a motor to drive a wheel associated with the movable closure, the transmission system including a first belt arranged on a first side of the wheel and a second belt arranged on a second, opposing side of the wheel, wherein the combined movement of the first and second belt drive the wheel.
2. The transmission system of claim 1, wherein the wheel is a conventional or main driven wheel of the movable closure.
3. The transmission system of claim 1 or 2, wherein the first and second belts are arranged substantially symmetrically about an axis of travel of the wheel.
4. The transmission system of any one of the preceding claims, wherein the first and second belts are substantially identical in at least one of the following properties: length, material, cross-section size, shape and size of teeth (in the case of a toothed belt).
5. The transmission system of any one of the preceding claims, wherein a first drive receiving groove is provided adjacent the first side of the wheel and a second drive receiving groove is provided adjacent the second side of the wheel, and wherein the first belt operatively engages the first drive receiving groove and the second belt operatively engages the second drive receiving groove.
6. The transmission system of claim 5, wherein the first and second drive receiving grooves are provided on first and second drive pulleys that rotate synchronously with the wheel.
7. The transmission system of any one of the preceding claims, wherein the transmission system includes a bevel-gear arrangement configured to be operatively coupled to the motor, the bevel-gear arrangement configured to receive an input from the motor and produce an output that drives movement of the first and second belt.
8. The transmission system of claim 7, wherein the bevel-gear arrangement includes a gear housing.
9. The transmission system of claim 7 or 8, wherein a first transmission pulley is mounted to the output of the bevel gear arrangement, wherein rotation of the first transmission pulley facilitates movement of the first and second belt.
10. The transmission system of claim 9, wherein the bevel gear arrangement includes a gear housing defining a recess which is configured to receive therein, at least a portion of the first transmission pulley, whereby the gear housing and a first transmission pulley laterally overlap.
11. The transmission system of claim 10, wherein the portion of the first transmission pulley is of complementarily profile to the recess in order to permit the first transmission pulley to be at least partially disposed in the recess without preventing rotation of the first transmission pulley.
12. A movable closure incorporating the transmission system of any one of the preceding claims.
13. A belt transmission system for installation within a frame of a movable closure, the belt transmission system including a first pulley, a second pulley and a belt operatively engaged with the first and second pulleys, the first pulley having a first axis of rotation and the second pulley having a second axis of rotation, the first axis of rotation and the second axis of rotation being non-parallel to one another, wherein the shortest centre to centre distance between the first and second pulleys is less than about 5 times the diameter of the larger of the first and second pulleys or the diameter of the first or second pulley where the diameters are the same.
14. The belt transmission system of claim 13, wherein the belt transmission system includes a third pulley and a second belt operatively engaged with the second and third pulleys, the third pulley having a third axis of rotation that is non-parallel to the first axis of rotation and the second axis of rotation.
15. The belt transmission system of claim 14, wherein the first axis of rotation and the third axis of rotation are orthogonal to one another.
16. The belt transmission system of any one of claims 13 to 15, further including one or more guiding structures disposed between the first and second pulleys, wherein the one more guiding structures are configured to mitigate slippage of the belt from engagement with the first and second pulleys
17. A movable closure assembly, including a frame and a belt transmission system including a first pulley, a second pulley and a belt operatively engaged with the first and second pulleys, the first pulley having a first axis of rotation and the second pulley having a second axis of rotation, the first axis of rotation and the second axis of rotation being non-parallel to one another, wherein the belt transmission system is fully or substantially contained within the frame.
18. The movable closure assembly of claim 17, further including one or more guiding structures disposed between the first and second pulleys, wherein the one more guiding structures are configured to mitigate slippage of the belt from engagement with the first and second pulleys.
19. The movable closure of claim 17 or 18, wherein the belt transmission system includes a third pulley, and a second belt operatively engaged with the second and third pulleys, the third pulley having a third axis of rotation, the third axis of rotation being non-parallel to the first and second axis of rotation.
20. The movable closure of claim 19, wherein the first axis of rotation and third axis of rotation are substantially orthogonal to one another.