Hair-cutting unit for use in a hair-cutting appliance

A hair-cutting unit for use in a hair-cutting appliance, comprising:

• an external cutting member having a cutting track surface that defines hair-entry openings;
• an internal cutting member having at least one hair-cutting element and being movable with respect to the external cutting member;
• a skin-supporting structure having a skin-supporting surface for contacting a portion of skin to be subjected to a hair-cutting action, wherein the external cutting member is displaceable relative to the skin-supporting structure;
• and
• a safety mechanism designed to enable stepped variation between at least two discrete stages of a level (lc) of the cutting track surface with respect to a level (ls) of the skin-supporting surface, in relation to pressure exerted by the external cutting member on the skin,
• wherein the safety mechanism is configured
• to maintain a default stage as long as the pressure exerted by the external cutting member on the skin is below a predefined threshold value, the default stage involving a most protruding position of the external cutting member in which the cutting track surface protrudes with respect to the skin-supporting surface to a maximum extent, and
• to instantaneously set a retracted stage when the pressure exerted by the external cutting member on the skin increases and passes the predefined threshold value, the retracted stage involving a less protruding position of the external cutting member and a retracted position of the cutting track surface with respect to a position of the cutting track surface in the default stage.