GB2242469A

GB2242469A - Preventing unwinding of roller curtain or blind

Info

Publication number: GB2242469A
Application number: GB9101846A
Authority: GB
Inventors: Gordon Bradbury
Original assignee: James and Bloom Ltd
Current assignee: James and Bloom Ltd
Priority date: 1990-03-07
Filing date: 1991-01-30
Publication date: 1991-10-02
Anticipated expiration: 2011-01-30
Also published as: GB2242469B; GB9101846D0; GB9005095D0

Abstract

The invention is a roller curtain comprising means for limiting the extent to which the curtain can be unwound from the sprung-roller, comprising a flexible element e.g., a strap 10, having respective ends connected to the curtain 5 at different longitudinal position and being disposed to embrace the sprung-roller 1 whereby on unwinding the curtain from the roller the flexible element becomes tensioned about the roller to prevent further unwinding of the curtain. <IMAGE>

Description

TITLE: ROLLER CURTAIN DESCRIPTION The invention relates to flexible roller curtains more particularly, but not exclusively, of the kind used on commercial vehicles to secure or protect the cargo.

It is normal for flexible roller curtains used on commercial vehicles to comprise a curtain made for example of textiles such as canvas impregnated with polyvinylchloride or the like, the curtain being wound onto a spring-urged roller or barrel for storage.

Therefore the curtain is constantly urged into a retracted position in which it is wound around the spring -urged roller and in use is unwound from the roller to the required extent e.g. in the manner of a roller blind.

It has been found that when commercial vehicles incorporating such roller curtains are travelling at high speed there is a tendency for the curtains to be sucked in or out as a result of air pressure differences and that it is not possible to retain the curtain in a flat condition due to the inherent flexibility of the curtain and due to the fact that the curtain is free to move vertically because of the sprung roller. It is known to stiffen such curtains horizontally with a series of transverse rods or other stiffening members and it is also known to mount the ends of the rods in guides again to stiffen the curtain. Such attempts have however not always been successful and in extreme cases it is still possible for the ends of the rods to become detached from their guides.

Therefore, from one aspect the invention is a modified arrangement wherein the ends of the stiffening rods are provided with rollers, shoes or other guide members which are located in guide tracks in the form of necked channels so that they positively embrace the rollers to prevent lateral removal of the rollers from the guide channels.

There remains the problem that the curtain can still move vertically due to its flexibility and due to the fact that the sprung roller is able to rotate in either direction.

To prevent unintended over-rotation of the sprung roller we now propose means for locking the sprung roller against over-rotation.

From another aspect the invention is thus a roller curtain comprising means for limiting the extent to which the curtain can be unwound from the sprung roller comprising a flexible element, e.g. a strap, having respective ends connected to the curtain at different longitudinal positions and being disposed to embrace the sprung roller. The flexible element preferably comprises a pair of straps connected between the inner end of the curtain and an intermediate position adjacent to the inner end of the curtain. Suitably the ends of the straps may be connected to lateral stiffening rods in the curtain. Preferably the strap is connected between two adjacent lateral stiffening rods. The straps may be adjustable in length by means of buckles or the like whereby the effective length of the curtain can be adjusted.

Thereby the invention provides an arrangement in which on unwinding the curtain from the roller the flexible element becomes tensioned about the roller to prevent further unwinding of the curtain.

The invention is diagrammatically illustrated by way of example in the accompanying drawings, in which: Figure 1 is an exploded perspective view of a roller curtain; Figure 2 is a cross-sectional view taken on the line A-A of Figure 1; Figure 3 is a cross-sectional view taken on the line B-B of Figure 1; Figure 4 is a cross-sectional view of a detail of Figure 1; Figure 5 is a view similar to that of Figure 2 and showing a restraining strap, and Figure 6 is a view similar to that of Figure 5 but in a different position of operation.

In the drawings a roller curtain intended for a commercial vehicle to provide restraint or protection for the vehicle cargo comprises a spring-urged roller barrel 1 rotatably mounted on a pair of supports 2, only one of which can be seen in the drawing, the supports 2 being secured to the vehicle body by means of brackets 3. An oppositely disposed pair of guide channels 4 are secured to the vehicle body below the brackets 3 for the purpose appearing hereafter.

Wound around the spring tensioned roller barrel 1 is a curtain 5 of polyvinylchloride or the like which is stiffened by a series of laterally extending rods 6 disposed in pockets 14 in the curtain, the ends of the rods 6 being provided with guides in the form of rollers 7 which are disposed in the guide channels 4. The bottom of the curtain 5 carries a bottom rail 15 to provide rigidity and a finger rail 8 to facilitate manipulation of the curtain. As can be seen more clearly in Figure 4 of the drawings the guide channel 4 is necked or reduced in width at its entrance slot 9 to prevent lateral displacement of the rollers 7. If desired the guide channel member could be extruded from aluminium or the like, in which case the necking could be formed by projections extending into the guide channel proper.

These projections could, if desired, be spaced away from the entrance slot.

A pair of restraining straps 10, only one of which can be seen in the drawings, are secured to the curtain to limit the amount by which the curtain can be unrolled from the roller barrel 1, each strap 10 being secured at one end 11 to the barrel and to the end of the curtain 5 e.g. by means of fixing 16, see Figure 2, and by its other end 12 to an intermediate portion of the curtain remote from its end 11. Preferably the restraining straps are secured around a stiffening rod 6 disposed at the end of the curtain and around the next adjacent stiffening rod 6. The tensioning straps are arranged to extend round the side of the spring barrel 1 opposite to that from which the curtain is unwound so that eventually, as shown in Figure 5 of the drawings, the straps become tensioned to prevent further rotation of the spring barrel 1. The length of each strap 10 can be adjusted by means of a buckle 13 so that the extent to which the curtain can be unrolled can be set, e.g. at the time of installation.

As shown in Figure 6 of the drawings the straps fold up into the curtain when it is rolled onto the spring barrel 1.

The invention thus provides simple and effective means for locking the roller against over-rotation so that the curtains can be fully tensioned in use.

Claims

1. A roller curtain having a spring-urged roller, a curtain secured to the roller and means for limiting the extent to which the curtain can be unwound from the sprung roller comprising a flexible element having repsective ends connected to the curtain at different positions along the curtain and being disposed to embrace the sprung roller whereby on unwinding the curtain from the roller the flexible element becomes tensioned about the roller to prevent further unwinding of the curtain.

2. A roller curtain according to claim 1, wherein the flexible element comprises a pair of straps connected between the inner end of the curtain and an intermediate position adjacent to the inner end of the curtain.

3. A roller curtain according to claim 2, wherein the ends of the straps are connected to lateral stiffening rods in the curtain.

4. A roller curtain according to claim 3, wherein each strap is connected between two adjacent lateral stiffening rods.

5. A roller curtain according to claim 3 or claim 4, wherein the ends of the stiffening rods are provided with guide members located in guide tracks in the form of necked channels so that the tracks positively embrace the guide members to prevent lateral displacement of the guide members from the guide channels.

6. A roller curtain according to any preceding claims, wherein each flexible element is adjustable in length whereby the effective length of the curtain can be adjusted.

7. A roller curtain substantially as hereinbefore described with reference to, and as illustrated in, the accompanying drawings.