| 摘要 |
At least one rod is normally locked by toothed rollers cooperating with toothed slanted inner portions of V-shaped locking members controlled by a locking cam. The V-shaped locking members are guided within an inner casing of a polygonal shape that has a lower portion for supporting the rod. The lower portion comprises two slanted inner elements which cooperate with a fluted roller placed underneath the underside of the rod. Under an impact, the fluted roller is locked underneath the rod by moving upwardly along one of the two slanted inner elements.
|
