| 摘要 |
The protector has a rigid tube (1) formed of multiple tubular segments (4) connected together to be separable. The tubular sections define an assembly with an internal volume conforming to a chalk stick (2) received in the protector. Each tubular section can be formed from two axial sections (6,7) of different diameters. The external diameter of the rigid tube is constant after attachment of the tubular sections. Each tubular section can have an external locking rib and an internal locking rib. Each tubular sections can have an annular section on one part and an annular groove on the other.
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