A mounting assembly for a hair cutting appliance , the mounting assembly comprising: a base and a head , the head comprising a body and a driving bridge and being configured to receive a cutting unit , wherein the driving bridge is configured to couple to the cutting unit and to reciprocally move relative to the body ; a pivoting mechanism disposed between the head and the base and configured to permit pivoting movement of the head relative to the base about a primary axis and a secondary axis ; and a driving unit comprising a frame and a driving axle , wherein the frame is rotatable relative to the driving axle about an elongate axis of the driving axle , and provides a bearing surface for the driving axle ; wherein the frame comprises a body coupling which is configured to couple to the body of the head to permit pivoting movement of the head relative to the frame about a body pivot axis which is parallel to the primary axis , and wherein the driving unit comprises a base coupling which is configured to couple to the base to permit pivoting movement of the frame relative to the base about a base axis which is parallel to the secondary axis ; wherein the driving axle comprises: an eccentric driving pin at a distal end of the driving axle , the eccentric driving pin configured to interact with the driving bridge to induce reciprocating movement to the driving bridge relative to the body of the head ; and a socket on a proximal end of the axle for engaging with a driving head on a motor axle for rotary transmission. a base and a head , the head comprising a body and a driving bridge and being configured to receive a cutting unit , wherein the driving bridge is configured to couple to the cutting unit and to reciprocally move relative to the body ; a pivoting mechanism disposed between the head and the base and configured to permit pivoting movement of the head relative to the base about a primary axis and a secondary axis ; and a driving unit comprising a frame and a driving axle , wherein the frame is rotatable relative to the driving axle about an elongate axis of the driving axle , and provides a bearing surface for the driving axle ; wherein the frame comprises a body coupling which is configured to couple to the body of the head to permit pivoting movement of the head relative to the frame about a body pivot axis which is parallel to the primary axis , and wherein the driving unit comprises a base coupling which is configured to couple to the base to permit pivoting movement of the frame relative to the base about a base axis which is parallel to the secondary axis ; wherein the driving axle comprises: an eccentric driving pin at a distal end of the driving axle , the eccentric driving pin configured to interact with the driving bridge to induce reciprocating movement to the driving bridge relative to the body of the head ; and a socket on a proximal end of the axle for engaging with a driving head on a motor axle for rotary transmission. an eccentric driving pin at a distal end of the driving axle , the eccentric driving pin configured to interact with the driving bridge to induce reciprocating movement to the driving bridge relative to the body of the head ; and a socket on a proximal end of the axle for engaging with a driving head on a motor axle for rotary transmission. <EOS>