This application claims priority to Chinese Application Nos. 201320216447.3 and 201310147884.9, filed on Apr. 25, 2013.
1. Field of the Invention
The present invention relates to a combustion nailing tool, more particularly to a pneumatic cylinder module for a combustion nailing tool.
2. Description of the Related Art
A conventional nailing tool usually includes a cylinder body defining an axis, a cylinder head, a plastic housing connecting the cylinder body to the cylinder head along the axis, and a sleeve surrounding the cylinder body and the cylinder head to define a combustion chamber thereamong.
However, the plastic housing is subjected to severe impact attributed to explosion during use of the nailing tool and may therefore deform. Consequently, the cylinder body and the cylinder head that are connected to the deformed plastic housing would offset from the original axis, thus disfavoring accuracy of the nailing tool.
Therefore, an object of the present invention is to provide a pneumatic cylinder module for a combustion nailing tool capable of alleviating the aforesaid drawback.
According to the present invention, the pneumatic cylinder module comprises a cylinder unit, a cylinder head and a sleeve. The cylinder unit includes a tubular main body, a plurality of connecting ribs, and a positioning ring. The tubular main body defines a central axis. The connecting ribs are connected to a rear end of the main body at respective angularly spaced-apart positions with respect to the central axis, and extend in a longitudinal direction substantially parallel to the central axis. The positioning ring is coaxial with the main body and is connected to the connecting ribs opposite to the main body. The cylinder head is mounted to and covers the positioning ring opposite to the connecting ribs. The sleeve is sleeved around the cylinder unit, surrounds the connecting ribs, cooperates with the cylinder bead and the main body to define a combustion chamber thereamong, and is movable relative to the cylinder unit along the central axis between a closed position, where the sleeve seals the combustion chamber, and an open position, where the sleeve allows access to the combustion chamber.
Other features and advantages of the present invention will become apparent in the following detailed description of the preferred embodiment with reference to the accompanying drawings, of which;
Referring to
As shown in
The positioning ring 13 has a peripheral surface 130 formed with a second annular slot 131, and a rear side surface 135. The second annular slot 131 surrounds the central axis (X). The rear side surface 135 of the positioning ring 13 faces the cylinder head 2, and is formed with a first engaging member 132 configured as a recess in this embodiment. The positioning ring 13 is formed with a plurality or threaded holes 133 extending in the longitudinal direction through the positioning rings 13 into the connecting ribs 12, respectively. The cylinder unit 1 further includes two O-rings 14 (see
Further referring to
Further referring to
The sleeve 3 includes a tube body 31, a reinforcing flange 311, a plurality of limiting arms 32 and a guiding aria 33. The tube body 31 surrounds the connecting ribs 12. The limiting arms 32 extend from a rear edge of the tube body 31 in the longitudinal direction toward the cylinder head 2, surround the cylinder head 2, and are staggered with the protrusions 22 so as to confine movement of the sleeve 3 relative to the cylinder head 2 in the longitudinal direction. The reinforcing flange 311 extends radially and outwardly from the tube body 31, and corresponds to the positioning ring 13 in position when the sleeve 3 is at the closed position. The guiding arm 33 extends from the tube body 31 in the longitudinal direction, and slidably engages the guiding groove 112 formed in the main body 11 of the cylinder unit 1 so as to guide the sleeve 3 to move between the open and closed positions along the central axis (X).
The heat insulating housing 4 includes a housing body 41 and a cover 42. The housing body 41 receives the cylinder unit 1, the cylinder head 2 and the sleeve 3 therein. The cover 42 is disposed at and covers an open end of the housing body 41 that is adjacent to the cylinder head 2. For example, the cover 42 of the heat insulating housing 4 is stably connected to the cylinder head 2 using a plurality of threaded screws, which extend through the cover 42 respectively into the threaded holes 221.
When the sleeve 3 is at the close position and the combustion chamber 10 is sealed by the O-rings 14, flammable gas (such as methane) is introduced into the combustion chamber 10, and then a spark plug 51 ignites mixture of the flammable gas and air in the combustion chamber 10 to generate an explosion, driving a firing pin 52 to fire a nail (not shown). Thereafter, the sleeve 3 is moved to the open position to discharge exhaust gas and to introduce fresh air into the combustion chamber 10 for subsequent use.
To sum up, since the main body 11, the connecting ribs 12 and the positioning ring 13 are integrally formed, reaction force attributed to the explosion may slightly stretch the connecting ribs 12 and may be absorbed thereby, alleviating direct impact on and deformation of the heat insulating housing 4. Accordingly, service life of the pneumatic cylinder module of the present invention may be increased. Further, the configuration of the guiding arm 33 and the guiding groove 112 and the configuration of the limiting arm 32 staggered with the protrusions 22 confine axial movement of the sleeve 3 relative to the cylinder unit 1 and the cylinder head 2 in the longitudinal direction. Thus, a relatively good accuracy of the nailing tool can be achieved.
While the present invention has been described in connection with what is considered the most practical and preferred embodiment, it is understood that this invention is not limited to the disclosed embodiment but is intended to cover various arrangements included within the spirit and scope of the broadest interpretation so as to encompass ail such modifications and equivalent arrangements.
Number | Date | Country | Kind |
---|---|---|---|
201310147884.9 | Apr 2013 | CN | national |
201320216447.3 | Apr 2013 | CN | national |