| 摘要 |
PROBLEM TO BE SOLVED: To prevent a rod from advertently coming off from a piston by setting the length of the axial direction of the higher part of the female screw hole of the laminate piston and the lower part of the male part of the rod to be larger. SOLUTION: An injector is formed of a barrel and a plunger and the plunger is formed of the laminate piston 21 freely slidably fitted into the barrel and the rod 25 to be screwed to the shaft part of the piston 21. Concerning the piston 21, the female screw hole 22 is formed at the shaft part of a rubber piston 21a. The rod 25 is provided with the male screw part 26 at its tip part and screwed to the hole 22. In this case, at the time of setting the axial length of a lower part 22a to be (t) and the axial length of a higher part 22b to be T concerning the length of the axial direction of the part 22a and the part 22b of the hole 22, T>t is set. Thus, at the time of applying pulling out force from the barrel to the rod 25, the rod never comes off from the piston 21 inadvertently. |
