GB2216764A

GB2216764A - Small animal trap

Info

Publication number: GB2216764A
Application number: GB8906078A
Authority: GB
Inventors: Brian White
Original assignee: Individual
Current assignee: Individual
Priority date: 1988-03-17
Filing date: 1989-03-16
Publication date: 1989-10-18
Also published as: GB8906078D0

Abstract

The trap comprises a housing 1 for placement in a path frequently taken by rats or other small animal pests, and has openings at opposite ends for entry of an animal from either direction. A hammer bar 25 is coupled to toggle bars 34, 36 and when the trap is primed the toggle bars are held by engagement of a pin 41 in a notch 45 in the edge of a catch plate 42. The catch plate is in turn held by a pin 22 which is secured to a trigger plate comprised in the floor of the housing. The hammer bar 25 is blassed downwards by a spring 29 so that when the weight of an animal on the trigger plate releases the catch plate 42 the hammer bar rapidly moves downwards to deliver a potentially fatal blow to the animal. <IMAGE>

Description

ANIMAL TRAP Most traps for disposing of rats or other small animal pests rely on tempting the animal into the trap using bait. This has the disadvantage that if there is a plenteous food supply in the area the animal is not inclined to investigate a strange trap. Furthermore, existing traps such as the fenn trap or the traditional mouse trap use a single hammer bar or a pair of hammer bars which swing upwards from a primed position into contact with the animal, and because the animal may be in any position relative to the hammer bar the animal is frequently caught alive by the feet for example rather than being killed outright.

According to one aspect the present invention proposes a trap for catching and killing rodents or other small animal pests, comprising a housing having an opening for entry of an animal into the housing, a hammer bar mounted in the housing and which, when the trap is in a primed condition, is held in a raised position such that an animal entering the housing will move beneath it, and trigger plate means comprised in a floor of the housing and operably connected to the hammer bar such that the weight of the animal on the trigger plate means causes the hammer bar to be released and move in a downward direction to deliver a potentially fatal blow to the animal.

According to a second aspect the invention proposes a trap for catching and killing rodents or other small animal pests, comprising a housing for placement in a path frequently taken by the animals and having openings at opposite ends for entry of an animal into the housing, a hammer bar mounted in the housing and which, with the trap in a primed condition, is held in a raised position such that an animal entering the housing from either end will move beneath it, and trigger plate means comprised in a floor of the housing and operably connected to the hammer bar such that the weight of the animal on the trigger plate means causes the hammer bar to be released and move in a downward direction to deliver a potentially fatal blow to the animal.

The invention will now be exemplified in the following description to be read in conjunction with the accompanying drawings in which: Figure 1 is a plan view of a rat trap in accordance with the invention, Figure 2 is section II-II of Fig. 1, Figure 3 is a side view of the trap shown in a primed condition, Figure 4 is a similar view to Fig. 3 but showing the trap in a sprung condition, Figure 5 is a diagrammatic plan view of a modified trap, and Figures 6a and 6b are plan views of two forms of modified hammer bar for use with the trap of Fig. 5.

Referring to Fig. 1, the trap comprises a housing 1 which includes a bottom wall 2, side walls 3, 4 and a top wall comprising a number of spaced parallel bars 5.

(In Fig. 1 the central bars are shown broken away for clarity.) Opposite ends 6, 7 of the housing are open so that the housing defines a through passage 8.

As can be seen in Fig. 2, the floor of the passage 8 is formed by two ramps 9, 10 which are upwardly inclined from the ends 6, 7 of the housing towards its middle region. The inner ends 11, 12 of the ramps are spaced apart and a trigger plate 13 is disposed substantially horizontally in the resulting gap. The trigger plate is carried between a pair of spaced generally horizontal arms 14 which extend towards the open end 6 and, at their opposite ends, are each pivoted at 15 to the side walls 3, 4. Thus, the trigger plate 13 is vertically movable through a few degrees about pivots 15. At the opposite end to pivot 15, one of the arms 14 is pivotally connected at 16 to a linkage 17, which rises to a pivotal connection 18 with a generally horizontal lever arm 19.This lever arm is pivotally connected at 20 part way along its length to side wall 3, and a counter weight 21 is mounted at its opposite end. The counter weight is arranged such that it applies a light lifting force to the trigger plate 13 via lever arm 19 and linkage 17.

At the opposite side of the trigger plate to the counter weight 21, a pin 22 extends from the trigger plate through a vertical slot 23 in side wall 4 (Fig.s 3 and 4), the purpose of which will be described below.

Referring back to Fig.s 1 and 2, the passage 8 also contains a transverse hammer bar 25. Two parallel limbs 26 extend from opposite ends of the bar and are each pivoted at 27 to the lower region of the respective side wall 3, 4. A second limb 28 (Fig.s 3 and 4) extends angularly from the pivoted end of one of limbs 26 at a steeper inclination. The hammer bar is rotatable about pivots 27 between a raised position shown in Fig. 3 to a lowered position shown in Fig. 4.

The hammer bar is biased towards the lower position by a spring 29 which is tensioned between a fixed stop 30 mounted on wall 4 in opening 7 and a further stop 31 (Fig. 1) disposed adjacent to the upper end of second limb 28 and rigid with the hammer bar.

The upper end of limb 28 carries a pivot pin 32 which extends through a downwardly curved slot 33 in side wall 4, along which the pin travels freely on movement of the hammer bar between its two positions. A first toggle bar 34 is pivotally connected to pin 32 externally of wall 4, the opposite end of this toggle bar being pivotally connected at 35 to one end of a second toggle bar 36. The other end of the second toggle bar is pivotally connected at 37 to side wall 4 and is secured to an upwardly extending portion 38.

The top of portion 38 extends above the rods 5 and is secured to a handle 39 which extends perpendicular to portion 38 in the opposite direction to toggle bar 36.

A striker pin 41 is secured to the second toggle bar 36 adjacent to pivot 35, to co-operate with an elongate catch plate 42. The catch plate is disposed on the opposite side of striker pin 41 to pivot 35 and its upper end is pivoted at 43 to side wall 4 slightly above the level of pivot 37. The left hand edge 44 of the catch plate cooperates with striker pin 41 and is substantially straight, but leads at its upper end into a notch 45 followed by a projecting ledge 46. At its lower end edge 44 leads into a curved nose 47 which ends in a longitudinally disposed shoulder 48. This shoulder is co-operable with pin 22 of the trigger plate, as described below.

The trap is placed in a path which is often frequented by the rats, ideally in an opening in a wall or on a roof beam for example where the rats have no option but to pass through it in order to obtain food.

As shown in Fig. 4, when the trap is in its sprung condition the hammer bar 25 is in its lower position under the action of spring 29, which brings the pivot 32 to the lower end of slot 33. The toggle bars are thus disposed in a V-configuration with the striker pin 41 urging the catch plate 42 to the right.

To set the trap the handle 39 is moved by hand to a horizontal position, which lifts the second toggle bar 36 towards a horizontal position. This in turn raises the first toggle bar 34 and moves the pivot 32 along the slot 33. As a result, the hammer bar is raised against the action of spring 29. As the toggle bar 36 moves upwards the striker pin 41 travels up the edge 44 of the catch plate and to the left so that the catch plate pivots under gravity towards a vertical position.

However, when the striker pin eventually engages the ledge 46 continued downward pressure on handle 39 causes the striker pin to exert a positive rotational force on the catch plate so that the nose 47 engages the pin 22 and urges it in a downward direction against the action of the counter-weight. When the nose 47 travels beyond the pin 22 the counter weight causes the trip plate 13 to rise and the pin 22 engages behind the shoulder 48 (see Fig. 3) preventing the catch plate from returning to its sprung position. Meanwhile, the continued rotation of the catch plate has caused the striker pin 41 to enter the notch 45, so that when the handle 39 is released the toggle plates are prevented from returning and the hammer bar is thus held in a raised position.It is to be noted that the toggle action of bars 34, 36, together with the fact that the striker pin 41 is located very close to the pivot point 43, results in only a small downward pressure on the catch plate 42.

When a rat travels in either direction through the passage 8 the trap is sprung by the downward pressure of its forefeet on the trigger plate 13. This moves the trigger plate in a downward direction so that the pin 22 moves out of engagement with the shoulder 48.

The catch plate is thus free to move to the right under the action of the striker pin so that the striker pin leaves the notch 45 enabling the toggle bars and hammer bar to rapidly return to the sprung position of Fig. 4.

The rapid downward movement of the hammer bar under the action of spring 29 delivers a potentially fatal blow across the neck of the rat which kills it virtually instantaneously. In fact trials have shown that the failure rate is exceedingly low and the vast majority of rats are killed outright with very little bleeding or suffering.

The trap can then be reset as described above so that the dead rat can be pulled or shaken out of the trap ready for re-use.

The bars 5 could be replaced by a solid top wall which is preferably removable for access to the interior of the trap. The use of a solid top wall may be preferable to the bars since it allows an air flow carrying the scent of food to be drawn through the passage 8 towards a passing rat.

In the modification of Fig. 5 the passage 8 contains a vertical partition wall 51 located centrally above the trigger plate 13 and running longitudinally of the passage beyond the front and rear edges of the trigger plate. This wall contains a curved slot (not shown) down which the hammer bar 25 can travel without hindrance. From each end of the partition wall 51 a row of vertical bars 52, 53 respectively, extend transversely of the passage to meet opposite side walls 3 and 4. A further row of vertical bars 54 and 55 also extend from the opposite ends of the partition wall to meet the respective side wall 3, 4 adjacent to the open ends 6, 7. It has been found, surprisingly, that the presence of these partitioning bars does not deter the rats from entering the trap.However, since the rat encounters the transverse rows of bars 52, 53 just beyond the trigger plate 13 there is no risk of its back legs triggering the trap instead of its front legs. The vertical bars 52-55 could be replaced with horizontal bars or a wire mesh.

Although the straight hammer bar of Fig.s 1 to 4 can be used in the modified trap of Fig. 5, it may be advantageous to use one of the modified hammer bars shown in Fig. 6. The hammer bar of Fig. 6a is cranked at 57 half way along its length so that the operative half 25a, 25b of the bar is advanced in the direction of the respective open end 7, 6. This ensures that even the smallest rats heads are sufficiently far forward when the trap is triggered for them to receive a fatal blow from the hammer bar. The hammer bar of Fig. 6b is straight as in Fig.s 1 to 4, but an additional hammer portion 58, 59 extending parallel with but spaced from the hammer bar 25 has been added at each end. These additional hammer portions are disposed on opposite sides of the bar staggered in the direction of the respective opening 7, 6. As well as advancing the operative portion of the hammer bar towards the incoming rat this arrangement also provides two-point contact with the rat to increase still further the prospects of a fatal blow being delivered.

Claims

1. A trap for catching and killing rodents or other small animal pests, comprising a -housing having an opening for entry of an animal into the housing, a hammer bar mounted in the housing and which, when the trap is in a primed condition, is held in a raised position such that an animal entering the housing will move beneath it, and trigger plate means comprised in a floor of the housing and operably connected to the hammer bar such that the weight of the animal on the trigger plate means causes the hammer bar to be released and move in a downward direction to deliver a potentially fatal blow to the animal.

2. A trap for catching and killing rodents or other small animal pests, comprising a housing for placement in a path frequently taken by the animals and having openings at opposite ends for entry of an animal into the housing, a hammer bar mounted in the housing and which, with the trap in a primed condition, is held in a raised position such that an animal entering the housing from either end will move beneath it, and trigger plate means comprised in a floor of the housing and operably connected to the hammer bar such that the weight of the animal on the trigger plate means causes the hammer bar to be released and move in a downward direction to deliver a potentially fatal blow to the animal.

3. A trap according to Claim 1 or 2, in which the hammer bar is spring-biassed in a downward direction.

4. A trap according to any preceding claim, which includes first and second toggle bars pivotally connected together, the first toggle bar having a pivotal connection with the hammer bar and the second toggle bar having a fixed pivot.

5. A trap according to Claim 4, which includes a catch plate having a fixed pivot, the catch plate being arranged to be held in a primed position by the trigger plate means and thereby to retain the toggle bars in a primed position in which they in turn hold the hammer bar in its raised position, and when the weight of an animal operates the trigger plate means the catch plate is released which in turn releases the toggle bars to allow the hammer bar to move in a downward direction.

6. A trap according to Claim 5, in which the catch plate holds the toggle bars in the primed position by engagement of a projection carried by the toggle bars in a notch in an edge of the catch plate.

7. A trap according to Claim 6, in which movement of the hammer bar to the raised position to prime the trap causes the said projection to travel along an edge of the catch plate until it engages in the said notch.

8. A trap according to Claim 7; in which the notch is arranged such that engagement of the pin therein causes the catch plate to pivot into engagement with the trigger plate means.

9. A trap according to any of Claims 4 to 8, in which the second toggle bar is connected to a handle for moving the hammer bar into the raised position.

10. A trap according to any preceding Claim, in which the trigger plate means includes bias means for biassing the trigger plate into a raised position.

11. A trap according to Claim 10, in which the bias means comprises a counter weight arrangement.

12. A trap according to any of Claims 3 to 11 as appended to Claim 2, in which the housing contains internal dividing walls which direct an animal entering the trap from one end beneath one end portion of the hammer bar and which direct an animal entering from the opposite end of the housing beneath the other end portion of the hammer bar.

13. A trap according to Claim 12, in which the internal dividing walls are at least partially of skeletal form to permit an air flow through the housing.

14. A trap according to Claim 12 or 13, in which the said end portions of the hammer bar are staggered in the direction of approach of the animal.

15. A trap which is substantially as described with reference to the drawings.