US3040441A - Clothes drier lint burner - Google Patents

Description

June 26, 1962 v. J. KUROWSKI CLOTHES DRIER LINT BURNER 2 Sheets-Sheet 1 Filed Feb. 29, 1960 m 2 8 R s 3 3 3 M K O W 3 K a T o m R a w W m n m 1 ma w w M I e f a [1 O J T v V w 4 m 0 4/ a N 1 E 4 y Zr M G 5 h m r w (I! FIDI N m m 4,- 1 n n M 8 n W 2 u u w s m 5/ 7 u 9 g 3 7 l 5 9 ,7 I. I: Z L. a w w w n m L L 4 3 6 E Z Z 2 HIS ATTORNEY June 1962 v. J. KUROWSKI 3,040,441 CLOTHES DRIER LINT BURNER Filed Feb. 29, 1960 2 Sheets-Sheet 2 FIG .2

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INVENTOR. VICTOR :r. KUROWSKl HIS ATTORNEY 3,040,441 CLOTHES DRIER LINT BURNER Victor J. Kurowslri, Louisville, Ky., assignor to General Electric Company, a corporation of New York Filed Feb. 29, 196i Ser. No. 11,698 1 Claim. (ill. 34-79) This invention relates to an electric control arrangement, and more particularly to a control arrangement wherein an induction-type motor controls the energization of an electric mechanism by permitting energization thereof when rotating and preventing it when not rotating,

whether the windings of the motor are energized or not.

There are many instances in the relatively complex machines run by induction-type electric motors wherein a function of the machine is to be desired if the motor is operating effectively, but is not desired if there is no rotation of the motor regardless whether the motor is still receiving electric current or not. This may occur, for instance, in a clothes dryer of the type which has a lint consumer (as described and claimed in copending application Serial No. 7558) filed on February 9, 1960 by Russell 'M. Sasnett, and assigned to the same assignee as the present application) wherein consumption of the lint is effected by a high voltage spark provided by a step-up transformer. In such a case, it is important for reasons of safety and proper functioning of the machine that the high-voltage spark be provided only when the motor which provides the air draft is operating effectively at the desired speed. Heretofore, the control of additional mechanisms has in volved either the provision of additional switch mechanisms, or at the very least the addition to existing switch mechanisms of additional contacts and the like, thereby complicating the structure over what would be required without the control of the device. Manifestly, the cost of the machine in which such a device is incorporated is dependent to some extent upon the addition of elements for control purposes.

It is therefore an object of my invention to effect control of an electrically actuated mechanism in response to the operation of an induction-type electric motor by so connecting the mechanism to the motor that it will be operative only when the motor is running.

A further object of my invention is to incorporate an improved structure of the type mentioned immediately hereabove in a clothes dryer having a lint consumer, so that there can be no operation of the lint-consuming apparatus without effective running of the motor which causes a draft of air to be passed through the apparatus.

More specifically, it is an object of my invention to so connect a relatively high-impedance electric device in combination with an induction motor of the type having relatively low-impedance start and main windings and a speed-responsive mechanism to open the start winding when the motor comes up to speed, so that the operation of the electrical device is dependent upon the opening of the mechanism, this being effected without the addition of any switch mechanism, or back contacts.

Briefly-stated, in accordance with one aspect of my invention, I provide in combination a relatively high-impedance electrical device and an induction-type motor having relatively low-impedance main and start windings, with both the device and the motor being included in a cir. cuit connected across first and second supply conductors.

, 3,040,441 Patented June 26, 1,962

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Each of the main and start windings has one end connected to the first supply conductor, and the main winding has its other or second end connected to the second supply conductor so as to be energized across them. Conventional speed-responsive switch means is permanently connected to the second end of the main winding, and is also connected to the other, or second, end of the start winding but only up to a predetermined speed at which it becomes disconnected from the start winding. I connect the electrical device between the second end of the run winding and the second end of the start winding, so that when the speed-responsive switch mechanism opens the circuit which connects the start winding directly across the supply conductors, a circuit continues to be completed through the start winding in series with the electrical device so as to provide for energization of the electrical device. As soon as the motor slows down or stops for any reason whatsoever, the start speed responsive switch moves back to its stop position in which it shorts out the electrical device and connects the start winding in its starting posiself, however, both as to its organization and method of operation may best be understood by reference to the following description taken in conjunction with the accompanying drawings.

In the drawings, FIGURE 1 is a side elevational view of a clothes drying machine which may include my inven tion, the view being partially broken away and partially in section to illustrate details;

FiGURE 2 is a schematic illustration of a control circuit for the machine of FIGURE 1 incorporating my invention; and

FIGURE 3 is a schematic illustration showing a second embodiment of my invention;

Referring now to FIGURE 1, I have shown therein a domestic clothes dryer 1; the dryer includes a clothestumbling receptacle or drum 2 provided within a suitable outer casing or cabinet 3 which completely encloses it on all sides. The drum is mounted for rotation within the cabinet on a substantially horizontal axis, and is generally cylindrical in shape, having a first central outer wall portion 4, second and third outer wall portions 5 and 6 located respectively adjacent the ends of the drum, a back wall 7 and a front wall 8. Outer wall sections 4, 5 and 6 are imperforate over their entire length, so that the entire outer shell of the drum 2 is imperforate; on the interior surface of central portion 4 there 'is provided a plurality of clothes tumbling ribs 9.

The front of drum 2 is rotatably supported on the outer casing by means of a pair of idler rollers, one of which is shown by the number 10, which are rotatably secured to the top of an upwardly extending member 11 fastened at its bottom to the base 12. The rollers 10 are disposed beneath the drum in contact with portion 6 thereof so that the drum. is supported on the rollers at its front end and is free to rotate. The rear end of drum 2 receives its support from a roller wheel 13 which is positioned beneath portion 5 of the drum in supporting and frictionally driving engagement therewith.

Roller 13 is mounted on a shaft 14 supported in bearings 15. At one end of shaft 14 is secured a pulley 16 driven from a belt 17 in turn powered by a pulley 18 mounted on the end of shaft 19' of an electric motor 28. The motor, pulleys, and roller 13 are so proportioned to the drum and to each other that drum 2 is rotated by roller 13 at an appropriate relatively low speed to provide tumbling action for articles of clothing placed therein. With the driving arrangement described, the driving roller 13 provides the entire support for the rear end of drum 2 so that the force with which the drum presses down on it is a direct reflection of the weight of the clothes in the basket.

In order that a stream of drying air may be introduced and passed through the clothes drum, the drum is provided with a central aperture 21 in its front wall 8 and with a plurality of perforations 22 extending in an annulus around its back wall 7. Rigidly secured to the rear wall 23 of cabinet 3 by any desired means such as, for instance, welding at suitable points 24, is a baffle-shaped member '25- which has secured thereto heating elements 26 appropriately insulated from the battle member. Heating elements 26 may be annular in shape so as to be generally coextensive with perforations 22 and drum. 2. A second bafile member 27 is rigidly secured to the back wall 7 of the drum outside the ring of perforations 22 and within the stationary baffle 25 so that an annular air inlet 23 is in effect formed by the two baflles 25 and 27. Baffle 27 is further provided with an annular series of openings 29. In this manner, the baffles form inlet duct means, and a passage is provided for air to enter annular inlet 28 between the baffles, pass over the heating elements 26 thereby to be warmed, through openings 29, and then through perforations 22 into the interior of drum member 2.

In order to secure drum 2 so that it is supported by the roller members and 13 without any undue horizontal motion but with a reasonably limited and permissible amount of vertical motion, a suitable thrust bearing arrangement, such as that generally indicated at 2911, is provided in baflle member 25 to receive a stub shaft 2% secured to baffle member 27. The bearing arrangement 29a permits the entire weight of the drum 2 and its contents to be taken up by the roller member while at the same time preventing any tendency toward displacement of the drum in any horizontal direction. The construction including bearing arrangement 29a is described in full detail and is claimed in application Serial No. 789,- 869, filed January 29, 1959, now Patent No. 3,009,259 by William L. Simpson and assigned to General Electric Company, assignee of the present invention.

The front opening 21 of the drum is substantially closed by means of a stationary bulkhead generally indicated by the numeral 30. Bulkhead 30 is made up of a number of adjacent members including the inner surface 31 of an access door 32 mounted on the dryer cabinet, a stationary frame 33 for the door, the inner surface 34 of an exhaust duct 35 leading from the drum, and an annular flange 36 mounted on the frame 33 and the duct wall. It will be noted that a suitable clearance is provided between the inner edge of the drum: opening 21 and the edge of bulkhead 30 so that there is no rubbing between the drum and the bulkhead during rotation of the drum. In order to prevent any substantial air leakage through opening 3 1 between the interior and the exterior of the drum a suitable ring seal 37, preferably formed of feltlike material, is secured to flange 36 in sealing relationship with the exterior surface of drum wall 8.

Front opening 21 serves both as part of the airflow path through the drum and as a means whereby clothes may be loaded into and unloaded from the tub. The door 32, whose inner surface forms part of the bulkhead 36 closing the opening 21, is mounted on cabinet 3 and when the door is opened the clothes may be inserted into or removed from the drum through the door frame 33. It will be noted that the door includes an outer imperforate section 38 and an inwardly extending hollow section 39 mounted on the flat outer section. Hollow section 39 extends into the door frame 33 when the door is closed, and the door surface 31 which comprises a part of the combination bulkhead 30 is actually the inner wall of this hollow section. The air outlet from the basket is provided by a perforated opening 40 formed in the inner wall 31 of hollow door section 39. The bottom wall of the door section 39 and the adjacent wall of door frame 33 are provided with aligned openings 41 and 42, with opening 42 providing the air entrance to duct 35'.

Duct 35 leads to a lint consuming assembly 43 of the type which is fully described and claimed in the aforementioned copending Sasnett application. As described in detail in that application, the lint is consumed within the lint consumer by means of a high-voltage spark provided by the use of a step-up transformer connected across the line. From the lint consumer 43, the air flow passes through a centrifugal blower 44 which is mounted on the motor shaft and thus driven by motor 20. Blower 44 is formed in the conventional manner (not shown) to connect through an exhaust duct with an outlet from the cabinet 3.

It will be manifest that when the motor 20 is not rotating at a speed suitable to cause blower 44 to move air through the basket and out through the exhaust duct and the lint consumer at an appropriate rate, it will not be desired to have the lint consumer operating since this may present a fire hazard. In order to effect this goal, I provide my improved control arrangement as shown in FIGURE 2.

Referring now to that figure, there is shown an electrical arrangement whereby three supply conductors 45, 46, and 47 are provided, conductor 46 being a neutral conductor so that a voltage of 220 volts is carried between the two conductors 45 and 47, and a voltage of volts appears between conductor 46 and each of the conductors 45 and 47. A conventional sequence controller mechanism, indicated at 48, is provided so as to be operated in the usual way by the 110 volt supply appearing across conductors 46 and 47. Among its other functions, the controller 48 controls the operation of the heater elements 26 so as to energize them across the 220 volt supply, that is, between conductors 45 and 47, for appro priate periods during the operation of the machine.

In order to control the energization of the motor 20 and of the ignition transformer, indicated by the numeral 49, the sequence controller including a contact 50 which, when in its up position, as shown, disconnects condoctors 51 and 52 so as to remove all power from the motor and the transformer, and in its down "position completes the connection between conductors 51 and 52. This completed connection, as will be described, is effective to permit power to be supplied to the motor and ignition transformer.

iFrorn conductor 52 an energizing circuit for the main winding 53 of the motor may be provided through conductor 54, the main winding itself, and conductor 55 which may, as shown, include a suitable conventional motor protector 56. Conductor 55 connects with neutral 46; in this manner, when contact 50 connects conductors 51 and 52 an energizing circuit for the main motor winding 53 is completed from conductor 47 back to conductor 46.

The motor is provided with a speed-responsive switch 57, generally of the centrifugal type. Switch 57 is in the position shown engaging contacts '58 and 58a when the rotor of the motor, schematically shown at 59, is at rest or rotating below a predetermined speed; as a result of the action of the centrifugal mechanism 60, at the predetermined speed and thereabove switch 57 is caused It will be understood that the induction motor 20 is' of the conventional type wherein its windings 53 and 61 have relatively low, ,impedances.

Transformer 49 is of the step-up type having a primary winding 63 with, a relatively small number of turns of wire and a secondary winding 64 having a relatively high number of turns of wire, both windings being wound on a magnetic core member 65 which is formed in a suitable manner so as to cause the transformer 49 to be of the conventional relatively high-impedance type. One end of the primary winding is connected to contact 58, and the other end is connected to a point 66. The secondary winding 64 has terminals 67 and 68 connected respectively to its ends, the terminals being so positioned that, when a high voltage is induced in winding 64 by power impressed across winding 63, a spark passes be tween them.

With this structure, the motor windings 53 and 61 each have a first end which is connected to the source of supply through conductor 55, and the transformer primary winding 63 is connected across the other ends of the motor windings. It will be observed that below the predetermined speed switch 57 connects the other end of winding 61 to conductor 52 and, thus, to the other side of the source of power; also, the other end of the main motor Winding 53 is connected to the other side of the main source of power through conductor 54.

During operation of the dryer, as initiated by means of a suitable manual control member 69 (FIGURE 1), the controller provides for energization of the heaters 26 at suitable times. Also, the controller lowers the contact 50 for the duration of the operation thereby connecting conductors 51 and 52 together. With this arrangement an energizing circuit is completed for both the main winding 53 and the start winding 61 of the motor as previously described. Also, with the switch 57 in the position shown, a closed or short circuit for transformer primary winding 63 is provided since the switch 57 serves to connect one end of the primary winding through conductor 54 directly to the other end thereof. Thus, even though the motor is energized, as long as it is not rotating at the predetermined speed no spark can be provided by the transformer 49.

An energizing circuit is completed through the switch 57 and conductor 62 for the start winding 61 as previously described. With this enengization of the two motor windings, the motor starts to rotate, and as it comes up to speed the switch '57 opens. Upon opening of the switch 57, there is no longer a short circuit provided across the transformer primary winding 63. Instead, a circuit is provided which, starting at conductor 55, extends through start winding 61, conductor 62, primary winding 63, and conductor 54 to conductor 52. Because the trans-former 49 is a relatively high-impedance low-current device, the current passing through the start winding 61 is so low as to have no adverse eflect on the start-winding even though the start winding may be formed in the conven tional manner, that is, not designed to be operated at normal motor current during operation of the motor. The primary winding 63 thus receives line voltage and causes a spark to pass between terminals 67 and 68 of secondary winding 64. In addition to theline voltage, it will be recognized that induction motors invariably produce the phenomenon of an induced voltage in the winding 61 as a result of the rotation of rotor 59, and thus the voltage across the terminals of primary winding 63 is the vectorial sum of the line voltage and the induced voltage from winding 61.

Termination of a drying operation by raising contact 6 50to disconnect conductors 51and SZ'de-energizes the motor 20 so that the speed returns to zero, thereby causing closing of switch 57 and again short circuiting the primary winding 63 of the transformer. It will be recognized that should the motor fail to provide the desired rate of rotation for any reason other than non-energization, the speed-responsive contact arm 57 will return into engagement with contacts 58 and 58a; thus, in that case also, the primary winding 63 will be short circuited and no spark will be provided across terminals 68 and 69. In this manner, not only the energization but also the rate of rotation of the motor 20 is used to control the provision of a spark in the lint consumer 43. This is effected, as shown, without the use of any additional switches, or even of any additional contacts such as those frequently provided in starting switch mechanisms.

Referring now to FIGURE 3 there is shown a fragmentary schematic view in which parts not shown or only partly shown are identical to those of FIGURE 2, and in which parts which are shown and are the same as those of FIGURE 2 are represented by like numerals. In this case, instead of conductor 52 being directly connected to the speed-responsive svw'tch arm 57 it connects with 'a conductor 70 whose completion is dependent upon depression of a manually operated switch 71. Switch 71' is biased ot open position by a spring 72 so that except when manually depressed the switch is open. In addition, the circuit includes a conductor 73 which also joins the conductor '52 and terminates in a contact 74 connected by switch arm 57 to contact 74a when it is moved to open position, that is, away from contacts 58 and 58a, as a result of the rotation of rotor '59 at or above the predetermined speed.

In order to start the motor, the switch 71 is manually depressed and this provides the same circuit as previously described for causing energization of the motor. As the motor comes up to speed the contact arm 57 moves over into engagement with contacts 74 and 74a thereby bypassing the switch 71 (which returns to open position when released) and completing the energizing circuit for run'winding 53 through conductor 73. This particular type of circuit is more fully described and claimed in Patent No. 2,858,619, issued on November 4, 1958 to Philip G. Hughes and assigned tothe same assignee as the present application. This type of circuitry is provided, as fully described in the Hughes patent, for purposes of safety, preventing energization and running of the'motor 20 except in response to a specific manual operation. The Hughes type of circuit is shown with my invention incorporated therein to demonstrate a second type of motor circuitry which may incorporate the modifications needed to carry out my invention.

While in accordance with the patent statutes I have shown what at present are considered to be the preferred embodiments of my invention, it will be obvious to those skilled in the art that various changes and modifications may be made without departing from the invention, and I therefore aim to cover in the appended claim all such equivalent variations 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:

A clothes dryer comprising: a clothes container; blower means for providing a draft of air through said container; an induction-type motor connected to said clothes container and to said blower means so as to rotate said clothes container at tumbling speed and said blower means at a speed appropriate to move air through said container; exhaust duct means for the air connected to said container; low energy means for consuming lint carried from the clothes into said exhaust duct means including a relatively high-impedance step-up transformer having a primary winding with a relatively small number of turns and a secondary winding with a relatively high number of turns, and spaced terminals at the ends of said secondary winding, said transformer providing a potential drop between said terminals sufliciently high to cause passage of a spark between said terminals to consume lint when said primary winding is energized; and a pair of supply conductors; said motor having relatively low-impedance main and start windings each having one end connected to one said supply conductor, said main winding having its other end connected to the other of said supply conductors, speed-responsive switch means connected to said other end of said start Winding, said switch means being connected to the other end of said start winding up to a predetermined rotational speed of said motor and being disconnected therefrom above said predetermined speed,

a: said transformer primary winding being connected between said other end of said main winding and said other end of said start winding. 1

References Cited in the file of this patent UNITED STATES PATENTS 2,180,580 Clark Nov. 21, 1939 2,549,265 Trant Apr. 17, 1951 2,819,540 Toma et al. Jan. 14, 1958 2,863,224 Zehrbach Dec. 9, 1958 2,882,610 Hughes Apr. 21, 1959 2,925,664 Cobb et a1. 'Feb. 23, 1960

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