US2807889A - Control system for clothes dryers - Google Patents

Description

Oct. 1, 1957 R. L. DUNKELMAN CONTROL SYSTEM FOR CLOTHES DRYERS 2 Sheets-Sheet 1 Filed March 8, 1956 HIGH H AT CON ROLLED m K m R P s ETA RT HEAT HIS ATTORNEY Oct. 1, 1957 R. L. DUNKELMAN CONTROL SYSTEM FOR CLOTHES DRYERS 2 Sheets-Sheet 2 Filed March 8, 1956 N WF m@ ON I. j

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ROBERT L. DUNKELMAN HIS ATTORNEY United States Patent CONTROL SYSTEM FOR CLOTHES DRYERS Robert L. Dunkelman, Shreveport, La.,

assignor to General Electric Company,

My invention relates to clothes dryers and more particularly to the electrical control systems used in such dryers.

It is an object of my invention to provide a new and improved control system for clothes dryers.

It is another object of my invention to provide a control system for clothes dryers, whereby a dryer may be selectively operated to produce a plurality of different clothes treating operations including a high heat clothes drying operation wherein the heater of the dryer is energized continuously, and a controlled heat clothes drying operation where in the heater is cycled by a thermostat.

A further object of my invention is to provide a clothes dryer control system, whereby a dryer may be selectively operated to produce three different clothes treating operations comprising respectively a controlled heat clothes drying operation, a high heat clothes drying operation, and a clothes tumbling operation without heat.

Another object of my invention is to provide a clothes dryer control circuit of this latter type including thermostatic means for automatically terminating either of the clothes drying operations when the clothes have substantially dried.

Still another object of my invention is to provide a clothes dryer control system effective to produce the three operations, in which the drive motor and heater circuits are closed through the contacts of a relay which is dropped out automatically by thermostatic means in the two drying operations when the clothes have completed drying.

A still further object of my invention is to provide a clothes dryer control circuit in which the drive motor and heater circuits are closed through the contacts of a thermostatically closed relay and in which the opening of the dryer door interrupts the two circuits but does not cause dropping out of the relay, whereby both circuits are again rendered operative when the door is reclosed.

My invention also has as its object the provision of a clothes dryer control system including a relay having contacts in the drive motor and heater circuits, which is energized by means of a remotely located push button to initiate the dryer operation and which is de-ener gized by thermostatic means to terminate dryer operation when the clothes have dried.

In carrying out my invention I provide a clothes dryer having suitable clothes tumbling means. A drive motor is provided for driving the clothes tumbling means and a heater is arranged for heating the clothes being tumbled. By my invention the drive motor and the heater are controlled by means of a novel control system which includes a timer mechanism and a heater cycling thermostat. This control system provides for three different operations of the dryer comprising respectively a high heat clothes drying operation wherein the heater is energized continuously, a controlled heat clothes drying operation wherein the heater is cycled by a thermostat, and a clothes tumbling operation without heat wherein the heater is de-energized at all times.

in the system the drive motor and the heater are both energized by circuits through switches of the timer mechanism. In addition to its timer switch, the heater circuit also includes the cycling thermostat and a normally closed manually operated heater switch. Further, the heater circuit includes a normally open manually operated shunt switch connected in parallel with the contacts of the thermostat. The drive motor is energized in all three opera; tions of the dryer, and the different operations are effected by means of the manually operated switches in the heater circuit. To produce the controlled heat clothes drying operation both switches are left in their normal positions whereby the heater is cycled by the thermostat during the drying operation. Alternatively, to provide the high heat operation, the shunt switch around the thermostat is closed and thereby the heater is energized continuously. The clothes tumbling operation without heat is effected by opening the heater switch whereby the heater is completely de-energized. The manually operated switches are preferably controlled by push buttons whereby move ment of either of the switches from its normal position returns the other of the switches to its normal position.

In my preferred system there is also included a relay having contacts in both the drive motor circuit and the heater circuit, and a second thermostat responsive to the exhaust air leaving the tumbling means for controlling the relay. To initiate the dryer operation a push button is operated which is effective to energize the relay coil and .thereby close both circuits. The exhaust air thermostat is effective to de-energize the relay coil when the clothes have dried, and thereby terminate the dryer operation no matter what the position of the timer mechanism. For safety purposes this preferred control system also includes means whereby both the motor circuit and the heater circuit are de-energized whenever the dryer door is opened, but the relay coil is so arranged that it remains energized even when the door is opened. Thereby the motor and heater circuits are both returned to operation auto matically when the door is reclosed.

The features of my invention which I believe to be novel are set forth with particularity in the appended claims. The invention itself, however, both as to its organization and method of operation may be best understood by reference to the following description taken in conjunction with the accompanying drawings in which:

Fig. 1 is a perspective view of a domestic clothes dryer including a control system embodying my invention, the view being partially broken away in order to show details;

Fig. 2 is a fragmentary view showing the operator controls of the control system; and

Fig. 3 is a schematic diagram of the control system itself.

Referring now to Fig. 1 I have shown therein a clothes dryer 1 which is illustrative of the various clothes dryers in which my new and improved control system may be used. The dryer 1 includes a rotatable drum or basket 2 which is mounted for rotation about a generally horizontal axis. The basket 2 is disposed within an outer enclosing cabinet structure 3 and aligned openings 4 and 5 are provided respectively in the front walls of the basket and the cabinet structure for the loading and unloading of clothes from the basket. The openings 4 and 5 are flanged as shown to prevent clothes from dropping down between the basket and the cabinet. A door 6 hingedly mounted on the cabinet closes the opening 5 during operation of the dryer.

For rotating the basket 2 during operation of the dryer there is provided an electric motor 7 which is connected to the basket by a suitable belt drive 8. The pulleys (not shown) mounting the belt drive are so arranged that the basket 2 'is driven at a suitable speed for tumbling articles of clothing placed therein. The basket '2 preferably includes upstanding ribs on the inner surface thereof to aid in producing the tumbling action. Besides driving the basket 2, the motor 7 also serves to drive air moving means for circulating a stream of air through the basket during the operation of the machine. The air moving means comprises a centrifugal blower 9 which is driven by motor 7 by means of a direct coupling 10. The blower 9 draws in air from the surrounding room through a conduit 11 which leads from a screened air inlet opening 12 in the toe board 13 of the cabinet.

The air drawn in by the blower 9 is discharged through an opening 14 at the top thereof into a space 15 which is separated from the rotating basket 2 by a battle 16. As shown, the baffle 16 extends upwardly from the base of the machine to a point in the general vicinity of an electrical heating element 17 mounted at the top of the machine, the bafiie 16 being curved arcuately around the perforated side wall 18 of the basket for a portion of its length. The air discharged from the blower 9 flows upwardly through the space 15 and passes outwardly there from across the electrical heating element 17. The air still under pressure from the blower then flows downwardly through the formaminated cylindrical wall 18 of the basket. A generally arcuate bafile or wrap-around 19 confines the flow path of the air so that it is positively passed through the wall 18 into the basket. The air moves downwardly through the basket and the articles of clothing being tumbled therein and next passes into a collecting chamber 20 lying beneath the basket 2 on the opposite side of the baflie 16 from the space 15. From the chamber 20 the air is discharged out of the cabinet into the surrounding room through an appropriate lint trap structure 21 mounted in the toe board 13.

The machine 1 is intended for use both as a clothes drying means and as a clothes sprinkling means. When the machine is to be used as a clothes dryer the heater 17 is energized along with the drive motor 7. Thus the air discharged from space 15 absorbs heat from the heater 17 as it passes thereover. The heated air then extracts moisture from the clothes being tumbled in the drum as it passes therethrough. The heating element, however, is not energized when the machine is being used as a clothes sprinkling means. Thus the air passing through the drum is not heated and it does not extract moisture from the clothes. Any suitable means may be used to sprinkle the clothes during this operation, but it is preferred to use a container which can be mounted on the drum 2 so as to discharge water onto the clothes at a slow rate as the basket rotates. A suitable container for this purpose is shown and described in the copending application of Eugene G. Olthuis, S. N. 430,794, filed May 19, 1954, and assigned to the same assignee as the present invention. It will be understood, of course, that if the sprinkling means are not mounted within the drum, this clothes tumbling operation of the dryer without heat may be used for flufling previously dried clothes or for any other purpose wherein it is desired to tumble clothes without the application of heat.

Referring now to Fig. 3 I have shown therein a control system for the dryer 1, which embodies my invention in one preferred form thereof. This control system provides forthree different types of clothes treating operations to be carried out within the dryer. It provides for a high heat clothes drying operation wherein the heater 17 is energized continuously so long as the drying operation continues. It also provides for a controlled heat operation wherein the heating element 17 is cycled on and off by a cycling thermostat so that the temperature of the inlet air entering the drum 2 never rises above a predetermined temperature. Further, it provides for a clothes tumbling operation without heat wherein the heater 17 is not energized at any time. 1 In order to time the length of the clothes tumbling or sprinkling operation and also in order to provide timed clothes drying operations of both of the above mentioned types, i. e., the high heat type and the controlled heat type, the control system includes a timer mechanism 22. The timer mechanism comprises a timer motor 23 and a pair of cams 24 and 25 which are driven by the timer motor through suitable one-way clutch means. The cams 24 and 25 operate switches 26 and 27 respectively through suitable cam followers which ride on their peripheries. The two switches 26 and 27 are connected respectively in the circuits for energizing the drive motor 7 and the heater 17, the switch 26 being connected serially in the heater circuit and the switch 27 being connected serially in the drive motor circuit. Both the drive motor and the heater circuits and the connection of the switches 26 and 27 in these circuits will be more fully described hereinafter. in order that the switch operating earns 24 and 25 may be adjusted to any desired position, the timer mechanism is provided with a rotatable dial 28 which is mounted on the same shaft as the cams. By adjusting the dial 23 and thus the earns 24 and 25, the timer may be set to operate for various periods of time before opening switches 26 and 2'7 and breaking the heater and drive motor circuits. The timer mechanism may be mounted at any suitable point within the machine but preferably is mounted on the back: splasher 29 thereof as is shown in Fig. 1.

Besides the timer mechanism 22 the control system also includes thermostatic means for determining the length of the machine operation. These thermostatic means are operative during both the high heat clothes drying operation and the controlled heat clothes drying operation to terminate the operation of the machine whenever the clothes have dried. No matter what the original setting of the timer may be, these thermostatic means will shut off the dryer as soon as the clothes have completely dried. Thus no matter how mistaken the operator may be in her setting of the dial 28, it is impossible for the clothes to be scorched or otherwise heat damaged.

The thermostatic means for terminating the clothes drying operations comprise two thermostats 30 and 31 which are responsive to the temperature of the exhaust air leaving the rotating drum 2. These thermostats may be positioned within the exhaust air collecting chamber 20 in any suitable manner so as to sense the exhaust air temperature. For example, a bracket 30a for mounting the thermostat 30 is shown in Fig. 1. The exhaust air temperature closely follows the temperature of the clothes being tumbled and thereby the thermostats 30 and 31 in etfect respond to the clothing temperature.

During the clothes drying operation, the temperature of the clothes and thus the exhaust air temperature rise slowly as the drying operation progresses. For a period of the operation a plateau may even occur in this temperature rise where the amount of heat utilized in moisture extraction is approximately equal to that supplied from the heater 17. However, when the clothes have substantially dried, the clothing temperature and the exhaust air temperature then begin to rise abruptly. The purpose of the thermostat 30 is to open the heater circuit and thereby de-energize the heater 17 when the clothes have substantially dried. The thermostat 30 is thus arranged so that it remains normally closed during the slow rise in the exhaust air temperature accompanying the drying process. In other words it is set so that it does not open at the temperatures through which the slow rise occurs. It is set however to open at a temperature slightly above that at which the abrupt rise does occur. In this manner the thermostat 30 remains closed so long as the drying process continues but opens as soon as the clothes have dried. The means whereby the thermostat 30 opens the heater circuit once it opens itself are described hereinafter.

The other exhaust air thermostat 31 is utilized to provide a cool-down period for the machine after the heater 17 has been turned off by the thermostat 30. In other words the thermostat 31 maintains the drive motor 7 running after the heater has been turned off to continue in operation the tumbling drum and the blower 9. This continued operation of the tumbling drum and the blower results in the clothes being tumbled with air at room temperature being blown through them. The clothes are thus cooled down to a suitable temperature for removing them from the machine. When this temperature is reached the thermostat 31 opens the motor circuit and terminates the operation of the dryer completely. The circuit whereby the thermostat 31 accomplishes this result is explained hereinafter. To eifect this result the thermostat 31 is calibrated so that it is normally open at room temperature, but is closed at any temperatures above those suitable for removing the clothes from the drum. Thus during the dryer operation the thermostat 31 is open when the dryer is first placed in operation. However it closes as the machine heats up during the drying operation and does not again re-open until the point in the cool-down period is reached where the temperature is suitable for the removal of the clothes.

In order to provide means whereby the heater circuit may be opened before the motor circuit, the control system is provided with a relay 32. This relay includes a coil 33 and an armature 34 which is operated by the coil. It further includes three sets of contacts or switches 35, 36, and 37 which are operated by means of the armature. All of these sets of contacts or switches are closed whenever the armature is raised by the coil 33, and all are opened whenever the coil is de-energized to allow the armature to drop out. It will be noted incidentally that the switches 36 and 37 share a common contact or switch arm. The switch 35 is connected serially in the energizing circuit for the heater 17 and the switches 36 and 37 are connected in series in the energizing circuit for the drive motor 7. Thus whenever these switches are opened, both the heater and the drive motor circuits are broken at those points.

During the operation of the machine the coil 33 of the relay is normally energized by means of the thermostat 30. Thus the switches 35, 36 and 37 are held closed until the clothes have substantially dried. At that point, however, the thermostat opens and tie-energizes the coil 33 allowing the relay to drop out. This de-energizes the heater circuit by means of the switch and also of course opens the drive motor circuit. However the overrun thermostat 31 provides a parallel path around the switches 36 and 37 to keep the drive motor energized during the cool-down period. Both the heater circuit, the drive motor circuit and the circuit for energizing the relay coil 33 are described hereinafter.

In order to produce selectively the two types of clothes drying operations and the clothes tumbling operation without heat, two manually operated switches 38 and 39 and a heater cycling thermostat 40 are provided in the heater circuit. The switch 38 is a normally closed switch, and it and the thermostat 40 are connected in series circuit relation in the heater circuit with the heater itself. The switch 39 however is a normally open switch and rather than being connected in series circuit relation it is connected in parallel with the contacts of the thermostat 40. In other words it forms a normally open shunt around the thermostat 40.

The purpose of the switch 38 is to de-energize the heater 17 during the operation of the dryer, thereby to produce the clothes tumbling or sprinkling operation without heat. Conversely, the purpose of the switch 39 is to maintain the heater energized continuously during the operation of the machine to obtain the high heat drying operation. The thermostat 40 is included for controlling the heater to produce the controlled heat clothes drying operation of the machine. Specifically, when the thermostat 40 is placed in operation, it is intended to control the heater 17 so as to maintain the inlet air to the drum at a temperature safe for all types of fabrics. It does this by cycling the. heater on and 01? in response to the inlet air temperature. The thermostat 40 may be positioned at any suitable place to sense the inlet air temperature but 6 preferably is mounted near the top of the battle 19 as shown.

The three different types of clothes treating operations are produced as follows. If it is desired to effect a clothes tumbling or sprinkling operation without heat, the switch 32% is opened. This breaks the motor circuit and prevents the heater from being energized at any time. If it is desired to produce the controlled heat operation, the switch 38 is closed and the switch 39 is left open. This places the heater under the control of the cycling thermostat as whereby the heater is cycled on and 01f to keep the inlet air to the drum at a temperature safe for the sheerest fabrics and synthetics. If it is desired to have the high heat operation of the dryer, then both the switches 38 and 39 are closed. The closing of the switch 39 shorts out the thermostat whereby the heater is energized continuously until either the exhaust thermostat 30 opens or the timer mechanism times the machine out.

In my preferred embodiment the heater control switch 38 and the thermostat shunt switch 39 are operated by means of a plurality of push buttons 41, 42 and 43. The push buttons are all mounted within a housing 44, which housing also serves to mount the switches 38 and 39. Each of the push buttons is provided with an inwardly extending switch actuating arm 45, 45a and 4511 respectively, and each of these operating rods is provided with two laterally extending tabs thereon. One of the tabs is provided adjacent the center of the rod as indicated at 46, 46a and 46b respectively, and the other of the tabs is formed at the end of the red as shown at 47, 47a and 47b respectively. The tabs 47 and 47a on the rods 45 and 45a of buttons 41 and 42 engage respectively one of the arms of the switches 38 and 39. Specifically, if the button 41 is pushed inwardly tab 47 engages the right-hand arm of the switch 38 so as to open switch 38. Conversely if the button 42 is pushed inwardly, tab 47a engages the left hand arm of the switch 39 so as to close switch 39. The push button 43 does not operate a switch when pushed inwardly, but rather is used to return both the buttons 41 and 42 to their normal or outward position.

The push buttons 41, 42 and 43 are so arranged that whenever any of them is pushed inwardly, the other two are automatically returned to their outward positions. This automatic return action is effected by means of the center tabs 46, 46a and 46b on the operating rods 45, 45a and 455. These tabs engage respectively upstanding lugs 48, 48a and 48b provided on a movable latch rod 49 whenever they are moved inwardly. The opposite ends of the latch rod 49 are mounted in aligned apertures 50 in the side walls of the casing 44 so that the rod is axially movable within the casing, and the rod is spring biased to the right (as viewed in Fig. 3) by means of a spring 51. As shown, each of the lugs on the latch rod includes an inclined surface, as indicated at 52, 52a and 52b, and further includes a recess disposed below the lower point of the inclined surface as indicated at 53, 53a, and 53b. As any of the push buttons are moved inwardly the center tab 46, 46a or 4612 thereof strikes the inclined surface of its associated lug 48, 48a or 43!) and moves the latch rod 49 to the left. This movement of the latch rod to the left releases the center tab of whatever push button was previously depressed and that push button is thereby returned to its normal or outward position by the action of a return spring which is disposed between it and a cross piece mounted on the housing. The return springs are shown at 54, 54a and 54b respectively. Once the center tab on the button being pushed passes the point of the inclined portion of the lug, however, the latch rod springs back to the right and the appropriate recess 53, 53a or 53b engages the tab to maintain that push button down.

To explain this action a little more fully, in the position of the control illustrated the. push button 43 is depressed downwardly and held in that position by the engagement of the latch rod lug 48b with the tab 46b. Now assume that the button 41 is pushed inwardly. As a result of the movement of the button 41, the latch rod will be moved to the left by the tab 46 thereby freeing the tab 46b. The button 43 will, therefore, move outwardly under the action of the spring 54b and return to its normal position. However, as soon as the tab 46 of the button 41 passes the right hand point of the inclined surface 52 on lug 48, the latch rod will spring back and hold the button 41 inwardly. The tab 4-6 will be caught in recess 53 whereby the button can not move outwardly. The same result will be effected no matter which of the button is pushed inwardly. The button pushed inwardly will be held in the depressed position while all the other buttons will be released and automatically returned to their outward or normal positions.

Besides the push buttons 41, 42 and 43 the control also includes one additional push button 55. This push button 55 is mounted on the backsplasher 29 adjacent the other push buttons and comprises a start button for initiating the operation of the machine. It controls a switch 56 which is connected in the holding circuit for relay coil 33 as explained below.

To explain in detail the operation of my new and improved control system and also the various electrical connections contained therein, let it be assumed that it is desired to effect a controlled heat clothes drying operation within the dryer ll. Further, let it be assumed that it is desired to have the dryer turned off automatically when the clothes are dried, rather than to have the dryer set to run for a predetermined length of time. To condition the dryer for this operation the push button 43 is depressed and the dial 28 is moved into the section marked dry on the dial. The depressing of button 43 causes switches 38 and 39 to assume their normal positions for energizing the heater through the thermostat 40, and the setting of the dial 28 conditions the timer mechanism for placing the machine in operation. Specifically, the setting of the timer rotates the leading edges of the raised portions of the cams under the cam followers of switches 26 and 27. This closes the switches 26 and 27, and since the dry portion of the dial 28 is immediately adjacent the off sector, the timer is set to run for the maximum possible time before it will open the switches 4 26 and 27.

With the dial set in the dry position and the push button 43 depressed, the operation of the machine is initiated by depressing the start button 55. This closes the start switch 56 and closes a circuit for energizing the coil 33 of the relay 32. All the electrical components of the dryer and the control system are energized from a three-wire power source comprising supply conductors 57 and 58 and a neutral line 59, and the closing of the start button energizes the coil 33 between the neutral line and the conductor 58. In my preferred circuit for domestic use it is contemplated that there will be a voltage of 220 volts between the supply conductors 57 and 58 and a voltage of 110 volts between the neutral conductor 59 and each of the supply conductors, and thus when the switch 56 is closed, the relay coil 33 is energized across 110 volts.

Starting with the neutral conductor 59 the relay coil circuit closed by the start switch extends through a fusible link 60 and a conductor 61 to the closed switch 27 of the timer mechanism. From the switch 27 the circuit proceeds through a conductor 62, the start switch 56 itself and conductors 64 and 65 to one side of the relay coil 33. The circuit is completed from the relay coil through conductors 66, 67 and 63 to the supply conductor 58. With the relay coil 33 energized by this circuit through the start switch, the armature 34 is lifted upwardly closing the switches 35, 36, and 37 with the switches 36 and 37 being connected together through their common contact.

One result of the closing of the various switches of the relay is that the relay coil itself is locked in so that the start button 56 may be released. Specifically, the relay coil is locked in by a circuit through the switch 36 and the exhaust thermostat 36. Starting with the conductor 62 which is, of course, connected to the neutral line 59 by the timer switch 27, the holding circuit for the relay extends through a conductor 69, the switch 36, a conductor 70, the closed thermostat and a conductor 71 to the conductor connected to the one side of the relay coil. The relay circuit is completed from the other side of the coil as before through the conductors 66, 67 and 68 to the supply conductor 58. With this circuit completed by the closing of the switch 36, it will be seen that the relay is locked in until such time as the. exhaust thermostat 30 is opened by the temperature of the exhaust air. The thermostat 30 is, of course, not open until such time as the clothes are dried, it opening only at an exhaust air temperature which indicates that the clothes have reached that condition.

The closing of the relay 32 also results in circuits being completed for the heater l7 and the drive motor 7. Specifically, the drive motor is energized by a circuit across the neutral line 59 and the conductor 58. Commencing with the neutral line 5? the motor circuit ex-v tends through fusible link 60, conductor 61, timer operated switch 27, and conductors 62 and 69 to the switch 36. It then passes through the relay switches 36 and 37 in series and proceeds through. conductors 72 and 73 to a switch, 74 which is controlled by the door 6. The switch 74 is so arranged with regard to the door 6 that it connects the conductor 73 to one contact 75 when the door is closed, whereas when the door is open it connects the conductor 73 to a second or back contact 76. Assuming the door of the machine to be closed the motor circuit extends through the switch arm and the contact 75 to a conductor 77, and from the conductor 77 it passes through another conductor 78 to the start and run windings 79 and 88 of the motor 7. From the windings 7 9 and 80 the motor circuit is completed through the conductor 68 to the suppiy conductor 58. As shown, the run winding 80 is connected directly to the conductor 68. The start winding is, however, connected thereto through the contacts 81 of a motor centrifugal switch 82 and the conductors 83 and 67. The centrifugal switch 82 is operated by the motor 7, and it is so arranged that the contacts 81 are closed whenever the motor is at rest but are opened as soon as the motor comes up to speed. Thus the start winding 79 is connected in the circuit only until the motor comes up to speed. it is then removed from the circuit by the centrifugal switch and the motor continues to run under the action of the main winding 86 alone. With the motor energized through this circuit, it will be seen that it will continue to operate until such time as either the timer operated switch 27, the door switch 74 or the relay 32 is opened.

The heater circuit completed by the closing of the relay 33 is energized across the supply conductors 57 and 53 so that the heater 17 is energized by the full 220 volts available in the supply. Commencing with the supply conductor 57, the two resistors 34 and 85 of the heating element are directly connected to that conductor. From the other side of the resistors, the heater circuit extends through a line 86 to the switch 38. Since the push button 43 is operated inwardly to obtain the desired controlled heat operation, the push button 41 is in its outer or normal position whereby the switch 38 is closed. From the switch 38 the heater circuit then passes through a conductor 87 to the thermostat 40, and from the thermostat it extends through conductors 88 and 89 to the switch 26 of the sequence control. Since the heater shunting switch 39 is not closed but rather remains open when the button 43 is depressed, the thermostat is connected serially in the heater circuit and will break the circuit whenever it opens. From the switch 26 the heater circuit continues through a conductor 90 to the switch 35 of the relay and thence passes through a line 91 to a set of back contacts 92 of the motor centrifugal switch 82. These contacts 2 are open when the motor is at rest but are closed whenever the motor comes up to speed. Assuming contacts 92 to be closed, the heater circuit is then completed through the conductors 83, 67 and 68 to the supply conductor 58.

Energized through this circuit it will be seen that the heater 17 will remain energized under the control of the cycling thermostat 40 so long as the timer operated switch 26, the relay switch 35 and the centrifugal switch contacts 92 remain closed. The opening of any of these switches or contacts will, however, interrupt the heater circuit and de-energize the heater. Due to the action of the thermostat 40, the heater is energized intermittently so as to keep the temperature of the inlet air to the-drum below the temperature which might result in harm to sheer fabrics and synthetics. For example, it is contemplated in one embodiment of my invention that the inlet air temperature will not be allowed to rise above 170 F. as a result of the action of the cycling thermostat 40.

Besides the drive motor circuit, the heater circuit and the relay holding circuit, one additional circuit is energized by the closing of the relay 33; and that additional circuit is a circuit for energizing the timer motor 23. The timer motor 23 is specifically energized by a circuit across the neutral line 59 and the conductor 58. Starting with the neutral line 59 the timer motor circuit extends through neutral link 60, conductor 61, timer operated switch 27, conductors 62 and 69, relay switches 36 and 37 in series, and conductors 72 and 73 to the door switch 74. From there the timer motor circuit continues through conductors 77 and 93 to the timer motor itself and is completed from the timer motor through conductors 94 and 63 to the supply conductor 59.

Energized through this circuit it will be seen that the timer motor will continue in operation until such time as either the relay switches or the door switch is opened. Opening of either of these elements will interrupt or terminate the timer motor operation. So long as the timer motor is energized it drives the cams 24 and 25 toward the off position, that is, the illustrated position, wherein the recesses in the cams 24 and 25 move under their respective followers to open the switches 26 and 27.

With the components of the control system and the dryer energized in this manner, the dryer continues in op eration to extract moisture from the clothes until one of two things happens, either the timer mechanism opens the switches 26 and 27 or the thermostat 30 opens the relay holding circuit. The timer opens the switches 26 and 27 after a predetermined length of time and the thermostat 30 opens the relay holding circuit when the dryer exhaust temperature indicates that the clothes have dried. If the switches 26 and 27 are opened, all of the circuits of the control system are opened and operation of the machine is completely terminated. The opening of the switch 26 disconnects the heater circuit and the opening of the switch 27 opens the drive motor circuit, the relay holding circuit and the timer motor circuit. Ordinarily it may be desired to have a machine cool-down period just before the operation is terminated, and in that case the cams 24 and 25 may be so arranged that the switch 26 is opened slightly before the switch 27. This will allow the dryer to operate without the heater being energized for a brief period before the dryer is completely shut off, thereby to allow it to cool down to a suitable temperature for the removal of the clothes.

However, for the particular example here involved let it be assumed that the clothes are completely dried before the timer mechanism times the machine out. In such case the thermostat 30 will open. This breaks the relay holding circuit and allows the relay armature 34 to drop out. In other words it allows the relay to open all of switches 35, 36 and 37. The opening of the contacts 35 opens the heater circuit whereby the air passed to the drum is no longer heated. The opening of the switches 36 and 37 likewise opens a point in the drive motor and timer circuits but as a result of the above-mentioned thermostat 31, the opening of these switches does not actually break the drive motor and timer circuits. Rather these circuits are still energized through the thermostat 31. The thermostat 31 closed when the dryer exhaust temperature rose above the desirable temperature for removing clothes from the machine, and the closing of the thermostat 31 completes an alternate circuit for energizing the drive motor and the thermostat.

Starting with the neutral line 59, this alternate circuit extends through fusible link 60, conductor 61, timer operated switch 27 and conductors 62 and to the thermostat 31 itself. The other side of the thermostat is connected directly to the conductor 73 and from there the drive motor and timer motor circuits are completed to the neutral line 58 in the manner described above. The thermostat 31 thus provides a circuit in parallel with the switches 36, 37 of the relay for energizing the drive motor and the timer motor when those switches are opened after the clothes have dried. The thermostat 31 remains closed to keep the drive motor and timer motor in operation until such time as the exhaust temperature drops to a point at which the clothes may be advantageously removed from the drum without any discomfort to the operator. When the dryer temperature reaches that point the thermostat 31 opens and that of course breaks the drive motor and timer motor circuits. The operation of the machine is then completely terminated with all the elements thereof being de-energized.

If it were desired to have the dryer operate on high heat rather than on controlled heat, the only difference in the control setting would be that the push button 42 would be pushed inwardly rather than the button 43. The movement of the button 42 inwardly closes the switch 39 and thus provides a shunt around the cycling thermostat 40. Thus when the dryer goes into operation as a result of the depressing of the start button 55, the heater 17 is energized continuously rather than being cycled on and off. As a result the temperature of the inlet air entering the drum will rise above the temperature held during the controlled heat operation and the clothes will dry more quickly. This high heat operation is generally more advantageous for loads of heavy fabrics and articles such as shag rugs, dungarees, etc. The operation will be terminated in the same manner as the controlled heat operation either by the sequential. opening of the exhaust thermostats 30 and 31 when the clothes have completely dried or else by the timer mechanism timing the machine out and opening the switches 26 and 27.

If it is desired to tumble clothes without the application of heat for sprinkling or other purposes, then the push button 41 is operated before the start button :35 is depressed. In that case the switch 38 is opened whereby the eater circuit still remains open after the relay 32 closes. The same timer motor, drive motor and relay holding circuits are completed as before so that the drive motor and the timer motor run the same as in the clothes drying operations. The only dilierence is that no heat is supplied to the clothes due to the break in the heater circuit. Since there is no heat applied to the clothes the exhaust thermostat 30 will never open and therefore the sprinkling operation is always terminated by the opening of the switches 26 and 27 by the timer mechanism. The length of time that the clothes will be tumbled and/ or sprinkled depends upon the original setting of the dial 28. If it is desired to sprinkle the clothes as well as tumble them, a suitable sprinkling container is, of course, placed within the drum 2.

With regard to both the controlled heat and the high heat clothes drying operations, both of them may be used to dry clothes completely in the manner described above. However, in addition they may be also used to damp dry clothes. In order to damp dry clothes the dial 28 is set at some point between the dry sector and the otf sector. In other words it is set at a position within the portion of the dial which is numbered in Fig. 2. With the dial set in such a position the timer mechanism ordinarily times the machine out by opening switches 26 and 27 before the exhaust temperature rises far enough to open the thermostat 30. Thus the machine will be turned off before the clothes are fully dried or in other words when they are still only damp dried. By pushing button 43 during this damp dry operation the temperature of the inlet air will be controlled by the thermostat 40. However if the button 42 is depressed the heater 17 will be energized continuously.

Referring now to the door switch 74, this switch provides a safety feature during the operation of the machine. If the door 6 is opened at any time during the operation of the machine, the switch arm moves from the contact 75 to the contact 76. By this action both the drive motor and the timer motor circuits are broken. With the drive motor circuit broken, the drive motor stops rotating the tumbling drum and the blower. Also, since the stopping of the drive motor results in the opening of the contacts 92 of the centrifugal switch, the heater circuit is deenergized too. Thus the heater 17 also ceases operation until such time as when the door is reclosed. This stopping of the drum rotation and de-energizing of the heater provides for operator safety as well as allowing for the insertion and removal of articles from the drum. The de-energization of the timer motor concurrently with the drive motor and the heater when the door is opened prevents the opening of the door from shortening the total time that the dryer is in operation. This control of the timer motor results in the timer mechanism counting only the time the dryer is actually in operation with the drum rotating, and not the shut-down time while the door is open.

In my improved control circuit the opening of the door does not, however, break the relay holding circuit. Rather the relay holding circuit remains energized even with the door opened so that the relay remains closed. Thus when the door is reclosed, the dryer will resume operation. When the door is opened, the relay holding circuit is energized through the back contact 76 of the door switch. The relay specifically is energized through the following circuit between neutral line 59 and supply conductor 58. Commencing with the neutral line 59 the circuit extends through the fusible link 60 and a connector 96 to the back contact 76 of the door switch. From contact 76 it passes through the switch arm, and conductors 73 and 72 to switch 37 of the relay, and from there continues through conductor 70, thermostat 3t and conductors 71 and 65 to the relay coil itself. The circuit is completed from the relay coil through conductors 66, 6'7 and 68 to the supply conductor 58. If the thermostat 31 has closed before the door 6 is opened, the relay holding circuit is also energized through it. But even if the thermostat 31 is not closed, the relay holding circuit will be energized through the above-described circuit whenever the door is opened. Thus the relay cannot drop out and the dryer operation will be resumed when the door is closed.

Besides those components already mentioned, my new and improved control also includes a light 97 for illuminating the interior of the dryer and an OZOne lamp 9% for freshening the air within the dryer. The lamps 97 and 98 are so connected that they are energized whenever the door is opened and also whenever the machine is in operation. In both cases they are energized between the neutral line 59 and the conductor 58. When the door is open, they are energized as follows. Commencing with the neutral line 59 the circuit extends through fusible link 60, conductor 96, the back contact 76 of the door switch, the door switch itself and a conductor 99 to the lamps. The lamps 97 and 8 are connected in series and the circuit is completed from them through a conductor 100 to the supply conductor 58. When the machine is in operation and the door is closed, the lamps 97 and 98 are energized through an alternate circuit commencing with the neutral line 59 and extending through the fusible link 60, conductor 61, timer operated switch 27 and conductors 62 and 69 to relay switches 36 and 37. From the relay switches the circuit passes through conductors 72, 73 and 39 to the lamps themselves and thence is completed and $9 to the lamps themselves and thence is completed to supply conductor 58 through the conductor 100. Connectcd in these circuits the lamps are thus energized whenever the door is opened or whenever the machine is in operation. Incidentally it will also be noted that whenever the thermostat 31 is closed, they are also energized through an alternate circuit through it. Thus they remain lit during the cool-down period of the machine following the drop-out of the relay 32.

From the above, it will be seen that l have provided a new and improved control system for a dryer which is effective to produce three different operations of the dryer. It provides a controlled heat clothes drying operation wherein the inlet air to the clothes tumbling drum is always kept at a safe temperature for even the sheerest of fabrics. It also provides for a high heat operation wherein the dryer heater is energized continuously. Further it provides a clothes tumbling or sprinkling operation wherein the tumbling drum is rotated without the application of heat. The control is adjusted between the various operations merely by the selective operation of a plurality of push-buttons. In both the clothes drying operations the control turns the dryer off automatically when the clothes have fully dried. In the clothes sprinkling operation the dryer may be set to run for any desired length of time, and in case it is desired to damp dry clothes the dryer may be set to run for a predetermined length of time also in both the clothes drying operations. If the dryer door should be opened in any of the operations, the tumbling drum and the heater are turned off thereby to provide operator safety. However, the relay of the control is not de-energized whereby the dryer is automatically placed back in operation when the door is reclosed without any further operation by the operator being required.

While in accordance with the patent statutes I have described what at present is considered to be the preferred embodiment of my invention, it will be obvious to those skilled in the art that various changes and modifications may be made therein without departing from the invention, and I, therefore, aim in the appended claims to cover all such changes and modifications as fall within the true spirit and scope of my invention.

What I claim as new and desire to secure by Letters Patent of the United States is:

1. In a clothes dryer; clothes tumbling means; a drive motor for driving said clothes tumbling means; a heater for heating the clothes being tumbled; and control means for controlling said motor and said heater to produce selectively a controlled heat clothes drying operation, a high heat clothes drying operation, and a clothes tumbling operation without heat, said control means comprising a timer mechanism including a plurality of timer operated switches; a motor circuit including one of said timer operated switches; and a heater circuit, said heater circuit including another of said timer operated switches, a heater cycling thermostat for cycling said heater, thereby to produce said controlled heat clothes drying operation, a normally open manually operable shunt switch con nected in parallel circuit relation with the contacts of said thermostat for shunting said thermostat, thereby to operate said heater continuously for said high heat clothes drying operation, and a normally closed manually operated heater switch arranged for de-energizing said 13 heater thereby to produce said clothes tumbling operation without heat.

2. In a clothes dryer; clothes tumbling means; a drive motor for driving said clothes tumbling means; a heater for heating the clothes being tumbled; and control means for controlling said motor and said heater to produce selectively a controlled heat clothes drying operation, a high heat clothes drying operation and a clothes tumbling operation without heat, said control means comprising a timer mechanism including a plurality of timer operated switches; a motor circuit including one of said timer operated switches; a heater circuit, said heater circuit including another of said timer operated switches, a heater cycling thermostat for cycling said heater, thereby to produce said controlled heat drying operation, a normally open manually operated shunt switch connected in parallel circuit relation with the contacts of said thermostat for shunting said thermostat, thereby to operate said heater continuously for said high heat drying operation, and a normally closed manually operated heater switch arranged for deenergizing said heater, thereby to produce said clothes tumbling operation without heat; a plurality of push buttons for operating said heater switch and said shunt switch; and linkage means interconnecting said push buttons whereby operation of one of said heater and shunt switches from its normal position returns the other of said switches to its normal position, with one of said push buttons being eifective to return both of said switches to their normal positions simultaneously.

3. In a clothes dryer; an electrical heater, clothes tumbling means; a drive motor for driving said clothes tumbling means; means for blowing air over said heater and through said clothes tumbling means; and control means for controlling said motor and said heater to produce selectively a controlled heat clothes drying operation, a high heat clothes drying operation and a clothes tumbling operation without heat, said control means comprising a timer mechanism including a plurality of timer operated switches; a motor circuit including one of said timer operated switches; a heater circuit, said heater circuit including another of said timer operated switches, a heater cycling thermostat responsive to the temperature of the inlet air entering said clothes tumbling means from said heater for cycling said heater, thereby to provide said controlled heat clothes drying operation, a normally open manually operated switch connected in parallel circuit relation with the contacts of said thermostat for shunting said thermostat, thereby to operate said heater continuously for said high heat clothes drying operation, a normally closed manually operated heater switch arranged for de-energizing said heater, thereby to produce said clothes tumbling operation without heat, and means including thermostatic means responsive to the temperature of the exhaust air leaving said clothes tumbling means for opening said heater circuit and said motor circuit independently of said timer operated switches when said clothes are fully dried in both said high heat clothes drying operation and said controlled heat clothes drying operation.

4. In a clothes dryer; an electrical heater; clothes tumbling means; a drive motor for driving said clothes tumbling means; means for blowing air over said heater and through said clothes tumbling means; and control means for controlling said motor and said heater to produce selectively a controlled heat clothes drying operation, a high heat clothes drying operation, and a clothes tumbling operation without heat, said control means comprising a timer mechanism including a plurality of timer operated switches; a motor circuit including one of said timer operated switches; and a heater circuit, said heater circuit including another of said timer operated switches, a heater cycling thermostat responsive to the temperature of the inlet air entering said clothes tumbling means from said heater for cycling said heater, thereby to provide said controlled heat clothes drying operation, a normally open manually operated switch connected in parallel circuit relation with the contacts of said thermostat for shunting said thermostat, thereby to operate said heater continuously for said high heat clothes drying operation, and a normally closed manually operated heater switch arranged for de-energizing said heater, thereby to produce said clothes tumbling operation without heat; and means including a pair of thermostats responsive to the temperature of the exhaust air leaving said clothes tumbling means for opening first said heater circuit and then said motor circuit independently of said timer operated switches when said clothes are fully dried in both said high seat clothes drying operation and said controlled heat clothes drying operation.

5. In a clothes dryer; an electrical heater; clothes tumbling means; a drive motor for driving said clothes tumbling means; means for blowing air over said heater and through said clothes tumbling means; and control means for controlling said motor and said heater to produce selectively a controlled heat clothes drying operation, a high heat clothes drying operation and a clothes tumbling operation without heat, said control means comprising a timer mechanism including a plurality of timer operated switches; a motor circuit including one of said timer operated switches; and a heater circuit, said heater circuit including another of said timer operated switches, a heater cycling thermostat responsive to the temperature of the inlet air entering said clothes tumbling means from said heater for cycling said heater, thereby to provide said controlled heat clothes drying operation, a normally open manually operated switch connected in parallel circuit relation with the contacts of said thermostat for shunting said thermostat, thereby to operate said heater continuously for said high heat clothes drying operation, and a normally closed manually operated heater switch connected in series with said thermostat for sle-energizing said heater, thereby to produce said clothes tumbling operation without heat, and means including a relay having contacts in both of said motor and heater circuits and a pair of thermostats responsive to the temperature of the exhaust air leaving said clothes tumbling means for opening first said heater circuit and then said motor circuit independently of said timer operated switches when said clothes are fully dried in both said high heat clothes drying operation and said controlled heat clothes drying operation, one of said exhaust air thermostats de-energizing said relay at a pre-determined high temperature of said exhaust air to open the relay contacts in both of said circuits, and the other of said exhaust air thermostats being connected across the contacts of said relay in said motor circuit and shunting said contacts to continue said motor circuit energized until the dryer temperature has dropped to a suitable level for the removal of the clothes.

6. The combination of claim 5 including a plurality of push buttons for operating said manually operated heater and shunt switches, and linkage means interconnecting said push buttons whereby operation of one of said switches from its normal position turns the other of said switches to its normal position, with one of said push buttons being eifective to return both of said switches to their normal positions simultaneously.

7. In a clothes dryer; an electrical heater; clothes tumbling means; a drive motor for driving said clothes tumbling means; means for blowing air over said heater and through said clothes tumbling means; and control means for controlling said motor and said heater to produce selectively a controlled heat clothes drying operation, a high heat clothes drying operation and a clothes tumbling operation without heat, said control means comprising a timer mechanism including a plurality of timer operated switches; a motor circuit including one of said timer operated switches; and a heater circuit, said heater circuit including a second of said timer operated switches, a heater cycling thermostat responsive to the temperature of the inlet air entering said clothes tumbling means from said heater for cycling said heater, thereby to provide said controlled heat drying operation, a normally open manually operated switch connected in parallel circuit relation with the contacts of said thermostat for shunting said thermostat, thereby to operate said heater continuously for said high heat clothes drying operation, and a normally closed manually operated heater switch connected in series with said thermostat for de-energizing said heater, thereby to produce said clothes tumbling operation without heat; and means including a relay and a pair of thermostats responsive to the temperature of the exhaust air leaving said clothes tumbling means for opening first said heater circuit and then said motor circuit independently of said timer operated switches when said clothes are fully dried in both said high heat clothes drying operation and said controlled heat clothes drying operation, said relay having contacts in both said motor circuit and said heater circuit, and an operating coil for closing said contacts, one of said thermostats de-energizing said coil when said clothes have dried and the other of said thermostat shunting the relay contacts in said motor circuit to produce a cool down period; and safety switch means including a door switch for opening said motor circuit and said heater circuit whenever said door is opened, with said relay coil being energized independently of said motor circuit whereby the relay circuit is not de-energized by the opening of said door but is de-energized only by the opening of said one exhaust thermostat or by the opening of one of the timer operated switches.

8. In a clothes dryer; clothes tumbling means; a drive motor for driving said clothes tumbling means; an electrical heater; means for blowing air over said heater and through said clothes tumbling means; and control means for said heater and said motor comprising a timer mechanism including a plurality of timer operated switches, a relay having a plurality of sets of contacts and a coil for controlling said contacts, a heater circuit including a first of the timer operated switches and a first set of the relay contacts, a drive motor circuit including a second of the timer operated switches and a second set of the relay contacts, a relay circuit for energizing said relay coil including one of the timer operated switches and one set of the relay contacts, a thermostat responsive to the temperature of the exhaust air leaving said tumbling means for breaking said relay circuit when the exhaust air reaches a predetermined high temperature, thereby to tie-energize said coil and open said relay contacts, safety switch means including a door switch for opening said motor circuit and said heater circuit whenever the dryer door is opened, with said relay circuit being energized independently of said motor circuit whereby said relay circuit is not deenergized by the opening of said door but is de-energized only by the opening of said thermostat or by the opening of said one of the timer operated switches.

9. Combination of claim 8 including a manually operated normally open switch connected in parallel with said one set of relay contacts for initially energizing said relay coil to place said dryer in operation.

10. In a clothes dryer; an electrical heater; clothes tumbling means; a drive motor for driving said clothes tumbling means; means for blowing air over said heater and through said clothes tumbling means; and control means for said heater and said motor comprising a timer mechanism including a plurality of timer operated switches, a relay having a plurality of sets of contacts and a coil for controlling said contacts, a heater circuit including a first of the timer operated switches and a first set of said relay contacts, a drive motor circuit including a second of said timer operated switches and a second set of said relay contacts, a relay circuit for energizing said relay coil including one of said timer operated switches and one set of said relay contacts, a first thermostat responsive to the temperature of the exhaust air leaving said tumbling means for breaking said relay circuit when said exhaust air reaches a predetermined high temperature, thereby to open said relay contacts and deenergize said heater and relay circuits, a second thermostat having contacts connected in parallel with said second set of relay contacts in said motor circuit, said second thermostat being also responsive to the temperature of said exhaust air and closing its contacts so long as said exhaust air temperature is above a predetermined lower temperature suitable for the removal of clothes from said tumbling means, whereby said motor circuit is not broken with said heater circuit when said relay coil is de-energized but remains energized until said exhaust temperature decreases to said lower value or until said second switch of said timer mechanism is opened, and safety means for opening said motor circuit and said heater circuit when the door of said dryer is opened, said safety means comprising a door switch for opening said motor circuit, and a motor centrifugal switch for opening said heater circuit when said motor ceases operation, with said relay circuit being energized through a back contact of said door switch when said door is open, whereby said relay circuit is not de-energized by the opening of said door.

11. In a clothes dryer; an electrical heater; clothes tumbling means; a drive motor for driving said clothes tumbling means; means for blowing air over said heater and through said clothes tumbling means; and control means for said heater and said motor comprising a timer mechanism including a plurality of timer operated switches, a relay having a plurality of sets of contacts and a coil for operating said contacts, a heater circuit including a first of said timer operated switches and a first set of relay contacts, a drive motor circuit including a second of said timer operated switches and a second set of said relay contacts, a relay circuit for energizing said relay coil including one of said timer operated switches and one set of said relay contacts, a thermostat responsive to the temperature of the exhaust air leaving said tumbling drum for breaking said relay circuit when said exhaust air reaches a predetermined high temperature, thereby to de-energize said coil and open said relay contacts, and a manually operated normally open switch connected in parallel with said one set of relay contacts for initially energizing said relay coil to place said dryer in operation.

12. In a clothes dryer; an electrical heater; clothes tumbling means; a drive motor for driving said clothes tumbling means; means for blowing air over said heater and through said clothes tumbling means; and control means for controlling said motor and said heater to produce selectively a controlled heat drying operation, and a high heat clothes drying operation, said control means comprising a timer mechanism including a plurality of timer operated switches; a motor circuit including one of said timer operated switches; and a heater circuit, said heater circuit including another of said timer operated switches, a heater cycling thermostat responsive to the temperature of the inlet air entering said clothes tumbling means from said heater for cycling said heater, thereby to provide said controlled heat drying operation, and a normally open manually operated switch connected in parallel circuit relation with the contacts of said thermostat for shunting said thermostat, thereby to operate said heater continuously for said high heat drying operation; and means including a thermostat responsive to the temperature of the exhaust air leaving said clothes tumbling means for opening said heater circuit and said motor circuit independently of said timer operated switches when said clothes are fully dried in both said high heat clothes drying operation and said controlled heat clothes drying operation.

137 In a clothes dryer; clothes tumbling means; a drive motor for driving said clothes tumbling means; an electrical heater; means for blowing air over said heater and through said clothes tumbling means; and control means for said heater and said motor comprising a relay having a plurality of sets of contacts and a coil for controlling 17 said contacts, a heater circuit including said heater and a first set of the relay contacts, a drive motor circuit including said drive motor and a second set of the relay contacts, a relay circuit for energizing said relay coil including one set of the relay contacts, a thermostat responsive to the temperature of the exhaust air leaving said tumbling means for opening said relay circuit when the exhaust air reaches a predetermined high temperature, thereby to de-energize the coil and open said relay contacts to terminate the dryer operation, and safety switch means including a door switch for opening said motor circuit and said heater circuit whenever the dryer door is opened, with said relay circuit being energized independently of said motor circuit whereby said relay circuit is not de-energized by the opening of said door but is deenergized only by the opening of said thermostat.

References Cited in the file of this patent UNITED STATES PATENTS 2,505,041 Gorsuch Apr. 25, 1950 10 2,654,160 Peterson Oct. 6, 1953 2,707,837 Robinson et a1 May 10, 1955

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