Patent ID: 6981812

Claim:
An opening and closing device for a capless retractable marker pen, wherein the opening and closing device is disposed within a pen tube, and the opening and closing device comprises: a supporting device having an upper opening and a lower opening, wherein a plurality of hooks are disposed around the lower opening, and a protrusion is disposed in a substantially central portion of an outer surface of each hook; a cover holder having an upper ring, a plurality of supports connected to the upper ring and a lower ring connected to the supports, wherein the upper ring is coaxially disposed outside the supporting device and clipped between a rear end of each hook and each protrusion; a sealing member coaxially clipped within the lower ring and covering a writing tip disposed in the supporting device and the cover holder, wherein the sealing member includes a cover plate and a cover supporting tube, and a side of the cover plate is movably disposed on a side of the lower ring; and a spring member coaxially disposed within the supporting device, wherein the spring member shores the supporting device and the cover supporting tube by elastic force, so as to make the cover plate cover a lower surface of the cover supporting tube to seal the writing tip, wherein when the writing tip moves downward, the opening and closing device descends to an arc protrusion in the pen tube, and the cover holder continuously rises across the protrusions of the supporting device to reach the outside of the upper opening of the supporting device, wherein with the rise of the cover holder, the cover plate is opened to make the writing tip project from the cover supporting tube.