A blind-rivet gun includes a gun header, a cylinder, a piston, and an air saving device. The cylinder is separated from the gun header. The piston and an inner surface of the cylinder form a seal to divide the cylinder into a first air chamber and a second air chamber. The air saving device includes a switch circuit. The switch circuit turns on a first connection between the air inlet pipe and the first air outlet pipe or turns on a second connection between the air inlet pipe, the second air outlet pipe and the third air outlet pipe. The piston slides in the cylinder to generate inner high pressure by alternatively supplying high pressure air to the first air chamber or the second air chamber. The blind-rivet is pulled in and is pushed out of the blind-rivet ejecting pipe by the inner high pressure.

BACKGROUND

1. Technical Field

The present disclosure relates to mechanical tools, and particularly to a blind rivet gun.

2. Description of Related Art

A blind-rivet gun for setting blind-rivets is well known and is generally used in the following way. A blind-rivet having an internal thread in the inner periphery of a flanged sleeve is inserted and is fitted in, for example, mounting holes in two panels connected to each other, and a screw mandrel of the blind-rivet gun is threadedly connected to blind-rivets. The blind-rivet gun is often equipped with a barometric pressure apparatus, which provides barometric pressure. While the barometric pressure apparatus presses the flanged sleeve of the blind-rivet to the lateral sides of the panel mounting holes, the screw mandrel is retracted toward the inner side of the gun body to outwardly expand and deform the flanged sleeve. Thus, the two panels are secured to each other as pressed and held between the deformed sleeve and the flange. However, the barometric pressure apparatus is often combined with the blind-rivet gun and always turned on to provide barometric pressure, which wastes high pressure air.

Therefore, there is room for improvement within the art.

DETAILED DESCRIPTION

Referring toFIG. 1, a blind-rivet gun in accordance with an embodiment, includes a cylinder10, a gun header20and an air saving device30.

The cylinder10is hollow and contains a reciprocating piston14. The cylinder10includes a first air inlet opening11and a second air inlet opening12on one side and an air hole13on a top. The first air inlet opening11and the second air inlet opening12are connected to an inner space of the cylinder10. The piston14includes a piston header141and a piston rod142connected to the piston header141. The size of the piston header141is about the same as that of a cross section of the inner space of the cylinder10.

The piston header141forms a seal with the inner surface of the cylinder10, dividing the inner space of the cylinder10into a first air chamber15and a second air chamber16. The piston rod142can slide in the air hole13of the cylinder10. The first air chamber15is connected to the first air inlet opening11. The second air chamber16is connected to the second air inlet opening12. The cylinder10is connected to the gun header20via an oil pipe40. The oil pipe40contains oil substance41therein. The piston header141can slide in the first air chamber15and the second air chamber16to adjust a barometric pressure in the gun header20by the oil substance41.

The gun header20includes a blind-rivet ejecting pipe21. A clamping member22is mounted on the blind-rivet ejecting pipe21for holding a blind-rivet50. A blind-rivet inlet opening211is defined at a first end of the blind-rivet ejecting pipe21. A blind-rivet outlet opening212is defined at a second end of the blind-rivet ejecting pipe21. A spring23is fixed in the gun header20between the clamping member22and the blind-rivet outlet opening212. A third air inlet opening24is defined on the blind-rivet ejecting pipe21for injecting high pressure air from a barometric pressure apparatus (not shown).

The blind-rivet50includes a blind-rivet header51and a blind-rivet tail52. The gun header20can eject the blind-rivet50.

The air saving device30includes a switch circuit31, an air inlet pipe32, a first air outlet pipe33, a second air outlet pipe34and a third air outlet pipe35. The air inlet pipe32is connected to the barometric pressure apparatus for receiving high pressure air. The first air outlet pipe33is connected to the first air chamber15via the first air inlet opening11. The second air outlet pipe34is connected to the second air chamber16via the second air inlet opening12. The third air inlet opening24is connected to the blind-rivet ejecting pipe21. The second air outlet pipe34is connected to the third air outlet pipe35. The switch circuit31includes a first valve311and a second valve312. The first valve311includes a first valve anode and a first valve cathode. The second valve312includes a second valve anode and a second valve cathode. The first valve anode is electrically connected to a +24 volts working voltage via a first switch313. The second valve anode is electrically connected to the +24 volts working voltage via a second switch314. The first valve cathode and the second valve cathode are grounded.

When the second switch314is closed, the switch circuit31cuts off high pressure air from the barometric pressure apparatus; when the second switch314is opened, and the switch circuit31turns on high pressure air from the barometric pressure apparatus. When the second switch314is opened and if the first switch313is closed, the switch circuit31turns on the connection between the air inlet pipe32and the first air outlet pipe33; the switch circuit31cuts off the connection between the air inlet pipe32, the second air outlet pipe34and the third air outlet pipe35(as shown inFIG. 2). When the second switch314and the first switch313are opened, the switch circuit31turns on the connection between the air inlet pipe32, the second air outlet pipe34and the third air outlet pipe35; and the switch circuit31cuts off the connection between the air inlet pipe32and the first air outlet pipe33(as shown inFIG. 3).

A first button313′ and a second button314′ are disposed on a connection portion (not labeled) between the gun header20and the oil pipe40. The first button313′ controls the first switch313to be closed or opened. The second button314′ controls the second switch314to be closed or opened. When the first button313′ is pressed, the first switch313is closed; when the first button313′ is released, the first switch313is opened. When the second button314′ is pressed, the second switch314is opened; when the second button314′ is released, the second switch314is closed.

Referring toFIG. 1toFIG. 3, when using the blind-rivet gun, the second button314′ is pressed to open the second switch314, high pressure air from the barometric pressure apparatus is provided to the switch circuit31. The switch circuit31turns on the connection between the air inlet pipe32, the second air outlet pipe34, and the third air outlet pipe35, and cuts off the connection between the air inlet pipe32and the first air outlet pipe33. High pressure air from the barometric pressure apparatus is supplied in the blind-rivet ejecting pipe21via the third air outlet pipe35and the third air inlet opening24. The blind-rivet50is pulled in the blind-rivet ejecting pipe21and fixed on the clamping member22under the pressure of high pressure air.

The first button313′ is pressed to close the first switch313. The switch circuit31turns on the connection between the air inlet pipe32and the first air outlet pipe33, and cuts off the connection between the air inlet pipe32, the second air outlet pipe34and the third air outlet pipe35. High pressure air from the barometric pressure apparatus is supplied in the first air chamber15via the first air outlet pipe33and the first air inlet opening11. The piston14moves toward the top of the cylinder10. The piston rod142presses the oil substance41to move in the oil pipe40and enter the gun header20. The oil substance41presses the clamping member22to slide in the gun header20along a first direction. The clamping member22clips the blind-rivet50to move together in the gun header20along the first direction under the pressure of the oil substance41. The spring23is elastically deformed. The blind-rivet tail52is stopped by the blind-rivet inlet opening211and is separated from the blind-rivet header51.

The first button313′ is then released to open the first switch313. The switch circuit31turns on the connection between the air inlet pipe32, the second air outlet pipe34and the third air outlet pipe35, and cuts off the connection between the air inlet pipe32and the first air outlet pipe33. High pressure air from the barometric pressure apparatus is supplied in the second air chamber16via the second air outlet pipe34and the second air inlet opening12. High pressure air from the barometric pressure apparatus is also supplied in the blind-rivet ejecting pipe21via the third air outlet pipe35and the third air inlet opening24.

The piston14moves toward a bottom of the cylinder10. The piston rod142releases the oil substance41in the gun header20. The plurality of oil substance41enters the oil pipe40and releases the clamping member22. The clamping member22releases the blind-rivet header51. The blind-rivet header51is pushed out of the blind-rivet outlet opening212by the pressure of high pressure air in the blind-rivet ejecting pipe21. The clamping member22slides in the gun header20along a second direction opposite to the first direction. The spring23is elastically returned. The clamping member22returns to an original position in the gun header20.

In one embodiment, high pressure air from the barometric pressure apparatus is only supplied in the blind-rivet ejecting pipe21during the process that the blind-rivet50is pulled in or pushed out of the blind-rivet ejecting pipe21. However, high pressure air from the barometric pressure apparatus is not supplied in the blind-rivet ejecting pipe21during the process that the blind-rivet50moves in the blind-rivet ejecting pipe21. Therefore, high pressure air is retained.