Pushchair system convertible into a bicycle seat

A stroller system convertible into a bicycle seat able to be configured in a first deployed configuration allowing its use as a stroller and in a second folded configuration allowing its storage and/or its use as a bicycle seat, the stroller system comprising a rigid foldable chassis able to be fixed to a bicycle luggage rack both in a deployed configuration and a folded configuration, the chassis comprising:

• a seat base structure with a backrest,
• a set of steerable front wheels pivotally mounted about a front transverse axis of the chassis between a deployed position and a folded position,
• a set of rear wheels pivotally mounted about a rear transverse axis of the chassis between a deployed position and a folded position,
• at least one device for locking the front wheel set in its deployed position and in its folded position,
• a removable fixing device on a bicycle luggage rack,
• a pusher mounted on the chassis and whose length is adjustable between a high position in which it forms a handle for the stroller and a low position in which it forms a rear mechanical retainer for the backrest of the bicycle seat, and
• at least one mechanism for locking and unlocking the rear wheel set positioned between the rear axis and the front axis of the chassis, the mechanism being able to cooperate with a stop member secured to the rear wheel set between a locking position in which it maintains the rear wheel set in its deployed position and an unlocking position in which it allows the rear wheel set to pivot towards its folded position, the rear wheel set being maintained in its folded position by the front wheel set when the latter is locked in its folded position.