GB1020758A - Improvements in or relating to washing machines - Google Patents

Abstract

A washing machine drum is driven by a variable-speed motor via an infinitely-variable V-belt unit, the transmission ratio of the latter being changed when a speed intermediate the washing and spin-drying speeds is exceeded. In a first embodiment (Fig. 1, not shown), a 2-4-6-pole-changing motor drives the drum via V-belts on variable-diameter pulleys. After washing and laundry distribution using 6 and 4 poles respectively, the motor is changed to 2-pole working which increases the speed resulting in centrifugally-actuated weights increasing the transmission ratio of the V-belt unit to achieve a high spin-drying speed. A moderate spin-drying speed may be obtained by changing back to 4-pole working, the transmission ratio remaining at the increased value. In a second embodiment (Fig. 3, not shown), a 2-4-pole motor drives the drum via planet gearing and a V-belt unit. For washing 4 poles are used and the outer ring (having helical teeth) of the planet gearing is attracted by an electromagnet so that studs thereon fit into fixed recesses to lock the ring stationary, and thus cause the planet gearing to operate in step-down mode. For laundry distribution, the motor is changed to 2-pole working. During both these operations, the motor is continually being reversed, and the magnet is deenergized to change to spin-drying speed when the motor direction is such that the helical teeth urge the outer ring to disengage the studs from the recesses and bring teeth into engagement with teeth on a member linked by a spring-biased multi-disc friction clutch to the first pulley of the V-belt unit (in which the planet wheels are also journalled). The planet gearing now has a 1:1 transmission ratio. The increase in speed causes centrifugally-actuated weights to increase the transmission ratio of the V-belt unit. A high spin-drying speed is then reached, unless the motor is changed to 4-pole working to give a moderate spin. In a third embodiment (Fig. 5, not shown), a 2-4-pole motor drives the drum through a V-belt unit, using 4,2 and 2 poles for washing, laundry distribution and high-speed spin-drying, the 2-pole speed being sufficient to cause centrifugally-actuated weights to increase the V-belt unit transmission ratio, but this being prevented during laundry distribution by a detaining pin. In a modification of this (Fig. 6, not shown) increase is not prevented but a centrifugal switch on the motor shaft controls the motor speed during laundry distribution. In a further embodiment, a 2-4-pole motor with a variable supply frequency is used.