US3790751A

US3790751A - Heater assembly for dryer

Info

Publication number: US3790751A
Application number: US00274646A
Authority: US
Inventors: L Kuhn
Original assignee: Maytag Corp
Current assignee: Maytag Corp
Priority date: 1972-07-24
Filing date: 1972-07-24
Publication date: 1974-02-05
Anticipated expiration: 1991-02-05
Also published as: CA986565A

Abstract

An electric heater assembly includes a housing comprising a pair of generally similar wall portions and further includes an elongated heating coil supported from the inside of said housing by a plurality of spaced and staggered insulating support members in a sinuous path extending transversely back and forth in a first plane and in a second plane. The coil is assembled to the respective wall portions while they are in an openly accessible side-by-side relationship. The wall portions are then closed like a clamshell to form the heater assembly with the coil supported on the interior surface thereof.

Description

United States Patent [191 Kuhn [451 Feb. 5, 1974 HEATER ASSEMBLY FOR DRYER [75] Inventor: L. Dean Kuhn, Newton, Iowa [73] Assignee: The Maytag Company, Newton,

Iowa

[22] Filed: July 24, 1972 [21] App]. No.2 274,646

[ 5 6] References Cited UNITED STATES PATENTS 3,111,571 11/1963 DeCamp 219/374 3,119,923 l/l964 Schlumbolm 219/375 1,971,387 8/1934 Scoville 219/525 1,492,821 5/1924 Weinbach 219/525 2,901,521 8/1959 Yoder et a1 13/25 3,548,159 12/1970 Ellstroem 219/535 2,834,867 5/1958 White 219/532 2,978,563 4/1961 Hackman 219/375 2,980,785 4/1961 Whitney, Jr. 219/374 X 3,050,867 8/1962 Friedman 34/133 X 3,192,359 6/1965 Swindall 219/523 X FOREIGN PATENTS OR APPLICATIONS 453,257 12/1927 Germany 219/525 721,657 12/1931 France 219/374 Primary ExaminerVolodymyr Y. Mayewsky Attorney, Agent, or Firm-William G. Landwier; Richard L. Ward [5 7] ABSTRACT An electric heater assembly includes a housing comprising a pair of generally similar wall portions and further includes an elongated heating coil supported from the inside of said housing by a plurality of spaced and staggered insulating support members in a sinuous path extending transversely back and forth in a first plane and in a second plane. The coil is assembled to the respective wall portions while they are in an openly accessible side-by-side relationship. The wall portions are then closed like a clamshell to form the heater assembly with the coil supported on the interior surface thereof.

7 Claims, 3 Drawing Figures HEATER ASSEMBLY FOR DRYER BACKGROUND OF THE INVENTION 1. Field of the Invention This invention relates to heating apparatus and more particularly to an electric heating assembly for a clothes dryer.

2. Description of the Prior Art Electric heater assemblies shown in prior art patents commonly include a supporting frame having insulating members through which a heating coil is threaded prior to insertion into the heater housing. Though the frame is ultimately supported by the heater housing or associated structure, the coil itself is supported by the frame. Because of the additional cost involved in providing the internal supporting frame, it would appear desirable to support the coil more directly on the internal wall of the housing. Simple elimination of the frame from prior art teachings, however, complicates the assembly of the heater. Thus the need for an improved heater assembly is shown.

SUMMARY OF THE INVENTION It is an object of the instant invention to provide an improved heater assembly in which the heating coil is supported on the internal wall of the heater housing without an intermediate coil supporting frame.

It is a further object of the instant invention to provide an improved heating coil assembly in which the housing is formed into generally similar wall portions to which the coil is assembled prior to the closing of the wall portions like a clamshell to form a heater assembly having the coils supported on the inside thereof.

It is a further object of the instant invention to provide an improved method of fabricating a heater assembly including the fabrication of a housing into generally similar wall portions and the assembly of a portion of an elongated coil to each wall portion prior to the closing of the wall portions like a clamshell to form a heater housing having a heater coil supported on the inside wall thereof.

The instant invention achieves these objects in an electric heater assembly having a generally cylindrical housing formed as generally similar wall portions to which an elongated heating coil is assembled prior to the closing and connecting of the wall portions to form a housing having a continuous heating coil supported by the wall portions.

Operation of the device and further objects and advantages thereof will become evident as the description proceeds and from an examination of the accompanying two pages of drawings.

BRIEF DESCRIPTION OF THE DRAWINGS The drawings illustrate a preferred embodiment of the invention with similar numerals referring to similar parts throughout the several views wherein:

FIG. 1 shows an overall view of a clothes drying apparatus partially broken away and sectioned to show the embodiment of the instant invention;

FIG. 2 shows a view of the heater assembly as taken along lines 2--2 of FIG. 1; and

F IG. 3 shows a plan view of the heater assembly at an intermediate stage of fabrication.

DESCRIPTION OF A PREFERRED EMBODIMENT Referring to FIG. 1 there is shown the overall construction for a clothes dryer including a cabinet assembly comprising a sidewall wrapper 11 having generally vertical opposite side panels 13 and a rear panel 14. The sidewall wrapper 11 is supported on a base 15 which in turn is supported on a horizontal surface through a plurality of adjustable feet 16. The cabinet assembly further comprises a front panel 19 and top cover 20 supported on the sidewall wrapper 11. The top cover 20 includes an upwardly extending housing 21 for accommodating selected controls for the dryer.

The front panel 19 defines a generally central access opening 23 and includes a door 24 hinged on the front panel 19 and operable between open and closed positions relative to the access opening 23. The door 24 includes an outer panel 25 substantially flush with the front panel 19 and an inner panel 26 having a portion that extends rearwardly into the access opening 23. A seal 29 supported by the inner panel 26 extends endlessly around the rearwardly extending portion of the inner panel 26 for engagement with a recessed portion 30 of the front panel 19 to effectively provide an air sea] at the access opening 23.

Disposed within the cabinet assembly is a pair of spaced apart generally

vertical bulkheads

33 and 34. The rear bulkhead 34 is fixed to the sidewall wrapper 11 by a pair of brackets such as the bracket 35 that includes a front flange connected to the bulkhead 34 and a rear flange connected with the rear panel 14. The front bulkhead is similarly connected to the front flanges of wrapper 11 with a pair of brackets.

A generally cylindrical peripheral sidewall 36 is disposed between the

stationary bulkheads

33 and 34. At the front and at the rear of the peripheral sidewall 36 there are inwardly turned flanges comprising relatively

short end walls

39 and 40 juxtaposed the front and

rear bulkheads

33 and 34 and cooperable with the sidewall 36 to effectively define a fabric tumbler 41. A plurality of baffle members 43 are fixed to the peripheral sidewall 36 and extend into the tumbling chamber for assisting in the movement of fabrics therewithin during rotation of the fabric tumbler 41.

The front and

rear bulkheads

33 and 34 include radially outwardly disposed

recess portions

44 and 45 extending'axially toward the front and toward the rear, respectively, of the dryer l0.

Seals

49 and 50 are fixed to the

bulkheads

33 and 34 in the

recesses

44 and 45 and are engageable with the

tumbler end walls

39 and 40 to provide an air sea] at the ends of the tumbler 41. The

bulkheads

33 and 34 also include generally

annular portions

51 and 53 inwardly disposed from the

recesses

44 and 45 that effectively provide extensions of the

end walls

39 and 40 of the fabric tumbler 41.

The seal member 49, for example, disposed between the stationary bulkhead 33 and the rotatable tumbler 41 is shown as a U-shaped or channeLshaped felt member having a pair of generally outwardly extending

legs

54 and 55 connected by an intermediate arcuate portion. The leg 54 is fixed, as with adhesive, to the stationary bulkhead 33 in the recess 44 so that the intermediate arcuate portion conforms generally to the corner radius 56 and effectively biases the other leg 55 into engagement with the front wall 39 of the tumbler 41. The felt may be coated on one side with an antifriction layer such as polytetrafluoroethylene to provide a smooth, more durable, and lower friction running surface for engagement with the tumbler end wall 39.

The front bulkhead 33 defines an access 57 into the tumbling chamber that is substantially aligned with the access opening 23 in the front panel 19. The rear bulkhead 34 defines an opening 58 to receive a perforate panel 59 through which airflow is directed into the tumbling chamber 60 from a duct system as will be shown.

The tumbler 41 is supported on a generally horizontal axis by a system including a pair of rollers 61 supported on brackets 62 fixed to the rear bulkhead 34 and by a pair of slide bearings (not shown) supported by similar brackets fixed to the front bulkhead 33. The tumbler 41 could be supported entirely on rollers or entirely on slides as conditions permit.

The fabric tumbler 41 is rotated by a belt 63 encompassing the periphery of the tumbler sidewall 36 and driven by a motor 64 mounted on the base 15.

The airflow system for the clothes dryer includes a heater assembly 66 supported adjacent the base and into which air is drawn from the atmosphere for heating prior to movement into the fabric tumbling chamber 60. The heater assembly 66 accommodates an electric heating unit as will be shown in greater detail hereinafter. The heater assembly 66 is connected to a generally upwardly extending rear air duct 68 which conducts heated air from the heater assembly 66 through the rear perforate panel 59 and into the tumbling chamber 60.

The air then flows from the chamber 60 through a fil- I ter assembly 69 into the front air duct 70. The filter assembly 69 includes a filter screen 73 supported within the air duct 70 for removing lint particles from the air flowing out of the tumbling chamber 60 into the front air duct 70.

The air is drawn from the front air duct 70 into a blower assembly 74 from which it is forced through a rearwardly extending lower air duct 75 to atmosphere. The blower 74 includes an impeller (not shown) that is driven by the motor 64 mounted adjacent to the blower 74 on the base 15. The general airflow pattern within the drying apparatus 10 is shown by the broken and solid line arrows in FIG. 1.

Referring to FIG. 2, there is shown the heater assembly 66 in greater detail with a view looking longitudinally into the generally cylindrical and circular housing 78 in which a resistance heating coil 79 extends transversely back and forth across the housing 78 in two planes as will be more fully shown hereinafter. It is noted that the housing 78 -is formed of sheet metal and includes two generally similar halves or

wall portions

80 and 81 joined along mating outwardly extending longitudinal flanges such as 82 with a plurality of screws 83.

Extending inwardly from the housing is a plurality of coil support members 84 comprising a spring clip member 85 engageable with openings in the wall portions and retained therein by barbs on the spring clips 85. The spring clips 85 receive and retain ceramic insulators 86 through which the heating coil 79 passes. The coil 79 is thus supported on the interior wall of the housing 78. The two ends 87 and 88 of the elongated heating coil 79 are connected to

terminals

90 and 91 that include ceramic insulators. The

terminals

90 and 91 extend through and are insulated from the

housing walls

80 and 81 for connection to a heating circuit.

It is clear that the assembly of the coil supports 84 to the inner surface of the housing 78 would be difficult at best with the housing 78 in a generally cylindrical elongated form as in FIGS. 1 and 2.

The instant invention thus provides for the forming of the housing in halves or generally similar wall portions and 81 and the assembly of the heating coil 79 to openly

accessible wall portions

80 and 81 prior to the closing thereof for forming the cylindrical housing 78.

The instant invention is believed best explained by considering an assembly sequence. Referring to FIG. 3 there is shown the housing halves or

wall portions

80 and 81 with the interior thereof openly accessible. In this position the insulating support members 84 and the elongated resistance coil 79 are conveniently assembled to the two

wall portions

80 and 81 by a sequence of steps exemplified by the following:

a. The terminals and 91 to which the ends 87 and 88 of the coil 79 will be connected are assembled to the first and

second wall portions

80 and 81;

b. The insulating support members 84 are threaded loosely onto the coil 79 in the proper number to support the coil 79 in both of the

wall portions

80 and 81 in a desired pattern;

0. A first end 87 of the coil 79 is connected to the terminal 90 in the first wall portion 80;

d. The support members 84 are sequentially connected to the first wall portion 80 in a sequentially spaced and staggered relationship to form a sinuous pattern of the coil 79 extending back and forth transversely across the first wall portion 80 as in FIG. 3;

e. An unconnected support member designated as numeral 94 and an unsupported portion of the coil 79 is left between the two

wall portions

80 and 81;

f. The remaining support members 84 are sequentially connected to the second wall portion 81 to position the coil 79 in a sinuous pattern extending transversely back and forth across the second wall portion 81.

g. The other end 88 of the coil 79 is connected to the terminal 91 in the second wall portion 81;

h. The two

wall portions

80 and 81 are closed like a clamshell with the upper wall portion 80 in FIG. 3 being moved to an overlying position with respect to the lower wall portion 81;

i. Screws 83 are driven through the outwardly extending flanges 82 to securely fasten the two

wall portions

80 and 81; and

j. The remaining previously unconnected support member 94 is connected to the housing 80 at the position shown in FIG. 2, and indicated by broken lines 95 in FIG. 3, to support the intermediate previously unsupported loop.

It should be noted that the specific sequence of connection of the

ends

87 and 88 of the coil 79 to the

terminals

90 and 91 and the connection of the support members 84 to the

wall portions

80 and 81 may be altered from that described hereinabove. For example, the support members 84 may all be connected to the

wall portions

80 and 81 prior to the connection of the

ends

87 and 88 of the coil 79 to the

terminals

90 and 91. Likewise, both ends 87 and 88 of the coil 79 may be connected to the

terminals

90 and 91 prior to the connection of the support members 84 to the

housing walls

80 and 81. It is also noted that the support members 84 may all be assembled to the

housing walls

80 and 81 and then the coil 79 threaded through the coil support members 84 to achieve the sinuous pattern shown in FIG. 3.

There are certain advantages associated with positioning the support members so that the coil extends transversely back and forth across the housing rather than extending longitudinally. With the arrangement shown fewer clips are required since the vertical spacing between the two planes of coils and between the lower plane and the bottom of the housing provide greater clearance for coil sag while heated.

It is thus seen that the instant invention provides a heater assembly having an improved construction and method of assembly over that previously shown for drying apparatus. The invention provides not only an improved device by reducing the chance of shorting of the coil to the housing under conditions of coil sag but also provides an improved heater assembly from the standpoint of reduced fabrication and assembly cost by completely eliminating the conventional heater support rack previously used for supporting the coil within the housing.

In the drawings and specification there is set forth a preferred embodiment of the invention and although specific terms are employed these are used in a generic and descriptive sense only and not for purposes of limitation. Changes in form and the proportion of parts as well as the substitution of equivalents are contemplated as circumstances may suggest or render expedient without departing from the spirit or scope of this invention as defined in the following claims.

I claim:

1. An electric heating system for a fabric drying apparatus, the combination comprising: an elongated generally cylindrical housing comprising first and second wall portions connected together and open at both ends for airflow therethrough; a plurality of electrically insulated heater coil support members attached to each of said wall portions and arranged in rows along opposite sides in each of said wall portions in spaced-apart relationship; a terminal means connected to each of said wall portions and electrically insulated therefrom; an elongated coil of resistance wire comprising a heating coil and connected on one end to a first terminal means and extending to and supported in a first plane by the support members attached to said first wall portion and then extending to and supported in a second plane generally parallel to said first plane by the support members attached to said second wall portion and finally extending to and connected with a second of said terminal means for openly supporting said heating coil within said housing spaced inwardly from said wall portions to heat air flowing therethrough; and means for effecting airflow through said housing.

2. An electric heating system as defined in claim 1 wherein said coil support members are consecutively staggered between the opposite rows in each wall portion and connected thereto for supporting said heating coil in a sinuous pattern in each of said planes.

3. An electric heating system as defined in claim 1 wherein the longitudinal axis of said housing is generally horizontal and wherein the support members attached to said first wall portion are positioned alternately on opposite sides thereof to support a portion of said heating coil on a sinuous path in said first plane within said first wall portion generally parallel to the longitudinal axis of said housing and further wherein other support members are similarly attached to said second wall portion to support another portion of said heating coil on a sinuous path in said second plane within said second wall portion generally parallel to the longitudinal axis of said housing.

4. An electric heating system as defined in claim 3 wherein the planes of said heating coil portions are generally horizontal and parallel and wherein an intermediate loop portion of said heating coil connects the two coil portions and is supported by an additional support member.

5. An electric heating system for a fabric drying apparatus, the combination comprising: an elongated generally cylindrical housing comprising first and second generally similar mating wall portions connected together as a unit and open at both ends for airflow therethrough; a plurality of electrically insulated heater coil support members attached to each of said mating wall portions and arranged in rows along opposite sides in each of said wall portions in predetermined spacedapart relationship; a terminal means connected to each of said wall portions and electrically insulated therefrom; an elongated coil of resistance wire spaced inwardly from said wall portions and comprising an electric heating coil, a first'portion of said heating coil connected to and extending from said first terminal means to and supported in a first generally horizontal plane by a plurality of sequentially positioned support members on said first wall portion, a second portion of said heating coil connected to and extending from said second terminal means to and supported in a second generally horizontal plane by a plurality of sequentially positioned support members on said second wall portion, a connecting portion of said elongated heating coil extending between said first and second wall portions to form a continuous elongated heating coil extending from said first terminal means to said second terminal means and openly supported within said housing for heating of airflow therethrough; and means for effecting airflow through said housing.

6. An electric heating system as defined in claim 5 wherein the first portion of said heating coil is supported on a sinuous path by sequentially spaced and staggered support members in said first plane within said first wall portion and wherein the second portion of said heating coil is supported on a sinuous path by sequentially spaced and staggered support members within said second wall portion in said second plane generally parallel to and spaced from said first plane.

7. An electric heating system as defined in claim 6 wherein said connecting portion of the elongated coil comprises a loop extending between said first and second planes and supported by an individual support member fixed to one of the wall portions intermediate the two planes.

Claims

5. An electric heating system for a fabric drying apparatus, the combination comprising: an elongated generally cylindrical housing comprising first and second generally similar mating wall portions connected together as a unit and open at both ends for airflow therethrough; a plurality of electrically insulated heater coil support members attached to each of said mating wall portions and arranged in rows along opposite sides in each of said wall portions in predetermined spaced-apart relationship; a terminal means connected to each of said wall portions and electrically insulated therefrom; an elongated coil of resistance wire spaced inwardly from said wall portions and comprising an electric heating coil, a first portion of said heating coil connected to and extending from said first terminal means to and supported in a first generally horizontal plane by a plurality of sequentially positioned support members on said first wall portion, a second portion of said heating coil connected to and extending from said second terminal means to and supported in a second generally horizontal plane by a plurality of sequentially positioned support members on said second wall portion, a connecting portion of said elongated heating coil extending between said first and second wall portions to form a continuous elongated heating coil extending from said firSt terminal means to said second terminal means and openly supported within said housing for heating of airflow therethrough; and means for effecting airflow through said housing.