Title:
Washing machine with pumping damper for automatic balancing
Kind Code:
A1


Abstract:
An improved washing machine includes a tub with a rotatable drum mounted therein, in either a horizontal or vertical orientation. An open balance ring is mounted on the drum. The tub is supported by a damper which pumps fluid to the balance ring to counter balance unbalanced loads in the drum during dynamic operation of the machine.



Inventors:
Cummings, Stephan A. (Wilsonville, OR, US)
Application Number:
11/108491
Publication Date:
10/19/2006
Filing Date:
04/18/2005
Assignee:
Maytag Corporation (Newton, IA, US)
Primary Class:
Other Classes:
68/12.06, 68/23.1, 68/23.2
International Classes:
D06F33/00; D06F35/00
View Patent Images:



Primary Examiner:
STINSON, FRANKIE L
Attorney, Agent or Firm:
MCKEE, VOORHEES & SEASE, P.L.C. (DES MOINES, IA, US)
Claims:
What is claimed is:

1. A washing machine, comprising: a cabinet; a tub mounted in the cabinet; a damper to mount the tub in the cabinet; a drum rotatably mounted in the tub; a balance ring on the drum; a fluid line extending from the damper; and the damper being adapted to pump fluid through the fluid line and into the balance ring to counter-balance an unbalanced load in the drum.

2. The washing machine of claim 1 wherein the balance ring is open.

3. The washing machine of claim 1 wherein the damper is a piston and cylinder assembly.

4. The washing machine of claim 1 further comprising a fluid source operatively connected to the fluid line.

5. The washing machine of claim 1 wherein the fluid line includes a one-way valve to control fluid flow through the line.

6. The washing machine of claim 1 wherein the balance ring extends 360° around the drum.

7. The washing machine of claim 6 wherein the balance ring has internal walls to define a plurality of compartments.

8. The washing machine of claim 6 wherein the balance ring includes an opening for receiving fluid from the fluid line.

9. The washing machine of claim 8 wherein the opening is a slot extending 360° around the balance ring.

10. The washing machine of claim 9 wherein the slot is on an inner peripheral wall of the balance ring.

11. The washing machine of claim 1 wherein the fluid line terminates in a spray nozzle adjacent the balance ring.

12. A method of automatically balancing an unbalanced load in a washing machine, the washing machine having a drum rotatably mounted in a tub supported by dampers within a cabinet, and a balance ring on the drum, the method comprising: pumping fluid from one of the dampers to the balance ring when the load is unbalanced.

13. The method of claim 12 wherein the pumping is during a dynamic cycle of the washing machine.

14. The method of claim 12 wherein the pumping is during a spin cycle of the drum.

15. The method of claim 12 further comprising spraying the fluid into the balance ring.

16. The method of claim 12 further comprising controlling fluid flow between the one damper and the balance ring with a one-way valve.

17. An improved washing machine having a tub with a rotatable drum therein, and with an open balance ring on the drum, the improvement comprising: a pumping damper connected to the tub to pump fluid to the balance ring to counter-balance unbalanced loads in the drum.

18. The improved washing machine of claim 17 wherein the damper includes a cylinder and piston assembly.

19. The improved washing machine of claim 17 further comprising a fluid line extending from the damper to the balance ring.

20. The improved washing machine of claim 17 wherein the fluid line includes a spray nozzle for spraying fluid into the balance ring.

Description:

BACKGROUND OF THE INVENTION

Clothes washing machines commonly are provided with a fluid ring to correct or counter balance unbalanced loads during the spin operations. The fluid rings are normally mounted at the top edge of a vertical axis drum or the front edge of a horizontal axis drum. Balance rings are also known to have been provided along the side wall of a vertical axis drum and the rear wall of a horizontal axis drum.

Such fluid balance rings are effective at high rotational speeds to counter balance the unbalanced loads resulting from objects in the drum being unevenly distributed or off-center. An example of such a situation is a load of towels positioned along one side of the rotating washing machine drum, which creates an unbalance. Such an unbalanced condition causes deflections in the rotating drum. The deflection of the unbalanced drum increases as the rotational speed of the drum increases, up to a critical speed, after which the deflections are minimized by the function of the fluid balance ring. The critical rotational speed varies from assembly to assembly, depending on the structure, mass, and geometry of the rotating assembly and its contents. The fluid within the balance ring counteracts the unbalanced load in the drum when the drum is rotating at high speeds.

Washing machine suspensions typically have a very robust design to allow the dynamic system to carry large unbalances to a water extraction speed. It is desirable to limit the displacement of the dynamic assembly. Prior art efforts to limit the displacement include tumbling of the laundry to redistribute the load, use of a sealed dynamic fluid balance ring, use of large concentric rings to lower the critical frequency of the dynamic assembly, and dynamic balancing by adding fluid to the appropriate sections of an open balance ring. Closed or sealed balance rings add weight to the washing machine, which is unnecessary until there is an unbalanced load. Also, a closed balance ring has a fixed weight, which may be too much or too little. Prior art open balance rings typically include sensors to detect when the unbalanced condition is corrected or overcome so that the drum can be ramped up to full rotation speed.

Accordingly, a primary objective of the present invention is the provision of an improved washing machine having a pumping damper to automatically counter balance an unbalanced load in the rotating drum.

Another objective of the present invention is the provision of a washing machine having an open balance ring for receiving a balancing fluid when there is an unbalanced load in the drum.

A further objective of the present invention is the provision of a washing machine having an open balance ring without sensors.

Still another objective of the present invention is the provision of a method of automatically balancing an unbalanced load in a washing machine.

Yet another objective of the present invention is the provision of a method for pumping fluid from a tub damper to a balance ring when there is an unbalanced load in the drum.

A further objective of the present invention is the provision of a washing machine with a balance ring that quickly and effectively adjusts to balance loads in the washing machine drum.

These and other objectives become apparent from the following description of the invention.

SUMMARY OF THE INVENTION

The washing machine comprises a cabinet and tub mounted within the cabinet. The tub is supported by a plurality of dampers, with a drum rotatably mounted within the tub. The drum includes an open balance ring. A fluid line extends from a damper to a spray nozzle adjacent the balance ring. The dampers are adapted to pump fluid to the balance ring to counter balance an unbalanced load in the drum.

In the method of the present invention, an unbalanced load in the washing machine is automatically balanced by a pumping damper which pumps fluid from the damper to the balance ring when the load is unbalanced during a dynamic cycle of the washing machine. Fluid is sprayed into the open balance ring during the dynamic cycle, and is drained from the balance ring when the cycle is completed.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a side schematic view of the automatic balancing system of the present invention, as used on a vertical axis washing machine, with the rotating drum being in a balanced state.

FIG. 2 is a view similar to FIG. 1 showing the drum in an unbalanced state.

FIG. 3 is an enlarged perspective view of the washing machine drum, with the spray nozzle and open balance ring of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

A washing machine is generally designated in the drawings by the reference numeral 10. The washing machine 10 includes a tub 12 with a drum 14 rotatably mounted therein. For clarity, the motor and drive shaft for the drum 14 are not shown in the drawings. The upper end of the drum 14 includes an open balance ring 16. The balance ring 16 extends around the perimeter of the drum 14 and includes an internal annular slot 18. The balance ring 16 includes internal walls so as to define compartments therein. At least one drain opening (not shown) is provided in the ring 16.

The tub 12 is supported by a plurality of dampers 20. Preferably, each damper 20 is comprised of a piston 22 and a cylinder 24 which form an assembly extending between the tub and the base of the washing machine 10. The number of dampers depend on the machine. Vertical axis washers often have four dampers spaced substantially equally about the tub 12, while horizontal washers may have only two dampers to support the tub.

One of the dampers 20 includes a fluid line 26 extending from the cylinder 24 to a position adjacent the balance ring 16. The fluid line 26 terminates in a spray nozzle 28 mounted in a fixed position, such as on the tub 12, and directed so as to spray fluid from the cylinder 24 into the slot 18 of the balance ring, as described below. A fluid supply tank or reservoir 30 is operatively connected to the fluid line 26 so as to replenish the fluid in the cylinder 24. The reservoir 30 is replenished with fluid from the tub 12. One way valves 32 are provided in the fluid line 26 to prevent backflow of fluid.

In operation, when there is a balanced load in the drum 14, the dampers 20 are balanced and the balance ring 16 is empty of fluid. The balance state of the washing machine 10 is shown in FIG. 1. When an unbalanced condition exists in the drum 14, the tub and drum 14 tilt to the over-loaded side, as shown in FIG. 2. As the drum rotates, the heavy tilted side causes the damper 20 to compress and thereby pump fluid through the fluid line 26 and out the nozzle 28 into the slot 18 of the balance ring 16 opposite the compressed damper 20. As the drum 14 rotates, such as during a spin cycle, the damper 20 pumps the fluid in a pulsating manner, drawing fluid from the reservoir 30 so as to be sprayed into the balance ring segment opposite the unbalanced load.

As the drum 14 becomes more balanced through the fluid in the balance ring 16, the displacement of the dynamic system will no longer be of sufficient magnitude to cause the damper 20 to spray fluid into the balance ring 16. When the spin cycle ends, the drum 14 will coast to a stop and all the fluid in the balance ring 16 will drain, leaving the system ready for the next run.

While the drawings show the pumping dampers 20 utilized on a vertical axis washing machine, it is understood that similar dampers may be utilized on a horizontal axis washing machine, which will operate in a similar manner as described above so as to pump fluid from the cylinder 24 to a balance ring when the drum is in a unbalanced dynamic state.

The invention has been shown and described above with the preferred embodiments, and it is understood that many modifications, substitutions, and additions may be made which are within the intended spirit and scope of the invention. From the foregoing, it can be seen that the present invention accomplishes at least all of its stated objectives.