Packing for a product in powder form comprising a fool-proof lock

A packing for a product in powder form comprising:

• a generally cylindrical upper housing closed at its upper end and including at its lower end section orifices provided in its side and a free edge;
• a lower housing co-axial with respect to the upper housing, the upper part of which is generally cylindrical with a radius r, the lower part is generally cylindrical with a radius R greater than the radius of the upper part, and with a generally tapered middle part, the lower housing being open at its two ends;
• a plug positioned internally within the lower housing and fitted with means engageable with the free edge of the lower end section of the upper housing, the upper housing and the plug defining an assembly sliding axially between a closed position and a maximum opened position;
• means provided on the lower housing for temporarily engaging the lower end section of the assembly to the lower housing to permit locking of the assembly to the lower housing;
• a circular check provided substantially circumferentially around the upper housing for checking the axial sliding of the assembly in relation to the lower housing to define the maximum opened position of the assembly;
• means for blocking the packing in the closed position preventing axial sliding of the upper housing in relation to the lower housing while enabling axial swiveling of the assembly in relation to the lower housing, the blocking means including at least one cut-off abutting against the circular check which includes at least one discontinuity such that when the cut-off is not aligned with the discontinuity, axial sliding is prevented.