Compressed air gun with single action pump

An air compressed gun (10) is provided having a stock (11), a barrel (12), a pressure chamber (16), a pressure actuatable release valve (18) and a manual air pump (14). The pump has an elongated cylinder (25) having a port (38) in fluid communication with the release valve, and a plunger (26) telescopically mounted for reciprocal movement within the cylinder. The plunger has an O-ring type seal (31). The forward movement of the plunger seal towards the port pressurizes air within the cylinder which is transferred to the release valve and pressure chamber. The continued movement of the plunger seal past the port causes a portion of the pressurized air to be released so as to actuate the pressure actuatable release valve to release the pressurized air within the pressure chamber into the barrel.

TECHNICAL FIELD 
This invention relates to compressed air guns, and specifically to 
compressed air guns having pumps which pressurize air and trigger the 
release of the pressurized air. 
BACKGROUND OF THE INVENTION 
Guns which shoot or launch projectiles have been very popular for many 
years. These guns have been designed to launch projectiles in a number of 
ways. A common method of launching has been by the compression of a spring 
which propels the projectile upon its decompression or release, as, for 
example, with BB guns and dart guns. These guns however usually do not 
generate enough force to launch projectiles with great velocity. 
Toy guns have also been designed which use compressed air to launch 
projectiles such as foam darts. These types of guns use a reciprocating 
air pump to pressurize air within a pressure tank. In use, the pump is 
typically reciprocated several times to pressurize air which is later 
released through actuation of a trigger. Therefore, children must actuate 
two components in order to fire a projectile. Additionally, this dual 
actuation may be undesired when time is of the essence and a rapid 
pressurization and firing of the gun is desired. 
Accordingly, it is seen that a need remains for an air gun which may be 
rapidly pressurized and fired. It is to the provision of such therefore 
that the present invention is primarily directed. 
SUMMARY OF THE INVENTION 
In a preferred form of the invention a compressed air gun comprises a 
projectile launch tube, a pressure chamber in fluid communication with the 
launch tube, a pressure actuatable release valve means for triggering the 
release of pressurized air from the pressure chamber into the launch tube, 
and a manual air pump. The manual air pump has a vented air cylinder with 
an open end, a closed end and a port spaced from the closed end, and a 
plunger that extends into the cylinder through the cylinder open end. The 
plunger has a seal mounted in sliding, sealing engagement with the 
cylinder. With this construction, an inward stroke of the plunger seal 
toward the cylinder port pumps air into the pressure chamber through the 
release valve means and passage of the plunger seal past the port actuates 
the release valve means which triggers the release of pressurized air from 
the pressure chamber into the launch tube.

DETAILED DESCRIPTION 
With reference next to the drawings, there is shown a compressed air gun 10 
having a stock 11, a barrel or launch tube 12 mounted to the stock 11, and 
a manual air pump 14. The air pump may be made of a clear plastic as shown 
in FIG. 1. The gun 10 has a pressure chamber 16 in fluid communication 
with the air pump 14 through a pressure tube 17, and a pressure actuatable 
release valve 18 mounted within the pressure chamber 16. Pressure chamber 
16 is adapted to receive and store a supply of air at elevated pressure 
levels. The pressure chamber 16 has an air exit opening 19 in fluid 
communication with an end of barrel 12 which is positioned to cooperate 
with release valve 18. The release valve 18 has a cylindrical manifold 21 
and a cylindrical plunger 22 slidably mounted within the manifold 21 for 
reciprocal movement therein. Plunger 22 has a gasket 23 which ensures 
sealing engagement of the plunger about pressure chamber opening 19 with 
the plunger in a closed position. 
The pump 14 includes an elongated cylinder 25 and a plunger 26 
telescopically mounted for reciprocal movement within the cylinder 25. 
Plunger 26 has a tubular shaft 27 with an enlarged sealing end 28 and a 
handle 29 opposite the sealing end 28. Sealing end 28 has an O-ring type 
seal 31 with an opening 32 therethrough, and a conventional check valve 33 
mounted within opening 32 oriented to allow air to pass from the interior 
of cylinder 25 through opening 32 into the interior of shaft 27 and to 
prevent air from passing through opening 32 in the opposite direction. 
Handle 29 has a vent 34 therethrough which allows air to pass from 
ambience into the interior of shaft 27. 
Pump cylinder 25 has an open end 36 through which plunger 26 extends and a 
closed end 37. The cylinder 25 also has a port 38 in fluid communication 
with pressure tube 17 and a vent 39 adjacent open end 36 which is open to 
ambience. Port 38 is spaced from closed end 37 so as to allow seal 31 of 
plunger 26 to be moved past the port 38 to a position closely adjacent to 
the closed end 37 as shown in FIG. 3. 
In use, an operator actuates the pump 14 by grasping the handle 29 and 
forcing the plunger 26 from a position with sealing end 28 adjacent 
cylinder open end 36, as shown generally in phantom lines in FIG. 2, 
through cylinder 25 towards port 38 thereby pressurizing air within the 
cylinder and pressure tube 17. The pressurized air flows through port 38 
into pressure tube 17 where it then flows through pressure tube 17 into 
release valve manifold 21. The increase in air pressure within the release 
valve manifold 21 forces the valve plunger 22 to move to a forward 
position sealing opening 19, as shown in FIG. 2. The pressurized air then 
flows between the valve plunger 22 and the valve manifold 21 into pressure 
chamber 16 thereby pressurizing the air in chamber 16. 
With continued movement of the plunger 22 within cylinder 25 the plunger 
seal 31 of the pump passes past port 38, as shown in FIG. 3. With the 
plunger seal 31 in this position pressurized air within pressure tube 17 
is released back into cylinder 25 behind seal 31 and to ambience through 
vent 39. The reentry of pressurized air into the cylinder 25 from pressure 
tube 17 causes the release valve plunger 22 to move to a rearward position 
unsealing opening 19 as shown in FIG. 3. Thus, the decrease in air 
pressure within the pressure tube 17 and release valve manifold 21 
triggers the actuation of release valve 18 to its open configuration. With 
the unsealing of opening 19 pressurized air within pressure chamber 16 
rapidly flows through opening 19 into the barrel 12 where it propels the 
projectile P from the barrel, as shown in FIG. 1. As air flows out of the 
pressure chamber into the launch chamber, only the slightest amount of air 
also back flows from the pressure chamber into the release valve manifold 
21 since the plunger abuts the manifold. Operation of this type of release 
valve is described in more detail in U.S. Pat. No. 4,159,705. 
Once the gun has been fired the plunger 26 may be manually reciprocated 
back to its initial position. The drawing back of the plunger does not 
create a vacuum within cylinder 25 since replenishment air may be drawn 
through vent 34 into the plunger handle 29, through the interior of shaft 
27, and through check valve 33 into cylinder 25. Air between the cylinder 
25 and the plunger 26 behind seal 31 is forced from cylinder 25 through 
vent 39. 
The just described gun has the capability of being rapidly pressurized and 
fired in one continuous stroke. This allows a person to operate the gun 
with a quick, single stroke, rather than having to pressurize the gun and 
then actuate a trigger as with guns of the prior art. Additionally, it 
should be understood that the pump may be actuated so that the plunger is 
moved to a position close to its firing position so as to pressurize air 
and maintain the pressurized air in stored condition for later firing upon 
final movement of the plunger past port 38. In this mode manual pressure 
must be maintained to prevent the plunger 26 from retreating. 
It should be understood that the just described air gun may also be adapted 
to cooperate with a rocket, as such it would be designed to resemble a 
rocket launcher rather than a conventional gun. The rocket may be adapted 
to be received within the launch tube or be adapted to receive the launch 
tube within a recess in the tail end of the rocket similarly to 
conventional toy rockets of the prior art. 
While this invention has been described in detail with particular 
references to the preferred embodiment thereof, it should be understood 
that many modifications, additions and deletions may be made thereto 
without departure from the spirit and scope of the invention as set forth 
in the following claims.