Patent US3911943A successfully refreshed from Google Patents.
US3911943A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Control circuit for dishwasher
Assignee: Hobart Corp
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Filing: 1974-10-25
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Granted: 1975-10-14
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Expires: 1994-10-25
Abstract
Abstract An electrical circuit for controlling various functions in a plurality of dishwashers having common features of a washing chamber containing a quantity of washing solution, means for heating the washing solution, a temperature sensor arranged to respond to the temperature of the solution, a pump for circulating washing solution through a spray head, and an electric motor for driving the pump. The control circuit includes a plurality of circuit boards for controlling the sequence of operation of the dishwasher, overheating protection for the pump motor, and the means for heating the washing solution. Many circuit boards contain indicating lamps in the form of light emitting diodes to indicate proper operation of the circuit. Other circuit boards include optional features, such as automatic initiation of the washing cycle upon the closure of the door.
Inventors
- 👤 Stuart E Athey
- 👤 Alan Lee Vore
- 👤 Donald E Swihart
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 15:46
CPC Classifications
A; A47; A47L; A47L15/00; A47L15/42; A47L15/4297; Y; Y10; Y10T; Y10T137/00; Y10T137/6416; Y10T137/6606; Y10T137/8593; Y10T137/85978
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
138 words
In a dishwasher including means including an electric motor operated pump for recirculating washing liquid over articles placed in the dishwasher, a storage tank for supplying heated washing liquid to said pump, and means for heating the washing liquid in said storage tank, the improvement comprising, in combination, first temperature responsive resistance means in thermal relation to said motor and first electronic circuit means responsive to the resistance of said first temperature responsive means for interrupting the flow of electrical current to said motor when the motor temperature increases above a predetermined level, and second temperature responsive resistance means in thermal contact with the liquid in said storage tank and second electronic circuit means responsive to the resistance of said second temperature responsive means for controlling said heating means to maintain said liquid at a predetermined elevated temperature.
Claim 2
Dependent Claim
138 words
In a dishwasher including means including an electric motor operated pump for recirculating washing liquid over articles placed in the dishwasher, a storage tank for supplying heated washing liquid to said pump, and means for heating the washing liquid in said storage tank, the improvement comprising, in combination, first temperature responsive resistance means in thermal relation to said motor and first electronic circuit means responsive to the resistance of said first temperature responsive means for interrupting the flow of electrical current to said motor when the motor temperature increases above a predetermined level, and second temperature responsive resistance means in thermal contact with the liquid in said storage tank and second electronic circuit means responsive to the resistance of said second temperature responsive means for controlling said heating means to maintain said liquid at a predetermined elevated temperature.
Claim 3
Dependent Claim
82 words
The dishwasher of claim 1 further including liquid level sensing means for indicating when the level of washing liquid in said storage tank falls below a predetermined level, circuit responsive means to said sensing means to disconnect said heating means during low water level conditions, and time delay means connected to the output of said liquid level sensing means to prevent an indication of low liquid level during momentary fluctuations in said liquid level of sufficient magnitude to actuate said sensing means.
Claim 4
Dependent Claim
26 words
The dishwasher of claim 1 further including means for indicating visually when the current to said motor is interrupted by reason of an over temperature condition.
Claim 5
Dependent Claim
26 words
The dishwasher of claim 1 further including means for indicating visually when said heating means is supplying heat to the washing liquid in said storage tank.
Claim 6
Dependent Claim
26 words
The dishwasher of claim 1 further including means for interrupting the current to said motor in the event said first temperature responsive means becomes open circuited.
Claim 7
Dependent Claim
24 words
The dishwasher of claim 1 further including means for disconnecting said heating means in the event said second temperature responsive means becomes open circuited.
References Cited (Backward Citations)
US2692604A
Cited
US2975347A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1978-10-13 | 1979-04-14 | 1979-10-14 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-10-13 | 1983-04-14 | 1983-10-14 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-10-13 | 1987-04-14 | 1987-10-14 | $7700.00 | Window Closed / Lapsed |