Patent ID: 7971392

Claim:
An opening and closing device comprising a roller unit in rolling contact with a rail disposed in a lower end of a support frame, a pane frame support unit disposed in a lower end of a pane frame said pane frame support unit selectively movable away from and towards the roller unit in a vertical direction, a handle rotatably provided on a leading end of the pane frame, and a lift operating unit, selectively moving the pane frame support unit and said pane frame in the vertical direction away from and towards the roller unit in response to rotation of the handle, wherein the lift operating unit comprises: a lift operating bar provided in the leading end of the pane frame said lift operating bar being movable in the vertical direction relative to said pane frame, the lift operating bar being coupled to the roller unit by a lift connection arm, the lift operating bar including a rack receiving slot having a predetermined length and formed in the lift operating bar at a position adjacent to the handle; and a lift operating gear unit, comprising a drive gear coupled to the handle so that the drive gear is rotated by rotation of the handle, a driven gear coupled to and increasing a rotating force of the drive gear, and a rack gear placed in the rack receiving slot of the lift operating bar so as to be movable in the vertical direction relative to the lift operating bar, the rack gear engaging with the driven gear and converting the rotating force into a linear motion force.