Abstract: A system for assembling first and second parts of a device, including first and second coupling elements respectively associated with the first and second parts of the device. The coupling elements each include one or several contact zones arranged for spatially guiding the first and second parts during their relative displacement. These contact zones can consist in one or several sloping ramps arranged in circular manner on the internal face of the first or second corresponding part. The first and second coupling elements can be made without undercut and arranged to be subjected to a deformation during gradual clamping so as to provide a substantially normal resistance at the interface zone.