PLASTIC-MADE TWO-HOLE-TYPE TWO-HEADED NEEDLE

摘要

PROBLEM TO BE SOLVED: To satisfy all of a liquid flowing property, an operability at the time of piercing a needle and the stability of coring by permitting a needle tip part to be a nearly conical shape, permitting the horizontal cross section shape of a needle body and two holes to be almost an oblong shape with a prescribed value of a ratio of a long diameter to a short diameter and permitting the total cross section opening area occupation rate of the two holes to be more than prescribed % of the horizontal cross section. SOLUTION: This two-hole-type two-headed needle is formed so as to be an oblong shape being near to a complete circle in the horizontal cross section shape of the needle body 1 and the tario of the long diameter D1 with the short one D2 is set to be within the range of <=1.5. Moreover, a conical shape with small needle piercing resistance is adopted as the tip parts of the upper and lower parts of the needle body 1. Then, the two holes 2 and 3 for a ventilation and liquid passage are provided with the same horizontal cross section opening area and its shape is made close to the complete circle with the ratio of the long diameter d1 to the short one d2 being <=1.7. The holes 2 and 3 are arranged so as to permit the long diameter d1 to be in parallel with the short diameter D2 of the needle mainbody 1 at the both sides with a vertical surface containing the short diameter D2 of the needle mainbody 1 as reference and the total horizontal cross section opening area occupying rate of the two holes 2 and 3 is made to be more than 45% in the horizontal cross section area of the needle mainbody 1.