GB2509310A

GB2509310A - Variable visibility panel unit

Info

Publication number: GB2509310A
Application number: GB201223255A
Authority: GB
Inventors: Stephen Hutsby; Daren Arthur Sharpe
Original assignee: INTERIORS Manufacturing Ltd; TRACE MACHINING Ltd
Current assignee: INTERIORS Manufacturing Ltd; TRACE MACHINING Ltd
Priority date: 2012-12-21
Filing date: 2012-12-21
Publication date: 2014-07-02
Also published as: GB201223255D0; GB2509310A8

Abstract

A panel unit comprises a static panel having a transparent region and an opaque region, and a moveable panel positioned substantially parallel to the static panel and having a transparent region alignable with the transparent region of the static panel, and an opaque region alignable with the transparent region of the static panel. The panel unit also has a cam and follower arrangement connected to the moveable panel. The cam and follower arrangement comprises two followers and a cam. One of the followers is configured to interact with the cam so as to linearly move the moveable panel relative to the static panel in one direction, and the other follower is configured to interact with the cam so as to linearly move the moveable panel relative to the static panel in an opposite direction. Also disclosed is a panel unit comprising two cams, each mounted for actuating separate panels.

Description

A Panel Unit

FIELD OF THE INVENTION

The present invention relates to a panel unit and/or a door or window comprising a panel unit.

BACKGROUND OF THE INVENTION

Panel units may be provided in windows or in doors so as to permit sdectively vanable visibility through the window or door. For example, in a hospital room, for patient privacy, the panel unit may be adjusted so as to be fully opaque. However, at other times the panel unit may be adjusted to have increased transparency, so, for example nurses can look in a patient's room without disturbing the patient. Panel units may also be used in many other situations, for example, pharmacies, banks, offices, or homes.

GB 1296594 describes a conventional arrangement of a pane' unit. In a conventional arrangement. a slidaNe panel is arranged between two static panels. A cam abuts an edge of the slidable panel, and rotation of the cam causes the slidable panel to slide relative to the static panels. One of the static panels and the slidable panel are covered with opaque and transparent strips. Generally, the opaque strips cover approximately 65% of the panels and the transparent strips cover approximately 35% of the panels.

The opaque and transparent strips are arranged such that the slidable pand can be moved between a position where visibility through the panel unit is fully obscured and a position where visibility through the panel unit is only obscured by approximately 65%.

The conventional panel unit is designed for vertical movement of the slidable panel, i.e. the cam moves the panel in an upward direction and gravity permits the panel to move in a downwards direction. However, there is now a desire in the market for panel units having verically rather than horizontally positioned strips, which means that the slideable panel needs to be slidable horizontally rather than vertically. This is not possible with the conventional panel unit, as no return mechanism is provided.

I

Further, the use of gravity to lower the slidable panel to a lower position, means that a user has little control over the downward movement of the panel. Attempts have been made to address this problem. An example of this is shown in 0B2489271 which uses dampers within the panel unit to damp the downward movement of the slidable panel.

However, this adds to the complexity of the unit.

Yet further, there is a desire on the market for panel units that extend to cover a large extent of a door and have variable visibibty across the full extent of the pand unit.

The conventional design of panel unit is not suitable for such an application because of the weight of such a large panel requires a user to apply a large force to rotate the cain to slide the sliable window upwards. The additional weight of the panel would also worsen the problem of lack of control of movement of the slidable panel when the sfidable panel is thwered. In the standard design, it is a'so necessary to locate the handle at the bottom of the panel unit. This means that if the panel unit were modified to cover a large extent of the door, the handle would inconveniently be located towards the bottom of the door.

SUMMARY OF THE INVENTION

The present invention aims to alleviate one or more of the problems associated with

panel units of the prior art.

A first aspect of the invention provides a panel unit having selectively variaNe visibility therethrough, the panel unit comprising: a static panel having a transparent region and an opaque region; a moveable panel positioned substantially parallel to the static panel and having a transparent region alignable with the transparent region of the static panel for maximum visibility through the panel unit, and an opaque region alignable with the transparent region of the static panel for minimum visibility through the panel unit; a cam and follower arrangement connected to the moveable panel.

wherein the cam and follower arrangement comprises two followers and a cam, one of the followers being configured to interact with the cam so as to linearly move the moveable panel relative to the static panel in one direction, and the other follower being configured to interact with the cam so as to linearly move the moveable panel relative to the static panel in an opposite direction, so as to vary the visibility through the panel unit.

The provision of two followers means that the moveable panel can be moved as a result of the cam interacting with the one or other of the followersrather than relying on gravity to move the moveable pand in one direction, as with the pand units of the prior art. This is advantageous because it permits the moveable panel to be linearly moved in both directions either horizontally or vertically, so permits an increased variation of installations.

The two followers also alleviate a problem of jamming of a moveable panel, which can sometimes be seen with panel units of the prior art.

The transparent region may comprise a plurality of transparent sub-regions, and the opaque region may comprise a plurality of opaque sub-regions. One transparent sub-region of the moveable pand may be substantially alignable with one of the transparent sub regions of the static panel or with one of the opaque sub-regions of the static panel.

The cam and follower arrangement may comprise an aperture. One of the followers may be defined by one surface of the aperture, and the other follower may be defined by another surface of the aperture.

The cam may be captive within the aperture. An aperture that captures the cam helps to reduce any potential risk of the moveable panel breaking, e.g. if the moveable panel is non-reinforced glass.

The aperture may be formed in the moveable panel, and the cam may be positioned within the aperture.

The cam may be a rotary cam. Rotation of the cam may cause the cam to contact an edge of the aperture to move the moveable panel, e.g. the cam may push against an edge of the aperture. Alternatively, the cam may be a linear cam.

When the cam is a rotary cam, movement of the cam through 900 may move the opaque region of the moveable glass from alignment with the transparent region of the static pand to alignment with the opaque region of the static panel.

The cam may have two positions of stability, e.g. corresponding to a position where the panel unit has minimal visibility therethrough and a position where the panel unit has maximum visibility therethrough. The cam may have more than two positions of stability, e.g. corresponding to a position of the panel unit having minimal visibility therethrough, a position of the panel unit having maximum visibility therethrough. and one or more positions therebetween.

The aperture may be substantially rectangular shaped with a stepped corner. One edge of the aperture may define one of the followers and the step of the stepped corner may define the other of the followers. The shape of the aperture also provides a stop to prevent over rotation of a rotary cam.

The panel unit may comprise a further moveable panel (e.g. the panel unit may comprise a first moveable panel and a second moveable panel). The further moveable panel may have a transparent region alignable with the transparent region of the static panel, and an opaque region alignable with the transparent region of the static panel.

For minimum visibility through the panel unit, the opaque region of both the moveable panel and the further moveable panel may be aligned with a portion of the transparent region of the static panel. Having two moveable panels means that the area of coverage of the transparent region on the static, movable and further moveaNe panels can be increased. An increased transparent region means that in a position of maximum visibility the visibility through the panel unit is increased compared to panel units of the prior art. The transparent region of each of the static, moveable and further moveable panels may cover a region having a height or width of up to 150, 160, 170, 180, 190 or 200%, or any percentage therebetween, of that of the opaque region.

A further cam and follower arrangement may be connected to the further moveable panel. The further cam and follower arrangement may be configured to interact so as to linearly move the further moveable panel relative to the static panel. The further cain and follower arrangement may comprise two followers. The two followers may be defined by an aperture. The further cam may be connected to and fixed relative to the cam. The provision of a second cam and moveable panel can aid in alleviating problems of lack of control of movement in one direction of movement of the moveable panel, associated with the single panelled panel units of the prior art. The cam and further cam may be rotary cams. Rotary cams further improve the control provided to a user. That is, when the cam and further cam are rotated to move the movable and further moveable panel, the counterbalance provided by the moveable and the further moveable panel yet further alleviates the problem of lack of control associated with pnor art panel units, and also mitigates the need for additional dampers in the panel unit. The counterbalance also enables larger moveable panels to be used, because the counterbalance enables a larger load to be lifted by the cain for the same torque input.

An aperture may be formed in the further moveable panel within which the further cam may be positioned. The further cam may be captive within the aperture of the further moveable panel.

The panel unit may compnse an actuator for causing interaction of the cain and follower alTangement. The actuator may also cause interaction of the further cam and follower arrangement. The actuator may move the cam or move one or more of the followers. The actuator may be shaft. The shaft may be rotataHe, such that when the cam is a rotary cam, rotation of the shaft rotates the cam.

The pand unit may comprise a handle connected to the actuator for a user to actuate the actuator. For example, in an embodiment where the cam is a rotary cam, turning the handle through 90° may turn the cam through 90°. In an alternative embodiment, a tool interface may be provided, for example a square or hex drive. Further alternatively, the actuator may be capable of being moved directly by a user. for example, the actuator may be a portion formed on or connected to the cain and follower arrangement.

The cam may be positioned in a central region of the panel unit. In such embodiments, the aperture may be positioned in a central region of the moveable panel. Alternatively, the cam may be positioned in a lower region of the panel unit.

In such embodiments, the aperture may be positioned in a lower region of the moveable panel. Further alternatively, the cam may be positioned to one side of the panel unit. In such embodiments, the aperture may be positioned to one side of the moveable panel. Yet further alternatively, the cam may be positioned in an upper region of the panel unit. In such embodiments, the aperture may be positioned in an upper region of the moveable panel.

The opaque and transparent regions of the panels may comprise a plurality of linear strips extending across each of said panels. The moveable panel may be linearly moveable in a direction perpendicular to the direction of the strips. For example, the strips may extend in a horizonta' direction and the movable panel may move in a vertical direction. Alternatively, the strips may extend in a vertica' direction and the moveable panel may move in a horizontal direction. The opaque regions may be formed, for example, using frosted gbss, paint or opaque material adhered to the panel, or any other suitable means.

The panel unit may comprise a further static panel. The static and further static panel may be positioned on othermost sides of the panel unit, such that the moveable panel is positioned therebetween. In embodiments comprising the further moveable panel, the further moveable panel may also be positioned between the static panel and further static panel. Positioning the moveable panel, and optiona'ly the further moveable panel, between two static panels protects the moving parts (i.e. the movable panel and further movable panel), which can prolong the life of the panel unit.

The further static panel may comprise opaque and transparent regions. The opaque and transparent regions of the further static panel may be substantially coincident with the opaque and transparent regions of the static panel. Providing two static panels with substantially coincident (e.g. substantially aligned) opaque and transparent regions, and the moveable panel(s) arranged therebetween, further reduces visibility through the panel unit when viewed at an angle (i.e. there is a reduced range of angles of fine of sight through the panel unit).

The panel unit may comprise one or more stnps positioned on one or more of the panels to ease sliding of adjacent panels. For example, low friction tape may be positioned on a perimeter of the moveable panel and/or static panel. The low friction tape may be PTFE tape. Alternatively, or additionally, the panel unit may comprise one or more spacers to support the panels and maintain the spacing therebetween.

A second aspect of the invention provides a panel unit having selectively variable visibility therethrough, the panel unit comprising: a static pand having a transparent region and an opaque region; a first moveable panel positioned substantially parallel to the static panel and having a transparent region alignable with the tnmsparent region of the static panel, and an opaque region alignable with the transparent region of the static panels; a second moveable panel positioned substantially parallel to the static panel and the first moveaNe panel and having a transparent region alignable with the transparent region of the static panel, and an opaque region alignable with the transparent region of the static panel; and two cams, one cam being positioned for actuating the first moveable panel, and the other cam being positioned for actuating the second moveable panel; wherein the two cams are connected to each other, and fixed relative to each other, such that movement of the two cams causes the first and second moveable panels to move linearly in opposite directions.

When the panel unit is used in a vertical orientation, and the first moveable panel is moved in a downwards direction, at the same time the second moveable panel is moved in an upwards direction. The counterbalance provided by the concurrent movement of the first and second moveable panels provides a user with more control over the movement of the panels, than panel units of the prior art, without the need for additional dampers to be provided within the panel unit.

Further, if desired, larger moveable panels can be used than panel units of the prior art because the counterbalance enables the cams to lift a larger load for the same force or torque input.

The static panel may be a single panel or it may be made by adjoining two sub-panels.

The two cams may be rotary cams. The two cams may be arranged substantially perpendicular to each other. Rotary cams further improve the mechanical advantage provided by the counterba'ance. Alternativdy, the cams may be linear cams.

The first and second moveable panels may be positioned such that the transparent regions of the first moveaNe panel and the second moveable panel are each alignable with the transparent region of the static panel. The opaque region of the first moveable panel may be each configured to partially cover the transparent region of the static panel, and the opaque region of the second moveable panel may be configured to partially cover the same transparent region of the static panel. The opaque region of the first moveable panel may be offset in a plane of the panel unit from the opaque region of the second moveable panel. The opaque region of the first moveable pand and the opaque region of the second moveable panel my be arranged to be alignable to each partially cover the transparent region of the static panel, so as to restnct visibility therethrough. Having such an alTangement of two moveable panels means that the area of coverage of the transparent region on the static, and first and second movable panels can be increased. An increased transparent region means that in a position of maximum visibility the visibility through the panel unit is increased compared to panel units of the prior art. The transparent region of each of the static. moveable and further moveable panels may cover a region having a height or width of up to 150. 160. 170, 180, 190. 200%, or any percentage therebetween, of that of the opaque region.

Alternatively, the first moveable panel may be moveable in a lower region of the panel unit and the second moveable panel may be moveable in an upper region of the panel unit.

The panel unit may comprise an aperture formed in the first moveable panel and second moveable panel. One of the two cams may be positioned within each aperture and configured to contact an edge of the respective aperture to move the first and second moveable panels.

The aperture may be substantially rectangular shaped with a stepped corner.

The panel unit of the second aspect may have any one, or any combination of, optional features of the first aspect.

A third aspect of the invention provides a door comprising a window formed using the panel unit according to the first or second aspect.

The length of the window may extend at least 50% of the height of the door.

Alternatively, the length of the window may extend less than 50% of the height of the door. The movable panel may be linearly moveable in either a vertical direction or a horizontal direction.

A fourth aspect of the invention provides a window formed using the panel unit according to the first or second aspect. The movable panel may be linearly moveaNe in either a vertical direction or a horizontal direction.

BRIEF DESCRIPTION OF THE DRAWINGS

Embodiments of the invention will now be descnbed with reference to the accompanying drawings, in which: Figure 1 shows a front view of a panel unit according to an embodiment of the invention; Figure 2 shows a sectioned view through a vertical cross section of the panel unit shown in Figure 1; Figure 3 shows a front view of a moveaNe panel of the panel unit of Figure 1; Figure 4 shows a perspective view from the front of two cams used in the panel unit of Figure 1; Figure 5 shows schematically movement of two moveable panels of the panel unit of Figure 1 during operation; Figure 6 shows one of the canis of Figure 4 in an aperture of a moveable panel of the panel unit shown in Figure 1; Figure 7 shows a front view of a door having the panel unit of Figure 1; Figure 8 shows a front view of a wall having a window including the panel unit of Figure 1; Figures 9A and 9B show a front view of doors having an alternative panel unit; Figure 10 shows a sectioned view through a vertical cross section of a further alternative panel unit; Figure 11 shows a sectioned view through a cross section of yet a further alternative panel unit; and Figure 12 shows schematically a cross section side view of a panel unit in a position of minimal visibility.

DETAILED DESCRIPTION OF EMBODIMENT(S)

Referring to Figures 1 and 2, a panel unit is indicated generally at 10. The panel unit includes two static panels 12, 14. In this embodiment, two moveable panels 16, 18 are positioned in a region between the two static panels 12, 14. In this embodiment the static and moveable panels are made from glass. However, in alternative embodiments, the static and moveable panels may be made from any other suitable transparent material, for example poly(methyl methaciylate) (PMMA), e.g. perspex.

One of the moveable panels 16 is shown in Figure 3. The moveable panel 16 is similar to the moveable panel 18. The moveable pands 16, 18 each comprise an aperture 20, 22 formed therein. In this embodiment, the aperture 20, 22 is positioned substantailly centrally in a lower half of the moveable panels 16, 18. However, in alternative embodiments the aperture 20, 22 could be positioned in any desired location, for example in a lower region, in an upper region, and/or to one side of the moveable panels 16, 18. The aperture 20, 22 is substantially rectangular with a stepped corner 24 (stepped corner only illustrated in Figures for aperture 20).

Two cams 26, 28 are provided in the panel unit 10 for moving the movable panels 16, 18. One of the cams 26 is associated with one of the moveable panels 16 and positioned within the aperture 20 thereof. The other of the cams 28 is associated with the other moevable panel 18 and positioned within the aperture 22 thereof. In this embodiment, the cams 26, 28 are captive in the respective apertures 20, 22. The apertures 20, 22 and cams 26, 28 are dimensioned such that rotation of the cams 26, 28 causes contact of the respective cam with the respective aperture.

A shaft 30 extends through the width of the panel unit 10. In this embodiment the shaft terminates in two handles 32, 34, each positioned on an outerside of the pand unit 10. Iii alternative embodiments, only one handle may be provided on only one of the outersides of the panel unit. Further alternatively, a key, knob, lever or tool inteiface (e.g. square or hex drive) may be provided instead of a handle. The cams 26.

28 are fixed relative to the shaft 30, and as such are connected together via the shaft and also fixed relative to each other via the connection to the shaft. The cams 26, 28 may be fixed to the shaft in any conventional manner.

Referring to Figure 4, the cams 26, 28 are shown in isolation. The hole through which the shaft 30 extends through is indicated at 36. The cams 26. 28 are arranged perpendicularly to each other. Referring now also to Figure 5. it can be seen that the perpendicular arrangement of the cams 26, 28, means that when the cams 26, 28 are rotated in one direction A (labeled A in Figure 5). moveaNe panel 16 is raised (indicated by arrow a) and moveable panel 18 is lowered (indicated by arrow b).

Conversely, when the cams 26, 28 are rotated in the opposite direction B (labeled B in Figure 5), moveable panel 16 is lowered (indicated by arrow c), and moveable panel 18 is raised (indicated by arrow d).

Referring to Figure 6. one of the cams 26 is shown in the respective aperture 20. In the position and orientation shown in Figure 6. the moveable panel 16 is in a lowered position. To move to a raised position, the cam 26 is rotated in an anti-clockwise direction indicated by arrow 1. This causes the moveable panel 16 to move in an upward direction (indicated by arrow 2). To move the moveable panel to a lowered position the cam is rotated in a clockwise direction. Rotation in a clockwise direction pushes against a corner of a step formed in the aperture 20, which permits the cam to move back to the position shown in Figure 6. The other cam 28 and aperture 22 of the other moveable panel are arranged in a similar manner, but the aperture 22 is a mirror image of the aperture 20. Advantageously, the shape of the aperture 20, 22 provides (in addition to follower surfaces) a stop to prevent over rotation of the respective cam 26, 28.

Referring again to Figure 2, low friction tape, in this embodiment PTFE tape 46, 48, is positioned to be between the moveable and static panels. In this embodiment.

S the PTEE tape is positioned along the longitudina' edges of the moveaNe panels 16.

18. In this embodiment, the PTFE tape is approximately 0.5 mm thick. PTFE tape is provided on two faces of moveable panel 16, i.e. to be between moveable panel 16 and static panel 12, and between moveable panel 16 and moveable panel 18. PTFE tape is provided on one face of the moveable panel 18 to be positioned between moveable panel 18 and static panel 14. In alternative embodiments, an alternative low friction tape may be used instead of PTFE tape. In further alternative embodiments.

the low friction tape may be positioned on the static panel instead of on the moveable panel, in such embodiments, low friction tape may also be provided on one of the moveable panels so as to be positioned between the two moveable panels.

In yet a further embodiment, no low friction tape may be used, and instead spacers may be positioned between the static and moveable panels. The spacers may be positioned so as to substantially maintain the spacing between the static and moveable panels. The spacers may be of a kind known in the art. In another embodiment, a combination of low friction tape and spacers may be used.

Referring now to Figures I to 3 and 12, the static panels 12, 14, and the moveable panels 16. 18 indude transparent and opaque regions. The transparent regions of the two static pands are substantially aligned and the opaque regions of the static pands are substantially aligned. In alternative embodiments only one of the static panels may include transparent and opaque regions, and in such cases the other static panel may be fully transparent. In this embodiment, the transparent region of the static panels 12, 14 includes a plurality of parallel transparent strips. 38a, 38b, and the opaque region includes a plurality of parallel opaque strips 40a, 40b (only one of the transparent and opaque strips are labeled for clarity) interspaced between the transparent strips. 38a. 38b. Similarly, the transparent region of the moveable panel includes a plurality of transparent strips 42a, 42b. and the opaque region includes a plurality of opaque strips 44a, 44b interspaced between the transparent stnps 42a, 42b.

In this embodiment, the transparent strips 38a, 38b, 42a, 42b of the static panels 12, 14 and moveable panels 16, 18 are approximately twice the thickness of the opaque strips 40a, 40b, 44a, 44b.

In the present invention the opaque regions are formed using frosted glass, but in alternative embodiments the opaque regions may be formed using paint, adhering an opaque material to the panels, or any other suitable means.

The panel unit includes sides 60. Sides 60 are C-shaped in cross section and extend from an outermost face of one static panel 12 to an outermost face of the other static panel 14. Lips of the sides 60 formed by the C-shape, form a perimeter around the outermost faces of the panel unit (as shown in Figure 1). The sides 60 encase the moveable panels 16, 18 in a region defined by the sides 60 and static panels 12, 14.

The sides 60 serve to prevent movement of the moveable panels 16, 18 in a non-desired direction, and in some embodiments may guide the moveable panels. In this embodiment, the sides 60 are made of metal, but in alternative embodiments any suitable material may be used.

In operation, to vary the visibility through the panel unit 10 one of the handles 32, 34 is rotated to rotate the shaft 30. Rotation of the shaft 30 causes the cams 26, 28 to push against a side of the aperture and actuate Unear movement of the moveable panels 16, 18. One of the movable panels 16, 18 will move in one direction, and the other moveable panel 16, 18 will move in the opposite direction. The casing 60 aids in restricting movement of the panels to only the desired directions (usually up and down, or eft and right). When the cams 26, 28 have be rotated through 90° the movable panels 16, 18 will be in a position that permits maximum or minimum visibility through the panel unit 10. Rotation of the handle 32 or 34 from this culTent position back to the start position will move the movable panels to be in the remaining position of minimum or maximum visibility through the panel.

In this embodiment, in the position of minimum visibility, visibility through the panel unit 10, at an angle of 90° to a plane defined by the panel unit 10, is completely obscured, In the position of minimum visibility, one of the opaque strips 44a of the movable panel 16 covers approximately half of one of the transparent strip 38a, 38b of the static panels 12, 14. The remaining approximate half of the transparent strip 38a, 38b of the static panel 12, 14 is covered by one of the opaque strips 44b of the moveable panel 18. Figure 12 illustrates one possiNe line of sight where limited visibility through the panel unit is possible even in the position of minimum visibility.

S However, the provision of opaque strips on both static panels reduces the range of angles of sight through which visibility through the panel is possible in the position of minimum visibility, compared to embodiments where opaque strips are only provided on one static panel.

In a position of maximum visibility, the opaque strips 44a, 44b of the moveable panels 16, 18 are positioned to be obscured from view behind the opaque strip 40a, 40b of the static panels 12, 14. Thus, a user can view through the panel unit through the transparent strips 38a, 38b of the static paneh 12, 14 and the substantially aligned and coincident transparent strips of the moveable panels 16, 18.

Advantageously, when the panel unit 10 is used in a vertical orientation, there is increased control of movement compared to panel units of the prior art because of a counterbalance provided by the concurrent movement of the moveable panels 16, 18 in opposite directions. Such counterbalance removes the need for additional dampers to be provided in the panel unit. Further, the counterbalance also enables larger moveable panels to be used than panel units of the prior art.

Two moveable panels 16, 18 having transparent strips of greater thickness than the opaque strips, and the same being provided on the static panels 12, 14 is advantageous because it permits, in a position of maximum visibility, increased visibility through the panel unit compared to panel units of the prior art. In some embodiments, visibility can be doubled.

Further, since the cams 26, 28 push against an edge of the aperturc 20, 22 there is increased flexibility over where the cams 26, 28 and apertures 20, 22 can be positioned. That is. a cam does not have to be at a lower edge of a moveable panel as with panel units of the prior art. Flexibility of where to position the cams 26, 28 results in flexibility of positioning of the handles 32, 34 to suit design requirements.

Referring to Figure 7, such flexibility of the position of the handle is particularly advantageous when the panel unit 10 is used as a full length panel in a door 52. It can be seen in this embodiment, the handle 32 (and 34, but not shown), is positioned in a central region of the door 52. This is a convenient location for an user. Such full length panels are not possible with panel units of the prior art because of weight issues of the panels, and in any case if they were possible the handle would need to be positioned in an inconvenient place (i.e. in a bottom region of the door).

The interaction of the cams 26, 28 with an edge of the apertures 20, 22 to move the moveable panels 16, 18, instead of relying completely or partly on gravity, is further advantageous because it permits the panel unit 10 to be used in an orientation such that the transparent and opaque strips are horizontal (as shown in the door of Figure 7). Mternativdy, the panel unit 10 can be used in an orientation such that the transparent and opaque strips are vertical, as illustrated in Figure 8, which shows a wall 54, including window 56 that includes the panel unit 10.

A further example of an application in which a panel unit 110 similar to the previously described panel unit 10 can be used is illustrated in Figure 9A. In this example, a door 158 includes the panel unit 110 in only an upper region of the door 158. In this embodiment, the handle 132 of the panel unit 110 is positioned in a lower region of the panel unit 110, so as to be in a convenient position for a user to operate the panel unit. A yet further example of use is illustrated in Figure 9B. In this example. the panel unit 110 is orientated in a door 158 so as to have the opaque and transparent strips arranged vertically instead of horizontally. It is envisaged that the panel unit may be positioned in a door or wall at any angle desired by an installer.

Although the invention has been described above with reference to one or more preferred embodiments, it will be appreciated that various changes or modifications may be made without departing from the scope of the invention as defined in the appended claims.

An example of an alternative embodiment is shown in Figure 10. Features similar to the features of the previously described embodiment are given similar reference numerals but with a prefix "2", and are not explained in detail again here. The panel unit 210 shown in Figure 10 differs from the panel unit 10 previously described in that it has a single moveable panel 216 instead of the two moveable panels 16, 18 previously described. As such there is also only a single cam 226, which is captive within an aperture 220 of the moveable panel 216. The panel 210 is beneficial because it can be used at any desired angle, and also because it is possible to position the cam and aperture, and therefore the handle, in a location most convenient for a user.

Similarly to previously described, the static panels 212, 214 include a transparent and opaque region, and the moveable panel 216 includes a transparent and an opaque region. However, in this embodiment the transparent and opaque regions are formed of transparent and opaque strips of substantially equal thickness. This is because, in this manner, the opaque strips of the nioveable panel 216 are capable of covering the transparent strips of the static panels to fully obscure visibility through the panel in a position of minimum visibility.

A further alternative embodiment is shown in Figure 11. Again, features similar to the features of the previously described embodiment are given similar reference numerals but with a prefix "3", and are not explained in detail again here. In this alternative embodiment, the static panels 312, 314 have an increased longitudinal length than the moveable panels 316, 318, and one of the moveable panels 316 is aiTanged at one longitudinal extent of the panel unit 310, and the other moveable panel 318 is arranged at the other longitudinal extent of the panel unit 310. For example, the panel unit 310 were used as a full length panel in a door, one of the moveable panels 316 would be in an upper region of the panel unit 310, and the other moveable panel 318 would be in a lower region of the panel unit 310.

The transparent and opaque regions of the static panels 312. 314 and the moveable panels 316, 318 differ from the transparent and opaque regions of the first described embodiment because the transparent and opaque regions comprise opaque and transparent strips of similar thickness. In this manner, similar to the panel unit 210 having a single moveable panel 216, one of the opaque strips of one of the moveable panels 316, 318 is capable of fully covering a transparent strip of one of the static panels 312, 314. In this embodiment, the moveable panel 316 in the upper region of the panel unit 310 is moveable to cover and uncover the transparent region in the upper region of the static panels 312, 314, and the moveable panel 318 in the lower region of the pand unit 310 is moveaNe to cover and uncover the transparent region in the lower region of the static panels 312, 314. In yet a further alternative, instead of S providing a single static panel 312, 314 extending the length of each side of the panel unit, two separate panels may be mounted in a casing of the panel unit; one static panel in an upper region and one static panel in a lower region. As with the first described embodiment, this arrangement benefits from increased control of movement compared to panel units of the prior art, because of a counterbalance provided by the concurrent movement of the moveable panels 316, 318 in opposite directions.

In another alternative embodiment, the transparent and opaque regions of the static and moveable pands may not include transparent and opaque strips, instead any suitable shape may be used, for example waves, circles, squares, triangles, or any other suitable pattern.

In yet another embodiment, the cams may not be captive in the apertures. In such alternative embodiments, the cams may only be partially within the apertures.

Further alternatively, there may not be an aperture and the cams may press against a lower edge of the moveable panels.

In yet a further alternative embodiment, the cam may not be a rotary cam and instead be a linear cam. For example, the cam may be a linear slot (i.e. an aperture) and a follower may move within the linear slot that has a horizontal (stable) upper region and a horizontal (stable) lower region connected by a diagonal cam track. When the panel unit has two moveable panels the upper and lower regions of the slots may be directionally opposed, such that the diagonal tracks form an X shape when superimposed.

It is also envisaged that the cam track may not be formed in the moveable panel, and instead the follower may be connected to the moveable panel and the follower formed in, for example, a carriage located in the region of the cam.

Claims

Claims 1. A panel unit having selectively variable visibility therethrough. the panel unit comprising: a static panel having a transparent region and an opaque region; a moveable panel positioned substantially parallel to the static panel and having a transparent region alignable with the transparent region of the static panel for maximum visibility through the panel unit, and an opaque region alignable with the transparent region of the static panel for minimum visibility through the panel unit; a cam and follower alTangement connected to the moveable panel, wherein the cam and foflower arrangement comprises two foflowers and a cam, one of the followers being configured to interact with the cam so as to linearly move the moveable panel relative to the static panel in one direction, and the other follower being configured to interact with the cam so as to linearly move the moveable panel relative to the static panel in an opposite direction, so as to vary the visibility through the panel unit.
2. The panel unit according to claim 1, wherein the cam and follower arrangement comprises an aperture, and one of the followers is defined by one surface of the aperture and the other follower is defined by another surface of the aperture.
3. The panel unit according to claim 2, wherein the cam is captive within the aperture.
4. The panel unit according to claim 2 or 3, wherein the aperture is formed in the moveable panel, and the cam is positioned within the aperture.
5. The panel unit according to claim 4, wherein the cam is a rotary cam and rotation thereof contacts an edge of the aperture to move the moveable panel.
6. The panel unit according to claimS, wherein the aperture is substantially rectangular shaped with a stepped corner, such that an edge of the aperture defines one follower and the stepped corner defines the other follower.
7. The panel unit according to any one of the previous claims comprising: a further moveable panel having a transparent region alignable with the transparent region of the static pand, and an opaque region alignable with the transparent region of the static panel; a further cam and aperture arrangement connected to the further moveable panel and configured to interact so as to linearly move the further moveable panel relative to the static panel.
8. The panel unit according to claim 7, wherein the further cam is fixed relative to and connected to the cam.
9. The panel unit according to claim 8, wherein the cam and the further cam are rotary cams.
10. The panel unit according to any one of claims 7 to 9, wherein the moveable panel and further moveaNe panel are positioned such that the transparent regions of the moveable panel and further moveable panel are alignable with the transparent region of the static panel, and the opaque regions of the moveable panel and further movable panel are each configured to partially cover the same transparent region of the static panel.
11. The panel unit according to claim 10, wherein the transparent region of the static panel, moveable panel and further moveable panel covers an area up to 180 -200% of the area covered by the opaque region of said panels.
12. The panel unit according to any one of the previous claims comprising a handle connected to an actuator for causing interaction of the cain and follower.
13. The panel unit according to any one of daims I to 12, wherein the cam is positioned in a central region of the panel unit.
14. The panel unit according to any one of daims I to 12, wherein the cam is positioned in a lower region of the panel unit, to one side of the panel unit, or in an upper region of the panel unit.
15. The panel unit according to any one of the previous claims, wherein the opaque and transparent regions of the panels comprise a plurality of linear strips extending across said panel, and the moveable panel is linearly moveable in a direction perpendicular to the direction of the strips.
16. The panel unit according to any one of the previous claims comprising a further static panel, the static and further static panel being positioned on outermost sides of the panel unit, such that the moveable panel is positioned therebetween.
17. A door comprising a window formed using the panel unit according to any one of the previous claims.
18. The door according to claim 17, wherein the length of the window extends at least 50% of the height of the door.
19. The door according to claim 17, wherein the length of the window extends less than 50% of the height of the door
20. A window formed using the panel unit according to any one of claims I to 16.
21. A panel unit having selectivdy variable visibility therethrough. the panel unit comprising: a static panel having a transparent region and an opaque region; a first moveable panel positioned substantially parallel to the static panel and having a transparent region alignable with the transparent region of the static panel, and an opaque region alignable with the transparent region of the static panel; a second moveable panel positioned substantially parallel to the static panel and the first moveable panel and having a transparent region alignable with the transparent region of the static panel, and an opaque region alignable with the transparent region of the static panel; and two cams, one cam being positioned for actuating the first moveable panel, and the other cam being positioned for actuating the second moveable panel; wherein the two cams are connected to each other, and fixed relative to each other, such that movement of the two cams causes the first and second moveaWe panels to move linearly in opposite directions.
22. The panel unit according to claim 21, wherein the two cams are rotary cams.
23. The panel unit according to claim 22, wherein the two cams are arranged substantially perpendicular to each other.
24. The panel unit according to any one of claims 21 to 23, wherein the first and second moveable panels are positioned such that the transparent regions of the first and second moveable panel are alignable with the transparent region of the same static panel, and the opaque regions of the first and second movable panels are each configured to partially cover the same transparent region of the static panel.
25. The panel unit according to claim 24, comprising an aperture formed in the first and second moveable panels; and wherein one of the two cams is positioned within each aperture and configured to contact an edge of the respective aperture to move the first and second moveable panels.
26. The panel unit according to claim 25, wherein the aperture is substantially rectangular shaped with a stepped corner.
27. A panel unit substantially as hereinbefore described with reference to and/or as shown in the accompanying drawings.
28. A door substantially as hereinbefore described with reference to and/or as shown in the accompanying drawings.
29. A window substantially as hereinbefore described with reference to and/or as shown in the accompanying drawings.