Fluid handling – Convertible – Unit orientable in a single location between plural positions
Reexamination Certificate
2001-11-05
2003-04-15
Scherbel, David A. (Department: 3754)
Fluid handling
Convertible
Unit orientable in a single location between plural positions
C251S012000, C124S073000
Reexamination Certificate
active
06546950
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a lacquer bullet gun gas entry valve, particularly to a lacquer bullet gun gas entry valve providing controlled entry of compressed gas.
2. Description of Related Art
As shown in
FIG. 5
, a conventional lacquer bullet gun mainly comprises: a gun case
1
; a barrel
2
at a front end of the gun case
1
; a bullet chamber
3
at a rear end of the barrel
2
; a feeding hole
4
above the bullet chamber
3
, feeding one lacquer bullet
5
at a time into the bullet chamber
3
, which are subsequently driven out through the barrel
2
by compressed gas; a firing device
6
inside the gun case
1
, performing rearward and forward movements, while moving forward pushing the lacquer bullet
5
into the bullet chamber
3
to be fired; a gas container
8
, supplying compressed gas through a pressure-reducing valve
9
into an expansion chamber
10
, which is located below the bullet chamber
3
and connected thereto by a conduit
11
; and a gas entry valve
12
. The gas entry valve
12
further comprises: a valve body
13
, a shutter
15
, a spring
16
and a piston
17
. The valve body
13
is placed in the expansion chamber
10
at an entrance of the conduit
11
and has a central axis, defining a longitudinal direction, along which a passageway
14
runs. An opening
141
is placed on an upper side of the passageway
14
, being aligned with the conduit
11
, so that the passageway
14
and the conduit
11
are connected. The shutter
15
is located on the central axis of the valve body
13
, having a sealing element for sealing the shutter
15
against the valve body
13
, preventing gas from entering the passageway
14
within the valve body
13
. A rod
151
is attached to the shutter
15
and passes through the passageway
14
along the longitudinal direction, having a rear end that reaches out of a rear side of the valve body
13
opposite to the shutter
15
. The spring
16
pushes the shutter
15
tight on the valve body
13
. The piston
17
is connected to a lower part of the firing device
6
, glidingly moving within the expansion chamber
10
.
When the firing device
6
moves forward, the piston
17
moves along and pushes the rod
151
forward, causing the shutter
15
to separate from the valve body
13
and allowing compressed gas to enter the bullet chamber
3
through the passageway
14
in the valve body
13
to drive out the lacquer bullet
5
through the barrel
2
. When the shutter
15
opens, pushed by the piston
17
, gas partly enters a rear section of the expansion chamber
10
through a gap between the rod
151
and a rear end of the passageway
14
, pushing the piston
17
rearward, so that the firing device
6
returns to a ready state, as before firing.
For controlling gas flow into the rear section of the expansion chamber
10
and pressure exerted there to prevent too large a pressure from pushing the piston
17
rearward too fast and, on the other hand, to create sufficient pressure to push the piston
17
rearward, the rear end of the rod
151
carries a blocking part
153
. The blocking part
153
has several longitudinal grooves
154
and has a diameter that is equal to the diameter of the passageway
14
. Thus gas from the passageway
14
is blocked from passing, except for the grooves
154
. The number and widths of the grooves
154
determine the flow of gas into the rear section of the expansion chamber
10
and gas pressure there, controlling gas pressure on the piston
17
.
The number and width of the grooves
154
needs to be adapted to the compressed gas pressure at which the lacquer bullet gun operates for the lacquer bullet gun to work regularly. However, various gases are used as driving agents which have various operating pressures. Nowadays, mainly carbon dioxide and nitrogen are used, with carbon dioxide having a larger operating pressure than nitrogen. Therefore, using nitrogen as a driving agent requires a larger number of grooves
154
at the rear end of the rod
151
at the shutter
15
to form a wider path for gas to flow into the rear section of the expansion chamber
10
to develop sufficient pressure on the piston
17
. If, on the other hand, carbon dioxide is used as a driving agent, the number or widths of the grooves
154
has to be reduced, so as to reduce pressure on the piston
17
and preventing the piston
17
from moving back too fast.
Adapting the gas entry valve to various driving agents with various operating pressures requires different designs thereof. Especially, when carbon dioxide as a driving agent is replaced by nitrogen, pressure to push back the piston
17
is insufficient. When nitrogen as a driving agent is replaced by carbon dioxide, pressure to push back the piston
17
is too large, possibly resulting in breakdowns. Conventional lacquer bullet guns are thus restricted to one type of driving agents, which is rather inconvenient.
Since gas entry valves for two different driving agents cannot be exchanged, two types of gas entry valves for lacquer bullet guns have to be employed, increasing working effort and cost of production.
SUMMARY OF THE INVENTION
It is the main object of the present invention to provide a lacquer bullet gun gas entry valve, allowing to use various driving agents for the lacquer bullet gun without modification.
Another object of the present invention is to provide a lacquer bullet gun gas entry valve, allowing to use two agents for the lacquer bullet gun at the same time for better convenience.
The present invention can be more fully understood by reference to the following description and accompanying drawings.
REFERENCES:
patent: 2594185 (1952-04-01), Lefever
patent: 5613483 (1997-03-01), Lukas et al.
patent: 5669369 (1997-09-01), Scott
patent: 5791328 (1998-08-01), Alexander
patent: 6360736 (2002-03-01), Juan
patent: 6418920 (2002-07-01), Marr
Bastianelli John
Pro-Techtor Inter-national Services
Scherbel David A.
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