[54] PNEUMATIC TOOL
[75] Inventors: Kenji Mukoyama; Yukiyasu Okouchi;
Masaki Sakuragi; Junichi Iwakami,
all of Anjo, Japan
[73] Assignee: Makita Corporation, Anjo, Japan
[21] Appl. No.: 09/309,888
[22] Filed: May 11, 1999
[30] Foreign Application Priority Data
May 11, 1998 [JP] Japan 10-127778
[51] Int. CI.7 B25C 1/04
[52] U.S. CI 227/130; 227/8; 227/142
[58] Field of Search 227/130, 8, 113,
227/142, 119
[56] References Cited
U.S. PATENT DOCUMENTS 3,438,449 4/1969 Smith .
5,131,579 7/1992 Okushima et al 227/8
5,441,192 8/1995 Sugita et al 227/130
5,495,973 3/1996 Ishizawa et al 227/113
5,671,880 9/1997 Ronconi 227/130
5,715,982 2/1998 Adachi 227/142
FOREIGN PATENT DOCUMENTS
4 812913 4/1973 Japan .
A pneumatic tool, such as a nailer, includes a housing, a cylinder disposed within the housing, and a piston slidably movable within the cylinder. The piston has a driver for driving fasteners, such as nails. An upper piston chamber and a lower piston chamber are defined within the cylinder on an upper side and a lower side of the piston, respectively. A control device is provided for controlling the supply of compressed air from a compressed air supply device to the upper piston chamber and to the lower piston chamber to drive the fasteners into a workpiece. The control device includes a variable pressure chamber and a valve. The variable pressure chamber is always connected to the compressed air supply device. The valve is operable to connect and disconnect the variable pressure chamber and the lower piston chamber in response to the position of the piston relative to the cylinder. A device is provided to maintain a predetermined volume in the variable pressure chamber, irrespective of the operation of the control device.
12 Claims, 18 Drawing Sheets
