Patent ID: 7931416

Claim:
A slide type writing tool having a dryness prevention unit, comprising: a hollow shaft having at a first end thereof a nib hole; a knock part inserted into an insert hole formed in a second end of the shaft; a cartridge inserted into the shaft to be concentric with the nib hole, and integrated with the knock part; a control module made of an elastic material and comprising: an O-ring part coming into close contact with the nib hole; a spherical door having a spherical surface to isolate a nib from an exterior; a tubular holder secured to the cartridge; a first hinge coupling the O-ring part with the spherical door; and a second hinge integrally coupling the spherical door with the holder; and a spring provided in the shaft, and located between the control module and the cartridge to provide elastic restoring force, whereby, when the knock part is pressed, the spherical door, operated in conjunction with the knock part and the cartridge, is rotated at a rotating angle, thus opening the nib hole of the shaft, therefore causing the nib to be projected outside the nib hole through a passage of the spherical door; wherein the spherical surface of the spherical door has a hemispherical shape, and the open passage is formed opposite the spherical surface, so that the retraction and projection of the cartridge are carried out through the passage when the writing tool is operated; and wherein the spherical door comprises on opposite sides thereof spire-shaped coupling parts which protrude integrally from the spherical surface, the holder comprises spire-shaped coupling parts which extend vertically from opposite sides of an upper opening of the holder, each of the coupling parts being coupled to the corresponding coupling part via the second hinge to rotate the spherical door.