초록 ▼

A pneumatic nail gun has a gun body having a main air housing; a cylinder fixed in the main air housing; a hitting piston slidably movable in the cylinder; a dish-shaped piston disposed at a top end portion of the cylinder; an upper slidable sleeve valve disposed at a top portion of an out periphera

A pneumatic nail gun has a gun body having a main air housing; a cylinder fixed in the main air housing; a hitting piston slidably movable in the cylinder; a dish-shaped piston disposed at a top end portion of the cylinder; an upper slidable sleeve valve disposed at a top portion of an out peripheral surface of the cylinder, which is driven to move upward by the high pressure air in the main air housing; and a lower slidable sleeve valve disposed at a lower portion of an outer peripheral surface of the cylinder, which is driven to move downward for guiding the high pressure air into the cylinder for upward deposition of the hitting piston when the upper slidable sleeve valve moves upward, and is driven to upward reposite when the hitting piston moves to its upper dead center.

대표청구항 ▼

What is claimed is: 1. A pneumatic nail gun comprising: a gun body, which has a main air housing collecting a compressed high pressure air with a constant pressure, and a trigger at one end of the main air housing driving the high pressure air to shoot a nail; a cylinder fixed in the main air housi

What is claimed is: 1. A pneumatic nail gun comprising: a gun body, which has a main air housing collecting a compressed high pressure air with a constant pressure, and a trigger at one end of the main air housing driving the high pressure air to shoot a nail; a cylinder fixed in the main air housing; a hitting piston slidably movable in the cylinder; a dish-shaped piston disposed at a top end portion of the cylinder, which is driven to move upward and guide the high pressure air into the cylinder for driving the hitting piston to rapidly move downward when the trigger is pressed, and is driven to move downward by the high pressure air in the main air house for closing the fluid communication into the cylinder when the trigger is released; an upper slidable sleeve valve disposed at a top portion of an outer peripheral surface of the cylinder, which is driven to move upward by the high pressure air in the main air housing when the trigger is released; a lower slidable sleeve valve disposed at a lower portion of an outer peripheral surface of the cylinder, which is driven to move downward for guiding the high pressure air into the cylinder for upward deposition of the hitting piston when the upper slidable sleeve valve moves upward, and is driven upward when the hitting piston moves to its upper dead center, the upper slidable sleeve valve being driven to downward reposite and closing the fluid communication to the lower slidable sleeve valve. 2. The pneumatic nail gun as claimed in claim 1, further comprising: a first air chamber formed between a top end of the dish-shaped piston and an inner peripheral surface of the gun body; which receives the high pressure air from the main air housing when the trigger is released, and exhausts the high pressure air when the trigger is pressed; a second air chamber formed between the dish-shaped piston and a top portion of an outer peripheral surface of the cylinder, which receives the high pressure air from the main air housing and drives the dish-shaped piston to move upward when the high-pressure air in the first air chamber is discharged. 3. The pneumatic nail gun as claimed in claim 2, wherein a top spring is disposed in the first air chamber, a sum of an elastic deformation force of the top spring and a pressure thrust of the high-pressure air in the first air chamber being larger than a pressure thrust of the high-pressure air in the second air chamber, and an elastic deformation force of the top spring being smaller than the pressure thrust of the high-pressure air in the second air chamber. 4. The pneumatic nail gun as claimed in claim 1, further comprising: a third air chamber formed among the cylinder, the upper slidable sleeve valve and the inner peripheral surface of the gun body, which fluidly communicates with the main air housing through a first through hole at the gun body, the high-pressure air therein driving the upper slidable sleeve valve to move downward when the dish-shaped piston moves downward and the hitting piston moves upward; a plurality of top vent holes formed at a top portion of the cylinder, which communicates the third air chamber and the cylinder, and guides the high pressure air to discharge into the cylinder when the upper sleeve valve and the dish-shaped piston move downward, and closes the fluid communication from the third air chamber to the cylinder when the upper slidable sleeve valve moves downward and the hitting piston moves upward; a fourth air chamber formed between an inner peripheral surface of the gun body and an outer peripheral surface of the upper slideable sleeve valve, which guides compressed high-pressure air in the main air housing to the fourth air chamber through at least one second through hole formed in the gun body, and drives the upper slidable sleeve valve to move upward when the high-pressure air in the third air chamber is discharged; and a plurality of bottom vent holes positioned at a bottom end portion of the cylinder, which guides the high-pressure air in the fourth air chamber into the cylinder to drive the hitting piston to upwardly move, when the lower sleeve valve moves downward. 5. The pneumatic nail gun as claimed in claim 4, wherein an intermediate spring is provided in the third air chamber, a sum of an elastic deformation force of the intermediate spring and a pressure thrust of the high-pressure air in the third air chamber being larger than a pressure thrust of the high-pressure air in the fourth air chamber, and the elastic deformation force of the intermediate spring being smaller than a pressure thrust of the high-pressure air in the fourth air chamber. 6. The pneumatic nail gun as claimed in claim 4, further comprising a step at a peripheral surface of an upper slidable sleeve valve, two air-tight rings assembled in an outer peripheral surface of the upper slidable sleeve valve, respectively, and an exhausting hole at the gun body between the two air-tight rings for decreasing a force acting area and a pressure thrust of a high-pressure air in the fourth air chamber. 7. The pneumatic nail gun as claimed in claim 4, further comprising a ring groove defined by the outer peripheral surface of the cylinder, the upper slidable sleeve valve, the lower slidable sleeve valve, and the gun body, which drives the lower slidable sleeve valve to move downward when the high pressure air in the fourth air chamber is guided therein. 8. The pneumatic nail gun as claimed in claim 4, further comprising a bottom spring used to push the lower slidable sleeve valve, which has an elastic deformation force less than a pressure thrust of the high-pressure air in the fourth air chamber guided from the fourth air chamber. 9. The pneumatic nail gun as claimed in claim 4, wherein the lower slidable sleeve valves has at least one upper step formed at a top portion thereof and a lower step formed at a lower portion thereof, the upper step having a force acting area larger than that of a force acting area of the lower step, the upper step being pushed by the high pressure air from the fourth air chamber, the lower step being pushed by the high pressure air from a main air passage formed in the gun body, which guides the high pressure air in the fourth air chamber. 10. The pneumatic nail gun as claimed in claim 9, wherein the lower slidable sleeve valve further provides two air-tight rings between its outer peripheral surface and the inner surface of the gun body, the lower step and an entrance of the main air passage being disposed between the two air-tight rings.