A mounting assembly for a hair cutting appliance, the mounting assembly comprising: a head comprising a body, extending along an elongate axis, and a driving bridge, the head 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 along the elongate axis; a base connected to the head with a first pivoting mechanism; a driving unit comprising a driving axle and a socket, the driving axle comprising an eccentric pin cooperating with the driving bridge to impart reciprocating motion to the driving bridge, and the socket being configured to cooperate with a motor; wherein the first pivoting mechanism comprises: a base bearing surface on the base, a counterpart coupled to the head, the counterpart comprising a counterpart bearing surface, wherein the base bearing surface and the counterpart bearing surface are configured to cooperate to permit relative rotational sliding movement of the base and the head about only a fixed rotational axis which is perpendicular to the elongate axis wherein one of the base bearing surface or the counterpart bearing surface comprises an inner surface of a slot having a curvature about the fixed rotational axis, and wherein the other of the base bearing surface or the counterpart bearing surface comprises an outer surface of a pin which is configured to be received within the slot. a head comprising a body, extending along an elongate axis, and a driving bridge, the head 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 along the elongate axis; a base connected to the head with a first pivoting mechanism; a driving unit comprising a driving axle and a socket, the driving axle comprising an eccentric pin cooperating with the driving bridge to impart reciprocating motion to the driving bridge, and the socket being configured to cooperate with a motor; wherein the first pivoting mechanism comprises: a base bearing surface on the base, a counterpart coupled to the head, the counterpart comprising a counterpart bearing surface, wherein the base bearing surface and the counterpart bearing surface are configured to cooperate to permit relative rotational sliding movement of the base and the head about only a fixed rotational axis which is perpendicular to the elongate axis wherein one of the base bearing surface or the counterpart bearing surface comprises an inner surface of a slot having a curvature about the fixed rotational axis, and wherein the other of the base bearing surface or the counterpart bearing surface comprises an outer surface of a pin which is configured to be received within the slot. a base bearing surface on the base, a counterpart coupled to the head, the counterpart comprising a counterpart bearing surface, wherein the base bearing surface and the counterpart bearing surface are configured to cooperate to permit relative rotational sliding movement of the base and the head about only a fixed rotational axis which is perpendicular to the elongate axis wherein one of the base bearing surface or the counterpart bearing surface comprises an inner surface of a slot having a curvature about the fixed rotational axis, and wherein the other of the base bearing surface or the counterpart bearing surface comprises an outer surface of a pin which is configured to be received within the slot.