Nail gun having a dry firing prevention device

Patent metadata

Field	Value
Publication number	US-9616561-B2
Application number	US-201414507164-A
Country	US
Kind code	B2
Filing date	Oct 6, 2014
Priority date	Oct 7, 2013
Publication date	Apr 11, 2017
Grant date	Apr 11, 2017

Abstract

A nail gun includes a body, a valve unit, a nail striking member and a detector. The body has a nail path, an air chamber, and an intake chamber guiding flow of air into the air chamber. The nail striking member is drivable by air pressure in the air chamber for striking a nail in the nail path. The valve unit is operable to switch between unblocking and blocking states to respectively permit and prevent fluid communication between the intake chamber and the air chamber. The detector is connected pivotally to the body, and is contactable with the valve unit such that, when there is no nail in the nail path, the valve unit is controlled by the detector to be in the blocking state.

First claim

What is claimed is:

1. A nail gun comprising:
a body having a nail path formed in a front end portion thereof, an air chamber, a main flowpath in fluid communication with said air chamber, and an air passage guiding flow of air into said main flowpath;
a nail striking member disposed in said nail path and drivable by air pressure in said air chamber to move along an X-axis for performing a nail striking operation;
a magazine connected with said body and including a magazine body adapted for receiving a plurality of nails, and a nail pushing unit movable between upper and lower limit positions and adapted for pushing and moving the nails into said nail path one at a time, said upper limit position being proximate to said nail path, said lower limit position being distal from said nail path;
a valve unit disposed in said air passage and cooperating with said body to divide said air passage into an intake chamber and an exhaust chamber that is adapted to be in fluid communication with the outside, said valve unit being in fluid communication with said main flowpath and said air passage and being operable to switch between an unblocking state, where fluid communication between said intake chamber and said air chamber is permitted and where fluid communication between said exhaust chamber and said air chamber is prevented, and a blocking state, where the fluid communication between said intake chamber and said air chamber is prevented and where the fluid communication between said exhaust chamber and said air chamber is permitted; and
a detector having a control portion, a detecting portion adapted to be contactable with one of said nail pushing unit and the nails, and an intermediate portion disposed between said control portion and said detecting portion and connected pivotally to said body, said control portion extending into said exhaust chamber and being contactable with said valve unit such that, when there is not any of the nails in said nail path, or when said nail pushing unit is moved to said upper limit position, said valve unit is controlled by said control portion of said detector to be in said blocking state.

2. The nail gun as claimed in claim 1 , wherein said detecting portion of said detector extends into said magazine, and is pushed by said nail pushing unit to rotate so as to press said control portion against a portion of said valve unit to thereby switch said valve unit to said blocking state when said nail pushing unit is moved to said upper limit position.

3. The nail gun as claimed in claim 1 , each of the nails having a nail body and a nail head connected to the nail body, wherein said nail gun further comprises a resilient member disposed between said control portion of said detector and said body for biasing said detector to rotate in a direction to move said control portion to contact said valve unit, said detecting portion of said detector being pushed by one of the nails to allow said detector to rotate in an opposite direction against biasing action of said resilient member to thereby remove said control portion from said valve unit so as to switch said valve unit to said unblocking state when the one of the nails is moved into said nail path.

4. The nail gun as claimed in claim 1 , wherein said valve unit includes a valve seat disposed fixedly in said air passage and having at least one through hole in fluid communication with said intake chamber of said air passage and said main flowpath, and a valve rod assembly movable in said valve seat to open and close said through hole.

5. The nail gun as claimed in claim 4 , wherein said control portion of said detector extends into said exhaust chamber, said valve seat having an auxiliary flowpath disposed between and in fluid communication with said through hole and said exhaust chamber such that, when said valve unit is in said blocking state, air in said air chamber can be discharged through said main flowpath, said through hole, and said exhaust chamber.

6. The nail gun as claimed in claim 5 , wherein said valve rod assembly includes a valve sleeve extending movably into said valve seat to form a first air gap therebetween, a valve rod extending movably into said valve sleeve and said valve seat to form a second air gap between said valve rod and said valve sleeve, and a third air gap between said valve rod and said valve seat, and a resilient member disposed between said valve rod and said valve sleeve for biasing said valve rod to contact said control portion of said detector, an end of said valve sleeve extending into said intake chamber and an end of said valve rod extending into said exhaust chamber such that, when said valve unit is in said unblocking state, fluid communication between said first air gap and said auxiliary flowpath is prevented, fluid communication between said intake chamber and said first air gap is permitted, and fluid communication between said intake chamber and said second air gap is permitted; and when said valve unit is in said blocking state, fluid communication between said intake chamber and said first air gap is prevented, fluid communication between said intake chamber and said second air gap is prevented, and fluid communication between said first air gap and said auxiliary flowpath is permitted.

7. The nail gun as claimed in claim 6 , wherein said valve sleeve has a first end surface, a second end surface opposite to said first end surface and facing toward an inner surface of said valve seat, and a hole extending through said first and second end surfaces and in fluid communication with said air passage, said second end surface having a surface area greater than that of said first end surface.

8. The nail gun as claimed in claim 7 , wherein said valve unit further includes first, second, and third seal members that are disposed between said valve seat and said valve sleeve, said first seal member being in sealing contact with said valve seat to define an air pressure space disposed between said second end surface and said valve seat and in fluid communication with said hole such that, when said valve unit is in said unblocking state, said second seal member is in sealing contact with said valve sleeve and said valve seat to prevent fluid communication between said first air gap and said auxiliary flowpath, and when said valve unit is in said blocking state, said third seal member is in sealing contact with said valve sleeve and said valve seat to prevent fluid communication between said intake chamber and said first air gap.

9. The nail gun as claimed in claim 7 , wherein said valve unit further includes a fourth seal member and a fifth seal member that are disposed between said valve rod and said valve sleeve such that, when said valve unit is in said unblocking state, said fourth seal member is in sealing contact with said valve rod and said valve seat to prevent fluid communication between said air pressure space and said exhaust chamber, and when said valve unit is in said blocking state, said fifth seal member is in sealing contact with said valve rod and said valve sleeve to prevent fluid communication between said air pressure space and said second air gap.

Assignees

• Basso Ind Corp

Inventors

• Liu An-Gi
• Liou Guey-Horng
• Lo Wen-Cheng

Classifications

• B25C1/04

  operated by fluid pressure {, e.g. by air pressure} · CPC title

• B25C1/008 Primary

  Safety devices · CPC title