English to French Tech/Engineering Patents device for injection of a product into an injection site

said maintaining means comprise a hook (13) fixed with respect to said container,
said hook trapping a rim (27a) located on said plunger rod, the rim being allowed to escape from said hook under the force of the spring only once said container has reached its second position and said spring is in its second state.

le crochet piégeant un rebord ??