Assembly of an arm head and of an adapter for a windscreen wiper system, corresponding adapter and corresponding arm head and wiper system obtained

The invention relates to an assembly (22) of a wiper arm head T and an adapter (2) for a vehicle windshield wiper system, said adapter (2) being configured so that a connector of a blade of the wiper system can be mounted in rotatable motion on said adapter (2) by means of at least one flexible tab (2b) of the adapter capable of establishing a pivot connection with said connector, said assembly (22) being configured to immobilize said tab (2b) after installation of the blade in the wiper arm head T.