GB2254356A

GB2254356A - Cut-resistant roller shutter

Info

Publication number: GB2254356A
Application number: GB9206912A
Authority: GB
Inventors: Bernard John Burr
Original assignee: DIXONS GROUP PLC
Current assignee: DIXONS GROUP PLC
Priority date: 1991-04-05
Filing date: 1992-03-30
Publication date: 1992-10-07
Also published as: GB9206912D0

Abstract

A shutter curtain for security purposes has a number of elongate laths (10) each comprising the combination of a proformed metal strip (11) and an elongate cut-resisting body (12) secured to the strip (11). The cut-resisting body (12) is shaped to conform to the rear surface of the strip (11) and may be bonded to that surface or may be retained between the strip (11) and a metal rear cover (16) which may be welded to the strip (11) or formed integrally with it. The cut-resisting body comprises a polymer matrix (12B) and a plurality of hard particles (12C) of silicon carbide or like material. The longitudinal edges of each lath (10) are folded over to form hinged connections with neighbouring laths. <IMAGE>

Description

SECURITY APPARATUS This invention relates to a shutter curtain, and primarily to a shutter curtain for protecting business premises out of trading hours.

Xnown shutter curtains are available in a variety of forms, mostly comprising an assembly of elongate laths connected edge to edge by hinge joints. Such a curtain may be folded in concertina fashion or rolled up depending on the construction of the hinge joints and the method of mounting the curtain so that, when retracted, it takes the form of an elongate stack or roll. When closed, the laths generally form a planar screen, the free edge of which may be secured to maintain the screen in a closed and locked configuration.

Conventionally, the laths are formed from sheet steel or extruded aluminium. Such curtains have been successfully used in the past to prevent burglary, but they are proving inadequate for protecting against modern cutting apparatus such as motorised abrasive disc cutters.

According to this invention, a shutter curtain comprises a plurality of elongate laths connected to each other along their longitudinal edges so as to be hinged with respect to each other, wherein at least some of the laths each comprise the combination an elongate base member, and an elongate cut-resisting member parallel to and secured to the base member. Preferably the laths each comprise a metal strip and an elongate composite body secured to the strip, the body including a polymer matrix and a material which is harder than the metal of the metal strip. Typically the strip is preformed, for example, by stamping, by bending about a longitudinal axis, by moulding, or by extrusion to provide rigidity, with its longitudinal edges being folded over to form part of a hinged connection to neighbouring laths.The cut-resisting member preferably has a mating surface the profile of which matches the profile of one face of the metal strip. Thus, the metal strip may provide a curved concave face, with the mating surface of the composite body having a corresponding convex profile. The two parts may be bonded together, or simply held together by, for example, an elongate metal cover extruded with the base member as a single component forming an enclosure for the composite body.

Preferably, the outwardly facing surface of each lath is formed by the above-mentioned metal strip to deter attempts to detach the composite body.

In embodiments in which the composite body is bonded to the metal strip, it is preferred that the matrix material is a thermoset plastics such as epoxy or polyester resin. The matrix may be formed in contact with the strip itself, the strip acting as a mould, or it may be separately bonded to the strip using a bonding material which is of sufficient strength such that the composite body tends to fracture or bend before becoming detached from the metal strip. The particles suspended in the matrix are "hard" in the sense that they are harder than the material of the metal strip, and may be formed from crystals or granules of silica, silicate, other silicon materials, or other materials selected for hardness, e.g. silicon carbide, or crystalline aluminium oxide.It is also possible to reinforce the composite body with organic or inorganic fibres, preferably running lengthwise, for additional strength.

The invention also includes attaching composite members to the laths of existing shutter curtains to form laths having the combination referred to above.

The invention will now be described by way of example with reference to the drawings in which Figures 1, 2 and 3 are transverse cross-sections of portions of three alternative shutter curtains in accordance with the invention, and Figure 4 is a diagrammatic rear view of a shutter curtain lath.

A shutter curtain in accordance with the invention may comprise a plurality of elongate laths 10, three of which are shown in Figure 1, each lath 10 having a sheet metal base member in the form of a strip 11 having folded longitudinal edges which hook over the likewise folded edges of the neighbouring laths to allow a degree of pivotal movement sufficient to permit rolling of the shutter curtain around an axis parallel to the laths.

The strip 11 of each lath 10 is also bent about a longitudinal axis to present a convex surface 11A to the exterior and a corresponding concave surface liB to the rear. The strip has a constant cross-section substantially throughout its length.

Bonded to the concave surface liB is a composite rod 12 having a convex mating surface 12A of a radius matching the radius of the concave surface, the bonding material appearing as a thin layer 14 in Figure 1. The composite rod 12 has a solid matrix 12B of polymer material and a plurality of granules or pieces 12C of hard silicon material which represent at least 50% of the volume of rod 12.

In an alternative embodiment, shown in Figure 2, a composite lath member 12 is bonded to the metal strip 11, the composite lath member having a substantially planar exposed surface 12D, and a faceted inner surface 12A, here comprising three planar surface portions which are so angled with respect to each other as approximately to match the curvature of the strip 11.

A third embodiment, shown in Figure 3, has an elongate metal cover 16, the strip 11 and cover 16 being formed together as an extruded aluminium component. Alternatively the cover 16 may be made from sheet steel and may be spot-welded or otherwise connected at its edges to the strip 11 to form a sleeve enclosing a composite strip 12 with or without associated bonding material.

In all three embodiments, the composite member 12 may be a single component of the same length as the metal strip 10, or it may be made up of a plurality of much shorter sections.

Similar shutter curtain laths may be constructed with hinges allowing up to or beyond 1800 of pivoting for concertina folding.

The shutter curtain of the invention has a number of uses, the primary one being for closing the entrances to business premises out of trading hours. It may, however, also be of use for closing the opening of the load space of a goods vehicle or for closing off part of a shop, for example. It is primarily applicable the shutters which are substantially continuous in the sense that apertures are not provided.

Claims

1. A shutter curtain comprising a plurality of elongate laths connected to each other along their longitudinal edges so as to be hinged with respect to each other, wherein at least some of the laths each comprise the combination of a elongate base member and an elongate cut-resisting member parallel to and secured to the base member.

2. A shutter curtain according to claim 1, wherein at least some of the laths each comprise a metal strip and an elongate composite body secured to the strip, the composite body including a polymer matrix and a material which is harder than the metal of the metal strip.

3. A shutter curtain according to claim 2, wherein the metal strip has a preformed non-planar cross-section and has longitudinal edge portions folded over to form part of a hinged connection to neighbouring laths.

4. A shutter curtain according to claim 2 or claim 3 wherein the metal strip is preformed for rigidity, and wherein the strip and the composite body have adjacent surfaces with substantially matching profiles.

5. A shutter curtain according to claim 4, wherein the strip has a concave surface and the composite body has a convex surface.

6. A shutter curtain according to any of claims 2 to 5, wherein the composite body is bonded to a surface of the metal strip.

7. A shutter curtain according to any of claims 2 to 5, wherein the composite body is- located between the metal strip and an elongate rear cover portion.

8. A shutter curtain according to any of claims 2 to 7, wherein the said harder material comprises particles of an inorganic non-metallic material.

9. A shutter curtain according to claim 8, wherein the non-metallic material is silicon carbide or aluminium oxide.

10. A shutter curtain having elongate laths constructed and arranged substantially as herein described and shown in the drawings.