| 摘要 |
The present invention relates to an air pressure liquid chalk including: a main body capable of accommodating a liquid; a tip coupled with a lower end of the main body and absorbing and discharging to the outside the liquid in the main body; a finish cap coupled with an upper end of the main body, formed of an elastic rubber material or in the shape of bellows, and supplying air pressure into the main body, a through-hole being formed at an upper end of the finish cap for air to flow in; a backflow prevention device coupled with an upper side of the main body and having a lower end where a cut portion is formed, the cut portion being closed based on elasticity and opened based on the air pressure supplied from the finish cap; and a spring coupled with an inner side of the finish cap, an upper end of the spring being in contact with the upper end inside the finish cap and a lower end of the spring maintaining elasticity in contact with an upper end of the backflow prevention device. When the through-hole in the finish cap is pressed by a finger and then released, the cut portion is closed because of a pressure difference in the cut portion and the elasticity of the cut portion itself. The degree of opening of the cut portion varies with the degree to which the through-hole is blocked by the finger. According to the present invention, the elastic finish cap is coupled with the upper end of the liquid chalk and the finish cap supplies the air pressure into the main body. Accordingly, the air pressure is supplied into the main body by the finish cap being pressed by a user and the liquid in the main body is pressed downwards, and thus blurred writing can be prevented that is attributable to no or inadequate liquid discharge to the outside. |
