JP4075353B2 - Gas nailer - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a gas nailing machine in which flammable gas and air are mixed and ignited to generate power for driving a piston and to drive a nail by the piston.
[0002]
[Prior art]
In general, a gas nailer has a structure shown in, for example, US Pat. No. 5,1976,646. A procedure for driving a nail will be described with reference to FIGS. FIG. 4 shows a stationary state before driving. The housing 14 forming the main body frame is accompanied by a handle 11, a tail cover 1, a push lever 21, a magazine 13, and a trigger switch 12. Inside the housing 14, a cylinder 4, a bumper 2, a piston 10, a fan 6, A motor 8 for rotating the fan 6, a spark plug 9, an injection port 22, a gas cylinder 7, a combustion chamber wall 15, a head cover 23, and the like are provided.
[0003]
In the housing 14, the cylinder 4 and the head cover 23 are fixed with respect to the housing 14, but the combustion chamber wall 15 is guided by the housing 14 and the cylinder 4 and is urged downward by a spring (not shown). It can move in the direction. A space closed by the combustion chamber wall 15, the head cover 23, and the piston 10 forms a combustion chamber 5 in which a mixed gas of combustible gas and air burns. A piston 10 is movably provided in the cylinder 4 via a sliding seal member (not shown). An exhaust hole 3 on the lower side wall of the cylinder 4 and a check valve (not shown) and a bumper 2 for stopping the piston 10 are provided outside the exhaust hole 3. Inside the combustion chamber 5, a fan 6 rotated by a motor 8 provided above the head cover 23 outside the combustion chamber 5, a spark plug 9 ignited by a trigger switch 12, and provided outside the combustion chamber 5, is a combustible gas. There are an injection port 22 for injecting a gas supplied from a gas cylinder 7 including a rib 24 protruding in a protruding shape.
[0004]
A magazine 13 filled with nails (not shown) below the housing 14 and a tail cover 1 for supporting the nails at the head of the nails fed from the magazine 3 below the piston 10 and guiding the nails and the piston are attached.
[0005]
Sealing members (not shown) are provided at the upper end of the cylinder 4 and the lower end of the head cover 23.
[0006]
In the stationary state shown in FIG. 4, the push lever 21 protrudes from the lower end of the tail cover 1 due to the spring bias. At this time, there is a gap 25 between the lower side of the combustion chamber 5 connected to the push lever 21 and the upper end of the cylinder 4, and at the same time, there is a gap 26 between the upper end of the combustion chamber 5 and the lower side of the head cover 23. The piston 10 is stopped at the top dead center position in the cylinder 4.
[0007]
When the handle 11 is gripped in this state and the push lever 21 is pressed against the wood 27, the push lever 21 rises against the spring, and the combustion chamber wall 15 connected to the push lever 21 also rises as shown in FIG. Become. As the combustion chamber wall 15 rises, the gaps 25 and 26 below and above the combustion chamber 5 are closed and sealed with a sealing material. In conjunction with the above operation, after that, the gas cylinder 7 is pressed, the combustible gas is injected from the injection port 22, the motor 8 is turned on, and the fan 6 rotates. As the fan 6 rotates in the combustion chamber 5 which is a sealed space, the injected gas is mixed with the air in the combustion chamber 5 together with the ribs 24 protruding into the combustion chamber 5.
[0008]
Thereafter, when the trigger switch 12 is turned on, the spark plug 9 sparks to ignite the mixed gas. The burned / expanded gas moves the piston 10 downward, drives a nail in the tail cover 1, and the state shown in FIG.
[0009]
In FIG. 6, the piston 10 is in contact with the bumper 2. Combustion gas is discharged from the exhaust hole 3 to the outside of the cylinder 4. The exhaust hole 3 is accompanied by a check valve. When the combustion gas is discharged to the outside of the cylinder 4 and the inside of the cylinder 4 and the combustion chamber 5 becomes atmospheric pressure, the check valve is closed. The combustion gas remaining in the cylinder 4 and the combustion chamber 5 is high temperature because it is after combustion, and the heat is absorbed from the inner wall of the cylinder 4 and the inner wall of the combustion chamber wall 15, whereby the combustion gas is rapidly cooled, The pressure in the closed space above the piston 10 is reduced to atmospheric pressure (referred to as thermal vacuum), and the piston 10 is pulled back to the initial top dead center position.
[0010]
After that, when the trigger switch 12 is turned off, the main body is lifted, and the push lever 21 is separated from the wood 27, the push lever 21 and the combustion chamber wall 15 return downward due to the spring bias, as shown in FIG. At this time, even if the fan 6 is turned off, the fan 6 continues to rotate for a predetermined time by a control unit (not shown). In the state shown in FIG. 7, gaps 25 and 26 are formed above and below the combustion chamber 5, and a flow 16 is generated by the fan 6 to scavenge the air after combustion. Thereafter, the fan 6 stops and enters an initial stationary state (FIG. 4).
[0011]
[Problems to be solved by the invention]
In the gas nailer described above, when the piston 10 is pulled back by thermal vacuum after the nail is driven, the flow by the fan 6 is very weak below the cylinder 4 and the cooling efficiency in the cylinder 4 is poor. The return time of 10 is long, which greatly affects the repeated firing of nails.
[0012]
An object of the present invention is to improve the cooling efficiency in the cylinder by generating forced convection inside the cylinder, thereby shortening the return time of the piston and enabling repeated nail hitting.
[0013]
[Means for Solving the Problems]
The purpose is to provide a flow control member between the cylinder and the combustion chamber so that the combustible gas combusted in the combustion chamber expands and generates a stirring flow when flowing into the cylinder, and the cylinder is cooled by forced convection by the stirring flow. Can be achieved.
[0014]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, an embodiment of the present invention will be described with reference to FIG. The basic configuration is the same as the conventional example, and the combustion and scavenging operations are also the same as the conventional example.
[0015]
In the embodiment of FIG. 1, by installing a flow restricting member 17 between the combustion chamber 5 and the cylinder 4, the mixed gas is combusted and expanded in the combustion chamber 5 and flows into the cylinder 4. The flow is throttled and the flow velocity toward the lower side of the piston 10 is increased, whereby the stirring flow 18 is generated. Even after the piston 10 reaches the bottom dead center and the combustion gas is discharged from the exhaust hole 3, the stirring flow 18 remains in the cylinder 4 as an inertia flow and continues to stir. The heat transfer coefficient between the internal combustion gas and the inner wall of the cylinder 4 can be improved, and the combustion gas in the cylinder 4 can be efficiently cooled.
[0016]
FIG. 2 shows another embodiment of the present invention. A rotating vortex generating member 19 is provided between the combustion chamber 5 and the cylinder 4. A perspective view of the rotating vortex generating member 19 is shown in FIG. As in the above embodiment, the mixed gas is combusted and expanded in the combustion chamber 5 to generate a vortex-like stirring flow 20 along the inner wall of the cylinder 4 when flowing into the cylinder 4, and to continue a strong flow down to the cylinder 4. The heat transfer coefficient between the combustion gas in the cylinder 4 and the inner wall of the cylinder 4 is improved, and the cooling efficiency is increased.
[0017]
【The invention's effect】
According to the present invention, the forced convection in the cylinder can improve the cooling efficiency, can quickly cause the thermal vacuum, shorten the return time of the piston, and can repeatedly hit the nail.
[Brief description of the drawings]
FIG. 1 is a partial cross-sectional view showing an embodiment of the gas nailing machine of the present invention. FIG. 2 is a partial cross-sectional view showing another embodiment of the gas nailing machine of the present invention. FIG. 4 is a partial cross-sectional view showing an initial state of a conventional gas nailing machine. FIG. 5 is a partial cross-sectional view showing a state in which the gas nailing machine is pressed against wood from FIG. 6 is a partial cross-sectional view showing a state where the driving is advanced from FIG. 5 and the driving is completed. FIG.
4 is a cylinder, 5 is a combustion chamber, 6 is a fan, 7 is a gas cylinder, 8 is a motor, 9 is a spark plug, 10 is a piston, 17 is a flow restricting member, 19 is a rotating vortex generating member, and 18 and 20 are stirring flows. is there.

Claims (1)

A housing forming a main body, a combustion chamber supported in the housing and connected to a push lever below the main body and movable up and down; a fan provided in the combustion chamber and rotated by a motor outside the combustion chamber; and a combustion chamber A gas cylinder containing a combustible gas injected into the combustion chamber, a spark plug for igniting a mixture of combustible gas and air, a cylinder communicating with the combustion chamber below the combustion chamber and guiding the combustion chamber; The piston is guided by the cylinder and can be moved up and down, the exhaust hole provided in the lower side wall of the cylinder and the check valve provided outside the exhaust hole, and the nail supplied from the magazine is supported at the bottom of the housing. A gas nailer comprising a nail and a tail cover for guiding a piston,
A rotating vortex generating member is provided in the flow path between the combustion chamber and the cylinder, and the rotating vortex generating member makes the flow of the combustion gas after ignition in the cylinder a rotating vortex. And a gas nailing machine characterized in that the gas nailing machine is continued to the bottom of the cylinder .

Images