GB2070115A

GB2070115A - Roller blind clutch mechanism

Info

Publication number: GB2070115A
Application number: GB8005136A
Authority: GB
Original assignee: TIDMARSH ESTATE Ltd
Current assignee: TIDMARSH ESTATE Ltd
Priority date: 1980-02-15
Filing date: 1980-02-15
Publication date: 1981-09-03
Also published as: GB2070115B

Abstract

A releasable clutch for a roller blind mounted on a roller end plate 10 with an axle 12 comprises a coil spring 24 wound closely round the axle. One end 26 of the spring is located in the axle bearing 14 while the other end 36 is located in a collar 40 rotatably mounted with respect to the bearing. The friction between the spring and the axle allows rotation of the axle only in the sense (arrow 30) which tends to expand and so loosen the spring, however, when the collar is rotated e.g. by a cord attached to the lug 44, the spring is expanded, thereby allowing rotation of the axle in either direction. <IMAGE>

Description

SPECIFICATION Roller stop This invention relates to a releasable clutch suitable for a roller blind which can generally be described as a roller stop.

A roller blind is known in which the roller mechanism includes a helical spring which can be progressively coiled as the blind is pulled down to store energy for returning the blind when it is no longer held down. Such a roller blind mechanism requires a form of stop or clutch enabling the blind to be pulled down and to be retained pulled down but capable of release to enable the blind to be returned, and it is an object of the present invention to provide a releasable clutch suitable for a roller blind which enables the blind to be retained pulled down or partly pulled down, in any position but to be easily returned to the rolled up position.

According to the present invention a releasable clutch suitable for a roller blind comprises an axle, a coil spring closely wound on the axle with one end engaged in a fixed part, e.g. an axle bearing, and means for moving the other end angularly in relation to the axle.

The clutch can be made and sold as a subassembly for attachment to the end of a roller, or can be built integrally with a roller.

The said other end of the spring would normally be urged by the spring action so that the spring is a close fit on the axle, and in that condition the axle will be able to turn in its bearing in the one sense tending to unwind the spring but will be held against turning in the other sense which would tend to tighten the spring, and sufficient friction can exist between the axle and the spring to prevent that return movement. That condition is ideal for pulling a blind down since as soon as the pull is released, the clutch spring will engage the clutch to prevent the blind going back up again.

When the other end of the spring is moved to tend to unwind the spring, there is then little restraint against rotation of the axle in its bearing in either sense, so that the blind can be pulled up again by the helical spring in its roller.

in one simple form of the clutch the said other end of the spring extends radially through a slot in the bearing housing for engagement with a collar which can be rotated about an external cylindrical surface of the bearing housing by a cord hanging down at one side of the blind for releasing the clutch when the blind is to be raised.

The invention includes the clutch mechanism both as a pre-assembly and as a kit of parts, and also when assembled with a roller blind.

The invention may be carried into practice in various ways and one embodiment will now be briefly described by way of example with reference to the accompanying drawings in which: FIGURE 1 is an expanded isometric view of the clutch mechanism; and FIGURE 2 is a sectional elevation of the mechanism of FIGURE 1.

The roller clutch mechanism includes an end plate 10 which is secured to one end of the roller (not shown) for a roller blind.

The plate 10 has an integral axle 12 which is rotatably supported by a plain cylindrical bearing 14 extending through a housing 16. A sectional outer end 1 8 of the housing 1 6 fits in a square hold 20 formed in a fixed mounting bracket 22 to prevent the housing rotating.

A close-coiled spring 24 closely surrounds the axle 12 and has one end 26 bent to extend axially into a hole 28 formed in the housing 16 to be circumferentially located. The action of the spring is such that when the plate 10 is rotated in the direction of arrow 30, the slight friction between the coils of the spring 24 and the axle 12 tends to expand the spring and the roller is allowed to rotate. Should it be attempted to rotate the plate 10 in the opposite direction, indicated by the arrow 32, the friction between the spring 24 and the axle 12 tends to contract the coils of the spring and thus the coils bind against the axle to prevent it from rotating.

A hollow cylindrical portion 34 of the housing 16 surrounds the coil of the spring 24, and a radial extension 36 of the spring protrudes from the housing 16, passing through an arcuate cut-away portion 38 and into a hole 46 in an annular clip 40 which can turn around the outer cylindrical surface of the portion 34.

If it is desired to rotate the blind in the direction of the arrow 32, it is necessary to remove the frictional force exerted by the coils of the spring.

This is achieved by rotating the clip 40 in the direction of the arrow 32 which expands the coils of the spring to allow the axle to rotate in the bearing 14 freely in either direction. The clip 40 is conveniently operated by a cord attached to an external lug 44.

The blind is on a cylinder having an integral helical spring which winds up as the blind is pulled down and the cylinder is rotated. The action of the clutch described above normally allows the blind to be pulled down freely but stops the helical spring in the cylinder from pulling it back again, whatever position it is left in.

Then the cord attached at 44 can be pulled to release the clutch and allows the spring in the cylinder to return the blind.

The cord can be released when the blind is nearly back to enable the spring to re-coil and act as a brake.

1. A releasable clutch for a roller blind comprising an axle, a coil spring closely wound on the axle, the spring having one end engaged in a fixed part and its other end capable of angular movement about the axis of the axle, and means for moving angularly the said other end of the spring.

2. A clutch as claimed in Claim 1 in which the fixed part is a bearing for the axle.

3. A clutch as claimed in Claim 1 or Claim 2 in which the said other end of the spring is located in

**WARNING** end of DESC field may overlap start of CLMS **.

Claims

**WARNING** start of CLMS field may overlap end of DESC **. SPECIFICATION Roller stop This invention relates to a releasable clutch suitable for a roller blind which can generally be described as a roller stop. A roller blind is known in which the roller mechanism includes a helical spring which can be progressively coiled as the blind is pulled down to store energy for returning the blind when it is no longer held down. Such a roller blind mechanism requires a form of stop or clutch enabling the blind to be pulled down and to be retained pulled down but capable of release to enable the blind to be returned, and it is an object of the present invention to provide a releasable clutch suitable for a roller blind which enables the blind to be retained pulled down or partly pulled down, in any position but to be easily returned to the rolled up position. According to the present invention a releasable clutch suitable for a roller blind comprises an axle, a coil spring closely wound on the axle with one end engaged in a fixed part, e.g. an axle bearing, and means for moving the other end angularly in relation to the axle. The clutch can be made and sold as a subassembly for attachment to the end of a roller, or can be built integrally with a roller. The said other end of the spring would normally be urged by the spring action so that the spring is a close fit on the axle, and in that condition the axle will be able to turn in its bearing in the one sense tending to unwind the spring but will be held against turning in the other sense which would tend to tighten the spring, and sufficient friction can exist between the axle and the spring to prevent that return movement. That condition is ideal for pulling a blind down since as soon as the pull is released, the clutch spring will engage the clutch to prevent the blind going back up again. When the other end of the spring is moved to tend to unwind the spring, there is then little restraint against rotation of the axle in its bearing in either sense, so that the blind can be pulled up again by the helical spring in its roller. in one simple form of the clutch the said other end of the spring extends radially through a slot in the bearing housing for engagement with a collar which can be rotated about an external cylindrical surface of the bearing housing by a cord hanging down at one side of the blind for releasing the clutch when the blind is to be raised. The invention includes the clutch mechanism both as a pre-assembly and as a kit of parts, and also when assembled with a roller blind. The invention may be carried into practice in various ways and one embodiment will now be briefly described by way of example with reference to the accompanying drawings in which: FIGURE 1 is an expanded isometric view of the clutch mechanism; and FIGURE 2 is a sectional elevation of the mechanism of FIGURE 1. The roller clutch mechanism includes an end plate 10 which is secured to one end of the roller (not shown) for a roller blind. The plate 10 has an integral axle 12 which is rotatably supported by a plain cylindrical bearing 14 extending through a housing 16. A sectional outer end 1 8 of the housing 1 6 fits in a square hold 20 formed in a fixed mounting bracket 22 to prevent the housing rotating. A close-coiled spring 24 closely surrounds the axle 12 and has one end 26 bent to extend axially into a hole 28 formed in the housing 16 to be circumferentially located. The action of the spring is such that when the plate 10 is rotated in the direction of arrow 30, the slight friction between the coils of the spring 24 and the axle 12 tends to expand the spring and the roller is allowed to rotate. Should it be attempted to rotate the plate 10 in the opposite direction, indicated by the arrow 32, the friction between the spring 24 and the axle 12 tends to contract the coils of the spring and thus the coils bind against the axle to prevent it from rotating. A hollow cylindrical portion 34 of the housing 16 surrounds the coil of the spring 24, and a radial extension 36 of the spring protrudes from the housing 16, passing through an arcuate cut-away portion 38 and into a hole 46 in an annular clip 40 which can turn around the outer cylindrical surface of the portion 34. If it is desired to rotate the blind in the direction of the arrow 32, it is necessary to remove the frictional force exerted by the coils of the spring. This is achieved by rotating the clip 40 in the direction of the arrow 32 which expands the coils of the spring to allow the axle to rotate in the bearing 14 freely in either direction. The clip 40 is conveniently operated by a cord attached to an external lug 44. The blind is on a cylinder having an integral helical spring which winds up as the blind is pulled down and the cylinder is rotated. The action of the clutch described above normally allows the blind to be pulled down freely but stops the helical spring in the cylinder from pulling it back again, whatever position it is left in. Then the cord attached at 44 can be pulled to release the clutch and allows the spring in the cylinder to return the blind. The cord can be released when the blind is nearly back to enable the spring to re-coil and act as a brake. CLAIMS

3. A clutch as claimed in Claim 1 or Claim 2 in which the said other end of the spring is located in a collar which is rotatable with respect to the fixed part.

4. A clutch as claimed in Claim 3 in which the means for angularly moving the said other end of the spring comprises a cord attached to the collar.

5. A releasable clutch assembly for a roller blind constructed and arranged substantially as herein specifically described with reference to and as shown in the accompanying drawings.

6. A roller blind assembly including a releasable clutch as claimed in any of claims 1 to 5, the roller being connected to the axle of the clutch.