ANTI-BUMPING CYLINDER

摘要

Provided is an anti-bumping cylinder having a mechanism, which is so disposed at a contact portion of an outer cylinder side to contact an inner cylinder as is fitted on the inner cylinder, so that the fitted portion is fitted, when a pushing stress at a predetermined level or higher is applied by a bumping deed, to suppress the rotation of the inner cylinder. Alternatively in a cylinder system having that fitted portion already fitted in a steady state of no key insertion, the cylinder inner cylinder may burst out forward by the clearance between a tail disc fixed at the back of the inner cylinder and the leading back end portion of the outer cylinder, so that the fitted portion is released to set the rotation of the inner cylinder free. In this case, the fitted portion can be actuated by the pushing stress of a bump key according to the bumping deed, to lock the rotation of the inner cylinder thereby to prevent the bumping deed.