US3855989A

US3855989A - Pump-type air gun with tubular valve member

Info

Publication number: US3855989A
Application number: US00316702A
Authority: US
Inventors: D Hand
Original assignee: CROSSMAN ARMS CO Inc
Current assignee: FIRST SOURCE FINANCIAL LLP; Tokyo Electron Ltd; Crosman Corp
Priority date: 1972-12-20
Filing date: 1972-12-20
Publication date: 1974-12-24
Anticipated expiration: 1991-12-24

Abstract

A pump-type air gun in which the pump cylinder is connected directly to a pressure chamber closed by a tubular valve member that is released on operation of the trigger to supply compressed air from the chamber directly behind a BB that registers with the gun barrel. BBs are fed into firing position from a magazine by a spring pressed follower. The ratio of the volume of the pump cylinder to the volume of the pressure chamber, when the pump piston is in withdrawn position, that is, when the pump cylinder is at atmospheric pressure, is such that only one stroke of the pump lever is required to fill the pressure chamber with air under a pressure sufficient to fire a BB from the gun.

Description

United States Patent [191 Hand 1 Dec. 24, 1974 I v 22 Filed:

[ 1 PUMP-TYPE AIR GUN WITH TUBULAR VALVE MEMBER [75] Inventor: David R. Hand, Rochester, N.Y.

[73] Assignee: Crossman Arms Company, Inc., Fairport, N.Y.

Dec. 20, 1972 [21] Appl. No.: 316,702

[52] 11.8. C1 124/13 A [51] Int. Cl ..F41b 11/00 [58] Field 01 Search 124/11 R, 13 A, 15

[56] References Cited UNITED STATES PATENTS 2,119,441 5/1938 Price 124/13 A 2,537,358 1/1951 Lincoln 124/11 R 2,881,752 4/1959 Blahnik 124/11 R 3,199,501 8/1965 Bertschinger 12.4/11 R 3,212,489 10/1965 Merz 124/11 R 3,212,490 10/1965 Merz,. 124/15 Primary Examiner-Richard C. Pinkham Assistant Examiner-R. T. Stouffer Attorney, Agent, or Firm-Shlesinger, Fitzsimmons. & Shlesinger [5 7] I ABSTRACT A pump-type air gun in which the pump cylinder is connected directly to a pressure chamber closed by a tubular-valve member that is released on operation of the trigger to supply compressed air from the chamber directly behind a BB that registers with the gun barrel. BBs are fed into firing position from a magazine by a spring pressed follower. The ratio of the volume of the pump cylinder to the volume of the pressure chamber, when the pump piston is in withdrawn position, that is, when the pump cylinder is at atmospheric pressure, is such that only one stroke of the pump lever is required to fill the pressure chamber with air under a pressure sufficient to fire a BB from the gun.

10 Claims, 5 Drawing Figures PATENTED DEC24 I974 saw a or 2 PUMP-TYPE AIR GUN WITH TUBULAR VALVE MEMBER This invention relates to air guns, and more particularly to a pump-type carbine for shooting BB shots.

With prior pump-type air guns it has been necessary to pump a manually-operated piston several times in order to compress the air sufficiently to fire a BB projectile from the gun. This is bothersome and reduces the speed at which the gun can be fired.

In the past, moreover, pump-type BB guns have tended to be rather complex in construction and expensive to manufacture. Numerous moving parts have been required to feed BBs from the magazine of the gun into firing position, and to control the flow of compressed air from the pressure chamber to the rear of a projectile in firing position. Typically the flow of compressed air is controlled by a spring-loaded valve, which is opened momentarily by the hammer upon operation of the trigger.

A primary object of this invention is to provide a BB gun, which requires that the pump lever be actuated only once to compress the air to the pressure needed to propel a BB from the gun.

Another object of this invention is to provide a more compact pump-type BB carbine, which has substantially fewer moving parts than prior such carbines.

Another object of the invention is to provide a pump gun of the type described, which has a hammerless valve mechanism for controlling admission of compressed air to the firing chamber of the gun.

Other objects of the invention will be apparent hereinafter from the specification and from the recital of the appended claims, particularly when read in conjunction with the accompanying drawings.

In the drawings:

FIGS. 1A and 1B, taken together, comprise a fragmentary side elevation view of a pump-type BB carbine made according to one embodiment of this invention, portions of the carbine being cut away and shown in section;

FIG. 2 is a fragmentary plan view of this carbine portions thereof again broken away and shown in section;

FIG. 3 is an enlarged, fragmentary sectional view of this carbine taken along line 33 in FIG. 1A looking in the direction of the arrows; and

FIG. 4 is a fragmentary sectional view taken along the line 44 in FIG. 1A looking in the direction of the arrows.

Referring now to the drawings by numerals of reference, denotes generally the gun frame, to the rear side of which there is attached a conventional gun stock 12. Secured in the forward end 13 of frame 10 is an elongate barrel housing 14 (FIGS. 1 to 3). Housing 14 contains a tubular gun barrel 15, which projects at its rear end into a bore 16 in a block 17 that is mounted in the frame.

Threaded in the front end 13 of frame 10, and supported by a bracket 21 beneath the barrel housing 14 is an elongate sleeve 20, the outer end of which is closed by a plug 22. Sleeve registers with the axial bore of a cylinder 23, which is secured in block 17 with its forward end surrounding the rear end of sleeve 20 coaxially thereof.

A valve block 25, which is fastened by a screw 26 in the frame 10 rearwardlyof block 17, has on its forward end a cylindrical boss 27, which projects coaxially into the rear end of cylinder 23'for a slight distance and helps support the cylinder. An O-ring 28, which is seated in an annular recess in the periphery of the bos 27, seals the rear end of cylinder 23. I

A piston 30 (F1G. l) is reciprocable in cylinder 23. It carries in grooves in its periphery, the usual packing ring 31 and resilient O-ring 32 for compressing air between the piston and boss 27'.' Projecting forwardly from piston is a piston rod 34, which extends coaxially through cylinder 23 into the rear end of sleeve 20. Secured to the forward end of rod 34 for reciprocation therewith in sleeve 20 is a cylindrical guide block 35.

Reciprocable motion is imparted to piston 30, its rod 34 and guide block 35 by a pivoted operating lever 36 (FIG. 1), which has a web section 37 that projects up wardly through a slot 38 in the underside of sleeve 20. At its forward end web section 37 is pivoted on a pin 40, which is fastened in sleeve 20. Intermediate its ends the web section 37 carries a pin 42, which is pivotally connected to one end of a pair of links 44. These two links, which register with the slot 38 in the underside of sleeve 20, are pivotally connected at their rear ends by a pin to the projection 46 formed on the forward end of guide block 35. I

In its upper portion'valve block 25 has a pressure chamber 50 (FIG. 1), which "is closed at its rear end by a plug 51, and which is connected intermediate its ends via a right angular duct 52 in block 25 with the rearend of cylinder 23. A port 53 in the forward end of chamber 50 registers with a stud 55 on plug 51, and a port 57 in block '17. v

Mounted to reciprocate in the

blocks

17 and 25, and projecting at opposite ends slidably and coaxially into the

aligned ports

57 and 53 in these two blocks is an. elongate, tubular valve member 60 (FIGS. 1 to3). In- 7 termediate its ends valve member 60 has an enlarged, external, circumferential flange 61, which seats against plane surface 54 on the front end of valve block 25, when the gun is in cocked position. Also at this time the rear end of the valve member engages over the forwardly-projecting stem 55 of plug 51 but, as denoted at 63 (FIG. 1), witha slight space between the plug and the rear end of the valve member. The stud 55 fits snugly in valve member 60.

Mounted. for limited swinging movement on cylinder 23 is a yoke 65 whose legs 66 are pivotally mounted interrnediate their ends on aligned pins 67 in block 25. The upper, free ends 68 of legs 66 are bent laterally inwardly in front of flange 61. The lower end 69 of the yoke extends .transversely beneath cylinder 23.

Mounted beneath the yoke 65 to pivot of frame 10 is a trigger 74. When the trigger is cocked a scar on the trigger is engaged-with the lower end 69 of the yoke 65 to prevent the yoke from pivoting clockwise (FIG.

1) about the axis of pins 67.

Mounted to reciprocate parallel to and beneath the cylinder 23, and to one side of trigger 74 (FIG. 3), is

lower end 69 of yoke 65, and forwardly of trigger pivot pin 71-. The forward portion of rod 80 is surrounded by a coiled spring 87 (FIG. 1), one end of which seats against an external shoulder 88 on the rod and the opposite end of which seats against rib 82. Spring 87 normally urges rod 80 rearwardly in frame 10, so that its rear end 86 seats against trigger pivot pin 71.

Secured in a longitudinally extending groove 91 formed in one side of barrel housing 14, and extending through the front of the frame in side-by-side, parallel relation to barrel 15, is a tubular magazine 92. Mounted to reciprocate in magazine 92 in conventional fashion is a follower rod 94 having adjacent its outer end a radial pin 95 (FIG. 2), which slides in an elongate slot 96 in the magazine. Rod 94 is constantly urged rearwardly in the magazine by a spring 97, which is disposed between the outer end of rod 94 and a plug 98,

which is fastened in the outer end of the magazine. The

inner end of magazine 92 projects into the block 17 alongside barrel 15, and registers with a transfer port 99 in the block 17, which connects the inner end of the magazine with bore 57 immediately behind barrel 15. A leaf spring 100 is secured in rod 94 at one end by a right angular leg 101. This spring has a slightly curved free end 102, which registers with a shallow recess notch 104 in the rear end of rod 94.

To load the magazine, rod 94 is pushed forward manually by pin 95 against the resistance of spring 97 until the rear end of the rod is forward of a circular loading aperture 106 (FIG. 2), in the magazine; and 885 are inserted into the magazine. Upon release of rod 94 the BBs will be pushed rearwardly by the rod, and the rearmost BB will be pushed into port '99. An inclined face 110 formed in block 17 at the rear of port 99 guides this rearmost BB laterally through port 99 into the space between valve member 57 andthe rear end of barrel 15. The BB is held in firing position behind the 50 is sufficient to propel-a BB 108 out of the barrel 15 with adequate muzzle velocity.

During compression of air into chamber 50, sear 75 maintains the yoke 65 in a blocking position in which the upper ends 68 of its legs 66 hold valve member 60 seated on the stud 55. However, when the gun is fired by pressing on trigger 74, the sear 75 drops down from engagement with the yoke. The compressed air in chamber 50, acting in the space 63 between the rear end of valve member 60 and plug 51, moves the nowreleased valve member suddenly forwardly, so that its forward end forces the BB 108 into the rear of barrel 15. At the same time, the rear end of the valve member 60 is advanced off stud 55, so that by the time the BB 108 has been shoved into the barrel, the rear end of the valve member will have advanced far enough for the compressed air in chamber 50 to pass through the axial bore in the valve to the rear of the BB 108, thereby propelling the latter out of the barrel with the full volume and force of the compressed air. During this advance flange 61 of the valve member urges the upper end .of yoke 65 forwardly, so that the yoke is pivoted slightly forwardly or clockwise (FIG. 1) about the axis of pins 67. After the gun has been fired piston is at the rear of cylinder 23 (FIG. 1), and the spring 87 will have returned rod 80 to its normal position in which its rear end 86 is spaced slightly rearwardly of the lower end 69 of yoke 65.

When the pump lever 36 is again pivoted about pin 40 to prepare the carbine for firing-another BB, the piston 30 will again strike the forward end 84 of cocking barrel 15 by the pressure of spring 97 and the remaining BBs in the magazine. When the last BB in the magazine has been fed into firing position it is held there by the curved end 102 of leaf spring 100. Except at this time this leaf spring rides in the magizine on the adjacent part of the wall of the magazine and is held in the recess 104 of the rod.

To cock the gun, lever 36 is rocked downwardly manually about pin 40, thereby causing links 44 to draw block 35 forwardly in sleeve 20. This causes piston rod 34 to advance piston 30 incylinder 23 far enough for the piston to strike and urge the forward end 84 of rod 80 forwardly far enough for its rear end 86 to engage the lower end 69 of the yoke 65, to swing the yoke counterclockwise (FIG. 1). When the bottom portion 69 of the yoke reaches the position illustrated in FIG. 1, a spring (not illustrated) attached to the trigger 74 causes the trigger to be swung upwardly or counterclockwise (FIG. 1) about pin 71 until the sear portion 75 passes behindthe lower end 69 of the yoke releasably to maintain. the yoke in cocked position.

- The lever 36 is swung manually upwardly about pivot pin to drive piston 30 from the forward end toward the rear end of cylinder 23. This compresses the air in the cylinder between the piston 30 and the valve block 25, and causes the compressed air to be delivered through duct 52 into air pressure chamber 50. The ratio of the volume of air displaced by piston'30 to the volume of chamber is such that with a single stroke of the pump arm 36 the pressure built up in chamber rod 80 causing the rod once again to engage the lower end 69 of yoke to return the yoke to its cocked position in front of the trigger sear 75. Also, during the compression stroke of the piston 30, the air in cylinder 23 once again will be compressed into the chamber 50 as noted above.

It will be apparent that when a plurality of BBs are placed in the magazine, rod 94 will cause them tobe advanced one after another into firing position. It will be apparent also thatv whenever the rear end of rod 94 is retracted into the magazine 92, the free end 102 of spring 100 will be forced radially inwardly into the recess 104 in the rear end of the rod. I Y

From the foregoing, it will be apparent that the instant invention provides an extremely compact and reliable pump-type carbine, which utilizes a minimum of moving parts in its firing mechanism. Moreover, spring 87 is the only spring which plays any major part in the cooking and firing mechanism of the gun; andit is used merely as a return spring to maintain the cocking rod in its retracted position. There are no springs directly connected to the valve member 60. In addition, the gun is'extremelysilent in operation, since it does not utilize a hammer 'for striking and opening a valve as is the case in most prior such guns.

Still another advantage of the carbine disclosed herein is that the ratio of the displacement of the piston 30 that is the ratio of the volume of the pump cylinder 23, when the piston is in withdrawn, forward position, to the volume of the pressure chamber 50, is such that but a single operation of lever 36 suffices to compress air in the chamber 50 enough to drive a BB out of the barrel 15 with a satisfactory muzzle velocity. In one embodiment of the invention the pump cylinder 23 has 2.3 cu. in. capacity and the pressure chamber 50 has a volume of 1.0311 cu. in. r

While the invention has been described in connection with a specific embodiment thereof it will be understood that it is capable of further modification, and this application is intended to cover any embodiments of the invention coming within the disclosure or the recital of the appended claims.

Having thus described my invention, what I claim is:

1,. A pump-type air gun comprising a frame having therein an air pressure chamber,

a barrel secured in said frame,

manually operable pump means on said frame for filling said chamber with a supplyof compressed air,

a tubular valve member slidable in said chamber and having its bore aligned with the bore of said barrel,

means for positioning a projectile between said valve member and said barrel in registry with said barrel,

a valve seat in said chamber,

means for releasably holding said valve member in a cocked position in which the bore of said valve member is closed by said seat,

a releasable trigger operable to release said holding means so that the compressed air in said chamber moves said valve member off its seat and the compressed air from said chamber flows through the bore of said valve member to the rear of the projectile to propel the projectile from the barrel; and

means connecting said valve member to said pump means and operative to return said valve member to its cocked position each time said pump means is operated.

2. A pump gun as defined in claim 1, whereinsaid valve seat comprises a projection at one end of said chamber which projects slidably and sealingly into one end of said bore in said valve member, when the latter is in its cocked position. v

3. A pump gun as defined'in claim 1, wherein said pump means comprises a piston mounted to reciprocate in a cylinder in said frame, a duct connects said cylinder with said chamber'to supply compressed air thereto, and

said connecting means comprises a reciprocable member projecting atone end into said cylinder for reciprocation by said piston each time the latter is reciprocated, and

means connecting the opposite end of said reciprocable member to said holding means and operative to cause said holding means to move said valve 'member from its fired to its cocked position each time said reciprocable member is reciprocated.

4. A pump gun as defined in claim 3, wherein said valve member is reciprocable into and out of the rear end of said barrel, and said positioning means is operative to feed a projectile into a space between said barrel and said valve member each time said valve member is moved from fired to cocked position.

5. A pump gun as defined in claim 3, wherein said valve seat comprises a stationary element in said chamber disposed to project slidably into engagement with the bore of said valve member at the rear end thereof to seal said bore, when said valve member is in cocked position,

said holding means comprises a member pivotally mounted on said frame and connected at one end to said valve member and at its opposite end to said opposite end of said reciprocable member, and

said trigger is operable releasably to hold said pivotal member in an operative position in which the pivotal member blocks movement of said valve member from cocked to fired position.

6. A pump gun, comprising a frame having therein a chamber,

a barrel mounted in said frame forwardly of said chamber,

a tubular valve member mounted in said frame to reciprocate axially between cocked and fired positions, respectively, and projecting slidably at one end into said chamber, and having its bore registering with the bore in said barrel, but spaced rearwardly from said barrel when said valve member is in cocked position,

means in said chamber for releasably sealing the bore in said valve member when the latter is in its cocked position,

manually operable means for moving said valve member from fired to cocked position,

means for feeding a missile into the space between said valve member and said barrel, when said valve member is cocked,

means for automatically supplying gas under pressure to said chamber each time said valve member is moved to its cocked position, and

a trigger for releasably holding said valve member in cocked position,

said valve member having on said one end thereof an operating surface extending transverse to the axis of its bore and disposed in spaced relation to the rear wall of said chamber when the valve member is in cocked position, whereby upon release of said valve member by said trigger the pressure of gas in said chamber against said operating surface causes said valve member to be urged to fired position to admit gas from said chamber into the bore of said valve member to fire the missile from the gun.

7. A pump gun as defined in claim 6, wherein said manually operable means comprises a lever pivotally mounted on said frame,

a cocking member mounted on said frame for reciprocation by said lever each time the latter is oscillated about its pivotal axis, and

a second, movable member interposed between said valve member and said cocking member to be moved from an operative to an inoperative position by said valve member each time the latter is moved to itsfired position, and to be moved to its operative position each time said cocking member is reciprocated,

said second member being operative to move said valve member to its cocked position, when said second member is moved to its operative position, and

said trigger having thereon a sear releasably engageable with said second member to hold the latter in its operative position when said valve member is in cocked position.

8. A pump gun as defined in claim 7, wherein said means for supplying gas to said chamber comprises a piston mounted to reciprocate in a cylinder on said frame,

means connecting said piston to said lever for reciprocation thereby each time said lever is oscillated, and

duct means connecting one end of said cylinder to said chamber to supply compressed air to said chamber each time said piston is moved in one direction.

9. A pump gun as defined in claim 8, wherein said sealing means comprises a stationary stud projecting into said chamber to extend slidably part way into the bore of said valve member when the latter is in its cocked position thereby to seal the last-named bore.

10. A pump gun comprising a frame having a pressure chamber therein,

a pump comprising a cylinder and a piston reciprocable therein,

means for admitting air to one side of said piston,

a first lever pivoted to said frame and connected to said piston to compress the air on movement of said piston in said cylinder in one direction,

a duct connecting said cylinder with said chamber to convey the compressed air to said chamber,

means for positioning a missile in firing position in said gun,

a valve for closing said chamber,

a second lever pivoted on said frame and operatively connected to said first lever for movement to a cocked position in which it closes said valve, when said first lever is pivoted, and

trigger means for releasably holding said second lever in said cocked position and operable manually to release said second lever thereby to open said valve to supply the compressed air from said chamber to amissile, which is in firing position, to fire the missle from the gun,

the ratio of the volume of said cylinder, when said piston is at the limit of its movement in the opposite direction in said cylinder, to the volume of said chamber being such that one movement of said piston in said one direction is sufficient to supply compressed air to said chamber under pressure sufficient to fire a missile from the gun,

said valve comprising a tubular member,

there being a seat in said chamber positioned to engage in one end of said tubular member, when said second lever is in cocked position to close the bore in said tubular member,

said second lever being engageable with a shoulder on said tubular member releasably to hold said tubular member on its seat,

the bore of said tubular member being aligned with the bore of the gun barrel, and

said positioning means being operative to dispose a missile between said tubular member and said barrel coaxially of their respective bores so that compressed air flows from said chamber through the bore of said tubular member to fire the missile through the gun barrel when the trigger is actuated to release said holding means.

Claims

1. A pump-type air gun comprising a frame having therein an air pressure chamber, a barrel secured in said frame, manually operable pump means on said frame for filling said chamber with a supply of compressed air, a tubular valve member slidable in said chamber and having its bore aligned with the bore of said barrel, means for positioning a projectile between said valve member and said barrel in registry with said barrel, a valve seat in said chamber, means for releasably holding said valve member in a cocked position in which the bore of saiD valve member is closed by said seat, a releasable trigger operable to release said holding means so that the compressed air in said chamber moves said valve member off its seat and the compressed air from said chamber flows through the bore of said valve member to the rear of the projectile to propel the projectile from the barrel, and means connecting said valve member to said pump means and operative to return said valve member to its cocked position each time said pump means is operated.

2. A pump gun as defined in claim 1, wherein said valve seat comprises a projection at one end of said chamber which projects slidably and sealingly into one end of said bore in said valve member, when the latter is in its cocked position.

3. A pump gun as defined in claim 1, wherein said pump means comprises a piston mounted to reciprocate in a cylinder in said frame, a duct connects said cylinder with said chamber to supply compressed air thereto, and said connecting means comprises a reciprocable member projecting at one end into said cylinder for reciprocation by said piston each time the latter is reciprocated, and means connecting the opposite end of said reciprocable member to said holding means and operative to cause said holding means to move said valve member from its fired to its cocked position each time said reciprocable member is reciprocated.

5. A pump gun as defined in claim 3, wherein said valve seat comprises a stationary element in said chamber disposed to project slidably into engagement with the bore of said valve member at the rear end thereof to seal said bore, when said valve member is in cocked position, said holding means comprises a member pivotally mounted on said frame and connected at one end to said valve member and at its opposite end to said opposite end of said reciprocable member, and said trigger is operable releasably to hold said pivotal member in an operative position in which the pivotal member blocks movement of said valve member from cocked to fired position.

6. A pump gun, comprising a frame having therein a chamber, a barrel mounted in said frame forwardly of said chamber, a tubular valve member mounted in said frame to reciprocate axially between cocked and fired positions, respectively, and projecting slidably at one end into said chamber, and having its bore registering with the bore in said barrel, but spaced rearwardly from said barrel when said valve member is in cocked position, means in said chamber for releasably sealing the bore in said valve member when the latter is in its cocked position, manually operable means for moving said valve member from fired to cocked position, means for feeding a missile into the space between said valve member and said barrel, when said valve member is cocked, means for automatically supplying gas under pressure to said chamber each time said valve member is moved to its cocked position, and a trigger for releasably holding said valve member in cocked position, said valve member having on said one end thereof an operating surface extending transverse to the axis of its bore and disposed in spaced relation to the rear wall of said chamber when the valve member is in cocked position, whereby upon release of said valve member by said trigger the pressure of gas in said chamber against said operating surface causes said valve member to be urged to fired position to admit gas from said chamber into the bore of said valve member to fire the missile from the gun.

7. A pump gun as defined in claim 6, wherein said manually operable means comprises a lever pivotally mounted on said fraMe, a cocking member mounted on said frame for reciprocation by said lever each time the latter is oscillated about its pivotal axis, and a second, movable member interposed between said valve member and said cocking member to be moved from an operative to an inoperative position by said valve member each time the latter is moved to its fired position, and to be moved to its operative position each time said cocking member is reciprocated, said second member being operative to move said valve member to its cocked position, when said second member is moved to its operative position, and said trigger having thereon a sear releasably engageable with said second member to hold the latter in its operative position when said valve member is in cocked position.

8. A pump gun as defined in claim 7, wherein said means for supplying gas to said chamber comprises a piston mounted to reciprocate in a cylinder on said frame, means connecting said piston to said lever for reciprocation thereby each time said lever is oscillated, and duct means connecting one end of said cylinder to said chamber to supply compressed air to said chamber each time said piston is moved in one direction.

10. A pump gun comprising a frame having a pressure chamber therein, a pump comprising a cylinder and a piston reciprocable therein, means for admitting air to one side of said piston, a first lever pivoted to said frame and connected to said piston to compress the air on movement of said piston in said cylinder in one direction, a duct connecting said cylinder with said chamber to convey the compressed air to said chamber, means for positioning a missile in firing position in said gun, a valve for closing said chamber, a second lever pivoted on said frame and operatively connected to said first lever for movement to a cocked position in which it closes said valve, when said first lever is pivoted, and trigger means for releasably holding said second lever in said cocked position and operable manually to release said second lever thereby to open said valve to supply the compressed air from said chamber to a missile, which is in firing position, to fire the missle from the gun, the ratio of the volume of said cylinder, when said piston is at the limit of its movement in the opposite direction in said cylinder, to the volume of said chamber being such that one movement of said piston in said one direction is sufficient to supply compressed air to said chamber under pressure sufficient to fire a missile from the gun, said valve comprising a tubular member, there being a seat in said chamber positioned to engage in one end of said tubular member, when said second lever is in cocked position to close the bore in said tubular member, said second lever being engageable with a shoulder on said tubular member releasably to hold said tubular member on its seat, the bore of said tubular member being aligned with the bore of the gun barrel, and said positioning means being operative to dispose a missile between said tubular member and said barrel coaxially of their respective bores so that compressed air flows from said chamber through the bore of said tubular member to fire the missile through the gun barrel when the trigger is actuated to release said holding means.