Patents by Inventor Kenji Koiwa

Kenji Koiwa 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: 6497172
    Abstract: A rotary actuator has a cushion mechanism for stopping a vane at a rotational terminal end position in a cushioning manner. The cushion mechanism has first and second openings. The first opening discharges an exhaust air pressed out from a cylinder hole by a rotating vane to an external portion without limiting a flow amount. The second opening discharges the exhaust air to the external portion in a state of limiting a flow amount. A flow amount adjusting mechanism connects to the second opening. The first opening is provided at a position sealed by the vane before the vane of a hole surface in the cylinder hole reaches a rotational terminal end position. The second opening is provided at a position which is not sealed by the vane after the vane reaches the rotational terminal end position.
    Type: Grant
    Filed: March 2, 2001
    Date of Patent: December 24, 2002
    Assignee: SMC Corporation
    Inventors: Akihiro Hirano, Kenji Koiwa, Kiyoshi Takeuchi
  • Patent number: 6435072
    Abstract: The invention provides a rotary actuator having a rack driven in an oscillating manner by an air pressure, a pinion engaged with the rack, and a cushion mechanism for stopping the rack to at least one normal or inverse stroke end in a cushioning manner. The cushion mechanism has an exhaust port open to a pressure chamber at a position close to a chamber end rather than a port hole, a flow amount adjusting mechanism for restricting a flow amount of the exhaust air discharged from the exhaust port, and a cushion packing mounted to an outer peripheral surface of the piston and operating so as to shut the port hole from the pressure chamber immediately before the piston reaches the stroke end, thereby discharging the air within the pressure chamber through the flow amount adjusting mechanism.
    Type: Grant
    Filed: February 27, 2001
    Date of Patent: August 20, 2002
    Assignee: SMC Corporation
    Inventors: Akihiro Hirano, Kenji Koiwa, Kiyoshi Takeuchi
  • Patent number: 6431048
    Abstract: An output shaft is connected to a piston rod of a fluid pressure-driven linear cylinder through a converting mechanism for converting linear thrust of the piston rod into rotational torque and converting operation of the converting mechanism is controlled by operation setting means having a cam groove and a cam follower to thereby causing the output shaft to carry out linear motion and swinging rotation. A driving speed of the piston can be changed by adjusting fluid pressure acting on the piston in a linear motion area and a swinging area of the output shaft respectively.
    Type: Grant
    Filed: February 20, 2001
    Date of Patent: August 13, 2002
    Assignee: SMC Corporation
    Inventors: Kenji Koiwa, Kaichiro Mitsui
  • Publication number: 20010020413
    Abstract: The invention provides a rotary actuator having a rack driven in an oscillating manner by an air pressure, a pinion engaged with the rack, and a cushion mechanism for stopping the rack to at least one normal or inverse stroke end in a cushioning manner. The cushion mechanism has an exhaust port open to a pressure chamber at a position close to a chamber end rather than a port hole, a flow amount adjusting mechanism for restricting a flow amount of the exhaust air discharged from the exhaust port, and a cushion packing mounted to an outer peripheral surface of the piston and operating so as to shut the port hole from the pressure chamber immediately before the piston reaches the stroke end, thereby discharging the air within the pressure chamber through the flow amount adjusting mechanism.
    Type: Application
    Filed: February 27, 2001
    Publication date: September 13, 2001
    Applicant: SMC Corporation
    Inventors: Akihiro Hirano, Kenji Koiwa, Kiyoshi Takeuchi
  • Publication number: 20010018859
    Abstract: An output shaft is connected to a piston rod of a fluid pressure-driven linear cylinder through a converting mechanism for converting linear thrust of the piston rod into rotational torque and converting operation of the converting mechanism is controlled by operation setting means having a cam groove and a cam follower to thereby causing the output shaft to carry out linear motion and swinging rotation. A driving speed of the piston can be changed by adjusting fluid pressure acting on the piston in a linear motion area and a swinging area of the output shaft respectively.
    Type: Application
    Filed: February 20, 2001
    Publication date: September 6, 2001
    Applicant: SMC Corporation
    Inventors: Kenji Koiwa, Kaichiro Mitsui
  • Publication number: 20010018864
    Abstract: The invention provides a rotary actuator having a cushion mechanism for stopping a vane at a rotational terminal end position in a cushioning manner. The cushion mechanism has a first opening for discharging an exhaust air pressed out from a cylinder hole by a rotating vane to an external portion without limiting a flow amount, a second opening for discharging the exhaust air to the external portion in a state of limiting a flow amount and a flow amount adjusting mechanism for limiting a flow amount, the flow amount adjusting mechanism being connected to the second opening, wherein the first opening is provided at a position sealed by the vane before the vane of a hole surface in the cylinder hole reaches a rotational terminal end position, and the second opening is provided at a position which is not sealed by the vane after the vane reaches the rotational terminal end position.
    Type: Application
    Filed: March 2, 2001
    Publication date: September 6, 2001
    Applicant: SMC Corporation
    Inventors: Akihiro Hirano, Kenji Koiwa, Kiyoshi Tekeuchi
  • Patent number: 3935925
    Abstract: A horn speaker having wide directional characteristics in accordance with the present invention provides a horn having a horn wall the shape of which is formed by connecting a plurality of curves having different flaring constants. The flaring constant of the curve forming a mouth portion of the horn wall is selected so as to be greater than that of the curve forming a throat portion thereof. The mouth portion of the horn wall is shaped so as to have a flaring angle which is formed by the curve at the mouth portion and has no abrupt variation of angle to a baffle plate. The curve at the mouth portion is connected with the curve at the horn wall nearer to the throat portion and having the flaring constant different therefrom at a point at which the differential coefficients of the respective curves substantially coincide with each other.
    Type: Grant
    Filed: November 2, 1973
    Date of Patent: February 3, 1976
    Inventors: Kenji Koiwa, Makoto Kohashi