Jig for holding an inner plug

摘要

A jig (D or Da) for holding an inner plug (B or B2) unrotatably. The inner plug (B or B2) comprises a lip cylinder (4 or 44), a threaded cylinder (5 or 45) and an engaging portion (3 or 43). The engaging portion (3 or 43) comprises an outer cylinder (6 or 46) and an inner cylinder (7 or 47). In one embodiment, the inner plug (B) is provided with a lot of longitudinal ribs (19) between the lip cylinder (4) and the threaded cylinder (5). The jig (D) comprises a column (82) and a cylinder (83), the column (82) having a diameter substantially the same as a diameter of an inner surface of said inner cylinder (7). The cylinder (83) extends from an outer periphery of the column (82) and has a thickness substantially the same as a space (T) between the lip cylinder (4) and the threaded cylinder (5). The cylinder (83) is provided with slits (84) corresponding to said longitudinal ribs (19). In another embodiment, the lip cylinder (44) has a partition wall (61). The partition wall (61) is provided on a lower surface thereof with an inner wall (62) aligned and below the lip cylinder (44). The inner wall (62) is formed with vertical ribs (63) on an inner surface thereof. The jig (Da) comprises a holding base (92) and a support step (93) for receiving a lower end of the inner wall (62) of the inner plug (B2). The holding base (92) is provided with vertical grooves (94) which engage with the vertical ribs (63). The holding base (92) has an outer surface which engages with an inner surface of the inner wall (62) of the inner plug (B2).