WO2010114480A1

WO2010114480A1 - Door assembly

Info

Publication number: WO2010114480A1
Application number: PCT/SG2009/000115
Authority: WO
Inventors: Eko Heri Supriadi; Yukiharu Wakiguchi; Takeshi Nakamura; Pin Benny Lim
Original assignee: Panasonic Avc Networks Singapore Pte. Ltd.
Priority date: 2009-03-31
Filing date: 2009-03-31
Publication date: 2010-10-07
Also published as: WO2010114480A8

Abstract

A door assembly (102) particularly but not exclusively, for audio and/or video equipment is disclosed. In a described embodiment, the assembly comprises a door (103) and a housing (104) having mounted thereto a driven wheel (120). The door (103) is slidably mounted to the housing (104). A first track (110) and a second track (112) are provided for the door to slide to different open positions. A third track (118) is also provided and is movable by the driven wheel (120) between a first position to enable the driven wheel (120) to engage with the first track (110) and a second position to enable the driven wheel (120) to engage with the second track (112).

Description

Door Assembly

Field of the Invention

The present invention relates to a door assembly. More particularly, but not exclusively, the present invention relates to a sliding door assembly for audio and/or video equipment.

Background of the Invention

Door assemblies are commonly arranged over one or more openings to act as movable partitions between the interior of an enclosed space and the external environment. In audio and/or visual equipment, for example, a door assembly is typically arranged on the top surface or the front surface of the equipment to allow access into the interior of the equipment housing, and, in particular, into interior spaces that are arranged to receive audio and/or visual media such as compact discs.

Conventional door assemblies for audio and/or visual equipment comprise pivoting doors that are either motorized or spring-biased for movement between an open position and a closed position. One disadvantage in providing pivoting doors is that the door when opened provides only a relatively limited access to the opening.

There are also known door assemblies that utilize a sliding mechanism to slide the door between open and closed positions. While these assemblies overcome the restricted access, drawback of pivoting mechanisms, complexity and stability problems arise if the door is arranged to slide to more than one open position. Complex software feedback control systems are typically relied upon to determine the position of the door, especially to determine when the door has returned to a closed position from the open positions. There are also calibration issues that arise over time and that lead to poor door stability with respect to the closed position. As a consequence, the door may be misaligned when closed, resulting in an undesirable degradation in the ability of the door to isolate the enclosed space from the external environment. Summary of the Invention

In a specific expression of the invention, there is provided a door assembly comprising: a housing having rotatably mounted thereto a driven wheel, and a door slidably mounted to the housing, the door having a first track configured to engage the driven wheel to slide the door to a first open position, a second track configured to engage the driven wheel to allow the door to slide to a second open position, and a third track being movable by the driven wheel between a first position to enable the driven wheel to engage with the first track and a second position to enable the driven wheel to engage with the second track.

Preferably the first track is a first toothed rack, the second track is a second toothed rack, the third track is a cam gear, and the driven wheel is a driven gear. As used herein, the term 'cam gear' denotes a component having teeth configured to mesh with the driven gear and to move between the first position and the second position under rotation of the driven gear. Non-limiting examples of a cam gear include a toothed wheel or part of a toothed wheel.

Preferably the first and second toothed racks are fixed to the door and are separated by a recess in which the cam gear is positioned.

Preferably the cam gear includes a projection configured to be received in a groove provided in the recess.

Preferably one or more projections are provided in the groove, the one or more projections being configured to secure the cam gear in the first position or the second position.

Preferably the door includes a pivot structure, the cam gear being pivotable between the first position and the second position about the pivot structure.

Preferably the cam gear is configured to pivot by about 90° to move between the first position and the second position. Preferably the cam gear is further pivotable to a third position between the first position and the second position, the third position being such that the first end of the cam gear is misaligned with the first toothed rack and the second end of the cam gear is misaligned with the second toothed rack.

Preferably the cam gear includes teeth arranged in an arcuate path. Preferably the cam gear has a substantially quadrant shape, and wherein the arcuate path is along an arc of the quadrant.

Preferably the housing includes a planar surface parallel to the door, and wherein the driven gear is rotatably mounted on the planar surface. Preferably the planar surface has an edge having a length, the driven gear being rotatably mounted adjacent the edge and substantially in the centre of the length.

Preferably the first and second toothed racks are provided adjacent an edge of the door.

Preferably the door assembly forms part of an audio and/or visual equipment, and wherein the housing includes an opening configured to receive one or more audio and/or video media.

As will be apparent from the following description, the specific expression of the present invention provides a simple yet robust mechanically-controlled mechanism that stabilizes the home position of a door movable to two open positions, and that additionally is able to lock the door in the home position.

Brief Description of the Drawings

A preferred embodiment of the door assembly will now be described by way of example with reference to the accompanying drawings of which: Figure 1 A shows a front perspective view of an audio-visual equipment with the door of the door assembly being closed, Figure 1 B shows a front perspective view of the audio-visual equipment of Figure 1A with the door being partially opened, and Figure 1C shows a back perspective view of the door assembly,

Figures 2A and 2B respectively show a plan view and perspective view of the door base,

Figures 3A to 3D respectively show a plan view, bottom view, bottom perspective view and top perspective view of the cam gear,

Figures 4A and 4B respectively show a plan view and perspective view of the door base unit comprising the cam gear attached to the door base, Figures 5A and 5B respectively show a plan view and perspective view of the housing of the door assembly,

Figures 6A to 6C show the operation of the door assembly when opening to the second open position,

Figures 7A to 7C show the operation of the door assembly when opening to the first open position, and

Figures 8A to 8D show the use of grooves and protrusions in the door base to position the cam gear,

Figure 9 shows the area of the tip of the cam gear that is flexible, Figures 10A to 10C show one locking feature of the door assembly, and Figure 11 shows another locking feature of the door assembly.

Detailed Description of the Preferred Embodiment

Figure 1A shows an audio-visual equipment 100 from a front perspective view. The audio-visual equipment 100 has a door assembly comprising a door 103 on a housing 104, with the housing 104 including two openings or compartments C1 , C2 hidden behind the door 103. Upon sliding of the door 103, access to the compartments is made possible. Figure 1B shows the door 103 in the process of being slid open to permit access to compartment Cl In the preferred form, the compartments C1 , C2 are configured to receive one or more audio and/or visual media, such as compact discs or portable music players.

Details of the door assembly of the preferred embodiment will now be described with reference to Figure 1 C. The door assembly, generally indicated with numeral 102, includes the housing 104 on which the door 103 having a door base 106 is slidably mounted. The housing 104 includes a generally planar surface that has one or more openings into the equipment, although the one or more openings are not shown in the figure and the planar surface is instead shown as a solid plane for clarity.

To guide the sliding movement of the door, projections or guideways (generally shown as 105) are provided along or adjacent the edges 101a, 101 b of the housing 104 and the door base 106. Adjacent the edge 101b of the door base 106, a first track and a second track, shown as a first toothed rack 110 and a second toothed rack 112, are provided. As will be described below, the first toothed rack 110 allows the door to slide in a first direction 116 to a first open position, while the second rack 112 allows the door to slide in a second direction 114 to a second open position. Specifically, the first toothed rack 110 allows the door 103 to be driven to the first open position, while the second toothed rack 112 allows the door 103 to be driven to the second open position. As shown in Figure 1C, the first direction 1 16 is substantially opposite to the second direction 114.

A third track, shown as a cam gear 1 18, is also provided in the door base 106. The door base 106 and cam gear 118 together form a door base unit. The cam gear 118 is specifically arranged between the first toothed rack 110 and second toothed rack 1 12 and separates first toothed rack 1 10 and second toothed rack 112. The first toothed rack 110 and second toothed rack 1 12 are therefore positioned on opposite sides of the cam gear 118. The cam gear 118 includes a first end 118a and a second end 1 18b and is movable to a first position to align the first end 118a with the first toothed rack 110, and is moveable to a second position to align the second end 118b with the second toothed rack 1 12. In the figure illustrated, the cam gear 118 is in the second cam position and has teeth arranged in an arcuate path.

Rotatably mounted to the housing 104 is a driven wheel or driven gear 120. The driven gear 120 can be driven by any conventional motor or like driving mechanism so as to rotate (in its position on the planar surface, i.e. on a stationary rotational axis) and engage the first toothed rack 110, second toothed rack 112 and cam gear 118. As the housing 104 is fixed relative to the equipment and as the driven gear 120 is rotatably fixed to the planar surface of the housing 104, rotation of the driven gear 120 effectively pushes or pulls the door 103 by virtue of the teeth of the driven gear 120 meshing with those of the first toothed rack 110 or the second toothed rack 112, which results in the rotational motion of the driven gear 120 being converted into translational motion of the door 103.

Figures 2A and 2B show a detailed view of the door base 106 of Figure 1C. When assembled in the door assembly, the door base 106 is parallel to and faces the planar surface of the housing. Edges 101a, 101b of the door base 106 are provided with guideways to be slidably received in corresponding guideways along edges of the planar surface. Adjacent edge 101 b of the door base 106, the first toothed rack 110 and the second toothed rack 1 12 are provided. The first and second toothed racks 110, 112 have corresponding teeth and are integral with the door base 106. Dividing and separating the first and second toothed racks 110, 112 by a gap G is a recess 200 (best depicted in Figure 2B), which is also provided in the door base 106. In the embodiment illustrated, the recess 200 is arranged substantially in the centre of the edge 101b adjacent to which the first and second toothed racks 1 10, 112 are provided. The recess 200 as shown has a generally circular shape with a curved groove 202 along a top portion of the circular shape. The groove 202 defines a first limit 202a and a second limit 202b that are configured to receive a projection of the cam gear 118 for positional placement. The recess 200 is defined in part by a first step 208a and a second step 208b that control the extent to which the cam gear is movable. Details of this control will be described later with reference to Figures 8A to 8D. The recess 200 also includes a pivot structure 204 including a guide 206 for pivotally fixing the cam gear to the door base 106. The pivot structure 204 as shown is a substantially cylindrical projection in the recess 200, while the guide 206 comprises a post projecting from the surface of the recess 200 and an arm attached to and extending substantially perpendicularly to the post. The post and arm of the guide 206 are best depicted in Figure 8A.

Referring now to Figures 3A to 3D, the cam gear of the preferred embodiment is generally shown as 118. As best depicted in Figure 3B, the cam gear 118 has a substantially quadrant shape with first and second sides 300, 302 each configured to abut respectively the first and second steps of the recess in the door base. The cam gear 118 includes teeth 304 provided along the arc of the quadrant shape, defining an arcuate path, and has a first end 118a and a second end 118b. The first and second ends 118a, 118b are also tapered to match a tapered end of the first and second toothed racks of the door base to allow the cam gear to pivot to and from its alignment with the first and second toothed racks. The cam gear 1 18 further includes an aperture 310 and a slot 312 configured to receive the recess pivot structure and guide respectively. The slot 312 includes a guide opening 314 that is configured to receive the arm of the guide during assembly, the guide opening 314 being otherwise out-of- bounds during normal operation of the door assembly. The teeth 304 are arranged on the quadrant shape of the cam gear 118 such that, when the cam gear 118 is assembled in the recess of the door base, the teeth 304 are on the same plane as the first and second toothed racks. In the preferred embodiment, therefore, the thickness of the quadrant shape of the cam gear 118 is substantially the same as the depth of the recess. The teeth 304 are relatively thicker than the quadrant shape, as illustrated in Figure 3D, to ensure the teeth 304 are able to align with the first and second toothed racks when the cam gear 118 is assembled in the door base. The cam gear 118 of the preferred embodiment also includes a tip 316, shown in Figure 3C, having a tab or projection 318 configured to be received in the groove of the recess in the door base.

Figures 4A and 4B show the cam gear 118 attached to the door base 106, forming the door base unit 400. In this assembled form, the pivot structure 204 and the guide 206 of the recess 200 extend through the aperture and slot of the cam gear 118, and the projection of the cam gear tip 316 is received in the groove 202 of the recess 200. Figures 4A and 4B show the first position of the cam gear 118, where the first end 118a of the cam gear 118 (specifically of the teeth 304) is aligned with the first toothed rack 110. As will be described in detail below, the cam gear 118 is pivotable from the first position to a second position where the second end 118b of cam gear 118 (specifically of the teeth 304) is aligned with the second toothed rack 112. In the preferred embodiment, the pivoting of the cam gear 118 between the first and second positions is the result of a driven rotation (e.g. rotation by a motor) the driven gear when engaged with the cam gear 118. Specifically, depending on the starting position of the cam gear 118 and the direction of rotation of the driven gear, the cam gear 118 either remains in place to allow the driven gear to engage with and effectively push or pull the first or second toothed rack to which the cam gear 118 is aligned, or pivots to the first or second position to align with one of the first or second toothed rack before allowing the driven gear to effectively push or pull the respective toothed rack. This operation will be described later in further detail.

Figures 5A and 5B show the housing 104 including a planar surface 500. The planar surface 500 includes one or more openings (not shown) into the housing. As noted earlier, the planar surface 500 is shown as a solid plane for clarity. Also as noted earlier, both edges 101a, 101 b of the housing 104 are provided with projections configured to allow slidable coupling with the edges of the door base. As illustrated in Figure 5B, the projections are in the form of guideways 502 and 504. In the preferred embodiment, the driven gear 120 is arranged adjacent the edge 101 b of the planar surface 500 and substantially in the centre of the length L of the edge 101b to drive the door between a closed position (where all of the one or more openings of the housing are closed by the door) and the first and second open positions (where some or all of the openings of the housing are accessible). The location of the driven gear 120 also defines the position of the door in the closed position (herein the 'home position').

The operation of the door assembly according to the preferred embodiment will now be described with reference to Figures 6A to 6C and 7A to 7C. The viewpoints of Figures 6A to 6C and 7A to 7C are of the back of the door assembly, similar to the view shown in Figure 1C. Skilled persons will appreciate that this back view of the door assembly effectively shows the housing and its openings (i.e. compartments C1 , C2) first, then the driven gear, followed by the cam gear in the door base and the door, in that order. It is also clear that the positions of the compartments C1 , C2 with respect to each other from the back view are the reverse of their positions in the front perspective view of Figures 1A and 1 B. For clarity, the above figures illustrate all relevant components in solid lines, regardless of their position behind other components. For instance, the first and second toothed racks are shown in solid lines despite being behind the housing in the view shown. It is expected that skilled persons will be able to discern the relative positions of components of the door assembly in view of the earlier detailed description of the structure of the assembly. Also for clarity, an enlarged illustration of the driven gear is provided on the sides of Figures 6B, 6C, 7B and 7C to show the direction of rotation of the driven gear. In the preferred embodiment illustrated, the door is configured to open in a first direction to provide access to a first compartment C1 in the housing, and is configured to open in a second direction to provide access to a second compartment C2 in the housing. The sliding of the door is centralized such that when the door is in the first open position, the first compartment C1 is accessible but not the second compartment C2, and when the door is in the second open position, the second compartment C2 is accessible but not the first compartment Cl In Figures 6A to 6C, the operations depicted show the door being moved from a home position to a second open position and back to the home position, whereas in Figures 7A to 7C, the operations depicted show the door being moved from the home position to a first open position.

Starting with Figure 5A, the driven gear 120 is shown engaged with the cam gear 118, with the projection of the cam gear tip 316 at the second limit 202b of the groove 202 and the first side of the quadrant shape of the cam gear 118 abutting the first step of the recess. This defines the second position of the cam gear 118. At this point, the door of the assembly is at the home position.

In Figure 6B, the driven gear 120 is shown rotating clockwise in response to instructions to open the door to a second open position. Given the pivotable disposition of the cam gear 118, the clockwise rotation of the driven gear 120 will first seek to pivot the cam gear clockwise. Given the starting position in Figure 6A, where the first side of the quadrant shape is already at its limit (i.e. the first step 208a, thus preventing further clockwise pivoting of the cam gear 118), the cam gear 118 does not pivot under rotation of the driven gear 120. Instead, the clockwise rotation of the driven gear 120 results in the driven gear 120 meshing with the cam gear 118 and ultimately the second toothed rack 112. Since the driven gear 120 is fixed to the housing, the meshing movement of the driven gear 120 effectively pushes the second toothed rack 112, and thus the door, in a second direction B, resulting in the door being slid toward the second open position. This provides access to the second compartment C2. It will be appreciated that Figure 6B shows only a partial opening in the second direction B since the driven gear 120 has only traveled part of the length of the second toothed rack 112. When opened to the full extent of the second open position, all of the second compartment C2 will be accessible. Skilled persons will appreciate that a simple position sensor may be used to determine when the door has reached the second open position. The first compartment C1 at this point remains covered by the door. On instructions to close the door (i.e. return it to the home position), the driven gear

120 rotates anticlockwise and effectively pulls the second toothed rack 112, and thus the door, in the direction A, back towards the home position as shown in Figure 6C. When the driven gear 120 leaves the second toothed rack 112 and meshes with the cam gear 118, the door movement in the direction A stops since further anticlockwise rotation of the driven gear 120 when it is meshed or engaged solely with the cam gear

118 will only cause pivoting of the cam gear 118. A simple position sensor is then used to determine that driven gear 120 has reached the cam gear 118 and to stop the driven gear from further rotation.

Referring now to Figures 7A to 7C, the transition between the home position and a first open position is shown. In Figure 7A, the cam gear 118 is shown to be in a position between the first and second positions defined by the recess steps. Rotation anticlockwise by the driven gear 120 at this point pivots the cam gear 118 anticlockwise. When the other side of the cam gear's quadrant shape reaches and abuts the second step of the recess, as shown in Figure 7B, the cam gear 118 is in the first position. In the embodiment illustrated, a rotation of the cam gear 1 18 by 90° moves the cam gear 118 between the first and second positions. In the first position shown in Figure 7B, the first end 118a of the cam gear 118 is aligned with the first toothed rack 110, and further anticlockwise rotation of the driven gear 120 does not pivot the cam gear 118 further. As such, any further anticlockwise rotation results in the driven gear 120 meshing with the cam gear 118 out to the first toothed rack 110. As before, since the driven gear 120 is fixed to the housing, the meshing of the driven gear 120 with the cam gear 118 and the first toothed rack 110 effectively pushes the first toothed rack 110, and thus the door, in a first direction A, resulting in the door being slid toward the first open position. This provides access to the first compartment C1. As before, it will be appreciated that Figure 7C shows only a partial opening of the first compartment C1. Full access to the first compartment C1 will be achieved once the driven gear 120 has traveled the length of the first toothed rack 110 (determinable using a simple position sensor). Also as before, the door assembly is configured such that the second compartment C2 remains covered by the door when the first compartment C1 is accessed.

Referring now to Figures 8A to 8D, the pivoting of the cam gear in the recess of the door base is shown in greater detail. Figure 8A shows details of the recess 200 with the pivot structure 204 and the guide 206. The groove 202 is shown having projections or tabs 800a and 800b adjacent the first and second limits 202a, 202b respectively. The tabs 800a and 800b are configured to secure a projection of the cam gear tip in place at the first or second limits 202a, 202b. In essence, therefore, the tabs 800b, 800b provide temporary positional locking of the cam gear. This temporary positional locking can be seen in Figures 8B and 8C. The figures respectively show the tabs 800a, 800b securing or locking the cam gear 118 at the first and second limits 202a, 202b respectively. In the preferred form, each tab comprises a pair of oppositely-inclined surfaces defining a peak.

By having the cam gear 118 secured in either the first or second position, it can be ensured that the cam gear 1 18 remains aligned with the respective toothed rack to receive the driven gear 120 as the door returns from the first or second open position to the home position. This accordingly reduces the risk of the cam gear 118 moving to an intermediate position between the first and second positions while the driven gear 120 is on one of the first or second toothed rack 110, 112, as shown in Figure 8D, which would prevent the door from returning to the home position.

It is advantageous for the above operation that the tip of the cam gear be substantially flexible. As shown in Figure 9, the tip 316 of the cam gear 118 is sufficiently flexible in the direction F so as to be able to traverse or rise over the tabs in the grooves under rotation of the driven gear to secure the projection of the tip 316 at one of the first and second limits.

Figures 10A to 10C show a further advantageous operation of the preferred embodiment. Specifically, once the door has been returned to the home position, the driven gear 120 is configured to rotate the cam gear 118 to a third position between the first and second positions noted earlier. In this arrangement, both the first end 118a and the second end 1 18b of the cam gear 118 are out of alignment with the first toothed rack 110 and the second toothed rack 112 respectively. As such, if a force is applied to the door in the direction A shown in Figure 10B, rotation of the driven gear 120 is restricted by the arcuate path defined by the teeth of the cam gear 118. Similarly, if a force is applied to the door in the direction B shown in Figure 10C, rotation of the driven gear 1^'20 is also restricted by the arcuate path defined by the teeth of the cam gear 118. This can be contrasted with conventional arrangements where toothed racks on doors are always in contact with the driven gear. In such arrangements, if sufficient force is applied in the direction of the toothed rack, the driven gear meshes with the toothed rack and allows the door to be moved. Accordingly, even if the equipment is turned off, it is possible for the door to be misaligned from its closed position. This problem can be addressed by using the cam gear as outlined above.

Referring to Figure 11 , a further locking advantage may be realized by incorporating one or more extensions 1 100, 1102 in the door assembly. The extensions 1100, 1102 are provided on the planar surface of the housing, adjacent the driven gear 120. In particular, the extensions 1100, 1102 are disposed circumferentially of the driven gear 120, and between the driven gear 120 and the cam gear 118 when the cam gear 118 is in the third position. With the extensions 1100, 1102 in place, the driven gear 120 is further restricted from moving toward the first or second ends 118a, 118b of the cam gear 118 under force in the directions shown in Figures 10B and 10C. The extensions 1100, 1102 do not interfere with the normal operation of the driven gear 120 since a driven rotation of the driven gear 120 would cause the cam gear 1 18 to pivot as described above without being obstructed by the extensions 1100, 1102. In particular, skilled persons will appreciate from the description above that it is not the driven gear 120 that translates along the first and second tracks 110, 112; rather, the first and second tracks 1 10, 120 are pushed away from and pulled toward the home position by the rotating but otherwise fixed driven gear 120. In such an operation, the extensions 1100, 1102 do not operate as obstructions. The extensions 1100, 1102 only obstruct a movement of the driven gear 120 laterally sideways, thus creating locking in a sideward motion when the driven gear is not being driven.

As will be appreciated from the above description, the preferred embodiment of the present invention provides a mechanically-controlled home position (i.e. by way of a cam gear) for a door movable in two directions. In particular, the use of the cam gear provides a simple yet robust mechanically-controlled mechanism that stabilizes the home position of a door movable to two open positions, such as left and right, up and down, diagonally-opposed movement or V-shaped movement, relative to a home position. The home position is clearly stabilized since there is no longer a fine threshold defining the closed position; as soon as the driven gear leaves the toothed racks and engages the cam gear, the door will be in the home position and any inaccuracies (e.g. from a non-precise motor) leading to a slight over-rotation of the driven gear will not shift the door from the home position. Clearly then, the mechanism above allows the door assembly to reveal and hide one or more openings or compartments of an equipment or product by a movement in two directions relative to a centralized home position without having to rely on complex software-feedback control systems, expensive detection devices/sensors or precision motors to control the home position. The use of the cam gear thus provides a cost-effective solution to provide a stable home position.

An unexpected benefit from providing the above mechanically-controlled home position is that the cam gear may improve the locking of the door in the home position by virtue of the separation of the cam gear from the first and second toothed racks. In the preferred embodiment, this is put into effect by arranging the teeth of the cam gear in an arcuate path and configuring the cam gear for pivotal movement. In this arrangement, the cam gear is effectively blocked from moving laterally by the driven gear. As such, when the driven gear is engaged with the cam gear and the cam gear is positioned between the first and second positions (thus misaligning the first and second ends of the cam gear with respect to the first and second toothed racks respectively), lateral movement of the driven gear is substantially prevented. This in turn means that, once the door is in its home position and the driven gear and cam gear are positioned as noted above, the door is further stabilized in its home position.

Although the present invention has been described above with reference to a preferred embodiment, many variations are possible within the scope of the claims, as will be clear to a person skilled in the art. For example, although the housing described in the preferred embodiment includes two openings, a single opening will suffice. In the latter case, the door assembly may provide access to different spaces within the opening when the door is positioned at the first and second open positions.

Also, although the preferred embodiment utilizes toothed tracks, this is not essential. Skilled persons will appreciate that the invention may be put into practice using flat tracks with a sufficient friction co-efficient for engagement with a driven rubber wheel.

Similarly, the first and second tracks need not be substantially the same length. Where one open position should provide access to a larger interior space than another open position, the first and second tracks may have substantially unequal lengths. As for the third track, skilled persons will appreciate that any track that separates the first and second racks and that is movable to align selectively with one of the first and second racks may be put to use. An arcuate path cam gear is therefore not essential. For instance, a shallow V-shaped cam gear or third track may be used.

Claims

1. A door assembly comprising: a housing having rotatably mounted thereto a driven wheel, and a door slidably mounted to the housing, the door having a first track configured to engage the driven wheel to slide the door to a first open position, a second track configured to engage the driven wheel to allow the door to slide to a second open position, and a third track being movable by the driven wheel between a first position to enable the driven wheel to engage with the first track and a second position to enable the driven wheel to engage with the second track.

2. The door assembly of claim 1 , wherein the first track is a first toothed rack, the second track is a second toothed rack, the third track is a cam gear, and the driven wheel is a driven gear.

3. The door assembly of claim 2, wherein the first and second toothed racks are fixed to the door and are separated by a recess in which the cam gear is positioned.

4. The door assembly of claim 3, wherein the cam gear includes a projection configured to be received in a groove provided in the recess.

5. The door assembly of claim 4, wherein one or more projections are provided in the groove, the one or more projections being configured to secure the cam gear in the first position or the second position.

6. The door assembly of any one of claims 2-5, wherein the door includes a pivot structure, the cam gear being pivotable between the first position and the second position about the pivot structure.

7. The door assembly of any one of claims 2-6, wherein the cam gear is configured to pivot by about 90° to move between the first position and the second position.

8. The door assembly of any one of claims 2-7, wherein the cam gear is further pivotable to a third position between the first position and the second position, the third position being such that the first end of the cam gear is misaligned with the first toothed rack and the second end of the cam gear is misaligned with the second toothed rack.

9. The door assembly of any one of claims 2-8, wherein the cam gear includes teeth arranged in an arcuate path.

10. The door assembly of claim 9, wherein the cam gear has a substantially quadrant shape, and wherein the arcuate path is along an arc of the quadrant.

11. The door assembly of any one of claims 2-10, wherein the housing includes a planar surface parallel to the door, and wherein the driven gear is rotatably mounted on the planar surface.

12. The door assembly of claim 11 , wherein the planar surface has an edge having a length, the driven gear being rotatably mounted adjacent the edge and substantially in the centre of the length.

13. The door assembly of claim 12, wherein the first and second toothed racks are provided adjacent an edge of the door.

14. The door assembly of any one of the preceding claims, wherein the door assembly forms part of an audio and/or visual equipment, and wherein the housing includes an opening configured to receive one or more audio and/or video media.