GB2124465A - Animal traps - Google Patents

Abstract

A trap has an entrance tunnel portion 1 leading to a nest-box portion 2, both of triangular cross-section. An entrance opening 3 is closable by a triangular door flap 4. A sheet of black rubber 5 or 6 providing thermal insulation is wrapped around each of the portions 1 and 2, each of which comprise three aluminium panels, to which the rubber sheet 5 or 6 is secured by an adhesive, with a floor panel joined to the two side panels by the rubber sheet which extends beyond one side panel partially to overlap the other side panel. The overlapping end 5a or 6a of each rubber sheet is detachably secured so that the trap may be collapsed for transport in a flat condition. The rubber sheet on the tunnel portion 1 hingedly connects the door flap 4 to the floor panel of that portion, the resilience of the rubber providing a spring force urging the flap to the closed position. A triggered trip mechanism, operated by the weight of an animal entering the trap, holds the flap 4 in the open position when the trap is set. <IMAGE>

Description

SPECIFICATION Animal traps This invention relates to animal traps and is particularly concerned with traps of the type commonly referred to as "live small mammal traps".

Such traps are used in large quantities by naturalists and zoologists, for example in ecological field studies when the animals caught are weighed, measured and tagged, etc., before being released. The small mammals, for example mice, voles and shrews, must be reliably caught and housed unharmed until studied and released, and a considerable number of traps must be set if the results obtained are to be of real scientific value.

The traps most commonly used are very bulky, with a body comprising a rectangular tunnel portion having an entrance closable by a top-hung hinged door flap and leading to a rectangular nestbox portion in which the trapped animals are housed. Field studies are often conducted in remote and inaccessible regions and the transport of, say, up to fifty traps to such a region presents considerable problems.

The main object of the invention is to provide a trap which in use possesses the advantages of the traps in use but overcomes the present transport problems.

According to the invention a trap has a body of triangular cross-section provided by a floor panel and two side wall panels, these three panels being hingedly interconnected at two pairs of contiguous edges and the other pair of contiguous edges being releasably interconnected to complete the triangular shape whereby release of these latter edges allows the body to be collapsed and transported in a substantially flat condition, the triangular entrance at one end of the body being closable by a triangular door flap hinged to the floor panel.

Preferably the body has an entrance tunnel portion and a larger section nest-box portion, each of these portions comprising three panels as described with the door flap hinged to the floor panel at the outer end of the tunnel portion and the opposite end of the nest-box portion being closed by a triangular end wall hinged to the floor panel of that portion. The panels may be of metal sheet, conveniently aluminium alloy sheet for lightness and resistance to corrosion, and they desirably have an outer layer of thermal insulation to protect the trapped animals from adverse external temperature conditions. This insulation may be provided by rubber sheet attached to the panels by a suitable adhesive, and this sheet may provide the hinged interconnection of the panels.

On each portion a single rubber sheet may extend around the three panels thereof, overlapping the releasably interconnected panel edges where the rubber sheet is provided with a "Velcro" or like readily releasable fastening.

A similar rubber hinge may be provided for the door flap, the natural resiliency of the rubber providing a door-closing spring force. A triggered trip mechanism, which holds the flap down in the open position when the trap is set, may include a treadle plate hinged to the floor panel of the tunnel portion and the movement of which under the weight of an animal stepping on it releases a trip wire to free the flap.

The invention will now be further described with reference to the accompanying drawings which illustrate, by way of example, a preferred embodiment of the invention. In the drawings: Figure 1 is a diagrammatic perspective view of the preferred trap embodiment; and Figure 2 is a plan view of the trap in collapsed condition, for packaging the transport.

The trap illustrated has a body comprising an entrance tunnel portion 1 of triangular crosssection leading to a nest-box portion of larger triangular cross-section. An inclined triangular entrance opening 3 at the outer end of the tunnel portion 1 is closable by a triangular door flap 4, shown in closed position in Figure 1. A sheet of black rubber 5 or 6 is wrapped around each of the body portions 1 and 2. This provides thermal insulation for protection of the trapped animals against adverse external temperatures and the black coloration increases the efficiency of the trap. It is an experimental fact that dark objects are investigated much more readily by small mammals than is the case with silver or other bright objects, so that a black trap in the open reduces animal avoidance.

Referring now to the collapsed condition shown in Figure 2, the tunnel portion 1 comprises a rectangular floor panel 7 and two identical side wall panels 8 and 9 which are also rectangular apart from being cut away at their outer ends to provide the inclined entrance 3. Thus the side panels 8 and 9 are actually trapezoidal as shown.

The nest-box portion similarly comprises three rectangular floor and wall panels 10, 11 and 12.

All six panels are of aluminium alloy sheet material, on the outer surfaces of which the rubber sheeting 5, 6 is secured by a slow-setting epoxy adhesive, although it will be appreciated that other rubber to metal adhesives may be used for this purpose.

The door flap 4 is hinged to the outer end of the floor panel 7, being shown in Figure 2 in the "trap set" position lying flat against the floor. The opposite end of the nest-box portion 2 is closed, when the trap is erected, by a triangular end wall 1 3 hinged to the adjoining edge of the floor panel 10 so that it lies flat with the latter in the collapsed condition. The flap 4 and end panel 1 3 are also of aluminium alloy sheet. The inner end of the floor panel 7 slightly overlaps the floor panel 10 to which it is secured, and again an epoxy adhesive may be used for this purpose. Thus the tunnel portion 1 projects for a short distance into the nest-box portion 2.

The rubber sheet 5 is secured to all three of the tunnel panels 7, 8 and 9 and its flexibility provides hinged interconnection of panels 7, 8 and 8, 9. It extends beyond the upper edge of the panel 9 as a flap 5a to which a Velcro fastening strip is secured, the complementary component of the latter being glued to the panel 8 adjacent the top edge thereof. Thus on erection of the trap the flap 5a is wrapped over the top ridge and provides a releasable Velcro fastening interconnecting the panels 8, 9 and maintaining the rigidity of the erected triangular shape. As can be seen from Figure 1, the other end of the rubber sheet 5 only partially overlaps the panel 8 with the thermal insulation of the latter completed by the Velcrosecured flap 5a.

In a similar manner the rubber sheet 6 hingedly interconnects the panels 10, 11 and 12 of the nest-box portion 2, and has a flap 6a providing a Velcro-fastening at the ridge of this portion to releasably interconnect the contiguous edges of the panels 11, 12. The sheet 5 has a flap Sb which extends at the outer end of the floor panel 7, this flap being secured to the outer surface of the door flap 4 which it partially overlaps. It provides three functions-thermal insulation of the door flap 4, a flexible hinge for the flap 4 and, due to its inherent resiliency, an effective spring force urging the flap 4 to the closed position.A similar flap of the rubber sheet 6, which is not shown, covers the end wall panel 1 3 for thermal insulation and hinged connection thereof. A flap 6a on the sheet 6 tucks into the side gap between the body portions 1 and 2, substantially sealing this gap while leaving adequate ventilation for the trap.

A trip mechanism for the door flap (Figure 2) comprises a treadle plate 14 hinged to the floor panel 7 close to the inner end thereof. In the trap set position it extends from the floor in an upward and inward direction, and a trip wire 1 5 in the form of a loop has its ends attached to the plate 14 at an intermediate height position at 1 6. The wire 15 is held down by a guide bracket 17 fixed to the floor panel 7 so that the end of the wire loop can just extend over, and hold down, the apex of the door flap 4. This restrains the flap 4 in the trap set position shown in Figure 2. The trap is erected with the door flap thus set, and an animal entering the trap and stepping on the plate 14 depresses the latter to trigger the trap and cause the wire loop 15 to slide below the bracket 17 and clear of the door flap 4, which is thus released and raised to the closed position by the inherent resilience of the hinge provided by the rubber flap Sb.

The described trap overcomes the transport problem with existing traps on two counts. Firstly, it collapses to a flat condition so that a large number of traps can be transported packed into a small volume; secondly, the materials used and the triangular shape which replaces the conventional rectangular shape results in low weight for a given effective size of trap.

Claims (12)

1. An animal trap having a body of triangular cross-section provided by a floor panel and two side wall panels, these three panels being hingedly interconnected at two pairs of contiguous edges and the other pair of contiguous edges being releasably interconnected to complete the triangular shape whereby release of these latter edges allows the body to be collapsed and transported in a substantially flat condition, the triangular entrance at one end of the body being closable by a triangular door flap hinged to the floor panel.

2. An animal trap according to claim 1, wherein the body has an entrance tunnel portion comprising said three panels and a nest-box portion which is of larger cross-section and similarly comprises three panels, the door flap being hinged to the floor panel at the outer end of the tunnel portion and the opposite end of the nest-box portion being closed by a triangular end wall hinged to the floor panel of that portion.

3. An animal trap according to claim 1 or claim 2, wherein said panels are of metal sheet.

4. An animal trap according to claim 3, wherein said panels are of aluminium alloy sheet for lightness and resistance to corrosion.

5. An animal trap according to claim 3 or claim 4, wherein said sheet metal panels have an outer layer of thermal insulation to protect trapped animals from adverse external temperature conditions.

6. An animal trap according to claim 5, wherein said insulation is of sheet material, such as rubber, attached to the panels by a suitable adhesive.

7. An animal trap according to claim 6, wherein said thermal-insulation sheet material provides the hinged interconnection of the panels.

8. An animal trap according to claims 2 and 7, wherein on each of said entrance tunnel and nestbox portions of the body a single sheet of thermal insulation extends around the three panels thereof, and overlaps the releasably interconnected panel edges where the insulation sheet is provided with a "Velcro" or like readily releasable fastening.

9. An animal trap according to any one of the preceding claims, wherein a hinge of elastomeric material such as rubber is provided for the door flap, the natural resilience of this material providing a door-closing spring force.

10. An animal trap according to any one of the preceding claims, wherein a triggered trip mechanism which holds the flap down in the open position when the trap is set includes a hinged treadle plate the movement of which, under the weight of an animal stepping on the treadle plate, releases a trip wire to free the flap.

11. An animal trap according to claims 2 and 10, wherein said treadle plate is hinged to the floor panel of said entrance tunnel portion.

12. An animal trap constructed and arranged substantially as herein particularly described with reference to the accompanying drawings.