US20040113531A1

US20040113531A1 - Dishwasher door balancing system

Info

Publication number: US20040113531A1
Application number: US10/323,048
Authority: US
Inventors: Scott Raches
Original assignee: Maytag Corp
Current assignee: Maytag Corp
Priority date: 2002-12-17
Filing date: 2002-12-17
Publication date: 2004-06-17
Also published as: CA2444320A1

Abstract

A kitchen or household appliance such as a dishwasher includes a base portion, a door hingably connected to the base portion, a cord operatively connected to the door, an extension spring operatively connected to the cord and the base portion to partially balance opening of the door by exerting a force on the cord and the door, a damping pulley positioned along the cord between the extension spring and the door to further balance opening of the door by providing resistance to motion of opening the door without manual adjustment.

Description

BACKGROUND OF THE INVENTION

This invention relates to household appliances, including, but not limited to dishwashers. More specifically, this invention relates to a system for balancing the door of the household appliance.

In household or kitchen appliances, such as dishwashers, it is desirable to have proper door balance. When there is proper door balance, the door can open in a smooth, controlled motion. It is desirable for an operator to open the door to the desired level with no sudden fall of the door or tendency for the door to spring back up from an open position. Manufacturers have attempted to provide proper door balance by manually adjusting the balance of dishwasher doors.

Adjustment of a dishwasher door is a burden to dishwasher manufacturers. Based on different model features (such as, but not limited to the control type, the presence of sound dampers, the material weight, or other variations) the weight of the dishwasher doors will vary. Therefore, in order to provide for proper balancing, each door assembly requires a specific counterbalance force to provide proper adjustment. If there is improper adjustment, a front-loading door can fall hard to a noisy and abrupt stop in the horizontal position, or the door may not sit horizontal without the operator having to physically push the door down to the fully open position. Thus, improper adjustment is a nuisance to the consumer. In particular, improper adjustment of a dishwasher door is believed to result in a poor quality perception by consumers of the dishwasher.

In dishwashers, a set of extension springs are typically used for providing proper door balance. Then, each extension spring can be manually adjusted for each dishwasher model in order to provide for proper balancing. One problem is that this adjustment process is labor-intensive, and thus can be cost prohibitive.

Another attempt is a system wherein a stranded rope runs through a groove in a fixed plastic part to generate friction for restricting door motion. One problem with such an approach is that the stranded rope can wear and break during normal use due to the wear resulting from friction. A broken rope can result in a service call.

Therefore, a primary object of the present invention is the provision of an improved household or kitchen appliance, such as a dishwasher.

A further object of the present invention is the provision of a dishwasher door that provides for proper adjustment without requiring a manual adjustment process.

A further object of the present invention is the provision of a dishwasher having a door balancing system that provides for smooth, controlled motion of the door.

Yet another object of the present invention is the provision of a dishwasher door balancing system that provides consumers with a high quality perception of the dishwasher.

A further object of the present invention is the provision of a dishwasher door balancing system that allows for variance in the weight of the dishwasher door.

Yet another object of the present invention is the provision of a dishwasher door balancing system that uses frictional force without causing undue wear on the dishwasher.

These and/or other objects, features, or advantages of the present invention will become apparent from the specification and the claims that follow.

SUMMARY OF THE INVENTION

The present invention relates to a kitchen or household appliance having a door, such as, but not limited to a dishwasher. The present invention provides for proper balancing of a dishwasher door without requiring manual adjustment of springs or other manual adjustments to compensate for the weight of the particular dishwasher door.

According to one embodiment of the present invention, a kitchen appliance includes a base portion, a door hingably connected to the base portion, a cord operatively connected to the door, an extension spring operatively connected to the cord and the base portion to partially balance opening of the door by exerting a force on the cord and the door, and a damping pulley is positioned along the cord between the extension spring and the door to further balance opening of the door by providing resistance to motion of opening the door without manual adjustment. The extension spring counterbalances most of the door weight. Then, to account for variance in door weight for different models, the damping pulley system resists motion of the opened dishwasher door. In the damping pulley system, friction is applied to resist rotation at the pulley. The present invention provides for applying the friction in various ways. Also, the pulley can include teeth to prevent the slippage of the cord. For example, a flange in operative contact with the damping pulley can provide resistance to motion of opening the door. The flange can be a piece of spring steel that engages a perimeter surface of the damping pulley. The flange can engage a side-wall of the pulley to provide resistance to motion of opening the door.

According to another aspect of the present invention, the present invention provides for a door balancing system for a dishwasher having a cabinet and a door. The door balancing system includes an extension spring operatively connected to the cabinet, a cord operatively connected to the extension spring and the door, and a pulley engaging the cord between the extension spring and the door such that the extension spring provides a first force to balance opening of the door and the pulley resists motion of opening the door to further balance opening of the door.

According to another aspect of the present invention, a front-loading dishwasher is provided. The front-loading dishwasher has a cabinet and a door operatively connected to the cabinet and includes an extension spring operatively connected to the cabinet to provide a force for partially counterbalancing weight of the door, a cord operatively connected between the extension spring and the door, a damping pulley positioned along the cord to provide resistance to motion of opening of the dishwasher door such that the door opens in a controlled manner without a manual adjustment to alter the force provided by the extension spring. The dishwasher can include a flange in operative contact with the damping pulley to increase resistance to the motion of opening the door.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of a dishwasher. [0017]
FIG. 2 is a side view of the bottom portion of a dishwasher with the door closed and having a door balancing system with a toothed pulley according to one embodiment of the present invention. [0018]
FIG. 2A is a view similar to FIG. 2, except with the door open. [0019]
FIG. 3 is a side view of a dishwasher door balancing system according to another embodiment of the present invention. [0020]
FIG. 4 is a side view of a dishwasher door balancing system according to another embodiment of the present invention. [0021]
FIG. 5 is a side view of a dishwasher balancing system according to another embodiment of the present invention. [0022]
FIG. 6 is a front view of the pulley of the door balancing system taken along lines [0023] 6-6 of FIG. 5.

DETAILED DESCRIPTION OF THE INVENTION

The present invention provides for balancing the weight of doors of a kitchen or household appliance such as a dishwasher. FIG. 1 illustrates a [0024] dishwasher 10. The dishwasher 10 includes a dishwasher door 12 and a dishwasher base portion 14. The dishwasher door 12 is hingably connected to the dishwasher base portion 14, such as along a bottom portion of the dishwasher base portion 14. The dishwasher 10 shown is a front-loading dishwasher with the door 12 opening outwardly and downwardly.
FIG. 2 provides a side view of the bottom portion of the [0025] dishwasher 10. In FIG. 2, the dishwasher door 12 is hingably connected to the dishwasher base portion 14 at the door hinge 16. A stranded rope, cable or other type of cord 18 is also operatively connected to the dishwasher door 12 in any convenient manner. For example, as shown in the drawings, the forward end of the cord 18 includes a bead or loop, which is received in a notch 32 of an inwardly extending arm 30 of the door 12. The rearward end of the cord 18 is connected to an extension spring 26 that is connected to the dishwasher base portion 14. A pulley 20 is located between the extension spring 26 and the dishwasher door 12. The cord 18 is in operative contact with the pulley 20. The pulley 20 rotates in the direction indicated by arrow 28. The pulley 20 can include a plurality of teeth 22 that may be molded into the pulley 20. The pulley 20 is pivotal about a pivot 36, which can be a shoulder bolt. The cord 18 can include catch members such as over molded beads or swaged ferrules 24 that matingly contact between the teeth 22 of the pulley 20. This restricts the motion of the cord 18 in order to reduce or eliminate slippage. Other types of catch members can be used so that the cord 18 can matingly contact with the teeth 22 of the pulley 20 in order to allow smooth opening of the dishwasher door 12.
The positioning of the [0026] cord 18 as shown allows the extension spring 26 to exert an inwardly directed force on the cord 18 to provide resistance to the motion of opening the dishwasher door 12. FIG. 2A illustrates the dishwasher door 12 in an open position with the extension spring 26 expanded.
FIG. 3 shows another embodiment of the present invention. In FIG. 3, the [0027] cord 18A is wrapped around the pulley 20. Wrapping the cord 18A completely around an outer flange 27 of the pulley 20 reduces or eliminates slippage, since there are no beads on the cord 18A.
The damping system for the [0028] pulley 20 can be provided in different manners. For example, in FIG. 4, a steel spring flange 34 is in operative contact with the pulley 20 in order to exert a friction force on the perimeter edge 27 of the pulley 20. The steel spring flange 34 can be operatively connected to the dishwasher base portion 14 with a support member 38. The steel spring flange 34 provides friction such that the pulley resists the motion of opening the door to further balance opening of the door.
Another embodiment of the present invention is shown in FIGS. 5 and 6. In FIGS. 5 and 6, a spider-like [0029] steel compression spring 44 is mounted behind pulley 20 at the pivot 36. The spring 44 has multiple legs 48, each having a substantially flat flange 42 in operative contact with a flat surface 46 of the pulley 20. This contact exerts a frictional force on the pulley 20 to smooth the motion of opening the door. In FIG. 6, the pivot 36 consists of a shoulder bolt to pivotally connect the pulley to the dishwasher tub support 40 of the dishwasher base portion 14. Although the present invention contemplates other manners of providing frictional force for providing balancing, preferably friction is not applied in a manner that will create undue wear and increase the need for servicing.
Thus, a kitchen or household appliance, such as a dishwasher, has been disclosed that has an extension spring to balance weight of the kitchen appliance door and is adapted for balancing without manual adjustment of the extension spring. The present invention contemplates that one or more extension springs and/or damping pulleys can be used. For example, the present invention contemplates that two sets of damping pulleys and extension springs can be used on opposite sides of a dishwasher. The present invention also contemplates variations and equivalents in the manner in which the pulley is dampened. These and other variations and equivalents are within the spirit and scope of the present invention. [0030]

Claims

What is claimed is:

1. A kitchen appliance, comprising:

a base portion;

a door hingably connected to the base portion;

a cord operatively connected to the door;

an extension spring operatively connected to the cord and the base portion to partially balance opening of the door by exerting a force on the cord and the door;

a damping pulley positioned along the cord between the extension spring and the door to further balance opening of the door by providing resistance to motion of opening the door without manual adjustment.

2. The kitchen appliance of claim 1 further comprising a flange in operative contact with the damping pulley to provide resistance to motion of opening the door.

3. The kitchen appliance of claim 2 wherein the flange is a spring flange for engaging a perimeter surface of the damping pulley.

4. The kitchen appliance of claim 2 wherein the flange engages a side-wall of the damping pulley.

5. The kitchen appliance of claim 1 wherein the force is an inwardly directed force.

6. The kitchen appliance of claim 1 wherein the kitchen appliance is a dishwasher.

7. The kitchen appliance of claim 1 wherein the cord is stranded.

8. The kitchen appliance of claim 1 wherein the damping pulley includes a plurality of teeth.

9. The kitchen appliance of claim 8 wherein the cord includes a plurality of catch members.

10. The kitchen appliance of claim 9 wherein the catch members are beads.

11. The kitchen appliance of claim 1 wherein the cord is wrapped completely around the pulley to reduce slippage.

12. A door balancing system for a dishwasher having a cabinet and a door, the door balancing system, comprising:

an extension spring operatively connected to the cabinet;

a cord operatively connected to the extension spring and to the door;

a pulley engaging the cord between the extension spring and the door such that the extension spring provides a first force to balance opening of the door and the pulley resists motion of opening the door to further balance opening of the door.

13. The door balancing system of claim 12 further comprising a flange in operative contact with the pulley to provide resistance to motion of opening the door.

14. The door balancing system of claim 13 wherein the flange is a spring flange for engaging a perimeter surface of the pulley.

15. The door balancing system of claim 13 wherein the flange engages a side-wall of the pulley.

16. The door balancing system of claim 12 wherein the pulley includes a plurality of teeth.

17. The door balancing system of claim 12 wherein the cord is wrapped completely around the pulley to reduce slippage.

18. A front-loading dishwasher having a cabinet and a door operatively connected to the cabinet, comprising:

an extension spring operatively connected to the cabinet to provide a force for partially counterbalancing weight of the door;

a cord operatively connected between the extension spring and the door;

a damping pulley positioned along the cord to provide resistance to motion of opening of the dishwasher door such that the door opens in a controlled manner without a manual adjustment to alter the force provided by the extension spring.

19. The dishwasher of claim 18 further comprising a flange in operative contact with the damping pulley to increase resistance to the motion of opening the door.