| 摘要 |
A novel molded archery arrow (100) includes a cylindrical steel shaft (101) with sharpened tip, a plastic ferrule (102) molded over the shaft (101), and cutting blades (103) serving as fletchings. The shaft (101) has a front end with a sharpened tip and a rear end with a stem, the stem having a smaller diameter than the front end of the shaft. The front end of shaft (101) includes indented rings (116) and the stem includes protruding rings (117) that affix shaft (101) to plastic ferrule (102) during the molding process. Since the ferrule (102) of arrow (100) is plastic, arrow (100) slides with little or no friction when launched from metal barrel (206) of a crossbow (200). In the molding process for arrow (100), an open space (115) is created by a tapered pin inserted into an arrow mold opposite the rear end of the stem of shaft (101). The tapered pin engages an indented portion of the stem and holds the shaft (101) in position in the mold while plastic material in liquid form (liquefied at high temperature) is pumped into the mold to form arrow (100). The mold also includes slots for positioning blades (103) so that holes (106) in blades (103) are inside the mold. Hot plastic is pumped into the mold through the tapered pin, coats the front end and stem of shaft (101) to create the ferrule (102) and extends through holes (106) in blades (103) to hold them in place. |
