US3495580A

US3495580A - Air gun

Info

Publication number: US3495580A
Application number: US663452A
Authority: US
Inventors: Baltzar Leo De Mare
Original assignee: US Department of Army
Current assignee: US Department of Army
Priority date: 1967-08-25
Filing date: 1967-08-25
Publication date: 1970-02-17
Anticipated expiration: 1987-02-17

Description

Feb. 17, 1970 AIR GUN 2 sheets-sheet 1 Filed Aug. 25, 196'? INVENTOR Fb. 17, 19170 j B. L. DE MARE/ 'AIR GUN I F11-ed Aug. 25, 19s? 2- sheets-'sheetl 2 INVENTOR azyf e0 mare United States Patent O 3,495,580 AIR GUN Baltzar Leo De Mar, Aberdeen, Md., assignor to the United States of America as represented by the Secretary of the Army y Filed Aug. 25, 1967, Ser. No. 663,452 Int. Cl. F41b 11 00; F41c 19/00; F41d 11/00 U.S. Cl. 124--11 8 Claims ABSTRACT F THE DISCLOSURE n struck by a spring loaded plunger which is held in place by a remote controlled sear.

The invention described herein may be manufactured,

used, and licensed by or for the Government for governmental purposes without the payment to me of any royalty thereon.

Air guns are often used to facilitate studies of the ilight and impact characteristics of small projectiles, i.e. 22 to 60 caliber, at muzzle velocities of from 150 to 800 feet per second.

Compressed air (or any equivalent gas) used in this type gun, as well as in a number of types of shoulder and handguns has a number of advantages as follows:

(a) It is much easier to control the velocity as to magnitude and repeatability with compressed air than with an explosive charge.

(b) Air (or equivalent gas) is clean and safe and does not foul the bore of the gun tube.

(c) It does not erode the gun tube.

(d) No special propellant storage facilities are required, as in the case of explosive charges.

(e) Air guns are relatively quiet in operation, a desirable feature when firing in indoor ranges adjacent to oices and in laboratories.

While the gun of the present invention will be hereinafter described as an air gun, it is desired to use nitrogen gas as a propellant since it Will not form an explosive mixture in the presence of oil or grease which may be present in the mechanism. Nitrogen, also, will not promote corrosion. This gas may be supplied to the valve mechanism from a tank with an initial pressure of approximately 2300 p.s.i.

It is therefore an object of this invention to provide an air gun for testing the ight and impact characteristics that is compact and easy of operation.

Another object is to provide an air gun having a balanced piston valve upon which a gas will act with equal force in opposite directions and ywill move to iire the gun only upon application of an external force thereon.

A further object is to provide an air gunin which the operating elements are easily mounted or" dismounted for replacement thereof.

These and other objects and advantages ofthe present invention will be fully apparent from the following description when taken in connection with the annexed drawings, in which:

FIG. l is a side elevation, partly in section, of the assembled air gun of the present invention, the tiring mechanism being in cocked position;

FIG. 2 is an enlarged view of the sear mechanism;

FIG. 3 is a cross section view taken along line 3-3 of FIG. l and looking in the direction of the arrows;

FIG. 4 is an enlarged side elevation view of a modified form of valve;

FIG. 5 is an enlarged detail section of a further modification of a valve for use when using a uid as the propellant, and

FIG. 6 is a still further modified valve for the same use.

Referring in detail to the drawings in which life reference numerals denote like parts throughout, reference character 1 designates generally the air gun of this invention and comprises a charging valve mechanism, generally indicated by 2, a spring actuated tiring mechanism, generally indicated by 3, a gun barrel attachment generally indicated by 4, a base upon which the aforesaid mechanisms are mounted, generally indicated by 5, and

an air supplying system (FIG. 3) generally indicated by 6.

CHARGING VALVE MECHANISM The charging valve mechanism 2 consists of a housing 7 having 'a longitudinal ibore 8 which is flared at its forward end as at 9 to a larger diameter 10, as seen in FIG. l.

An :end closure 11 having an axial bore 12 is threadably engaged in the rearward end of bore 8, as shown.

An air admission port 13 is disposed normal to bore 8 in housing 7, as shown in FIG. l.

A double-ended piston valve, generally indicated by 14 is slidable in bore 8. This valve comprises a stem 15 which extends rearwardly through bore 11, as shown, and a block 16 is threadably engaged 0n its rearward end.

Block 16 is notched at its upper surface as at 17 to provide means for the engagement of a safety latch 18 which is pivotally mounted as at 19 to a rod 20 threaded into housing 7.

A tooth 21 on the bottom of latch 18 normally engages in notch 17 and prevents forward movement of valve 14 in bore 8.

Latch 18 is biased downwardly by a spring 22, and is provided with a shoulder 23 normally engaging the rearward end of block 16.

Means to provide retraction of valve 14 are provided and consists of a clock spring 24 normally wound on a drum 25 and attached at its end to a yoke 26 iixed to the lower end of block 16 as shown.

The valve 14 is provided with a rst piston 27 at is forward end and is provided with an annular groove 28 which receives an O-ring 29 therein.

A skirt 30 having ports 31 is also provided on the forward piston 27 as seen in FIG. l and slidably supports valve 14 and axial position when piston 27 moves into larger diameter 10.

A second piston 32 is provided on the rearward portion of stem 15 and has annular groove 33 and which receive an O-ring 34 therein. The forward end of housing 7 is provided with an annular ange 35 for a purpose to be described later.

SPRING ACTUATED FIRING MECHANISM Spring actuated iiring mechanism 3 comprises a mounting block 36 having a longitudinal bore 37 in which a tubular housing 38 is mounted.

Tubular housing 38 is closed at its forward endand this end is axially bored as at 39. A cap 40 having an axial bore is threadably engaged on the open end of housing 38.

A ring plunger 42 is slidable in bores 39 and 41 and extends beyond housing 38 at both of its ends, as shown.

The rearward end of plunger 42 terminates in a cooking lug 42a having an annular groove 43 which is provided With a beveled forward wall 44. Lug 42a is also beveled at its rearward end as at 45.

The forward end of 42 is urged in a forward direction by a coil spring 93 encircling plunger 42 in housing 38 biases between cap 40 and a disc 94 which is carried by plunger 42 and slides in tubular housing 38.

A sear mounting block 46 is spaced rearwardly from block 36 and is bifurcated at its upper portion to provide a pair of upstanding ears 47 between which a sear 48 is pivoted as at 49 (FIG. 2).

Sear 48 is biased upwardly by a coil spring 50 in block 46, so that when the firing mechanism is cocked, it will engage in annular groove 43.

Sear 48 is further provided with a stud 51 which is normal to its side and bears against one leg of a bell crank 52 which is also pivoted between ears 47 as at 53. The other leg of bell crank 52 is pivoted to a trigger rod 54 as at 55.

Rod 54 is slidable in a bearing block 56 which is provided with a safety screw 57 when it is desired to lock rod 54 against axial movement therein.

A block 58 is threadably mounted on the free end of trigger rod 54 and is transversely bored at its end as at 59 to receive a ring 60 to which a lanyard 61 may be attached. Block 58 also provides a stop which will bear against block 56 to limit forward movement of rod 54 therein.

A handle 62 is pivoted at 63 as shown and a pair of links 64 (one being shown) are pivoted at 65 to a block 65a Which is slidable on ring plunger 42 and to handle 62 as at 66, providing a means of cocking the firing mechanism 3.

Handle 62 is normally rotated in a counter clockwise manner by bias of a torsion spring 67 when not in use, and block 65a -Will act as a stop for limiting forward movement of plunger 42 and handle 62.

GUN BARREL ATTACHMENT The gun barrel attachment 4 is for the purpose of slidably supporting a gun barrel 68 and for its connection to housing 7.

A clamp 69 (one or more similar clamps will be employed throughout its length) encircles barrel 68 and is secured thereon by bolts 70.

Short barrels will require two clamps, but the number will vary as desired depending on the length of barrel.

Clamps 69 are bored as at 71 on their lower portions (only one side of the clamp being shown) and bores 71 receive a rod 72 therethrough (two rods are required).

Rods 72 are supported in mounting blocks 73, only one block shown (there will be a block at each end of each rod for their support).

Gun barrel 68, when connected to housing 7, fits over a portion of housing 7 to bear against ilange 35.

A threaded collar 74 slidable on housing 7 is screwed over a threaded portion 68a on gun barrel 68 when it is desired to attach the barrel 68 to housing 7.

When the collar 74 is tightened it pulls the gun barrel 68 rearwardly against the flange 35, and the bore 75 of the gun barrel 68 will be in axial alignment with bore of larger diameter in housing 7 as seen in FIG. 1.

BASE

The base 5 will be best seen in FIG. 3, and comprises a plate 76 to which the valve mechanism 2, firing mechanism 3 and gun lbarrel attachment 4 are mounted by screws, welding, etc., in longitudinal arrangement, so that the gun barrel bore 75, bore 8 in valve housing 7 and ring plunger 42 are in axial alignment as seen in FIG. 1.

Plate 76 is mounted to a slide 77 which has a runner 78 on each side so that it may be mounted in ways 79 (Shown in broken lines) of a gun mount, not shown.

4 AIR SUPPLY SYSTEM The air supply system 6 is shown in FIG. 3 and consists of an angle strip 80 mounted transversely on housing 7 and provides supporting means for an air supply line 81 which may be connected to a compressed air (or gas) tank, not shown.

Air line 81 leads into port 13 in housing 7. A charging valve 82 in air line 81 provides means for admitting or shutting off the air supply to bore 8 in housing 7.

An air exhaust line leading from bore 8 in housing 7 to the atmosphere provides air escape therefrom.

A pressure gage 83 and a relief valve 84 are connected to line 85 completing the air supply system.

Gage 83 and valves 82 and 84 are also supported by angle strip 80.

In FIG. 4, there is illustrated a modied valve in which the skirt 30 is dispensed with and a spider 86 substituted therefor.

Further modied valves are shown in FIGS. 5 and 6. Their construction is identical, only the dimensions are changed.

Each valve has a forward piston head 96 instead of the O-ring in piston 27. The heads have a beveled edge 87 which seats in a conical valve seat 88 formed in an insert xed in housing 7.

In these forms, bore 8 is also changed in diameter.

Bore 8 is counterbored as at 90 at its forward end to provide a larger bore than 8 whereby the rearward piston 32 is of smaller diameter than head 86.

In FIG. 6, the bore 8 is the inverse of that shown in FIG. 5, bore 90a being smaller than bore 8, so that the rearward piston 32 is larger in diameter than the head 96.

In both forms shown in FIGS. 5 and 6, the valve stem 15 is provided with a head 91 at its rearward end and a light coil spring 92 encircling stem 15 replaces clock spring 24 (see FIG. 5).

Both modified forms use the piston head 96 in lieu of the O-ring 29 which is likely to be washed off by outflowing fluid under high pressure.

In the case of the valve of FIG. 5 wherein the forward piston head is larger than the rearward piston 32, there will be a.relatively slight opening force, but this force is overcome by light spring 92.

In the case of the valve of FIG. 6 wherein the rearward piston 32 is larger than the forward piston 86, the higher the contained pressure, the greater is the sealing pressure of the forward piston 96.

In both modified forms, a comparatively low external force is sufficient to open the valve. When the fluid is discharged from the valve housing, the spring 92 will return the valve to its closed position.

If desired, the gun may be fired electrically by mounting a solenoid (not shown) on base 5, which will be attached to trigger rod 54 in lieu of lanyard 61.

OPERATION Operation of the air gun is simple. The barrel 68 is first loaded. To load the gun barrel 68, collar 74 is unscrewed and barrel 68 is moved forwardly on rods 72. After loading the barrel 68 is moved rearwardly until it abuts llange 35, and collar 74 is screwed over threaded portion 68a and tightened.

The tiring mechanism 3 is then cocked by rotating handle 62 clockwise whereby block 65a, sliding on plunger 42 abuts lug 42a and retracts the plunger 42. Upon rearward movement, bevel 45 on lug 42a rides over sear 48 until it falls into groove 43.

A charge of pressurized air (or nitrogen) from a tank, not shown, is then admitted to bore 8 in housing 7 by opening charging valve 82 until the desired pressure is read on gage 83.

Then the valve 82 is closed.

Since the piston valve 14 is balanced and is held in its closed position by clock spring 24, it has no tendency to open under pressure as air pressure in bore 8 will act with equal force in opposite directions.

To fire the gun, lanyard 61 is pulled which disengages sear 48 by bell crank 52 which pivots downwardly on stud 51, causing the firing plunger 42 to be moved forward by spring 93 bearing against disc 94 on plunger 42.

The forward end of plunger 42 in moving forward rides under a beveled edge 95 of latch 18 and lifts it upwardly. The plunger 42 then strikes block 16 which, in turn, moves forward to slide valve rod 15 and pistons 27 and 32 forwardly to open position where piston 27 enters enlarged diameter 10 in bore 8.

The charge of pressurized air in bore 8 rushes through ports 31 in skirt 30 and into the breech of the gun barrel to propel a projectile down the barrel 68.

Spring 24 will now act to retract valve 14 to its closed position.

Air can be exhausted from housing 7 when desired by opening relief valve 84 in case of malfunction of the gun, etc.

While only prefered forms of the invention are shown and described, other forms of the invention are conemplated and numerous changes and modifications may be made thereon without departing from the spirit of the invention as set forth in the appended claims.

What is claimed is:

1. An air gun comprising in combination, a base, a valve housing having a longitudinal bore therethrough mounted on said base, said bore flaring outwardly at its forward portion to a larger diameter, there being an airport in said valve housing and communicating with said longitudinal bore, a closure having an axial bore mounted in the rearward end of said longitudinal bore, a valve stem slidable in said axial bore and extending a substantial distance rearwardly thereof, a first piston carried by the forward end of said stem and slidable in said longitudinal bore forwardly .of said airport, a second piston carried by the rearward portion of said stem and slidable in said longitudinal bore rearwardly of said airport, means carried by the forward portion of said stem for axially supporting said first piston when moved into said larger diameter ,of said longitudinal bore, spring means connected to the rearward end of said valve stem for urging said stem in a retracted position whereby the forward end of said longitudinal bore is sealed by said l'irst piston, a gun barrel slidably mounted on said base and being adaptable for detachable connection at its breech to the forward end of said valve housing, a firing mechanism for activating said valve stem and pistons mounted rearwardly of said valve housing on said base, an air supply system connected to said valve housing adapted to supply pressurized air to said valve housing whereby when said valve stern and pistons are activated by said firing mechanism a burst of air is admitted to said `gun barrel to propel a projectile when therein and means mounted on the rearward portion .of said valve housing to normally restrain said valve stern in a rearward position in said longitudinal bore until released by said firing mechanism.

2. An air gun as claimed in claim 1, wherein said means for supporting said first piston in said longitudinal bore comprises a tubular skirt fixed to the rearward end of said first piston and slidable therewith in said longitudinal bore, there being a series ,of circumferentially arranged ports therein.

3. An air gun as claimed in claim 1, wherein said means for supporting said first piston in said longitudinal bore comprises a spider carried by said valve stern and disposed adjacent the rearward end of said first piston and slidable therewith in said last named bore.

4. An air gun as claimed in claim 1, whe-rein said first and second pistons comprise a piston head having a di ameter slightly less than the diameter of said longitudinal bore, there being an annular groove in the circumferential surface of said heads and an O-ring in said groove of each head whereby said longitudinal bore is normally sealed on each side of said air port.

5. An air gun as claimed in claim 1, wherein said first piston comprises a piston head having a beveled inner edge, there being a conical valve seat in said housing to provide a valve seat for said inner edge when said mechanism is in closed position.

6. An air gun as claimed in claim 1, wherein the forward portion of said longitudinal bore is counterbored to provide a larger diameter than the rearward portion and said first piston is correspondingly enlarged whereby said rst piston has a larger sealing diameter than said second piston.

7. An air gun as claimed in claim 1, wherein the rearward portion of said longitudinal bore is counterbored to Iprovide a larger diameter than the forward portion and said second piston is correspondingly enlarged whereby said second piston has a larger sealing diameter than Said first piston.

8. An air gun as claimed in claim 1, wherein said firing mechanism comprises a tubular housing supported on said base rearwardly of said valve housing, a spring biased ring plunger having a cocking lug at its rearward end, a sear mounting block mounted on said base rearwardly of said tubular housing, a spring loaded sear rotatably mounted in said block and adapted to engage said cocking lug when said tiring plunger is in a cocked position, a spring biased cocking lever piVota-lly mounted `on said base rearwardly of said sear block, a block slidable on said ring plunger between said tubular housing and said cocking lug, a pair of links connecting said block on said plunger to said handle whereby when said handle is rotated clockwise, said block on said plunger will engage said cocking lug to move said plunger rearwardly and permit said sear to engage said scar lug thereon and hold said plunger in said cocked position, a bell crank rotatably mounted on said sear mounting block and engaging said Sear, and a trigger rod mounted on said base and connected at its forward end to said bell crank whereby when said trigger rod is pulled rearwardly said bell crank will rotate said sear out of said cocking lug to permit said plunger to move forwardly to activate said valve stem and pistons.

References Cited UNITED STATES PATENTS 2,304,841 12/ 1942 Mikkelsen 124-11 2,574,408 11/1951 Moc 124-11 3,088,225 5/ 1963 Amistadi 124-11 3,254,640 6/1966 Sprouse 124-37 3,308,803 3/1967 Walther 124-37 FOREIGN PATENTS 1,108,641 1/1956 France.

519,143 3/1955 Italy.

711,542 7/ 1954 Great Britain.

RICHARD C. PINKHAM, Primary Examiner RICHARD W. DIAZ, Assistant lExaminer U.S. Cl. X.R. 124-34