An implantable motor device comprising a mechanical energy source arranged rotationally mobile about a shaft which defines an axis of rotation and is kinematically linked with, on the one hand, a device for charging the mechanical energy source, and, on the other hand, a member for coupling to an energy-consuming device, the device for charging the mechanical energy source comprising: - a first member and a second member for attachment respectively to a first element or member and a second element or member which are mobile in relation to one another in a patient's body and arranged such that relative displacement of the first and second elements or members brings about an analogous relative displacement of said first and second attachment members; - means (6, 7, 8) for winding the mechanical energy source, said winding means being connected to said first and second attachment members and comprising: i. a ratchet integral with the shaft of rotation, said ratchet comprising triangular peripheral teeth, and ii. a flywheel for unidirectionally driving the ratchet in rotation with the shaft, said flywheel bearing pawls mobile in rotation on a rim of the flywheel said pawls comprising teeth complementary to those of the ratchet so as to mesh with the peripheral teeth of the ratchet in just one direction of rotation on each relative displacement of said first and second attachment members, characterised in that the motor device furthermore comprises means (9, 10, 11, 12, 102, 16) for sequentially liberating said means (6, 7, 8) for winding the mechanical energy source to liberate said energy source in rotation in order to transmit an available driving torque to the coupling member, said means for sequentially liberating said winding means of the mechanical energy source comprising: - a cam integral with the mechanical energy source and - a release pawl mounted rotationally mobile about an axis parallel to the axis of rotation, one end of said pawl being held in abutment by a return member in a notch formed in a surface of said cam, and - a release finger integral with said release pawl and arranged to cooperate with a pin integral with the ratchet in a single position of said ratchet so as to pivot said release pawl in such a manner that its end exits from the notch of the cam and liberates the mechanical energy source in rotation to transmit a drive torque to the coupling member, - a locking lever rotationally integral with the release pawl and arranged to cooperate in abutment with a locking finger when the end of the release pawl is inserted in the notch. - a first member and a second member for attachment respectively to a first element or member and a second element or member which are mobile in relation to one another in a patient's body and arranged such that relative displacement of the first and second elements or members brings about an analogous relative displacement of said first and second attachment members; - means (6, 7, 8) for winding the mechanical energy source, said winding means being connected to said first and second attachment members and comprising: i. a ratchet integral with the shaft of rotation, said ratchet comprising triangular peripheral teeth, and ii. a flywheel for unidirectionally driving the ratchet in rotation with the shaft, said flywheel bearing pawls mobile in rotation on a rim of the flywheel said pawls comprising teeth complementary to those of the ratchet so as to mesh with the peripheral teeth of the ratchet in just one direction of rotation on each relative displacement of said first and second attachment members, characterised in that the motor device furthermore comprises means (9, 10, 11, 12, 102, 16) for sequentially liberating said means (6, 7, 8) for winding the mechanical energy source to liberate said energy source in rotation in order to transmit an available driving torque to the coupling member, said means for sequentially liberating said winding means of the mechanical energy source comprising: i. a ratchet integral with the shaft of rotation, said ratchet comprising triangular peripheral teeth, and ii. a flywheel for unidirectionally driving the ratchet in rotation with the shaft, said flywheel bearing pawls mobile in rotation on a rim of the flywheel said pawls comprising teeth complementary to those of the ratchet so as to mesh with the peripheral teeth of the ratchet in just one direction of rotation on each relative displacement of said first and second attachment members, - a cam integral with the mechanical energy source and - a release pawl mounted rotationally mobile about an axis parallel to the axis of rotation, one end of said pawl being held in abutment by a return member in a notch formed in a surface of said cam, and - a release finger integral with said release pawl and arranged to cooperate with a pin integral with the ratchet in a single position of said ratchet so as to pivot said release pawl in such a manner that its end exits from the notch of the cam and liberates the mechanical energy source in rotation to transmit a drive torque to the coupling member, - a locking lever rotationally integral with the release pawl and arranged to cooperate in abutment with a locking finger when the end of the release pawl is inserted in the notch.