US 2707837 A
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Description (OCR text may contain errors)
y 0, 1955 J. H. ROBINSON ETAL CLOTHES DRIER 4 Sheets-Sheet l V Ihven'b91'-s John HRobmson;
Their Abb ofneg Paul L. Paulsen,
Filed Feb. 3, 1951 May 10, 1955 J. H. ROBINSON EIAL CLOTHES DRIER 4 SheetsSheet 2 Filed Feb. 3, 1951 lnvefio or-s JohnH Robin '1 Paul L. Paulsen y 0 5 J. H. ROBINSON arm. 2,707,837
CLOTHES DRIER Filed Feb. 3, 1951 4 Sheets-Sheet 3 Inventors: John H. Ribiwsofl'. Paul L. au sen, aflA/kL/W TheirAbtomey.
May 10, 1955 J. H. ROBINSON El'AL CLOTHES DRIER 4 Sheets-Sheet 4 Filed Feb. 3, 1951 Inventqvs U John H. Robu son;
Paul L. Paulsen Their Attorney.
United States Patent CLOTHES DRIER John H. Robinson, Stepney Depot, and Paul L. Paulsen,
Bridgeport, Conn., assignors to General Electric Company, a corporation of New York Application February 3, 1951, Serial No. 209,280
11 Claims. (Cl. 34-133) Our invention relates to a clothes drier of the tumbler type, and in particular to a drier adapted for domestic use.
We have directed our invention primarily to the objective of providing a clothes drier having a simplified construction capable of efficient performance over a long life span, arranged for easy servicing by mechanically unskilled persons, and embodying improved safeguards against overheating and accident to the operator.
More specifically the objects of our invention include the provision of an air distribution system which improves heat transfer by force convection and conduction and minimizes the accumulation of lint in diflicultly accessible areas within the drier; lint trapping and disposal means arranged for conversion of the drier from a conventional front exhaust type to one in which the lint laden air is conducted through a rear duct which may be piped through the building wall or floor for discharge remote from the room in which the drier is located; a simplified heater chamber construction which provides a tumbler shaft supporting structure of substantial rigidity; and an improved electrical control and heating circuit embodying safety interlocks to insure against the operation of the drying tumbler when the door is open or the energization of the electrical heating means in the event that the drive motor fails to attain rated speed.
In a presently preferred embodiment of our invention we mount a foraminated tumbler within a heated, insulated, chamber for rotation on a non-vertical axis. At a lower corner of the chamber there is provided an air duct extending the full length thereof; by suitable fan means we develop within the duct an air pressure somewhat above that of the chamber atmosphere. This air is sub stantially at room temperature and discharges into the heater chamber as sheets or curtains of air, one of which flows about the tumbler counter to the direction of rotation thereof, while another conforms generally to the direction of rotation, impinging angularly against the bottom of the tumbler.
We have found that it is unnecessary and wasteful of heat and power to follow contemporary practices which seek to force air through the tumbler and the clothes load thereof; nor do we attempt to induce air flow through the tumbler by the ejector action of a powerful air stream discharging from a constricted throat. In our air distribution system as above described, the air curtains serve largely as a vehicle for the humid air which is discharged through the interstices of the tumbler by the mechanical action of the clothes being tumbled therein. Thefirst-named air curtain abstracts heat from heating means within the chamber; transfer of heat from the air to the tumbler is improved by the turbulence caused by the counter-rotation of the tumbler relative to the air stream. The air discharging against the tumbler wall mixes with the humid air being forced through the tumbler walls and dilutes it to reduce its temperature, and to some extent, its humidity. This is particularly advantageous in the front discharge drier, which exhausts directly into the room in which the drier is placed. The respective air curtains follow mutually divergent paths, and there is created a zone of relatively quiet air beneath the tumbler immediately above the air duct. Lint falling from the tumbler will settle on the roof of the air duct. We have arranged the tumbler relation to said roof so that the tumbler sets up air currents which sweep the lint from the roof into the path of the second air stream by which it is transported to the lint trap.
In the control circuit we provide an interlock switch which interrupts the drive motor power when the door is opened thus reducing the possibility of accident to the user and we also make heater energization dependent upon the attainment of the normal running speed of the drive motor. Thus, the heaters will not operate in the event that overloading the tumbler or unusual mechanical deficiency causes the motor to stop or to run at less than rated speed. This is desirable because at speeds too low to produce proper tumbling and air flow the clothes should not be heated. This system plus a conventional thermostat switch safeguard which interrupts the heater circuit should the air-temperature within the casing rise above a predetermined point protects against the scorching of the clothes load or the combustion of lint which may have accumulated Within the chamber.
Other features and advantages of our invention will be better understood from the following detailed description of the presently preferred embodiment as illustrated in the accompanying drawings, in which Fig. 1 is a front elevation of one form of drier embodying our invention, certain casing portions having been broken away to reveal underlying structure; Fig. 2 is a section taken on lines 2-2 of Fig. 1 and showing a suitable door hinge and a circuit interlock switch operated by door action; Fig. 3 is a side sectional elevation of the drier of Fig. 1 on line 3-3 of Fig. 1; Fig. 4 is a sectional elevation taken through the lint trap of the Fig. 1 embodiment; Fig. 5 is a corner construction detail showing a method of insulation securement and application of the top wall portion of the outer housing; Fig. 6 is a rear elevation of the drier, cer tain portions being broken away; Fig. 7 is a detail in sectional elevation showing a method of constructing the heater chamber and securing the insulation thereto; Fig. 8 is an end elevation detail of a method of mounting the heating elements; Fig. 9 is a plan section taken just above the lint drawer of a second embodiment showing the association with said drawer of a rear discharge duct; Fig. 10 is a side sectional elevation of the lint drawer construction of Fig. 9; and Fig. 11 is a typical wiring diagram.
Referring to the drawings, the general structure of a drier embodying our invention comprises an outer housing 1 having conventional unitary wall panels arranged in wrap-around fashion on a suitably reinforced foot provided base 2. The rear panel 3 is attached to side wall flanges and to the base 2 by removable fastenings to provide for easy access to the drive mechanism, later described. A cylindrical sleeve 4 extends inwardly from the rectangular recessed front housing wall portion 5 within which a door 6 seats when closed. The door is preferably gasketed by a resilient strip 7 which compresses against the front wall panel when the door is latched in closed position by conventional means (not shown). The gasket prevents the escape of lint duringthe operation of the drier. We prefer to hinge the door by concealed hinges 8 as shown in Fig. 2. As usual, the door may have a transparent window 9 through which the interior ofthe drier is visible. The front panel overhangs the base as shown best in Fig. 4 to provide toe space, and the lower front casing portion therefore conveniently comprises an angle strip 10, hereinafter called a toe-board panel, to the projecting portion of which the bottom edge of the front casing wall is fastened.
Integration of the five sides of the housing above the base is accomplished in a manner which provides a simple, rigid assembly. As presently constituted, the upper edge portions of the front and side walls of the housing are inwardly flanged to support the similarly flanged front and side edges of the top panel 11. Tab-like extensions 12 of the top panel front flange act as catches for engagement with the flange of the front wall, see Fig. 5, whereas tabs 13 of the side flanges serve as side wall guides as shown in Fig. 1. The rear wall 14 of the top panel extends below the upper edge of the side panels and consequently the rear edge flanges 15 thereof terminate equivalently below the top edges of the panels so that said rear wall 14 is in abutting relation therewith. The rear panel 3 overlies the side wall flanges 15 and the rear wall 1.4 and is secured thereto, as shown by Fig. 6.
The heater chamber itself is carried entirely by the base 2. For the cylindrical tumbler type of drier presently exemplifying our invention, we employ eccentrically horseshoe shaped front and rear panels 16, 17, flanged at their lower ends to be fastened to the base wall structure 2 as seen in Fig. 3. Each panel is appropriately apertured to accommodate various operating components; for example, the forward wall 16 has a projecting flangedended cylindrical aperture 18 which secures to the front outer casing panel about the sleeve 4, with respect to which the aperture is concentric. We prefer to gasket the connections between the respective front and rear panels of the heater casing and the outer casing. About the front and rear panels, 16, 17, we wrap a metal sheet 19, the forward and rear edges of which are flanged to overlap the peripheries of said panels in a socket-like arrangement shown best in Fig. 5. Such arrangement makes it unnecessary mechanically to secure the sheet 1) to the front and rear panels. A convenient manner of affixing the sheet 1? to the base 2 is shown in Fig. 7. The lower side edges 20 of the sheet are shaped to provide a resilient bead which rests upon a base wall portion 21 ofl'set to the required angularity. Machine screws 22 passing through aligned apertures in the beads 20 into tapped holes in base wall 21 draw the sheet 1% securely into position. The resilience of the beads 29 affords a yieldability which compensates for minor irregularities of alignment; the reaction of the beads also provides a locknut effect which holds the screws 22 against unloosening. We insulate the heater chamber with conventional materials such as glass wool pads or batts. The insulation adjacent sheet 19 is conveniently held in place by straps 24 which are clamped against the respective base ofl'sets 21 by the beads 20 and screws 22. Front and rear wall insulation is held in place by tabs 25 extending variously from sheet 19 over the front and rear panels 16, 17.
Heater 26 is an integrated assembly, as best shown by Figs. 6 and 8, preferably embodying a channel-like frame 27 from which projects a suitable number of insulators 28 on which the resistance wire 39 is convoluted over an area which extends substantially the whole length of the heater chamber. A reflecting sheet 31 is fixed back of the heater coil and we guard against direct contact of lint with the coils by providing a guard screen 32, the mesh of which is sufliciently large to pass radiant heat in substantial quantity. The heater assembly is passed through an opening 33 in panel 17 and is supported on channels 34. The channels are secured to said panel and to front panel 16 by screws engaging the several brackets 34.1. At the rear panel 17 the insulation is suitably arranged to provide a space for a binding post plate 35 which insulatedly carries the heater coil connection terminals 36.
Panel 17 is set sufiiciently forward of outer housing panel 3 to provide a relatively deep rear compartment which accommodates the tumbler drive mechanism and serves as an air admission chamber communicating by way of the louvres 38 with the outer atmosphere. Tumbler 40, which illustratively is of the horizontal axis cylindrical type, has imperforate front and rear walls 41, 42
4 and a foraminated peripheral wall 43. The front wall has a short neck 44 which extends in concentric overlapping relationship with the collar 4.
It will be noted that tumbler is supported only at its rear end. Accordingly, we impart rigidity by inwardly dishing a relatively large central area 47 of rear wall 42 and secure the center of said wall portion by rivets or the like to the flanged end of an enlarged head portion of tumbler shaft 45. We also provide a dished reinforcement plate 46 riveted to rear wall 42 and secured to the drive shaft in spaced relation with respect to said wall 42. A plurality of conventional triangular tumbling ribs 48 provide tumbling and flutfing" the clothes as the cylinder is rotated. The tumbler support structure comprises a rigid relatively wide channel 50 bolted through base 2 to a heavy plate 51 (see Fig. 6) and preferably riveted through its web to heater chamber panel 17. A stiffening angle member 52 is affixed to the upper end of channel 50 as shown in Fig. 6 and extends transversely across the rear panel 17 to which it also is secured. The ends of the angle member 52 extend to, or slightly beyond the marginal edges of the heater chamber side wall panel. Thus, the forward thrust of the channel 50 occasioned by the weight of the tumbler and its contents is opposed by the very substantial resistance to distortion of the heater chamber which acts as a large box girder firmly affixed to the base 2.
The shaft and tumbler supporting means comprises a relatively heavy sleeve 53 which rests within a centering notch 54 provided in the upper end of channel 50 and within the similarly notched rear wall 55 of a bracket 56 fixed to the side flanges of the channel and projecting rearwardly therefrom. The web of the channel and the said rear wall 55 provide relatively widely spaced support points. A saddle clamp 57 secures the sleeve in position. Within the sleeve we provide suitable bearings 58, 60, preferably of the oil impregnated type, within which shaft 45 rotates.
Drive motor 61 may be mounted on base 2 with a conventional resilient bearing cradle as shown. Reduction from the 1725 R. P. M. motor speed to the 50 R. P. M. tumbler speed may conveniently be accomplished by belt drive through an idler sheave system in which the idler 62 is belt connected to drive sheave 63 on the motor shaft and is in turn connected through its associated sheave 64 to sheave 65 fixed to shaft 45. For maintenance of belt tension we support sheave 62 on an idler bar 66 passing through openings of suitable dimension in angle member 52 and a second angle member 67 secured to rear panel 17 below the level of shaft 45 and at one side of channel 50, as clearly appears in Fig. 6. The openings are sized relative to bar 66 and aligned with respect to each other in such fashion that under the bias of the spring 68 the bar is urged downwardly and to the left of Fig. 6 and has a limited freedom of lateral plane rotation relative to the respective sheaves. Such single unit belt tensioners are well known in the art and we make no claim thereto.
The air distribution system includes a plenum or pressure chamber from which air flows into the heater chamber, and a lint trap through which it is exhausted. The plenum chamber (see Fig. 1) comprises the base 2 and lower portion of the heater chamber side wall sheet 19 in association with a side wall plate 70 and a roof plate 71, each of the latter plates extending the full length of the heater chamber for securement to the end wall panels thereof. As appears in Figs. 3 and 6, the motor 61 is mounted in the plenum chamber and its shaft carries the fan 72 which operates in the plane of an opening 73 formed in the rear wall panel 17. The fan draws air through louvres 38 into the plenum chamber from which it discharges under pressure through two relatively narrow slots 74, 75, which are substantially parallel to the tumbler axis. Each air discharge is sheet like. Slot 74 directs air upwardly to follow the side Wall sheet 19 of the heater chamber in a direction counter to the rotation of a tumbler whereas the air discharging from 75 impinges against the bottom of the tumbler in the direction of tumbler rotation. These air slots are conveniently formed by spacing the edges of the plate 71 with respect to the side wall plate 70 and the side wall sheet 19, and, therefore, extend the full width of the heater chamber. The upwardly traveling air sheet or curtain envelopes the heater unit 26 and abstracts heat therefrom and incidentally serves to cool the side wall and roof portions of the heater chamber reducing the insulation requirements thereof. In the domestic type clothes drier exemplified herein, the heater coil is rated at approximately 4400 watts. The metal channellike housing for the coils absorbs a substantial amount of heat which is transferred to the air flowing thereabout. The turbulence created by the relatively rough peripheral wall of the tumbler improves heat transfer from the air to the tumbler wall and the pump-like effect of the motion of the clothes within the tumbler produces an interchange of the external heated air and the humid air volume which builds up within the tumbler. The tumbler and contents also benefit by the substantial amount of radiant heat of the heat coils reflected toward the tumbler by the reflector plate 31.
As is well known, laundry which is taken from a domestic washing machine after having been damp-dried by centrifuging or run through a wringer has a moisture content which may be equal to or more than the dry weight of the clothes according to the efliciency of the damp-drying devices. Assuming a conventional nine pound washer load, it is apparent that the clothes when placed in the tumbler may contain at least nine pounds of water, of which, assuming that the purpose of the drier operation is to leave the clothes sufficiently damp for immediate ironing, about 80% is to be extracted. The air discharging through the tumbler wall is therefore very humid during the first portion of the cycle. The air becomes increasingly less humid, and hotter, as the drying operation proceeds, and ordinarily contains a substantial amount of lint which is shaken from the articles of laundry during the tumbling thereof. The air stream discharging through 'slot 75, being cool and flowing about the lower left quadrant of the tumbler as viewed in Fig. 6, reduces the temperature of the air discharging from the tumbler. During the later portion of the drying operation, such a temperature reduction is very desirable, particularly when the drier discharges into the room in which it is located.
The discharge from the heater chamber is through a lint trapping device of which different embodiments are shown respectively in Figs. 4 and 9. The Fig. 4 embodiment exhausts through the toe-board panel which is provided with a relatively long eccentrically disposed opening snugly to receive the trap, which as best appears in Figs. 3 and 4 is a drawer-like structure having a base panel 76 from which sides 77 extend upwardly, and an upwardly-sloping mouth structure 78 A convenient method of affixing the mouth structure to the side walls is by welding flanges 80, struck outwardly from the sides of the mouth, to similar flanges projecting from the side walls 77. The flanges come to rest against the front of the toe board when the lint trap is in home position. We provide a lint trap screen 82 suitably arranged in a frame 83 for securement to side wall brackets 84, and bend the rear edge 85 of the bottom wall 76 about the transversely extending screen frame member as shown in Fig. 4. Thefront edge of the screen frame is carried forwardly of thetoe board and is bent upwardly to lie snuglythereagainst when the lint trap is in position. Additional guidemeans-for positioning the lint trap may include side flanges 87 formedin the front heater chamber wall 16. It is intended that the user periodically remove the lint trap to brush or otherwise clean the ac- 6 cumulation of lint on the screen. However, in considera-v tion of the possibility that this may not be done we pre vide a port 88 in the respective walls 77 so as to insure the discharge of air from the heater chamber even in the circumstance that the lint trap screen is substantially blocked by a lint accumulation.
In the second form of lint trap shown in Figs. 9 and 10 we also provide a drawer-like structure 90 having a front panel 91 which serves completely to cover the opening in the toe board with a substantial marginal overlap. To guard against the escape of lint from between the panel 91 and the toe board the cover is provided with a suitable gasket 92. Spring clips 93 latch against the edges of the toe board 10 to hold the lint drawer in position. As best appears in Figs. 9 and 10 the lint drawer includes a base 94 from which the side walls 95 are struck upwardly and a screen 96 which occupies substantially the full length of the drawer and the full width thereof. The screen may be framed as in the Fig. 4 embodiment and held in position with suitable tabs or flanges as shown. The screen slopes upwardly from the front to the rear of the drawer and provides a barrier through which all of the lint laden air must pass in transit from the heater chamber. The rear heater chamber panel 17 is provided with an opening over which a cover plate 97 is removably applied. It will be observed from a comparison of Figs. 1 and 6 that the opening in panel 17 is of substantially less width than the opening in the toe board 10 necessary to accommodate the lint drawer. The purpose of this is to utilize conventional air duct sizes, for example, approximately 3 /2 in. deep by 10 in. wide in the ductwork for the rear discharge trap arrangement. The rear edge walls of the drawer fit snugly against the panel 17. The rear casing panel 3 has an opening provided with a removable cover plate 98, said opening and cover plate being slightly larger than the opening and cover plate 97 of the panel 17 as best appears in Fig. 6. When a rear discharge system is to be utilized the respective cover plates 97 and 98 are removed and a duct section 99 suflicient to extend suitably beyond the rear casing 3 is inserted through the rear casing opening and is secured to the chamber wall 17 by screws or equivalent passing through the inwardly directed flanges of the extension. The size of the duct extension is such that the mechanic may easily reach through it to complete the fastening. Further duct extensions may be aflixed by conventional slip fit elements, not shown.
In all tumbler driers of which we have knowledge, some lint will accumulate within the heater chamber; not all of the lint remains suspended in the air stream discharging through the lint trap. We appreciate that this will also be true in a drier constructed according to our invention as above described. However, we effectively minimize the accumulation of lint in diflicultly accessible portions of the chamber by the relationship of the plenum chamber and the direction of air discharged therefrom to the tumbler and its direction of rotation, as well as by the horseshoe slope of the casing defined by the wall panels 16 and 17 and the enclosing sheet 19, which shape makes it possible to avoid having narrow lint trapping passages between the casing and the lower portion of the tumbler 40. The disposition of the air slots 74 and 75 creates a small quiet air zone immediately above and in the right of the plenum chamber roof panel 71 as viewed in Fig. 1. The air curtain from slot 74 follows up along the wall 19 until loss of momentum causes it to difluse around the heater assembly, and the force of discharge through slot 75 reduces turbulence which might produce back-flow over the panel 71. The slope of roof panel 71 toward the tumbler and the direction of rotation of the tumbler establishes a condition in which the tumbler acts as an air-pump which produces a relatively gentle air flow through the throat 100 formed by the convergence of the tumbler and the roof panel 71. The diffusing curtain from slot 74 maintains a sufficient turbulence about the upper portion of the tumbler and the heating unit to preclude lint from settling thereon. Lint which may be carried through the lower portion of the tumbler by the mechanical action of the clothes movement therein will be mechanically transported into the qiuet zone area where some of it will deposit on the roof panel 71. Eventually the air movement induced by the tumbler sweeps the lint into the air flow discharging from and it will be carried by said air flow toward the lint trap. The air discharge from orifice 75 sweeps the bottom portion of the tumbler and removes lint which may have adhered thereto. The air movement through the orifices 74 and 75 provides a discharge pattern which minimizes lint accumulation in ditficultly accessible portions of the heater chamber. Accordingly, the chamber may easily be cleaned with conventional vacuum cleaner accessory tools.
In the wiring diagram, Fig. 11, the several control and safety devices are well known in the art and have been somewhat schematically shown. Timer 102 is of the 2- pole type in which cams or equivalent 103, 104 are fixed to a common shaft driven by a conventional timer motor 105; a knob 106 provides on-otf control and for the selection of any desired drying period. Thermostat 107, illustratively of the well known bulb and capillary tube type, is provided with conventional temperature adjustment means (not shown) by means of which the air temperature within the heater chamber may be held within reasonable limits. As best shown in Fig. 3, we placed the temperature sensitive bulb 1.08 suitably within the heater chamber to sense an average temperature therein. The location shown in Fig. 3 may not actually be that selected for the bulb; some experimentation may be required to determine the most advantageous standardization of bulb location. It will be understood that the thermostat is the type which closes its circuit when the bulb temperature is below the setting point. For protection against thermostat failure of other unusual condition which might cause heater chamber temperature to build up dangerously, we employ a non-adjustable limit control 110 for which the concave bi-metal snap switch type well known in the art is satisfactory. Drive motor 61 will have the conventional centrifugal start switch 111, current inrush type relay, or other device which transfers from a starting position to a running position, as is well understood. A double throw switch 112 spring biased normally to one throw position is mounted in the front casing panel to be operated to its other throw position by the engagement of the drier door 6 with the switch operating plunger 113 as the drier door is closed; see Fig. 2. We employ a conventional plug fuse 114. To facilitate fuse replacement we place the fuse receptacle 115 (Fig. 3) on the projecting wall of the toe board 10 so that the receptacle will be behind the front casing panel. The head of the fuse (not shown) will be accessible beneath the toe board ledge. We conceal the fuse head behind a swing able cap 116 pivotally affixed to the toe board ledge and secured by a thumb nut 117, see Fig. I. It will be understood that the rear of cap 116 is open and that when the cap is on home position, the rear wall of the toe board completes the fuse head enclosure. For illumination of the interior of the heater chamber and the tumbler, we provide an incandescent lamp 118 socketed within the plenum chamber behind a removable window 120. An ozone producing lamp 121 similarly within the plenum chamber tends to give the air within the chamber a fresh outdoor odor which is to some extent imparted to the clothes.
We utilize a conventional three-wire 230 volt circuit as appears in Fig. 11. When the operator opens door 6 to load the tumbler, switch 112 will close its contacts 112a and the lamps 118 and 121 will receive power through the obvious circuit. After the tumbler is loaded, closing the door 6 will operate switch 112 to close its contacts 112b establishing one portion of the motor circuit, but not yet completing said circuit. The lamps will 8 extinguish. The operator then turns knob 106 to rotate cams 103, 104, counterclockwise of Fig. 11. The respective cam control switches 103a, 104a will close simultaneously. Lamps 118, 121 will relight through a circuit comprising a power conductor 122, switch 103a and a neutral conductor 123. Drive motor 61 will energize through a circuit including conductor 122, switch 103a, conductors 124, 125, start switch 111, a start winding conductor 126, switch 112b (now closed), a conductor 127, fuse 114 and neutral 123. The run winding will also be energized through the obvious circuit. Timer motor 105 will operate through conductors 128, 129, 126 and switch 11211 to neutral. It will be seen that should door 6 be opened after switch 102 had been operated to motor start position the immediate opening of switch 11% will stop the drive motor and the timer motor. Stopping the drive motor eliminates the possibility of accident resulting from reaching into or contacting a rotating tumbler.
The coils of heater unit 26 are connected into a 230 volt circuit when start switch is moved to its run position upon attainment of a normal motor operating speed. The heater circuit comprises a power conductor 130, switch 104a, a conductor 131, the normally closed thermally sensitive switches 107, 110, switch 111, conductor and conductor 124, switch 103a, and conductor 122. The drive motor, timer motor, and lamp circuit includes the conductor 122, switch 103a, conductor 124 and three branch parallel circuits from conductor 124 to neutral. The timer motor branch includes conductor 128, motor 105, conductor 129, switch contacts 112b, conductor 127, fuse 114, and neutral. The drive motor branch includes conductor 125, centrifugal switch 111, the run winding, the start winding (when the switch 111 is in the below rated speed position of Fig. 11), conductor 126, switch contacts 112]), conductor 127, fuse 114, and neutral. The lamp branch includes conductor 124 extended, lamps 118 and 121 and neutral. It is important to note that should the motor drop below running speed sufficiently for switch 111 to return to its start position, the heater coils are disconnected. The motor must be operating in the running speed range in order for the heaters to be energized and, therefore, the circulation of air through the heater chamber as well as the speed of rotation of the tumbler must be substantially at normal operating rate at all times when the heater coils are energized. Switch 104a is arranged to return to open circuit position a short while-for example, five minutes-before switch 103a opens. This provides a cool-down period in which the heater 26 is de-energized whereas the drive motor remains in operation to tumble the clothes and circulate the relatively cool air through the heater chamber.
While we have shown a particular embodiment of our invention, it will be understood, of course, that we do not wish to be limited thereto since many modifications may be made; and we therefore contemplate by the appended claims to cover any such modifications as fall within the true spirit and scope of our invention.
What we claim as new and desire to secure by Letters Patent of the United States is:
1. In a drier for fabrics and the like, a heater chamber, a substantially cylindrical, foraminated, tumbler mounted for rotation therein on a horizontal axis, means through which the tumbler may be loaded with articles to be dried, a plenum chamber disposed below the tumbler axis and adjacent the side wall of the heater chamber, said plenum chamber extending parallel to the axis of rotation of the tumbler and having a roof panel which slopes downwardly from said heater chamber wall toward the peripheral wall of the tumbler to form with said tumbler wall a tapering throat within said heater chamber, an elongated air discharge means between said roof panel and said heater chamber wall to discharge air away from said tumbler, a second elongated discharge means extending beneath said tumblerparallel to the axis thereof to discharge air toward said tumbler, heating means dis posed within said chamber above the tumbler remote from the first-named air discharge means, exhaust means communicating between said heater chamber and the outer atmosphere, means for rotating said tumbler, and means for creating within said heater chamber a pressure greater than that of the chamber atmosphere; the mutually divergent air discharges through said discharge means providing a relatively quiet air zone immediately above said sloping chamber roof within which lint dropping from said fabrics may fall to said roof to be brought through said throat into the path of air'discharging from said second discharge means by air currents induced by roration of said tumbler over said roof panel.
2. In a drier for fabrics and the like, a heater chamber, 21 substantially cylindrical tumbler mounted for rotation therein on an axis inclined from the vertical, wall portions of said tumbler being foraminated, means through which the tumbler may be loaded with articles to be dried, heater means within said chamber, an exhaust duct communicating between the heater chamber and the outer atmosphere, a plenum chamber disposed within said heater chamber displaced laterally from said exhaust duct and having a plurality of air discharge means into said heater chamber, means for rotating said tumbler to tumble the fabrics therein and thereby to enforce movement of air through the foraminations of said tumbler, and means for forcing air at normal room temperature into said plenum chamber to discharge into said heater chamber, means directing a portion of said discharging air about the tumbler and over said heater and a substantially equal portion of said discharging air toward said tumbler in the direction of said exhaust duct to dilute the heated air and thereby to reduce its temperature prior to the outflow thereof through said exhaust duct.
3. In a drier for fabrics and the like, a heater chamber,
- a substantially cylindrical, foraminated, tumbler mounted for rotation therein on a horizontal axis, means through which the tumbler may be loaded With articles to be dried, a plenum chamber disposed below the tumbler and adjacent the side wall of the heater chamber, said plenum chamber having a roof panel which slopes downwardly substantially tangentially toward the peripheral wall of the tumbler to form therewith a tapering throat within said heater chamber, an elongated air discharge means between said roof panel and said heater chamber wall to discharge upwardly along said wall to envelop a substantial portion of said tumbler, a second elongated discharge means extending beneath said tumbler parallel to the axis thereof to discharge air angularly against said tumbler in the general direction of rotation of said tumbler, heating means disposed within said chamber above the tumbler, exhaust means communicating between said heater chamber and the outer atmosphere, means for rotating said tumbler, and means for creating within said heater chamber a pressure greater than that of the chamber atmosphere whereby to discharge air through said discharge means.
4. In a drier for fabrics and the like, a heater chamber, a substantially cylindrical tumbler mounted for rotation therein on an axis inclined from the vertical, Wall portions of said tumbler being foraminated, means through which the tumbler may be loaded with articles to be dried, heater means within said chamber, an exhaust duct communicating between the heater chamber and the outer atmosphere, a plenum chamber disposed within said heater chamber laterally of said exhaust duct and of a vertical plane passing through the axis of rotation and having a plurality of air discharge means into said heater chamber, means for rotating said tumbler to tumble the fabrics therein and thereby to enforce movement of air through the foraminations of said tumbler, and means for forcing air from the atmosphere at normal room temperature into said plenum chamber, said plenum chamber air discharge means directing a portion of said 10 discharging air about said tumbler and said heater means to abstract heat therefrom and another portion of said discharging air away from said heater means and toward said drum in the direction of said exhaust duct to dilute the heated air and thereby to reduce its temperature prior to the outflow thereof through said exhaust duct.
5. A drier for fabrics and the like comprising a chamber, a substantially cylindrical tumbler arranged for rotation therein on a horizontal axis, means affording access to said tumbler for loading the same, an air duct disposed below said tumbler and laterally of the axis thereof, means for establishing a duct air pressure greater than that of the chamber atmosphere, means for discharging air parallel to the tumbler axis in mutually diverging curtain-like forms, one of said curtain-like discharges being counter to tumbler rotation and the other generally in the direction of rotation of said tumbler, said air duct having a roof member between said discharge means, said roof member sloping toward said tumbler and extending relatively close to the periphery thereof adjacent said second named air discharge means, means for heating the atmosphere within said chamber, exhaust duct means communicating between said chamber and the external atmosphere and a motor for driving said tumbler at a predetermined rate of speed.
6. A drier for fabrics and the like comprising a chamber, a tumbler arranged for rotation therein on an axis inclined from the vertical, means for introducing into said tumbler the articles to be dried, an air duct within said chamber, means for generating within said air duct a pressure greater than the chamber atmosphere, said air duct having a plurality of narrow, elongated, discharge orifices to direct air into said chamber in curtain-like form, the air discharging from one of said orifices being counter to the direction of rotation of said tumbler and the air discharging from another orifice being substantially in the direction of rotation, heater means disposed within said chamber in the path of discharge from the first named orifice, an exhaust duct displaced from said air duct and in said chamber in the path of discharge from said second named orifice, and motor means for rotating said tumbler.
7. A drier for fabrics and the like comprising a chamber, a substantially cylindrical tumblerarranged for rotation therein on an axis inclined from the horizontal, means affording access to said tumbler for loading the same, an air duct extending substantially the full length of said chamber, said air duct having a plurality of slotlike discharge orifices extending substantially parallel to the axis of the tumbler, means for establishing a pressure within said air duct and greater than the pressure of the chamber atmosphere whereby air will discharge from said orifices into said chamber and toward said tumbler in curtain-like form, one of said orifices being disposed relative to the tumbler to direct the discharge thereof counter to the rotation of the tumbler and another discharge orifice directing air flow toward the periphery of said tumbler and generally in the direction of rotation thereof, an exhaust duct displaced from said air duct communicating between said chamber and the outer atmosphere, and a motor for rotating said tumbler.
8. A drier for fabrics and the like comprising a chamber, a substantially cylindrical tumbler arranged for rotation therein on a horizontal axis, means affording access to said tumbler for loading the same, an air duct disposed within said chamber beneath said tumbler and displaced laterally of the axis thereof, said duct having a pair of slot-like discharge orifices extending parallel to said tumbler axis, means for establishing a pressure within said air duct greater than the chamber atmosphere whereby air will discharge from said orifices into said chamber in curtain-like form, one of said orifices discharging upwardly to follow the wall of said chamber and counter to the direction of tumbler rotation and the other discharging laterally toward said tumbler axis and 11 in the direction of tumbler rotation, an exhaust duct com inunicating between the chamber and the outer atmosphere and a motor for rotating said tumbler.
9. A drier for fabrics and the like comprising a chamber, a tumbler arranged for rotation therein, means for introducing into said tumbler the articles to be dried, an air duct within said chamber, means for generating within said air duct a pressure greater than the chamber atmosphere, said air duct having a plurality of narrow elongated discharge orifices to direct air into said chamber and toward said tumbler in curtain-like form, the air discharging from one of said orifices being counter to the direction of rotation of said tumbler and the air discharging from another of said orifices being substantially in the direction of rotation, heater means within said chamber remote from said air duct, an exhaust duct from said chamber adjacent one of said discharge orifices to receive air flow therefrom, and means for rotating said tumbler.
10. A drier for fabrics and the like comprising a chamber, a tumbler arranged for rotation therein, a heater within said chamber, means for introducing into said tumbler the articles to be dried, an air duct within said chamber, means for generating within said air duct a pressure greater than the chamber atmosphere, said air duct having a plurality of narrow elongated discharge orifices to direct air into said chamber in curtain-like form, the air discharging from one of said orifices being counter to the direction of rotation of said tumbler and toward said heater and the air discharging from another orifice being substantially in the direction of rotation, an exhaust passage from said chamber displaced laterally from said air duct, the entrance into said exhaust passage from said chamber being substantially directly adjacent said second named orifice to receive air discharge therefrom, and means for rotating said tumbler.
11. A drier for fabrics and the like comprising a chamber, a tumbler arranged for rotation therein on an axis inclined from the vertical, means for introducing into said chamber the articles to be dried, an air duct within said chamber, means for generating within said duct a pressure greater than the chamber atmosphere, said air duct having a plurality of narrow elongated discharge orifices to direct air into said chamber in curtain-like form, the air discharging from one of said discharge orifices being counter to the direction of rotation of said tumbler and the air discharging from another orifice being substantially in the direction of rotation, heater means disposed within said chamber in the path of air flow from one only of said discharge orifices, an exhaust duet displaced from said air duct in said chamber, means directing air from other of. said discharge orifices away from said heater, and motor means for rotating said tumbler.
References Cited in the file of this patent UNITED STATES PATENTS