| 摘要 |
The ends of the legs of a V-shaped projection has catches which point outwards and engage the inside surface of the drum when the former is pushed through a U-shaped slot in the drum surface. The matl. which formed the slot is bowed and pressed against the inside surface of each leg. The rib, which fills the area between the legs except at the point where the drum matl. is bowed, presses against the drum surface in the middle of the U-shaped slot and provides reaction force to keep the latches in place. Complicated top tools are not needed for insertion of the projections. |
