Hitachi Koki Co., Ltd.

Akira Uno

Michio Wakabayashi

Yasuki Ohmori

Isamu Tanji

Yasuo Sasaki

Shoichi Hirai

Kaoru Ichikawa

Sueji Tachihara

Yasuyuki Hirano

Shinki Ohtsu

Takuji Torii

Yasunori Ogawa

Mitsuo Ogura

Haruhiko Oouchi

Toshihito Sakaba

Toshifumi Kubota

Hiroyasu Ishikawa

Yo Kawakami

Takeshi Kamo

Teruo Suzuki

Seki Moriguchi

Hiromu Utsumi

Tsunehisa Terayama

Tatsuo Innami

Katsuaki Tobita

Satoshi Kuno

Hiroki Orikasa

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 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

In a driving tool, an air tank is coupled via a pressure reducing valve to a rear end of a handle portion which is disposed substantially perpendicularly to an approximately cylindrical output section , and the air tank is configured by: a vertical portion which protrudes in the rear side of the handle section ; and a horizontal portion which extends in substantially parallel with the handle section , whereby the center of gravity of the whole tool is positioned in the vicinity of a gripping portion , so that the weight balance is improved and the dimensions are reduced.

Driving tool

A nailing machine is provided with a second accumulator chamber,capable of accumulating compressed air having a pressure higher than air pressure usable by a machine body, an air intake,connectable to an air compressor via an air hose or the like, a valve,for control of the communication between the second accumulator chamber,and the air intake,and a pressure reducing valve,for reducing the compressed air pressure in the second accumulator chamber,and supplying the pressure-reduced compressed air into a first accumulator chamber

Nailing 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.

A nose 2 has a recessed portion 4 engageable with the front end of a magazine 3. A through-hole 12 is provided on each side wall of the recessed portion 4 of nose 2. The front end of magazine 3 is formed into a protruding portion 6 just fitting to or coupled into the recessed-portion 4 of nose 2. A through-hole 13 is opened across the protruding portion 6 of magazine 3 so that through-hole 13 meets through-holes 12 opened on the side walls of the recessed portion 4 when the magazine 3 is completely engaged with the nose 2. A pin 16 is inserted into the through-holes 12 and 13 to fix magazine 3 in the recessed portion 4 of nose 2. A resilient member 15 is provided between pin 16 and through-hole 13.

Staple tacker with a striking nose and a staple magazine

A pneumatically operated screw driver having a pneumatically operated rotor rotatably supported in an outer frame. The rotor is only rotatable about its axis. A moving unit is slidably disposed within the rotor. The moving unit has an upper piston and is axially movable upon application of pneumatic pressure to the upper piston. The moving unit is also rotatable about its axis because of spline connection with the rotor. A valve is disposed for selectively applying the pneumatic pressure to the piston and to the rotor. Upon application of the pneumatic pressure, the moving unit is moved downwardly, and the pneumatic pressure is then introduced into the rotor for rotating the same. The rotation of the rotor is transmitted to the moving unit. The valve closes a fluid passage directing to the piston and to the rotor when the moving unit has the lowermost position.

A combustion gas powered tool includes a member defining a part of cylindrical combustion chamber having an axis. A piston is movable in a direction along the axis of the combustion chamber. The piston defines the combustion chamber in conjunction with the member. A mixture of air and fuel is generated in the combustion chamber. The air-fuel mixture in the combustion chamber is burned to drive the piston. An orifice grille extends in the combustion chamber, and is parallel to the axis of the combustion chamber.

Combustion gas powered tool

A pneumatic fastener driving tool includes a main valve operable to cause compressed air to be alternately introduced into and discharged from the upper piston chamber, a first passage leading the compressed air into the main valve chamber, a repeat valve disposed in the first passage for opening and closing the same, and a second passage extending between the lower piston chamber and a repeat valve chamber in which the repeat valve is reciprocably received. With this construction, the repeat valve is reciprocally movable in response to a change of pressure in the lower piston chamber to cause the main valve to reciprocate, thereby reciprocating the piston repeatedly. Since the reciprocating fastener driving movement of the piston is directly related to the reciprocating movement of the repeat valve, the fastener driving work can be achieved reliably without causing any operational failure such as a non-load striking.

Pneumatic fastener driving tool

Pneumatic nailer

A pneumatic fastener driving tool including a start valve adapted to be open for start a fastener driving operation by pneumatically driving a driving rod forwardly, and a vent hole for connecting to start valve to atmospheric air to let compressed air escape to atmosphere when compressed air is accidentally supplied through the start valve after one cycle of fastener driving operation is completed due to bouncing of the piston, for example.

A fastener driving tool such as a pneumatic nailing machine drives a fastener into a workpiece under a fluid pressure supplied into an upper chamber in a cylinder and applied to a piston reciprocally movably disposed in the cylinder. When the fastener being driven is stopped in a power stroke of the piston due to a pressure shortage, the fluid flows from the upper chamber into a lower chamber in the cylinder to make the pressure in the lower chamber equal to or higher than the pressure in the upper chamber. No reactive forces are thus applied by the high pressure in the upper chamber to the fastener driving tool, and the fastener driving tool is prevented from being repelled back when the fastener is stopped. The fastener can then be driven home into the workpiece in successive power strokes of the piston.

Fastener driving tool

A power driven percussion tool is provided with a rotatable magazine block formed with a plurality of bores about the axis of rotation of the magazine block and is loaded with fasteners such as rivets or nails respectively retained in the bores. When the magazine block is stepwise rotated about its axis the bores are successively brought into alignment with the direction in which the fastener can be driven by a reciprocating hammer. The percussion tool is further provided with safety means for disabling the tool when the tool is not in use or being re-loaded with fasteners.

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Hitachioota, Japan

Akira Uno