1. Field of the Invention
This invention relates generally to a balancer for dehydration tubs for use in washing machines or the like, and more particularly to such a balancer of the liquid-in-container type including a concentric multi-compartment container.
2. Description of the Prior Art
In dehydration tubs used in washing machines having a centrifugal dehydrating function or the like, a liquid-in-container type balancer is mounted on an upper open end of the dehydration tub for the purpose of correcting an unbalanced condition thereof due to one-sided laundry. For improvement in a correcting force, the interior of the balancer is divided by one or more vertically extending concentric partition walls into a plurality of compartments. A predetermined amount of liquid (usually, salt water) is contained in each of the compartments.
FIGS. 23 and 24 illustrate the construction of a conventional balancer of the type described above. Referring to FIG. 24, the balancer comprises an annular balancer container 1 having in its interior a partition wall 2 standing from the bottom thereof. The interior of the container 1 is divided by the partition wall 2 into inner and outer compartments 3 and 4. A lid 5 is attached to the top of the container 1 so as to close upper openings of the compartments 3 and 4. The lid 5 has two inlets 6 and 7 formed therein to correspond to the compartments 3 and 4 respectively. A liquid 8 is poured through the inlets 6 and 7 into the respective compartments 3 and 4. Thereafter, closures 9 and 10 are closely fitted into the inlets 6 and 7 respectively.
In the balancer described above, the liquid 8 contained in the container 1 leaks out or flows between the compartments 3 and 4 if the compartments are not watertightly sealed by the lid 5 or if the inlets 6 and 7 are not watertightly closed by the respective closures 9 and 10. Consequently, an expected correcting force cannot be obtained when the liquid 8 leaks out of the container 1 or flows between the compartments 3 and 4. In view of this problem, watertight tests need to be carried out for the balancer.
The watertight tests are carried out in the following procedure. The interior of the compartment 3 is pressurized or depressurized through the inlet 6 after the lid 5 has been attached to the container 1. Consequently, the watertightness is tested at a boundary 11 between an inner wall of the container 1 and the lid 5 and at a boundary 12 between the partition wall 2 and the lid 5. Subsequently, the interior of the compartment 4 is pressurized or depressurized through, the inlet 7 in order that the watertightness is tested at a boundary 13 between an outer wall of the container 1 and the lid 5. Finally, the inlets 6 and 7 are closed by the respective closures 9 and 10 after the liquid 8 has been poured into the compartments 3 and 4 through the inlets respectively. The completed balancer is then put into a chamber, and the interior of the chamber is pressurized or depressurized in order that the watertightness at boundaries between the circumferential edges of the inlets 6 and 7 and the closures 9 and 10 is tested.
In the conventional balancer, the watertight test needs to be carried out for each of the compartments 3 and 4, and furthermore, the other watertight test needs to be carried out at a stage of the end product of balancer. Accordingly, steps of the watertight test is increased with an increase in the number of compartments of the container. Furthermore, since the portions of the balancer to be tested are diverse, an equipment for the watertight test is rendered complicate, and accordingly, the cost of equipment is increased.
On the other hand, the number of compartments of the container or the height of the balancer is increased in the prior art so that the performance of the balancer is improved. In each case, the size of the balancer is increased, which results in an increase in the size of the washing machine or a decrease in a washing capacity of the washing machine.
Furthermore, the correcting performance of the balancer mainly depends upon the configuration of the container 1. The correcting performance of the balancer cannot be altered after its configuration has been determined.