GB2405661A

GB2405661A - Assisted roller blind mechanism

Info

Publication number: GB2405661A
Application number: GB0320910A
Authority: GB
Inventors: Peter Braybrook
Original assignee: Levolux AT Ltd
Current assignee: Levolux AT Ltd
Priority date: 2003-09-06
Filing date: 2003-09-06
Publication date: 2005-03-09
Also published as: GB0320910D0

Abstract

An assisted roller blind mechanism 10 comprising an urging unit 12 insertable in an elongate blind material holder tube of a roller blind, and an adjustment mechanism 14 positioned at one end of the urging unit 12. The urging unit 12 has an urging element 16 which can be held stationary at one point relative to the holder tube so that, in use, torsion can be imparted to the urging element 16 using the adjustment mechanism 14 without necessitating removal of the roller blind from a supporting bracket 70. The adjustment mechanism may comprise a ratchet mechanism allowing the adjustment to rotate in one predetermined but selectable direction only.

Description

240566 1

ASSISTED ROLLER BLIND MECHANISM

This invention relates to an assisted roller blind mechanism.

Assisted roller blind mechanisms are known. Typically, these incorporate a coiled spring mechanism to assist in raising of the blind. However, simple balancing of the blind, so that the spring of the spring assist mechanism is set to the correct or preferred torsion, has long been a problem.

At present, to adjust the spring of known spring assist mechanisms, one end of the roller blind must be detached from its support bracket. The spring is wound or twisted to impart a degree of torsion. The roller blind is re-connected with the support bracket, and the blind is tested. This process is repeated until the spring assist mechanism is correctly set. This method is time consuming and problematic, particularly with larger blinds, which are cumbersome to adjust due to their weight and size, and a series of blinds where it is preferable that all the blinds operate uniformly or substantially uniformly.

It is also particularly troublesome to impart any fine adjustment to the assist mechanism using the known method and arrangement, and this causes difficulties for designers and architects striving to achieve smooth and effortless operation within their designs.

The present invention seeks to overcome these difficulties and problems.

According to a first aspect of the present invention, there is provided an assisted roller blind mechanism comprising an urging unit insertable in an elongate blind material holder tube of a roller blind, and an adjustment mechanism positioned at one end of the urging unit, the urging unit having an urging element which can be held stationary at one point relative to the holder tube so that, in use, torsion can be imparted to the urging element using the adjustment mechanism without necessitating removal of the roller blind from a supporting bracket.

Preferable and/or optional features of the first aspect of the invention are set forth in claims 2 to 10, inclusive.

According to a second aspect of the invention, there is provided a roller blind having an assisted blind mechanism in accordance with the first aspect of the invention.

Preferably, the blind is a free-fall blind. The application of an assist mechanism to a free-fall blind results in a blind having straightforward gravity assisted unfurling and simple take-up assisted by the assisted blind mechanism.

According to a third aspect of the invention, there is provided a method of assembling a roller blind having an assisted roller blind mechanism in accordance with the first aspect of the invention, the method comprising the steps of: a) fastening roller blind support brackets to a supporting surface; b) locating the urging unit in one end of the elongate blind material holder tube so that the urging element is fixed at one point relative to the holder tube; c) engaging the adjustment mechanism with the end of the urging unit; and d) locating one end of the holder tube in one of the support brackets and the adjustment mechanism in another of the support brackets.

Preferably, the method further comprises a step (e)' subsequent to step (b) and prior to step (c), of selecting which direction the adjustment mechanism is rotatable to impart torsion to the urging element so that winding of the blind is assisted.

According to a fourth aspect of the invention, there is provided a method of balancing a roller blind having an assisted roller blind mechanism in accordance with the hrst aspect of the invention, the method comprising the steps of: a) unfurling the blind to the maximum required fall; and b) operating the adjustment mechanism of the assisted roller blind mechanism to impart torsion to the urging element with the roller blind supported in its supporting brackets.

Preferably, the method further comprises a step (c), subsequent to step (a) and prior to step (b), of disengaging the roller blind from one supporting bracket to release undesirable torsion in the urging element imparted due to unfurling the blind in step (a), and then re-engaging the roller blind with the supporting bracket.

The method may further comprise a step (d) subsequent to step (b) of disengaging the roller blind from one supporting bracket to release torsion in the urging element when excessive torsion is applied through the adjustment mechanism, then re-engaging the roller blind with the supporting bracket and repeating step (b).

This enables a quick release of imparted torsion, allowing winding or twisting to be re-started.

The invention will now be more particularly described, by way of example only, with reference to the accompanying drawings, in which: Figure I is an exploded view of an assisted roller blind mechanism, in accordance with the first aspect of the present invention; and Figure 2 is an enlarged exploded view of an adjustment mechanism of the assisted blind mechanism, shown in Figure 1.

Referring now to the drawings, there is shown an assisted roller blind mechanism 10 which comprises a spring urging unit 12 and an adjusunent mechanism 14. The urging unit 12 has an elongate metal coil spring 16, a keying element 18 engaged with and projecting from one end of the spring 16, an axle 20 on which the spring 16 is positioned and to which the other end of the spring 16 is fixed, and a bush element 22 which supports the axle 20 for rotation.

The keying element 18 is shaped to provide a base plate 24 which has an external diameter in excess of the normal external diameter of the coil spring 16 and slightly less then the internal diameter of a roller blind material holder tube (not shown) in which it is intended to reside. The circumference of the base plate 24 is notched to enable keying to a radially inwardly projecting rib formed on the said blind material holder tube. Two teeth 26 are also formed on the circumference of the base plate 24 to promote gripping when in use.

A frusto-conical spigot 28 projects from the base plate 24 of the keying element 18, and a groove 30 is formed around the base of the spigot 28 adjacent the base plate 24. The maximum diameter of the spigot 28 is larger than the normal internal diameter of the spring 16. One end of the spring 16 is thus pressed or wound onto the spigot 28 until the end of the spring 16 locates in the groove 30. This effectively locks the keying element 18 and the spring 16 together.

The axle 20 is generally cylindrical and the end portion 32 of the axle 20, nearest the keying element 18, has an external diameter which is slightly larger than the normal internal diameter of the spring 16. As with the keying element 18, the other end of the spring 16 is wound onto the axle 20 as an interference fit. A pin (not shown) is inserted diametrically through the axle 20 and between coils of the spring 16 to prevent or inhibit slippage of the spring 16 along the axle 20.

The other end of the axle 20 sits in the bush element 22. The bush element 22 is typically formed from plastics, but may be metal, and a major portion 34 is dimensioned to locate in the blind material holder tube as an interference push fit. The bush element 22 is formed with a lip 36 at one end adjacent the end of the axle 20 not engaged with the spring 16. The lip 36 forms a shoulder against which the end of the blind material holder tube can abut.

The adjustment mechanism 14 comprises an adjustment member 38 and a ratchet mechanism 40. The adjustment member 38 is typically formed of metal, such as alloy, or plastics, and consists of an adjustment disk 42 which, in this case, has a castellated circumference, a plurality of radially extending openings 44 formed equi angularly around and equidistantly spaced from the centre of the disk 42, and a spigot element 46 push fit insertable into an aperture 48 formed through the centre of the disk 42. The diameter of the disk 42 is equal to, or greater than, the external diameter of the blind material holder tube.

The spigot element 46 has a square shaped head 50 to fit the square shaped centre aperture 48 in the disk, and a cylindrical hub 52 engageable for rotation with the ratchet mechanism 40.

The ratchet mechanism 40 consists of a base plate 54 having a centre recess 56 and a plurality of ratchet recesses 58 formed equi-angularly around and equi-distantly spaced from the centre recess 56, two ratchet elements 6O, and a non-circular locating spigot 62 formed on the base plate 54 opposite the ratchet recesses 58.

The ratchet mechanism 40 is formed of plastics material, but could be metal or a combination of materials. Each ratchet element 60 has an outwardly sprung slopping tongue 64, and the ratchet recesses 58 are dimensioned to receive the ratchet elements so that the free-edge of each ratchet element tongue 64 projects above the outer edge of the respective ratchet recess 58.

It will be understood that only one ratchet element 60, or more than two ratchet elements 60, may be provided.

The centre recess 56 is cylindrical and shaped to rotatably receive the hub 52 of the spigot element 46 of the adjustment member 38.

When the adjustment mechanism 14 is assembled, the slopping tongue 64 of each ratchet element 60 locates in one of the radially extending openings 44 of the adjustment disk 42. Consequently, the adjustment disk 42 can only be rotated in one direction.

The head 50 of the spigot element 46 of the adjustment member 38 is formed with an opening 66 to receive the end 68 of the axle 20 of the urging unit 12. The head opening 66 and the axle end 68 are complementarily shaped and dimensioned to form an interference fit when engaged. With the assisted blind mechanism 10 assembled, therefore, the adjustment mechanism 14 is connected to the spring 16 via the axle 20.

To assemble and install a roller blind having the above-described assisted blind mechanism 10, it is first decided which end of the roller blind material holder tube the adjustment mechanism 14 should be placed, for example taking into account ease of accessibility. The roller blind supporting members, in this case brackets 70, are then mounted on the desired blind supporting surface. The roller blind supporting bracket intended to support the locating spigot 62 has a complementarily shaped non circular recess (not shown). This prevents rotation of the locating spigot 62 when seated in the recess of the supporting bracket 70.

The directional orientation of the ratchet elements 60 depends on which end the assisted blind mechanism 10 is to be installed.

The ratchet elements 60 are seated in the ratchet recesses 58 of the ratchet mechanism 40 in the direction which will allow the greatest degree of torsion to be imparted to the spring 16 when the blind is unfurled. The spigot element 46 is located in the centre aperture 48 of the adjustment disk 42, and then the hub 52 of the spigot element 46 is pushed into the centre recess 56 in the base plate 54 of the ratchet mechanism 40.

The spring 16 of the urging unit 12 is then inserted into the end of the roller blind material holder tube at which the adjustment mechanism 14 will be located. The keying element 18 is keyed to the internal rib of the holder tube and the spring 16 is slid into the holder tube followed by the axle 20 and bush element 22. The bush element 22 is pushed home so that the edge of the holder tube abuts the lip 36 of the bush element 22.

The adjustment mechanism 14 is then engaged with the end of the urging unit 12 by inserting the end 68 of the axle 20 projecting from the bush element 22 into the opening 66 of the head 50 of the spigot element 46 of the adjustment member 38.

The roller blind also has a blind winding unit (not shown) which, in this embodiment, is located at the end of the holder tube opposite the assisted blind mechanism 10.

The assembled roller blind can then be offered into position with the locating spigot 62 of the ratchet mechanism 40 being located in one supporting bracket 70 and a locating spigot on the blind winding unit being located in the other supporting bracket.

To balance the roller blind once it is installed, the blind is simply unfurled to the maximum required fall, any imparted torsion in the spring 16 of the spring urging unit 12 is initially released by disengaging the locating spigot 62 briefly from the support bracket 70, the locating spigot 62 is re-engaged with the support bracket, and then the adjustment disk 42 is turned by a user. Turning the adjustment disk 42 causes rotation of the axle 20 of the urging unit 12, which in turn winds or twists the spring 16. Thus, the user determines the amount of torsion imparted to the spring 16.

If a mistake is made and too much torsion is imparted to the spring 16, the torsion is simply released by disengaging the locating spigot 62 from the supporting bracket 70. The locating spigot 62 is then re-engaged with the supporting bracket 70, and adjustment is re-started. s

As can be understood, the ratchet mechanism 40 is essential to prevent or limit torsion imparted to the spring back-driving the adjustment mechanism 14.

In use, torsion imparted to the spring 16 is transmitted to the keying element 18, thereby imparting a turning moment on the blind holder tube. The magnitude of the imparted torsion is typically set to be sufficiently small to prevent the holder tube from turning without user initiation. As a consequence, gravity, partially offset by the torsion in the spring 16, will hold the blind at a user determined unfurled or partially unfurled position, and the assisted blind mechanism 10 will aid in the winding when the blind is raised by the user.

The type of coil spring may be chosen to suit certain types of blind. For example, those blinds with a large drop may require a spring which can accept a larger degree of torsion with fewer turns of the adjustment disk.

It is also not a necessity that a coil spring urging unit be used, and any type of urging unit which can fit a blind material holder tube and which can impart a turning moment when torsionally charged could be used. For example, the spring could be replaced by a rubber element or any other type of urging element of any suitable material.

Although the spring is separately positioned on the axle of the urging unit and the keying element is engaged with the end of the spring, the spring or urging element could be formed integrally as part of the urging unit.

The or each ratchet element could be integrally formed as part of the base plate of the ratchet mechanism, and the spigot element could be integrally formed as part of the adjustment disk. The openings in the adjustment disk may be through-openings or simply recesses in one surface. Ratchet elements could be positioned on the base plate and the adjustment disk, and in this case would engage on each other to prevent reverse driving. The ratchet elements could also be positioned solely on the adjustment disk, with the openings being formed in the base plate of the ratchet mechanism.

The circumference of the adjustment disk may have formations other than castellation, and may be provided with a depending adjustment element, such as a chain or rod, to allow a user, standing on the floor, to easily adjust the torsion in the spring or urging element.

The blind winding unit may be incorporated as part of the urging unit. In this case, the blind winding unit is located at the same end of the holder tube as the adjustment mechanism.

The spring or urging element of the present invention could be torsionally charged, through use of the adjustment mechanism, to wind up the blind without user assistance, when the blind is released by a user. In this case, the unfurled blind would have to be held in an unfurled position. s

A tool could be used to operate the adjustment disk, rather than the disk being operated directly by the hand of a user.

The holder tube could be integrally formed with a bearing surface on which the inserted axle of the urging unit rides. In this case, the bush element could be dispensed with.

The assisted blind mechanism described above could be used in conjunction with known decelerator devices.

The assisted blind mechanism is particularly appropriate for use with a free-fall type blind which unfurls under gravity. Predetermined stops can be incorporated into the blind winding mechanism so that the blind can be held at predetermined positions.

The use of the above-described assisted blind mechanism is of particular benefit in a series of free-fall type blinds, where smoothness and uniformity of operation is paramount.

It is thus possible to provide an assisted blind mechanism which enables quick and simple balancing of a blind without requiring removal of the blind from its t supporting brackets during balancing. It is also possible to provide an assisted blind mechanism which permits uncomplicated fine adjustment of the torsion imparted to the spring unit or urging unit of the assisted blind mechanism.

The embodiments described above are given by way of example only and modifications will be apparent to persons skilled in the art without departing from the scope of the invention as defined by the appended claims.

Claims

1. An assisted roller blind mechanism comprising an urging unit insertable in an elongate blind material holder tube of a roller blind, and an adjustment mechanism positioned at one end of the urging unit, the urging unit having an urging element which can be held stationary at one point relative to the holder tube so that, in use, torsion can be imparted to the urging element using the adjustment mechanism without necessitating removal of the roller blind from a supporting bracket.

2. An assisted blind mechanism as claimed in claim 1, wherein the urging unit further comprises a bush element which is positionable at or adjacent to one end of the holder tube so as to be held stationary relative to the holder tube and which is rotatable relative to the urging element as the blind is wound or unfurled.

3. An assisted blind mechanism as claimed in claim 1 or claim 2, wherein the adjustment mechanism comprises an adjustment member and a ratchet mechanism which allows the adjustment member to rotate in one predetermined direction only.

4. An assisted blind mechanism as claimed in claim 3, wherein the ratchet mechanism comprises a base plate, one or more ratchet elements on the base plate, and a plurality of openings formed in the adjustment member, the or each ratchet element comprising an outwardly sprung tongue which is locatable in one of the openings in the adjustment member to prevent or limit back-driving of the adjustment member.

5. An assisted blind mechanism as claimed in claim 4, wherein the orientation of the or each ratchet element on the base plate is selectable, so that the assisted blind mechanism can be located at either end of the roller blind.

6. An assisted blind mechanism as claimed in any one of claims 3 to 5, wherein the urging element of the urging unit is, at least in use, directly or indirectly connected to the adjustment member of the adjustment mechanism to enable winding or twisting of the urging element.

7. An assisted blind mechanism as claimed in claim 7, wherein the urging element is an elongate coil spring. i

8. An assisted blind mechanism as claimed in any one of claims 3 to 7, wherein the adjustment member comprises an adjustment disk for operation of the adjustment mechanism by a user.

9. An assisted blind mechanism as claimed in any one of the preceding claims, further comprising a blind winding unit for at least winding the roller blind, the blind winding unit being located on or adjacent to the urging unit.

10. An assisted blind mechanism as claimed in claim 9, wherein the blind winding unit is formed as part of the urging unit.

11. An assisted blind mechanism substantially as hereinbefore described with reference to the accompanying drawings.

12. A roller blind having an assisted blind mechanism as claimed in any one of the preceding claims.

13. A roller blind as claimed in claim 12, wherein the blind is a freefall blind.

14. A method of assembling a roller blind having an assisted roller blind mechanism as claimed in any one of claims 1 to 11, the method comprising the steps of: a) fastening roller blind support brackets to a supporting surface; b) locating the urging unit in one end of the elongate blind material holder 1S tube so that the urging element is fixed at one point relative to the holder tube; c) engaging the adjustment mechanism with the end of the urging unit; and d) locating one end of the holder tube in one of the support brackets and the adjustment mechanism in another of the support brackets.

15. A method as claimed in claim 14, further comprising a step (e), subsequent to step (b) and prior to step (c), of selecting which direction the adjustment mechanism is rotatable to impart torsion to the urging element so that winding of the blind is assisted.

16. A method of balancing a roller blind having an assisted roller blind mechanism -S as claimed in any one of claims 1 to 11, the method comprising the steps of: a) unfurling the blind to the maximum required fall; and b) operating the adjustment mechanism of the assisted roller blind mechanism to impart torsion to the urging element with the roller blind supported in its supporting brackets.

17. A method as claimed in claim 16, further comprising a step (c), subsequent to step (a) and prior to step (b), of disengaging the roller blind from one supporting bracket to release undesirable torsion in the urging element imparted due to unfurling the blind in step (a), and then re-engaging the roller blind with the supporting bracket.

18. A method as claimed in claim 16 or claim 17, further comprising a step (d) subsequent to step (b) of disengaging the roller blind from one supporting bracket to release torsion in the urging element when excessive torsion is applied through the adjustment mechanism, then re- engaging the roller blind with the supporting bracket and repeating step (b).