GB2293956A - Animal trap - Google Patents

Abstract

An animal trap comprises a rectangular enclosure 5 for captured animals having an entry port 6 and containing an attractant 11 for the target animal. The enclosure contains a pivoted rectangular platform 7 which rests on a pivot 8. The entry end of the platform is biased so that in its 'set' position it rests, under the influence of gravity, along the lower edge of the entry port (Fig. 2a). Magnetic catches 12, 13 and 21, 22 are attached to each end of the platform. When the platform bias is overcome and the ends are tipped towards the magnets, the catches cooperate to lock the platform in its 'sprung' position (Fig. 2b). The platform can be further secured by, means of a locking plate (not shown) fixed hingeably to the underside of the platform near the entry. The trap includes an alarm activated by the change from the set to the sprung state. The alarm may be remote sensed. <IMAGE>

Description

ANIMAL TRAP This invention relates to animal traps and particularly to traps that are capable of capturing animals without injury.

For the purposes of pest control and for research it is often necessary to capture animals and in some cases destroy them. For the control of rodents trapping is frequently the preferred method of destruction as, unlike poisoning, no immunity arises. Rodent traps are widely known which capture animals causing injury or death but their action is indescriminate.

There is a need for rodent traps which do not harm the captured animal so that it can be identified and only destroyed if a harmful species. A number of rodents, e.g.

Muscardinus avellanarius, are protected and trapping in areas where they occur should only involve non-lethal traps. In areas where both grey squirrels and red squirrels occur it is essential that the trapped animal is identified before release or destruction; the fate of the animal is species dependent.

The present invention provides an animal trap which, in various embodiments, can be arranged to capture without injury a wide range of animals of different sizes and species. While it is primarily intended for the capture of small mammals, particularly rodents, it may also be used to capture avian and reptilian species.

According to the present invention there is provided an animal trap comprising a rectangular enclosure for captured animals having an entry port and containing an attractant for an animal, characterised in that the enclosure contains a pivoted rectangular platform of substantially similar width to that of the enclosure, which rests on a pivot and having a first, entry, end which is biased so that in its 'set' position it rests, under the influence of gravity, along the lower edge of the entry port and a second, rearward, end in an elevated position, magnetic catch means consisting of at least one magnet attached to the enclosure and a cooperating ferromagnetic catch plate attached to an end of the platform so that, when the platform bias is overcome and the end is tipped towards the magnet, the catch plate cooperates with the magnet to lock the platform in its 'sprung' position.

Preferably the pivot is located substantially centrally with respect to the platform and the ferromagnetic catch plate is located on the underside of the rearward end.

It will be seen that the platform will be tipped by an animal when it moves alongs its surface towards the attractant. Due to the locking effect of the magnet and catch plate the platform will not return to its set position even if the animal attempts to retreat. In the case of large animals or those capable of violent movement the magnet and catch plate combination may be duplicated by placing a second magnet near the top of the entry port with a cooperating catch plate on the upper surface of the platform near the entry end. The locking of the platform may be further secured by means of a locking plate fixed hingeably to the underside of the platform near the entry end. In its set position the locking plate will lie substantially horizontally below the platform resting on the base of the enclosure.When the platform is tipped the locking plate will remain in contact with the base by gravitational action but in a substantially vertical position and restrain movement of the platform. Preferably a small block is fitted to the base of the enclosure to act as a ratchet and prevent the base of the locking plate slipping. The platform is locked in its sprung position by the locking plate even though the trapped animal is capable of exerting sufficient force to separate the magnet and associated catch plate.

The size of the trap will depend upon the maximum size of the target animal it is proposed to capture. The entry port must have a width and height adequate to allow passage of the target animal. The platform will have a width substantially the same as the width of the entry port. The length of the platform and the height of the pivot above the base will determine the vertical distance between the entry end in its set state and in its tipped state. This distance must be substantially equal to the height of the entry port. The choice of dimensions usually involves a low position for the pivot with respect to the base of the enclosure and a relatively long platform so that the upward slope of the inward path to the attractant does not deter a target animal. A slope in the range 50 to 250 is usually acceptable.The upper surface of the platform may be roughened or carry ridges to assist the entry of wide bodied small footed animals such as hedgehogs (Erinaceus europaeus). In order to reduce sensitivity and prevent the platform tipping until the target animal is well past the pivot point some frictional contact between the sides of the platform and the sides of the enclosure may be advantageous.

The attractant or lure will usually be bait such as food to which the target animal is partial. Alternatively the attractant may be a light or sound emitting device or a container of an appropriate pheromone.

The mass and location of the bait will affect the equilibrium of the platform so that adjustment means are preferably provided to compensate for its presence. The compensation is preferably provided by a moveable counterweight below the platform and close to the entry end.

The components of the trap may be constructed from a variety of materials according to the size and environment in which it is to be used. The enclosure portion and the platform may be fabricated from plywood sheet having a thickness adequate to resist attack by any captured animal.

In a preferred embodiment the trap has an upper wall or at least on side wall formed from a transparent material, such as polymethacrylate sheet, to assist setting the trap and to enable identification of any captured animal before release or destruction. The side walls should carry perforations to ensure sufficient air enters the enclosure to prevent suffocation of any captured animal.

The platform may rest on a fulcrum formed from a steel rod or tube or a portion of wood dowel. The platform may be held in position by a two rows of pins projecting downwardly, a pair of angle plates or a pair of blocks attached to its underside. Such an arrangement permits easy removal of the platform for cleaning. Alternatively the platform may be attached to a hinge whose central rod acts as the fulcrum.

In a particulary preferred embodiment the upper wall of the enclosure carries a hinged door to assist the release of any captive animals. The trap may carry alarm means activated by the change from the set to the sprung state so that rapid action can be taken in the event of a capture.

The alarm means may comprise a lamp which is energised by a battery through a switch operated by the platform. The alarm may have transmission facilities sending a signal to a remote receiver denoting operation of the trap.

In order that the invention may be clearly understood it will now be described with reference to the accompanying drawings in which: Figure la shows a cross sectional side view of an animal trap according to the invention in its 'set' condition, Figure Ib shows the trap of Figure la in its 'sprung' condition, Figure 2a shows a cross sectional side view of an alternative embodiment of an animal trap according to the invention in its 'set' condition, and Figure 2b shows the trap of Figure 2a in its 'sprung' condition.

An animal trap according to the invention, see Figure 1, consists of an enclosure 1 formed by an upper wall 2, a side wall 3, an end wall 4, a further side wall parallel to side wall 3, not shown, and a base 5. An entrance 6 permits ingress to the container 1. A platform 7 within the container 1 is pivotably mounted on a fulcrum 8. The platform 7 is biased to an extent that its front end 9 rests substantially at the base of the entrance 6 under the influence of gravity; the trap is in its 'set' state. The platform 7 has a rear end 10 located within the container 1. The platform 7 carries an attractant or lure 11 close to the end 10. The base 5 carries a magnet 12 and the platform 7 carries a small catch plate 13, formed from a ferromagnetic material, on its underside near to the end 10.

The platform 7 in its set state forms an upwardly sloping path from the entrance 6 to the rear end 10 carrying the attractant 11. When a small rodent or other animal enters the container 1 it moves along the surface of the platform 7 towards the attractant 11. As it crosses the fulcrum 8 the equilibrium of the platform will be altered and the rear end 10 will move downwardly towards the base 5 of the container 1. When end 10 of the platform 8 reaches the base 5 the magnet 12 engages the plate 13. The strong attractive force between the magnet 12 and the plate 13 locks the platform 7 in its 'sprung' state and ensures that it cannot return to its set state even if the rodent moves towards the end 9.

The size of the trap will depend upon the maximum size of the target animal it is proposed to capture. The entrance 8 must be have a width and height adequate to allow passage of the animal. The platform 7 will have a width substantially the same as the width of the entrance 8.

The length of the platform 7 and the height of the fulcrum above the base 5 will determine the vertical distance between the end 9 in its set state and in its tipped state.

This distance must be substantially equal to the height of the entrance 8. The choice of dimensions usually involves a low position for the fulcrum 8 and a relatively long platform 7 so that the steepness of the inward path to the attractant does not deter the target animal. A slope in the range 50 to 250 is usually acceptable. The surface of the platform 7 may be roughened or carry ridges to assist the entry of wide bodied small footed animals such as hedgehogs.

The attractant or lure 10 will usually be bait such as food to which the target animal is partial. The mass end location of the bait 10 will affect the equilibrium of the platform so that adjustment means are preferably provided to compensate for its presence. The compensation is preferably provided by a moveable counterweight below the platform 7 and close to the end 9.

In a second embodiment, see Figures 2a and 2b, where like numbers designate the same items as Figure 1, upper wall 20 slopes from the top of the rear wall 4 to the top of the entrance 6. Apart from saving material during construction this arrangement of the upper wall 20 reduces the volume within the enclosure 1 available to any captured animal when the trap is in its sprung state.

In order to increase the stability of the platform 7 in its sprung state, particularly important when larger rodents are involved, the upper wall 20 carries a magnet 21 and the platform 7 carries a small catch plate 22, formed from a ferromagnetic material, on its upper surface near to the end 9. When the passage of a target animal past the fulcrum 8 causes the equilibrium of the platform 7 to alter. The rear end 10 moves downwardly and the magnet 12 engages the plate 13. At the same time the front end 9 moves upwardly and the magnet 21 engages the catch plate 23. The strong attractive forces between the magnet 12 and the plate 13 together with the forces between the magnet 21 and the plate 23 locks the platform 7 firmly in its 'sprung' state and ensures that it cannot return to its set state regardless of the movements of the trapped beast.

Practical embodiments of the animal trap shown in Figures 2 have been manufactured and successfully tested for mice and squirrels. In the case of the mouse trap the platform was cut from 4 mm resin bonded plywood with a width of 50 mm and a length of 300 mm. The platform enclosed in a container having an internal width slightly in excess of that of the platform width. The side walls were cut from 4 mm plywood and the end wall, the upper wall and base were cut from 10 mm wood; the side wall were attached by nails.

A portion of the upper wall was cut away and covered with a perforated transparent sliding lid so that the species of trapped animal could be observed and identified without any need to handle it. The platform rested centrally on a 10 mm diameter dowel and was restrained from sliding by downward facing pins on the underside of the platform.

The balance was biased to the set position by small weights attached to the underside of the platform. The trap proved extremely effective in catching various species of mouse including Mus musculus and Apodemus sylvaticus.

In the case of the squirrel trap all the dimensions were approximately doubled. The end wall, the upper wall and base were cut from wood as before but the side walls were cut from polymethylmethacrylate sheet and attached to the other walls and base by screws. A portion of the upper wall was cut away, as described previously, to permit easy access to any trapped animal. The transparent sides provided a number of benefits, the species of a trapped animal be identified immediately, the ability to see through the sides encouraged squirrels to enter the trap and also reduced their alarm on entrapment. Due to the size and power of the target animal a second magnet and catch plate was fitted near the top of the entry port with a cooperating catch plate on the upper surface of the platform near the entry end. The locking of the platform in its sprung position was ensured by means of a locking plate attached by a small metal hinge to the underside of the platform near the entry end. The locking plate was cut from wood having the same width as the platform and sufficient length that its free end just touched the base when the platform was in the sprung position and the plate hanging vertically.

As the platform tipped the free end of the locking plate slid over the base until it hung in a substantially vertical position. A small block of wood attached to the base prevented the free end of the locking plate from sliding back to its set position.

Claims (18)

1. An animal trap comprising a rectangular enclosure for captured animals having an entry port and containing an attractant for an animal, characterised in that the enclosure contains a pivoted rectangular platform of substantially similar width to that of the enclosure, which rests on a pivot and having a first, entry. end which is biased so that in its 'set' position it rests, under the influence of gravity, along the lower edge of the entry port and a second. rearward, end in an elevated position, magnetic catch means consisting of at least one magnet attached to the enclosure and a cooperating ferromagnetic catch plate attached to an end of the platform so that, when the platform bias is overcome and the end is tipped towards the magnet. the catch plate cooperates with the magnet to lock the platform in its 'sprung' position.

2. The animal trap as claimed in claim 1, characterised in that the pivot is located substantially centrally with respect to the platform and the ferromagnetic catch plate is located on the underside of the rearward end.

3. The animal trap as claimed in claim 1 or claim 2, characterised the magnet and catch plate combination is duplicated by placing a second magnet near the top of the entry port with a cooperating catch plate on the upper surface of the platform near the entry end.

4. The animal trap as claimed in any of the preceding claims, characterised in that the locking of the platform is further secured by means of a locking plate fixed hingeably to the underside of the platform near the entry end.

5. The animal trap as claimed in any of the preceding claims, characterised in that a small block is fitted to the base of the enclosure to act as a ratchet and prevent the base of the locking plate slipping.

6. The animal trap as claimed in any of the preceding claims, characterised in that the slope of the platform lies in the range EO to 250

7. The animal trap as claimed in any of the preceding claims. characterised in that the upper surface of the platform is roughened or carries ridges.

8. The animal trap as claimed in any of the preceding claims. characterised in that frictional contact is provided between the sides of the platform and the sides of the enclosure.

9. The animal trap as claimed in any of the preceding claims. characterised in that a moveable counter-weight is provided below the platform on the entry end side.

10. The animal trap as claimed in any of the preceding claims, characterised in that the trap has an upper wall or at least on side wall formed from a transparent material.

11. The animal trap as claimed in any of the preceding claims, characterised in that the side walls carry perforations to allow the entry of air.

12. The animal trap as claimed in any of the preceding claims. characterised in that the platform rests on a pivot and is held in position by two rows of pins projecting downwardly. a pair of angle plates or a pair of blocks attached to its underside.

13. The animal trap as claimed in any of the preceding claims, characterised in that the upper wall of the enclosure carries a hinged door.

14. The animal trap as claimed in any of the preceding claims, characterised in that the trap carries alarm means activated by the change from the set to the sprung state.

15. The animal trap as claimed in claim 14, characterised in that the alarm means comprises a lamp which is energised by a battery through a switch operated by the platform.

16. The animal trap as claimed in claims 14 or 15, characterised in that the alarm means includes transmission facilities for sending a signal to a remote receiver when the alarm is activated.

17. Animal traps as claimed in claim 1 and as herein described.

18. Animal traps as herein described with reference to the accompanying drawings.