With reference to
The barrel (10) is hollow and comprises an inner surface, a front end (11), a rear end (12), a through hole (13), a pipe (14), at least one rib (15), an opening, a cap (16) and two optional finger flanges (17). The front end is closed and comprises an inner surface. The through hole (13) is defined through the front end (11). The pipe (14) is formed on the inner surface of the front end (11) and comprises multiple optional notches (141) and a free end. The notches (141) are defined in the free end. The at least one rib (15) is formed on the inner surface near the front end (11) and each one of the at least one rib (15) may be corresponding to each other. The opening is defined on the rear end. The cap (16) extends from the opening and comprises an inner surface, a circumference and at least one protrusion (161). The at least one protrusion (161) is formed around the circumference and on the inner surface. The finger flanges (17) respectively extend from the rear end (12).
With further reference to
The base (30) is cylindrical, is mounted in the inner tube (20), and comprises a center through hole, at least one tab (31), multiple flexible tabs (32), a center, an outer circumference, an axis, an upper portion and an lower portion. The center through hole is defined in the center of the base (30). The at least one tab (31) protrudes on the outer circumference. The flexible tabs (32) extend from the lower portion, selectively abut with the annular flange (21) and may be corresponding to the notches (141).
The spring (40) is mounted around the upper portion of the base (30) and comprises two ends. One end of the spring (40) abuts against the inner surface of the front end (11) of the barrel (10). The other end of the spring (40) abuts against the tab (31) of the base (30).
The needle hub (50) is mounted in the base (30) and comprises an inner needle (51) and an outer needle (52). The inner needle (51) extends through the center through hole of the base (30). The outer needle (52) extends through the through hole (13) of the barrel (10).
With further reference to
Even though numerous characteristics and advantages of the present invention have been set forth in the foregoing description, together with details of the structure and features of the invention, the disclosure is illustrative only. Changes may be made in the details, especially in matters of shape, size, and arrangement of parts within the principles of the invention to the full extent indicated by the broad general meaning of the terms in which the appended claims are expressed.