Abstract: A push or pull type device for operating a lock bolt includes a support attached to a door carrying the lock. This support carries a cam rotatably mounted on a plate and including a square hole for a corresponding cross-section rod to be inserted into the lock to operate the bolt. An actuator member mounted to pivot about a rotation axis substantially parallel to the plate has two spaced lugs whose paths on pivoting lie on either side of the rotation axis of the cam. A handle is an integral part of or is removably mounted on the actuator member and angular play connected with a pre-orientation of the nut is compensated elastically.