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PATENT:
SELF-EQUILIBRATING DRUM FOR WASHING MACHINES 
Filed in Italy on 18/11/2008, N° N° TO 2008 A 000848
vittorio.scialla@strumentiperleaziende.com
ABSTRACT
A toroidal bag (11) made of elastomer, provided with protuberances (13) oriented towards its rotation axis, filled with a liquid fluid, and secured inside a drum of a washing machine.
During a washing phase, said protuberances drag the clothes load.
During a spin drying phase, the liquid contained in said toroidal bag, by effect of centrifugal force, tends to dilate and to flatten said protuberances (22), so that said toroidal bag tends to level itself into a cylindrical "water bed".
The heaviest parts of a clothes load (23) tend to sink in said "water bed" (24), and displace a mass of liquid equal to their unbalance, which redistributes itself under the lighter parts of the load. The radial force exerted over the drum will result to be uniform along all of its perimeter and the drum on the whole will result to be balanced

CHARACTERISTICS

The disclosed self-equilibrating drum allows to eliminate the complex inertial system, used in current washing machines, which includes heavy counterweights connected to the tub in order to reduce the unbalance, and suspensions, made of one or more springs and one or more dampers, which allow the tub to oscillate around its barycentre, while preventing it to resonate at its characteristic frequency.
The significant weight reduction which may be obtained by the elimination of said counterweights, allows to reduce the cost of shipping and installation, allowing a single installer to install it, even when it is needed to bring it over one or more floors by manual means.

PATENT (pdf)