Dishwasher overfill protection device

• US 5,018,550 A
• Filed: 10/19/1990
• Issued: 05/28/1991
• Est. Priority Date: 10/19/1990
• Status: Expired due to Term

• Current Assignee: Whirlpool Corporation
• Original Assignee: Whirlpool Corporation
• Inventors: Burdorff, Mark A.
• Primary Examiner(s): Walton, George L.
• Application Number:
  US07/599,990
• Time in Patent Office: 221 Days
• Field of Search: 73/322.5, 73/306, 73/309, 134/57 D, 134/58 D, 137/387, 137/412, 137/413, 137/429, 137/430, 68/207, 68/208, 200/83 WM, 200/84 R
• US Class Current: 137/387
• CPC Class Codes: H01H 35/18 Switches operated by change of liquid level or of liquid density, e.g. float switch by magnet carried on a float H01H36/02
• CPC Class Codes: Y10T 137/729 Washing machine cycle control
• CPC Class Codes: Y10T 137/7368 Servo relay operation of control
• CPC Class Codes: Y10T 137/7423 Rectilinearly traveling float

Abstract

A dishwasher is provided with an improved apparatus for protecting the tub from being overfilled in the form of a float having a float stem that is automatically captured upon insertion through a passage in the tub bottom wall such that the float will be restrained against disengagement from the tub bottom wall. The float is vertically movable to operate a control switch for regulating the level of water within the tub. Preferably a retaining ring is carried on a stem of the float which is automatically biased through a varying diameter keyway and is subsequently moved to a captured position below the member having the keyway.

Claims

1. In a dishwasher having a tub with a bottom wall, means for introducing water into said tub and switch means for controlling said means for introducing water into said tub, an improved apparatus for protecting said tub from being overfilled by water, said improvement comprising:

a passage extending through said tub bottom wall, said passage including an open top and bottom end,

a float positioned in said passage including a float body for responding to water level within said tub and a retainer means adjacent a stem secured to said float body, said stem having a retainer means adjacent a bottom end terminating below said tub bottom wall, said stem being operatively engageable with said switch means,

restraining means located beneath said tub bottom wall for restraining upward movement of said float,

means associated with said restraining means and said float retainer means for causing automatic captured engagement of said retainer means with said restraining means upon a sufficient downward insertion movement of said stem relative to said restraining means and thereafter preventing disengagement of said stem from said restraining means by said retainer means upon a predetermined amount of relative upward movement of said stem during normal operation of said float in relationship to said switch means.

2. A dishwasher according to claim 1, wherein said passage is defined by a standpipe formed in said bottom wall of said tub.

3. A dishwasher according to claim 2, wherein said float body has an interior diameter greater than a diameter of said standpipe.

4. A dishwasher according to claim 1, wherein said restraining means comprises means fixed relative to said dishwasher tub secured below said tub bottom wall for effecting captured engagement with said stem retainer means.

5. A dishwasher according to claim 4, wherein said retainer means on said float stem comprises a detent shape engageable with said restraining means fixed relative to said dishwasher tub.

6. A dishwasher according to claim 5, wherein said detent shape comprises an enlarged diameter ring positioned at a lower end of said float stem.

7. A dishwasher according to claim 4, wherein said restraining means fixed relative to said dishwasher tub comprises a detent shape configured to capture said retainer means on said float stem.

8. A dishwasher according to claim 7, wherein said capturing detent comprises a keyway having an enlarged opening area for receiving said retainer means on said float stem and a reduced diameter area for preventing disengagement of said retainer means on said float stem from said keyway, said restraining means further comprising means for directing said retainer means on said float stem toward said enlarged diameter portion of said keyway during insertion of said float stem relative to said restraining means and means for moving said retainer means on said float stem toward said reduced diameter area of said keyway following passage of said retainer means on said float stem through said keyway.

9. A dishwasher according to claim 8, wherein said means for directing said retainer means on said float stem toward said large diameter of said keyway comprises a wall surface obtusely angled relative to a direction of said insertion, said wall surfaces angled toward said enlarged diameter opening of said keyway.

10. A dishwasher according to claim 8, wherein said means for moving said float stem toward said small diameter portion of said keyway comprise said float stem being resilient and said small diameter portion being positioned coaxially with said passageway receiving said float stem.

11. In a dishwasher having a tub means for introducing water into said tub and switch means for controlling said means for introducing water into said tub, an improved apparatus for protecting said tub from being overfilled by water, said improvement comprising:

a standpipe extending into said tub from a lower wall thereof, said standpipe having a wall defining a passageway having open ends, one end being secured to said lower tub wall,

a float, said float including a float body for responding to water height within said tub, and a float stem extending from said float body through said standpipe, said float stem having an upper end and a lower end, said upper end being secured to said float body and said lower end terminating at a point beyond said tub wall and said standpipe,

said float stem lower end including a radially extending retainer,

securing means located beneath said lower tub wall for securing said float stem to said dishwasher, said securing means including a keyway through which said float stem extends, said keyway including a widened portion permitting passage of said retainer therethrough and a narrowed portion restricting passage of said retainer therethrough, said narrowed portion of said keyway being aligned coaxially with said standpipe,

a wall surface about said narrowed portion of said keyway angled toward said widened portion of said keyway for deflecting said float stem and directing said retainer through said widened portion when said float stem is inserted into said standpipe, whereby upward movement of said float stem is limited by said retainer engaging said securing means during normal operation of said float in relationship to said switch means.

12. A dishwasher as claimed in claim 11, wherein said switching means further includes housing means at least partially enclosing said switching means, and said guide means for said float stem being formed integral with said housing means.

13. A dishwasher as claimed in claim 11, wherein said wall surface comprises a top surface of a pair of spaced upstanding walls extending toward said standpipe from beneath said lower tub wall, said upstanding walls being spaced at a distance less than a diameter of said retainer.

14. A dishwasher as claimed in claim 13, wherein said pair of spaced upstanding walls are integral to said securing means.

15. In a dishwasher having a tub with a bottom wall, means for introducing water into said tub and switch means for controlling said means for introducing water into said tub, an improved apparatus for protecting said tub from being overfilled by water, said improvement comprising:

a passage extending through said tub bottom wall, said passage including an open top and bottom end,

a float positioned in said passage including a float body for responding to water level within said tub and a stem secured to said float body, said stem having a bottom end terminating below said tub bottom wall operatively engageable with said switch means,

a first detent fixedly positioned below said tub bottom wall,

a second detent carried on said float stem,

means associated with said detents for causing automatic captured interengagement between said detents after insertion of said float stem through said open bottom end of said passage and during normal operation of said float in relationship to said switch means.

16. A dishwasher according to claim 15, wherein said second detent comprises an enlarged diameter ring positioned near a bottom end of said float stem.

17. A dishwasher according to claim 16, wherein said first detent comprises a keyway with a narrow opening, smaller than said enlarged diameter ring positioned coaxially below said passage, and a wider opening, larger than said enlarged diameter ring laterally spaced from an axis of said passage, and said means comprises a wall surface obtusely angled relative to an insertion direction of said float stem along said axis, said wall surface engaging and guiding said ring toward said wider opening upon insertion of said float stem, said float stem being flexible and resilient so as to return to a coaxial position, relative to said passage, after said ring has passed through said opening.