US3039450A - Vacuum gun - Google Patents

Description

T. J. SCALA June 19, 1962 VACUUM GUN 2 Sheets-Sheet 1 Filed Aug. 6, 1959 FIG. 2

FIG. 5

THOMAS J. SCALA INVENTOR ATTORNEY T. J. SCALA June 19, 1962 VACUUM GUN 2 Sheets-Sheet 2 Filed Aug. 6, 1959 THOMAS J. SCALA INVENTOR ATTORNEY United States Patent 3,039,450 VACUUM GUN Thomas I. Scala, Lake Hopatcong, N .J., assignor to Astrosysterns, Incorporated, Livingston, NJ a corporation of New Jersey Filed Aug. 6, 1959, Ser. No. 831,993 7 Claims. (Cl. 124-11) This invention relates to a vacuum gun for throwing a projectile through the air to a point some distance from the gun barrel. It has particular reference to a gun which operates without explosives, compressed air, or hydraulic pressure. The only means for conveying the missile is due to the pressure difierence between the atmospheric pressure and a vacuum Within the gun barrel.

The majority of guns in existence today propel a missile by means of the pressure derived from an exploding mass. All these guns have the disadvantage of producing a recoil and considerable heat and incandescent gas. Some guns have been made which use compressed gas as the propellant. These guns also produce a recoil and require a heavy gun barrel which is able to withstand the pressure of the compressed gas.

The present invention operates entirely by means of atmospheric pressure and for this reason there is no recoil to the gun, there is no heat generated in the gun or in the missile and there is no flash or danger of fire anywhere within the vicinity of the gun. The only recoil which is possible with this type of gun is the slight frictional drag produced by the missile as it travels through the barrel and this force is exerted in the same direction the missile takes instead of the opposite direction. In explosive type guns the force generated by the explosive chemical exerts a maximum force shortly after it has been exploded, then the pressure diminishes as the projectile travels through the barrel and is almost Zero as the missile leaves the barrel. In the vacuum type gun the pressure is constant throughout the entire travel of the missile through the length of the barrel.

One of the objects of this invention is to provide an improved gun which avoids one or more of the disadvantages and limitations of prior art guns.

Another object of the invention is to throw a heavy projectile a distance from the gun at a reduced cost as compared to other types of guns now in use.

Another object of the invention is to increase the safety of guns by reducing the danger of explosion, the danger of fire, and the danger of exploding the barrel.

Another object of the invention is to provide a gun having substantially no recoil.

Another object of the invention is to provide a gun which gives constant maximum acceleration to a missile throughout the entire length of the gun barrel.

Another object of the invention is to provide a gun which is essentially noiseless and produces no visible flash.

Another object of the invention is to reduce the heat expended during the projection of the missile.

The invention comprises a vacuum gun for projecting a missile a considerable distance from the gun and includes a hollow cylindrical barrel having a removable closure means at one end and an opening at the other end for inserting a missile. The missile is held by a releasable means at one end of the barrel and a vacuum pump is 3,039,450 Patented June 19, 1962 provided for removing the air from the barrel prior to firing.

For a better understanding of the present invention, together with other and further objects thereof, reference is made to the following description taken in connection with the accompanying drawings.

FIG. 1 is a side view of the gun showing its mounting and a vacuum pump connected to the barrel.

FIG. 2 is a cross sectional view of the barrel shown in FIG. 1.

FIG. 3 is a cross sectional view of the barrel shown in FIG. 1 and is taken along line 3-3 of that figure.

FIG. 4 is a cross sectional view showing an alternate closure means for the barrel.

FIG. 5 is an end view of the closure means shown in FIG. 4.

FIG. 6 is a cross sectional view of a portion of the closure means shown in FIGS. 4 and 5.

FIG. 7 is still another alternate means for closing one end of the barrel.

FIG. 8 is a sectional view of a means of closing the end of the gin and a system which removes the end prior to the arrival of the missile.

FIG. 9 is an end view (with a portion in section) of the gun shown in FIG. 8.

FIG. 10 is a sectional view of an alternate means for releasing the end cover just before the missile arrives at the tube end.

FIG. 11 is a cross sectional view of the barrel shown in FIG. 10 and is taken along the line 1111 of that figure.

Referring now to FIGS. 1, 2, and 3, the gun comprises a hollow cylindrical tube 10 which is closed at one end with a cap 11 and includes a missile 12 inserted in the other end. The gun is mounted by means of two stub shafts 13 and 14 which are journaled in upright supports 15 and 16 set on a base 17. The missile 12 is made with an eye or hook 18 so that it may be releasably secured by means of a string 20 secured to a bracket 21 which is fastened to a portion of the barrel. FIG. 1 shows a string 20 which retains the missile 12, this string being designed to be clipped by a cutting tool when the missile is to be propelled through the gun barrel. It is understood that other forms of releasable mechanisms may be used and a missile launched by a trigger mechanism which releases the missile.

In order to operate the gun, a vacuum must be pumped to remove the air from the interior of the barrel. The easiest way to do this is by a mechanical vacuum pump 22 connected to the barrel by a flexible conduit 23 and run by means of a belt 24 coupled to an electric motor 25. However, the vacuum pump 22 may be turned by hand and other simpler forms of vacuum apparatus may be used. One of these is a liquid aspirator which removes air from an enclosure by means of a stream of water or other liquid passing through an orifice. It is obvious that the vacuum within the barrel does not have to be entirely free of air. It has been found by experiment that pressures of a few millimeters of mercury produce substantially the same throwing power as pressures which proximate one or two microns.

FIG. 2 shows the details of the closure means 11 which includes an 0 ring 27 which seals one end against air leakage and the missile 12 which contains a charge 28 3 and two rings 30 and 31 for sealing the barrel while it is being pumped and during the passage of the missile through the barrel.

The cross sectional drawing of FIG. 3 indicates one way in which the barrel It} may be mounted to facilitate rotation about a horizontal axis. It will be obvious that many other forms of mounting can be used and since there is no recoil, the barrel may be held in the arms without benefit of any other mechanical support. It should be pointed out here that the barrel may be made quite light, of thin aluminum material since it is only required to withstand the pressure of the atmosphere which is less than pounds per square inch.

The closure means shown in FIGS. 1 and 2 comprise a wooden or plastic cap which fits into one end of the barrel and which is blown out by the inertia of the missile when the gun is fired. Other forms of closure means may be used, an alternate form being shown in FIGS. 4, 5', land 6, where a four element conical cap 33 is placed over the end of the barrel. The conical cap may be divided into four segments 34, 3'5, 36, and 37, and is retained on the barrel rim by an annular resilient ring 38 of plastic or rubber. Leakage is prevented by means of an 0 ring 40 and the four segments are coupled together by means of a rubber or plastic insert il shown in detail in FIG. 6. This conical closure is designated to open like a gate when the missile 12 is propelled through th barrel. Other closure means may be provided for hinging the four components to the end of the barrel so that they will always be available after firing to close the end of the barrel in preparation for a second vacuum pumping and another firing.

The cross sectional view shown in FIG. 7 shows a second alternate means for closing the end of the barrel. This closure means includes a thick plastic sheet 43 placed over the open end of the barrel and retained in position by a clamp 44 which may be a metallic clamp or a flexible plastic ring which secures the periphery of the plastic disk to the outside surface of the barrel. When this closure means is employed, the missile 12 may either puncture the diaphragm 43 or the entire structure may be removed from the end of the barrel and carried with the missile to its destination.

The operation of the gun is obvious. The cap 11 is placed on one end and the missile 12 is inserted into the other end with a releasable means holding it in place. Then the inner space is exhausted by means of a pump and when the pressure is reasonably low the string 26 is cut and the missile is propelled along the barrel by atmospheric pressure. With reasonably long barrels the velocity of the missile should increase uniformly as it traverses the length of the barrel because the atmospheric pressure behind it is constant. On reaching the end of the barrel the cap 11 is removed from the barrel due to the inertia of the missile and either falls to the ground or is carried along with the missile.

It will be obvious that the pressures exerted on the exterior of the barrel never exceed atmospheric pressure, therefore the bar-rel may be made of light material, even plastic. It is also evident that there is no flash, no danger of starting a fire, and no recoil. One of the applications of this vacuum gun is the throwing of large barrels of water into a forest fire from considerable distances. In this type of application the gain has the advantage of low weight, absence of fire hazard, and considerable maneuverability in forest areas.

The gun shown in FIGS. 8 and 9 includes the usual barrel it and detachable cover 11. In addition, a reentrant pipe 50 is joined to the barrel at a point 51 intermediate between the barrel ends. The other end or" the pipe is also joined to the barrel at a point 52 close to the cover 11. A valve 53 is connected between the two ends to regulate the flow of air through the pipe.

This device operates as follows: When the missile is released, it travels along the barrel propelled by atmospheric pressure. After it passes point 51, air passes into the tube, through the valve 53, and into the space between the missile and the cover 11. This air is compressed by the missile and blows the cover off the end of the barrel, insuring that the missile shall have a free, unimpeded trajectory.

The gun cover shown in FIGS. 10 and 11 is still another device for removing the end cover just before the missile arrives at the end of the barrel. The barrel 10 is provided with a hinged cover 54, pivoted on a pin 55, secured to a bracket 56 which is secured to the side of the barrel 10. Cover 54 is engaged by three springs 57, 58, and 60 (see also FIG. 11) which press against the barrel side of the cover and are strong enough to open the cover even while it is held in its closed position by atmospheric pressure. While the barrel is being evacuated of air the cover 54 is held in place by a latch 61, pivoted at 62, and including a piston 63 which fits into a small chamber 64. The chamber 64 is connected by a pipe 65 to an opening 66 which is intermediate the two ends of the barrel. Latch 61 is urged to an unlatch position by a compression spring 67 but this spring is chosen to permit the latch to remain in its latched position when the barrel is evacuated and the piston 63 held in chamber 64 by atmospheric presure.

When the missile is released, it travels along the barrel, followed by atmospheric pressure and, when the missile passes opening 66, atmospheric pressure is admitted to pipe 65 and piston 63 is released. Spring 67 removes latch 61 from cover 54 and springs 57, 58, and 60 force the cover open just before the arrival of the missile. in this manner the missile is allowed to move into its natural trajectory without the hindrance of the cover or any of its components.

While there have been described and illustrated specific embodiments of the invention, it will be obvious that various changes and modifications can be made in the barrel and in the vacuum pump without departing from the field of the invention which should be limited only by the scope of the appended claims.

I claim:

1. A vacuum gun for projecting a missile comprising, a hollow cylindrical barrel having a removable closure means at one end and an opening at the other end for inserting the missile, releasable means for restraining the missile at one end of the barrel, and means for removing the air from the barrel to create a partial vacuum therein prior to projecting the missile.

2. A vacuum gun for projecting a missile comprising, a straight hollow cylindrical barrel having a removable closure means at one end and an opening at the other end for inserting the missile, releasable means for restraining the missile at one end of the barrel, and a vacuum pump for removing air from the barrel to create a partial vacuum therein prior to projecting the missile.

3. A vacuum gun for projecting a missile comprising, a straight hollow cylindrical barrel having a removable air-tight closure means at one end and an opening at the other end for inserting the missile, releasable means for restraining the missile at said other end of the barrel, a vacuum pump for removing air from the barrel to create a partial vacuum therein prior to projecting the missile, and a flexible conduit connected between the barrel and the vacuum pump.

4. A vacuum gun as set forth in claim 3 in combination with a missile which is formed with a plurality of encircling deformable rings for sealing the interior of the barrel against air leakage.

5. A vacuum gun as set forth in claim 3 wherein the closure means is sealed against leakage by means of a deformable ring positioned in a slot in the closure body and making contact with the inside surface of the barrel.

6. A vacuum gun as set forth in claim 3 wherein said closure means is resiliently secured to the end of the barrel by a resilient band.

7. A vacuum gun for projecting a missile comprising,

References Cited in the file of this patent UNITED STATES PATENTS Bostedo et a1. Sept. 4, Dinspel Mar. 31, Blurne July 18, Amdur Oct. 22, Halpern June 14, Kjellsen July 15,

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