A mechanism for a timepiece, comprising: - a regulator mechanism adapted to oscillate with a periodical movement; - an energy distribution member having teeth ; - a blocking mechanism cooperating with the energy distribution member , said blocking mechanism being controlled by the regulator mechanism to regularly and alternatively hold and release the energy distribution member so that said energy distribution member may move step by step according to a repetitive movement cycle; - a monostable elastic member adapted to bear on the teeth of the energy distribution member , said monostable elastic member normally having a first geometrical configuration, said monostable elastic member being arranged such that during each movement cycle of the energy distribution member : - one tooth of said energy distribution member elastically deforms said monostable elastic member from said first geometrical configuration; - and then said monostable elastic member elastically returns to the first geometrical configuration, thereby releasing mechanical energy to the regulator mechanism , wherein the regulator mechanism has an inertial regulating member (17; 117; 217; 317) which is mounted on a support (12-15, 11a) by a first elastic suspension (21; 121; 221; 321) and the blocking mechanism has a blocking member (8; 108; 208) which is connected to the regulating member (17; 117; 217; 317) by at least an elastic link (27; 127; 227; 327) so as to move in synchronism with said regulating member (17; 117; 217; 317), said blocking member (8; 108; 208) being connected to the monostable elastic member and cooperating with the energy distribution member to alternatively hold and release said energy distribution member, wherein said blocking member (8; 108; 208) is connected to the support by a second elastic suspension (33; 133; 233). - a regulator mechanism adapted to oscillate with a periodical movement; - an energy distribution member having teeth ; - a blocking mechanism cooperating with the energy distribution member , said blocking mechanism being controlled by the regulator mechanism to regularly and alternatively hold and release the energy distribution member so that said energy distribution member may move step by step according to a repetitive movement cycle; - a monostable elastic member adapted to bear on the teeth of the energy distribution member , said monostable elastic member normally having a first geometrical configuration, said monostable elastic member being arranged such that during each movement cycle of the energy distribution member : - one tooth of said energy distribution member elastically deforms said monostable elastic member from said first geometrical configuration; - and then said monostable elastic member elastically returns to the first geometrical configuration, thereby releasing mechanical energy to the regulator mechanism , wherein the regulator mechanism has an inertial regulating member (17; 117; 217; 317) which is mounted on a support (12-15, 11a) by a first elastic suspension (21; 121; 221; 321) and the blocking mechanism has a blocking member (8; 108; 208) which is connected to the regulating member (17; 117; 217; 317) by at least an elastic link (27; 127; 227; 327) so as to move in synchronism with said regulating member (17; 117; 217; 317), said blocking member (8; 108; 208) being connected to the monostable elastic member and cooperating with the energy distribution member to alternatively hold and release said energy distribution member, wherein said blocking member (8; 108; 208) is connected to the support by a second elastic suspension (33; 133; 233). <EOS>