Abstract: An alternating current motor may include a rotor configured to rotate about a longitudinal axis, the rotor comprising a diametrically magnetized permanent magnet. Furthermore, the alternating current motor may include stationary coils having a magnetic axis substantially perpendicular to the rotor's longitudinal axis, the stationary coils adapted to the rotor's outer periphery and being substantially coaxial with the rotor's longitudinal axis. In addition, the alternating current motor may include a stator adapted to the stationary coils' outer periphery and being substantially coaxial with the rotor's longitudinal axis, wherein the diametrically magnetized permanent magnet is configured to cause the rotor's oscillation angle to vary no more than 30% between the rotor's oscillation angle at a beginning value of a frequency range of an alternating current in the stationary coil and the rotor's oscillation angle at an ending value of the frequency range of the alternating current in the stationary coil.

Abstract: A hydraulic apparatus is provided which comprises a liquid-pulse generator, and hydraulic motor connected to said generator by a flexible pipe. The motor is driven by liquid pulses provided by the generator via the pipe. The pulses form standing waves within the pipes with a certain wavelength. In order to insure an efficient energy transfer, the length of the pipe is an odd multiple of the quarter-wavelength.

Abstract: An electrically driven hand-held apparatus for body care, such as a toothbrush, operates by means of a rotating motor. An eccentric pin is driven by the motor and engages in a longitudinal slot defined by a fork which is secured to an instrument holder and in this manner sets the instrument holder supporting the treatment instrument such as the toothbrush in oscillatory motion about its longitudinal axis. In order to permit the oscillation amplitude to be adjusted without alteration of the oscillation frequency, the eccentric pin is fixed on a support inclined to its axis of rotation, the support being set in rotary motion by the motor shaft and the support being set in rotary motion by the motor shaft and the support being axially displaceable on its axis of rotation by means of an external operating knob. The effective eccentricity, that is to say the radial distance of the location of engagement in the longitudinal slot, of the eccentric pin from the axis of rotation of the support is thus variable.

Abstract: A hand-operated appliance for body care by means of an intermittent liquid jet, in particular for massaging the gums and for cleaning the teeth, has a liquid pump which comprises a working chamber connected to an outlet fitted with a spray nozzle, a piston reciprocated therein by an electric motor, an inlet chamber connected to an inlet pipe fed from a liquid reservoir, and an inlet valve located in the connecting aperture between the inlet chamber and working chamber. The inlet valve is biased towards the open position by a spring the force of which is less than the pressure exerted during the working stroke of the piston and tending to close the valve. The liquid reservoir is connected by the inlet chamber of the pump to an ascending pipe acting as an air-vent pipe which is arranged vertically, is open at the top and is branched from the inlet chamber.