| 摘要 |
<p>In the case of each of the demountable pencils (23), the end part of the protecting tube (27) which is open outwards is reduced in diameter over a certain length and comprises at least one housing passing or not passing through its wall. The end part of the pencil (23) is integrally attached to a shell (34) which is coaxial relative to the pencil and surrounds the rod (31) for assembling this pencil over a part of its length. The shell (34) is engaged over the reduced-diameter part of the protecting tube (27) when the rod (31) is screwed into the bore (28) of the protecting tube. Locking of the pencil in rotation in the protecting tube (27) is produced by distortion of the shell (34) inside the openings of the end part of the protecting tube (27). Disassembly of the pencil is performed by applying a torque to this pencil by means of a gripping surface, for example of prismatic shape, (37) situated in the vicinity of the end of the pencil.
<IMAGE></p> |
