Patent Description:
In the specification, the term "comprising" shall be understood to have a broad meaning similar to the term "including" and will be understood to imply the inclusion of a stated integer or step or group of integers or steps but not the exclusion of any other integer or step or group of integers or steps. This definition also applies to variations on the term "comprising" such as "comprise" and "comprises".

It is known to provide retractable flexible screens which can extend across openings in building structures, such as doors and windows. Some screens, such as those for eliminating or reducing passage of insects, are primarily functional when the associated door or window opening is open. Other types of screens, such as those for eliminating or reducing passage of light, may be used with great utility whether the associated door or window opening is open or closed. Some screens may serve a dual purpose: for example, a screen which is primarily an insect screen may also moderate passage of light and may therefore be useful in its extended position whether the associated door or window opening is open or closed.

In some screen arrangements, for example, screen arrangements for bi-fold or stacking doors, the screen extends and retracts horizontally. It is often desirable to provide a horizontally opening screen capable of extending across an opening that is significantly wider than a standard doorway. For example, bi-fold doors, stacking doors and French doors are often used in conjunction with relatively wide openings.

One type of retractable screen provides a roller to which a first edge region of a flexible screen material is attached and onto which the flexible screen material is wound so that the screen material can be extended from, and retracted back onto, the roller in a direction perpendicular to the axis of the roller and the first edge region of the screen.

The roller is typically fixed in place at the top of a vertically opening screen or at the side of a horizontally opening screen.

The roller may be biased, for example, by a recoil spring, to bias the screen to its retracted position.

The edges of the screen material perpendicular to the first edge region may be constrained in guide tracks. This can assist in avoiding gaps between these edges and the structure defining the opening. For a horizontally opening screen arrangement, upper and lower guide tracks, which are opposed and substantially parallel, may be provided. For a vertically opening screen arrangement, left- and right-side guide tracks which are opposed and substantially parallel, may be provided.

The edge of the screen material opposite the first edge region may be attached to a moveable handle post or draw bar (referred to herein as a 'draw bar') that is moveable between a position closer to the roller, corresponding to a retracted or open configuration of the screen, and a position further from the roller, corresponding to an extended or closed configuration of the screen.

Respective opposed ends of the draw bar may operatively engage with the respective opposed guide tracks so that the guide tracks can guide movement of the draw bar between open and closed positions.

In some situations, it is desirable to position the screen so that it is partially, but not completely closed, that is, to have the screen material extending across part, but not all of the opening. This can be achieved by positioning the draw bar at a desired intermediate position, between the two extremes of its range of movement.

It will be appreciated that the recoil spring of the roller will pull the screen and draw bar to the fully open position of the screen in the absence of some restraining force that prevents retraction. Thus to enable the screen to be positioned, and then stay, partially closed, some mechanism to enable the draw bar to be retained at a desired intermediate position may be required.

One way of allowing the draw bar to be retained at a desired intermediate position is to provide a frictional force between the draw bar and the guide tracks. An example of a draw bar according to the prior art is described in <CIT>, which publication discloses a curtain fixture for a window comprising a bottom bar, blocks near the end of the bar and members supported by the blocks.

The present applicant's earlier application, <CIT> describes a vertically oriented draw bar having upper and lower brake arrangements. The present applicant's earlier application, <CIT>, describes a horizontally oriented draw bar having brake arrangements at each end. Each brake arrangement includes a brake with a shank that is slidingly engaged in a passage of a brake support, and is forced axially in a direction towards the respective guide track, by one or more springs within the draw bar. The brake thus engages the guide track to provide a braking force. The brakes can be moved away from the guide tracks by operation of a handle, the applied force acting against the springs to withdraw the brakes in the axial direction of the draw bar, away from the guide tracks, remove the braking force and allow convenient movement of the draw bar.

However, this brake arrangement has been found, at least sometimes, to provide inadequate braking force to prevent undesired movement of the draw bar in the retraction direction due to the retraction force applied by the biased roller.

Accordingly, it has been discerned that there is a need for an improved or at least alternative means of controlling the movement of a draw bar.

The reference to prior art or other background in this specification is not, and should not be taken as, an acknowledgment or any form of suggestion that the referenced prior art or other background forms part of the common general knowledge in Australia or in any other country.

According to a first aspect of the present disclosure, there is provided a draw bar for a retractable screen arrangement in which a screen material is extensible across an opening by movement of the draw bar in an extension direction in order to screen or partially screen the opening, and in which the screen material is retractable by movement of the draw bar in a retraction direction, to reduce occlusion of the opening by the screen material and in which the screen arrangement applies a retraction force, in the retraction direction, to the screen material to assist retraction of the screen material;
the draw bar comprising:
a brake arrangement for providing a braking force between the draw bar and a bearing surface of a track which in use guides the draw bar, to resist relative movement of the brake arrangement and the bearing surface in at least one direction, the brake arrangement comprising:.

The force-increasing arrangement according to the invention is configured to increase the force with which the friction surface engages the bearing surface by converting at least some of a frictional force applied between the friction surface and the bearing surface into additional contact pressure force applied to the brake member to increase contact pressure between the friction surface and the bearing surface.

In an embodiment, increasing the force with which the friction surface engages the bearing surface corresponds to increasing the force with which the friction surface is forced onto the bearing surface.

The force-increasing arrangement comprises a forcing part having a first region connected to the brake member support, a second region connected to the brake member, and an intermediate region for transmitting force between the first region and the second region.

In an embodiment, at least part of the forcing part is angled relative to the extension direction.

In an embodiment, at least part of the forcing part is angled relative to the extension direction, so that when a frictional force between the bearing surface and the friction member is applied to the forcing part in the extension direction, the forcing part provides a reaction force which forces the friction surface onto the bearing surface.

In an embodiment, at least part of the forcing part is angled relative to the extension direction, so that when a frictional force between the bearing surface and the friction member is applied to the forcing part in the extension direction, the forcing part provides a reaction force with a component directed towards the bearing surface.

In an embodiment, the forcing part comprises a brake member coupling which couples the brake member to the brake member support so that movement of at least the friction surface of the brake member relative to the brake member support is constrained by the brake member coupling to movement which has a component in the extension-retraction direction and a component towards or away from the bearing surface.

In an embodiment, the forcing part comprises a brake member coupling which couples the brake member to the brake member support so that movement of at least the friction surface of the brake member relative to the brake member support is constrained by the brake member coupling to movement which has a component in an axial direction of the brake member support, and a component in perpendicular to the axial direction of the brake member support.

In an embodiment, the forcing part comprises a brake member coupling which couples the brake member to the brake member support so that movement of at least the friction surface of the brake member relative to the brake member support is constrained by the brake member coupling to movement which follows a curved path.

In an embodiment, the forcing part comprises a brake member coupling which couples the brake member to the brake member support so that movement of at least the friction surface of the brake member relative to the brake member support is constrained by the brake member coupling to movement which follows a substantially arcuate path.

In an embodiment, the brake member coupling comprises at least one link member.

In an embodiment not encompassed by the wording of the claims, the at least one link member is operatively coupled to the brake member and to the brake member support.

In an embodiment, the at least one link member is pivotably coupled to at least one of the brake member and to the brake member support.

In an embodiment, the at least one link member is pivotably coupled to the brake member and to the brake member support.

In an embodiment, the at least one link member defines a substantially fixed distance between a part of the brake member and a part of the brake member support.

In an embodiment, the at least one link member defines a substantially arcuate path, relative to a part of the brake support member, along which movement of a part of the brake member is constrained.

In an embodiment, the at least one link member defines a substantially arcuate path, relative to a part of the brake support member, along which movement of a connection part of the brake member is constrained.

In an embodiment, the connection part of the brake member is adjacent the friction surface.

In an embodiment, the connection part of the brake member is a first one of a projection or an aperture, which in use is connected to the other of a projection or an aperture provided on the link member.

In an embodiment, the brake member includes an actuating part.

In an embodiment, the actuation part is part of the brake member.

In an embodiment, the actuating part extends away from the friction surface and is controllable by a user to move the friction surface away from the bearing surface, against the force applied by the biasing arrangement.

In an embodiment, movement of the actuating part is guided by the brake member support.

In an embodiment, movement of the actuating part is guided by the actuating part being moveably engaged in a passage provided in the brake member support.

In a non-claimed embodiment, the biasing arrangement comprises a resilient member arranged to provide a bias force between the brake member support and the brake member.

In an embodiment not encompassed by the wording of the claims, the resilient member comprises a spring.

In an embodiment not encompassed by the wording of the claims, the resilient member comprises a helical spring maintained in a compressed arrangement, which provides the bias force in its extension direction.

In an embodiment not encompassed by the wording of the claims, the resilient member is oriented in a direction which extends from a part of the brake member support towards the friction surface.

In an embodiment not encompassed by the wording of the claims, a first part of the resilient member applies a force against a part of the brake member support, and a second part of the resilient member applies a force against a part of the brake member, so as to apply the bias force by forcing apart said part of the brake member support and said part of the brake member.

In an embodiment, the at least one link member is offset laterally from the friction surface.

In an embodiment, the brake assembly provides at least one link member towards each lateral side of the brake assembly.

In an embodiment, the brake assembly provides at least one link member on each lateral side of the friction surface.

In an embodiment, the brake arrangement further comprises a latch arrangement, for engagement with a catch provided adjacent the bearing surface.

In an embodiment, the latch arrangement comprises a latch member moveable by the brake member from a latching position to a disengaging position.

In an embodiment, an action by a user which moves the friction surface into a withdrawn position also moves the latch into the disengaging position.

In an embodiment not encompassed by the wording of the claims, the brake arrangement includes a base region defining a cavity which, in use, retains at least part of a rail portion of a guide track therein.

In an embodiment not encompassed by the wording of the claims, the cavity has a wider main part, and a narrower entrance part, so that the cavity is adapted to retain therein a guide rail which has a wider terminal region which is too wide to pass through the entrance part of the cavity, and a narrower region connected to the terminal region, the narrower region being adapted to be slideably retained in the entrance part of the cavity.

In an embodiment not encompassed by the wording of the claims, the cavity is adapted to retain therein the guide rail therein so that even in the event of a large force being applied to the bearing surface by the brake member, the brake support is not substantially forced away from the guide rail by said large force.

In an embodiment not encompassed by the wording of the claims, application of a large force being applied to the bearing surface by the brake member substantially clamps the guide rail between the friction surface and a part of the base region at or adjacent the narrower entrance part of the cavity.

According to a second aspect of the present disclosure not encompassed by the wording of the claims, there is provided a draw bar for a retractable screen arrangement in which a screen material is extensible across an opening by movement of the draw bar in an extension direction in order to screen or partially screen the opening, and in which the screen material is retractable by movement of the draw bar in a retraction direction, to reduce occlusion of the opening by the screen material and in which the screen arrangement applies a retraction force, in the retraction direction, to the screen material to assist retraction of the screen material;
the draw bar comprising:
a brake arrangement for providing a braking force between the draw bar and a bearing surface of a track which in use guides the draw bar, to resist relative movement of the brake arrangement and the bearing surface in at least one direction, the brake arrangement comprising:.

In an embodiment not encompassed by the wording of the claims, the forcing arrangement further comprises a biasing arrangement for biasing the friction surface towards the bearing surface.

In an embodiment not encompassed by the wording of the claims, the biasing arrangement operates independent of whether the force-increasing arrangement is actively increasing the force with which the friction surface engages the bearing surface by converting at least some of a frictional force applied between the friction surface and the bearing surface into additional contact pressure force applied to the brake member.

It will be appreciated that characteristics and features described above in relation to embodiments related to the first aspect may also be incorporated into the draw bar of the second aspect not encompassed by the wording of the claims.

According to a third aspect of the present disclosure not encompassed by the wording of the claims, there is provided a brake arrangement for a draw bar of a retractable screen arrangement in which a screen material is extensible across an opening by movement of the draw bar in an extension direction in order to screen or partially screen the opening, and in which the screen material is retractable by movement of the draw bar in a retraction direction, to reduce occlusion of the opening by the screen material and in which the screen arrangement applies a retraction force, in the retraction direction, to the screen material to assist retraction of the screen material;
the brake arrangement being for providing a braking force between the draw bar and a bearing surface of a track which in use guides the draw bar, to resist relative movement of the brake arrangement and the bearing surface in at least one direction, the brake arrangement comprising:.

It will be appreciated that characteristics and features described above in relation to embodiments related to the first aspect may also be incorporated into the brake arrangement of the third aspect of the present disclosure not encompassed by the wording of the claims.

According to a fourth aspect of the present disclosure not encompassed by the wording of the claims, there is provided a brake arrangement for a draw bar of a retractable screen arrangement in which a screen material is extensible across an opening by movement of the draw bar in an extension direction in order to screen or partially screen the opening, and in which the screen material is retractable by movement of the draw bar in a retraction direction, to reduce occlusion of the opening by the screen material and in which the screen arrangement applies a retraction force, in the retraction direction, to the screen material to assist retraction of the screen material;
the a brake arrangement being for providing a braking force between the draw bar and a bearing surface of a track which in use guides the draw bar, to resist relative movement of the brake arrangement and the bearing surface in at least one direction, the brake arrangement comprising:.

It will be appreciated that characteristics and features described above in relation to embodiments related to the first and/or second, non-claimed, aspects may also be incorporated into brake arrangement of the fourth aspect of the present disclosure not encompassed by the wording of the claims.

According to a fifth aspect of the present disclosure not encompassed by the wording of the claims, there is provided a brake arrangement for providing a braking force between a first element, to which the brake arrangement is attached in use, and a second element which provides a bearing surface, the braking force being to resist relative movement of the brake arrangement and the bearing surface in at least one direction by providing a braking force between the first element and the bearing surface, the brake arrangement comprising:.

It will be appreciated that characteristics and features described above in relation to embodiments related to the first aspect may also be incorporated into the brake arrangement of the fifth aspect of the present disclosure not encompassed by the wording of the claims.

According to a sixth aspect of the present disclosure not encompassed by the wording of the claims, there is provided a brake arrangement for providing a braking force between a first element, to which the brake arrangement is attached in use, and a second element which provides a bearing surface, the braking force being to resist relative movement of the brake arrangement and the bearing surface in at least one direction by providing a braking force between the first element and the bearing surface, the brake arrangement comprising:.

It will be appreciated that characteristics and features described above in relation to embodiments related to the first and/or second, non-claimed, aspects may also be incorporated into brake arrangement of the sixth aspect of the present disclosure not encompassed by the wording of the claims.

Embodiments will be described below, in detail, with reference to accompanying drawings. The primary purpose of this detailed description is to instruct persons having an interest in the subject matter of the invention how to carry the invention into practical effect. However, it is to be clearly understood that the specific nature of this detailed description. In the accompanying diagrammatic drawings:.

With reference to the accompanying drawings, embodiments of a brake arrangement will be described. The brake arrangement is described with particular reference to use in a draw bar used for retaining a forward edge of a flexible screen, so that the screen can be drawn across an opening to extend or retract the screen, but it will be appreciated that embodiments of the disclosed brake arrangement could be used for other purposes and in conjunction with other types of apparatus.

<FIG> illustrates schematically, and by way of example, a screen arrangement <NUM>, comprising a vertically orientated roller cover <NUM> which houses a vertically orientated roller (not shown) to which a first vertical edge (not shown) of a flexible screen <NUM> is attached. The flexible screen <NUM> is wound on the roller so that the screen <NUM> is extensible across an opening <NUM>, and retractable onto the roller, as indicated by a double headed arrow <NUM>. The roller cover <NUM>, or a frame part (not shown) associated therewith, provides a first upright frame part of the screen arrangement <NUM>. The screen arrangement <NUM> further comprises an upper guide track <NUM> which retains an upper edge of the flexible screen <NUM>, a bottom guide track <NUM> which retains a lower edge of the flexible screen <NUM>, and a second upright frame part <NUM>. The upper and bottom guide tracks <NUM>, <NUM> extend between the roller cover <NUM> and the second upright frame part <NUM>. The screen arrangement <NUM> further comprises a draw bar <NUM> which is retained between the upper and bottom guide tracks <NUM>, <NUM> and is moveable substantially between the roller cover <NUM> and the second upright frame part <NUM>. The draw bar <NUM> retains a second vertical edge of the flexible screen <NUM> opposed to the first vertical edge, so that movement of the draw bar extends or retracts the flexible screen <NUM>.

The draw bar <NUM> may be provided with brake assemblies <NUM> at its top and bottom to enable the draw bar <NUM> to be retained at a desired position intermediate the roller cover <NUM> and the second upright frame part <NUM> corresponding to a partially closed position of the screen <NUM>.

<FIG> is an exploded perspective view, and <FIG> is an assembled view, of a brake assembly, generally designated <NUM>, suitable for use in the draw bar <NUM> of the type illustrated in <FIG>.

The brake assembly <NUM> comprises a brake assembly housing <NUM>, and a brake member <NUM>, which is moveably supported by the brake assembly housing <NUM>. The brake member <NUM> includes a brake pad <NUM> which provides a friction surface <NUM> for engaging a bearing surface, for example a bearing surface (e.g. <NUM>, <NUM> in <FIG>) of the bottom guide track <NUM>.

Identical brake assemblies can be used at the top and bottom of the draw bar <NUM> (or at the respective ends of a horizontally extending draw bar of a vertically extensible screen arrangement). However, for ease of description and understanding, the following detailed description of the brake assembly <NUM> is with reference to its use at the bottom of the draw bar <NUM>.

It will be appreciated that the draw bar <NUM> can be moved in an extension direction of the screen and in a retraction direction of the screen, as desired. The brake assembly <NUM> and housing <NUM> are may be regarded as having a front or forward side which is the leading side when the draw bar is moved in the extension direction of the screen, and a rear side, which is the following side when the draw bar is moved in the extension direction (and is, of course the leading side when the draw bar is moved in the retraction direction of the screen). Thus a front-rear direction is substantially perpendicular to the direction of elongation of the draw bar, and corresponds to the direction of movement of the draw bar when drawing, or extending, the screen. The front-rear direction also corresponds to the direction of movement of the brake assembly <NUM> relative to the bearing surface, and the direction in which frictional forces between the friction surface <NUM> and the bearing surface may be considered to be directed.

Thus the brake member <NUM> can be moved substantially in the direction of elongation of the draw bar, which may also be regarded as an axial direction of the brake assembly <NUM>, and of the housing <NUM>, in order to engage or disengage the brake. The axial direction is also, in use, a direction substantially perpendicular, or normal, to the bearing surface. The axial direction substantially towards the bearing surface may be referred to herein as the first axial direction. The first axial direction is downwards in accompanying drawings, which illustrate the brake assembly orientated as if for use at the bottom of a draw bar, but would be upwards if the brake assembly <NUM> were oriented for use at the top of a draw bar. The axial direction substantially away from the bearing surface may be referred to herein as the second axial direction.

The brake assembly <NUM> further comprises a spring <NUM> for providing a bias force between the housing <NUM> and the brake member <NUM>. The spring <NUM> has a first end <NUM>, which, in use, is closer to, and applies a force (generally in the first axial direction) towards, the friction surface <NUM>, and a second end <NUM> which, in use, is further from the bearing surface <NUM>. The second end <NUM>, in use, may be regarded as applying a force against the housing <NUM> in a direction oriented away from the bearing surface <NUM> (generally in the second axial direction). The spring <NUM> is, in use, maintained under compression so that it applies a bias force between the housing <NUM> and the friction surface <NUM>. In use, the bias force provided by the spring <NUM> forces the friction surface <NUM> towards, and into engagement with, a bearing surface, for example, a bearing surface of the bottom guide track <NUM>.

It will be appreciated that forced engagement of the friction surface <NUM> against the bearing surface (along with suitable choices of materials) results in a frictional force between the friction surface <NUM> and the bearing surface, which can be utilised as a braking force to retard or prevent undesired movement of the draw bar.

Thus, in the illustrated embodiment, the engagement of the friction surface <NUM> against the bearing surface resulting from the bias force applied by the spring <NUM> can provide a braking force to counteract the force applied to a screen and draw bar in the retraction direction by a biased roller. The braking force can be useful to retard or prevent undesired movement of the draw bar in the retraction direction and can often be sufficient to allow the screen to be maintained in a partially open position.

The brake member can be withdrawn away from the bearing surface to remove the braking force and allow the draw bar to be easily moved, when desired. In the illustrated embodiment, the brake member <NUM> can be manually forced against the bias force applied by the spring <NUM> (compressing the spring, as will be described in more detail in due course). Thus the brake member <NUM> can be moved in the direction of elongation of the draw bar, which may also be regarded as an axial direction of the housing <NUM> in order to engage or disengage the brake. The direction of elongation of the draw bar is also, in use, a direction perpendicular, or normal, to the bearing surface.

While the braking force resulting from the friction surface <NUM> being forced against the bearing surface by the bias force applied by the spring <NUM> can often be sufficient to counteract the retraction force applied by a biased roller, it has been found that such a braking force is sometimes insufficient. The illustrated embodiment provides a force-increasing arrangement which can increase the force with which the friction surface <NUM> of the brake pad <NUM> engages the bearing surface.

It will be appreciated that in the illustrated embodiment, in addition to being moveable in the axial direction of the housing <NUM>, the brake member <NUM> also has some freedom to move, relative to the housing <NUM>, in the front-rear direction, which is perpendicular to the direction of elongation of the draw bar, and which corresponds to the direction of movement of the draw bar corresponding to drawing and retracting the screen. The front-rear direction also corresponds to the direction of movement of the brake assembly <NUM> relative to the bearing surface and the direction in which frictional forces between the friction surface <NUM> and the bearing surface may be considered to be directed.

The brake assembly <NUM> further comprises at least one link member <NUM>, which in use provides part of a force-increasing arrangement which can increase the force with which the friction surface <NUM> of the brake pad <NUM> engages the bearing surface. In use, the increased engagement force increases the frictional force between the friction surface <NUM> and the bearing surface, thus providing more effective braking (at least in some circumstances) than would be provided if the engagement force were solely, or substantially solely, the bias force provided by the spring <NUM>. The force-increasing arrangement converts at least some of a frictional force applied between the friction surface <NUM> and the bearing surface into additional contact pressure force applied to the brake member <NUM>, thus increasing the engagement force, or contact pressure, between the friction surface <NUM> and the bearing surface. The increased engagement force, or contact pressure results in increased frictional force between the friction surface <NUM> and the bearing surface, thus providing more effective braking.

In the illustrated embodiment, the at least one link member <NUM> may be regarded as constraining movement of the brake member <NUM> relative to the housing <NUM> to a substantially predetermined path (as will be described in more detail hereafter). The substantially predetermined path has a direction component in the direction normal to the bearing surface (the axial direction of the housing and/or the direction of elongation of the draw bar) and a direction component in the direction of the frictional force which in use occurs between the friction surface <NUM> and the bearing surface.

The predetermined path is arranged and oriented so that a frictional force between the friction surface <NUM> and the bearing surface (e.g. <NUM>, <NUM>), can force and/or move the brake member <NUM> along part of the predetermined path, and so that this forcing and/or movement along the predetermined path forces and/or moves the brake member <NUM> towards the bearing surface. Thus it will be understood that the force-increasing arrangement can be regarded as converting at least some of the frictional force, applied in a direction perpendicular to the axis of elongation of the draw bar <NUM>, into a force with a component perpendicular to the axis of elongation of the draw bar, thus increasing the engagement force, or contact pressure, between the friction surface <NUM> and the bearing surface.

The predetermined path provided in the illustrated embodiment will be described further, with particular reference to <FIG>, <FIG> and <FIG>, in due course.

As illustrated in <FIG> and <FIG>, and also <FIG>, the housing <NUM> comprises first and second side walls <NUM>, <NUM> which provide a space therebetween for accommodating at least part of the brake member <NUM>.

The housing may be considered as having an axial direction, corresponding to a direction which is, in use directed away from the bearing surface and perpendicular to the direction of relative movement of the braking arrangement and the bearing surface. In the illustrated embodiment, this axial direction corresponds to the direction of elongation of the draw bar.

At a part of the housing which is, in use, distal from the bearing surface, the side walls <NUM>, <NUM> are connected by a first laterally extending wall <NUM> which provides a passage <NUM>, through which an actuating part of the brake arrangement can pass. The actuating part may be an elongate stem <NUM> of a brake member <NUM>, as will be described in due course. The passage <NUM> allows movement of the actuating part in the axial direction of the brake assembly, and also provides sufficient clearance to allow some change in orientation of the actuating part, as will be described in due course.

At a part of the housing which is, in use, closer to the bearing surface, the side walls <NUM>, <NUM> are connected by a base portion <NUM> of the housing <NUM>. The base portion <NUM> provides first-side and second-side portions <NUM>, <NUM> and front and rear portions <NUM>, <NUM>, to provide (in the illustrated embodiment) the base portion <NUM> with an external shape which is substantially rectangular in end view (or transverse cross section).

A region of the base portion <NUM> which is further from the first laterally extending wall <NUM> is adapted, in use to provide an end of a draw bar and to engage a guide track of which the bearing surface forms a part.

The base portion <NUM> provides a passage <NUM> (see, for example, <FIG>) for allowing brake member <NUM> to extend therethrough, so that the friction surface <NUM> can contact the bearing surface.

The rear portion <NUM> of the base portion <NUM> includes a laterally central region defining a retaining channel portion <NUM> for retaining part of the leading edge of a screen material therein.

In the illustrated embodiment, the housing <NUM> provides an internal wall portion <NUM> which extends between the side walls <NUM>, <NUM> and provides a passage <NUM>, between the internal wall portion <NUM> and the front portion <NUM> of the base portion <NUM>. The passage <NUM> extends substantially in the axial direction of the housing <NUM>, and in use, accommodates part of a latch member <NUM>, and guides movement of the latch member <NUM> substantially in the axial direction of the brake assembly. The latch member <NUM> is provided to enable the draw bar to be retained by a catch provided on or adjacent the guide track, as will be described in due course.

The side walls <NUM>, <NUM> are also connected by a rear wall <NUM> of the housing <NUM>.

The housing <NUM> also provides at least one connection formation for connection of the link members <NUM> thereto. In the illustrated embodiment, the least one connection formation comprises a through bore <NUM>, which extends through the internal wall portion <NUM>.

The housing <NUM> also provides a number of fixing holes <NUM> which extend through the base portion <NUM>, adjacent the corners of the rectangular cross sectional shape thereof, to facilitate attachment of the brake assembly <NUM> to one or more other parts of a draw bar.

The brake member <NUM> provides the brake pad <NUM>, and a brake shoe <NUM> or holding portion, for holding the brake pad <NUM>. The brake shoe <NUM> provides a transverse wall portion 53A, and side wall portions <NUM>, <NUM> which extend along lateral sides of the brake pad <NUM> to enhance retention of the brake pad by the brake shoe <NUM>.

Extending away from the brake shoe <NUM>, and directed away from the friction surface, there is provided an actuating member via which the brake shoe <NUM> can be moved. In the illustrated embodiment, the actuating member is in the form of a rod or stem <NUM>, which forms part of the brake member <NUM>. In this embodiment, the stem <NUM> provides a connection formation, in the illustrated embodiment in the form of an aperture <NUM>, for connection to an operating mechanism, such as a handle, which can be operated to effect withdrawal of the brake pad <NUM> from the bearing surface. As foreshadowed above, and as can be seen in, for example, <FIG>, in use the stem <NUM> extends through the passage <NUM> in the first laterally extending wall <NUM>, and the aperture <NUM> is on part of the stem <NUM> which projects past the first laterally extending wall <NUM>. So that it may be regarded as being external to the housing <NUM>.

The brake member <NUM>, further provides latch member engagement parts <NUM>, <NUM> which engage the latch member <NUM> so that withdrawal of the brake pad <NUM> away from the bearing surface by movement of the brake member <NUM> also effects movement of the latch member <NUM>. This can allow or assist in disengaging the latch member <NUM> from a catch provided on or adjacent the guide track, without requiring a different operating mechanism.

The brake member <NUM> further provides one or more connection formations for connection of the link members <NUM>. In the illustrated embodiment, the connection formations are in the form of stub axles <NUM>, <NUM>, which may be provided projecting laterally outwardly from the side wall portions <NUM>, <NUM> of the brake shoe <NUM>. In the illustrated embodiment, the one or more connection formations are provided an in use front part of the brake member <NUM>, for example, adjacent front edges of the side wall portions <NUM>, <NUM> of the brake shoe <NUM>. In the illustrated embodiment the one or more connection formations are substantially coaxial.

In the illustrated embodiment, the brake assembly <NUM> provides first and second link members <NUM>, 90A, one on either lateral side of the brake assembly <NUM>. It will be appreciated that the form and function of the two link members <NUM>, 90A generally correspond, with the second link member 90A being a mirror image of the first link member <NUM>, so that the form and function if the first link member <NUM>, described below, applies mutatis mutandis to the second link member 90A.

The first link member <NUM> is in the form of a substantially rigid member that is somewhat elongate and has a first end region <NUM> and a second end region <NUM>.

The first end region <NUM> provides a first connection formation <NUM> for allowing pivotal connection to a connection formation provided on the brake member <NUM>. In this embodiment, the first connection formation <NUM> is in the form of a recess or aperture for connection to a stub axle <NUM> provided on the first side wall portion <NUM> of the brake shoe <NUM>.

The second end region <NUM> provides a second connection formation <NUM> for allowing pivotal connection to a connection formation provided on the housing <NUM>. In this embodiment, the second connection formation <NUM> is in the form of a recess or through aperture for connection to the through bore <NUM>, which extends through the internal wall portion <NUM> of the housing <NUM>. A pivot axle in the form of a connecting pin <NUM> is used to connect the second connection formation <NUM> to the through bore <NUM>, by extending through the second connection formation <NUM> of the first link member <NUM> and into the through bore <NUM>. It will be appreciated that in the illustrated embodiment, the connecting pin <NUM> extends through the second connection formation <NUM> of the first link member <NUM>, through the through bore <NUM> of the housing <NUM>, and through a second connection formation 94A of the second link member 90A to connect both the first and second link members <NUM>, 90A to the housing <NUM>. It should also be appreciated that the connecting pin <NUM> is supported along most of its length by its engagement in the through bore <NUM> which helps avoid undesirable bending of the connecting pin <NUM>.

The second end region <NUM> of the first link member <NUM> is provided with a boss, or spacing formation <NUM>, which engages the housing <NUM> and spaces the rest of the first link member laterally outwardly relative to the housing <NUM>. This can help avoid the brake shoe <NUM> interfering with movement of the first link member <NUM>, in use.

In use, the first and second link members <NUM>, 90A remain substantially mutually parallel. Provision of link members <NUM>, 90A on each lateral side of the housing assists in distributing forces laterally across the width of the brake arrangement and in avoiding undesirable torques on the components of the brake arrangement.

Provision of the first and second link members <NUM>, 90A, which each maintain a constant distance between a part of the housing (in the illustrated embodiment, the connection formation, through bore <NUM>) and a part of the brake member (in the illustrated embodiment, the connection formations, stub axles <NUM>, <NUM>) provides a predetermined path of movement for the brake member <NUM>, and particularly for the friction surface <NUM>, relative to the housing.

The predetermined path therefore, in this embodiment, corresponds to a path in which the connection formations <NUM>, <NUM> of the brake member <NUM> move in an arcuate path, centred substantially about the connection formations provided on the housing <NUM>, and the connecting pin <NUM>. This predetermined path is arranged and oriented so that a frictional force between the friction surface <NUM> and the bearing surface can force and/or move the friction surface <NUM> along part of the predetermined path, towards the bearing surface, thus increasing the braking force, as foreshadowed above.

<FIG> illustrates the brake assembly <NUM> with the brake member <NUM> substantially at its most extended position, that is, at one end of the predetermined path along which it can move.

<FIG> illustrates the brake assembly <NUM> with the brake member <NUM> substantially at its most withdrawn position, that is, at one the other of the predetermined path along which it can move.

<FIG> provide cross sectional views through the first link member so that the positions of the link member <NUM> can be clearly seen. <FIG> further include a broken-line double headed arrow, designated 'A', which illustrates schematically the predetermined path along which the brake member's movement is constrained. For convenience, the arrow A illustrates the path of the axis of the stub axles <NUM>, <NUM> and can be seen to extend beyond the actual range of movement, since it extends to the right and downwardly beyond the position of the stub axle <NUM> in <FIG>. It will be appreciated that the path of the axis of the stub axles corresponds substantially to the arcuate path of the first end of the link member <NUM>, but that the predetermined path of the brake member as a whole is more complex, as there is a rotational degree of freedom between the brake member <NUM> and the link member <NUM>, and a distal region of the stem <NUM> of the brake member <NUM> is constrained to slide through the passage <NUM>, but slightly changes orientation as it does so, as can be seen by comparison of <FIG>. The path of the friction surface <NUM> (at least the part of the friction surface closest to the axis of the stub axles) approximates the path of the axis of the stub axles, as the axis of the stub axles is close to the friction surface.

Further, it should be appreciated that, in use, when the friction surface <NUM> engages a bearing surface the abutment with the bearing surface will generally prevent the brake member <NUM> from reaching the position illustrated in <FIG>, but will cause it to be held in a position just offset from this fully extended position (as illustrated in, and described further with reference to, <FIG>). Frictional forces resulting from engagement of the friction surface with the bearing surface as a result of movement or forcing of the draw bar in the retraction direction of the screen, will force the brake member towards the fully extended position illustrated in <FIG>, thus forcing the friction surface against the bearing surface and increasing braking force.

As foreshadowed above, in the illustrated embodiment, the brake arrangement includes a latch member <NUM>. The latch member provides an actuating part <NUM> which is biased actuating part <NUM> which is engaged, in use by the engagement parts <NUM>, <NUM> so that an operation (e.g. by a user) which withdraws the brake pad <NUM> from the bearing surface can also be used to move the latch member in an axial direction of the housing <NUM> to disengage the latch member from a catch (as will be described in due course). The actuating part <NUM> also provides an aperture forming a passageway <NUM> for the stem <NUM> to pass through. Thus the actuating part <NUM> may be regarded as both extending around, and being supported by, part or parts of the brake member <NUM>.

The actuating part may be regarded as having a first-side surface <NUM> which is closer to, and faces generally towards, the friction surface <NUM>, and a second-side surface <NUM> which is further from, and faces generally away from, the friction surface <NUM>.

The latch member further provides a catch engaging part <NUM> which depends substantially perpendicular from the actuating part <NUM>. In use, the catch engaging part <NUM> is located in and guided by the passage <NUM>, described above, and has a terminal region <NUM> which can extend beyond the passage <NUM> to engage the catch.

The aperture forming the passageway <NUM> in the actuating part <NUM> is elongated in the front-rear direction of the brake assembly and provides a somewhat loose fit for the stem <NUM>, at least in the front-rear direction, allowing the stem <NUM> some freedom of movement in the front-rear direction despite the actuating part <NUM> of the catch member being constrained to move substantially in the axial direction of the brake assembly.

In the illustrated embodiment, the brake assembly <NUM> further includes a moveable seat <NUM> for retaining the first end <NUM> of the spring <NUM>. The moveable seat <NUM> extends around the stem <NUM> of the brake member <NUM>, the stem extending, in use, through a passageway <NUM> in the moveable seat <NUM>. The moveable seat has a first side <NUM> which faces towards, and is shaped to retain, the first end <NUM> of the spring <NUM>. The moveable seat has a second side <NUM> which engages the second-side surface <NUM> of the actuating part <NUM> of the latch member <NUM>.

In use, the moveable seat <NUM> is forced against the second-side surface <NUM> of the actuating part <NUM>, but can slide relative thereto, so that it can move relative to the latch member <NUM>, with the stem <NUM>, in the front-rear direction, while retaining engagement with the first end <NUM> of the spring <NUM>. This assists consistent application of the bias force by the spring <NUM> to the brake member <NUM> (and the latch member <NUM>) irrespective of the position and orientation of the brake member relative to the housing <NUM>. By way of illustration, <FIG> shows the moveable seat <NUM> positioned further towards the front of the brake assembly <NUM> (corresponding to a more extended position of the brake member <NUM>) and <FIG> shows the moveable seat <NUM> positioned further towards the rear of the brake assembly <NUM> (corresponding to a more withdrawn position of the brake member <NUM>).

<FIG> and <FIG>, also illustrate effectively that the side wall portions <NUM>, <NUM> of the brake shoe <NUM> extend beyond the friction surface <NUM> in the axial direction of the brake assembly <NUM>.

<FIG> is a perspective view of a bottom region of a draw bar, for example, the draw bar <NUM> of <FIG>, showing the brake assembly <NUM> incorporated into the bottom of the draw bar <NUM>, by attachment at the bottom of a draw bar main body <NUM> (of which only the bottom region is shown in <FIG>). It will be appreciated that the draw bar main body <NUM> is hollow, and that most of the brake assembly <NUM> is accommodated within an interior of the draw bar main body so that only part of the base portion <NUM> of the brake assembly <NUM> is visible in <FIG>.

<FIG> also shows a withdrawal member <NUM>, which may be, for example, a rod, cable or wire. The withdrawal member <NUM> extends along the hollow interior and is attached to the connection formation, aperture <NUM>, of the brake member <NUM> at one (e.g. a lower) end thereof, and to an operating mechanism, such as a handle, at the other (e.g. a higher) end thereof, to connect the operating mechanism to the brake member <NUM>. This allows operation of the operating mechanism (not shown) by a user to effect withdrawal of the brake pad <NUM> from the bearing surface.

<FIG> is a schematic transverse cross sectional view of the draw bar main body <NUM>.

The draw bar main body <NUM> may be regarded as having a front side wall <NUM> which, in use, is distal from a roller onto which the screen material can be wound and unwound, so that it provides a 'front' or leading wall of the draw bar when the draw bar is being moved to extend (close) the screen. The draw bar main body <NUM> may further be regarded as having a rear side wall <NUM> opposed to the front side wall <NUM>. The draw bar main body <NUM> further has first and second lateral side walls <NUM>, <NUM> of the draw bar main body <NUM>.

A formation defining a retaining channel <NUM> is provided in the rear side wall <NUM>. The retaining channel <NUM> is for retaining a leading edge of the material providing the flexible screen (e.g. flexible screen <NUM>, as shown in <FIG>).

The retaining channel <NUM> is provided substantially laterally centrally in relation to the draw bar main body <NUM>, and is also provided substantially laterally centrally in relation to the draw bar <NUM> as a whole. Further, in use, the retaining channel <NUM> aligns with, and is substantially continuous with, the retaining channel portion <NUM> of the base portion <NUM> of the housing <NUM>.

The draw bar main body <NUM> is generally rectangular in transverse cross sectional shape (as shown best in <FIG>) and provides an interior cavity <NUM>, which is also generally rectangular in transverse cross sectional shape.

As best shown in <FIG>, at each corner region, that is, in each region where a lateral side wall <NUM>, <NUM> meets the front side wall <NUM> or the rear side wall <NUM>, the draw bar main body <NUM> provides a fixing retaining formation <NUM>, adapted facilitate attachment of the brake arrangement <NUM> to the draw bar main body <NUM> by aligning with, and retain a fixing that passes through, a corresponding fixing hole <NUM> which extends through the base portion <NUM>.

The main body part <NUM> may be formed by extrusion, for example, of an aluminium or some other suitable metal or alloy. Alternatively, some other material, such as a suitable plastic, could be used.

The generally rectangular shape of the base portion <NUM> of the housing <NUM> of the brake assembly <NUM> allows the brake assembly <NUM> to fit to the hollow draw bar main body <NUM> to provide a generally continuous external shape, as shown, for example, in <FIG>. The transverse cross sectional dimensions of the parts of the brake assembly <NUM> other than the base region are equal to or smaller than the transverse cross sectional dimensions of the interior cavity <NUM> of the draw bar main body <NUM>, allowing these parts to be accommodated within the hollow interior of the draw bar main body <NUM>.

<FIG> is a schematic perspective view of a draw bar <NUM> in isolation, noting that identical brake assemblies <NUM>, 20A may be provided at the bottom and top of the draw bar <NUM>. The brake assemblies <NUM>, 20A may be regarded as being in the form of, or incorporated into, end caps of the draw bar <NUM>.

The draw bar <NUM> includes an operating mechanism, such as a handle arrangement <NUM> which can be used to withdraw the brake member <NUM>, against the bias force of the spring <NUM>, to disengage the friction surface <NUM> from the bearing surface. As foreshadowed above, in an embodiment, the operating mechanism is connected to the brake member <NUM> via withdrawal member <NUM>, which may be, for example, a rod, cable or wire, attached at one end region to the operating mechanism and at the other end region to the brake member <NUM>.

The handle arrangement <NUM> may be at an axially (for example, in use vertically) generally central part of the draw bar and a main body element, for example, corresponding to the main body part <NUM> may be provided on each side (for example, in use above and below) the handle arrangement <NUM>.

Any desired and appropriate the operating mechanism may be used. It is convenient to provide an operating mechanism which can disengage brake arrangements at both ends of the draw bar by a single action of a user. Two earlier patent publications describe examples of respective alternative brake release mechanisms which could be used, although of course other brake release mechanisms could be used if desired.

<CIT>, the entire disclosure of which is incorporated herein by reference, describes a brake release mechanism using a handle which can be rotated about an axis substantially perpendicular to the direction of elongation of the draw bar. See especially <FIG> of <CIT>, and the corresponding description.

The present applicant's earlier application, <CIT>, the entire disclosure of which is incorporated herein by reference, describes a brake release mechanism using a handle which can be rotated about an axis substantially parallel to the direction of elongation of the draw bar.

It will be appreciated that both of these brake release mechanisms allow release of the brake arrangements at both ends of the draw bar by a single action of a user. Further, both allow release of the brake arrangements from either lateral side of the draw bar.

<FIG> provides an enlarged front view of the bottommost region of the draw bar <NUM>, adjacent an example of a bottom track which may retain and guide the draw bar <NUM> in use, and which may provide the bearing surface for engagement by the friction surface <NUM>.

As shown in <FIG>, the base region <NUM> of the brake assembly <NUM> provides an engaging formation shaped to operatively engage a track element <NUM> of a guide track arrangement, generally designated <NUM>. In the illustrated embodiment, the engaging formation provides a shaped cavity <NUM> substantially at the end of the draw bar <NUM>.

In the embodiment illustrated in <FIG>, the guide track arrangement <NUM>, comprises the track element <NUM> and a separately formed elongate mounting element <NUM> to which the track element <NUM> is attached. The track element <NUM> is retained relative to the elongate mounting element <NUM> by a securing strip <NUM>.

The track element <NUM> provides a track portion <NUM> which provides an elongate guide cavity <NUM> for receiving an edge of a flexible screen. A guide cavity insert in the form of a track runner <NUM> is retained within the elongate guide cavity <NUM> to assist in retaining and guiding an edge of the screen.

The track portion <NUM>, in this embodiment, may be regarded as having first and second track regions <NUM>, <NUM> which are laterally adjacent but slightly spaced apart and shaped to define the elongate guide cavity <NUM> therebetween.

The first and second track regions <NUM>, <NUM> are both connected to a base region <NUM> of the track portion <NUM>. The base region <NUM> provides a base surface portion for engagement with the elongate mounting element <NUM>.

Each of the first and second track regions <NUM>, <NUM> has a laterally outwardly facing surface <NUM>, <NUM>, respectively, which faces generally laterally outwardly towards a lateral edge of the elongate track element <NUM>. In the illustrated embodiment, the laterally outwardly facing surfaces <NUM>, <NUM> are concave, so that the track portion <NUM> (formed by the first and second track regions <NUM>, <NUM>) is laterally wider closer to and further from the base region <NUM>, and laterally narrower at an intermediate distance from the base region <NUM>. Thus, the track portion <NUM> may be regarded as having an 'hourglass' shape, and/or an outwardly tapering terminal part <NUM> distal from the base region <NUM>.

Each of the first and second track regions <NUM>, <NUM> has a terminal surface <NUM>, <NUM>, respectively. The terminal surfaces <NUM>, <NUM> correspond to the parts of the first and second track regions <NUM>, <NUM> which are distal from the base region <NUM>.

The terminal surfaces <NUM>, <NUM> of the track portion <NUM> together provide the bearing surface which is, in use, engaged by the friction surface <NUM>. It will be appreciated that the terminal surfaces <NUM>, <NUM>, are substantially planar in form, and that the bearing surface, may also be regarded as being generally planar in form.

The guide track arrangement <NUM> illustrated in <FIG> is disclosed in greater detail in the present applicant's earlier <CIT>, the entire disclosure of which is hereby incorporated herein by reference.

The bottom cavity <NUM> is shaped to be complementary to the shape of the track, or guide rail, portion <NUM> as described above. That is, the bottom cavity <NUM> provides a narrower lower region <NUM> (which is slightly wider than the narrowest region of the track portion <NUM> to allow the draw bar to slide, but narrower than the terminal part of the track portion <NUM>), and a wider upper region <NUM> (which is slightly wider than the terminal part of the track portion <NUM>).

The lower narrower lower region <NUM> of the bottom cavity <NUM> may be regarded as being defined by first and second lower side portions <NUM>, <NUM> of the base region <NUM> which are spaced apart such that they define a width of the narrower lower region <NUM> of the bottom cavity <NUM> which is slightly wider than the narrowest region of the track portion <NUM>, but narrower than the terminal part <NUM> of the track portion <NUM>. In this embodiment, the bottom cavity <NUM> is substantially at the lateral centre of the draw bar <NUM>, and of the brake assembly <NUM>. First- and second-side bottom surfaces <NUM>, <NUM> of the draw bar <NUM> engage respective upwardly facing surfaces <NUM>, <NUM> of the elongate track element <NUM>, to at least partially support the draw bar on the elongate track element <NUM>. It is to be understood that the draw bar <NUM> would also, in use, be supported at its other end (for example, its top) by a similar engagement arrangement (or, if desired, by any other desired and suitable engagement arrangement).

<FIG> illustrate use and/or operation of the brake assembly <NUM> in conjunction with elongate track element <NUM>. The draw bar main body <NUM>, and the flexible material forming the screen <NUM>, are omitted from these drawings for clarity.

<FIG> is a view, from the rear, of the brake assembly <NUM> engaged on and with the elongate track element <NUM>, which is shown in transverse cross section.

The outwardly tapering terminal part <NUM> of the track portion <NUM> may be regarded as being retained within the bottom cavity <NUM> of the brake assembly <NUM>. Alternatively, the first and second lower side portions <NUM>, <NUM> of the base region <NUM> (which define the width of the narrower lower region <NUM> of the bottom cavity <NUM>) may be regarded as being trapped under, and retained by, the tapering terminal part <NUM> of the track portion <NUM>. As shown in <FIG>, the brake pad <NUM> is in contact with the bearing surface provided by terminal surface <NUM>, <NUM>, of the track portion <NUM>.

The withdrawal member <NUM> is connected to the brake member <NUM> by engagement of a connecting portion <NUM> of the withdrawal member <NUM> with or through the connection formation (aperture <NUM>) of the stem <NUM>. In the configuration shown in <FIG>, no substantial force is applied to the brake member <NUM> by the withdrawal member <NUM>, and the friction surface <NUM> of the brake pad <NUM> is maintained in contact with the bearing surface (terminal surfaces <NUM>, <NUM>) by the bias force applied by the spring <NUM> (not shown in <FIG>).

Because the guide channel provided by the elongate guide cavity <NUM> is provided substantially at the lateral centre of the guide rail (provided by the track portion <NUM>), the connection of the screen material to the draw bar <NUM> may easily be configured so it is spaced equidistant to each side of the guide rail, and equidistant to each side of the draw bar <NUM>.

Thus the retaining channel <NUM> in the draw bar <NUM> is in use aligned with the retaining channel portion <NUM> (visible in <FIG>), which is provided substantially laterally centrally in relation to the bottom cavity <NUM> of the brake assembly <NUM>, and in relation to the brake assembly as a whole. Having the retaining channel <NUM>, and retaining channel portion <NUM>, substantially aligned with the opening of the guide cavity <NUM>, which retains the bottom edge of the screen material, allows the extension of the screen material from the draw bar <NUM> into the guide cavity <NUM> to be aligned with the lateral centre of the draw bar. Such an arrangement is aesthetically pleasing in its symmetry and can avoid substantial torque on the draw bar and its engagement with the guide rail being imparted by a retraction force applied to the draw bar by the screen, or by a short period of higher than normal friction between the screen edge and the interior of the guide channel,. This can assist smooth running of the draw bar on the guide rail as it slides therealong, for example, between an open position towards the roller onto which the screen material can be wound and unwound and a closed position further away from the roller.

<FIG> is front perspective view of the brake assembly <NUM> corresponding to <FIG>.

As shown in <FIG>, the guide track arrangement <NUM> is provided with an end piece <NUM>, which provides a catch portion <NUM> for interaction with the latch member <NUM>. The end piece <NUM> comprises an end panel <NUM> adapted to abut an axial end of the guide track arrangement <NUM>, a first-side member <NUM> adapted to align with a first lateral side of the guide track arrangement <NUM> and a second-side member <NUM> adapted to align with a second lateral side of the guide track arrangement <NUM>.

The end cap <NUM> further comprises a cavity projection <NUM> which projects perpendicular to the end panel <NUM> and which is adapted to project a short distance into an end region of the guide cavity <NUM> that has been left without any of the track runner <NUM> provided therein. The cavity projection <NUM> is sized and shaped to fit closely to the interior walls of the guide cavity <NUM>.

A catch portion <NUM> projects from the cavity projection <NUM> and, in use, projects outwardly to provide a catch formation for engagement by, and retention of, the latch member <NUM>. This can assist in retaining the draw bar in a position corresponding to the fully extended (closed) position of the screen. The catch portion <NUM> provides a ramp portion <NUM> on a side which in use faces towards the roller of the screen, to enable the latch member <NUM> to ride over the catch portion <NUM> merely by movement of the draw bar <NUM>, and an abutment portion <NUM> on a side which in use faces away from the roller of the screen, to provide capture of the latch member <NUM>, unless it is deliberately released. This can allow the latch member <NUM> to be engaged automatically upon full extension of the screen, but to require deliberate and/or manual release in order to allow movement of the draw bar from that position in the retraction direction of the screen, as will be described further in due course. Further detail of the end piece <NUM> is provided in in the present applicant's earlier <CIT>, incorporated herein by reference.

<FIG> is cross sectional view on XV-XV in <FIG>, also corresponding to the configuration, or state, of the brake assembly <NUM>, as shown in <FIG>. The configuration, or state, of the brake assembly <NUM>, as shown in <FIG> may be regarded as the state when the draw bar <NUM> is stationary and the brake apparatus <NUM> is resisting movement of the draw bar <NUM> in the retraction direction of the screen (referred to herein as the rear or rearwards direction in relation to the draw bar).

As illustrated, the friction surface <NUM> of the brake pad <NUM> is maintained in contact with the bearing surface (terminal surfaces <NUM>, <NUM>) by the bias force applied by the spring <NUM>.

The same broken-line double headed arrow, designated 'A', has been added in <FIG> as is shown in <FIG>, and is to the same scale to the brake arrangement. The arrow a illustrates the arcuate path of the axis of the stub axles <NUM>, <NUM>, as defined by the link members <NUM>, 90A (even though the stub axles <NUM>, <NUM> are not visible in the laterally central cross sectional view of <FIG>).

It should appreciated that, as illustrated in <FIG>, the engagement of the bearing surface by the friction surface <NUM> prevents the brake member <NUM> from reaching the position (referred to as the 'fully extended position') illustrated in <FIG>, but causes the brake member <NUM> to be held in a position just offset from this fully extended position.

<FIG> includes an enlargement of the region where the friction surface <NUM> engages the bearing surface, and to illustrate the difference in position between the 'working' (<FIG>) position of the brake member and the fully extended (<FIG>) position of the brake member <NUM> circles illustrating the positions of the stub axles have been added to the enlargement. The circle designated 'W' illustrates the position of the stub axles <NUM>, <NUM> in the 'working' (<FIG>) position, and the circle designated 'E' illustrates the position of the stub axles <NUM>, <NUM> in the 'fully extended' (<FIG>) position.

Frictional forces between the friction surface <NUM> and the bearing surface which result from movement or forcing of the draw bar <NUM> in the retraction direction of the screen (i.e. to the left in <FIG>), will force the brake member <NUM> to the right as illustrated in <FIG>, relative to the housing <NUM>. However, the path of the brake member <NUM> is constrained by the link members <NUM>, 90A so that it cannot move linearly in the front-rear direction of the brake assembly. That is, the brake member <NUM> cannot move directly to the right, relative to the housing <NUM>. Rather, forcing the brake member to the right relative to the housing causes movement (or forcing) of the brake member in a direction which has a direction component towards the bearing surface thus forcing the friction surface <NUM> against the bearing surface and increasing braking force. More specifically, with reference to <FIG>, forcing the brake member <NUM> to the right, relative to the housing <NUM>, forces the brake member <NUM> towards the fully extended position.

Thus it will be appreciated that the described embodiment, as illustrated in <FIG>, in addition to the braking force provided by the engagement of the friction surface with the bearing surface which results from the bias force applied by the spring <NUM>, provides a force-increasing arrangement for increasing the force with which the friction surface engages the bearing surface. Further, the force-increasing arrangement converts at least some of a frictional force applied between the friction surface and the bearing surface into additional contact pressure force applied to the brake member to increase contact pressure between the friction surface and the bearing surface.

The additional force applied to the brake member may easily be released, either by moving the draw bar in the extension direction (to the right as illustrated in <FIG>) or by operating a brake release mechanism (such as a handle) to compress the spring <NUM> and withdraw the brake member <NUM>, as illustrated, for example, in <FIG> and <FIG>.

Further, it will be appreciated that a frictional force between the friction surface <NUM> and the bearing surface which results from forcing or movement of the draw bar in the extension direction of the screen will not result in additional contact pressure force applied to the brake member <NUM>, nor increase contact pressure between the friction surface and the bearing surface. Thus the described embodiment allows a strong braking force to be applied to counteract inadvertent or undesired retraction of the screen due to the bias force applied by the roller, but provides substantially less braking force when the screen is being closed. This can allow the screen to be manually closed, by movement of the draw bar in the screen extending direction, with ease, and if desired without operation of a brake release mechanism (handle).

<FIG> illustrate operation of the latch member <NUM>.

<FIG> is a cross section view of the apparatus of <FIG>, on the same plane as the <FIG> cross sectional view, illustrating the latch member <NUM> of the brake assembly <NUM> riding up the ramp portion <NUM> of the catch portion <NUM>, as the draw bar <NUM> is moved to a fully closed position of the screen. Engagement of the terminal region <NUM> of the catch engaging part <NUM> of the latch member <NUM> with the ramp portion <NUM> causes the latch member to move substantially in the axial direction of the brake assembly <NUM>, guided by the passage <NUM>, provided between the internal wall portion <NUM> and the front portion <NUM> of the base portion <NUM>. This causes a corresponding movement of the moveable seat <NUM>, compressing the spring <NUM>, but does not necessarily disengage the friction surface <NUM> from the bearing surface <NUM>, <NUM>. It will be appreciated that apart from moving the draw bar into the full closed position of the screen, no specific action (such as operation of a handle) is required by a user in order to engage the latch mechanism.

<FIG> illustrates the brake assembly <NUM> when the draw bar has moved slightly further to fully closed position of the screen than in <FIG>. The latch member <NUM> has moved past the ramp portion <NUM> and has been forced substantially back to its normal position, first-side surface <NUM> of the actuating part <NUM> of the latch member is biased against the engagement parts <NUM>, <NUM> (not shown in <FIG>) of the brake member <NUM> by the spring <NUM>. The catch engaging part <NUM> of the latch member <NUM> is constrained by the catch portion <NUM>, preventing movement of the draw bar <NUM> in the retraction direction of the screen until the latch mechanism is released.

<FIG> illustrates release of the latch member <NUM> from the catch portion <NUM>. This can be effected by operation of a brake release mechanism (handle), that is, by the same action that is used to withdraw the friction surface <NUM> from the bearing surface. When the brake member <NUM> is withdrawn, the engagement parts <NUM>, <NUM> force the latch member in the second axial (withdrawal) direction of the brake assembly, thus allowing disengagement of the catch engaging part <NUM> from the catch portion <NUM>. Thus when the latch member <NUM> is operated to release the latch mechanism and allow movement of the draw bar <NUM> in the retraction direction of the screen, the friction surface is also withdrawn from the bearing surface, as required to facilitate movement of the draw bar <NUM> in the retraction direction.

<FIG> is a cross section view of the apparatus of <FIG>, on the same plane as the <FIG> cross sectional view, illustrating movement of the brake assembly, in the retraction direction of the screen, away from the catch, with the friction surface <NUM> withdrawn from the bearing surface, by operation of the handle by a user. The draw bar may be moved, to in the retraction direction of the screen, to any desired position, for example, to the fully open position of the screen, or to any desired partially open position of the screen, by a user moving the draw bar using the handle (or while the handle is operated to maintain a withdrawn position of the brake member. If the handle is released, the bias force applied by the spring <NUM> will force the brake member in substantially the first axial direction of the brake assembly, so that the friction surface engages the bearing surface, putting the brake assembly substantially into the condition shown in <FIG>. Thus after release of the handle further, undesired, movement of the draw bar in the retraction direction of the screen will be prevented by the brake assembly <NUM>.

A particular embodiment has been illustrated and described by way of example.

Any desired and suitable materials could be used for the parts described and illustrated. In a particular embodiment, the housing <NUM>, brake member <NUM>, link members <NUM>, 90A, latch member <NUM> and moveable seat <NUM> are made from suitable plastics. These parts may be manufactured, for example, solely or primarily by injection moulding. The spring <NUM> and connecting pin <NUM> may be made from metal such as a suitable types of steel.

In a particular embodiment, the brake pad <NUM> is made from, or comprises, a SEBS (Styrene Ethylene Butylene Styrene) polymer material, and may be co-moulded (injection moulded) onto the brake shoe <NUM> (or more generally the rest of the brake member <NUM>). SEBS is considered suitable due to its appropriate frictional and abrasion-resistant characteristics and its suitability for co-moulding onto the brake shoe <NUM> (or more generally the rest of the brake member <NUM>), which may be made from polypropylene. Although not visible in the drawings, the brake shoe may include fins, ribs or other projections extending from the inner surfaces of one or more of the wall portions 53A, <NUM>, <NUM>, to increase contact surface area with the brake pad and enhance adhesive and/or mechanical bonding with the brake pad material.

In relation to the brake pad, it will be appreciated that alternative materials and attachment methods may be used: for example, the brake pad <NUM> may be made from any suitable material (including particularly, but not necessarily exclusively, polymer, elastomer, thermoplastic and/or rubber) and attached to the brake shoe <NUM> (or more generally the rest of the brake member <NUM>) by any suitable arrangement.

It will be appreciated that at least the illustrated embodiment of a brake arrangement can assist significantly in securing a draw bar against inadvertent movement in the retraction direction by the force applied by the biased roller.

The illustrated embodiment can assist in overcoming a lack of braking force which can afflict prior art brake arrangements which rely substantially solely on a bias force provided by a spring to force a brake against a guide track of a blind.

The illustrated embodiment can provide sufficient braking force without requiring an unduly strong biasing spring that would be stiff to release. This can provide a number of advantages, including: ease and pleasantness of use, due to only a relatively light force needing to be manually applied to the handle to release the brake; reduced strain on release cable/handle components, especially during release, thereby increasing component life and reliability and/or allowing use of lighter and/or more economical components; and reduced resistance by the latch member to riding over the catch.

Compared to use of a brake arrangement similar in structure to the illustrated embodiment but without the force-increasing mechanism, the illustrated embodiment can provide increased braking force against movement in the retraction direction of the screen, which can assist in overcoming or mitigating reduced friction between the brake pad and the track that may occur during use, for example due to contamination wear or aging of the brake surface, moisture on the guide track, or other circumstances.

Further, the illustrated embodiment provides a mechanism in which the same releasing action is required of a user, irrespective of whether latch is engaged on the catch, or not.

As braking force needs to only resist movement of the draw bar in the opening (retraction) direction, it is an elegant solution to provide a brake arrangement which provides a greater breaking force in this direction than in the closing direction.

Of course, the above features or functionalities described in relation to the disclosed embodiments are provided by way of example only, and should not be taken as a necessary or provided by all embodiments of the invention.

Claim 1:
A draw bar (<NUM>) for a retractable screen arrangement (<NUM>) in which a screen material (<NUM>) is extensible across an opening (<NUM>) by movement of the draw bar (<NUM>) in an extension direction in order to screen or partially screen the opening (<NUM>), and in which the screen material (<NUM>) is retractable by movement of the draw bar (<NUM>) in a retraction direction, to reduce occlusion of the opening (<NUM>) by the screen material (<NUM>) and in which the screen arrangement (<NUM>) applies a retraction force, in the retraction direction, to the screen material (<NUM>), to assist retraction of the screen material; wherein
the draw bar (<NUM>) comprises:
a brake arrangement (<NUM>) for providing a braking force between the draw bar (<NUM>) and a bearing surface of a track (<NUM>) which in use guides the draw bar (<NUM>) to resist relative movement of the brake arrangement (<NUM>) and the bearing surface in at least one direction, the brake arrangement (<NUM>) comprising:
a brake member (<NUM>) which provides a friction surface (<NUM>) for contacting the bearing surface;
a brake member support (<NUM>) for supporting the brake member (<NUM>); and
a forcing arrangement for forcing the friction surface (<NUM>) against the bearing surface;
wherein the forcing arrangement comprises:
a biasing arrangement (<NUM>) for biasing the friction surface (<NUM>) towards the bearing surface, and
a force increasing arrangement for increasing the force with which the friction surface (<NUM>) engages the bearing surface,
characterized in that the force increasing arrangement is configured to increase the force with which the friction surface (<NUM>) engages the bearing surface by converting at least some of a frictional force applied between the friction surface (<NUM>) and the bearing surface into additional contact pressure force applied to the brake member (<NUM>) to increase contact pressure between the friction surface (<NUM>) and the bearing surface,
and in that the force increasing arrangement comprises a forcing part (<NUM>) having a first region (<NUM>) connected to the brake member support (<NUM>), a second region (<NUM>) connected to the brake member (<NUM>) , and an intermediate region for transmitting force between the first region (<NUM>) and the second region (<NUM>).