GB2199065A

GB2199065A - Roller blinds

Info

Publication number: GB2199065A
Application number: GB08629187A
Authority: GB
Inventors: Long-Po Ho
Original assignee: Individual
Current assignee: Individual
Priority date: 1986-12-05
Filing date: 1986-12-05
Publication date: 1988-06-29
Also published as: GB8629187D0

Abstract

A roller blind mechanism including a roller (13), and retracting spring (20) has a device (14) for latching the roller (13) in a selected blind extended condition. The latching device (14) comprises an outer rotor 18, 39 rotating with the roller (13), an inner fixed stator (16, 17, 22) and at least one latching member (19) between the stator (22) and the rotor (39). The latching member is held captive with respect to a pocket (45) in the rotor (39) and the stator (22) has a cam surface (24) followed by the latching member as the rotor is turned in the blind extend direction, when the blind is retracted slightly a member 19 jams in the upper detent 25 to hold the blind. The latching member (19) moves centrifugally into the pocket (45) when the blind is raised rapidly. <IMAGE>

Description

Roller Blinds This invention relates to a roller blind.

Known roller blind mechanisms suffer from the drawback that they are not consistent in operation in the sense that they do not always operate as required to latch the blind in a desired extended condition.

The present invention seeks to provide a roller blind mechanism which overcomes the drawbacks of the prior art.

According to the invention there is provided a roller blind mechanism comprising a roller, means for supporting the roller for rotation between a blind retracted condition and a blind extended condition, spring means urging the roller towards a blind retracted condition, and a latching device for latching the roller in a selected blind extended condition, said latching device comprising an outer rotor mounted for rotation with the roller, an inner stator within the rotor, the stator being fixed relative to said supporting means, and at least one latching member between the stator and the rotor, the latching member being held captive with respect to a pocket in the rotor and the stator having a cam surface shaped so that the latching member will pass over the cam surface and move inwards and outwards of said pocket as the rotor is turned in an angular direction to extend the blind and so that the latching member will engage the cam surface when the rotor is allowed to turn angularly in an opposite direction under the urging force of the spring means at a user controlled angular speed to releasably hold the rotor against further movement in said opposite direction with the blind in a selected extended condition, the latching member being caused to move into the pocket and out of contact with said cam surface under the influence of centrifugal force when the rotor is allowed to turn in said opposite direction under the urging force of the spring means at an uncontrolled angular speed.

A blind equipped with the above mechanism can be unrolled to a required extent by a user pulling on the free end of the blind. The blind is then allowed to retract very slightly under the urging force of the spring means but at a rate controlled by the user continuing to apply tension to the blind. In less than one revolution of the roller the latching device should operate to hold the blind in an extended condition. The blind may be fully retracted by firstly pulling on the extended blind to release the latching device and by then allowing the rotor to rotate freely under the urging force of the spring means so that the angular speed of the rotor will cause the latching member or members to move fully into respective pockets where they will be spaced from the cam surface of the stator.

Preferred and/or optional features of the invention are set forth in claims 2 to 10.

The invention will now be more particularly described by way of example with reference to the accompanying drawings, in which: Figure 1 is a longitudinal section taken through one embodiment of a roller blind mechanism according to the present invention, Figure 2 is transverse cross-section through the rotor and stator of the latching device in one mode of operation, Figure 3 is a view similar to Figure 2 but showing the latching device in a second mode of operation, Figure 4 is an exploded perspective view of the latching device of the roller blind mechanism, Figure 5 is a fragmentary perspective view of a part of the latching device, Figure 6 is an inner end view of the assembled latching device, Figure 7 is a perspective view of the roller blind housing, and Figures 8 and 9 show a support bracket for the roller blind mechanism.

Referring now to the drawings, the roller blind mechanism shown therein comprises an elongate C-section housing 10 having integral end plates 11 and 12, a tubular roller 13, a latching device 14 supporting one end of the roller 13 in end plate 11 and a holder 15 supporting the other end of the roller in end plate 12.

The latching device 14 comprises a two part stator 16, 17, a rotor 18, latching members 19, and a torsion spring 20.

The stator part 17 is in the form of a spindle 21 having juxtaposed cam and disc portions 22 and 23, respectively, intermediate its ends. The cam surface 24 of the cam portion 22 is generally S-shaped defining two detents 25. The disc portion 23 has a two blind holes 26 communicating respectively with two diametrically opposed axially extending slots 27, a circumferential groove 28 and in an end face thereof two shallow recesses 29, each having a shallow ramp-shaped base 30 leading to an axially extending wall 31.

The stator part 16 has a cylindrical bore 32 receiving the outer end of the part 17, a radially extending lug 33 having a slotted planar end face 34, and an annular ledge 35 provided with two teeth 36 which are complementary in shape to the recesses 29 in the end face of the disc portion 23 of the stator part 17.

The stator parts 16 and 17 are urged together, with teeth 36 located in respective recesses 29, by spring clips 37 located in blind holes 26 and slots 27 and having ends 38 bearing on the ledge 35, the clips 37 being held in position by a resilient split ring 46 provided in the groove 28.

The rotor 18 has a portion 39 defining a chamber 40 receiving the cam portion 22 of the stator, a portion 41 provided with a cylindrical bore 42 by which the rotor is rotatably mounted on the stator, an externally threaded end portion 43, and a plurality of angularly spaced axially extending tapered ribs 44, which are a press-fit in the roller 13, on the outer surface of portion 41.

The chamber 40 of the rotor 18 communicates with three equi-angularly spaced rotor pockets 45. A cylindrical latching member 19 is held captive with respect to each pocket 45 and the trailing edge of each pocket as considered in a clockwise direction of Figures 2 and 3 has an arcuate cutout 47 The rotor 18 is fixed against axial movement relative to the stator part 17 by a washer 48 held in place by a spring clip 49 passing through the spindle 21.

An elongate torsion spring 20 is mounted on the spindle 21 externally of the rotor 18. One end of the spring 20 is located in a slot 51 in the inner end of spindle 21. The other end of the spring 20 is threaded on end portion 43 of the rotor and hooked around a protrusion 52 on the end of the portion 41 of the rotor.

The slotted end face 34 of the lug 33 on the stator part 16 is fitted over a rectilinear lower edge of a hole 53 in end plate 11 of the housing 10 to support one end of the roller 13. The holder 15 comprises a plug 54 press-fitted in the other end of the roller 13 and a spindle 55 mounted in a hole 56 in the end plate 12 to support the other end of the roller 13 for rotation.

The two part stator 16, 17 is for adjustment purposes. A screwdriver slot 57 is provided at the outer end of the spindle 21. If the blind does not fully retract under the urging force of spring 20 the roller blind mechanism can be adjusted by turning the stator part 17 relative to the stator part 16 in a direction such that the teeth 36 ride out of respective recesses 29 with the two parts 16 and 17 of the stator moving apart against the urging force of the spring clips 37, until the blind attains a fully retracted position.If on the other hand the tension in the spring 20 is too great, with the blind in a fully retracted condition, the stator part 17 can be moved axially relative to the stator part 16 by pressing on a screwdriver in slot 57 until the teeth 36 are clear of respective recesses 29 and the stator part 17 can be turned relative to the stator part 16 in an opposite direction. This will wind a part of the blind off the roller 13. The latching device 14 can be released by giving the blind a slight tug and then releasing it. The blind will wind back onto the roller and in so doing will reduce the urging force of the spring 20.

With a blind (not shown) attached at one end to the roller 13 and wound thereon, the blind may be unwound to a required extent by a user pulling on the free end of the blind. The rotor 18 is rotated relative to the stator 16, 17 against the urging force of the spring in an anti-clockwise direction as considered in relation to Figures 2 and 3. The latching members 19 will move freely over the upper part of the cam surface 24 and will fall into respective pockets 45 as the latching members pass over the lower part of the cam surface 24.

When the blind has been unwound to a required extent, the blind is allowed to retract slightly under the urging force of the spring 20 but at a rate controlled by the user continuing to apply tension to the blind. The latching member 19 immediately adjacent to the upper detent 25 and anti-clockwise thereof will engage behind the detent as shown in Figure 2 to prevent further retraction of the roller. To fully retract the blind the user firstly pulls on the blind again to release the latching member 19 from the upper detent 25 by angularly displacing the rotor 18 anti-clockwise with respect to the stator 16, 17. The blind is then released by the user so that the rotor 18 is allowed to rotate freely under the urging force of the spring 20.The angular speed of the rotor will be such that all three latching members 19 are thrown radially ontwardly into their respective pockets 45, as shown in Figure 3, where they will be spaced from the cam surface 24.

The stator parts 16, 17 and the rotor 18 are preferably of plastics material, and the cylindrical latching members 19 are preferably metal. The cut-outs 47 are provided to minimise wear at these positions on the rotor surface caused by latching.

The cut-outs 47 are, however, not essential.

The housing 10 may be secured to a horizontal support surface, such as is commonly provided above a window, using the support brackets 58 having clip portions 59 shown in Figures 8 and 9. Two brackets 58 are secured to the horizontal surface at appropriately spaced positions by screw fasteners which pass through holes 60 in lugs 61. The housing 10 is then mounted onto the support brackets 58 by sliding the upper wall of the housing 10 over the clip portions 59 until shaped ends 62 of respective clip portions 59 pass beyond a step 63 in the housing upper wall.

The above embodiment is given by way of example only and various modifications will be apparent to persons skilled in the art without departing from the scope of the invention defined by the appended claims. For example, the rotor need only have one latching member and the cam surface of the stator need only have one detent provided that it is arranged in use in the upper region of the stator.

Claims

1. A roller blind mechanism comprising a roller, means for supporting the roller for rotation between a blind retracted condition and a blind extended condition, spring means urging the roller towards a blind retracted condition and a latching device for latching the roller in a selected blind extended condition, said latching device comprising an outer rotor mounted for rotation with the roller, an inner stator within: the rotor, the stator being fixed relative to said supporting means, and at least one latching member between the stator and the rotor, the latching member being held captive with respect to a pocket in the rotor and the stator having a cam surface shaped so that the locking member will pass over the cam surface and move inwards and outwards of said pocket as the rotor is turned in an angular direction to extend the blind and so that the latching member will engage the cam surface when the rotor is allowed to turn angularly in an opposite direction under the urging force of the spring means at a user controlled angular speed to releasably hold the rotor against further movement in said opposite direction with the blind in a selected extended condition, the latching member being caused to move into the pocket and out of contact with said cam surface under the influence of centrifugal force when the rotor is allowed to turn in said opposite direction under the urging force of the spring means at an uncontrolled angular speed.

2. The roller blind mechanism of claim 1, wherein the cam surface of the stator has at least two detents, spaced angularly with respect to each other, one or other of the detents being engageable by the latching member depending on the angular orientation of the stator in use.

3. The roller blind mechanism of claim 1 or claim 2, wherein the rotor has a plurality of said pockets and a corresponding number of associated latching members.

4. The roller blind mechanism of claim 1, 2 or 3, wherein the latching member or members are of cylindrical shape.

5. The roller blind mechanism of anyone of the preceding claims, wherein the spring means comprises an elongate torsion spring.

6. The roller blind mechanism of anyone of the preceding claims, wherein the stator has an axial splindle-shaped extension and the rotor has an axial extension provided with a cylindrical bore by which the rotor is mounted on the extension of the stator for rotation relative thereto.

7. The roller blind mechanism of claim 6, when dependent on claim 5, wherein the torsion spring is mounted about an end portion of the spindle-shaped extension of the stator and is connected at one end to the free end of the spindle-shaped extension and at its other end to the rotor.

8. The roller blind mechanism of anyone of the preceding claims, wherein the roller is tubular and the rotor is press-fitted in an end of the roller.

9. The roller blind mechanism of anyone of the preceding claims, wherein the stator comprises two parts which are angularly displaceable relative to one another.

10. The roller blind mechanism of anyone of the preceding claims, wherein the supporting means comprises an elongate C-section housing provided with end plates, the roller being supported at one end by the stator which is fixed to one end plate and at the other end by the other end plate.

11. A roller blind mechanism substantially as hereinbefore described with reference to the accompanying drawings.