NZ552200A - An extendable mounting system for a slidable barrier - Google Patents

Abstract

An extendable mounting system for a slidable barrier, the extendable mounting system including at least one track member each having at least one opening therein; at least one removably attachable track extension portion and mounting means to removably attach the at least one track extension portion relative to the at least one track member laterally of the at least one track member to increase the number of track openings available for use in the system.

Description

55 1 AN EXTENDABLE MOUNTING SYSTEM FOR A SLID ABLE BARRIER Field of the Invention.

The present invention relates to mounting systems for a slidable barrier such as a wardrobe, door or other panel and particularly to mounting systems which 5 are easily extendable to incorporate multiple panels.

Background Art.

Sliding panels are commonly used for covering openings in buildings, as well as in retail store display cases or showcases that incorporate glass front, side and even back walls to prominently display products, for example. 10 The sliding "doors" are generally provided in conjunction with a mounting system that includes one or more tracks to enable the sliding door with a guide or path upon which to slide. There is generally an upper track member or head member and a lower track member or sill member provided as a part of the mounting system. Generally, each track member may include single or multiple tracks for a 15 sliding door panel. The number of tracks provided is generally two depending upon the number of sliding door panels provided in the system, which is also normally 2. Normally, a track is provided on each track member for each door panel.

The track members provided according to the prior art are normally provided as extruded members of either plastic or metal. The track members are rigid 20 members having a predetermined number of tracks.

Head track members and sill track members typically have different configurations with the upper track (or head) member normally allowing the movement of the sliding door only in lateral directions.

Each upper track member therefore generally includes at least one 25 section of a straight channel that has a pair of parallel side walls that extend at substantially right angles from a base wall to form aligned substantially flat flanges defining a channel therebetween to accommodate a sash of the sliding door travelling therebetween.

The bottom or sill track member is generally provided as a guide only 30 and supports the door panel. The normal manner of fitting the door panel into the opening once the head and sill track members have been fixed in the opening is by inserting the upper end of the door panel between the substantially parallel side walls of the channel of the head member, rotating the lower portion of the door inwardly, then lowering the door panel onto the sill track member. Normally a guide track is provided in the sill track member to assist with alignment of the door panel.

Sliding door systems as described above have some disadvantages, namely that the systems must be custom fitted into an opening depending upon a 5 number of parameters such as the width of the opening and the number of doors to be fitted. Once a track having a pair of tracks is chosen, the number of doors that can be used in the system or the distance that a user is able to slide the doors from side to side, is fixed to a pair. The systems therefore lack versatility in this respect.

It will be clearly understood that, if a prior art publication is referred to 10 herein, this reference does not constitute an admission that the publication forms part of the common general knowledge in the art in Australia or in any other country.

Summary of the Invention.

The present invention is directed to an extendable mounting system for a slidable barrier, which may at least partially overcome at least one of the 15 abovementioned disadvantages or provide the consumer with a useful or commercial choice.

In this specification, we have used the term "track member" to refer to a member of the mounting system and the term "track" to refer to a single slide path along which a slidable barrier moves.

In one form, the invention resides in an extendable mounting system for a slidable barrier, the extendable mounting system including i. at least one track member each having at least one opening therein, ii. at least one removably attachable track extension portion and iii. mounting means to removably attach the at least one track extension portion 25 relative to the at least one track member to increase the number of openings available for use in the system.

The inventors of the system according to the present invention believe that the system provides increased functionality for the mounting system for a slidable barrier. The system of the present invention will typically allow a user to extend a 30 slidable barrier assembly which is already in place without requiring a completely new made-to-measure system to be ordered and installed. The system of the present invention can be extended when required and also reduced if it becomes too large, quickly, easily and at low cost.

The present invention is an extendable mounting system for a slidable barrier. Slidable barriers are typically used to provide a moveable barrier to cover an opening. The slidable barrier is normally mounted in the opening using a mounting system which is sized to fit within the opening and then one or more slidable barrier elements are inserted into the mounting system.

As discussed above, mounting systems for slidable barriers normally include a head member and a sill member. The head member is generally located at an upper side of the opening and the sill member is generally located at a lower side of the opening. There may be side or jamb members located at either side of the opening and one or both jamb members may carry locking means to secure the slidable barrier elements in the closed condition.

The extendable mounting system according to the present invention can be used in association with any slidable barrier element such as wardrobe doors, sliding windows, doors, shower screens, privacy screens, gates or the like. The mounting system of the invention is more applicable to internally located doors or room dividers as the issues of water and wind penetration must be surmounted. However, the system will typically be used in situations where the opening is surrounded by an accessible area capable of supporting the extension portions where added to the system. For this reason, the system is particularly well suited for use in sliding door systems such as wardrobe doors or room dividers.

The system of the present invention is particularly useful for internal non-security doors such as wardrobes that are already provided with an opening of particular dimensions between the floor and the ceiling. One or more (typically a number of) barrier elements are generally provided in the slidable barrier system.

The barrier element will typically slide on guides, runners, bearings, or wheels. These may be mounted for rotation parallel to the barrier member or perpendicular thereto to maintain spacing. A typical example used in a conventional barrier member system is a wheel which rests in a groove or channel in the sill and/or head member and supports the slidable barrier element.

Further, in conventional barrier member systems, the barrier elements normally rest on the sill member and are restricted to longitudinal movement only by the configuration of the head member. In this specification, the longitudinal direction is in relation to the head or sill member and towards one of the side jamb members. The lateral direction refers to a direction perpendicular to the plane of the opening.

The system further includes at least one track member with each track member having at least one opening therein.

As discussed above, sliding door systems normally include an upper track or "head" member and an opposed, lower track or "sill" member. These members may be termed the "fixed head" and "fixed sill" members respectively to distinguish them from the extension portions of the present invention. There may be systems available that include only one fixed member as such and guides in the 10 replacement of the other of the fixed members.

Typically, both the fixed head and the fixed sill member will be formed by extrusion technology and cut to any required length. As the members will generally be extruded, they will normally have a constant cross-section over their length.

Each of the fixed head and fixed sill members will also typically 15 include one or more attachment portions or assemblies to mount the fixed members in, or relative to, the opening to be covered by the barrier elements.

The fixed members of the system may be manufactured of any material but normally metal or plastic will be used as these materials provide the required strength characteristics as well as being light and robust.

Each mounting system may incorporate more than one of each fixed member, generally longitudinally aligned to span an opening. Where this occurs, the fixed members may be provided with engagement or attachment portions to secure the fixed members relative to one another.

Each fixed head member generally includes at least one section of a 25 straight channel having a pair of side walls that extend substantially at right angles from a base wall to form aligned flat flanges and defining a channel therebetween to accommodate a carriage of the sliding barrier element travelling therebetween.

Each fixed head member of the present invention will generally include a pair of channels which are oriented parallel to one another. The pair of channels are 30 typically defined by three spaced apart side walls that extend substantially at right angles from a base wall, the middle of the three walls separating the pair of channels.

The side walls of the fixed head member may be planar or shaped, depending upon the desires of the user with regard to aesthetics. Generally however, the middle wall will be planar as will the inner faces of the two outer walls as this will assist with the guidance of the barrier elements when they are being moved.

The attachment portions provided may be as simple as the provision of a plurality of openings through the base wall through which screws or other fasteners 5 may be inserted to fix the head member to the surrounds of the opening.

The bottom or sill track member is generally provided as a guide only and supports the slidable barrier element. Normally, a guide track is provided in the sill track member to assist with alignment of the slidable barrier element.

Preferably, the guide track is a longitudinally extending recess or dip. 10 It is also anticipated that the guide track may be a raised ridge or rail. The ridge may be arcuate. Normally, the ridge would engage with a wheel or similar provided on the barrier element, the wheel having a circumferential groove to engage the ridge to restrict the barrier element from moved off the rail.

The more preferred configuration of the guide track is as a dip or 15 depression in the sill member. Such a dip or depression will normally have raised portions located to either side and these may assist with the aim of the mounting system by preventing lateral movement of the slidable barrier element.

The attachment portions provided may be as simple as the provision of a plurality of openings through the base wall through which screws or other fasteners 20 may be inserted to fix the head member to the surrounds of the opening.

The normal manner of fitting the slidable barrier element into the opening once the fixed head and sill track members have been secured in the opening is by inserting the upper end of the slidable barrier element between the parallel side walls of the respective channel, rotating the lower portion of the slidable barrier 25 element inwardly then lowering the slidable barrier element onto the sill track member to properly locate any guide members on or into the guide track provided.

The system of the invention also includes at least one removably attachable track extension portion.

Typically, the track extension portions provided for both the head 30 member and the sill member maintain the symmetry of the extendable mounting system. As such, the extension portions will generally be provided as a pair of extension portions, one for the head member and one for the sill member.

As the head and sill members of the mounting system are configured differently, so the respective extension portions will preferably also be configured differently to one another.

Each respective head and sill extension portion will typically be similar 5 in configuration to a single track from the respective head or sill track member.

According to a preferred embodiment, the head extension portion will typically include a side wall that extends substantially at right angles from a base wall to form an L-shaped member. In use, the side wall of the head extension portion is attachable to the fixed head member of the system and be aligned to be substantially 10 parallel to a sidewall of the existing head member and define a channel therebetween. The channel is adapted to receive a slidable barrier element in a manner similar to the channels of the fixed head member.

According to a preferred embodiment, the sill extension portion will include a single guide track. As with the fixed sill member, the guide track of the sill 15 extension portion is typically configured as a dip or depression in the sill extension portion. Such a dip or depression will normally have raised portions located to either side.

More than one extension portion may be used with each fixed member. A single or double track system may be expanded to include any number of tracks 20 depending upon the space available and the desires of the user. More than one extension portion can be used to span the length of the opening and more than one extension portion may be used to expand the fixed mounting system laterally.

For example, a track extension portion may be mounted to a track extension portion or to the fixed head or sill member.

The system of the present invention includes mounting means to removably attach the at least one track extension portion relative to the at least one track member to increase the number of openings available for use in the system.

The mounting means to attach the extension portions relative to the fixed track members may be associated with the fixed members or extension portions 30 which are in turn mounted to the fixed track member.

Generally, the mounting means will be a multi-part means and will include a portion provided on each of the fixed member and the extension portion of the respective head and sill. Each part of the multi-part mounting means will preferably engage the other of the parts to fix the extension portion relative to the fixed member.

Again, due to the differences in configuration of the head member and sill members, the mounting means used in the respective configurations will typically 5 differ between the head and the sill members.

As regards the head member mounting means, a recess or opening adapted to engage a flange portion is preferably provided on either the fixed or extension portion, but normally the fixed head member. The recess or opening is typically provided on the fixed head member proximally at or adjacent the meeting of 10 the outer sidewalls and the base wall(s). According to a more preferred form, the recess or opening is a partially U-shaped opening having an outer wall extending from the side wall of the head member but not as far as to be co-planar with the base wall. The opening generally extends over the length of the fixed head member.

The other of the fixed or extension portion generally includes the 15 flange portion in the form of a depending flange on the free end of the base wall of the extension portion. Preferably, the flange portion depends substantially perpendicularly from the base wall such that when the flange portion is properly located in the U-shaped opening in the fixed head member, the base wall of the extension portion is coplanar with the base wall of the fixed head member and the side wall of the 20 extension portion is substantially parallel to the side walls of the fixed head member. The flange portion generally extends over the length of the extension head member.

The head extension portions will also be provided with a portion of the mounting means at or adjacent the free end of the base wall and the matching portion at or adjacent the meeting of the sidewall and the base wall to allow the mounting of 25 further extension portions thereto.

As regards the sill member mounting means, a recess or opening adapted to engage a flange portion is preferably provided on either the fixed or extension portion, but normally the fixed sill member. The opening is normally a downwardly diverging opening.

The other of the fixed or extension sill portion, most preferably the extension portion, has an upwardly extending flange on an edge. The flange typically extends upwardly substantially perpendicularly to the sill extension member to engage with the downwardly diverging opening. 8 The sill extension portions will also generally be provided with the part of the mounting means at or adjacent one side edge and the other part of the multi-part mounting means at or adjacent the opposite side edge to allow the mounting of further extension portions thereto.

Brief Description of the Drawings.

Various embodiments of the invention will be described with reference to the following drawings, in which: Figure 1 is a perspective view of a head mounting member of a slidable barrier system with an extender portion in the partially installed or "fitting" condition.

Figure 2 is a perspective view of the head mounting member illustrated in Figure 1 with the extender portion fully installed.

Figure 3 is a perspective view of the head mounting member illustrated in Figure 2, with a further extender portion in the partially installed or "fitting" condition.

Figure 4 is a perspective view of a sill mounting member of a slidable barrier system with an extender portion in the partially installed or "fitting" condition.

Figure 5 is a perspective view of the sill mounting member illustrated in Figure 4 with the extender portion fully installed.

Figure 6 is a perspective view of the sill mounting member illustrated in Figure 5, with a further extender portion in the partially installed or "fitting" condition.

Detailed Description of the Preferred Embodiment.

According to the preferred embodiment of the invention illustrated, an extendable mounting system for a slidable barrier is provided.

The extendable mounting system includes a fixed head track member 10 as illustrated in Figure 1 and a fixed sill track member 11 as illustrated in Figure 4, each having an opening therein for partially receiving a slidable barrier element (not shown). The system also includes at least one removably attachable track extension portion for each fixed track member 10, 11 and mounting means to removably attach the track extension portions relative to the fixed track members 10, 11 to increase the number of openings available for use in the system. 9 Typically, both the fixed head 10 and the fixed sill 11 member are formed by extrusion technology and cut to the required length. As the members 10, 11 are extruded, they have a constant cross-section over their length.

Each fixed head member 10 of the preferred embodiment illustrated 5 includes two channels 12 defined by a pair of side walls 13 that extend substantially at right angles from a base wall 14 defining the channels 12 therebetween to accommodate the sliding barrier element (not shown) travelling therebetween.

Each of the channels 12 of the fixed head member 10 of the illustrated preferred embodiment are oriented parallel to one another. The two channels are 10 defined by three spaced apart side walls 13 that extend substantially at right angles from a base wall 14, the middle of the three side walls 13 separating the pair of channels 12. The side walls 13 of the fixed head member 10 are planar or very nearly so.

The fixed sill track member 11 according to the preferred embodiment 15 illustrated is provided as a guide only and supports the slidable barrier element (not shown). Normally, a guide track 15 is provided in the fixed sill track member 11 to assist with alignment of the slidable barrier element.

The guide track of the preferred embodiment illustrated is a longitudinally extending opening in the form of a recess or dip. Such a dip or 20 depression has raised portions 16 located to either side and these assist with the aim of the mounting system by preventing lateral movement of the slidable barrier element.

The normal manner of fitting the slidable barrier element into the opening once the fixed head 10 and sill 11 track members have been secured in the opening is by inserting the upper end of the slidable barrier element between the 25 parallel side walls 13 of the respective channel 12, rotating the lower portion of the slidable barrier element inwardly, then lowering the slidable barrier element onto the sill track member to properly locate any guide members on or into the dip 15 provided.

In order to provide the advantages of the system of the invention, it also 30 includes at least one removably attachable track extension portion for each respective fixed track member 10, 11, namely a head extension portion 17 and a sill extension portion 18.

The track extension portions 17, 18 are provided as a pair of extension portions, one for the fixed head member 10 and one for the fixed sill member 11.

As the head and sill members of the mounting system are configured differently, so the respective extension portions are configured differently to one 5 another.

Each respective head 17 and sill 18 extension portion are similar in configuration to a single track from the respective fixed head 10 or fixed sill 11 track member.

According to the preferred embodiment illustrated in Figures 1 to 3, the 10 head extension portion 17 includes a side wall 13a that extends substantially at right angles from a base wall 14a to form an L-shaped member. In use, the side wall 13a of the head extension portion 17 is attachable to the fixed head member 10 of the system and can be aligned to be substantially parallel to a sidewall 13 of the fixed head member 10 and define an extension channel 12a therebetween. The extension channel 15 12a is adapted to receive a slidable barrier element in a manner similar to the channels of the fixed head member 10.

According to the preferred embodiment illustrated in Figures 4 to 6, the sill extension portion 18 includes a single guide track 15a. As with the fixed sill member 11, the guide track 15a of the sill extension portion 18 is configured as a dip 20 or depression in the sill extension portion 18. Such a dip or depression has raised portions 16a located to either side.

As illustrated in Figures 3 and 6, more than one extension portion 17, 18 can be used with each fixed member 10, 11. As illustrated in Figures 3 and 6, a double track system can be expanded to include any number of tracks depending upon 25 the space available and the desires of the user. More than one extension portion can be used to span the length of the opening and more than one extension portion may be used to expand the fixed mounting system laterally.

For example, a track extension portion can be mounted to a track extension portion as illustrated in Figures 3 and 6, or to the fixed head 10 or sill 11 30 member as illustrated in Figure 1 and 2 and Figures 4 and 5.

The system of the present invention includes mounting means 19 to removably attach the track extension portions 17, 18 relative to the respective fixed 11 track members 10, 11 to increase the number of openings to receive a slidable barrier element (not shown) available for use in the system.

According to the particularly preferred embodiment illustrated, the mounting means 19 is a multi-part means and includes a part provided on each of the 5 respective fixed members 10, 11 and extension portions 17, 18. Each part of the multi-part mounting means engages the other of the parts, to fix the respective extension portions relative to the fixed members.

Again, due to the differences in configuration of the head member and sill members, the mounting means used in the respective configurations will typically 10 differ between the head and the sill members.

The fixed head member 10 is provided with a recess or opening 20 adapted to engage a flange portion 21 as illustrated in Figure 1. The recess or opening is provided on the fixed head member 10 proximally at or adjacent the meeting of the outer sidewalls 13 and the base wall 14. According to a more preferred form, the recess or opening 20 is a partially U-shaped opening having an outer wall 22 extending from the side wall 13 of the head member but not as far as to be co-planar with the base wall 14. The opening 20 extends over the length of the fixed head member 10.

The head extension portion 17 includes the flange portion 21 in the 20 form of a depending flange on the free end of the base wall 14a of the head extension portion 17. The flange portion 21 depends substantially perpendicularly from the base wall 14a such that when the flange portion 21 is properly located in the U-shaped opening 20 in the fixed head member 10, the base wall 14a of the head extension portion 17 is coplanar with the base wall 14 of the fixed head member 10 and the side 25 wall 13a of the head extension portion 17 is substantially parallel to the side walls 13 of the fixed head member 10. The flange portion 21 extends over the length of the head extension member 17.

The head extension members 17 are provided with the flange portion 21 at or adjacent the free end of the base wall 14a and a recess or opening 20 similar 30 to that provided on the fixed head member 10, at or adjacent the meeting of the side wall 13 and the base wall 14 to allow the mounting of further extension portions 17 thereto. 12 The fixed sill member 11 is provided with a recess or opening 23 adapted to engage a flange portion 24. The opening 23 is normally a downwardly diverging opening.

The extension sill portion 18 has an upwardly extending flange 24 on 5 an edge. The flange 24 extends upwardly substantially perpendicularly to the sill extension member 18 to engage with the downwardly diverging opening 23 on the adjacent fixed sill member 11.

The sill extension members 18 are provided with the flange portion 24 at or adjacent one side edge and a downwardly diverging opening 23 similar to that 10 provided on the fixed sill member 11, at or adjacent an opposite side edge to allow the mounting of further extension portions 17 thereto.

The extendable mounting system according to the present invention can be used in association with any slidable barrier element such as wardrobe doors, internal sliding partitions, privacy screens, gates or the like. However, the system will 15 typically be used in situations where the opening is surrounded by an accessible area capable of supporting the extension portions where added to the system. For this reason, the system is particularly well suited for use in sliding door systems such as wardrobe doors.

The system of the present invention is particularly useful for internal, 20 non-security doors such as wardrobes that are already provided with an opening of particular dimensions between the floor and the ceiling. One or more (typically a number of) barrier elements are generally provided in the slidable barrier system.

The barrier element will typically slide on guides, runners, bearings, or wheels. These may be mounted for rotation parallel to the barrier member or 25 perpendicular thereto to maintain spacing. A typical example used in a conventional barrier member system is a wheel which rests in a groove or channel in the sill and/or head member and supports the slidable barrier element.

Further, in conventional barrier member systems, the barrier elements normally rest on the sill member and are restricted to longitudinal movement only, by 30 the configuration of the head member. In this specification, the longitudinal direction is in relation to the head or sill member and toward one of the side jamb members. The lateral direction refers to a direction perpendicular to the plane of the opening.

In the present specification and claims (if any), the word "comprising" and its derivatives including "comprises" and "comprise" include each of the stated integers but does not exclude the inclusion of one or more further integers.

Reference throughout this specification to "one embodiment" or "an embodiment" means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment of the present invention. Thus, the appearance of the phrases "in one embodiment" or "in an embodiment" in various places throughout this specification are not necessarily all referring to the same embodiment. Furthermore, the particular features, structures, or characteristics may be combined in any suitable manner in one or more combinations.

In compliance with the statute, the invention has been described in language more or less specific to structural or methodical features. It is to be understood that the invention is not limited to specific features shown or described since the means herein described comprises preferred forms of putting the invention into effect. The invention is, therefore, claimed in any of its forms or modifications within the proper scope of the appended claims (if any) appropriately interpreted by those skilled in the art. 14

Claims (15)

Claims:

1. An extendable mounting system for a slidable barrier, the extendable mounting system including a. at least one track member each having at least one opening therein, 5 b. at least one removably attachable track extension portion and c. mounting means to removably attach the at least one track extension portion relative to the at least one track member laterally of the at least one track member to increase the number of track openings available for use in the system. 10

2. An extendable mounting system for a slidable barrier according to claim 1, wherein the slidable barrier is used to cover an opening and wherein at least one head track member is provided located at an upper side of the opening and at least one sill track member is provided located at a lower side of the opening, with at least one removeably attachable head track extension member and at 15 least one removeably attachable sill track extension member.

3. An extendable mounting system for a slidable barrier according to claim 2, wherein each of the head and sill track members also include one or more attachment assemblies to mount the members relative to the opening to be covered by the slidable barrier. 20

4. An extendable mounting system for a slidable barrier according to claim 2 or claim 3, including more than one of each head and sill track member, longitudinally aligned to span the opening.

5. An extendable mounting system for a slidable barrier according to claim 4, wherein the members are provided with at least one attachment portion to secure 25 the head track members relative to one another and the sill track members relative to one another.

6. An extendable mounting system for a slidable barrier according to any one of claims 2 to 5, wherein each head track member includes at least one section of a straight channel having a pair of side walls that extend substantially at right 30 angles from a base wall to form aligned flat flanges and defining a channel therebetween to accommodate a carriage of the sliding barrier travelling therebetween. 15

7. An extendable mounting system for a slidable barrier according to claim 6, wherein each head track member includes a pair of channels which are oriented parallel to one another defined by three spaced apart side walls that extend substantially at right angles from a base wall, the middle wall of the three walls 5 separating the pair of channels.

8. An extendable mounting system for a slidable barrier according to claim 3, wherein the attachment assemblies provided are a plurality of openings through a base wall through which fasteners are inserted to fix the members to the surrounds of the opening. 10

9. An extendable mounting system for a slidable barrier according to any one of claims 2 to 8, wherein the sill track member is provided as a guide to support the slidable barrier element.

10. An extendable mounting system for a slidable barrier according to claim 9, wherein at least one guide track is provided in the sill track member to assist 15 with alignment of the slidable barrier.

11. An extendable mounting system for a slidable barrier according to claim 9, wherein each guide track is a longitudinally extending recess or dip.

12. An extendable mounting system for a slidable barrier according to claim 9, wherein each guide track is a raised ridge or rail. 20

13. An extendable mounting system for a slidable barrier according to any one of claims 2 to 12 wherein track extension portions are provided for both the head track member and the sill track member to maintain the symmetry of the extendable mounting system.

14. An extendable mounting system for a slidable barrier according to any one of 25 claims 2 to 13 wherein each respective head and sill extension portion is similar in configuration to a single track from the respective head or sill track member.

15. An extendable mounting system for a slidable barrier according to any one of claims 2 to 12 wherein the head extension portion includes a side wall that extends substantially at right angles from a base wall to form an L-shaped 30 member attachable to the head track member to define a channel adapted to receive a slidable barrier element. 16 17. 5 18. 10 19. 15 20. 20 25 22. An extendable mounting system for a slidable barrier according to any one of the preceding claims wherein a track extension portion is mounted to a track extension portion which is attached to a track member. An extendable mounting system for a slidable barrier according to any one of the preceding claims wherein the mounting means is a multi-part means and includes a portion provided on each track member and extension portion each part of the multi-part mounting means engaging the other of the parts to fix the extension portion relative to the track member. An extendable mounting system for a slidable barrier according to any one of claims 2 to 17 wherein the mounting means located at an upper side of the opening includes a recess provided on one of the head track member or the head extension portion adapted to engage a flange portion provided on the other of the head track member or head extension portion. An extendable mounting system for a slidable barrier according to claim 18 wherein the head extension portion is provided with a further mounting means to allow the mounting of further head extension portions thereto. An extendable mounting system for a slidable barrier according to any one of claims 2 to 19 wherein the mounting means located at a lower side of the opening includes a recess provided on one of the sill track member or the sill extension portion adapted to engage a flange portion provided on the other of the sill track member or sill extension portion. An extendable mounting system for a slidable barrier according to claim 20 wherein the sill extension portion is provided with a further mounting means to allow the mounting of further sill extension portions thereto. An extendable mounting system for a slidable barrier substantially as described herein with reference to the accompanying drawings. 17 Abstract An extendable mounting system for a slidable barrier, the extendable mounting system including at least one track member each having at least one opening therein, at least one removably attachable track extension portion and mounting means to removably attach the at least one track extension portion relative to the at least one track member to increase the number of openings available for use in the system.