Patents by Inventor Yoshinori Ishizawa

Yoshinori Ishizawa has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).

  • Patent number: 7322505
    Abstract: A pneumatically powered nail gun having a duster mechanism which is also pneumatically powered with the same pneumatic source. The nail gun includes a main body having a lower end and defines therein a compressed air chamber. A cylinder piston arrangement is disposed in the main body, and the compressed air is selectively applied to the piston for moving a driver blade connected to the piston to drive a nail. The duster mechanism includes a duster nozzle provided at the main body for ejecting a compressed air therethrough. A pressure release valve is disposed at an air passage extending between the duster nozzle and the compressed air chamber for selectively shutting off a fluid communication therebetween. A pressure regulating section is disposed at the air passage for providing a compressed air passing through the duster nozzle at a pressure lower than that in the compressed air chamber.
    Type: Grant
    Filed: August 2, 2004
    Date of Patent: January 29, 2008
    Assignee: Hitachi Koki Co., Ltd.
    Inventors: Yoshinori Ishizawa, Yoshihiro Nakano
  • Patent number: 7299959
    Abstract: A magazine cover is integrally molded with a return-preventing claw part to be engaged with a fastener loaded into a guide part. The return-preventing claw part is so constructed as to include: a return preventing surface that abuts against the fastener to prevent the fastener from moving to a loading port; and a support portion that always makes the return preventing surface abut against the fastener, thereby being deformed, to support the return preventing surface such that the return preventing surface can be retracted to a position where the return preventing surface does not abut against the fastener.
    Type: Grant
    Filed: July 12, 2005
    Date of Patent: November 27, 2007
    Assignee: Hitachi Koki Co., Ltd.
    Inventors: Yoshinori Ishizawa, Hiroki Kitagawa, Masashi Nishida
  • Patent number: 7243831
    Abstract: A fastener driving tool includes: a driver blade adapted to drive nails joined to one another into an object in order; a nose adapted to guide the driver blade and nails; and a guide surface of a projection adapted to guide a head portion of a first nail struck out into an exit hole of the nose so that the second nail is not exposed to the exit hole. The guide surface of the projection is formed to a shape identical with that of the head portions of the nails.
    Type: Grant
    Filed: July 14, 2005
    Date of Patent: July 17, 2007
    Assignee: Hitachi Koki Co., Ltd.
    Inventors: Yoshinori Ishizawa, Hiroki Kitagawa, Masashi Nishida
  • Publication number: 20070113733
    Abstract: A fastener driving tool includes a frame defining therein an accumulator that accumulates compressed air, a cylinder, a piston movable between a top dead center and a bottom dead center, a main valve section having a main valve movable between a top dead center and a bottom dead center to alternately open and block fluid communication between a piston upper chamber and the accumulator, a trigger valve section having a plunger movable between a top dead center and a bottom dead center so as to alternately open and block fluid communication from the accumulator to a main valve chamber, and fluid communication from the main valve chamber to atmosphere, and a trigger adapted to press the plunger when operated by a user. The piston moves from the top dead center to the bottom dead center within 11.3 msec when the plunger is pressed.
    Type: Application
    Filed: December 21, 2006
    Publication date: May 24, 2007
    Inventors: Yoshiichi Komazaki, Yoshinori Ishizawa, Masashi Nishida
  • Patent number: 7156012
    Abstract: A pneumatically operated fastener driving tool capable of reducing a time period from operation timing of a trigger to downward movement of a driver blade for fastener driving, and reducing a time period from the release timing of the trigger to a timing at which respective components are returned to their initial positions for a subsequent nail driving. As components a main valve and a trigger valve is provided. The main valve is movable within a main valve chamber connected to a main valve control channel. The trigger valve selectively provides fluid communication between the accumulator and a main valve chamber through the main valve control channel and between the main valve chamber and the atmosphere through the main valve control channel. A ratio of cross-sectional area of the main valve control channel to an internal volume of the main valve chamber is defined to a specified ratio.
    Type: Grant
    Filed: January 21, 2005
    Date of Patent: January 2, 2007
    Assignee: Hitachi Koki Co., Ltd.
    Inventors: Yoshiichi Komazaki, Yoshinori Ishizawa, Masashi Nishida
  • Patent number: 7014089
    Abstract: A plunger is shiftable in response to a trigger operation by a user. A valve piston has a valve piston chamber therein for slidably accommodating the plunger and an axial bore into which the plunger is inserted. An air passage connects the valve piston chamber to an atmosphere via a clearance between the plunger and the axial bore of the valve piston. A seal member is provided to seal the clearance between the plunger and the axial bore of the valve piston. And, a relief passage is formed on at least one of the plunger and the axial bore of the valve piston to open the air passage, thereby allowing compressed air to exit from the valve piston chamber to the atmosphere under a condition where the plunger is engaged with the axial bore of the valve piston.
    Type: Grant
    Filed: April 15, 2004
    Date of Patent: March 21, 2006
    Assignee: Hitachi Koki Co., Ltd.
    Inventors: Yoshinori Ishizawa, Masanori Aoki, Hiroki Kitagawa
  • Publication number: 20060016843
    Abstract: A clearance is set between a nail feeder and an outer profile portion so that the nail feeder can turn. A pin as a first restriction member that inhibits movement of the nail feeder to an ejection portion by engaging with the nail feeder and can release the engagement with the rotation of the nail feeder is provided to the outer profile portion. The position at which the nail feeder and a spring engage is set in deviation from the position at which the nail feeder and the pin engage, in a reciprocating direction of the nail feeder and in a vertical direction.
    Type: Application
    Filed: July 8, 2005
    Publication date: January 26, 2006
    Inventors: Yoshinori Ishizawa, Hiroki Kitagawa, Masashi Nishida
  • Publication number: 20060016844
    Abstract: A top cover is made of a metal and constituted to provide substantially a bowl-like shape extended from an upper side of an exhaust cover in a side direction. Further, a damping member including an elastic member is provided between the top cover and the exhaust cover. Further, an expansion chamber constituting a space of communicating with an exhaust path and the exhaust port for communicating the expansion chamber to the atmosphere are provided and the damping member is provided to be pinched with an exposed thread at a surrounding of the expansion chamber.
    Type: Application
    Filed: July 8, 2005
    Publication date: January 26, 2006
    Inventors: Yoshinori Ishizawa, Hiroki Kitagawa, Masashi Nishida
  • Publication number: 20060016845
    Abstract: A cylinder is constituted such that the cylinder includes a large diameter portion constituted by forming a portion thereof brought into contact with an O ring by a diameter larger than a diameter of other portion when a piston is disposed at an upper dead center and a small diameter portion formed downward from the large diameter portion, and a fastening margin is provided between an outer periphery of the O ring and an inner periphery of the cylinder even when the piston is disposed at any position from the upper dead center to a lower dead center and a clearance is provided between an inner periphery of the O ring and an outer periphery of a groove.
    Type: Application
    Filed: July 8, 2005
    Publication date: January 26, 2006
    Inventors: Yoshinori Ishizawa, Hiroki Kitagawa, Masashi Nishida
  • Publication number: 20060011695
    Abstract: A magazine cover is integrally molded with a return-preventing claw part to be engaged with a fastener loaded into a guide part. The return-preventing claw part is so constructed as to include: a return preventing surface that abuts against the fastener to prevent the fastener from moving to a loading port; and a support portion that always makes the return preventing surface abut against the fastener, thereby being deformed, to support the return preventing surface such that the return preventing surface can be retracted to a position where the return preventing surface does not abut against the fastener.
    Type: Application
    Filed: July 12, 2005
    Publication date: January 19, 2006
    Inventors: Yoshinori Ishizawa, Hiroki Kitagawa, Masashi Nishida
  • Publication number: 20060011692
    Abstract: A fastener driving tool includes: a driver blade which is driven by compressed air so as to move in a vertical direction for striking a fastener such as a nail, an injection hole which guides said driver blade and forms a passage for the compressed air to be exhausted along with the movement of the driver blade, and a magazine for supplying the fastener to said injection hole, wherein an exhaust passage through which an interior of the injection hole is communicated with the atmosphere is provided between a lower end of the driver blade when the driver blade is positioned at a top dead center and a head part of the fastener which has been supplied into the injection hole.
    Type: Application
    Filed: July 13, 2005
    Publication date: January 19, 2006
    Inventors: Yoshinori Ishizawa, Hiroki Kitagawa, Masashi Nishida
  • Publication number: 20060011694
    Abstract: A fastener driving tool includes: a driver blade adapted to drive nails joined to one another into an object in order; a nose adapted to guide the driver blade and nails; and a guide surface of a projection adapted to guide a head portion of a first nail struck out into an exit hole of the nose so that the second nail is not exposed to the exit hole. The guide surface of the projection is formed to a shape identical with that of the head portions of the nails.
    Type: Application
    Filed: July 14, 2005
    Publication date: January 19, 2006
    Inventors: Yoshinori Ishizawa, Hiroki Kitagawa, Masashi Nishida
  • Publication number: 20050263558
    Abstract: A nail gun is capable of making wear resistance and light-weighted formation compatible with each other by enabling to make a wall thickness of a body or the like as thin as possible by providing a plurality of projected portions having heights in correspondence with wear limits of respective portions at respective portions of a body a head guard for guarding an exhaust cover and the like and reducing wear other than the projected portions.
    Type: Application
    Filed: May 27, 2005
    Publication date: December 1, 2005
    Applicant: Hitachi Koki Co., Ltd.
    Inventors: Yoshinori Ishizawa, Hiroki Kitagawa, Masashi Nishida, Masato Sakai, Takeshi Taniguchi
  • Publication number: 20050211745
    Abstract: A fastener driving tool having a magazine device including a magazine and a nail feeder. The magazine extends in a first direction and defines an accommodation portion for accommodating therein a fastener array. Each fastener has a shaft with a sharp-end and a head connected to the shaft. The plurality of fasteners are directed in a second direction perpendicular to the first direction and positioned side by side to form the fastener array extending in the first direction. The magazine has one end and another end in the second direction. One end is close to the sharp end of the fastener and another end is close to the head of the fastener. The accommodation portion includes an expanding portion having a width in a third direction perpendicular to the first direction and to the second direction. The width is gradually increased from the one end toward the other end.
    Type: Application
    Filed: March 14, 2005
    Publication date: September 29, 2005
    Inventors: Yoshinori Ishizawa, Hiroki Kitagawa, Masashi Nishida
  • Publication number: 20050156008
    Abstract: A pneumatically operated fastener driving tool capable of reducing a time period from operation timing of a trigger to downward movement of a driver blade for fastener driving, and reducing a time period from the release timing of the trigger to a timing at which respective components are returned to their initial positions for a subsequent nail driving. As components a main valve and a trigger valve is provided. The main valve is movable within a main valve chamber connected to a main valve control channel. The trigger valve selectively provides fluid communication between the accumulator and a main valve chamber through the main valve control channel and between the main valve chamber and the atmosphere through the main valve control channel. A ratio of cross-sectional area of the main valve control channel to an internal volume of the main valve chamber is defined to a specified ratio.
    Type: Application
    Filed: January 21, 2005
    Publication date: July 21, 2005
    Inventors: Yoshiichi Komazaki, Yoshinori Ishizawa, Masashi Nishida
  • Publication number: 20050001069
    Abstract: A pneumatically powered nail gun having a duster mechanism which is also pneumatically powered with the same pneumatic source. The nail gun includes a main body having a lower end and defines therein a compressed air chamber. A cylinder piston arrangement is disposed in the main body, and the compressed air is selectively applied to the piston for moving a driver blade connected to the piston to drive a nail. The duster mechanism includes a duster nozzle provided at the main body for ejecting a compressed air therethrough. A pressure release valve is disposed at an air passage extending between the duster nozzle and the compressed air chamber for selectively shutting off a fluid communication therebetween. A pressure regulating section is disposed at the air passage for providing a compressed air passing through the duster nozzle at a pressure lower than that in the compressed air chamber.
    Type: Application
    Filed: August 2, 2004
    Publication date: January 6, 2005
    Inventors: Yoshinori Ishizawa, Yoshihiro Nakano
  • Publication number: 20040238590
    Abstract: An on-off valve has a cylindrical bush through which a fluid is passed, a hole communicating an interior of the cylindrical bush with an atmosphere, an on/off operator which slides along an outer periphery of the cylindrical bush in an axial direction to open and close the hole and a stopper elastic body which is served to position the on/off operator.
    Type: Application
    Filed: May 21, 2004
    Publication date: December 2, 2004
    Applicant: Hitachi Koki Co., Ltd.
    Inventors: Yoshinori Ishizawa, Masao Hamada, Akira Oono
  • Publication number: 20040188488
    Abstract: A plunger is shiftable in response to a trigger operation by a user. A valve piston has a valve piston chamber therein for slidably accommodating the plunger and an axial bore into which the plunger is inserted. An air passage connects the valve piston chamber to an atmosphere via a clearance between the plunger and the axial bore of the valve piston. A seal member is provided to seal the clearance between the plunger and the axial bore of the valve piston. And, a relief passage is formed on at least one of the plunger and the axial bore of the valve piston to open the air passage, thereby allowing compressed air to exit from the valve piston chamber to the atmosphere under a condition where the plunger is engaged with the axial bore of the valve piston.
    Type: Application
    Filed: April 15, 2004
    Publication date: September 30, 2004
    Applicant: Hitachi Koki Co., Ltd.
    Inventors: Yoshinori Ishizawa, Masanori Aoki, Hiroki Kitagawa
  • Patent number: 6783050
    Abstract: A pneumatically powered nail gun having a duster mechanism which is also pneumatically powered with the same pneumatic source. The nail gun includes a main body having a lower end and defines therein a compressed air chamber. A cylinder piston arrangement is disposed in the main body, and the compressed air is selectively applied to the piston for moving a driver blade connected to the piston to drive a nail. The duster mechanism includes a duster nozzle provided at the main body for ejecting a compressed air therethrough. A pressure release valve is disposed at an air passage extending between the duster nozzle and the compressed air chamber for selectively shutting off a fluid communication therebetween. A pressure regulating section is disposed at the air passage for providing a compressed air passing through the duster nozzle at a pressure lower than that in the compressed air chamber.
    Type: Grant
    Filed: May 29, 2003
    Date of Patent: August 31, 2004
    Assignee: Hitachi Koki Co., Ltd.
    Inventors: Yoshinori Ishizawa, Yoshihiro Nakano
  • Patent number: D519809
    Type: Grant
    Filed: October 15, 2004
    Date of Patent: May 2, 2006
    Assignee: Hitachi Koki Co., Ltd.
    Inventors: Takeshi Taniguchi, Masato Sakai, Yoshinori Ishizawa, Hiroki Kitagawa, Masashi Nishida