Power Supply Control Circuit For 120 Volt Combination Washer And Dryer

Abstract

This invention relates to a control circuit for a combination clothes washer and dryer adapted to operate on a 120 volt, 15 ampere, electrical supply. The control circuit includes a heat lockout relay energizeable to disconnect the dryer heater and dryer timer motor when the washer motor is in operation, thereby to limit the electrical current required by washer and/or dryer to the 15 ampere supply available. The circuit permits clothes tumbling to continue with unheated room air during washer motor operation.

Description

This invention relates to a laundry center combination including a clothes washer and clothes dryer designed for operation on a 120 volt, 15 ampere electrical circuit.

Prior art laundry centers of the type described in U.S. Pat. No. 3,545,235 issued Dec. 8, 1970, are designed to be connected to a 230 volt domestic power supply. This requirement for high voltage prevents the appliance from being used on the more common low voltage 120 volt domestic power supply. Accordingly, this invention is directed to a circuit arrangement which facilitates the power sharing of the clothes washer and clothes dryer in a manner which facilitates the adaptability of the appliance for use with a 120 volt domestic power supply.

It is an object of this invention to provide a laundry center having combined clothes washer and clothes dryer designed for operation on a 120 volt, 15 ampere electrical circuit without exceeding the fused limits of the circuit.

A more specific object of this invention is the provision of a control circuit for a combined domestic clothes washer and dryer which disconnects the dryer heater and dryer timer while continuing the operation of the dryer motor when the clothes washer motor is in operation.

A still further object of this invention is the provision of a heat lockout relay in the aforementioned circuit which includes a relay coil in parallel with the clothes washer motor and a relay switch in series with the clothes dryer timer motor and the clothes dryer heater.

Further objects and advantages of the present invention will be apparent from the following description, reference being had to the accompanying drawings, wherein preferred embodiments of the present invention are clearly shown.

IN THE DRAWINGS

FIG. 1 is a perspective view of the combination washer-dryer with parts cut away to show major components of the control circuit of this invention;

FIG. 2 is a schematic representation of the control circuit of this invention;

FIG. 3 is a timer cycle chart illustrating the clothes washer timer operation in the circuit of FIG. 2; and

FIG. 4 is a timer cycle chart illustrating clothes dryer timer operation in the control circuit of FIG. 2.

In accordance with this invention and with reference to FIG. 1, a laundry center 10 is illustrated showing structure adapted by the teachings of this invention to operate on a 120 volt, 15 ampere, domestic electrical power supply circuit.

The laundry center is comprised of clothes washer portion 12 and a clothes dryer portion 14 joined together along a common plane or jointure 16 in a manner described more fully in U.S. Pat. No. 3,611,756 issued Oct. 12, 1971. The washer may be loaded through an access lid 15 and the dryer through a dryer door 19.

Clothes washer 12 includes a plastic tub assembly 20 and agitator 21 of the type taught in U.S. Pat. No. 3,603,118, issued Sept. 7, 1971. Tub assembly 20 is selectively driven in either an oscillating mode for agitating clothes during washing or a spinning mode to centrifuge water from clothes after washing. An oscillating and spinning mechanism 24 of the type taught in U.S. Pat. No. 3,584,482, issued June 15, 1971, is provided for selectively driving the tub assembly 20. Mechanism 24 includes a two-speed, 4 pole, 6 pole induction washer motor 30 as the prime mover for the mechanism. The operation or energization of motor 30 is under the control of a washer timer 34.

Clothes dryer 14 is provided with a split drum construction of the type taught more fully in U.S. Pat. No. 3,584,393, issued June 15, 1971. The construction includes a tumbling drum 40 rotatably supported on rollers 42 and rotated by a dryer motor 44 by means of a belt 46 which interconnects motor 44 and tumbling drum 40. Means are provided for passing a stream of air through tumbling drum 40. For this purpose, clothes dryer 14 includes a perforated rear wall 50 to facilitate the inlet of ambient air to the tumbling drum. A perforated panel 52 at the front of the tumbling drum provides the outlet for the air stream from the tumbling drum. A blower 56, also operated by dryer motor 44, induces the flow of air through the tumbling drum from the perforated inlet panel 50 through the perforated outlet panel 52. This stream of ambient air will, in time, dry clothes tumbling therein. To expedite drying, a heater 60 is located behind perforated panel 50 and in heat transfer relationship to the air stream being drawn into the tumbling drum by blower 56. The operation of dryer motor 44 and dryer heater 60 is under the control of a dryer timer 64.

The control circuit of this invention will be described with reference to FIG. 2 wherein washer timer 34 and dryer timer 64 are shown in dotted line.

In accordance with conventional practice, the control circuit portion for the clothes washer will include a cold water fill valve solenoid 70, a hot water fill valve solenoid 72, and a water level switch 74 for terminating fill when a predetermined water level is reached in tub assembly 20. A water temperature selector switch 76 may be provided for selecting various combinations of water temperature for washing and rinsing in accordance with the following selector switch positions:

WATER TEMPERATURE SELECTOR

Switch Position

1. Hot wash -- Warm Rinse

2. Cold Wash -- Cold Rinse

3. Warm Wash -- Cold Rinse

4. Hot Wash -- Cold Rinse

Selector switch position numbers at each switch indicate switch positions which cause switch to operate opposite to the position shown.

A lid switch 80 is provided to disconnect the clothes washer from a domestic 120 volt, 15 ampere domestic power supply L1, L2, whenever clothes washer lid 15 is raised.

Clothes washer timer 34 includes a push-pull main line switch 82 and a plurality of timer switches 84, 86, 88, 90, 92, and 94 operated selectively by washer timer motor 96 into engagement with the circled contact numbers in accordance with the washer timer cycle chart of FIG. 3.

Also in accordance with conventional practice, the dryer circuit portion may include a high limit switch 100 to guard against excessive dryer temperatures and a control thermostat 102 for predetermining temperatures for the stream of drying air in accordance with the position of a fabric selector switch 104. The dryer may be started by start switch 110 whenever door switch 112 is closed along with dryer door 19.

Dryer timer 64 is comprised of dryer timer switches 116 and 118 selectively operated by dryer timer motor 120 in accordance with the dryer timer cycle chart of FIG. 4.

In accordance with this invention, a heat lockout relay 130 is provided to prevent the operation of dryer heater 60 and the advance of the dryer timer cycle whenever clothes washer motor 30 is conditioned for operation. The heat lockout relay 130 includes a switch 132 in series with dryer timer motor 120 in timer motor circuit 122 and in series with heater 60 in heater circuit 124. Timer motor circuit 122 and heater circuit 124 are in parallel with each other and relay switch 132 is interposed between the domestic power supply line L2 and the parallel circuits including the timer motor and heater. A dryer motor speed switch 125 may also be included in circuit 124 to condition heater 60 for operation only when dryer motor 44 is operating.

Switch 132 in heat lockout relay 130 is operated by a relay coil or switch actuating means 134 rated at 1750 ohms. The relay coil 134 is adapted when energized to open relay switch 132 and is in a relay circuit 136 in parallel with clothes washer motor 30 and in series with timer switch 88. Thus, whenever motor contact 5 is closed by timer switch 88 to energize washer drive motor 30, relay coil 134 will also be energized to open relay switch 132 and deenergize dryer timer motor 120 and circuit 124 for dryer heater 60.

With dryer 14 in operation (motor 44 and heater 60 energized), the current draw is approximately 14.7 amperes (3.0 amperes by the motor 44 and 11.7 amperes by heater 60). If washer motor 30 is energized without the control circuit of this invention, the current draw would exceed the allowable current limitations for the 15 ampere domestic power supply L1, L2. By this invention the current is limited by placing the single pole, single throw, normally closed relay switch 132 in the circuit 124 for dryer heater 60. When washer motor 30 is energized, relay coil 134 is energized to open relay switch at 132 and deenergize the dryer heater circuit 124. The current draw of the entire laundry center is therefore limited to the dryer portion in operation (heater 60 and dryer motor 44 energized), the washer portion in operation (washer motor 30 energized), or the washer portion and only dryer motor 44 from the dryer portion.

The dryer timer motor 120 is in a parallel circuit 122 with the heater circuit 124 for dryer heater 60 so that the advance of timer 64 will be deferred when dryer heater 60 is deenergized by means of the heat lockout relay switch 132. In this way, the necessary heater ON time is preserved in any given drying cycle even if the washer and dryer are in simultaneous operation. Whenever washer timer 34 completes its cycle or de-energizes washer motor 30 by opening timer contact 5, relay coil 134 will be deenergized to close relay switch 132 and recondition circuits 122 and 124 for operation respectively of dryer timer motor 120 and dryer heater 60. With the restart of the dryer timer cycle, clothes drying will be completed in a heated stream of air through the tumbling drum.

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

Claims

What is claimed is:

1. In a combination clothes washer and dryer wherein said washer includes a tub adapted to contain clothes to be washed, an agitator adapted for agitating clothes in said tub for washing said clothes, a washer motor for driving said agitator and a washer timer including a washer motor switch connected to one side of said washer motor for selectively operating said washer motor and wherein said dryer includes a tumbling drum adapted to contain clothes after said washing, a blower for blowing a stream of air through said tumbling drum, a dryer motor for driving said tumbling drum and blower to tumble said clothes in said air stream, a heater in heat exchange relation with the air stream for drying said clothes in a stream of heated air, and a dryer timer including a dryer motor switch connected to one side of said dryer motor for selectively operating said dryer motor and a heater switch connected to one side of said heater for selectively operating said heater and a dryer timer motor for opening and closing said dryer timer switches through a predetermined time cycle, the invention comprising a power supply control circuit adapted to energize said combination washer and dryer from a 15 ampere domestic power supply without exceeding the fused limits thereof, said circuit including first power supply means connecting one side of said power supply to the timer switches for said washer motor, dryer motor and heater, said washer motor switch being in parallel with said dryer motor switch and said heater switch, said dryer timer motor being connected to said first power supply means through said dryer motor timer switch, and second power supply means connecting the other side of said power supply to the other side of said washer motor, dryer motor, dryer timer motor and heater, said second power supply means including a relay switch in series with said dryer timer motor and said heater, and actuating means in series with said washer motor switch for opening said relay switch whenever said washer motor switch is closed, whereby to prevent the operation of said heater and said dryer timer motor whenever said washer motor is conditioned for operation, said dryer motor remaining in condition for operation through said dryer motor switch irrespective of said relay switch whereby to tumble said clothes in a stream of unheated air whenever said washer motor is conditioned for operation.