A double-reeved lifting device for a lifting machinery, such as a crane, comprising two reeve blocks (3, 4), namely a lower reeve block secured to a lifting hook and an upper reeve block, wherein the two reeve blocks (3, 4) comprise a mechanical reversible connection system to be reversibly configurable between: - a connected configuration wherein the upper reeve block is connected to the lower reeve block to be able to accompany it in ascending/descending movements along a main axis, and - a disconnected configuration wherein the upper reeve block is disconnected from the lower reeve block to be able to remain hanging above the lower reeve block which can perform ascending/descending movements without the upper reeve block, wherein the mechanical reversible connection system comprises a locking mechanism mounted on one of the two reeve blocks (3, 4), and a complementary locking structure mounted on the other of the two reeve blocks (3, 4) and comprising a locking member capable of cooperating with the locking mechanism; and wherein the locking mechanism comprises: - a chassis having a locking channel of elongated shape along the main axis and provided with a mouthpiece through which the locking member can enter and exit the locking channel and can slide in the locking channel in an entry direction and in an exit direction, opposite to the entry direction, respectively upon a relative approach or a relative distancing between the two reeve blocks (3, 4), and - at least one pawl pivotally mounted on the chassis around a pivot axis so as to pivot inside the locking channel, said pawl being provided with a free end adapted to engage with the locking member, said locking mechanism being characterized in that it further comprises: - a thrust stop provided with a free front end adapted to abut against the pawl, said thrust stop being movably mounted on the chassis between a maximum advanced position in the absence of a thrust exerted by the pawl on said free front end, and retracted positions in the presence of a thrust force exerted by the pawl on said free front end; and - an elastic return member urging said thrust stop towards its maximum advanced position and providing a force resisting the thrust force exerted by the pawl on said free front end. - a connected configuration wherein the upper reeve block is connected to the lower reeve block to be able to accompany it in ascending/descending movements along a main axis, and - a disconnected configuration wherein the upper reeve block is disconnected from the lower reeve block to be able to remain hanging above the lower reeve block which can perform ascending/descending movements without the upper reeve block, wherein the mechanical reversible connection system comprises a locking mechanism mounted on one of the two reeve blocks (3, 4), and a complementary locking structure mounted on the other of the two reeve blocks (3, 4) and comprising a locking member capable of cooperating with the locking mechanism; and wherein the locking mechanism comprises: - a chassis having a locking channel of elongated shape along the main axis and provided with a mouthpiece through which the locking member can enter and exit the locking channel and can slide in the locking channel in an entry direction and in an exit direction, opposite to the entry direction, respectively upon a relative approach or a relative distancing between the two reeve blocks (3, 4), and - at least one pawl pivotally mounted on the chassis around a pivot axis so as to pivot inside the locking channel, said pawl being provided with a free end adapted to engage with the locking member, - a chassis having a locking channel of elongated shape along the main axis and provided with a mouthpiece through which the locking member can enter and exit the locking channel and can slide in the locking channel in an entry direction and in an exit direction, opposite to the entry direction, respectively upon a relative approach or a relative distancing between the two reeve blocks (3, 4), and - at least one pawl pivotally mounted on the chassis around a pivot axis so as to pivot inside the locking channel, said pawl being provided with a free end adapted to engage with the locking member, said locking mechanism being characterized in that it further comprises: - a thrust stop provided with a free front end adapted to abut against the pawl, said thrust stop being movably mounted on the chassis between a maximum advanced position in the absence of a thrust exerted by the pawl on said free front end, and retracted positions in the presence of a thrust force exerted by the pawl on said free front end; and - an elastic return member urging said thrust stop towards its maximum advanced position and providing a force resisting the thrust force exerted by the pawl on said free front end. - a thrust stop provided with a free front end adapted to abut against the pawl, said thrust stop being movably mounted on the chassis between a maximum advanced position in the absence of a thrust exerted by the pawl on said free front end, and retracted positions in the presence of a thrust force exerted by the pawl on said free front end; and - an elastic return member urging said thrust stop towards its maximum advanced position and providing a force resisting the thrust force exerted by the pawl on said free front end.