US3220117A

US3220117A - Dryer control system

Info

Publication number: US3220117A
Application number: US205700A
Authority: US
Inventors: Donald G Lycan
Original assignee: American Motors Corp
Current assignee: American Motors Corp
Priority date: 1962-06-27
Filing date: 1962-06-27
Publication date: 1965-11-30
Anticipated expiration: 1982-11-30

Description

Nov. 30, 1965 D. s. LYCAN DRYER CONTROL SYSTEM 2 Sheets-Sheet 1 Filed. June 27, 62

/0-? 1/06 INVENTOR.

MAM

Nov. 30, 1965 G. LYCAN 3,220,117

DRYER CONTROL SYSTEM Filed June 27. 1962 2 Sheets-Sheet 2 INVENTOR. 170 mm 4. Cyan/Y MAM United States Patent C 3,220,117 DRYER CONTROL SYSTEM Donald G. Lycan, Birmingham, MiclL, assignor to American Motors Corporation, Detroit, Mich., a corporation of Maryland Filed June 27, 1962, Ser. No. 205,700 Claims. (Cl. 3445) This invention relates to laundry appliances applicable for the drying of clothes, fabrics and the like and more particularly to electrical control systems used in such appliances.

It is an object of the present invention to provide a clothes dryer with an improved electrical control system whereby the dryer may be selectively operated to produce a plurality of different clothes treating operations, with a suitable type of control being available for each operation.

Another object of the present invention is to provide an improved control system for a clothes dryer whereby it may be selectively operated to produce a plurality of different operations; a clothes drying operation of timed length with thermostatically controlled heat, a clothes tumbling operation of timed length without heat, and a clothes drying operation whose length is automatically varied to produce the correct drying period for fully drying the clothes with selectable thermostatically controlled heat.

A further object of the present invention is to provide an improved control system for a clothes dryer having a manually adjustable setting to initiate the automatically controlled drying period for fully drying the load placed in the dryer and whereby the manual setting is adjustable to vary the control system so as to auto matically control the drying period in accordance to the type and kind of fabrics that compose the load to be fully dried and is further adjustable to vary the control system to provide the degree of dryness desired.

A still further object of the present invention is to provide a switch and circuit arrangement in a clothes dryer to insure the operation of the preselected automatic drying operation by energizing a timer motor at the initial start for a predetermined period to sufficiently rotate cams to insure the setting of proper timer operated switches and after which the switch is automatically opened to open the circuit and stop the timer motor.

A still further object of the present invention is to provide an improved control arrangement for a clothes dryer including dual temperature responsive controls wherein one may be selectively placed in control of operation through the manual setting of the control knob.

Further objects and advantages of the present inventionwill be apparent from the following description, reference being had to the accompanying drawing, wherein a preferred form of the invention is clearly shown.

FIG. 1 is a vertical view in cross section of a clothes dryer embodying features of my invention,

FIG. 2 is a fragmentary view taken along line 22 of FIG. 1,

FIG. 3 is a schematic diagram of a control system embodying my invention, and

FIG. 4 is a chart showing the sequence of operation of timer operated switches included in the system of FIG. 3.

Shown in the drawings is a clothes dryer 0' comprising in general a casing 12 within which is a drum or tumbler 14 rotatably mounted upon a plurality of rollers 16 which are grouped and arranged to provide a cradle support and a drive for the drum 14. The roll ers 16 are mounted on

shafts

18, 20 respectively, for rotation therewith. The

shafts

18, 20 are extended between spaced parallel

upright walls

22, 24 and are suitably journalled thereto. The shaft 18 is operatively connected to be driven by an electric motor 26 through a belt drive 28. The motor 26 is supported upon a base 30 of the cabinet. The

uprights

22, 24 are secured to the base 30 to extend upwardly therefrom in a spaced relation to a respective end of the drum 14.

The drum 14 comprises a cylindrical Wall 32 and

end walls

34, 36. The

end walls

34, 36 are each formed with a

central opening

38, 40 respectively. The opening 38 is closed by a stationary closure plate 42 secured to the upright wall 22. The peripheral edge of the plate 42 overlaps the end wall 34 and carries a sealing member 44 which is adapted to extend to and frictionally engage the end wall 34. The sealing member 44 extends circumferentially about the opening 38. An opening 46 is formed in the closure plate 42 which forms an outlet for a passage 48 formed in a vertically extended duct 50. The lower end of the duct is open for entrance of air to flow upwardly for conduction therethrough into the drum. Positioned within the passage 48 is an electrical heating element 52.

Fixed to the upright 24 is an annular ring 56 held in spatial relation to the end wall 36 of the drum. Sealing members 58, 60 extend concentrically about the opening 40. Each of the sealing members 58, 60 are secured to the annular ring 56 to extend across for fric-' tional engagement with the end wall 36 of the drum; Protruding through the annular ring and through the opening 40 into the drum is a neck or collar 62. The collar 62 is aligned with an opening formed in a front wall 66 of the casing 10 which serves as an access into the drum to be closed by a suitable door 68. The door 68 is preferably hinged (not shown) to the front wall 66.

A vertically extended duct 70, forming a passage 72, is positioned between the upright wall 24 and the front wall 66. The upper end of the duct is turned to extend laterally adjacent the collar 66 and is provided with an inlet opening 74 through which the interior of the drum is connected in open communication with the passage 72. The lower end of the duct 70 is turned to extend laterally, as at 76, to extend the passage 72 into an inlet of an air moving device or blower 78. A duct con-' nects to extend the outlet of the blower 78 exterior to the casing 10. The blower 78 is operatively connected to be driven by the motor 26.

Suitable openings 82 are provided in the front wall 66 for entry of air to circulate into the casing 10 and from where it is withdrawn to pass upwardly through the duct 50 wherein it is heated by contact with the heating element 52. From the duct 50 the heated air passes into the rotating drum to circulate through the clothes tumbling therein to effect their drying. The moisture laden air passes from the drum through the opening 74 into the passage 72. A screen filter 84 is positioned within the passage 72 adjacent the inlet opening 74 to trap and remove lint and other like matter before the air passes into the blower 78. The blower forces the air to pass outwardly through the conduit 80 to the atmosphere. If desired the conduit 80 may be extended by duct extensions (not shown) whereby the discharge may be at some point remote from the dryer.

The operation of the heating element 52 and the motor 26 is controlled by my new and improved control system 100 which is schematically shown in FIGS. 3 and 4. The control system 100 includes in general a timer 102, a pair of cycling

thermostats including switches

104, 106 respectively, and a safety thermostat including switch 108.

The cycling thermostats with their

switches

104, 106 are shown positioned in the duct 80 adjacent to the outlet of the blower. However, they may be positioned in any other suitable location, as in the end plate 42 to extend into the drum so that they sense to respond to the air temperature within the drum. To de-energize the heating element 52 the switch 104 is actuated when the air temperature has attained preferably 150 F., and the switch 106 is actuated when the air temperature has attained preferably 170 F. The safety thermostat with switch 108 is shown located in the air duct 50 between the heating element 52 and the inlet to the drum 14. The safety thermostatically operated switch 108 is actuated should the selected cycling thermostatically operated

switch

104, or 106, fail to function and the air temperature in the drum begins to rise above 180 F. whereupon the switch 108 will de-energize the heating element 52 to prevent overheating or burning of the clothes within the drum. This will be more fully set out.

The timer 102 is preferably mounted within a housing 110 on the casing 12. The timer 102 comprises a pair of cams 112, 114 which are mounted upon a common shaft 116 for rotation therewith. Secured upon the shaft 116 for rotation therewith is a control knob and pointer 118 to permit manual rotation of the shaft in either a clockwise or a counter-clockwise direction to manually preset the cams. The shaft 116 is operatively connected to be driven in a counterclockwise direction by a timer motor 120. The cam 112 directly engages a switch blade or reed having a contact 130. The periphery of the cam 112 is so arranged (not shown) that at various rotated positions it is adapted to move the contact 130 against a contact 132, or it may effect to move to engage together

contacts

130, 132, 134, or it may effect to move to engage together

contacts

130, 132, 134 and 136. Each of the

contacts

132, 134 and 136 are also suitably mounted on a respective flexible reed, switch blade for the like to effect movement relative to each other. Preferably the reeds are arranged to flex and carry their respective contact out of engagement from the adjacent contact as the cam releases its pressure on the reeds.

The cam 114 directly engages a flexible switch blade or reed having a contact 140 which contact is adapted, by rotation of the cam, to follow the cam due to its flexibility and move in one direction into an engagement with a contact 142, or be moved in an opposed direction by the action of the cam to effect a closing of the contact 140, 144, or contacts 140, 144 and 146 together as required.

Connected to a suitable source of electrical energy are conductors 150, 152, 154. A circuit across the conductor 152 with either conductor 150 or 154 provides current of 115 volts. A circuit across the conductors 150, 154 provides current of a higher voltage, preferably of 230 volts.

The conductor 150 is connected to the timer contact 132. The timer contact 130 is connected by a conductor 156 to the energizing windings 158 of the drive motor 26 which in turn is connected by a conductor 160 to a door operated switch 162. The door switch 162 is connected to the conductor 152.

The

timer contacts

134, 136 are each connected to a switch arm of the thermostatically operated switch 104. The contact 136 is connected directly by a conductor 166 to the switch arm 170. The contact 134 is connected to the switch arm 170 by a conductor 169 to a manually operated switch 168 and the conductor 166.

The thermostatically operated switches 104, .106, 108 are similar in construction. The switches are each shown as being preferably a single throw double pole type. The switch 104 comprises the switch arm 170 movable selectively between

contacts

172, 174. The switch. 106 comprises a switch arm movable selectively between contacts 182, 184. The switch 108 comprises a switch arm 186 movable selectively between

contacts

188, 190. Each of the

switch arms

170, 180, 186 is connected to respective thermostats (not shown) for being biased thereby in response to respective air temperature values within the drum. Normally in the switch 104 the switch arm 170 engages the contact 172 until the air temperature attains a predetermined value, preferably 150 F., whereupon the switch arm moves from contact 172 to engage upon the contact 174. For the switch 106 the switch arm normally engages the contact 182until the air temperature reaches a predetermined value, preferably 170 F. whereupon the arm 180 will selectively engage the opposing contact 184. In the switch 108 the normally engaged contact 188 is disengaged by the switch arm 186 to move and engage the contact when the air temperature reaches a predetermined value, preferably 180 F.

As the air temperature cools within the drum to fall to a predetermined low value each of the

switch arms

170, 180, 186 will at a respective temperature value, preferably between 140150 F., be actuated to selectively return to normal position to re-engage its

respective contacts

172, 182, 188.

The contact 172 of the switch 104 is connected by a conductor 200 to the contact 182 which in turn is connected by a conductor 202 to the switch arm 186 of the safety thermostat. The contact 188 is connected by a conductor 204 to one side of a centrifugally operated switch 206 positioned within the motor 26. The opposite side of the switch 206 is connected by a conductor 208 to the heating element 52 which in turn is con nected to the conductor 154.

One terminal of the timer motor 120 is connected to the power source through a conductor 153, door switch 162 to the conductor 152. The other terminal of the timer motor is connected by a conductor 212 to the contact 142, and by a conductor 214 to the contact 174 of the thermostatic switch 104. The

respective switch contacts

174, 184 and 190 are connected together in series circuit by a conductor 216.

The contact 130 is connected by a conductor 218 to the contact 140. The contact 144 is connected by a conductor 220 to the switch arm 180 of the thermostatic switch 106. The contact 146 is connected by a conductor 222 to the contact 142.

Associated with the contact knob and pointer 118 of the timer 102 is a stationary dial 230. The face of the dial 230 is marked, or divided into

sections

232, 234, 236. Rotating the knob so that the pointer is stopped in either the

section

232 or 234 sets the control system to provide a temperature modified clothes drying operation which automatically determines the drying period to fully dry the clothes. The section 232, marked W W, is preferably for the drying of clothes and fabrics which are generally known as Wash-Wear, that is, the fabrics are of synthetic material having the characteristics of absorbing little or no moisture so that to dry requires chiefly the evaporation of the surface moisture therefrom as opposed to fabrics of organic material, such as cotton or wool, which absorb moisture. For drying the latter fabrics the knob 118 is rotated with its pointed set within the section 234. The section 234 (noted as Regular in FIG. 4) is subdivided into preferably three subsections marked as L, N and H. The subsections permit the user to vary the automatically determined drying period to correspond to the moisture absorbing qualities of the articles composing the load. The position marked L is for a load wherein the articles composing the load are of thin or delicate fabrics as opposed to the other extreme section marked H which is designated for a load composed of heavy moisture absorbing articles such as hand rugs, bedspreads and the like.

In each of the

sections

232, 234 the user is further permitted to adjust the control system to a finer setting to provide for the individuals own degree of dryness requirement. That is, each individual has a personal requirement as to the degree of dryness that is suitable for folding and storing, or a dryness suitable for ironing and the like. In each requirement some percentage of natural moisture retention is desired in the clothes as opposed to a so called bone dry condition which is found to be undesirable as the fabric is then without its natural moisture and this makes the fabric feel harsh to the touch, and brittle. Further, it is also necessary to adjust the control system for garments that have heavy seams, lapped or folded over sewed sections that dry slower. The control system can be varied to provide the degree of dryness required by adjusting the starting setting through the positioning of the pointer in the selected

section

232 or 234. When the pointer is set midway in the section 232, or midway in either of the subsections L, N or H in section 234, an average degree of dryness is had for the respective load, but if the setting is varied towards either extreme in the respective section a corresponding change is had in the degree of dryness. The percentage of natural moisture retained in the garments will proportionally decrease as the starting setting is advanced in the selected section towards the extreme end furthest from the off position.

A rotation of the knob and pointer 118 for a setting within the section 236 provides a timed drying period of a timed length as preselected. The duration or length being in accordance to the graduated setting to which the pointer is set, each graduation provides a respective preselectable time duration.

Rotating and setting the pointer 118 into any sector on the dial 230 rotates and positions the cams 112, 114 to preset respective contacts which are graphically shown in FIG. 4. The period of interengagement of the contacts during the operation of the control system is represented by cross hatching and will be more fully explained hereinafter.

Setting the knob and pointer 118 into any portion of the section 232 correspondingly rotates and positions the cams 112, 114 to actuate the following respective contacts and close the following respective circuits. The cam 112 closes the contact 130 upon the contact 132 and thereby closing a circuit to energize the drive motor 26. The cam 114 closes the contact 140 upon the contact 144 to select the thermostatic switch 106 to control the energization of the heating element 52. The motor energizing circuit is as follows: the conductor 150, the

closed contacts

130, 132, the conductor 156, motor windings 158 of the motor 26, the conductor 160, the closed door operated switch 162 and the conductor 152. The circuit energizing the heating element is as follows: the conductor 150,

closed contacts

132, 130, conductor 218, the closed contacts 140, 144 conductor 220, switch arm 180 to contact 182 of the cycling thermostatic switch 106, conductor 202, switch arm 186 to contact 188 of the safety thermostatic switch 108, conductor 204, the closed centrifugal operated switch 206 within the motor 26, conductor 208, the heating element 52 and the conductor 154. The following automatic drying action is initiated.

The heated air enters the rotating drum to circulate about and through the tumbling wet articles or clothes, and the moisture laden air is then Withdrawn from the drum by the blower 78 to be passed to the atmosphere. A portion of the heated air circulating about the tumbling clothes is applied to raise the temperature of the clothes and a portion of the heated air will tend to vaporize the moisture present on and in the clothes. The effect of the latent heat to vaporize the moisture acts to reduce the temperature of the clothes. Eventually a balanced condition is reached between the increase in sensible heat and the cooling effect of vaporization to temporarily stop the rise in air temperature Within the drum so that for a period thereafter the clothes will continue to dry at a constant temperature. The length of this period and the temperature value at which the drying for this period occurs will of course vary for different loads being dependent upon the quantity of articles, the heat input, the air flow and the wetness of the articles. As the drying period continues the surface moisture is reduced which in turn reduces the cooling effect due to vaporization. This results in a rapid increase in the temperature of the clothes with a resultant increase in the exhaust air until it reaches a temperature value to effect actuation of the switch 106. In the present instant the switch 106 is preferably actuated when the air temperature reaches. 170 F. whereupon the switch arm 180 disengages from the contact 182 to deenergize the heating element 52 and is biased to engage upon the contact 184 to energize the timer motor through a circuit as follows: conductors 150,

closed contacts

132, 130, conductor 218, closed contacts 140, 144, the conductor 220, the switch arm 180 to contact 184, the conductors 216, 214, the timer motor and the conductor 153 through the closed door switch 162 to the conductor 152. The operation of the timer motor rotates the cams 112, 114.

It is preferred in this drying operation, section 232, that after the timer motor has been energized a short period that it rotate the cam 114 to permit the contact 140 to bias away from the contact 144 and engage upon the contact 142 before there is a sufficient cool down to thermostatically effect an actuation of the switch 106 to reclose the heater contact. In some instances there may be a rapid cool down in which case the switch 106 will be actuated to re-energize the heating element a second time and de-energize the timer motor. Normally the timer motor on its first run will fully rotate the cam 114 to bias the contact 140 away from the contact 144 and upon 142. This will change the timer motor circuit to be as follows: conductor 150,

closed contact

132, 130, conductor 218, closed contacts 140, 142, conductor 212, timer motor 120 and conductors 153, 152 through the closed door switch 162. This latter circuit will insure that the timer motor will rotate the cams to first effect a cool down period wherein the drive motor 26 continues rotating the drum and to drive the blower to circulate unheated air through the tumbling clothes. A predetermined period thereafter the cams 112, 114 have been rotated to permit contact to separate from contact 132 to stop the motor 26, and to be followed by the contact separating from the contact 142 whereupon the timer motor is stopped with the cams having been rotated to effect separation of all the contacts and the opening of all of the circuits. The pointer 118 will have been rotated and halted in the stop section 240 on the dial.

In the above described drying operation, preferably adapted for Wash-Wear fabrics, it is desirable that the fabrics be dried in high heat with preferably only a single energizing period for the heating element as the moisture is mostly surface moisture which when evaporated the fabric becomes fully dried. In the automatic drying cycle as described above once the air temperature attains the predetermined high value the surface moisture on Wash- Wear fabrics is generally completely evaporated. However other fabrics that absorb moisture, as previously explained, require low heat with successive stages of heater on to both evaporate the surface moisture and drive out the absorbed moisture. For this latter type of fabric load the pointer 118 is set within the section 234 on the dial 230.

In section 234 whether the pointer is set for L, N or H the automatic operation and the switch settings are the same, the variance is in the timed length of the drying operation, that is, the period of operation for the timer motor. This will be more fully set out hereinafter.

Assume the pointer 118 is set in section 234 in the subsection marked as N on the dial. The cams 112, 114 are manually preset so that the cam 112 actuates to bias or close together the

contacts

130, 132, 134 and 136. The cam 114 actuates no contacts at this time. The

closed contacts

130, 132 close the same identical circuit to energize the motor 26 as described above when the pointer 118 was set in section 232. Through the contact 136 there is closed a circuit to energize the heating element 52 under control of the cycling thermostatic switch 104 as follows: conductor 150,

closed contacts

132, 134, 136, conductor 166, switch arm 170 to contact 172 of the cycling thermostatic switch 104,

conductors

200, 202, switch arm 186 to contact 188 of the safety thermostatic switch 108, conductor 204, closed centrifugally operated switch 206, conductor 208, the heating element 52 and the conductor 154.

The heated air will circulate through the tumbling clothes and the initial drying period will be as previously explained above when the knob was set in the section 232. A portion of the heat will be applied to raise the temperature of the clothes and a portion to vaporize the moisture on and in the clothes until eventually a balance is reached between the increase in sensible heat and the cooling effect of vaporization so that for a period thereafter the clothes will be dried at a constant temperature value. As the surface moisture decreases there is an increase in the tem perature of the clothes with a resultant increase in the exhaust air to influence the actuating of the switch arm 170 of the thermostatic switch 104 when the air temperature attains preferably 150 F. The movement of the switch arm 170 from contact 172 de-energizes the heating element 52 and upon engaging the contact 174 energizes the timer motor 120 through the conductors 214, 153 and 152 through the closed door switch 162.

The energized timer motor will operate to rotate the cams 112, 114 in a counter-clockwise direction until the air temperature drops below a predetermined value whereupon the switch 104 will be thermostatically actuated to bias the switch arm back to the contact 172 to re-energize the heating element and de-energize the timer motor. Meanwhile the drive motor 26 will continue to run uninterrupta-bly to tumble the clothes and circulate the heated or unheated air. This cycling will continue until the total timers on time is sufficient to advance the cams to the cool down section and thereafter terminate the drying cycle. In the progressive drying of the clothes each heater on will be shorter in duration, and each successive heater off will be longer. The timer motor will therefore be on for longer periods as the clothes become dryer. This results in a drying cycle that is partially self-compensating for the variations in the moisture content of each load. By manually setting the pointer in a proper portion of the section 130 in accordance to the load or type of load placed in the dryer the timer cams are preset to provide for the necessary longer or shorter period of drying time to provide for the natural moisture retention as desired by the user.

The cycling air heatingperiod terminates when the cam 112 has been rotated to effect a separation of the

contacts

134, 136. At this time the contact 130 remains in engagement with the contact 132 to continue energizing the motor 26 for a predetermined longer period. Just prior to the separation of

contacts

134, 136 the cam 114 has rotated to effect the closing of contact 140 upon 142 to close an alternate circuit to energize the timer motor for a predetermined concluding cool down operational period after which period all operations will cease. This circuit follows from conductor 152,

closed contacts

132, 130, conductor 218, closed contacts 140, 142, conductor 212, timer motor 120, conductors 153, 152 through the closed door switch 162. During this cool down operational period the clothes are tumbled and cooled by circulating unheated air therethrough. At the end of this period the cams 112 and 114 will effect a separation of the

contacts

130, 132 and the contacts 140, 142 respectively. This concludes the automatic drying period with all circuits being opened and the knob being rotated to halt in the stop section 242 on the dial 230.

It is to be noted that in the above described automatic drying operation the timer motor is first initiated in operation by the cycling thermostat after a maximum air temperature within the drum has been attained. It has been found that by this arrangement the operator, when desiring the full or maximum drying period in either of the two selectable automatic drying operations, may so manually rotate and stop the pointer 118 whereby the cams are at the marginal setting point for initiating actuation of the switches or contacts without fully actuating all of the necessary contacts. Particularly can such a condition occur where there is an allowance permitting a slight play or movement between the cam and shaft, and the manual rotation for setting the cam is being made counter-clockwise. As the operator sets and momentarily holds the pointer at the marginal starting point the cam 112 will hold close the contacts 132, to start the motor 26 and thereby effect a closing of the centrifugal switch 206. As soon as the pointer is released by the operator the cam may backlash to effect a re-opening of the

contacts

132, 130 with the following results for the automatic drying operations.

Assume the preselection is for the Wash-Wear operation, a setting in the section 232. The initial period of operation of the motor 26, before the

contacts

130, 132 reopen, will close the switch 206 and with the closed preset contacts 140, 144 will form a circuit connecting the heating element 52 and the drive motor 26 in series circuit through the

thermostatic switches

106, 108 across the conductors 152, 154. This circuit will allow the motor 26 to continue operating, even though

contacts

130, 132 are separated, and the heater to function inefficiently. As the heating element is in a low voltage circuit it will not provide sufficient heat to effect thermostatic action. This ineffective operation would continue until noticed by the operator who then would be required to manually advance the timer by further counter clockwise rotation of the knob.

The heating element 52 is of the high voltage type hav ing a low resistance, preferably 10 ohms. Because of the low voltage drop across a heating element of this type the motor 26 will operate in series connection therewith as explained above. Further, it will also permit the operation of the timer motor therewith, as will be explained hereinafter.

To automatically correct and automatically advance the timer when the above described condition occurs the contacts 140, 144 are closed down upon the contact 146 by the cam 114 prior to the action of the cam 112 as to its respective contacts (see FIG. 4). The closed contacts 140, 144, 146 preset a circuit to the timer motor 120 so that should the above backlash occur the timer motor will also be simultaneously energized in a parallel circuit with the drive motor. The timer motor circuit follows from conductor 154, heating element 52, switch 108, conductor 20.2, switch 106, conductor 220, closed contacts 144, 146, conductor 212, timer motor 120 and conductors 153, 152. After a short interval of timer motor operation the cam 112 will be advanced to effect a reclosure of

contacts

130, 132 and thereafter the cam 114 will have been advanced to effect a separation of the contacts 146,

9 144 to halt operation of the timer motor. Thereafter the timer motor is alternately energized with the heating element by action of the thermostatically operated switch 106.

Assume the preselection is for the regular automatic operation (see FIG. 4), a setting in section 234 on the dial. The contacts 140, 144, 146 are provided to be preset closed prior to the actuation of the contacts by the cam 112 when the cams are rotated counterclockwise for a presetting. Should a backlash occur to reopen the

closed contacts

130, 132, 134 the same circuit would be had as explained above for energizing the timer motor simultaneously with the series energized motor 26 and heating element 52. However, the cam 112 may only close

contacts

130, 132 but fail as to contact 134 in which case the motor circuit will be closed simultaneously with the timer motor circuit. The timer motor circuit here would follow from conductor 150, across

closed contacts

132, 130, conductor 218, closed contacts 140, 144, 146,

conductors

222, 212, the timer motor 120 and conductors 153, 152. After a predetermined period of timer operation the contacts 140, 144, 146 are separated by the advancement of the cam 114 from each other (see FIG. 4). This arrangement permits the timer motor operation only for a duration to insure that the cams have been rotatably advanced and preset to properly actuate and close the required contacts to provide the required circuits for the preselected dryer operation.

Rotatably setting the pointer 118 within the section 236 of the dial initiates a straight time controlled operation for either heated air drying or unheated air tumbling operation. The length or duration of the period being that as selected by the user in setting the pointer to a time designated graduation. The timer motor will be energized from the moment the pointer is set within the section 236 and will continue to run uninterruptingly for the pre selected time period after which all operations are halted and all circuits opened. The thermostatic switch 104 cycles the heating element 52 to provide for heated air circulation. To provide for heated air circulation the switch 168 must be manually closed. Manually opening the switch 168 provides an unheated tumbling or fiuffing operation.

With the pointer rotated and set in the section 236 and the manually closing of the switch 168 to provide a heated air drying operation the following switches and circuits are closed. The manual presetting of the cam 112 actuates and closes the

contacts

130, 132 and 134 together. The

closed contacts

130, 132 close an already described circuit to energize the motor 26 to operatively rotate the drum and drive the blower. The heaing element 52 is energized through a circuit as follows: conductor 150,

closed contacts

132, 134, conductor 169, closed switch 168, across switch arm 170 and contact 172 of the cycling thermostatic switch 104,

conductors

200, 202, the safety thermostatic switch 108, conductor 204, the closed centrifugtally operated switch 206, the conductor 208, the heating element 52 and the conductor 154. The movement of the switch arm 170 of the thermostatic switch 104 from contact 172 to 174 merely interrupts the circuit to the heating elements. The timer motor circuit is also closed by the manual setting of the cam 114 biasing the contact 140 upon the contact 142 which completes the circuit from the conductor 150,

closed contacts

132, 130, conductor 218, closed contacts 140, 142, conductor 212, the timer motor 120 and conductor 152. The rotation of the cams by the timer motor determines the drying period, and as the cam 112 approaches the terminable end for the drying period the cam 112 will effect a separation of the contact 134 from 132 to open the circuit to the heating element 52 to terminate the air heating period. For a period thereafter the clothes will be tumbled with unheated air circulated therethrough to effect a cooling of the clothes. Following this period the cam 112 will effect the separation of the

contacts

130, 132, and the cam 114 10 will simultaneously effect the separation of the contacts 140, 144 to stop the drive motor 26 and the timer motor respectively. The pointer of the knob 118 having been rotated by the timer motor will be stopped in the adjacent off position 244 on the dial 230.

To provide for a fluffing operation the pointer 118 is set in the section 236 to a graduation for a preselected time period as desired. The switch 168 is manually operated to open position. The timer motor is energized for continuous operation by the closing of the contacts 140, 144, and the drive motor is energized by the closure of the

contacts

130, 132 in the same manner as described above for the straight time operational drying period. The operation is likewise similar except that with the switch 166 in open position the air heating element 52 is not energized and the clothes are tumbled with unheated air circulated therethrough for a preselected period.

The door operated switch 162 is mounted to the cabinet (not shown) to be actuated by the opening and closing of the door 68. The opening of the door 68 actuates the switch to an open position which prevents the starting of any of the drying operations described above, or will during the drying period break the motor circuit so as to deenergize and stop the motor 26. Stopping the motor 26 will actuate the internal switch 206 to open so as to deenergize the heating element 52. Reclosing the door recloses the switch 162 to restart the running of the motor 26 and its operation will through centrifugal action reclose the switch 206 to re-energize the heating element. The timer motor operation is also affected by the door switch 162. For example, in the automatic drying operation,

sections

232, 234 on the dial, should the door he opened when the timer motor 120 is running, it will stop running while the door is held open. Upon reclosing of the door the cycling thermostat may call for heat whereupon the timer motor will remain de-energized until the thermostat is again satisfied before re-energizing the timer motor. Reclosing the door will restart the circulating and tumbling operation, and any cool down will automatically be compensated for by returning the air temperature to the desired value which is a balance between the increase in sensible heat and the cooling effect of vaporization within the dryer before the timer motor will be re-energized. Interrupting the air heating cycle period by the opening of the door 68 will continue the air heating cycle upon the reclosing of the door irrespective whether the drying operation was initiated in

section

232, 234 or 236.

From the above it will be noted that there is provided a control system for a clothes dryer where the user is permitted a choice of methods for the drying of clothes by either fully drying automatically, or drying to a degree of dryness by a predetermined selection of the drying period. Further, the user may adjust the control system to automatically compensate for the quantity, type and kind of fabrics and clothing that are to be fully dried automatically. Also there is provided a control arrangement to insure the starting and operation of the automatic drying operation when the control is manually set at the marginal starting point for the maximum drying ,period desired for slow drying articles.

Although only a preferred form of the invention has been illustrated, and that form described in detail, it will be apparent to those skilled in the art that various modifications may be made therein without departing from the spirit of the invention or from the scope of the appended claims.

I claim:

1. In a clothes dryer, clothes tumbling means, air moving means for circulating air through said clothes tumbling means, a drive motor for driving said clothes tumbling means and said air moving means, a heating element for heating the air circulating through said tumbling means, a control system including a timer and a motor for driving said timer for controlling said drive 1 1 motor and said heating element to produce selectively; a plurality of temperature modified clothes drying operations wherein said timer operates only after the dryer temperature rises to a predetermined high temperature, and a timed clothes drying operation, a pair of thermostatically operated switches each having heater contacts and timer contacts and being adapted to alternately open said heater contacts and close said timer contacts, the first of said thermostatically operated switch being re sponsive to a predetermined higher air temperature than the second switch to open its respective heater contact and close its respective timer contact, and each of said first and second thermostatically operated switches Opening said timer contact and reclosing said heater contact when said air temperature falls to a respective predetermined low temperature, said control system including switch means comprising a first group of first, second and third contacts being adapted to be actuated for selective inter engagement by said timer, and a second group of fourth, fifth and sixth contacts with said fourth contact movable by said timer to selectively engage said fifth and sixth contacts; a first circuit for energizing said drive motor through closing said first upon said second contacts, a second circuit energizing said heating element being connected'with said heater contact of said second thermostatically operated switch and the closing of said first group of contacts, a third circuit energizing said heating element being connected with said heater contact of said first thermostatically operated switch and the closing of said fourth upon said fifth contact, a fourth circuit energizing said timer motor being connected with said fourth contact closing upon said sixth contact, a circuit interconnecting said timer contacts of said first and second thermostatically operated switches and said timer motor, said timer having different presettable operating ranges and operating said contacts to produce selectively a first temperature modified clothes drying operation to provide said first and third circuits, a second temperature modified clothes drying operation to provide said first and second circuits, a timed drying operation to provide said first, second and fourth circuits, said presettable operating ranges of said timer having means arranged to operatively control said second and said third circuits wherein the selection of one of said circuits being provided with a longer period for energization of the heating element than the selection of the other circuit, and a rotatable knob for adjusting said timer to adjust said control system to produce the desired one of said operations.

2. In a clothes dryer, clothes tumbling means, air moving means for circulating air through said clothes tumbling means, a drive motor for driving said clothes tumbling means and said air moving means, a heating element for heating the air circulating through said tumbling means, a control system including a timer and a motor for driving said timer for controlling said drive motor and said heating element to produce selectively; a plurality of temperature modified clothes drying operations wherein said timer operates only after the dryer temperature rises to a predetermined high temperature, and a timed clothes drying operation, a pair of thermostatically operated switches each having heater contacts and timer contacts and being adapted to alternately open said heater contacts and closing said timer contacts, the first of said thermostatically operated switch being responsive to apredetermined higher air temperature than the second switch to open its respective heater contact and close its respective timer contact, and each of said first and second thermostatically operated switches opening said timer contact and reclosing said heater contact when said air temperature falls to respective predtermined low temperatures, said control system including switch means comprising a first group of first, second and third contacts being adapted to be actuated for selecfive interengagement by said timer, and a second group of fourth, fifth and sixth contacts with said fourth contact movable by said timer to selectively engage said fifth and sixth contact; a switch manually operable between open and closed position, a first circuit for energizing said drive motor through. closing said first upon said second contacts, a second circuit energizing said heating element being connected with said heater contact of said second thermostatic switch, said switch manually set in closed position and through the closing of said first group of contacts, a third circuit energizing said heating element being connected with said heater contact of said first thermostatically operated switch and through the closing of said fourth upon said fifth contact, a fourth circuit energizing said timer motor being connected with said fourth contact being closed upon said sixth contact, a circuit interconnecting said timer contacts of said first and second thermostatically operated switches and said timer motor, said timer having different presettable operating ranges and operating said contacts to produce selectively a first temperature modified clothes drying operation to provide said first and third circuits, a second temperature modified clothes drying operation to provide first and second circuits wherein said switch is preset in closed position, a timed drying operation or a timed tumbling operation without heat to provide said first, second and fourth circuits wherein said manually operable switch is preset in closed position for a timed drying operation and preset in open position for timed tumbling operation, said presettable operating ranges of said timer having means arranged to operatively control said second and said third circuits wherein the selection of one of said circuits being provided with a longer period for energization of the heating element than the selection of the other circuit, and a rotatable knob for adjusting said timer to adjust said control system to produce the desired one of said operations.

3. In a clothes dryer, clothes tumbling means, air moving means for circulating air through said clothes tumbling means, a drive motor for driving said clothes tumbling means and said air moving means, a heating element for heating the air circulating through said tumbling means, a control system including a timer and a motor for driving said timer for controlling said drive motor and said heating element to produce selectively; a plurality of temperature modified clothes drying operations wherein said timer operates only after the dryer temperature rises to predetermined high temperatures, a timed clothes drying operation, and a timed clothes tumbling operation without heat, a pair of thermostatically operated switches connected in series and each having heater contacts and timer contacts and being adapted to alternately open said heater contacts and close said timer contacts, the first of said thermostatically operated switch being responsive to predetermined higher air temperatures than said second switch to open its respective heater contact and close its respectively timer contact, and each-of said first and second thermostatically operated switches opening said timer contact and reclosing said heater contact responsive to respective predetermined low temperatures, said control system including switch means comprising a first group of first, second, third and fourth contacts being adapted to be actuated for selective interengagement by said timer, and a second group of fifth, sixth and seventh contacts with said fifth contact movable by said timer to selectively engage said sixth and seventh contact; a first circuit for energizing said drive motor being connected through closing said first upon said second contacts, a second circuit energizing said heating element beingconnected to said heater contact of said second thermostatically operated switch and through the closing of said first group of four contacts, a third circuit energizing said heating element being connected with said heater contact of said first thermostatically operated switch and through the closing of said fifth upon said sixth contact, a fourth circuit energizing said timer motor through closing of said fifth upon said seventh contact, a circuit interconnecting said timer contacts of said first and second thermostatically operated switches and said timer motor, a switch manually operated between open and closed position, said switch being connected in series circuit with said third contact and said heater contact of said second thermostatically operated switch, a fifth circuit energizing said heating element being connected with said heater contact of said second thermostatically operated switch through the interengagement of said first, second and third contacts and said manually operated switch in closed position, said timer having different presettable operating ranges and operating said contacts to produce selectively a first temperature modified clothes drying operation to provide said first and third circuits, a second temperature modified clothes drying operation to provide said first and second circuits, a timed drying operation to provide said first, second, and fourth circuits, a timed tumbling operation without heat to provide said first, fourth and fifth circuits wherein said manually operated switch is in open position, said presettable operating ranges of said timer having means arranged to operatively control said second and third circuits wherein the selection of one of said circuits being provided with a longer period for energization of the heating element than the selection of the other circuit, and a rotatable knob for adjusting said timer to adjust said control system to produce the desired one of said operations.

4. In a clothes dryer, clothes tumbling means, air moving means for circulating air through said clothes tumbling means, a drive motor for driving said clothes tumbling means and said air moving means, a heating element for heating the air circulating through said tumbling means, a control system including a timer and a motor for driving said timer for controlling said drive motor and said heating element to produce selectively: a plurality of temperature modified clothes drying operations wherein said timer operates only after the dryer temperature rises to a predetermined high temperature, and a timed clothes drying operation; a plurality of thermostatically operated switches connected in series and each having heater contacts and timer contacts and being adapted to alternately open said heater contacts and close said timer contacts upon a predetermined high air temperature and opening said timer contacts and reclosing said heater contacts when the air temperature falls to a predetermined low temperature, the first of said thermostatically operated switches being responsive to a predetermined higher air temperature than a second thermostatically operated switch responsive to a predetermined higher air temperature than a third thermostatically operated switch to open its respective heater contact and closing its respective timer contact, said control system including switch means comprising a first, second and third contact being adapted to be actuated for selective interengagement by said timer, and a second group of fourth, fifth and sixth contacts with said fourth movable by said timer to selectively engage said fifth and sixth contacts; a first circuit for energizing said drive motor through closing said first upon said second contacts, a second circuit energizing said heating element being connected with said heater contacts of said first and third thermostatically operated switch in series and through the closing of said first group of contacts, a third circuit energizing said heating element being connected with said heater contact of said first and second thermostatically operated switch in series and through the closing of said fourth upon said fifth contact, a fourth circuit energizing said timer motor through closing of said fifth upon said seventh contact, a circuit interconnecting said timer contacts of each of said thermostatically operated switch and said timer motor, said timer having different presettable operating ranges and operating said contacts to produce selectively a first temperature modified clothes drying operation to provide said first and third circuits, a second temperature modified clothes drying operation to provide said first and second circuits, a timed drying operation to provide said first, second and fourth circuits, said presettable operating ranges of said timer having means arranged to operatively control said second and third circuits wherein the selection of one of said circuits being provided with a longer period for energization of the heating element than the selection of the other circuit, and a rotatable knob for adjusting said timer to adjust said control system to produce the desired one of said operations.

5. In a clothes dryer, clothes tumbling means, air moving means for circulating air through said clothes tumbling means, a drive motor for driving said clothes tumbling means and said air moving means, a heating element for heating the air circulating through said tumbling means, a control system including a timer and a motor for driving said timer for controlling said drive motor and said heating element to produce selectively; a plurality of temperature modified clothes drying operations wherein said timer operates only after the dryer temperature rises to a predetermined high temperature, and a timed clothes drying operation; a plurality of thermostatically operated switches connected in series and each having heater contacts and timer contacts and being adapted to alternately open said heater contacts and close said timer contacts upon a predetermined high air temperature and opening said timer contacts and reclosing said heater contacts when the air temperature falls to a predetermined low temperature, the first of said thermostatically operated switches being responsive to a predetermined higher air temperature than a second thermostatically operated switch, and said second thermostatically operated switch being responsive to a predetermined higher air temperature than a third thermostatically operated switch to open its respective heater contact and closing its respective timer contact, said control system including switch means comprising a first group of first, second, third and fourth contacts being adapted to be actuated for selective interengagement by said timer, and a second group of fifth, sixth and seventh contacts with said fifth contact movable by said timer to selectively engage said sixth and seventh contacts; a first circuit for energizing said drive motor being connected with closing said first upon said second contacts, a second circuit energizing said heating element being connected with said heater contacts of said first and third thermostatically operated switch in series and through the closing of said first group of contacts, a third circuit energizing said heating element being connected with said heater contact of said first and second thermostatically operated switch in series and through the closing of said fifth upon said sixth contact, a fourth circuit energizing said timer motor through closing of said fifth upon said seventh contact, a circuit interconnecting said timer contacts of each of said thermostatically operated switches and said timer motor, a switch manually operated between open and closed position, said switch being in series circuit interconnecting said heater contact of said second thermostatic switch and third con- 15 and fourthcircuits, a timed tumbling operation without heat to provide said first, fourth and fifth circuit wherein said manually operated switch is in open position, said presettable operating ranges of said timer having means arranged to operatively control said second and third circuits wherein the selection of one of said circuits being provided with a longer period for energization of the heating element than the selection of the other circuit, and a rotatable knob for adjusting said timer to adjust said References Cited by the Examiner UNITED STATES PATENTS Engel 34-45 Hughes 34'45 Raley 34-45 Gray 34-45 Morey 34-45 Berenbaum 34,-45

control system to produce the desired one of said opera- 10 WILLIAM Primary Examiner- NORMAN YUDKOFF, Examiner.

tions.

Claims

1. IN A CLOTHES DRYER, CLOTHES TUMBLING MEANS, AIR MOVING MEANS FOR CIRCULATING AIR THROUGH SAID CLOTHES TUMBLING MEANS, A DRIVE MOTOR FOR DRIVING SAID CLOTHES TUMBLING MEANS AND SAID AIR MOVING MEANS, A HEATING ELEMENT FOR HEATING THE AIR CIRCULATING THROUGH SAID TUMBLING MEANS, A CONTROL SYSTEM INCLUDING A TIMER AND A MOTOR FOR DRIVING SAID TIMER FOR CONTROLLING SAID DRIVE MOTOR AND SAID HEATING ELEMENT TO PRODUCE SELECTIVELY; A PLURALITY OF TEMPERATURE MODIFIED CLOTHES DRYING OPERATIONS WHEREIN SAID TIMER OPERATES ONLY AFTER THE DRYER TEMPERATURE RISES TO A PREDETERMINED HIGH TEMPERATURE, AND A TIMED CLOTHES DRYING OPERATION, A PAIR OF THERMOSTATICALLY OPERATED SWITCHES EACH HAVING HEATER CONTACTS AND TIMER CONTACTS AND BEING ADAPTED TO ALTERNATELY OPEN SAID HEATER CONTACTS AND CLOSE SAID TIMER CONTACTS, THE FIRST OF SAID THERMOSTATICALLY OPERATED SWITCH BEING RESPONSIVE TO A PREDETERMINED HIGHER AIR TEMPERATURE THAN THE SECOND SWITCH TO OPEN ITS RESPECTIVE HEATER CONTACT AND CLOSE ITS RESPECTIVE TIMER CONTACT, AND EACH OF SAID FIRST AND SECOND THERMOSTATICALLY OPERATED SWITCHES OPENING SAID TIMER CONTACT AND RECLOSING SAID HEATER CONTACT WHEN SAID AIR TEMPERATURE FALLS TO A RESPECTIVE PREDETERMINED LOW TEMPERATURE, SAID CONTROL SYSTEM INCLUDING SWITCH MEANS COMPRISING A FIRST GROUP OF FIRST, SECOND AND THIRD CONTACTS BEING ADAPTED TO BE ACTUATED FOR SELECTIVE INTERENGAGEMENT BY SAID TIMER, AND A SECOND GROUP OF FOURTH, FIFTH AND SIXTH CONTACTS WITH SAID FOURTH CONTACT MOVABLE BY SAID TIMER TO SELECTIVELY ENGAGE SAID FIFTH AND SIXTH CONTACTS; A FIRST CIRCUIT FOR ENERGIZING SAID DRIVE MOTOR THROUGH CLOSING SAID FIRST UPON SAID SECOND CONTACTS, A SECOND CIRCUIT ENERGIZING SAID HEATING ELEMENT BEING CONNECTED WITH SAID HEATER CONTACT OF SAID SECOND THERMOSTATICALLY OPERATED SWITCH AND THE CLOSING OF SAID FIRST GROUP OF CONTACTS, A THIRD CIRCUIT ENERGIZING SAID HEATING ELEMENT BEING CONNECTED WITH SAID HEATER CONTACT OF SAID FIRST THERMOSTATICALLY OPERATED SWITCH AND