Prosthetic hand

1. A prosthetic hand comprising:

a wrist;

a hand palm comprising an inner side and a back side;

a thumb; and

wherein the hand palm comprises at least one construction rotatably supported by the wrist, the construction comprising a finger, bars and joints connecting the bars,

wherein the bars of the finger occupy a position with reference to each other and a deflected position with reference to the wrist depending on, and in a direction of an external load applied to the construction,

wherein a reaction force for the load applied to the construction is provided by or through the wrist,

wherein the construction has an unloaded position wherein the finger is stretched and a plurality of loaded positions corresponding to loads applied to the thumb or to the inner side of the hand palm wherein the construction is deflected from the unloaded position wherein the finger is stretched into the plurality of loaded positions in which the finger is deflected with reference to the wrist and flexed into increasingly bended positions so as to eventually close the prosthetic hand, and

wherein the construction further comprises a locking mechanism to lock the construction in one of the plurality of loaded positions.

2. The prosthetic hand according to claim 1 wherein the locking mechanism comprises a ratchet mechanism comprising a gear with teeth and a pawl to lock the construction in one of the plurality of loaded positions.

3. The prosthetic hand according to claim 2 , wherein the ratchet mechanism comprises two pawls that cooperate with the teeth of the gear wherein the two pawls are arranged to intermittently engage the teeth to lock the construction in one of the plurality of loaded positions.

4. The prosthetic hand according to claim 2 wherein the construction is configured such that unlocking the ratchet mechanism releases the construction to enable it to return to the unloaded position.

5. The prosthetic hand according to claim 2 further comprising an extension disposed on the pawl, and the hand further comprising a switch that is movable into a position wherein it will cooperate with the extension when a load is applied to the construction to remove the pawl from the teeth of the gear.

6. The prosthetic hand according to claim 2 , wherein at least a plurality of the bars are disposed at the inner side of the hand palm and are slidable with reference to each other and wherein distant extremities of the bars comprise a spring configured to bring the bars closer to each other.

7. The prosthetic hand according to claim 2 wherein the thumb is disposed on at least one of the bars of the construction and the construction is disposed at the back side of the hand palm.

8. The prosthetic hand according to claim 2 , wherein the at least one construction comprises four constructions, each of which comprises a finger, wherein at least one of the fingers is independently movable with respect to the other fingers.

9. The prosthetic hand according to claim 8 , wherein at least one of the bars comprises an intermediate swivel bar mounted to at least one of the joints at the end of the bar closest to the wrist.