Abstract: A hair-cutting apparatus is provided which has an external cutting member (1) and an internal cutting member (7) which is drivable relative to the external cutting member. The external cutting member has lamellae (3) between which hair-entry apertures (4) are formed, and the ends of the lamellae form teeth (9) for raising hairs before the hairs are cut. To increase the efficiency of hair catching the teeth are given different lengths. Preferably, there are long teeth (9a, 9b) and short teeth (91, 92) which alternate with one another.

Abstract: The invention relates to an electrical surface treatment device which is provided with an acoustic surface type detector with which a type of a surface to be treated can be detected during operation. According to the invention, the surface type detector delivers an output signal (u.sub.FT) during operation which is characteristic of the type of surface to be treated and which is determined by a value of a physical quantity of air vibrations reflected by the surface to be treated, which value is measured by a vibration detector of the surface type detector. In a special embodiment, the physical quantity is an amplitude, and the surface type detector is a vibration generator for generating air vibrations having a predetermined amplitude. The generated air vibrations preferably have a frequency of at least 15,000 Hz which varies within a predetermined range.

Abstract: A shaving apparatus is provided which comprises a housing having a shaving head carrying an external shaving member with hair-entry apertures and an internal shaving member which is coupled to a motor in the housing and which is drivable relative to the external shaving member with a combined movement, the combined movement comprising an oscillatory rotation about an axis of rotation of the internal shaving member and a reciprocating movement in the direction of the axis of rotation. The internal shaving member is provided with a support which is flexible in the direction of the axis of rotation but which is stiff in directions transverse to said direction of the axis of rotation, and the support rotatably supports an internal shaving-member holder which is coupled to the motor.

Abstract: The invention relates to a cutting unit for cutting hair, for example, as used in a shaver, comprising a first and a second cutting member, each having teeth and at least one cutting member that can be driven so as to perform a reciprocating movement with respect to the other cutting member, the second cutting member being present between the first cutting member and a locking member. The first cutting member and the locking member are connected together by means of spacers.

Abstract: A cutter foil comprising a metal plate having apertures separated by partitions, each aperture being defined by a surrounding wall projecting inwardly of the plate, the thickness of the partitions being less than the thickness of the surrounding walls.

Abstract: A hair-cutting apparatus has a drivable cutter and a stationary cutter, each of which has teeth extending transversely to the direction of driving, the cutting edges of two co-operating teeth enclosing a cutting angle. Mechanism is provided for variably adjusting the position of the two cutters relative to each other in a direction substantially transverse to the direction of driving, the shape of the cutting edges of the respective teeth being such that the mangitude of the cutting angle is variable depending on the adjusted position.