Shaving apparatus with electrically adjustable cutting unit

Abstract

A shaving apparatus (1, 105) with at least one adjustable cutting unit (11, 121) which comprises an external cutting member (13, 123) with at least one hair trap opening (17) and an internal cutting member (19, 125) which is rotatable inside the external cutting member (13, 123) by means of an electric motor (23, 127). The cutting unit (11, 121) is adjustable by means of an electrical actuator (91, 179) which is controllable by an electrical control unit (103, 191). In a first embodiment of the shaving apparatus (1), the external cutting member (13, 123) can be positioned relative to a holder (17) during a shaving operation by means of the actuator (91). In a second embodiment of the shaving apparatus (105), the external cutting member (123) is displaceable relative to the holder (111) under the influence of a skin contact force against a pretensioning force which has a value which is adjustable by means of the actuator (179). In both embodiments, the motor (23, 127) has a speed which is controlled by the control unit (103, 191). The control unit (103, 191) adjusts the cutting unit (11, 121) and the motor speed (23, 127) as a function of a measured skin contact force, a measured cutting frequency, a time which has elapsed during a shaving operation, and a balance between shaving performance and shaving comfort desired by the user. In a special embodiment, the control unit (103, 191) controls the cutting unit (11, 121) and the motor speed in accordance with an algorithm based on fuzzy logic. The shaving apparatus (1, 105) provides a user of the shaving apparatus (1, 105) with an optimum balance between the achieved shaving performance, i.e. skin smoothness and shaving speed, and the experienced shaving comfort, i.e. skin irritation level, during a shaving operation.