GB2386049A - A free standing copper gastropod barrier - Google Patents

Abstract

A free standing defensive barrier against slugs and snails in the form of a short cylindrical tube which encircles the area and /or the plants to be protected. The tube 1 is formed from a rectangular sheet of copper or copper coated material 7 by folding. Folds are made along the long edges 3 and the cylinder is completed by tucking a flap 4 formed from one short side into the recess 5 formed by the folds on the other short end. The flap is held in the recess by friction. In use the tube is easily opened to fit around individual plants or groups of plants and then closed to form a complete barrier.

Description

<Desc/Clms Page number 1>

PEST CONTROLLER This invention concerns a pest controller in the form of a physical barrier to protect a space from invasion by gastropods. More particularly, it relates to free-standing enclosing but openable fences containing copper which slugs and snails are loath to crawl over.

Slugs and snails are some of gardeners'worst enemies as they are so voracious that they tend to overgraze young seedlings, thus killing the plants, and can cause serious damage to mature plants overnight. Slug and snail problems are not limited to plant damage, there are many places from which one might want to exclude them, for example from pets'food bowls, or from ornamental statues which can be disfigured by slime trails.

Most previous technology to deal with slugs and snails works on the principle of killing them, generally with poisons. Gastropods which have ingested poisons can, in turn, poison the wildlife that preys on them, thus reducing the numbers of predators which someone with a slug or snail problem would wish to encourage. Killing the prey also results in a reduction in the availability of prey which has a bad effect on these useful predators.

Defensive barriers which prevent slugs and snails from entering a space do not have the disadvantage of harming wildlife (which includes slugs and snails). Slugs and snails dislike crawling on copper, possibly because they dislike the taste (a snail or a slug has taste buds on it's foot and it's blood is copper based, unlike mammals whose haemoglobin in the bloodstream contains iron). A free-standing barrier of sufficient height that has copper on its surface will deter slugs and snails from climbing over it. Since, to be effective, a barrier must have no gaps, it must be in the form of a closed loop. However a problem arises when it is required to remove an encircling barrier from a plant which has grown too bushy and wide to slide the barrier up and off from above, or when the barrier surrounds something which prevents the barrier sliding off (for example when the barrier surrounds a table leg, a plant with a very tall stake, or a plant growing up from the ground and then twining through a trellis). So a completely encircling barrier is required, but it must be capable of being opened. For simplicity's sake a barrier would preferably only have one opening, thus it would have to be flexible enough to distort sufficiently to open up a gap in the ring. A barrier can be easily distorted if it is the form of thin sheet, which could be easily joined, for instance, with nuts and bolts. However the join must have no small separate parts since they would be too fiddly and could be easily lost in messy conditions (for instance in the soil of a flower bed or allotment). For the same reasons the join should not require any tools to open and close it. The join also needs to be easy to understand, as typical users will have no previous experience of a novel kind of join, and easy to use, as they may not have great dexterity. So one problem is to provide the sheet barrier with a join which will fulfil all the above requirements, and will do that in dirty, gritty outdoor conditions over a long period of time.

Defensive slug barriers have been used before. There is a tape which is in the form of stickybacked, paper-thin copper foil for sticking to hard surfaces like the rims of flower pots. This tape is removable (rendering it subsequently unusable, like sellotape, in the process) but as it not self-supporting, it is of no use for the protection of plants in a flower bed. Other available

<Desc/Clms Page number 2>

barriers, which are mostly made of plastic and are intended to work by the principles of convoluted pathways or spikes or poison in troughs to discourage crawling gastropods, cannot be opened to make a gap in the ring.

The purpose of this invention is to provide a pest controller in the form of a novel self supporting enclosing barrier which will fence off an area of a surface against the ingress of slugs and snails, while at the same time having an openable join so that the pest controller is easily removable even where there is an obstruction within the space which would prevent the barrier being removed by simply lifting it away from the surface. The join is of a novel kind which is intended to be simple to use and understand, which requires no separate parts or tools, and which will reliably hold closed, leaving no gaps, while being easy to open and close in the gritty conditions of a flower bed. The barrier is made from a sheet material with copper on its surface which slugs and snails are capable of crossing, but generally choose not to.

This invention consists of a low fence made from a copper sheet material, in the shape of a complete, but openable short tube which has a join parallel to the axis, and whose two circumferential edges are folded to form a socket on one side of the join, into which can be removably inserted a tongue formed from the body of the ring at the other side of the join.

This invention is a low fence. By'low'is meant at least the same height as the length of a typical slug, as the required size of the fence relates to the size of the gastropods being fenced off. By'fence'is meant a sheet barrier placed with one edge onto or into a surface, and tall enough to prevent anything moving close to the surface from passing over it. From tests I have found that the preferred minimum height to be used in Britain is 50 mm. Even in a situation where protection is required from very small gastropods a height lower than 50 mm is not advisable, as lower heights carry a risk of stray overhanging vegetation providing bridges, or soil clods forming ramps, which would assist gastropods to cross the barrier The sheet material is made from copper, because slugs dislike crawling on copper. The copper is preferably > 99% pure to minimise corrosion when used in an outdoor environment, but copper of lesser purity can also be used. Whether the surface is corroded or new does not affect the efficiency of the pest controller: tests have shown that copper with a thick layer of green verdigris is just as effective as bright copper. Any sheet material which has sufficient copper on its surface, e. g. stiff plastic sheet with copper particles partially embedded in its surface, can also be used. I have discovered that half-hard (VPN 80) copper ( > 99% pure) sheet 0.45 mm thick provides the ideal compromise between flexibility (to allow for distortion without permanent damage when opening), and stiffness (for maintaining a consistent fit between the tongue and the socket).

The pest controller is made from a sheet material which is preferably in the form of intact sheet, but the barrier can also be made from close mesh (e. g. woven wire) or perforated sheet, provided that the openings are not so large as to allow a gastropod to pass through without being forced into enough contact with the copper to deter it from entry. The material must be flexible enough (by its nature and its thickness) that the gap in the join can be comfortably hand-opened by distorting the body of the ring. The tubes can be manufactured from readily available very long narrow sheets of copper in the form of coils.

<Desc/Clms Page number 3>

The shape of the barrier is that of a short circular tube. Circular is the preferred shape, as, in comparison to any other shape, for example any shape with straight sides, it maximises the area protected for any given length of enclosing barrier. Circular is also the preferred shape because it maximises the shortest distance from anywhere on the rim to the thing protected in the centre, frustrating very large slugs from stretching across the barrier. However any other enclosing shape can be used; sometimes users choose to distort the circle to fit around an unsymmetrical plant. Preferably the join is on a curved part of the barrier as curved tongue and socket joins retain their effectiveness better than straight ones after hard use.

A join is formed as a slit dividing the tube at one place parallel to its axis, so that the gap at the join can be bent open far enough for an obstruction to pass through by distorting the thin sheet from which the pest controller is made. The full-width tongue and socket design ensures that there are no appreciable gaps when it is closed.

The two circumferential edges are folded over to soften the sharp edges of the thin sheet, to provide stiffness at the edge (for scrunching into soil), and to form the socket on one side of the join. Any suitable fold of more than 90 degrees could create a socket to hold the tongue, but the preferred form is to fold the edge over through 180 degrees all the way back to the parent metal, which leaves no sharp edges, is easily reproduceable in manufacturing, and makes the most effective grip. This fold can be either both edges inwards or both edges outwards, inwards being preferred for aesthetic reasons.

The gap in the socket formed at one side of the join is dimensioned to be a tight fit on the tongue in order to reliably retain it by friction alone. As this is the simplest it is the preferred way, however the tongue or the socket or both can be made from material which has any non-smooth surface whose geometry provides sufficient mechanical grip.

Close to the join the folded edges are missing, producing a tongue from the body of the controller.

This tongue is cut slightly narrower than the overall width of the ring to provide widthways clearance in the socket. A 12 mm long tongue is the preferred length for typically a 100mm diameter ring of 0.45 mm thick copper sheet with a reasonably smooth mill-finished surface.

The ring is notionally manufactured by folding both edges of a straight strip which has had two comers notched at one end (the tongue end), then by rolling the resulting piece into a hoop shape.

<Desc/Clms Page number 4>

A possible embodiment of the invention, as an illustration, will now be described with reference to the accompanying drawings (Figs 1 to 6) in which: Figure 1 shows a ring, placed in this case on soil and enclosing a plant to protect it from snails Figure 2 shows a cross section through the ring, to illustrate the circumferentially folded edges Figure 3 shows one side of the join with the folded edges cut away to form a tongue Figure 4 shows the other side of the join, forming a socket Figure 5 shows a ring opened Figure 6 shows a ring closed The pest controller is formed as a short tube (1) of 0.45 mm thick half-hard (VPN 80) copper sheet, purity > 99%, 100 mm diameter, split in one place (2) parallel to the tube's axis to make it capable of being opened (7).

10 mm of both circumferential edges are folded inwards through 180 degrees to make a stiff'safe edge' (3) on the tube's rims to make an overall axial length of 50 mm.

The folded edges are omitted for the last 12 mm of ring at one side of the join, forming a tongue (4). The tongue is cut slightly narrower than the overall width of the ring to provide widthways clearance in the socket.

The folded edges at the other side of the join are opened up to approximately the thickness of the sheet material, forming a socket (5). The widths of the gaps (6) in the socket are adjusted tight enough to allow the tongue to be gripped by the socket, holding the ring closed, yet loose enough to allow the join to be easily pulled apart by hand.

The ring surfaces are left unprotected by any coating (e. g. lacquer) which might insulate slugs and snails from direct contact with the copper.

Claims (5)

1. CLAIMS: 1. A low fence made from a copper sheet material, in the shape of a complete, but openable tube which has a join parallel to the axis, and whose circumferential edges are folded to form a socket on one side of the join, into which can be removably inserted the tongue formed from the body of the tube at the other side of the join.
2. 2. A pest controller as claimed in claim 1 whose tongue is held in the socket at the join by friction alone or whose tongue or socket or both are made from material which has a non-smooth surface whose geometry provides the necessary mechanical grip.
3. 3. A ring as claimed in any of the preceding claims which is of any shape in plan view, not necessarily circular, that completely encloses an area of a surface when placed with the ring's axis approximately at right angles to that surface.
4. 4. A ring as claimed in any of the preceding claims which is made from copper metal.
5. 5. A gastropod barrier substantially as herein described and illustrated in the accompanying drawings