Bird-scare Cannon With Ball Recovery

Abstract

Cannon for scaring birds and other undesirable creatures, comprising an elongated reservoir wherein a plurality of balls is stored and which can be pressurized. The balls are expelled one by one when the air pressure in the reservoir attains a value capable of foregoing one ball through an orifice in the reservoir wall, overcoming the resisting frictional force between the orifice and the ball. Either the balls or the orifice wall can be made elastic or deformable while the other element is made relatively rigid or nondeformable. A recovering device is associated with the cannon, consisting of a circular tube into which the balls expelled by the cannon are shot, and from where they may be discharged into a container or the like.

Parent Case Text

This is a divisional of the application Ser. No. 655,634, filed July 24, 1967, entitled "Air Gun," now U.S. Pat. No. 3,572,309 of Mar. 23, 1970 of the same invention titled Air Gun.

Description

This invention refers to a cannon which is adapted to produce explosions or detonations automatically and at predetermined intervals in order to scare birds and other undesirable creatures the presence or occurrence of which should be avoided in a certain area.

It is an object of the invention to provide a cannon which employs an assembly of reservoirs fed by an air compressor, one of said reservoirs containing a series of elastic balls or spheres, each of which, upon being pressed against the muzzle of the cannon by the gradually increasing air pressure, and unable to resist such a pressure, is violently expelled through said muzzle, and as a consequence, produces an explosion or loud noise.

The explosion is complete and unique, that is, the evacuation of the compressed air is effected totally and at once because another ball, which forms part of the load of the cannon, will not occlude the cannon muzzle nor produce a second consecutive shot or explosion before the substantially total evacuation takes place that caused the explosion.

To this end the cannon is provided with a device which locks in place all the balls which are contained in the cannon during the complete period in which the compressed air is exhausted.

The cannon is further provided with another device which, upon evacuation of compressed air from the reservoir, positions another ball in the cannon muzzle and presses the same against the muzzle to prevent any leakage of air so that said ball may cause the compressor to raise the pressure inside the cannon for a new explosion.

In order that the balls might be reused and maintained within a container or the like until such use, the cannon is preferably provided with a device which captures and stores the expelled balls.

The loudness of the explosions or detonations may be increased or decreased at will within a fairly wide range simply by substituting the balls by other balls somewhat bigger or smaller, harder or softer, in accordance with the desired result. The frequency of the explosion may be increased or decreased by admitting more or less compressed air into the cannon, by controlling a simple valve associated with the air compressor.

Inasmuch as the mechanism of the cannon comprises only a simple paddle in addition to a small compressor, and the only consumption of energy is the electricity for operating a motor, the cannon of the invention is of very economical maintenance.

According to an important feature of the invention, the cannon comprises reservoir means which may consist of two reservoir portions and a chamber portion, the first reservoir portion containing compressed air, the second reservoir portion containing the balls together with compressed air, and the chamber portion being fitted with a pivotable paddle member above an orifice which constitutes the muzzle of the cannon.

According to another important feature, the cannon may have an auxiliary reservoir from which a high-velocity air jet is applied to one side of the paddle member. This is preferably convex, while the air jet delivered from the first reservoir portion impinges upon the concave side of the paddle member.

According to yet another feature of the invention, recovering means can be used in conjunction with the cannon, for gathering the balls expelled with each explosion, and comprising a circular tube with two openings namely for receiving and for discharging the balls. Clamp means may be provided on the tube for diminishing the radius of curvature and for preventing the balls from exiting through the receiving opening during their rotation within the tube. An appropriate container may be disposed underneath the discharging opening, for storing the collected balls.

The various objects, features and attendant advantages of the present invention will become more apparent from the following detailed description of a preferred exemplary embodiment of a bird-scare cannon, when considered in conjunction with the accompanying drawing, wherein

FIG. 1 represents a somewhat schematical longitudinal sectional view of the bird-scare cannon according to the invention, showing the portion thereof which produces the shots or explosions;

FIG. 2 is a similarly schematic plan view of a recovering device preferably associated with the cannon shown in FIG. 1, for capturing and storing the expelled balls before reuse; and

FIG. 3 is a similarly schematic longitudinal sectional view, somewhat similar to that of FIG. 1 but on an enlarged scale, concentrating on the essential inner mechanism of the cannon, as will be described in detail.

As shown in FIG. 1, the bird-scare cannon according to the invention, in a preferred, exemplary embodiment, includes a reservoir 1 for compressed air, a reservoir 2 for elastic balls 7 and compressed air, a chamber of distribution or discharge 3 which connects the two above-mentioned reservoirs, and an auxiliary reservoir 4 which is disposed adjacent and liked to the body of reservoir 2 by means of a T-connection 5 (see FIG. 3).

At one of its ends, the reservoir 2 is provided with an airtight door 6 through which the elastic balls 7 may be introduced. The chamber 3 is provided with a washer 8 which has a central perforation or orifice 9 constituting a muzzle for the cannon and which has a diameter somewhat smaller than that of the balls 7.

The chamber 3 is provided with a paddle 10 capable of swinging a certain angle around a pivot 11, capable to adopting the broken line position 10' (FIG. 3 also shows that the pivot 11, which can also be a shaft, is supported in chamber 3 by a support member 12). The reservoir 4 is connected with the reservoir 2 by means of a tube 13 of small diameter, located in a washer 14 which separates the reservoirs 2 and 4.

The reservoirs 1, 2 and 4 and the chamber 3 are fed by an air compressor 15. The pressure of the compressor is indicated by a manometer or pressure gage 16.

A used tire tube 17 or the like member, which has an elliptical opening 18 the minor axis of which is slightly bigger than the diameter of one of the balls 7, and the major axis of which is somewhat bigger than said diameter, and another opening 19 having a diameter slightly bigger than that of the balls 7, is preferably arranged underneath or in the direction of the cannon muzzle 9 so that the center of the elliptical opening 18 falls into a vertical line passing through the center of the muzzle or orifice 9.

A box 20 the lid of which has an opening 21 is arranged beneath the tube 17, as shown, so that the openings 19 and 21 align. Some of the less important structural elements will be described somewhat later as the description proceeds.

In short, the operation of the bird-scare cannon is as follows: Let us assume that one of the balls 7 is closely adjacent to or closing the muzzle 9 of the cannon and that the air compressor 15 raises the pressure of the system to a point such that the one ball is projected outside of the muzzle 9, causing an explosion or detonation. The explosion of the air contained in reservoir 1 will cause the paddle 10 to occupy the position 10', swinging about pivot 11 and preventing, in this position, that the following ball 7 may close the muzzle 9.

As a consequence, the manometric pressure of the system will drop to zero and the air which had been compressed in reservoir 4 will escape, with some delay, through tube 13, and will urge the next ball 7 toward the muzzle 9, once the paddle 10 loses its action as soon as the explosion phase ends. Besides, the air coming from reservoir 4, streaming in at a delivery rate which is large with respect to that of the compressor 15, will reestablish a certain pressure in the system and which, although small, will be enough to cause the next ball 7 to be pressed against the muzzle 9 and to close again the system hermetically.

The compressor 15, constantly in operation, will raise again the pressure of the system until the new ball 7, now located in the orifice 9, is unable to resist the high pressure of the system and provokes a new explosion upon being expelled.

The capture of the balls 7, expedient for economic reasons, will be understood from FIG. 2. The ball 7 expelled by the cannon of FIG. 1 falls into the center of the elliptical opening 18, if the tube 17 is properly positioned with respect to the orifice 9; it gets inside the tube 17 and moves around the inside wall thereof. The ball gradually loses the kinetic energy which was transmitted thereto by the potential energy of the compressed air and, when said kinetic energy is zero and the ball is only subjected to gravity, it is compelled to fall into box 20, passing through openings 19 and 21.

A screw 22 which is threaded in a clamp 23 may be provided to diminish the radius of the curvature of the tube 17 a short distance before the opening 18 so as to avoid that the balls 7 may get out through this opening in the case that they lose their kinetic energy or momentum shortly before reaching the edges of said opening 18.

Having thus explained in general lines the operation of the cannon and of the ball-recapturing device associated therewith, the actions will now be discussed in more detail which take place during the explosion phenomenon. To this end, the data will be discussed which the inventor gathered in a bird-scare cannon built according to the present invention, to verify the materialization of the idea that originated the invention, after eliminating a series of unforeseen results which are the systematic, unavoidable and unseparable companions of all inventions.

In this respect, reference should be had to FIG. 3 which shows a preferred, exemplary embodiment of the cannon built with conventional, readily available parts. For the compressed-air reservoir 1 the inventor used a water pipe 3 inches in diameter and approximately 1551/2inches (3.95 meters) long, also shown partially in FIG. 3. For the second reservoir 2, he used the same 3 inch pipe in a length of approx. 72 in. (1.83 m.), also partially shown in FIG. 3. He interconnected these two pipes by means of two 3 inch T-joints, one having its third leg directed downwardly in order to serve as the discharge or distribution chamber 3, and the other having its third leg directed upward (see numeral 5 in FIG. 3) to receive the auxiliary reservoir 4.

In one of the mouths of the first T-joint, the inventor placed a washer 24 having a central opening 11/2 inch in diameter and in which he adapted a nozzle 25. In the free mouth of this T-joint he attached the washer 8 having the orifice 9 which constitutes the muzzle of the cannon. The diameter of this orifice is approximately 21/8 in. (54 millimeters) when the diameter of the balls 7 employed in this preferred embodiment is approx. 21/2 in. (65 mm.).

In the central line of this T-joint, indicated with the letters X-X' in FIG. 3, he installed the paddle 10 capable of swinging about the pivot 11 mounted on the support 12. In the T-joint 5 which has one leg directed upward, he placed the washer 14 provided with the small tube 13 being five thirty-seconds inch in diameter.

In the same leg of the T-joint 5, he attached the pipe 4 constituting a reservoir, 3 inches in diameter and approximately 231/2 in. (60 centimeters) long. The free end of pipe 4 is closed by a cap or other conventional means (see FIG. 1).

A small compressor 15, e.g., the kind used for touchup spray-painting jobs, of 1/3 HP, was connected to one end of the pipe 1 which end was closed by a cap.

The cannon thus built was loaded with 30 solid balls 7 made of very elastic rubber, approximately 21/2 in. in diameter and weighing approximately 6 ounces (approx. 175 grams) each. These balls are preferably of the type used as toys by children.

The cannon took 21/2 hours to shoot the 30 balls, thus giving a shot or explosion about every 5 minutes. When the air inlet of the compressor 15 was provided with a cap, having an opening of approx. one sixty-fourth inch (0.5 mm.) in diameter, the cannon took 15 hours to shoot the 30 balls, thus giving a shot every 30 minutes. The average pressure of the individual shots was 5 atmospheres (manometric).

The computation of the cannon dimensions, due to its length and elaboration, is omitted since they are not really critical. Nevertheless, some of the dimensions will be mentioned as a matter of example when deemed useful for the better understanding of further operational features of the inventive bird-scare cannon.

Following the examination of the operation, in its most important details, let us consider, with reference to FIG. 3, the three axes X-X', Y-Y' and Z-Z'. On axis X-X', the ball 7 shown in solid lines and indicated with the reference x, represents the position that the ball occupies when the air in the chamber 3 is not compressed. In this phase, the paddle 10 will have a more or less restricted space between the washer 24 and the ball x but enough to permit that this ball may freely occupy its place in the muzzle 9. In this phase, the following ball, also shown in solid lines and indicated with the reference Y, will rest against the ball x.

When the air is highly compressed, the ball x will adopt the position and shape shown in broken lines and indicated with the reference x'. It will be noted that the ball is undergoing a pronounced flattening, as shown, and its contour is in contact with the edges of the orifice 9 in washer 8. When the ball x' is in this position, the ball Y will move to the position shown in broken lines and indicated by the reference Y', on axis Y-Y'.

Naturally, the paddle 10, which can swing freely, inasmuch as it is mounted on the pivot 11, will fall a certain amount due to the action of gravity, and maintain contact with the ball x'. Suddenly, with the increasing pressure transmitted by the air, the ball x' will be violently projected through the muzzle 9 of the cannon. This of course causes the explosion or detonation, adapted to scare the birds or other creatures.

It is useful to note at this point that, in accordance with the computations referred to above, the median velocity of the air jet at the outlet of pipe 1, and which impinges on the concave face of the paddle 10, is approx. 1,085 feet per second (331 meters per second) while the median velocity of the air jet at the outlet of tube 2 is 164 ft./sec. (50 m./sec.).

It should be noted that the pressure exerted by a jet or air on a flat surface perpendicular to its direction varies with the square of its velocity and, on the other hand, that the pressure of a jet of air is approximately four times higher on the concave side of a hollow sphere than on its convex side. For these considerations, the paddle 10 is preferably given a shape which approximates that of a hollow sphere, as illustrated.

Therefore, paddle 10 which is subject to the action of two different jets of air, as described before, will abandon its position to the left of axis X-X' (as viewed in FIG. 3) to occupy the position shown in broken lines and indicated by 10'. During this movement, the paddle 10 will shift the ball Y' from axis Y-Y' to axis Z-Z' and will maintain the ball 7 on this axis until the end of the explosion.

Once the explosion has taken place, the paddle 10, now free of any retention force in the direction to the right of axis X-X', will hang substantially parallel to this axis. The air gushing from reservoir 4 will then move the ball 7 from axis Z-Z' to axis X-X' and cause the ball to fall into the muzzle 9.

Inasmuch as the stream of air has a delivery rate relatively high as compared to the very low delivery rate of the compressor, it will communicate to the system a pressure which is low but high enough to press the ball against the cannon muzzle, and thus create a hermetic seal thereat.

According to the computations and tests relative to the preferred exemplary embodiment of the inventive bird-scare cannon, the duration of the explosion is of 0.13 second, the pressure decreasing from about 5 atmospheres to atmospheric pressure. According to the same tests, the draining of reservoir 4 to 5 atmospheres to atmospheric pressure takes place in about 1.8 second, that is to say 1.7 second after the explosion takes place. However, the ball, in its path through positions 7-Y-Y', does not fall immediately in the cannon muzzle 9, to position x, and a good portion of the air stored in reservoir 4 leaks to the atmosphere. Assuming a 50 percent loss of this air, it will still remain, according to the tests and computations, approx. 0.27 cubic feet (0.00775 m..sup.3) of free air. The three reservoirs 1, 2 and 4 of the cannon have a total volume of approx. 1.1 cubic feet (0.0316 m..sup.3) with an average charge of balls. This volume of 0.27 cu. ft., distributed in all the reservoirs, will produce a pressure of 1.25 atm. a. This pressure is sufficient to retain a ball in the muzzle until the compressor raises the pressure.

It will be apparent that substantially the same effect would be achieved if the balls were rigid or indeformable and the cannon muzzle were deformable or elastic. It should be borne in mind that the concept of the invention resides in providing an explosion of compressed air in a reservoir the muzzle of which is obturated by a ball having a diameter greater than that of the muzzle, and which will be expelled through said muzzle when the value of the compressed air pressure reaches a predetermined level; and, upon the ball being expelled and having produced the explosion or detonation required for scaring undesirable birds, it will be automatically substituted by another ball which, in turn, will remain waiting until the compressor raises again the pressure in the reservoir, after a period of time to be selected at will, as required, and/or in accordance with the delivery rate of the compressor. The operation of the compressor may be continuous or intermittent, the latter for example if the compressor is controlled by a relay or other conventional control means.

The foregoing disclosure relates only to a preferred exemplary embodiment of the bird-scare cannon, which is intended to include all changes and modifications of the example described, within the scope of the invention as set forth in the appended claims.

It will be understood, for example, by those skilled in the art that the structural details of the cannon and of the associated recovering device may constructed in other ways than described. The connection and correlation of the parts may be altered by using different structural elements performing substantially in the same manner.

The inlet door for introducing the balls into the reservoir may be located closer to the orifice than shown in the drawing; the reservoir portion holding the balls may be given a slight inclination so as to allow the balls to roll therealong by gravity; biasing means may be provided for the paddle so as to assist the effect of the two air jets, and other similar minor changes may be made in the invention.

It will be understood from the preceding specification that the auxiliary reservoir 4 must have communication, e.g., by means of the tube 13 of small diameter, with the reservoir portion 2 which holds the balls 7, the reservoir portion 1 for the compressed air, and with the chamber 3 of distribution or discharge.

Claims

What I claim is:

1. A bird-scare cannon, comprising: airtight reservoir means adapted to contain a plurality of balls of a specific diameter, and provided with an airtight door through which said balls can be introduced; said reservoir means also having a portion formed with an orifice having a diameter slightly smaller than that of said balls; one of said reservoir means portion, on the one hand, and said balls, on the other hand, being of an elastic material yielding to the material of the other; said orifice constituting the muzzle of the cannon; wherein said orifice does not allow passage of said balls therethrough when the air pressure within said reservoir means is in the range of atmospheric pressure, and permits the passage of one ball when said balls, one after the other, are seated on said orifice and occlude the same hermetically; means for periodically compressing the air inside said reservoir means until said air pressure attains a value capable of transmitting to said one ball, when seated on said orifice and pressed thereagainst, a force higher than the resisting frictional force between said orifice and said one ball; whereby said balls are periodically expelled from the cannon, one after the other, with the production of an explosion which is adapted to scare away birds and other creatures, and means for recovering said balls upon having been expelled from the cannon, including: a substantially circular tube having a first opening for receiving said balls which subsequently rotate within said tube owing to their kinetic energy; and a second spaced-apart opening for discharging said balls from said tube; said openings as well as said tube having a diameter larger than that of said balls; said recovering means being disposed at a shooting distance from the cannon so that said first opening faces said orifice; and said second opening being disposed at a lowermost point of said tube.

2. The bird-scare cannon as defined in claim 1, further comprising adjustable clamp means at least partly surrounding said circular tube a short distance away from said first opening, for diminishing the radius of curvature of said tube and thus for preventing said balls from exiting through said first opening during their rotation within said tube.

3. The bird-scare cannon as defined in claim 1, further comprising container means with an opening, disposed so as to be underneath said second opening of the circular tube, whereby said balls are collected in said container means by gravity after they have lost their kinetic energy during their rotation within said tube.