Mechanical guns and projectors – Fluid pressure
Reexamination Certificate
2002-01-28
2004-07-27
Jordan, Charles T. (Department: 3644)
Mechanical guns and projectors
Fluid pressure
C042S075030
Reexamination Certificate
active
06766795
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to guns, including guns for use in the sport of paintball.
BACKGROUND OF THE INVENTION
Conventional firearms have a firing mechanism to fire a projectile and a barrel to direct the projectile in a desired direction. Guns are made for numerous purposes and include many designs, for example, rifles, shot guns, and hand guns. A broad array of different mechanisms for firing a projectile have been employed for various types of guns. For example, one type of gun is dependant on having a propellant combined with the projectile. In this type of gun, the firing mechanism detonates the propellant contained in the projectile, which launches the projectile along the barrel. This type includes shot guns, which fire cartridges comprised of shot packaged with explosive material, and conventional rifles, machine guns, and handguns, which shoot bullets comprised of a unitary slug packaged with explosive material in a casing.
Another method of firing a projectile uses a propulsion source separate from the projectile, such as compressed gas, including air, carbon dioxide, nitrogen, and others. Examples of such guns include, air riffles, BB guns, and paintball guns or “markers.” These guns either include a pump for compressing ambient air or are adapted to receive compressed air from a source, such as a compressed gas cartridge or gas cylinder. Conventional paintball guns rely on such cartridges or gas cylinders for supplying compressed gas, including air, nitrogen and carbon dioxide.
FIG. 13
illustrates the general components of a prior-art open-bolt, blow-back paintball gun. Gun
1
′ comprises a grip
4
′ and a receiver
6
′. Grip
4
′ is attached to receiver
6
′ by bolts
2
′,
2
′. Grip
4
′ comprises a frame
8
′ housing a trigger
9
′ and sear
12
′ for actuating the firing sequence of gun
1
′ to fire the projectile, such as a paintball
15
′ (shown in shadow). As described in greater detail below, a firing mechanism is powered by a volume of compressed gas supplied from a compressed gas source (not shown).
As shown in
FIG. 13
, receiver
6
′ comprises a first bore
22
′ and a second bore
23
′. The second bore
23
′ is adapted to receive valve body
52
′, which partitions second bore
23
′ into a first chamber
24
′ and second chamber
26
′. Valve body
52
′ has coaxial bores
53
′ and
54
′, which are transverse to bore
59
′, which act as fluid ports
53
′ and
54
′ and
59
′. The diameters of bores
53
′,
54
′ and
59
′ are selected to achieve a ratio of fluid flow between port
54
′ and
59
′ to accommodate the proper firing and reload functions of the gun, as described below. Valve body
52
′ is sealed by
0
-rings
48
′ and
50
′, and secured in receiver
6
′ by bolt
56
′. Poppet
51
′ is seated in ports
53
′ and
54
′ and maintained by spring (not shown). Poppet
51
′ is comprised of valve pin
60
′ and valve cup seal
62
′. Valve cup seal
62
′ is threaded on valve pin
60
′.
Receiver
6
′ further houses a firing assembly
25
′ comprising a rear housing
27
′, a hammer
29
′, and a firing bolt
31
′. In particular, firing bolt
31
′ is housed in first bore
22
′ and hammer
29
′is housed in second chamber
26
′. Firing bolt
31
′ is further attached to a cocking shaft, which passes through the rear housing
27
′ and terminates in a cocking knob
33
′. Rear housing
27
′partially houses and retains spring retainer
37
′, which supports spacer
38
′ and spring
39
′. Spring
39
′ fits in hammer
29
′, which is connected to firing bolt
31
′ by pin
42
′. Bolt
34
′ may be rotated to increase or decrease tension on spring
39
′, which in turn adjusts the speed with which hammer
29
′ is released and, as a result, controls the amount of compressed air that is released, which ultimately controls the velocity of the paintball when fired. Firing assembly
25
′ is secured in receiver
6
′ by pin
36
′.
Pulling back on the cocking knob
33
′ pulls firing bolt
31
′ toward the ready (cocked) position. Because firing bolt
31
′ is connected by pin
42
′ to hammer
29
′, hammer
29
′ is also drawn back until hammer
29
′ deflects sear
12
′, and sear
12
′ engages hammer catch
47
′ on hammer
29
′. When hammer catch
47
′ is so engaged by sear
12
′, hammer
29
′ is in the ready position. When trigger
9
′ is pulled, trigger
9
′ rotates sear
12
′ around pin
49
′, disengaging hammer
29
′ from sear
12
′ and releasing hammer
29
′ into the firing position, thus initiating the firing sequence, described as follows.
When hammer
29
′ hits valve pin
60
′ of poppet
51
′, poppet
51
′ is unseated from port
53
′, and pressurized air contained in first chamber
24
′ is released through port
53
′ and discharges through valves
54
′ and
59
′. At this point in the firing sequence, when hammer
29
′ is near the valve pin
60
′ (the firing position), bolt port
57
′ is aligned with port
59
′. Thus, when compressed air is released from first chamber
24
′, some of this air flows through port
59
′, which then flows through bolt port
57
′ to fire projectile
15
′.
Meanwhile, the remaining portion of air, which flows through port
53
′ but does not flow through bolt port
59
′, instead flows through port
54
′. This air creates pressure in blow-back chamber
63
′, which is formed by second chamber
26
′ and hammer
29
′, creating air pressure against hammer
29
′ to recoil (or “blow back”) hammer
29
′ toward the ready position, until sear
12
′ engages hammer catch
47
′. Vent
64
′ releases the air pressure in the blow-back chamber
63
′ as the hammer
29
′ is propelled into the ready position, so that hammer
29
′ may fire again in the next round. After hammer
29
′displaces poppet
51
′, tension from spring (not shown) along with compressed air pressure against poppet
51
′ reseats poppet
51
′, closing port
53
′. Gun
1
′ is now recocked and ready for firing. This firing sequence is known as semi-automatic, because the gun automatically recocks itself after firing.
As will be understood by one of skill in the art, the balance of compressed gas flowing between ports
54
′ and
59
′ will affect the velocity of the projectile
15
′ and the velocity that hammer
29
′ is “blown back”. One way of apportioning the amount of air that flows through either port
54
′ or port
59
′ of valve body
52
′ is established by the respective diameters of ports
54
′and
59
′. Another way of establishing the respective air flow between port
54
′ and
59
′ is by adapting a non-circular cross-section for valve pin
60
′. For example, valve pin
60
′ may be provided with a longitudinal cut away or groove, which allows additional airflow through port
54
′. These variables may be adjusted by those skilled in the art to achieve an optimum balance for gas efficiency and firing velocity.
A drawback to conventional blow-back paintball guns
1
′ makes it difficult to replace the hammer
29
′ after disassembly after cleaning. When hammer
29
′ is removed from receiver
6
′, the sear
12
′ extends into receiver
6
′ and blocks the path of hammer
29
′, preventing hammer
29
′ from returning into receiver
6
′. In conventional blow-back paintball guns
1
′,
Jordan Charles T.
Neal Gerber & Eisenberg LLP
Pursuit Marketing, Inc.
Zerr John W.
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