1 in its closed position according to the invention male articulation component 4 may as chosen be either mounted in a removable manner in its housing 5 of frame 1 to allow cover 2 if desired to be pulled off frame 1 in its upright position or to be connected in its housing 5 so that cover 2 cannot be disassembled from frame 1 thus articulation 3 of the invention with the same cast elements can as chosen be made part of the frame so that cover 2 cannot be disassembled or attached in a removable manner in its housing 5 of frame 1 to allow cover 2 to he pulled off the frame to this end male articulation component 4 includes cylindrical barrel 7 set in housing 5 of frame 1 housing which is configured in the form of a clevis for support of hinge pin 8 which goes freely through longitudinal bore 9 of barrel 7 and is attached in a tamper proof manner to the clevis of housing 5 more precisely the clevis of housing 5 is defined by two essentially parallel walls 10 externally connected to circular peripheral rim 1 a of frame 1 in which cover 2 is set each wall 10 is thus situated in the extension of a chord of frame 1 hinge pin 8 goes through holes 10 a in each of walls 10 which are perpendicular to the hinge pin 8 and ends of the hinge pin 8 are connected to the respective walls 10 for example each end of hinge pin 8 is connected by welding to the external side of wall 10 as indicated at 11 in fig2 and 4 male component 4 of articulation 3 also has projecting piece 12 connected radially to cover 2 and which can.