This thesis takes place in a hospital in search of an innovative time system. The design of working time can be considered a social innovation for its positive effects on living conditions. Nevertheless, social innovation is revealed as much in the solutions as in their creation process. The latter is based on the participation of the actors concerned, and on the collaboration of a diversity of actors. In ergonomics, the design of new schedules is inseparable from a collective reflection on the content of work; it is the result of a compromise negotiated with the actors concerned. Thus, we propose an innovative approach to the design of atypical working hours, deployed in a pneumology department. The multifactorial and systemic analysis of the initial work situation allows us to identify the salient problems and to formulate principles, leading to proposed solutions (phase 1). All of this information is shared with the actors to build a shared diagnosis and to proceed with an initial processing of the solutions (phase 2). The projection of the solutions is framed by a participatory and multi-actor mechanism, based on intermediate supports inspired by organizational simulation (phase 3). The selected solutions are tested and evaluated in real-life situations (phase 4). The results show that the design of new schedules is an opportunity to engage the actors in a common reflection on the means to reduce the constraints of the work content. The manipulation and verbalization of the intermediate objects facilitates access to the real work of each other, the crossing of points of view, and the questioning of the power players. The device allows the actors to grasp the interdependence of their activities and the projected solutions. Thus, this thesis proposes an update of the work time design approach, and contributes to enrich the concept of social innovation from the point of view of its process.