FIELD OF THE INVENTION

[0001] The present invention relates to window blinds, in particular a blockout blind system suitable for use with existing roller blinds.

BACKGROUND TO THE INVENTION

[0002] Blockout blinds are used to block all or nearly all light from entering through a window and are often considered a necessity for shift workers. They are also becoming an increasingly popular addition to home cinemas.

[0003] To date, effective blockout systems have required removal of existing blinds and replacement with purpose made components. Quite often the existing blinds are in good order and sometimes even brand new. The discarding of existing blinds is an undesirable environmental and cost burden.

[0004] In achieving an effective blockout of light, known systems also achieve the undesired result of blocking close to 100% of airflow. This is problematic in airconditioned environments when there is an air leak around the window as the pressure differential between either side of the blinds can cause the blind being pushed or sucked out of its frame. In buildings with evaporative air conditioning systems it is undesirable to have no external ventilation.

[0005] Existing roller blinds are usually operated by a chain which hangs down from the top of the blind, presenting a strangulation hazard to children and animals.

[0006] The object of this invention is to provide a blockout blind system to alleviate the above problems, or at least provide the public with a useful alternative.

SUMMARY OF THE INVENTION

[0007] In a first aspect the invention provides a blockout blind system comprising a roller blind and side tracks, wherein the side tracks comprise a first channel for accepting the blind and wherein the first channel is fitted with first and second brushes to prevent light passing past the blind.

[0008] Preferably the first and second brushes comprise apertures, and wherein the apertures of the first brush are vertically displaced with respect to the apertures of the second brush.

[0009] Preferably the system includes a pelmet and the pelmet is fitted with a series of flaps to prevent light passing past the blind.

[0010] In preference the series of flaps comprise first and second inner flaps which drape over either side of the blind, and the first and second inner flaps comprise apertures which are horizontally displaced with respect to each other.

[0011 ] Preferably the series of flaps further comprises first and second outer flaps, which hang spaced apart from either side of the blind.

[0012] The side tracks may further comprise a second channel for accepting a chain of the roller blind. The system may also comprise a handle for manipulating the chain within the second channel, or the system may also comprise a sprocket in the second channel for manipulating the chain, the sprocket being driven by a handle.

[0013] Preferably the system further comprises a bottom rail adapted to accept a bottom rail of the roller blind, and the bottom rail includes ends which sit within the first channels of the side tracks.

[0014] It should be noted that any one of the aspects mentioned above may include any of the features of any of the other aspects mentioned above and may include any of the features of any of the embodiments described below as appropriate.

BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Preferred features, embodiments and variations of the invention may be discerned from the following Detailed Description which provides sufficient information for those skilled in the art to perform the invention. The Detailed Description is not to be regarded as limiting the scope of the preceding Summary of the Invention in any way. The Detailed Description will make reference to a number of drawings as follows.

[0016] Figure 1 shows a window with an existing blind to which the blockout system of the present invention can be fitted. [0017] Figure 2 shows the existing blind with the blockout system of the present invention fitted.

[0018] Figure 3 shows a cross section view of the side track of the system.

[0019] Figure 4 shows a perspective view of the side track in use with a blind fitted.

[0020] Figure 5 shows a cross section side view of the pelmet of the system.

[0021] Figure 6 shows a perspective view of the pelmet fitted with a blind, light blocking flaps, and light blocking brush.

[0022] Figure 7A shows the cross rail of the system; Figure 7B shows the cross rail fitted with a blind.

[0023] Figure 8A shows a specialised handle for engaging the chain of the blind; Figure 8B shows the handle engaged with the chain.

[0024] Figure 9 shows an alternative implementation of the handle.

DRAWING COMPONENTS

[0025] The drawings include the following integers.

10 window space

12 wall

20 roller blind

21 tube

22 blind

23 bottom bar

26 chain

27 string

28 beads

30 blockout system

40 side track

41 blind channel

42 rear wall

43 middle wall

44 step 45 blind brushes

46 brush holders

50 chain channel

51 front wall

52 side wall

53 side brush

54 brush holder

55 tensioner channel

60 pelmet

61 front wall

62 top wall

63 flap holders

64 top brush

65 brush holder

70 outer flaps

71 air gap

72 sealing flaps

80 cross rail

81 cavity

82 blind slot

83 bottom brush

84 brush holder

85 weighted section

90 handle

91 offset end

92 channels

93 slot

99 angled handle

DETAILED DESCRIPTION OF THE INVENTION

[0026] The following detailed description of the invention refers to the accompanying drawings. Wherever possible, the same reference numbers will be used throughout the drawings and the following description to refer to the same and like parts. Dimensions of certain parts shown in the drawings may have been modified and/or exaggerated for the purposes of clarity or illustration.

[0027] The present invention provides a blockout blind system that can be used with conventional roller blinds, making it suitable for both new and retrofit applications. Side tracks fitted with brushes in conjunction with a pelmet fitted with flaps ensure virtually no light can pass around the blind. The flaps and brushes have offset apertures either side of the blind to allow for airflow thus preventing the blind being sucked out or pushed in by open or leaking windows and air conditioning systems. The system also conceals the chain for operating the blind thus eliminating strangulation hazards for children and animals.

[0028] Figure 1 shows a window space 10 in a wall 12 fitted with a roller blind 20 as is well known in the art. The roller blind 20 includes a tube 21 around which a blind 22 is wound. The blind includes a bottom bar 23 to help it hang neatly. The blind is supported by brackets and includes a sprocket (not shown) at the end of the tube driven by chain 26 to lower or raise the blind. The chain 26 comprises a string 27 passing through a series of regularly spaced beads 28 (seen in detail in Figure 8A). A chain tensioner, typically another sprocket, may be fitted to the bottom of the chain to hold it taut thus allowing either side of the chain to both raise or lower the blind.

[0029] Figure 2 shows the window space and blind as in Figure 1 , but now fitted with a blockout blind system 30 according to the present invention. The figure serves to identify the context of the various major elements of the system without showing their details. The system comprises side tracks 40 which provide a light seal to the sides of the blind, a pelmet 60 which provides a light seal to the top of the blind, and a cross rail 80 which envelopes the bottom bar of the blind and provides a light seal for the bottom of the blind when fully closed. The side tracks and pelmet include features to allow air flow around the blind whilst blocking light.

[0030] A top view of the side track 40 is shown in Figure 3, whilst details of the side track and how it engages with the blind 22 can be seen in the perspective view of Figure 4. The side track comprises two main elements, a blind channel 41 for accepting the blind 22 defined by rear wall 42 and middle wall 43, and a chain channel 50 for containing the front of the chain 26 defined by the middle wall 43 and a front wall 51 . The rear, middle and front walls all extend from a side wall 52 which sits against the side of the window space 10. A side brush 53 sits within brush holder 54 to seal any potential light gaps. Tensioner channel 55 provides clearance for a chain tensioner (not shown) to be fitted at the lower end of the chain 26. To allow the chain 26 to pass from the chain channel 50 around the tensioner and behind the side track, a small amount of material is removed from the bottom of the side track. The chain channel is approximately 25 mm deep and 6 mm wide to deny finger access to the chain but allow the chain to be operated with a special handle 90 as discussed below with the aid of Figures 8A and 8B. The middle wall 43 includes a step 44 so that the handle 90 doesn’t rub against and potentially scratch the visible portion of the middle wall. The blind channel 41 includes blind brushes 45 held by brush holders 46 which provide a light seal against the front and rear of the blind 22. The brushes have apertures (not shown) to allow some airflow around the blind. To prevent light also passing around the blind, the apertures of the front and rear brushes are vertically offset from each other.

[0031] A side view of a pelmet 60 is shown in Figure 5, whilst Figure 6 shows a cutaway view of the pelmet with a roller blind 20 fitted detailing how the pelmet provides a light seal at the top of the blind. The pelmet 60 comprises a front wall 61 to help with blocking light and to also hide the inner features of the pelmet, and a top wall 62 from which a series of flaps are suspended from holders 63 to prevent light from passing over the top of the blind. The top wall 62 sits against the top of the window space 10 and includes a top brush 64 sitting within brush holder 65 to seal any potential light gaps. Outer flaps 70 hang vertically either side of the blind leaving an airgap 71 . Inner flaps 72 lie against the blind. To allow some airflow over the top of the blind the inner flaps include apertures (not shown). The apertures of the two inner flaps are horizontally offset from each other to prevent light passing through. The front wall of the pelmet together with the four flaps provide an effective light seal whilst still allowing some airflow.

[0032] To provide a light seal at the bottom of the blind, the bottom bar 23 of the blind 22 is held within the cross rail 80. Figure 7A shows a cross rail in isolation whilst Figure 7B shows the blind fitted to the cross rail. The cross rail includes a cavity 81 to accommodate the bottom bar 23 and a narrow slot 82 for the blind to pass through. Brush 83 sitting in holder 84 provides a light seal on the underside of the cross rail when the blind is fully down. The cross rail is approximately 10 mm deep allowing its sides to sit within the correspondingly sized blind channels 41 of the side tracks 40. To help the blind move downwards smoothly the cross rail includes a weighted section 85. The bottom bar 23 is trimmed at its end so that when the cross rail sits within the blind channel 41 , the blind 22 can extend through the brushes 45 fitted to the blind channel (as per Figure 4). End caps (not shown) are fitted to the blind bar to prevent scratching of, and allow smooth movement in, the blind channel.

[0033] To access the chain 26 in the chain channel 50 a handle 90 as shown in Figure 8A and 8B is used. The handle includes an offset end section 91 with a series of channels 92 shaped and spaced to engage with the beads 28 of the chain. The offset provides clearance for fingers between the handle and the blind. Slot 93 accepts the string 27 between the beads thereby allowing the beads to sit completely within the end of the handle. This allows the end of the handle to sit against the inside of the side wall 52 thus eliminating any drag of the beads against the side wall as the handle is moved. Moving the handle up and down will correspondingly move the chain and thus extend or retract the blind as desired. An alternative implementation of the handle is shown as 99 in Figure 9 in which the end section is at an angle to the main body of the handle to keep the main body clear of the blind and provide finger room.

[0034] Instead of using the handles of Figures 8 or 9 to manipulate the chain, a chain sprocket can be fitted to the chain channel 50 of the side track to engage the chain. Preferably the sprocket is positioned close to the inside of the side wall 52 to trap the chain in order to eliminate the chance of chain slippage. The sprocket is driven by a small handle which may be made removable if desired.

[0035] The side track, pelmet and cross rail are preferably made from extruded aluminium powder coated in various colours. The flaps fitted to the pelmet are preferably of a conventional blind material, again in matt black to minimise reflection of light.

[0036] The above disclosure has described a blockout blind system that can be used with conventional roller blinds, making it suitable for both new and retrofit applications. Side tracks fitted with brushes in conjunction with a pelmet fitted with flaps ensure no light can pass around the blind. The flaps and brushes have offset apertures either side of the blind to allow for airflow thus preventing the blind being sucked out or pushed in by open or leaking windows and air conditioning systems. The system also conceals the chain for operating the blind thus eliminating choking hazards for children and animals.

[0037] The system described has many features that when combined blockout light very effectively, possibly even by 100%. Not all applications require 100% blockout and sometimes people even prefer a small degree of light leakage. In such applications the side tracks alone may achieve the desired result, or the side tracks in combination with a simple pelmet without the additional flaps, or perhaps with a pelmet with 1 , 2 or 3 of the flaps.

[0038] Further advantages and improvements may very well be made to the present invention without deviating from its scope. Although the invention has been shown and described in what is conceived to be the most practical and preferred embodiment, it is recognized that departures may be made therefrom within the scope of the invention, which is not to be limited to the details disclosed herein but is to be accorded the full scope of the claims so as to embrace any and all equivalent devices and apparatus. Any discussion of the prior art throughout the specification should in no way be considered as an admission that such prior art is widely known or forms part of the common general knowledge in this field.

[0039] In the present specification and claims (if any), the word "comprising" and its derivatives including "comprises" and "comprise" include each of the stated integers but does not exclude the inclusion of one or more further integers.