US2701574A - Dishwasher or the like - Google Patents

Description

Feb. 8, 1955 c. HOLLERITH 2,

DISHWASHER 0R THE-LIKE s sheeis-sheetl Filed May 1, 1953 v INVENTOR. (/JARLES HOLLE/Z/Th A TTOR NEY Feb. 8, 1955 Filed May 1, 1953 C. HOLLERITH DISHWASHER OR THE LIKE 3 Sheets-Sheet 2 JNVENTOR. //01 1. 5/2/ 77/ ATTO/P/VE Y Feb. 8, 1955 Filed May 1, 1953 C. HOLLERITH DISHWASHER OR THE LIKE 3 SheetsSheet 3 I N V EN TOR LHARLEJ HOLLER/TH A TTQR/VEY United States Patent DISHWASHER OR THE LIKE Charles Hollerith, Jackson, Mich., assignor, by mesne assignments, to The Apex Electrical Manufacturing Company, Cleveland, Ohio, a corporation of Ohio Application May 1, 1953, Serial No. 352,347

2 Claims. (Cl. 134-57) lating system for delivering liquid to the machine vat under pressure and returning said liquid to the pump for recirculation is provided w th means for mll'llIIllZlng noise created by liquid pulsations emanatmg from the pump and vibrations, primarily torsional, occurring in the motor-pump unit. It is well known that in dish washing machines of the above type, the pump creates l1qu1d pulsations in the conduit extending from the pump to the vat, and since the vat acts like a sounding board to some degree, considerable undesirable noise is created. I provide a relatively long conduit or hose formed of soft rubber and extending between the pump and vat, and the expansion and contraction of the hose largely damps or smoothes out the pulsations before reaching the vat. Further, vibrations, primarily torsional, occur in the motor-pump unit and if such vibrations are directly transmitted to the machine, the noise level is substantially increased. I provide a resilient mounting for the motorpump unit and have found that this type mounting coupled with the long and expansible water passage between the pump and vat results in a relatively quiet operating dishwasher.

It is a primary object of the invention to provide in a dishwashing machine having a liquid circulating system,

including a pump, means for minimizing transmission of I vibration and resultant noise during circulation of liquid.

Another object of the invention is to provide in a dishwashing machine of the above type having a built-in heater tank, a relatively simple liquid supply, circulating and drainage system.

Another object of the invention is to provide a dishwashing machine of the above type having a built-in heater tank disposed beneath the article receiving vat adapted to be gravity filled and having associated means for lifting the water from the heater tank into the article receiving vat.

Other objects of the invention and the invention itself will become increasingly apparent from a consideration of the following description and drawings, wherein:

Figure l is an elevational view, partially in section,

and with parts omitted for clearness of illustration, of a dishwashing machine embodying the invention;

Figure 2 is a longitudinal, sectional view of a heater tank I may employ;

Figure 3 is a sectional view of a cam operated valve means I may employ;

Figure 4 is a view of a timer and valve means I may p y;

Figure 5 is a side elevational view showing the mounting means for the motor-pump unit;

Figure 6 is an end elevational view of the unit shown in Fig. 5; and

Figure 7 is a wiring diagram showing a preferred electrical hook-up for the dishwasher.

Referring now to the drawings, and particularly Figure l, I have indicated the dishwasher vat or tub at 10.

Patented Feb. 8, 1955 The vat or tub 10 has a hinged lid (not shown) with an associated safety switch 10' (Figure 7). The vat base 11 is formed to drain to a sump 12 which through a conduit 13 connects with a pump 14 driven by an electric motor The pump is preferably of the type having a twobladed impeller working in a water-tight chamber wherein liquid is received through an axial inlet- 17 and discharged undervpressure from a tangential outlet 18. A Venturi fitting 19 connects conduit 13 and pump inlet 17, the Venturi fitting having a relatively reduced lateral inlet port communicating with a conduit 21 extending from an inlet valve 22 which forms part of a timer and valve assembly generally indicated at 23.

A second conduit 24 extends to the inlet valve from a heater tank 26. At the opposite or upper end of assembly 23 is a drain valve 27 having a relatively long drain hose 28 terminating in a hook portion 29 adapted to be hooked over the edge of a sink, set tub or the like. A conduit 31 also extends from the drain valve to a T fitting 32 connected to the outlet 18 of the pump. A relatively long and preferably looped conduit 33 formed of relatively soft rubber extends from fitting 32 to a fitting 34 sealed to the base of vat 10 and forming a swivel mounting for a spinner arm 36 within the vat. Arm 36 is provided with a plurality of jet nozzles 37 whereby when water is supplied under pressure to arm 36, the arm will be caused to rotate by the reaction of water jets issuing from the nozzles. Depending blades 38 limit the speed of rotation of arm 36 when operating in liquid.

The heater tank 26, suitably insulated, has a cup form body 39 and a head 41 sealingly secured thereto. A U form electric immersion heater 42 is adapted to heat or maintain liquid in the tank at a predetermined temperature and a float type safety switch 43 is adapted to prevent the heater circuit from being energized unless there is water in the tank to a predetermined level. The tank is filled through a hose 44 having a bulb'type connector 46 for engagement with a faucet. The connector 46 is forced over the faucet spout and is resilient to be adaptable to various shapes of faucet spouts, and since the tank is filled by gravity, there is little pressure at the faucet connection. When the tank is filled, water overflows through a conduit 47 into a cup 48 encasing an opening in the vat side wall whereby water flowing into the vat 10 indicates that the heater tank 26 is filled. This arrangement provides a vacuum break preventing reverse flow of water from the vat back into the tank. A thermostat 49 is mounted in the top zone of tank 26 for a purpose to be described. Thermostat 49 is connected with a float switch 49' (Figure 7) operating in the heater tank 26 and the purpose of which float switch is to close the timer motor circuit when the water level in the heater tank falls to a predetermined level.

The drain valve 27 is best illustrated in Figure 3 and comprises a cast metal housing 51 having a lateral extension or sleeve 52 for connection with drain hose 28 and a second sleeve 53 for connection with conduit 31. The upper portion of the housing is sealed by a removable plug 54 which forms a seat for one end of a compression spring 56, the lower or other end of the spring bearing against the stem of a valve 57 and tends to hold the valve against the seat 58. The lower portion of the valve stem is slidable in the vertical portion of the housing 51 and an O ring type seal 59 prevents leakage therebetween. The valve stem at its lower portion is forked to ride at either side of a cam disc 66 and to receive a cam roller 62. A conventional timer electric motor 63 rotates the cam shaft 65 whereby when the lift portion 64 of the cam engages roller 62, the valve 57 will be lifted from its seat 58 permitting water to flow from conduit 31 to drain hose 28. The inlet valve 22 is similarly constructed and is operated by'a second cam 61 whereby when this valve is open water will flow from conduit 24 to conduit 21. A third cam 67 is adapted to break the circuit to the timer motor at the completion of the cycle.

The manual control knob, indicated at in Fig. 4, can be operated to rotate cam 88' which will close switch 88 and condition the circuits of the timer motor 63 and heater 42 for energization. Thereafter if the lid safety switch 10 is closed the timer motor will operate if either the thermostatic switch 49 or the thermostat float switch 81 encircle rods 79 If there is insuflicient water 49' is closed and the heater 42 will be energized if the heater float switch 43 is closed, assuming the timer motor is operating due to closure of switch 49 and the pump is operating to draw water from heater tank 26. Under these conditions it the thermostat should cool or switch 49 should open for any reason the circuit to the timer motor 63 would be broken and the machine would continue to operate indefinitely, unless some arrangement is provided for having the timer complete the cycle. The float switch 49' accomplishes this result since when a predetermined low water level in the heater tank 26 is reached, switch 49' closes to place the timer motor in circuit to complete the cycle.

Referring now to Figures and 6, the manner in which the motor-pump unit is mounted will now be explained. The parts illustrated in Figure 1 are encased in a cabinet (not shown) and a pair of angle members 71 are secured in any suitable manner to the cabinet frame structure to provide a rigid support. A pair of L section plates 72 are secured to the housing of motor 16 by bolts 73. The plates 72 have an upper portion conforming in contour to the motor housing and a horizontally extending portion provided with spaced holes. Step form, perforated, cup shaped elements 76 have the section of reduced diameter projected through the holes and the enlarged lower portion which abuts plates 72 forms a seat for the upper end of springs 77. Cup members 78, which rest on members 71, form seats for the lower ends of springs 77. Rods 79, preferably formed of hexagonal stock, have a reduced threaded section at each end forming shoulders against which lower cup members 78 and similar upper cup members abut. Upper springs with the lower ends of the springs seating on the horizontal portion of plates 72 and the reduced diameter section of cup elements 76 projecting upwardly within the lower convolutions of springs 81 to limit lateral movement of the springs. Lock washers 82 and nuts 83 threaded to rods 79 hold the lower ends of the rods and lower cup members 78 in firm engagement with members 71 and the upper cup members 78 in firm engagement with the upper end of the rods. The lower springs 77 which take the load of the motor-pump unit have a higher rating or are relatively stronger than the upper springs 81 which serve to dampen vibrations. The hexagonal rods 79 pass through openings 76' in re-' duced upper portions of the cup elements 76 with all round clearance, whereby to permit the motor-pump unit to partake of limited horizontal floating movement. It will be noted that the springs are outboard of the motor or spaced some distance from the vertical center line of the motor which increases their effectiveness in damping torsional vibration. For example, if the ngotor tends to rotate in a given direction, this tendency is yieldingly resisted by one lower spring 77 and the opposite upper spring 81. It is desirable that the lower springs 77 have as low a rating as possible consistent with their ability to support the motor-pump unit.

The operation of the dishwashing machine will now be described with reference to the wiring diagram illustrated in Figure 7. The bulb connector 46 is secured to the spout of a house hot water faucet, and when the faucet is turned on, hot water flows into heater tank 26 until it overflows into vat indicating the heater tank is full. Power leads are indicated at 86 and 87. With the lid safety switch 10' closed, if switch 88 is closed by rotating cam 88' through manual control knob 90 the heater 42 is energized and timer motor 63 is placed in circuit with the thermostat 49 and float switch 49'. When the temperature of the water in heater tank 26 reaches a predetermined temperature thermostat 49 closes and the timer motor is energized. Thereafter the cam 67' will operate to close switch 67 and thus energize the pump motor 16. in the heater tank 26 to close the float switch 43 the heater 42 (and lamp) will not be energized. After the timer motor starts operating the first rise 64 of the cam disc lifts valve 57 of inlet valve 22, permitting water to flow to pump 14 and thence through conduit or hose 33 to rotary arm 36. It will be noted that hose 33 is relatively long and the hose 18 formed of relatively soft rubber whereby the hose may readily expand and contract to dampen or smooth out liquid pulsations emanating from the pump before the pulsations reach vat 10. Water discharged into the vat from jet nozzles 37 is returned to the pump for recircuthrou h conduit 21, against the head of water in conduit .son skilled in the art.

13. uring the commencement of the washing period the inlet valve 22 is openedbut is closed for the remainder of the washing period, the drain valve 27 being opened at the end of the washing period, whereby the pum discharges wash water through drain hole 28 to a sin or the like.

In a dishwasher having a recirculating liquid system ,as described, it is desirable to usean impeller type pump and preferably having impeller blades formed of rubber or the like to be sutficiently flexible to pass food particles and the like removed from articles being washed without danger of clogg ng the pump. This results in a pulsating act on as water is picked up at the axial inlet of the pump, whirled towards the periphery of the pump casing, and is discharged to hose 33 through the tangential outlet for the pump. Shnce water is relatively incompressible, this would result in successive impacts or vibrations which would be directly transmitted to the machine if the motor.

were rigidl y mounted or if a conduit of short length or relatively rigid material leading to vat 10 were used, since, to some degree, the vat acts as a sounding board. This would result in highly objectionable noise. I have found that by providing a resilient or limited floating mounting for the motor-pump unit, plus providing a relatively long conduit formed of relatively soft rubber and extending from the pump outlet to the vat, the noise is very substantially reduced. In effect, the soft rubber hose expands and contracts tending to smooth out or dampen the pulsations before they reach the vat. These pulsations will occur to a greater or less degree regardless of the type pump used.

I have described the invention in connection with a dishwashing machine having a built-in storage tank adapted to be gravity filled, but it is understood that the invention is equally adaptable to a machine having a tank permanently connected to a water supply line or a machine not equ pped with a built-in tank, but requiring a water circulating system of the general type described. In other words, the wash and rinse water could be directly introduced nto vat 10.

I wish it to be understood that I do not desire to be limited to the exact details of construction shown and described for obvious modifications will occur to a per- What I claim is: i

1. In a dishwashing machine, the combination of a vat, a; motor-pump unit mounted beneath the vat, and a liquid circulating system for delivering water to the vat under pressure and returning liquid from the vat to the pump, said circulating system comprising a built-in heater tank adapted to receive liquid for washing and rinsing operations, an nlet valve, a drain valve, timer means for operating said valves in sequence, conduit means extending from the tank to the inlet valve, a continuously open co iduit extending from the vat to the pump, com municating means between the inlet valve and pump, and communicating means-between the drain valve and pump whereby when the inlet valve is opened for a predetermined period liquid from the tank will be delivered to the liquid circulating system for recirculation through the yet by the pump and when the drain valve is open liquid from the vat will be discharged.

2. The combination as described in claim 1, and wherev in the heater tank is adapted to be gravity filled, an electrically energizable heater is disposed in the tank, a float switch prevents energization of said heater until a predetermined level of liquid is attained in the tank, and a thermostatic switch controlling the timer motor is mainta ned open until a predetermined temperature is attamed in the tank.

References Cited in the file of this patent UNITED STATES PATENTS

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