WO2017075669A1

WO2017075669A1 - Motorised wheel assembly for movable panel

Info

Publication number: WO2017075669A1
Application number: PCT/AU2016/051056
Authority: WO
Inventors: Hani Jaber; Simon JABER; David Garfield Blanch
Original assignee: Ciilock Engineering Pty Ltd
Priority date: 2015-11-06
Filing date: 2016-11-04
Publication date: 2017-05-11
Also published as: AU2016349953A1; CN108350713A; CN108350713B; AU2016349953B2

Abstract

A motorised wheel assembly (10, 10') for a movable panel includes a body or housing (12) for fixed connection to the panel and a motor (18, 18') having a motor body fixed relative to the body or housing (12). A driven wheel (14) is provided for engagement with a wheel path for movement of the panel along the wheel path. The driven wheel (14) is drivingly connected to the motor (18, 18'). A wheel adjustment assembly includes the driven wheel. The wheel adjustment assembly is such that the rotational axis (72) of the driven wheel (14) is movable relative to the body or housing (12) through an adjustment path such that throughout the adjustment path of the driven wheel (14), the driven wheel (14) maintains drive connection to the motor (18, 18').

Description

MOTORISED WHEEL ASSEMBLY FOR MOVABLE PANEL

Field of the invention

The present invention relates to a motorised wheel assembly for a movable panel. In particular, although not exclusively, the invention relates to a motorised carriage for a sliding door, such as a sliding glass door or other types of doors which are considerably heavy. The motorised wheel assembly also has application to sliding windows and other movable panels such as conference room dividers.

Background of the invention Motorised wheel assemblies for sliding doors are known. For example, US patent

8,800,206 discloses a motorised closure assembly having a motor which drives a track wheel (driven wheel) via a gearbox. The motor, gearbox and driven wheel are incorporated into a frame or housing which has a slanted posterior end. The frame is pivotable about a pivot point. The frame is adjusted to pivot about the pivot point by the levelling assembly which comprises a height adjustment wedge having a slanted anterior end. The height adjustment wedge is selectively movable by means of an adjustment screw and as it moves, the engagement between its slanted anterior end and the slanted posterior end of the frame causes the frame to pivot about the pivot point. Thus, it will be understood that to effect height adjustment of the driven wheel, the whole motor and gearbox will move also. This arrangement necessitates that the gears move up and down. Thus, it is not possible to use the maximum vertical space available to design the gearbox, because allowance must also be made for height adjustment of the gears. This unnecessarily limits the space available for the gearbox, placing unnecessary constraints on the design.

This particular design also suffers from the disadvantage that the posterior end of the frame projects rearwardly from the driven wheel which limits the adjustability before it fouls with the track. The greater the distance from the pivot point, the more readily the posterior end will touch the track. Additionally, this design provides for only one wheel and there is no provision for further rear wheels to divide the load. Distribution of weight is an important consideration where panels are heavy, as such panels with double or triple glazing.

It is therefore an object of the present invention to provide a motorised wheel assembly for a movable panel which overcomes or at least ameliorates one or more of the above mentioned disadvantages.

Another object of the present invention is to provide a motorised wheel assembly for a movable panel which provides a design choice over known motorised wheel assemblies. 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 ascertained, 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 accordance with the first aspect of the present invention, there is provided, a motorised wheel assembly for a movable panel, the motorised wheel assembly including: a body or housing for fixed connection to the panel; a motor having a motor body fixed relative to the body or housing; a driven wheel for engagement with a wheel path for movement of the panel along the wheel path, the driven wheel being drivingly connected to the motor; a wheel adjustment assembly including the driven wheel, the wheel adjustment assembly being such that the rotational axis of the driven wheel is movable relative to the body or housing through an adjustment path such that throughout the adjustment path of the driven wheel, the driven wheel maintains drive connection to the motor.

Preferably, a drive mechanism driven by the motor provides the drive connection between the motor and the driven wheel. Preferably, a portion of the drive mechanism is movable relative to the housing and a remainder of the drive mechanism is fixed relative to the housing such that, throughout the adjustment path of the driven wheel, the driven wheel maintains drive connection with the drive mechanism. The movable portion of the drive mechanism may be integrated with the driven wheel. For example, the driven wheel may include a wheel hub portion which is integrally formed with a final gear portion of the drive mechanism. In alternative forms of the invention, the driven wheel and the movable portion of the drive mechanism may be discrete members.

The wheel adjustment assembly may further include at least one other wheel which may be driven or passive i.e. not driven but free to rotate and engage with the wheel path. Where there are two or more other wheels, some may be driven and some may be passive. Likewise, the rotational axis of the at least one other wheel is preferably also adjustable.

A gear train is one preferred type of drive mechanism. Preferably, the drive mechanism is substantially fixed. For instance, the gear train might include a series of gears including a penultimate rotatable drive component i.e. a penultimate gear and a final gear portion. Preferably, the gears all have substantially stationary axes of rotation relative to the housing, except for the final gear portion whose position is adjustable.

However, chain and belt drives are also within the scope of the present invention. For example, a chain may connect two sprocket wheels i.e. a penultimate sprocket wheel and a final sprocket wheel portion provided on the driven wheel. The final sprocket wheel portion and the associated chain/belt may be adjustable.

Maintaining the driven wheel in drive connection with the drive mechanism is preferably achieved by constraining axial movement of the driven wheel relative to the housing to a constant spacing from the axis of the penultimate rotatable drive component. The movement of the driven wheel may be constrained by a link. Preferably, the link has a first axis aligned with the rotational axis of the driven wheel and a second pivot axis fixed relative to the housing, the second pivot axis being aligned with the axis of the penultimate rotatable drive component.

For example, consider the example of the gear train. The link enables the driven wheel to pivot relative to the housing about a fixed pivot axis aligned with the axis of the penultimate gear. This maintains the final gear portion in engagement with the penultimate gear while allowing movement of the driven wheel as required for axial adjustment.

In the preferred configuration with one or more passive wheels, suitably all the wheels are movable relative to the housing for adjustment purposes.

The wheel(s) may be selectively movable for height adjustment purposes. In other words, the user or the installer may decide that the panel requires height adjustment relative to the wheel path for improved operation of the movable panel.

As an addition to the selective height adjustment function, or as an alternative thereto, it is possible that all the wheels may be movable relative to each other, as well as relative to the housing. This provides a self-levelling function which enables the forces to be balanced between all the wheels of the wheel adjustment assembly. The degree of self-levelling may be determined by the characteristics of the wheel path. For example, there may be misalignment of the wheel path relative to the panel, such as an inclined track relative to a geometrically square panel. In this case, one wheel may position itself lower than the other relative to the housing. Alternatively, the wheel path may contain undulations or bumps. In this case, one or more wheels may temporarily move relative to the housing to accommodate the undulations or bumps. The self- levelling function is such that the wheels position themselves in order to maintain each wheel in contact with the wheel path with the force substantially balanced between all the wheels.

For further understanding of the selective height adjustment feature and the self- levelling feature, reference is made to our earlier international patent applications WO201 1/100788 and WO 2015/017878, the disclosures of which are incorporated herein by reference.

To effect relative and/or selective movement of the wheels of the wheel adjustment assembly, each of the wheels may be carried by a wheel carrier which is slidable along an inclined slide path. The wheel carriers are confined between end constraints which are non-height adjustable. The weight of the panel will force the wheel carriers into the highest possible position on the slide paths as determined by the spacing of the end constraints. Thus, selective adjustment of the spacing between the end constraints will reposition the wheel carriers along their respective inclined slide paths, thus adjusting the height position of the wheels relative to the housing.

According to the self-levelling feature, the wheel carriers self-move along their respective slide paths to accommodate track variations from the ideal. Where the end constraints are static, movement of one wheel will cause countermovement of the other wheel(s) to the extent permitted by the end constraints and any other in-built constraints.

At least some of the slide paths may be defined on one or more separating members, each provided between adjacent wheel carriers. For example, a separating member may define two slide paths converging downwardly, one slide path per wheel carrier. Each separating member may be passively movable in a longitudinal direction substantially parallel to the wheel path, according to the position of the wheel carriers along the slide paths on each side. Movement of each separating member may be constrained in the longitudinal direction.

In a first preferred embodiment of the invention, a separating member is disposed between the driven wheel carrier and the passive wheel carrier, the separating member providing respective slide paths for the driven wheel carrier and the passive wheel carrier. The separating member may be in the form of a wedge member providing inclined slide paths which converge downwardly.

The passive wheel carrier may be mounted to a movable constraint device for effecting the selective height adjustment. The movable constraint device may be selectively adjustable to slide in the longtitudinal direction substantially parallel to the wheel path. Preferably, a second link is provided to link the passive wheel or the passive wheel carrier to the movable constraint device. Preferably, the second link has a first pivot axis aligned with the rotational axis of the passive wheel and a second pivot axis which provides for pivotal movement of the second link relative to the movable constraint device.

In a second embodiment of the invention there may be a driven wheel, a driven wheel carrier, a first passive wheel, a first passive wheel carrier, a second passive wheel, and a second passive wheel carrier. In this form of the invention, the movable constraint device may provide an inclined slide path for the second passive wheel carrier. The two passive wheel carriers may be slidable relative to one another in a direction substantially perpendicular to the wheel path. The present invention may be applicable to a large range of situations. For example, the motorised wheel assembly may be fitted into a panel. For example the motorised wheel assembly may be fitted into the bottom of the panel or the top of the panel. The orientation of the motorised wheel assembly may be inverted to fit into the top of the panel compared to its orientation in the bottom of the panel. References herein to up/down are references to the assembly's orientation for the bottom of the panel.

In panels for sliding glass doors or windows, the panel may have a frame with a top rail and a bottom rail. The motorised wheel assembly may be fitted into the bottom rail or the top rail. As will be appreciated, internal cross-sectional area of the bottom and top rails constrains the size of the motorised wheel assembly. In this form of the invention, where the motorised wheel assembly is mounted to or within a panel, the motorised wheel assembly will be in the form of a "carriage" for carrying the panel.

It is also envisaged that the motorised wheel assembly could be mounted in the side of a panel, for example in the side rail or alternatively in the door or window jamb to operate on the panel. In this orientation, it will be understood that "height adjustment" means the adjustment of the wheel(s) relative to the housing in a direction transverse to the wheel path.

It is also envisaged that the motorised wheel assembly may be positioned adjacent the panel so that the driven wheel engages with the movable panel. Thus, an edge of the panel such as the bottom, top or side edge might define the wheel path for the driven wheel. In this form of the invention, the motorised wheel assembly could be mounted within the door or window frame.

The wheels may be in the typical form of a cylinder or annulus, typically made of plastic. The wheel path may be in the form of a track. However, a track is not essential and the wheel(s) could operate directly upon the floor surface or grooves within the floor surface, rather than a dedicated or discrete track.

However, in an alternative form, the driven wheel may be in a form of a pinion which is engageable with a rack. This might have application where the motorised wheel assembly is top or side mounted relative to the panel to obtain additional traction.

The drive mechanism may be of any form and will be dependent somewhat upon the constraints of the housing as dictated by other constraints such as the internal space of the top or bottom rail of a door panel. For example, such a constraint may dictate that the motor has its output shaft substantially parallel to the wheel path. Thus, the drive train may be required to convert this rotary motion to rotary motion in a transverse axis parallel to the axis of the driven wheel. Typically, the drive mechanism will also change the speed ratio of the motor output relative to the output of the drive mechanism. This will typically be a reduction drive mechanism.

In accordance with a second aspect of the present invention, there is provided, a motorised wheel assembly for a movable panel, the motorised wheel assembly including: a motor; a driven wheel for engagement with a wheel path for movement of the panel along the wheel path, the driven wheel being drivingly connected to the motor; a wheel adjustment assembly, the wheel adjustment assembly including the driven wheel and at least one other wheel, each having a rotational axis, wherein the wheel adjustment assembly is such that the rotational axes of the driven wheel and the at least one other wheel are movable relative to the motor, such movement of the driven wheel and the at least one other wheel being interrelated.

Any of the preferred features described above in connection with the first aspect of the invention may have application to the second aspect of the invention. 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.

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

In order that the invention may be more fully understood, some embodiments will now be described by way of example, with reference to the figures in which:

Figure 1 is an exploded perspective view of the motorised wheel assembly in accordance with a first preferred embodiment of the present invention;

Figure 2 is a side view of the motorised wheel assembly as shown in

Figure 1 ;

Figure 3 is a side view, similar to Figure 2, except with the housing removed for clarity, the wheel assembly being shown in the lowest adjustment position; · Figure 4 is a view similar to Figure 3, except with the wheel assembly shown in the highest adjustment position;

Figure 5 is a view similar to Figure 3, except showing the self-levelling feature as the wheel assembly encounters an undulation in the track;

Figure 6 is a side view of a sub-assembly from Figure 1 illustrating the driven wheel, the driven wheel carrier and the penultimate gear;

Figure 7 is a plan view of the sub-assembly of Figure 6;

Figure 8 is a cross-sectional view through A-A of Figure 6;

Figures 9 and 10 are perspective views of the sub-assembly of Figure 6;

Figure 1 1 is a perspective view of the sub-assembly of Figure 6 with the driven wheel carrier removed for clarity; Figure 12 is a side view of a second preferred embodiment of the present invention;

Figure 13 is a side view similar to Figure 12, except with the housing removed for clarity, the wheel assembly being shown in the lowest adjustment position; · Figure 14 is a view similar to Figure 13, except showing the wheel assembly in the highest adjustment position;

Figure 15 is a side view similar to Figure 14, except showing the self- levelling feature as the wheel assembly encounters an undulation in the track;

Figure 16 is an exploded perspective view of an alternative gear train of the present invention;

Figure 17 is an assembled view of the gear train of Figure 16; and

Figure 18 is a view similar to Figure 16, except with the housing shown.

Detailed description of the embodiments

Referring to Figure 1 , it will be appreciated that the motorised wheel assembly 10 incorporates similar features to that disclosed in the applicant's earlier international patent specifications WO201 1/100788 and WO2015/017878. The disclosures of these earlier specifications are hereby incorporated herein by reference.

The first embodiment of the motorised wheel assembly 10 will be explained in the context of a housing 1 1 (Fig. 2) intended to be fitted into the bottom rail of a sliding door panel (not shown). Thus the wheels 14, 16 will engage with a track (not shown) underneath the sliding door. However this is only one of a large number of possible implementations and the invention should not be limited to the present context in which it is described.

Referring to Figure 1 , the motorised wheel assembly 10 includes a motor 18 which drives a drive mechanism in the form of gear train 20 which in turn drives a driven wheel 14 which engages with the wheel path, which in most cases is a track underlying the door panel. The driven wheel 14 is carried by a wheel carrier 24. A passive wheel 16 is also provided to help distribute the weight of the door panel. The passive wheel 16 is housed in the passive wheel carrier 26.

The position of the wheel axes of the wheels 14, 16 are adjustable relative to the housing 1 1 . This provides for selective height adjustment, self-levelling and load sharing as will be explained. The wheel carriers 24, 26 co-operate with the separation member 28 and the slidable end constraint 30 to allow for selective height adjustment and self- levelling.

As will be understood from Figures 1 and 2, the motor 18 has a cylindrical body and is mounted to an end plate 32 provided at the end of housing 1 1 . The shaft 19 of the motor 18 projects through an aperture 34 provided in the end plate 32 for engagement with the gear train 20. It would be appreciated that the motor 18 produces rotational motion about the axis of shaft 19 and this axis is substantially parallel to the wheel path traversed by wheels 14, 16. Thus, one of the functions of the gear train 20 is to convert the rotational motion about the axis of shaft 19 to rotational motion in a direction substantially perpendicular, in order to drive driven wheel 14. Secondly, the function of the gear box 20 is to bring about a reduction in speed for the output of the gear train 20. The principles of gearbox design are well known by those skilled in the field of gearbox design and need not be explained further here.

Gear 36 is regarded as the penultimate gear of the gear train 20 and the gear portion 38 incorporated into driven wheel 14 is regarded as the final gear portion of the gear train 20. The penultimate gear 36 meshes with the final gear portion 38 to drive driven wheel 14.

The gear train 20, save for the final gear portion 38 is housed within the main part of the housing 12 and a cover plate 22 extends over the gear train 20 and encloses this part of the housing. From the viewpoint of Figure 1 , the closest end of the main housing part 12 and the corresponding end of cover plate 22 each include 2 apertures 40 for receipt of fasteners 42 to mount the end plate 32 at the end of the housing 1 1 . The cover plate 22 is also secured to the main part of the housing 12 by means of fasteners 44 which extend through apertures in the cover plate 22 and are received in threaded bores 46 in the main part of the housing 12. As will be appreciated from a study of Figure 1 , the main part of the housing 12 is shaped to conform to the shape of the gear train 20. The inside of the cover plate 22 is also shaped for this purpose. When the cover plate 22 is assembled with the main part of the housing 12, the 2 parts form an enclosure for receipt of the gear train 20 and this enclosure can be provided with a suitable lubricant.

The main part of the housing 12 and the cover plate 22 are also provided with 4 blind bores 48, 50. These blind bores are open to the enclosed space and receive the spigots 52, 54 of the gear train 20 and associated bearings. Thus, the rotational axes of the gears of the gear train 20, except for the final gear portion 38, are fixed relative to the housing 1 1 . The gear train 20, with the exception of final gear portion 38 can thus be designed to utilise the maximum possible height of the housing 1 1 , given that these gears do not need to translate relative to the housing 1 1. It will also be understood that the housing 1 1 is fixed relative to the door panel and by virtue of this fact, the gear train 20 (with the exception of the final gear portion 38) and the motor 18 do not move relative to the door panel.

In contrast, the driven wheel 14 and the passive wheel 16 are movable relative to the housing 1 1 and provide for selective height adjustment and self-levelling and load sharing as will be explained.

Figures 6 - 1 1 illustrate the meshing of penultimate gear 36 with the final gear portion 38 in order to drive the driven wheel 14. As can be seen from Figure 8, the driven wheel 14 includes a wheel hub portion 60 upon which the wheel tread 62 is fitted. The wheel tread 62 is suitably a softer plastic material than the wheel hub portion 60. The wheel tread 62 has an annular recess 64 of concave cross section to cooperate with a track having a convex profile. The wheel hub portion 60 is integrally formed with the final gear portion 38. The wheel hub portion 60 includes a recess 66 for receipt of wheel bearing 68 enabling the wheel hub portion 60 to rotate freely upon the axle 70. The axis 72 of the wheel axle 70 defines the axis of rotation of wheel 14. When the penultimate gear 36 drives the final gear portion 38, the wheel 14 will turn on axle 70 so that the driven wheel 14 will be driven along the track, carrying the motorised wheel assembly 10 and the door panel along the track. As mentioned, the axis 72 of the wheel 14 is adjustable relative to the housing 1 1 to enable selective height adjustment and self-levelling. However, the final gear portion 38 must remain in meshing engagement with the penultimate gear 36 throughout the wheel's range of motion. In order to achieve this, a first pair of links 74 is provided as most clearly shown in Figure 1 1 . The links 74 link the driven wheel 14 to rotate about the rotational axis 76 of the penultimate gear 36. Links 74 are provided on both sides of the penultimate gear 36 and the driven wheel 14. As already mentioned, the spigots 54 of penultimate gear 36 are journaled in blind bores 50 of the housing 1 1 so the axis 76 of spigot 54 is fixed relative to the housing 1 1 and the door panel. Thus, the axis 72 of the driven wheel 14 can move in a circular arc about the axis 76. The end of each link 74 adjacent the driven wheel 14 has an aperture 78 and a concentric annular boss 80. The ends of the wheel axle 70 are received in aligned apertures 78 of the links 74. The outer periphery of the bosses 80 are received in aligned apertures 83 (see Figure 1 ) in the carrier 24. This enables rotation between the carrier 24 and the links 74 because although the links 74 traverse in a circular arc, the carrier 24, while it will follow the circular movement, should maintain its orientation for engagement with the separation member 28 as will be explained.

In a similar fashion, the other end of the links 74 each include a central aperture 82 and concentric boss 84. The gear spigot 54 and associated bearings are received in the aligned apertures 82. The bosses 84 are received within shaped recesses 85 provided in the housing 12 and cover plate 22. Sector-shaped recesses 87 in the housing 12 and the cover plate 22 allow for rotation of the links 74 and define the limits of travel for the links 74.

The height adjustment feature and the self-levelling feature will now be described with reference to Figure 1 . The separation member 28 which separates the driven wheel carrier 24 from the passive wheel carrier 26 is in the form of a height adjustment wedge 28 which defines 2 slide paths 90 which converge downwardly. The height adjustment wedge 28 has tabs 92 protecting from each side (only one is shown) for engagement in respective horizontal slots 94 provided in the side walls of the main part of the housing 12. This constrains the height adjustment wedge 28 for horizontal movement only within the limits determined by the horizontal slot 94. The slide paths 90 each have constant cross-sections comprised of a narrow neck carrying a bulbous end portion. Both of the carriers 24, 26 engage with respective slide paths 90 and for this reason have complementary shaped recesses of constant cross section comprising a bulbous cavity opening outwardly via a narrow throat. This enables the wheel carriers 24, 26 to slide along the respective slide paths 90 as can be seen in Figures 3 and 4. Figure 3 illustrates the lowest adjustment position in which the wheel carriers 24, 26 are in their highest position relative to the wedge 28 and housing 1 1 , constituting the most compact form of the assembly 10. Thus, the housing 1 1 and likewise the door panel will be in the lowest position relative to the track.

In Figure 4, the wheel assembly is shown in its highest adjustment position where the wheel carriers 24, 26 have slid the full extent of the slide paths 90 to the lowermost position relative to wedge 28, consequently moving the housing 1 1 and the door panel to its highest possible adjustment position.

Selective height adjustment is achieved by adjustment of the slidable end constraint 30 as shown in Figure 1 . The slidable end constraint 30 is provided with tabs 96 which are received within respective slots 98 on each side of the housing 12. This constrains the slidable end constraint 30 for sliding movement in the longitudinal direction of the housing 1 1 as determined by the constraints of the slots 98.

The slidable end constraint 30 is provided with a recess 100 on its outer end for receipt of an internally threaded nut 102. The shape of the recess 100 is commensurate with the shape of the nut 102 so the nut is constrained from rotating. An adjusting screw 104 is externally threaded to engage with threaded nut 102. The adjusting screw 104 is constrained from translating along its longitudinal axis and is merely permitted to rotate because the screw head 106 is captured within housing 1 1 , in part by pins 108 which traverse between the side walls of the main part of the housing 12 between aligned apertures 109. For further detail see our earlier international applications WO201 1/100788 and WO2015/017878. Rotation of the adjusting screw 104 will cause the slidable end constraint 30 to slide within the main part of the housing 12, depending upon the direction of rotation of the adjusting screw 104.

With continued reference to Figure 1 , passive wheel 16 is journaled for rotation about passive wheel axle 1 10. The passive wheel 16 and the passive wheel carrier 26 are connected to the end constraint 30 by means of a second pair of links 1 12. The second pair of links 1 12 have a similar configuration to the first pair of links 74. The axle 1 10 is received in aligned apertures 1 14. The bosses 1 16 are received within open sockets 1 18 provided in the opposite side walls of the passive wheel carrier 26.

The end constraint 30 is provided with an aperture 1 19 to receive stub 120 which defines an axis of rotation 122 for the links 1 12. The stub 120 is received in the aligned apertures 124. Thus, the passive wheel 16 is permitted to move in a circular arc about axis 122, enabling the wheel axis to adopt a range of positions along a circular arc. The passive wheel carrier 26 also moves with the links 1 12 but since the passive wheel carrier 26 is rotatable relative to the links 1 12, it can maintain its orientation relative to the housing 1 1 and maintain co-operative orientation relative to its slide path 90.

The method to perform selective height adjustment will now be explained with reference to Figures 1 , 3 and 4. As already explained, links 74 are rotatable about axis 76 which is fixed relative to the housing. On the other hand, the position of axis 122 is movable in a horizontal direction as the end constraint 30 is moved by adjusting screw 104. The wedge 28 is only movable in horizontal direction relative to the housing 1 1 . Thus, when the distance between axes 76 and 122 is reduced, the links 74 and 1 12 rotate about their respective axes to move the wheels 14, 16 to a lower position as the carriers 24, 26 slide along the slide paths 90. The lowermost position of the wheels 14, 16 is shown in Figure 4. The wedge 28 has slid to the left in the process as can be seen from a comparison of Figures 3 and 4. In this position, the wheels, 14, 16 are in their lowermost position relative to the housing 1 1 which represents the uppermost position of the door panel. Reversing the direction of the adjusting screw 104 permits adjustment in the opposite direction back to the position of Figure 3. Thus, it will be understood that the provision of link 74 enables adjustment of the driven wheel 14 while maintaining the penultimate gear 36 in contact with the final gear portion 38 so that the driven wheel 14 may be driven in all positions of its circular arc of travel. Link 1 12 prevents the wheel 16 from falling out of the housing 1 1 .

Figure 5 illustrates the self-levelling feature of the present invention. As the wheel 16 encounters undulations in the track such as depression 130, the wheel 16 maintains contact with the track. Since the spacing between axes 122 and 76 remains constant, the wedge, 28 and the driven wheel carrier 24 adjust their positions to accommodate the downward movement of passive wheel 16 relative to the housing. In this manner, the wheels 16, 14 maintain contact with the track, thus sharing the load.

The self-levelling feature also has application where the track is inclined relative to a door panel which is geometrically square. One of the wheels will therefore adopt a lower position relative to the housing to maintain the door panel in a level orientation during travel along the inclined track. Both wheels remain in contact with the track, thus sharing the load.

Figures 12-15 illustrate an alternative embodiment which has 3 wheels 14, 16 and second passive wheel 140. The motorised wheel assembly 10' is similar in many respects to the motorised wheel assembly 10 of the first embodiment. Like numerals represent like parts. Parts which have been modified or adapted for the second embodiment are indicated by prime symbol (').

Like the previous embodiment, the first passive wheel 16 is housed in a first passive wheel carrier 26'. However the first passive wheel carrier 26 is not linked to the end constraint 30'.

The second passive wheel 140 is carried by a second passive wheel carrier 142. The second passive wheel carrier 142 is slidable relative to a slide path 144 provided on the inner end of the end constraint 30'. The slide path 144 and the co-operating part of the wheel carrier 142 are the same or similar as the slide paths 90. Additionally, the 2 passive wheel carriers 26' and 142 have cooperable slide surfaces shaped in a similar fashion, except that the slide surfaces 146 are not inclined but are arranged substantially vertically relative to the longitudinal direction of the housing 1 1 . The wheel carriers 26' and 142 are constrained in their relative vertical movement by the presence of a projection provided on wheel carrier 26' received within a slot on wheel carrier 146 to define the limits of relative vertical movement.

Figure 13 illustrates the lowermost position of the housing and door relative to the track. Figure 14 illustrates the height adjustment effected by inward movement of the end constraint 30' which causes the wheel carriers 24, 26' and 142 to adopt their lowermost position on their respective slide paths 90, 144. Figure 15 illustrates the self-levelling function of the wheel assembly 10' when undulations in the track are encountered.

Figures 16 to 18 illustrate a further alternative embodiment having a gear train 20'. Unlike the gear train 20 of Figures 1 to 15, the gear train 20' utilises a worm drive 150 comprising a worm 152 and a worm gear 154. Similar to gear train 20 of Figures 1 to 15, the gear train 20' is configured to convert the rotational motion about the axis of shaft 19' of motor 18' to rotational motion in a direction substantially perpendicular. Additionally, the gear train 20' is also configured to bring about a reduction in speed for the output of the gear train 20'. As will be appreciated by those skilled in the art of gear train design, the gear train 20' may provide a greater gear ratio reduction as compared to the gear train 20 of Figures 1 to 15.

The gear train 20' is smaller in overall dimension, particularly lengthwise along the longitudinal axis of the housing 12', as compared to the gear train 20 of Figures 1 to 15. Advantageously, this allows for a longer, more powerful, motor 18' to be utilised with the illustrated wheel assembly.

The foregoing describes only some embodiments of the present invention and modifications may be made thereto without departing from the scope of the invention.

Claims

1 . A motorised wheel assembly for a movable panel, the motorised wheel assembly including: a body or housing for fixed connection to the panel; a motor having a motor body fixed relative to the body or housing; a driven wheel for engagement with a wheel path for movement of the panel along the wheel path, the driven wheel being drivingly connected to the motor; a wheel adjustment assembly including the driven wheel, the wheel adjustment assembly being such that the rotational axis of the driven wheel is movable relative to the body or housing through an adjustment path such that throughout the adjustment path of the driven wheel, the driven wheel maintains drive connection to the motor.

2. The motorised wheel assembly of claim 1 , further including a drive mechanism driven by the motor, said drive mechanism providing the drive connection between the motor and the driven wheel.

3. The motorised wheel assembly of claim 2, wherein a first portion of the drive mechanism is fixed relative to the body or housing and a second portion of the drive mechanism is movable relative to the body or housing such that, throughout the adjustment path of the driven wheel, the driven wheel maintains drive connection with the drive mechanism.

4. The motorised wheel assembly of claim 3, wherein the drive mechanism is a gear train.

5. The motorised wheel assembly of claim 4, wherein the first portion of the drive mechanism includes a penultimate gear of the gear train, and the second portion of the drive mechanism is a final gear portion of the gear train, the final gear portion being associated with the driven wheel and being driveable by the penultimate gear.

6. The motorised wheel assembly of claim 5, wherein the final gear portion forms part of a wheel hub of the driven wheel.

7. The motorised wheel assembly of claim 5 or 6, wherein the first portion of the drive mechanism includes one or more other gears associated with the penultimate gear, the one or more other gears and the penultimate gear having substantially stationary axes of rotation relative to the body or housing.

8. The motorised wheel assembly of any one of claims 5 to 7, wherein the driven wheel maintains drive connection to the drive mechanism by one or more links associated with the penultimate gear and the final gear portion, the one or more links constraining axial movement of the driven wheel relative to the body or housing to a constant spacing from an axis of rotation of the penultimate gear.

9. The motorised wheel assembly of claim 8, wherein the one or more links have a first axis aligned with the rotational axis of the driven wheel and a second, pivot, axis fixed relative to the body or housing, the second axis being aligned with the axis of rotation of the penultimate gear.

10. The motorised wheel assembly of any one of claims 1 to 9, wherein the wheel adjustment assembly includes at least one other wheel for engagement with the wheel path.

1 1 . The motorised wheel assembly of claim 10, wherein the rotational axis of the at least one other wheel is adjustable relative to the body or housing.

12. The motorised wheel assembly of claim 1 1 , wherein the driven wheel and the at least one other wheel of the wheel adjustment assembly are carried by respective wheel carriers that are slidable along respective inclined slide paths.

13. The motorised wheel assembly of claim 12, wherein the body or housing includes an end constraint that is selectively adjustable to reposition the wheel carriers along their respective inclined slide paths to adjust a spacing between the wheel carriers and thereby a height position of the wheels relative to the body or housing.

14. The motorised wheel assembly of claim 12 or 13, wherein the inclined slide paths are defined on a separating member provided between the wheel carriers of the driven wheel and the at least one other wheel.

15. The motorised wheel assembly of claim 14, wherein the separating member is movable passively in the longitudinal direction substantially parallel to the wheel path, according to the position of the wheel carriers relative to each other.

16. The motorised wheel assembly of any one of claims 13 to 15, wherein the wheel carrier of the at least one other wheel is associated with the selectively adjustable end constraint by one or more additional links.

17. The motorised wheel assembly of claim 16, wherein the one or more additional links have a first pivot axis aligned with the rotational axis of the at least one other wheel and a second pivot axis for providing pivotal movement of the one or more additional links relative to the selectively adjustable end constraint.

18. The motorised wheel assembly of any one of claims 10 to 17, wherein the at least one other wheel is either a driven wheel or a non-driven, passive, wheel.

19. A motorised wheel assembly for a movable panel, the motorised wheel assembly including: a motor; a driven wheel for engagement with a wheel path for movement of the panel along the wheel path, the driven wheel being drivingly connected to the motor; a wheel adjustment assembly, the wheel adjustment assembly including the driven wheel and at least one other wheel, each having a rotational axis, wherein the wheel adjustment assembly is such that the rotational axes of the driven wheel and the at least one other wheel are movable relative to the motor, such movement of the driven wheel and the at least one other wheel being interrelated.

20. The motorised wheel assembly of claim 19, wherein the driven wheel and the at least one other wheel are carried by respective wheel carriers.

21 . The motorised wheel assembly of claim 20, wherein the movement of the driven wheel and the at least one other wheel are interrelated by the respective wheel carriers being slidable along respective inclined slide paths defined on a separating member provided between the wheel carriers.

22. The motorised wheel assembly of claim 21 , wherein the separating member is movable passively in a longitudinal direction substantially parallel to the wheel path, according to the position of the wheel carriers relative to each other.

23. The motorised wheel assembly of claim 21 or 22, wherein the respective wheel carriers are slidable along their respective inclined slide paths such that the rotational axes of the driven wheel and the at least one other wheel are movable relative to the motor whereby the driven wheel and the at least one other wheel maintain contact with the wheel path.

24. The motorised wheel assembly of claim 22 or 23, further including an end constraint that is selectively adjustable to reposition the wheel carriers along their respective inclined slide paths to adjust a spacing between the wheel carriers and thereby a height position of the wheels relative to the motor.

25. The motorised wheel assembly of any one of claims 19 to 24, wherein the at least one other wheel is either another driven wheel or a non-driven, passive, wheel.

26. The motorised wheel assembly of any one of claims 19 to 25, wherein the driven wheel is drivingly connected to the motor by a drive mechanism.

27. The motorised wheel assembly of claim 26, wherein a first portion of the drive mechanism is fixed relative to the motor and a second portion of the drive mechanism is movable relative to the motor such that, throughout an adjustment path of the driven wheel, the driven wheel maintains drive connection with the drive mechanism.

28. The motorised wheel assembly of claim 27, wherein the drive mechanism is a gear train.

29. The motorised wheel assembly of claim 28, wherein the first portion of the drive mechanism includes a penultimate gear of the gear train, and the second portion of the drive mechanism is a final gear portion of the gear train, the final gear portion being associated with the driven wheel and being driveable by the penultimate gear.

30. The motorised wheel assembly of claim 29, wherein the final gear portion forms part of a wheel hub of the driven wheel.

31 . The motorised wheel assembly of claim 30, wherein the driven wheel maintains drive connection to the drive mechanism by one or more links associated with the penultimate gear and the final gear portion, the one or more links constraining axial movement of the driven wheel relative to the motor to a constant spacing from an axis of rotation of the penultimate gear.

32. The motorised wheel assembly of claim 31 , wherein the one or more links have a first axis aligned with the rotational axis of the driven wheel and a second, pivot, axis fixed relative to the motor, the second axis being aligned with an axis of rotation of the penultimate gear.

33. The motorised wheel assembly of claim 31 or 32, wherein the wheel carrier of the at least one other wheel is associated with the selectively adjustable end constraint by one or more additional links.

34. The motorised wheel assembly of claim 33, wherein the one or more additional links have a first pivot axis aligned with the rotational axis of the at least one other wheel and a second pivot axis for providing pivotal movement of the one or more additional links relative to the selectively adjustable end constraint.

35. The motorised wheel assembly of any one of claims 19 to 34, wherein the motor has a motor body fixed relative to a body or housing of the motorised wheel assembly.

36. The motorised wheel assembly of claim 12 or claim 20 wherein there are two of the at least one other wheels, the two other wheels being carried by respective wheel carriers which have cooperable upright slide surfaces and are constrained in vertical movement relative to each other.