Anti-trip device for an escape mechanism

An anti-trip device for an escape mechanism, arranged to cooperate with a balance, which pivots about a first pivot axis, whose position is fixed relative to a plate, wherein said device includes a banking pin arranged to be fixed to said plate, and at least one moveable bistable assembly which includes, on the one hand, at least one rotor arranged to be fixed to said balance and to pivot synchronously therewith, and on the other hand, a moveable bistable lever that pivots relative to said rotor about a second pivot axis, parallel to said first pivot axis, over a limited angular sector between two indexing positions that can be occupied by indexing means comprised in said bistable assembly for memorising the position of said balance, wherein at least one part of the trajectory of said bistable lever interferes with said banking pin when said balance pivots, and said bistable assembly further includes amplitude limiting means for limiting the amplitude of angular pivoting of said balance in the event of a shock.