Abstract: A pressure dehydration low-frequency washing machine with a simplified structure using a single motor and a driving mechanism, including an electromotive rotation shaft horizontally installed below a washing tub, a selective drive for driving an oscillating plate of the washing tub by selectively converting rotation force of the electromotive rotation shaft to a reciprocation force according to the rotation direction of the electromotive rotation shaft, an air-compressor for converting the rotation force of the electromotive rotation shaft to a reciprocation force and compressing air by means of a piston driven by the reciprocation force, a pressure-applying dehydrator for applying pressure and dehydrating the laundry in the washing tub by being expanded by compressed air from the air-compressor when the electromotive rotation shaft is rotated in a direction where the selective drive is not driven, and a controller for selectively transferring the compressed air in the air-compressor to the pressure-applying

Abstract: A bulged washing tub for a low frequency vibration type washing machine is disclosed. The side wall of the washing tub is outwardly bulged so that this side wall meets with the bottom of the washing tub at an obtuse angle and smoothly guides the heart type or scroll type water current in the washing tub. A plurality of friction prominences of the horizontal stripe type are provided on the inner surface of the outward bulged side wall. The prominences give frictional force to clothes when the clothes are rubbed against them while coming up and going down along with the water current in the washing tub. The frictional force caused by the prominences causes a so-called washboard effect and makes the clothes cleaned as if they were manually washed using a washboard.

Abstract: A low frequency vibration type washing machine has an oscillating disc suitable for both generation of an effective circulation current in the multi-phase washing medium and prevention of energy loss. The oscillating disc vertically vibrates in the multi-phase washing medium in the washing tub at different ascending and descending velocities, thus to generate an effective circulation current in the multi-phase washing medium. A plurality of perforations are formed in the oscillating disc for both reduction of the washing medium resistance and generation of the effective circulation current in the washing medium. The washing machine also has an elastic body mounted on the oscillating disc for preservation of vibration energy loss of the washing medium in the form of elastic energy. The washing tub is preferably rounded at its inner bottom corner and at its inner bottom center about the disc drive shaft penetrating the bottom center.

Abstract: A low frequency vibration type washing machine having at least one horizontally reciprocating disk is disclosed. The disk is provided on the side wall of the washing tub and horizontally vibrates in a direction perpendicular to the direction of gravity of the multi-phase washing medium, thus to generate the resonance phenomena in the washing medium inside the washing tub while saving disk drive energy. The multi-phase washing medium is made of water, detergent and air. The washing machine also includes an actuator which is coupled to the disk for driving this disk. In an embodiment, two disks are provided on the side wall of the washing tub in such a manner that they face each other. In this case, the disks may vibrate so as to form vibrational waves of the same phase or of different phases. The vibrational waves of the disks may have a phase difference larger than -.pi./2 and less than .pi./2.

Abstract: A low frequency vibration type washing machine has a shrinkable shielder for prevention of clothes jamming in the gap between the low frequency vibrating disc and the inner bottom of the washing tub from the outside. The washing machine includes the washing tub and a vibrating disc placed in the washing tub for causing resonance phenomena in a multi-phase washing medium received in the washing tub. The shrinkable shielder is placed in the gap such that it shields the gap from the outside. The shielder totally or partially shields the gap and is made of rubber or sponge. The shielder may be a tube type shielder placed in the gap at a lower edge of the vibrating disc. Alternatively, the shielder may be a spring type shielder. As a further alternative, the shielder may be a flexible thin film annularly placed in the gap at a lower edge of the vibrating disc. The tube type shielder is charged with gas or liquid.

Abstract: A low frequency vibration type washing machine is disclosed that is capable of detecting the range of linear reciprocating movement of its drive shaft to control the vibration range of its low frequency oscillating vibrator to be constant, and sensing water level in its washing tub to control the water level. The washing machine includes a low frequency oscillating vibrator adapted to vibrate in a washing tub while being subjected to a water level pressure. The vibrator thereby generates a resonance phenomenon in a multi-phase medium contained in the washing tub.

Abstract: An input energy saving device for a low frequency vibration type washing machine. The device lets the resonance frequency of the washing tub and the input frequency of the oscillating disc be equal to each other during generation of resonance phenomena in the multi-phase washing medium for clothes washing, thus to save the input energy required in generation of the resonance phenomena. The device comprises a washing tub receiving multi-phase washing medium therein and an oscillating disc provided in the washing tub for generation of resonance phenomena in the washing medium. A flexible elastic body is placed between the disc and the inner bottom of the washing tub for letting the input frequency of the disc means and the resonance frequency of the washing tub be equal to each other. An actuator is coupled to the disc through a shaft so as to drive the disc means.