Patents by Inventor Chang-Keun Ryu

Chang-Keun Ryu 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).

  • Guide sleeve for a length-adjustable column for chairs
    Patent number: 5865542
    Abstract: A guide sleeve structure for guiding and supporting the cylinder in the spindle guide tube comprising vertical guide webs(110) formed toward the spindle between the radial line of the ribs(130), and the vertical guide grooves toward the spindle in response to the ribs(130) to structurally withhold the expanding and the shrinking of the slide gap caused by the change of temperature.
    Type: Grant
    Filed: November 18, 1997
    Date of Patent: February 2, 1999
    Inventor: Chang Keun Ryu
  • Height adjusting mechanism for swivel chair
    Patent number: 5342012
    Abstract: A height adjusting mechanism for a swivel chair prevents a tightening phenomenon and involuntary adjustment of the position. The mechanism includes a supporting pillar pipe and a cylinder pipe coupled so that they can freely extend and contract relative to each other. A clutch unit is provided for connecting and disconnecting a height adjusting power transmission. The clutch unit includes a nut clutch and a clutch plate coupled or released to one another and a chamber of predetermined width is defined within the nut clutch. In the chamber, a rubber O-ring is provided for holding the nut clutch.
    Type: Grant
    Filed: January 25, 1993
    Date of Patent: August 30, 1994
    Inventor: Chang-Keun Ryu