This application claims priority of Taiwanese Patent Application No. 099131815, filed on Sep. 20, 2010, the disclosure of which is herein incorporated by reference.
1. Field of the Invention
This invention relates to a pneumatic nailing machine, more particularly to a pneumatic nailing machine having a winding air channel for exhaust.
2. Description of the Related Art
Referring to
Since the compressed air exhausted from the striking cylinder 11 flows along a substantially axial path at a very high rate, a loud noise is generated even though the throttle holes 143, through which the exhausted compressed air flows, are provided.
An object of the present invention is to provide a pneumatic nailing machine which has a winding air channel for exhaust so as to attenuate noise generated as a result of flow of exhaust air.
According to this invention, the pneumatic nailing machine includes a main housing extending along an axis to terminate at front and rear ends. A mounting shell extends axially from the rear end. A rear cover shell extends axially from the mounting shell to terminate at a cover wall, and defines a head valve zone. A striking cylinder includes a front cylinder portion which is disposed in the main housing to cooperatively define an air chamber that is supplied with compressed air, and a rear cylinder portion which extends axially from the front cylinder portion to terminate at an access opening that confronts the cover wall. A piston and driver assembly is disposed in the striking cylinder and moved relative to the striking cylinder along the axis so as to drive a fastener when the compressed air is supplied to the striking cylinder. A first gate member is disposed between the rear cylinder portion and the mounting shell, and defines an inlet valve opening that is upstream of the access opening and downstream of the air chamber in terms of an air-supplying route. A second gate member is disposed between the rear cylinder portion and the rear cover shell, and defines an outlet valve opening that is upstream of the head valve zone and downstream of the access opening in terms of an air-exhausting route. A valve member includes inlet-side and outlet-side valve regions, and is movable between an air-supplying position, where the outlet-side valve region closes the outlet valve opening to interrupt fluid communication between the access opening and the head valve zone while the inlet-side valve region opens the inlet valve opening to establish fluid communication between the access opening and the air chamber, and an air-exhausting position, where the inlet-side valve region closes the inlet valve opening to interrupt the fluid communication between the access opening and the air chamber while the outlet-side valve region opens the outlet valve opening to establish the fluid communication between the access opening and the head valve zone. A winding air channel has an intake port which is formed in the rear cover shell, and which is disposed downstream of the head valve zone, an outflow port which is formed in and radially extending out of the mounting shell, and which is angularly displaced from the intake port about the axis, and a channel body which extends radially from the intake port, axially into the mounting shell, and toward the outflow port to form a plurality of mounting-shell-side consecutive channel segments that are upstream of the outflow port, each having a first circumferentially extending subsegment. Thus, the compressed air exhausted from the striking cylinder can expand in the air channel so that the flow rate of the compressed air is reduced, thereby efficiently attenuating noise generated as a result of the compressed air flow.
Other features and advantages of the present invention will become apparent in the following detailed description of the preferred embodiment of the invention, with reference to the accompanying drawings, in which:
Referring to
A valve member 32 includes inlet-side and outlet-side valve regions 322, 323, and is movable between an air-supplying position (
This embodiment further comprises a winding air channel 4 provided in the mounting shell 22 and the rear cover shell 23 for exhausting the compressed air in the striking cylinder 31.
Specifically, as shown in
Hence, the winding air channel 4 has an outflow port 27 which is formed in and extends radially out of the surrounding shell body 221, and a channel body which includes a plurality of mounting-shell-side consecutive channel segments 43 formed in the circumferentially extending trench 222. Each of the channel segments 43 has a first circumferentially extending subsegment 431 and two consecutive first axially extending subsegments 432 which are interconnected by the first circumferentially extending subsegment 431. The circumferentially extending trench 222 extends axially so as to accommodate the orientation of the first axially extending subsegments 432, i.e., a forward-and-rearward direction. Further, the surrounding shell body 221 has a plurality of first baffle ribs 223 which are disposed in the circumferential extending trench 222, and which are angularly displaced from each other about the axis (X). Each of the first baffle ribs 223 is disposed forwardly from the surrounding abutted surface 25. Furthermore, the surrounding shell body 221 has a plurality of first baffle posts 224 which are alternately arranged with and angularly displaced from the first baffle ribs 223 and which respectively define a plurality of passages 45, 46, each communicating two adjacent ones of the first axially extending subsegments 432 of two consecutive ones of the mounting-shell-side consecutive channel segments 43.
The rear cover shell 23 has a tubular wall 233 which extends axially from a periphery of the cover wall 231 to terminate at a surrounding abutting surface 26 that is in abutting engagement with the surrounding abutted surface 25 of the mounting shell 22, and which extends circumferentially. The tubular wall 233 has a circumferentially extending groove 234.
The winding air channel 4 further has an intake port 48 which is formed in the rear cover shell 23 to be downstream of the head valve zone 232 and upstream of the circumferentially extending groove 234, and which is angularly displaced from the outflow port 27 about the axis (X). Preferably, the intake port 48 and the outflow port 27 are formed at two diametrically opposite sides with respect to the axis (X). The channel body further includes a plurality of cover-shell-side consecutive channel segments 44 formed in the circumferentially extending groove 234. Each of the cover-shell-side consecutive channel segments 44 has a second circumferentially extending subsegment 441 and two second axially extending subsegments 442 interconnected by the second circumferentially extending subsegment 441. The circumferentially extending groove 234 extends axially so as to accommodate the orientation of the second axially extending subsegments 442, i.e., the forward-and-rearward direction, and is in spatial communication with the circumferentially extending trench 222 to thereby expand axially the winding air channel 4 to the tubular wall 233. Further, the tubular wall 233 has a plurality of second baffle ribs 235 which are disposed in the circumferentially extending groove 222, and which are angularly displaced from each other about the axis (X). Each of the second baffle ribs 235 is disposed rearwardly from the surrounding abutting surface 26. Thus, the channel body extends radially from the intake port 48, axially into the mounting shell 22, and circumferentially toward the outflow port 27
With such winding air channel 4, the compressed air in the striking cylinder 31 flows alternately along the mounting-shell-side consecutive channel segments 43 and the cover-shell-side consecutive channel segments 44 which are alternately arranged and angularly displaced from each other, thereby resulting in expansion of the compressed air in the air channel 4 so as to reduce the flow rate of the compressed air, thereby efficiently attenuating noise generated as a result of the compressed air flow. Moreover, since the winding air channel 4 is provided in an interior space of the mounting shell 22 and the rear cover shell 23 without the need to enlarge the volume of the nailing machine, and made by superimpose the rear cover shell 23 and the mounting shell 22 upon the rear end 211 of the main housing 21, the nailing machine may be made compact and is readily assembled.
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 interpretations and equivalent arrangements.
Number | Date | Country | Kind |
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99131815 A | Sep 2010 | TW | national |
Number | Name | Date | Kind |
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4401251 | Nikolich | Aug 1983 | A |
4509669 | Elliesen | Apr 1985 | A |
4667572 | Elliesen | May 1987 | A |
5878936 | Adachi et al. | Mar 1999 | A |
Number | Date | Country | |
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20120067935 A1 | Mar 2012 | US |