US3635229A

US3635229A - Selective heating system for automatic washing machine

Info

Publication number: US3635229A
Authority: US
Inventors: James W Jacobs
Original assignee: Motors Liquidation Co
Current assignee: Motors Liquidation Co
Priority date: 1970-05-19
Filing date: 1970-05-19
Publication date: 1972-01-18
Anticipated expiration: 1989-01-18

Abstract

A dishwasher having upper and lower utensil support racks and a heater element positioned adjacent each rack for preselective drying of utensils held in the racks. Manually operated selector switches are provided in electrical series with the dishwasher timer control circuit for determining which of the heaters will be operative during the washing and drying cycle.

Description

United States Patent Jacobs 1 Jan. 18, 1972 [541 SELECTIVE HEATING SYSTEM FOR 3,271,878 9/1966 Martin ..34/48 X AUTOMATIC WASHING MACHINE 3,186,417 6/1965 Fay ..l34/108 X 3,329,529 7 1967 L 4 5 [72] Inventor: James W. Jacobs, Dayton, Ohio 13 l 8 D X [73] Assignee: General Motors Corporation, Detroit, FOREIGN PATENTS OR APPLICATIONS Mich- 233,503 10/1963 Austria ..134/ss D [22] Filed: May 19, 1970 Primary ExaminerRobert L. Bleutge pp 38,750 Attamey-William s. Pettigrew, Frederick M. Ritchie and Edward P. Barthel [52] U.S.Cl. ..l34/58 D, 34/48, 134/107,

200/38 B, 219/189, 219/492, 307/141.8 [571 ABSTRACT A dishwasher having upper and lower utensil support racks 0 re and a heater element positioned ad acent each rack for 34/4548 200/38 219/492 307/1418 preselective drying of utensils held in the racks. Manually operated selector switches are provided in electrical series [56] Reerences Cited with the dishwasher tirner control circuit for determining UNITED STATES PATENTS which of the heaters will be operative during the washing and drying cycle. 3,186,418 6/1965 Stern ..134/58 D 3,064,662 1 l/ 1962 Given et al ..134/108 X 3 Claims, 2 Drawing Figures SELECTIVE HEATING SYSTEM FOR AUTOMATIC WASHING MACHINE This invention relates to dishwashers and more particularly to a selective heating arrangement for anautomatic domestic dishwasher.

With the development of the dishwashing art, it has been an objective to provide for special loads such as fine china and delicate crystal in order to make the operation of the appliance more flexible. For instance, the operator may desire to dry dishes in one of a selective number of racks and to avoid overheating and possible damage to fine china held in other racks.

Accordingly it is an object of this invention to provide a dishwasher with means for selective drying of utensils whereby special loads such as fine china may be washed in certain unheated racks to obviate the danger of their being overheated to cause damage thereto.

A further object of this invention is to provide a control circuit for programming the washing and drying cycle of an automatic dishwasher including means to preselect which of a plurality of heaters, each of which being located in heat transfer relation with an associated utensil supporting rack, is energized during the cycle.

Further objects and advantages of the present invention will be apparent from the following description, wherein a preferred embodiment of the present invention is clearly shown.

In the drawings:

FIG. 1 is a generally schematic representation of a dishwasher incorporating the invention;

FIG. 2 is a schematic wiring diagram for controlling the dishwasher in accordance with the teachings of this invention.

In accordance with this invention and with reference to FIG. '1, a dishwater is shown composed of a casing 12 enclosing a dishwashing chamber 14. The dishwashing chamber 14 is closed at the front thereof by a dishwater door (not shown) and having at the bottom thereof a depressed sump 16 leading to a water distribution system of the type taught in the commonly assigned US. Pat. No. 3,265,311 issued Aug. 9, 1966, the disclosure thereof being incorporated herein by reference.

The water distribution system of the dishwasher 10 may include a pump assembly 18 driven by the motor 20. The pump assembly 18 includes a rotatable spray arm 21 thereon to which fluid is supplied from the sump region 16 for distribution through the dishwashing chamber 14 during a cleaning cycle of the dishwasher as established by a sequence or timer control means 22 having a timer control knob 23 located on the front of an upper panel.

In general, the water distribution system includes the revolving spray arm 21 located beneath a lower utensil support rack 24 and a rotating spray column or tube 26 affixed to said spray arm and extending upwardly through a guard portion 28 of the lower rack permitting the removal of the lower rack from the dishwashing chamber. The spray tube 26 is formed with an enlarged or bulbous housing portion 30 at the top thereof having an outlet 32 aimed through an open passageway 34 formed by a central wire network on an upper utensil support rack 36. The jet stream from the outlet 32 may be aimed at a rotatable and freely rotating swirl spray impeller or wabble plate water deflector 38 above the upper rack 36. The details of one such system is shown in US. Pat. No. 3,292,645 issued Dec. 20, 1966 and assigned to the assignee of the present invention and the disclosure thereof is incorporated herein by reference. The reversible motor 20 directly drives the axial flow pump 18 in one direction in accordance with the teachings of the aforementioned US. Pat. No. 3,265,31 l to recirculate the water for washing or rinsing, and when reversed pumps the water to drain.

An annular lower heater element 40 is located below rack '24 and can be periodically energized throughout the operating cycle to provide recovery heat to the wash and rinse water and for supplying heat to the utensils in the rack 24 during the drying cycle. The lower heater 40 is retained in the cabinet by suitable securing means such as loosely mounted metal clip members generally indicated at 42 which are bolted or otherwise affixed to the side of the cabinet and allow for expansion of the heater. An upper annular heater element 44 is positioned immediately below the upper rack 36 for eating the utensils therein in a manner to be described. The upper heater 44 is preferably supported so as to be partially encased by an underlying annular troughshaped wire-mesh guard structure indicated at 46 suitably supported from the cabinet for guarding the heater 44 against contact by an operator using the lower rack or otherwise inadvertently reaching into the lower portion of the chamber. Again

suitable clips

48 and 49 may be used to secure the heater guard 46 and the heater 44 to the cabinet structure. While the heater elements can be of various wattages the preferred embodiment contemplates each

heater

40, 44 having equal outputs of approximately 500 watts when energized with a 1 15 volts 60 cycle AC power supply. A suitable blower fan (not shown) may be employed with an outside grille to blow moisture laden air from the dishwashing chamber 14 during the drying cycle as described in the US. Pat. No. 3,292,645.

The upper rack 36 may be used for cups, glasses, bowls, saucers, etc., while the lower rack 24 is adapted for receiving plates, bowls, serving dishes, pots and pans, and a silverware basket (not shown). The racks are made of heavy gauge steel wire which is coated with suitable resilient material such as white vinyl plastic. Each rack has nylon rollers indicated at 50 and 52 to allow easy movement of the

racks

24 and 36 respectively, in and out of the dishwashing chamber during loading and unloading thereof. The

nylon rollers

50, 52 glide on stainless steel glides, such as 54 for the lower rack and 56 for the upper rack, which are screw fastened to the sidewall of the washing chamber in a suitable manner. As an alternate, glides may be embossed into the sidewalls of the chamber.

As shown in FIG. 2, power from a l 15 volt power supply L,, 1. is provided for energizing the components of the control circuitry. In order to prevent operation of the dishwasher 10 with the door open, a door switch 57 is included. The sequentially operated circuitry of the dishwasher 10 is controlled by the timer 22 having a timer motor 60 which is selectively energized by a line switch 61 wherever the timer control knob 23 is depressed or pushed inwardly. The timing motor 60 is adapted to intermittently rotate a cam shaft 64 to selectively and sequentially open and close a plurality of cam-actuated switches. A solenoid-actuated fill valve 66 is selectively energized through a cam-actuated switch blade 68 to open and close the contact A for energizing a valve (not shown). The

heating elements

40 and 44 are energized from heating element contacts B and C which are opened and closed by

heater switch blades

74 and 76 actuated by the cams on the shafi 64. The push-pull switch 61 is located on one end of the axially shiftable timer shaft 80 and is closed whenever the timer motor 60 is actuated to control a dishwashing cycle.

The motor 20 includes a main run winding 82, a water distributing start winding 84 and a water draining start winding 86. A current responsive start relay 88 serves to energize the appropriate start winding in accordance with the timer selection of contacts D or E for a brief period until the motor comes up to its designed running speed and the current flow in the main winding drops off. Bypass switch 90 is operative through contacts F, G to return the timer push-pull knob 23 to its outward stop position after a full washing and drying cycle.

As mentioned above, one of the primary objects of this invention is to provide an improved heating means to achieve preselective drying without overheating of utensils such as fine china. In accordance with this object, there is provided a manually operated preselector switch 91 having individual manually operated switches 92 and 94 (FIG. 2).

Switches

92, 94 are controlled by

pushbuttons

96, 98 respectively, as seen on the control panel in FIG. 1. Referring again to FIG. 2, it can be seen that if switch 92 is closed, the operation of switch 74 will be effective to operate the heating element 40. In other words if switch 92 is closed the overall operation of the heater will be controlled by the timer switch 74. Similarly, if switch 94 is closed, the operation of the heater element 44 is dependent upon the timer cams which control the operation of switch 76. It is to be understood that the

pushbutton switches

96, 98 are of the independent type whereby the depression or release of one has no effect on the remaining pushbutton.

Referring now to H0. 2 the following selection of operations can be achieved. If it is desired to have a complete regular cycle of the dishwasher, neither

pushbuttons

96 and 98 are depressed thereby maintaining switches,92 and 94 in their nonnally closed positions. Control knob 23 is rotated slightly to a preindicated position and then depressed, whereby switch 61 is closed to energize timer motor 60. From this point on, timer motor 60 will drive the sequence control means throughout an entire cycle. The

heater elements

40 and 44 will be energized for a portion of the wash to maintain the water temperature at the desired level while during the dry period both the

heaters

40, 44 will be continuously energized.

To achieve a less intense drying action for such articles as fine china in the upper rack 36, pushbutton 98 is depressed thereby opening switch 94. With switch 94 open, the operator rotates knob 23 slightly and then depresses it until switch 61 is closed by its cam thereby energizing timer motor 60 which again will drive the sequence control means through an entire cycle. Since switch 94 is open electrical power is not provided to the upper heater element 44 but only to the lower heater element 40.

The result is a preselectable drying cycle in which only the utensils in the lower rack are subjected to intense radiant dry- I ing heat while the special load such as fine china in the upper rack is protected against overheating. Because the heater elements have approximately equal wattage outputs that are substantially less than a conventional single-heater element dishwasher the invention insures that the fine china in the upper rack will not be damaged by heat from the energized lower heater element 40.

Another option open to the operator involves depressing pushbutton 96 which opens switch 92 whereby the same operation is achieved as described above the depressing pushbutton 98 except the energization of the heater elements is reversed with upper element 44 being energized rather than lower element 40. This option could be employed to wash larger pieces of fine china or the like in the lower rack to insure against possible overheating.

It has been determined that for fine china the drying temperature should not exceed approximately 190 F. to insure that the glazed coating on the china will not develop fine cracks in the coating otherwise known as checking." By virtue of using individual low output heater elements the invention achieves a radiant heat drying arrangement wherein the radiant heat imparted to the racks does not exceed this critical temperature of 190 F. in normal operation when both

heaters

40 and 44 are energized. It should be noted that in the instant arrangement the heaters are each spaced in a horizontal plane located a distance of the order of 1% inches below the bottom of their associated

racks

24 and 36 respectively, providing an arrangement wherein this maximum temperature of 190 F. is not exceeded.

Still another option is open to the operator by depressing both pushbutton switches 96 and 98 thereby opening both

switches

92 and 94 during a presoak or rinse and hold operation wherein a partial load of dishes is rinsed but the machine is not operated at a full-washing cycle until a full load of dishes are in the machine. It is of course possible, if desired, to operate the dishwasher for a full cycle without the energization of either

heater

40 or 44.

While the embodiment of the present invention as herein described constitutes the preferred form, it is to be understood that other forms might be adapted.

What is claimed is as follows:

1. A dishwasher comprising, a casing defining a washing chamber having a sump and an access opening; a plurality of utensil supporting rack means secured to said dishwasher casing; heating means located adjacent each of said rack means; each said heating means comprising an annular heater element located in underlying relation respectively to each of said plurality of utensil supporting rack means; said heater elements each having substantially equal wattage outputs whereby said utensil supporting rack means are uniformly heated; a fill valve in fluid supply relationship to said chamber and said sump; pump means for distributing washing fluid against utensils in said rack means to be cleaned and for draining fluid from said chamber; power means for said pump means; a control circuit for said dishwasher including separate means for energizing and deenergizing each of said heating means, said fill valve and said power means; timer means for sequentially actuating said energizing and deenergizing means in a dishwashing cycle including periods of fill, wash, rinse and dry; manually operated preselectable means in electrical series circuit with certain of said timer actuated means for energizing and deenergizing said heating means whereby actuation of said manually operated preselectable means will detennine which of said heating means will be operative during the dishwashing cycle.

2. A dishwasher comprising, a casing defining a washing chamber having a sump and an access opening; upper and lower utensil supporting racks secured to said dishwasher casing; heating means located adjacent each of said racks; said heating means comprising upper and lower annular heater elements having substantially equal power outputs, said upper and lower heater elements spaced below said upper and lower utensil supporting racks respectively at a distance sufficiently close thereto to exert a radiant heat drying effect upon the utensils therein such that the radiant heat imparted to the utensils does not exceed approximately F.; a fill valve in fluid supply relationship to said chamber and said sump; pump means for distributing washing fluid against utensils in said rack means to be cleaned and for draining fluid from said chamber; power means for said pump means; a control circuit for said dishwasher including separate means for energizing and deenergizing each of said heating means, said fill valve and said power means; timer means for sequentially actuating said energizing and deenergizing means in a dishwashing cycle including periods of fill, wash, rinse and dry; manually operated preselectable means in electrical series circuit with certain of said timer actuated means for energizing and deenergizing each of said heater elements whereby actuation of said manually operated preselectable means will determine which of said heater elements will be operative during the dishwashing cycle.

3. An automatic dishwasher comprising, a casing defining a washing chamber having a sump and an access opening; upper and lower racks secured to said dishwasher casing in the upper and lower portions of said casing; said upper and lower racks for supporting utensils to be washed and dried; upper and lower annular heating elements having substantially equal power outputs of approximately 500 watts at US volts; said upper and lower heater elements spaced approximately 1% inches below their associated upper and lower racks thereby providing a radiant heat drying effect upon the utensils in each said rack which does not exceed approximately 190 F.; a fill valve in fluid supply relationship to said chamber and said sump; pump means for distributing washing fluid against the utensils to be cleaned and for draining fluid from said chamber; power means for said pump means; a control circuit for said dishwasher for sequentially controlling a dishwashing cycle including periods of fill, wash, rinse and dry; said control circuit including a timer motor, a group of cams operated by said timer motor; a group of switches operated by said cams for energizing and deenergizing said upper heater element, said lower heater element, said fill valve, and said power means; and a preselectable manually operated selector switch in electrical series with each of said timer-operated heater element switches whereby actuation of said manually operated selector switches will determine which of said timer motor operated heater element switches will be in operative relationship with the remaining timer motor operated switches during the dishwashing cycle.

Claims

1. A dishwasher comprising, a casing defining a washing chamber having a sump and an access opening; a plurality of utensil supporting rack means secured to said dishwasher casing; heating means located adjacent each of said rack means; each said heating means comprising an annular heater element located in underlying relation respectively to each of said plurality of utensil supporting rack means; said heater elements each having substantially equal wattage outputs whereby said utensil supporting rack means are uniformly heated; a fill valve in fluid supply relationship to said chamber and said sump; pump means for distributing washing fluid against utensils in said rack means to be cleaned and for draining fluid from said chamber; power means for said pump means; a control circuit for said dishwasher including separate means for energizing and deenergizing each of said heating means, said fill valve and said power means; timer means for sequentially actuating said energizing and deenergizing means in a dishwashing cycle including periods of fill, wash, rinse and dry; manually operated preselectable means in electrical series circuit with certain of said timer actuated means for energizing and deenergizing said heating means whereby actuation of said manually operated preselectable means will determine which of said heating means will be operative during the dishwashing cycle.

2. A dishwasher comprising, a casing defining a washing chamber having a sump and an access opening; upper and lower utensil supporting racks secured to said dishwasher casing; heating means located adjacent each of said racks; said heating means comprising upper and lower annular heater elements having substantially equal power outputs, said upper and lower heater elements spaced below said upper and lower utensil supporting racks respectively at a distance sufficiently close thereto to exert a radiant heat drying effect upon the utensils therein such that the radiant heat imparted to the utensils does not exceed approximately 190* F.; a fill valve in fluid supply relationship to said chamber and said sump; pump means for distributing washing fluid against utensils in said rack means to be cleaned and for draining fluid from said chamber; power means for said pump means; a control circuit for said dishwasher including separate means for energizing and deenergizing each of said heating means, said fill valve and said power means; timer means for sequentially actuating said energizing and deenergizing means in a dishwashing cycle including periods of fill, wash, rinse and dry; manually operated preselectable means in electrical series circuit with certain of said timer actuated means for energizing and deenergizing each of said heater elements whereby actuation of said manually operated preselectable means will determine which of said heater elements will be operative during the dishwashing cycle.

3. An automatic dishwasher comprising, a casing defining a washing chamber having a sump and an access opening; upper and lower racks secured to said dishwasher casing in the upper and lower portions of said casing; said upper and lower racks for supporting utensils to be washed and dried; upper and lower annular heating elements having substantially equal power outputs of approximately 500 watts at 115 volts; said upper and lower heater elements spaced approximately 1 1/2 inches below their associated upper and lower racks thereby providing a radiant heat drying effect upon the utensils in each said rack which does not exceed approximately 190* F.; a fill valve in fluid supply relationship to said chamber and said sump; pump means for distributing washing fluid against the utensils to be cleaned and for draining fluid from said chamber; power means for said pump means; a control circuit for said dishwasher for sequentially controlling a dishwashing cycle including periods of fill, wash, rinse and dry; said control circuit including a timer motor, a group of cams operated by said timer motor; a group of switches operated by said cams for energizing and deenergizing said upper heater element, said lower heater element, said fill valve, and said power means; and a preselectable manually operated selector switch in electrical series with each of said timer-operated heater element switches whereby actuation of said manually operated selector switches will determine which of said timer motor operated heater element switches will be in operative relationship with the remaining timer motor operated switches during the dishwashing cycle.