| 摘要 |
A first extension section extends approximately at right angles from that portion of a cover plate which is in the vicinity of an opening of a cylinder, in such a way as to cover a plane section of the opening. A second extension section extends from a side edge of the first extension section in such a way as to cover an inclined section which tilts obliquely outward from the opening. Furthermore, a base plate is formed in such a way that a pressing section extends by a predetermined length, so as to face the upper side of the second extension section, from that portion of a base plate which is in the vicinity of the inclined section formed by being partially cut obliquely outward from the opening of the cylinder. |
