Abstract: A snap-fit device is provided for joining two parts of any shape together by fitting, perpendicularly to their junction surfaces, at least one element projecting from the junction surface of one of the parts, after slight deformation thereof, into a recess in the junction surface of the other part, and engagement of the projection element, by resilient return thereof, on a surface portion of the recess. Inside the device, a separation actuator is operable for separating the engagement projection from the portion on which it is engaged, against the resilient return force of the projection. The separation means is externally activated by a hydraulic or pneumatic pressure or a vacuum source.