GB2113749A - Roller shutter - Google Patents

Abstract

A roller shutter assembly comprises a shutter consisting of elongate laths 11 hinged together along their longitudinal edges by elongate flexible hinge strips 12 of resilient material in the form of shallow channels and a loading means, e.g. a spring-loaded roller, to hold the shutter in tension during both raising and lowering. The edge portions 13 of the hinge strips 12 are retained in undercut grooves 14 at each edge of the laths 11. Mounting means for guide rollers may be provided. <IMAGE>

Description

SPECIFICATION Shutters This invention relates to shutters which comprise an assembly of at least three laths hinged together along their longitudinal edges and resilient loading means which act upon the shutter in a direction substantially normal to the longitudinal edges of its laths whereby to urge the shutter towards a storage location so that during opening and closing movement of the shutter, each hinge is subjected to a tensile load which tends to separate the two laths it hinges together.

British Patent Specifications Nos. 937,771; 1,013,644; 1,278,496 and 1,486,550 disclose various forms of hinges by which adjacent laths of a shutter are hinged together along their longitudinal edges. In each case a typical lath is formed with a projection along one of its longitudinal edges and a complementary recess along its other longitudinal edge, the hinge by which an adjacent pair of the laths are connected together being formed by the interengagement of the projection of one of the laths within the complementary recess of the other lath. Such hinged joints are vulnerable to grit, liable to wear due to friction between the interengaged parts, are prone to jamming, are noisy in operation and may require an extra seal at each hinged joint.

An object of this invention is to provide an alternative form of hinge arrangement for a shutter which does not suffer from the foregoing disadvantages to the same extent.

U.K. Patent Specification No. 1 262,835 discloses a door hinge comprising a member of resilient material having two wings interconnected by a flexible web which constitutes the pivot portion of the hinge. Each wing is inserted in a slot formed by a channel section fastening strip which is fixed respectively to the door or the door frame, and is retained in that slot by rivets. Such a hinge is unsuitable for use as a hinge connecting adjacent laths of a shutter because the use of the necessary fastening means, such as rivets, is impractical and commercially unviable for various reasons such as lack of space and cost.

According to this invention there is provided a shutter comprising an assembly of at least three laths hinged together along their longitudinal edges and resilient loading means urging the assembly of laths to an open condition such that each hinge is subjected to a tensile load which tends to separate the two laths it hinges together, wherein each hinge comprises an elongate strip of resilient material having enlarged formations along its longitudinal edges, the enlarged formations of each strip being received and retained within longitudinally extending recesses which are formed by respective longitudinal edges of the laths that are hinged together by that strip, each recess having a longitudinally extending mouth through which the strip extends, the mouth being narrower than both the interior of the recess and the enlarged formation along the longitudinal edge of the strip that is located therein, the mass of the resilient material of that formation and the configuration of that formation being such that it cannot be squeezed through the mouth during normal usage of the shutter.

Preferably each strip has a shallow channel section, the enlarged formations comprising the side walls of the channel section and the base of the channel section being the part of the strip that extends through the mouths of the opposed recesses. The outer surfaces of the side walls may taper away from the base of the strip.

The inner face of each side wall may be recessed, preferably adjacent the base, in the natural unloaded state of the resilient material. The recess may be a tapered recess formed between the base and a face which makes an acute angle with the base.

Roller shutters in which this invention is embodied will be described now by way of example with reference to the accompanying drawings, of which:~ Figure 1 is a fragmentary view in perspective of a simple form of roller shutter in which this invention is embodied; Figure 2 is a cross-section of a typical intermediate lath of a preferred form of roller shutter in which this invention is embodied; Figure 3 is a cross-section of the bottom lath of the preferred form of roller shutter which includes intermediate laths as shown in Figure 2; Figure 4 is a cross-section of a typical flexible hinge strip of the preferred form of roller shutter which comprises the lath shown in Figures 2 and 3;; Figure 5 is a sectioned fragment of the preferred form of roller shutter showing one longitudinal edge of a strip as shown in Figure 4 inserted in the respective longitudinal recess of a lath as shown in Figure 2 or Figure 3 when the hinge is unladen; and Figure 6 is a view similar to Figure 5 showing the condition of the strip when the hinge is loaded such as can occur during closing movement of the shutter and when the shutter is latched closed.

A vehicle, such as a fire engine, has an opening which provides access to a storage compartment.

The opening is normally closed by a roller shutter 10.

Figure 1 shows that the roller shutter 10 comprises a plurality of elongate laths 11 which are hinged together along their longitudinal edges by elongate flexible hinge strips 12 of resilient material. The longitudinal edges of each strip 12 are enlarged and the enlarged formations 13 are received and retained within longitudinally extending recesses 14 which are formed by the longitudinal edges of the laths 11.

The lath (not shown) at one end of the shutter 10 is fixed to a storage roller which is mounted within the compartment adjacent to and substantially parallel to the upper edge of the opening. The storage roller is spring loaded in the direction in which it must rotate to draw the shutter 10 across the opening so as to open the opening, the shutter 10 being wrapped around the roller as it is so drawn.

A handle (not shown) is provided on the outer surface of the shutter 10 so that an operator can restrain opening movement of the shutter 10 so that it does not open too quickly under the action of the spring loading of the roller and can move the shutter 10 against that spring loading to close it. There is also a latch mechanism (not shown) by which the shutter 10 is latched closed. The handle and latch mechanism may be as described and claimed in our co-pending British Patent Application No. 8236061 which designates priority of British Patent Application No.

8200377.

Figures 2 and 3 show the cross-sections of metal extrusions from which the preferred forms of lath are cut. Figure 2 shows a typical lath which has longitudinal recesses 14 formed by both its upper and lower longitudinal edges whilst Figure 3 shows the bottom lath which only has such a longitudinal recess 14 formed by its upper longitudinal edge.Each longitudinal recess 14 is bounded by the longitudinally-extending peripheral portion 15 of the main flat part of the extension that forms the front, outwardly-facing surface of the lath, by a short wall portion 1 6 which is aligned with, is normal to and is spaced from the outer edge of the peripheral portion 1 5 to form a mouth 17. by a short wall 18 which is parallel to the peripheral portion 15 and which extends inwards from the end of the short wall 16 that is remote from the mouth 17, and by an angled wall 19 which joins the inner end of the short wall 18 to the main flat part of the extension.

The angle that is included between the angled wall 19 and the peripheral portion 15 is an acute angle.

A body 21, which is integral with the short wall 18 of the longitudinally-extending recess 14 that is formed by the upper longitudinal edge of each lath (including the bottom lath), has a longitudinally-extending bore 22 formed in it. A longitudinally-extending slot 23 is formed in the wall of the bore 22 remote from the recess 14. A similar body 24 forming a longitudinally-extending bore 25 is supported from the lower edge of the bottom lath. A longitudinally-extending slot 26 is formed in the wall of the bore 25 that faces the body 21. The bores 22 and 25 receive stub axles of guide rollers which are supported adjacent the ends of the laths, for engagement with guideways formed along the vertical edges of the opening.

Figure 4 shows the cross-section of an extrusion of resilient material from which the preferred forms of hinge strip 12 are cut. It is a shallow channel section. The outer faces of the side walls 27 and 28 taper away from the base 29. The inner faces of the side walls 27 and 28 are recessed adjacent the base 29. Each recess is tapered being formed between the base 29 and an angled face 31, 32 which extends from the base 29 to a location in the inner face of the respective side wall 27, 28 which is approximately mid-way between the base 29 and the remote end of the respective side wall 27, 28.

Figure 5 shows that the enlarged formation 13 formed by each side wall 27,28 of the hinge strip 12 fits snugly into the recess 14 of the respective lath 11 when in its natural unloaded condition, the depth of the base 29 being substantially equal to the width of the mouth 1 7, the height of the side wall 27, 28 being substantially equal to the corresponding dimension of the recess 14 and the angle of taper of the outer surface of the side wall 27, 28 being substantially equal to the acute angle included between the angled wall 19 and the peripheral portion 1 5. A space is formed between the inner face of the side wall 27,28 and the short wall 16 by the tapered recess in the former.

The hinge strips 12 are subjected to lateral tensile loads which tend to separate the enlarged formations 13 formed by the side walls 27 and 28 when the shutter 10 is being pulled down to its closed position against the spring loading, whilst it is latched in the closed condition, and usually even during the opening movement. The side walls 27 and 28 retained within the respective recess 14 are deformed by these tensile loads and this deformed condition is illustrated in Figure 6.This deformation leads to a disappearance of the recess in the inner wall of the side wall 27, 28 and to that part of the side wall 27. 28 that extends from the base 29 to its end that is remote from the base 29 being compressed so that the force required to pull the side wall 27, 28 from within the recess 14 through the mouth 17 is greater than would be required if pressure of the material of the strip 12 was substantially uniform throughout.

Other configurations of hinge strip and longitudinal recesses in the laths may be used. For example, the recess that is formed by the inner face of each side wall of the hinge strip 12 may be omitted. The ratio of the cross-sectional area of the enlarged formation that extends along each longitudinal edge of the elongate strip of resilient material of a hinge of a shutter in which this invention is embodied to the width of the mouth of the longitudinally extending recess within which that formation is retained is a critical factor but that is dependent upon so many variable physical characteristics, such as the elasticity of the resilient material, the shape of the enlarged formations and friction, for example, that it can only be determined empirically for each hinge design.

Claims (7)

1. A shutter comprising an assembly of at least three laths hinged together along their longitudinal edges and resilient loading means urging the assembly of laths to an open condition such that each hinge is subjected to a tensile load which tends to separate the two laths it hinges together, wherein each hinge comprises an elongate strip of resilient material having enlarged formations along its longitudinal edges, the enlarged formations of each strip being received and retained within longitudinally extending recesses which are formed by respective longitudinal edges of the laths that are hinged together by that strip, each recess having a longitudinally extending mouth through which the strip extends, the mouth being narrower than both the interior of the recess and the enlarged formation along the longitudinal edge of the strip that is located therein, the mass of the resilient material of that formation and the configuration of that formation being such that it cannot be squeezed through the mouth during normal usage of the shutter.

2. A shutter according to Claim 1, wherein each strip has a shallow channel section, the enlarged formations comprising the side walls of the channel section and the base of the channel section being the part of the strip that extends through the mouths of the opposed recesses.

3. A shutter according to Claim 2, wherein the outer surfaces of the side walls of each strip taper away from the base of that strip.

4. A shutter according to Claim 2 or Claim 3, wherein the inner face of each side wall is recessed in the natural unloaded state of the resilient material.

5. A shutter according to Claim 4, wherein the recess formed in the inner face of each side wall in the natural unloaded state of the resilient material is adjacent the base of the respective strip.

6. A shutter according to Claim 4 or Claim 5, wherein the recess formed in the inner face of each side wall in the natural unloaded state of the resilient material is a tapered recess formed between the base of the respective strip and a face which makes an acute angle with that base.

7. A roller shutter substantially as described hereinbefore with reference to the accompanying drawings.