Patent Application
20150273569
1. Field of the Invention
The present invention relates to a barrel assembly, and more particularly to a barrel assembly for a rivet gun that prevents pneumatic cylinder from outputting high pressure air after an operation of pulling a rivet is completed, which reduces high pressure air consumption.
2. Description of Related Art
A conventional rivet gun is used to rivet two boards such that the boards are securely mounted together by rivets. A rivet has a cap and a core pin. The cap is T-shaped and has an enlarged end and a mounting end. The core pin is mounted longitudinally through and protrudes out of the cap and has two ends and a ball formed on one end and adjacent to the mounting end of the cap.
A conventional rivet gun comprises a barrel, a handle, a trigger, a pin collector and a pneumatic cylinder.
The barrel has a front end, a rear end and a vise assembly that may vise and pull a core pin of a rivet on the front end into the barrel. The handle is mounted perpendicularly on the barrel and has air passageways. The collector is a jar mounted on the rear end of the barrel to collect the ejected core pins. The pneumatic cylinder is mounted movably under the handle and capable of activating the vise assembly through pneumatic and hydraulic means. Furthermore, the pneumatic cylinder may be connected to a high-pressure air source such as an air bottle to implement the ejection of the core pin.
When the rivet gun is used to rivet two pieces such as boards or plates together, a rivet is mounted through the pieces. The enlarged end of the cap of the rivet abuts an inside piece, and the front end of the barrel of the rivet gun abuts the enlarged end. The trigger is pulled to activate the vise assembly to pull a core pin on the cap into the barrel. The ball on the core pin longitudinally compresses and radially expands the mounting end of the cap into T-shape so that the expanded mounting end hooks on an outside piece to complete the riveting process. Then, the air output by the high-pressure air source flows through the barrel from the front end to the rear end and sucks the broken core pin vised by the vise assembly backward into the collector.
Furthermore, a bypass hole is defined through the barrel and communicates with the air passageways. Therefore, when the trigger is pulled, the high pressure air in the pneumatic cylinder passes through air passageways and the bypass hole into the barrel and drives the vise assembly to move backward to pull the rivet. However, after the vise assembly completes the action of pulling the rivet and stays at a back position, the pneumatic cylinder continues outputting high pressure air through the bypass hole to external atmosphere, which meaninglessly consumes the high pressure air.
To overcome the shortcomings, the present invention provides a barrel assembly for a rivet gun to mitigate or obviate the aforementioned problems.
The main objective of the invention is to provide a barrel assembly for a rivet gun that prevents pneumatic cylinder from outputting high pressure air after an operation of pulling a rivet is completed, which reduces high pressure air consumption.
A barrel assembly for a rivet gun in accordance with the present invention has a tube body, a vising piston and a rear valve. The tube body has an assembling hole and a bypass hole. The vising piston is mounted slidably in the assembling hole of the tube body and has a piston head mounted slidably in the assembling hole of the tube body and having two O-rings mounted around the piston head at an interval, and a shaft formed on the piston head. The rear valve mounted on the rear opening of the assembling hole of the tube body. When the vising piston moves backward adjacent to the rear opening of the assembling hole of the tube body, the bypass hole of the tube body is located at the interval between the O-rings and is sealed by the 0-rings without consuming high pressure air from a pneumatic cylinder.
Other objectives, advantages and novel features of the invention will become more apparent from the following detailed description when taken in conjunction with the accompanying drawings.
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The vising piston 12 is mounted slidably in the assembling hole 110 of the tube body 11 and has a piston head 121, a shaft 125 and a through hole 120. The piston head 121 is mounted slidably in the assembling hole 110 of the tube body 11, hermitically contacts an inner surface of the assembling hole 110, has two O-rings 123, 124 and may further have two sealing rings 126, 127. The O-rings 123, 124 are mounted around the piston head 121 at an interval 122 and hermetically contact the inner surface of the assembling hole 110. The sealing rings 126, 127 are mounted around the piston head 121, hermetically contact the inner surface of the assembling hole 110, and seal and prevent the bypass hole 111 locating between the O-rings 123, 124 from communicating with external atmosphere. The shaft 125 is formed on and protrudes longitudinally from a front end of the piston head 121. The through hole 120 is defined longitudinally through the piston head 121 and the shaft 125.
The spring 13 is mounted in the assembling hole 110 of the tube body 11 and has a front end and a rear end. The front end presses against the piston head 121.
The connecting tube 14 is mounted securely on a rear end of the piston head 121 and has a central hole 141 defined longitudinally through the connecting tube and communicating with the through hole 120 of the vising piston 12.
The tool head 20 is mounted on the front opening 1101 of the assembling hole 110 of the tube body 11 and has a vise assembly mounted in the tool head 20 and connected to the vising piston 12. The vise assembly is capable of vising and pulling a section of a rivet into the rivet gun.
The rear valve 30 is mounted on the rear opening 1102 of the assembling hole 110 of the tube body 11, presses against the rear end of the spring 13 and has multiple components assembled together. Furthermore, the rear valve 30 slidably receives a rear end of the connecting tube 14.
When a user pulls the trigger 41 of the rivet gun, the vising piston 12 moves backward to pull a part of a rivet. The pneumatic cylinder 50 continuously outputs high pressures air into the barrel assembly 10 during a rivet-pulling stroke to eject a broken part of the rivet. When the vising piston 12 completely moves backward adjacent to the rear opening 1102 of the assembling hole 110 of the tube body 11 to a rivet-pulling position, as shown in
Even though numerous characteristics and advantages of the present invention have been set forth in the foregoing description, together with details of the structure and function of the invention, the disclosure is illustrative only. Changes may be made in the details, especially in matters of shape, size, and arrangement of parts within the principles of the invention to the full extent indicated by the broad general meaning of the terms in which the appended claims are expressed.
