Hitachi Koki Co., Ltd.

Michio Wakabayashi

Yasuo Sasaki

Haruhiko Oouchi

Akira Uno

Takeshi Kamo

Yasuki Ohmori

Takeshi Matsuoka

Shoichi Hirai

Yoshitaka Akiba

Yoshihiro Nakano

Mitsuo Ogura

Shouichi Hirai

Hiroyasu Ishikawa

Takashi Mori

A pneumatically operated power tool includes an outer frame, a driving components, a pressure reduction valve, and a switching valve. The outer frame has a compressed air intake portion and defines therein a compressed air chamber. The driving components are disposed in the outer frame and are driven by a compressed air in the compressed air chamber. The pressure reduction valve defines a pressure receiving space and allows a compressed air to flow from the air intake portion to the compressed air chamber and to the pressure receiving space. The switching valve is movable between a first position where the compressed air flows from the compressed air intake portion to the pressure receiving space, and a second position where a communication between the compressed air intake portion and the pressure receiving space is blocked. The pressure reduction valve is configured to set a compressed air pressure in the compressed air chamber to a first pressure level if the switching valve is located at the first position and to set the compressed air pressure to a second pressure level lower than the first pressure level if the switching valve is located at the second position.

Pneumatically operated power tool having mechanism for changing compressed air pressure

A pneumatically operated screw driver ensuring a complete return of a piston to its top dead center. The screw driver has a compressed air return chamber for returning the piston to its top dead center by applying a compressed air in the return chamber to the piston. The piston includes a main piston and an auxiliary piston. The main piston is first reaches its bottom dead center, and then the auxiliary piston reaches its bottom dead center whereupon screw driving is terminated. Before the auxiliary piston reaches its bottom dead center, and after the main piston moves past a predetermined position, a compressed air is introduced into the return chamber. After the main piston reaches the bottom dead center, application of the compressed air pressure in the return chamber to the auxiliary piston is prevented.

Pneumatically operated screw driver

A pneumatically operated power tool such as a screw driver, a nail gun and an impact wrench those being driven by a pneumatic pressure. A pressure reduction valve is provided between a connector connected to a compressor and a compressed air chamber defined in an outer frame of the power tool for supplying a pressure lower than the pressure at the connector to the compressed air chamber. A passage section is provided independently of the pressure reduction valve and communicating the connector with the compressed air chamber. A valve member is disposed at the passage section for selectively applying compressed air from the connector to the compressed air chamber directly through the passage section.

A pneumatically operated screw driver ensuring a complete return of a piston to its top dead center. The screw driver has a compressed air return chamber for returning the piston to its top dead center by applying a compressed air in the return chamber to the piston. The piston includes a main piston and an auxiliary piston. The auxiliary piston includes a piston section and a flange section those being disposed in the main piston. The piston section is slidably movable relative to the main piston, and the flange section is axially spaced away from the piston section and radially spaced away from the main piston. After the main piston reaches its bottom dead center, the auxiliary piston further moves toward its bottom dead center. An air space chamber is provided between the piston section and the flange section and within the main piston.

A compact and light-weight pneumatically operated screw driver providing high speed screw fastening with high operability. A rotary member rotationally driven by a pneumatic motor includes a main rotary member made from a plastic material and a sliding segment fixed to the main rotary member. A rotation slide member is axially slidably movable relative to the rotary member and is rotatable together with the rotation of the rotary member. A shut-off section is provided on which the rotation slide member is rotationally seated when the rotation slide member is moved toward the shut-off section. The rotation slide member is made from an elastic material. A sleeve like piston having a seal ring in sliding contact with a cylinder is provided. The seal ring shuts off a supply of compressed air to the pneumatic motor only by the seating of the rotation slide member onto the shut-off section.

A pneumatically operated screw driver driven by a compressed air to drive screws into a workpiece. A drive bit connecting portion is rotated in a right-hand direction by rotation of a pneumatic motor and is formed with a right-handed threaded hole. A drive bit is formed at one end with a right-handed male threaded screw and at the other end with an engagement tip that engages with screws that are to be screwed into the workpiece. The drive bit is engaged with the drive bit connecting portion through threading engagement of the right-handed threaded hole and the righted-handed male threaded screw. For detaching the drive bit from the drive bit connecting portion, a rotation prevention mechanism prevents free rotation of the drive bit connecting portion. In this state, the engagement tip of the drive bit is engaged with an external tool. By rotating the external tool in a counterclockwise direction while preventing the rotation of a main body of the screw driver, the drive bit is disengaged from the drive bit connecting portion.

Pneumatically operated screw driver having drive bit attaching and detaching mechanism

Two guide members cooperatively constitute a chuck portion for holding a screw head. Opening and closing of the chuck portion is regulated depending on a mutual position between a machine body and a member into which a screw is driven. Guide pin portions of respective guide members engage with a stopper portion of a push lever until a screw is driven to a predetermined depth. The chuck potion tightly holds the screw head until a screw fastening operation is substantially finished, thereby suppressing the lifting of a machine body.

Screw fastening machine

A main valve and a manual operating valve cooperatively control the compressed air supplied to an air motor and a piston. The main valve is responsive to the compressed air supplied from the manual operating valve via an air passage. An orifice is provided in the air passage to reduce the speed of the compressed air supplied to the main valve so that the shift movement of the main valve is delayed when the manual operating valve is closed.

Pneumatically operable screw driver

An air motor has a rotor rotatable in response to the pressure of pressurized air. A cylindrical rotary member is connected to the air motor for causing a rotation in synchronism with the rotation of the rotor. A rotary slider is slidable in the axial direction along the inner cylindrical wall of the rotary member. A rotational force transmitting mechanism is provided for transmitting the rotation of the rotary member to the rotary slider. A shaft has one end fixed to the rotary slider and the other end equipped with a piston and a driver bit holder. The rotational and axial motion of the rotary slider is transmitted to a driver bit held in the driver bit holder. And, a cylinder guides the axial slide movement of the piston responsive to the pressure of pressurized air applied on a pressure-receiving surface of the piston.

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Hitachinaka, Japan

Michio Wakabayashi