CA2080085A1 - Electric resistance heater for clothes dryer - Google Patents

Abstract

Abstract of the Disclosure A heating unit (H) installable in a clothes dryer has first and second sections (S1, S2) which fit together to form the unit. A heater assembly (10) for the heating unit comprises an open coil heating element (62), and a plurality of insulators (16) to each of which a convolution of the coil is attachable. A
support (68) is provided on which the insulators are mounted in a spaced relation from each other. The insulators and support together form an insulator assembly installable in the unit. The support includes a flat plate section (74) on which the insulators are mounted and side pieces (76A, 76B) which attach the insulator assembly to a sidewall of one of the sections thereby to mount the heater assembly in the unit.

Description

sackaround of the Invention This invention relates to heater assemblies for use in clothes dryers and, more particularly, to an improved heater assembly in which is easier to fabricate and simpler to install.
In the manufacture of clothes dryers for household or commercial use, a heater assembly is usually fabricated by a supplier at his manufacturing site. Completed assemblies are then shipped to the appliance manufacturer where they are installed in the dryer as part of the assembly process. During this installation, the heater assembly is first installed in a mounting fixture and the fixture then installed in the dryer.
Heater assemblies comprise coils of open heating wire mounted on insulators which, in turn, are supported on wire rods. A set of electrical terminals are attached to the ends of the wire for insertion in an appropriate receptacle or socket. While a heater assembly is not flimsy, neither is it particularly rugged. As a practical matter therefore, the more a heater assembly is handled, the greater the risk it may become damaged and unusable.
In addition to the above, it is also disadvantageous to have so many parts required for the installation of the heater assembly. Besides the cost of the parts, the more parts there are, the more assembly time is probably required to manufacture an assembly. Added cost factors include enhanced inventories, etc. It thus would be beneficial to eliminate as many parts as possible, particularly if in doin~ so a way could be found to ,~."~ ~,;,, ,,, ,,,, . ,, ", .. . . .. .. .
' ~ , , :
, `` , , ` 208008~
also make a heater assembly less vulnerable to damage, for example, during shipment and installation.
Summary of the Invention Among the several.objects of the present invention may be noted the provision of a heater assembly for use in an appliance such as a clothes dryer; the provision of such an assembly which becomes part of a heating unit installed in the appliance rather than simply another part thereof; the provision of such an assembly which is readily interfaced with the heating unit to produce a unit which is readily installable in the appliance: the provision of such a heater assembly to facilitate a heating unit requiring fewer parts than prior units installable in the same type appliance; the provision of such a heater assembly which simplifies assembly of the heating unit prior to installation; the provision of such a heater assembly to use conventional insulator assemblies, or new integral insulator assemblies; the provision of such a heater assembly in which the potential of damage to a heater coil is reduced because handling of the assembly is greatly reduced; and, the provision of such a eater assembly which is designed to conform to a support structure within the appliance to provide an improved fit of the unit within the appliance and reduce potential damage which might occur when the appliance is moved.
In accordance with the invention, generally stated, a heating unit installable in a clothes dryer has first and second . ' `"' '; ':
,`: ` :: :
.'-: : , ,.
.: ;; ::
'` ` ' :'' ~ ::

: ` ': : , i, '' ~.- .,. :` ,, ` .: ``

. .

2~8008~
sections which fit together to form the unit. A heater assembl~
for the heating unit comprises an open coil heating element, and a plurality of insulators to each o4 which two or three convolutions of the coil are attachable. A support is provided on which the insulators are mounted in a spaced relation from each other. The insulators and support together form an insulator assembly installable in the unit. The support includes a flat plate section on which the insulators are mounted and side pieces which attach the insulator assembly to a sidewall of one of the sections thereby to mount the heater assembly in the unit. Other objects and features will be in part apparent and in part pointed out hereinafter.
Brief Description of the Drawings Fig. 1 is a schematic representation of the present invention in use in a clothes dryer;
Fig. 2 is a perspective view of an assembled heating unit ready for installation in the clothes dryer;
Fig. 3 is a perspective view of the heating unit of Fig.
2 with a heating assembly of the present invention being installed therewith;
Fig. 4 is an end view of the heater assembly;
Fig. 5 is a plan view of the heater assembly;
Fig. 6 is a side elevational view of the heater assembly;
Fig. 7A and Fig. 7B are elevational views of respective insulators used in the heating assembly;

2~80~85 Fig. 8 is a plan view of support on which insulators are mounted:
Fig. 9 is a perspective view of an alternate embodiment of the heater assembly;
Figs. 10 and 11 are respective plan and elevational views of a shallow pan heating unit section with a heater assembly installed;
Fig. 12 on the same sheet as Fig. 1 is a perspective view of another insulator support structure installable in the section of Figs. 10 and 11; and, Fig. 13 on the same sheet as Fig. 9 is a plan view of another support structure installable in the section of Figs. 10 and 11.
Corresponding reference characters indicate corresponding parts throughout the drawings.
Description of Preferred Embodiments Referring to the drawings, an appliance such as a clothes dryer is indicated generally D. The dryer has a tub U in which articles A of clothing, towels, or other articles to be dried are placed. A heating unit H is ins~alled in the appliance on one side of the tub, and a blower assembly B on the other side thereof. The heating unit includes a heater assembly 10 which is described in more detail hereinafter.
Blower B includes a blower motor M by which air is drawn into an air inlet I of the heating unit. This air is heated by heater 10 as it flows through the heater assembly. Tha air exits the heating unit at its upper end .: :
- .:
, . . ~ .
.

~ -.: ' ~

2~80085 through holes or perforations P formed in the outer shell S of the unit. The heated air is then drawn through the tub and over the articles to dry them, the heated air entering and exiting the tub through openings O formed in an outer wall W of the tub. The air is then discharged from the appliance after passing through the blower. As shown in Fig. 1, the heating unit is a vertically oriented unit in which the heater assembly is fitted into the lower end of the unit. The unit is designed to fit between inner and outer supports X and Y raspectively. The unit has a flange F
(see Figs. 2 and 3) which abuts against support X and are attachable to it by bolts. The outer support has a series of indentations Z vertically spaced from one another. The outer shell of the heating unit (including heater assembly 10) is contoured to matingly fit in these indentations and insure a snug fit of the heating unit in the appliance.
Heating unit H is shown in more detail in Figs. 2 and 3. In Fig. 2, the unit is shown with the heater assembly 10 in place, and in Fig. 3 with the heater assembly positioned for installation prior to installation of the unit in the dryer. The unit has a first shell section Sl and a second shell section S2.
When connected together, the upper end of the unit (as viewed in Fig. 1) is a closed end and the other (lower) end is an open end. Section Sl extends the entire length of the unit; while section S2 terminates at a point intermediate the length of the unit. When attached to each other, the sections define a hollow ` 2~80~8~i enclosure through which air is drawn. The enclosure is generally rectangular in cross-section with rounded corners corresponding to the curvature of the shell sections. As noted, perforations (not shown) are formed in the upper end of section Sl for heated air to escape the unit into the tub. Section S2 has rounded protruberances P shaped to conform to the indentations X to fit the unit in place in the dryer. The sections also have mating flanges F1 and F2 respectively for joining the sections together.
As noted, heater assembly 10 is connected to the heating unit at the lower end of section S2. Previously, the heating unit required a separate installation of a heater assembly within the unit. This not only complicated the design of the heating unit but also that of the heater assembly. Assembly of the heating unit took longer than is now require with the heater assembly of the present invention, thus increasing the cost of the appliance.
Referring to Figs. 4-6, heater assembly 10 is shown in more detail. The assembly first includes an least one open coil heating element 12. The coil is arranged to extend longitudinally of the assembly. An insulator assembly 14 includes a plurality of insulators 16 mounted, in a spaced relationship, on a support member 18. Two insulator assemblies 14A, 14B are shown in the drawings, although it will be understood that more or fewer insulator assemblies could be used. Various types of insulators can be used with the insulator ' ' " ' :

: . ~ ` . ' :
.:. ' . ' . :

`` 2~801~85 assembly. Shown in Figs. 7A and 7B are respective insulators 16A
and 16B. Shown in Fig. 8 is a support 20 on which the insulators are mounted. Support 20 includes a flat, metal plate 22 in which spaced openings 24A-24C are formed. Further, plate 22 may have stiffener beads 2S extending lengthwise of the support. If present, both of these beads, which are formed in a punching operation can extend in the direction (up or down) or one in each direction. Each insulator has opposed, centrally located slots 26A, 26B respectively. To install an insulator in the support, the insulator is inserted through the opening and the respective slots fitted into the edge of the support adjacent the opening.
This is effected by positioning the insulator parallel to the longitudinal axis of the support. Once positioned, the insulators are twisted in the openings until they are orthogonal to the longitudinal axis. This is the position of the insulators shown in Figs. 4 and 5. The insulators have respective notches 28A, 28B formed on each side of their upper and lower ends. A
separate convolution of coil 12 is received in each notch for the insulators to support the upper and lower reaches of the coil as it is installed in the assembly. Again, it will be understood that while coil 12 is shown to have three upper and three lower reaches in the Figs., the heater assembly could have a different configuration in which the coil has more or fewer reaches. In addition to the insulator assembly described above, heater assembly 10 can also employ an insulator assembly in which the ' ' ' ' : :

': ' ' ~' ' ' ~`
: ', ' ;
,, .
'' ' ' ~ , :

~ . :

2~0~8~
insulators and support are formed of a compatible, ~usible material which allows the insulators and support to be fused into an integral assembly. Such an insulator assembly is disclosed in co-pending United States patent application 774,715 which is assigned to the same assignee as the present application.
The insulator assembly is installable in a pan 30. The pan has sidewalls 32A, 32B, and a base 34. The sidewalls have spaced, horizontal slots 36 in which tabs 38 formed at each end of the supports 22 are received. One end of the support has a 95- bent tab inserted into a slot at an angle, then brought back parallel with the bottom of the pan locking the bent tab and enabling the other differently designed tab to be inserted into the opposite slot. After insertion, this tab is twisted or bent to lock the insulator assembly in place. As seen in Figs. 4 and 6, coil 12 extends beyond the upper end of the sidewalls. As shown in Figs. 4 and 5, a terminal block 40 i8 mounted in sidewall 32B. The block extends vertically of the sidewall and has two terminals 42A, 42B for electrically connecting the heater assembly into a heating circuit of the appliance. The respective ends 44A, 44B of coil 12 are connected to the terminal block to connect coil 12 in the heating circuit.
Pan 30 iB generally U-shaped in cross-section. The ends of pan 30 are open, and the heater assembly, when installed, helps define the open end portion of the heating unit. The upper end of each sidewall is outwardly turned to form respective _ g _ .. . . . .
~, ""'' '' ,: ', ', .; -'' '' ' ~': .

- ,. -,--~

, .
.

208008~
flanges 46A, 46s. These flanges interface with flange Fl of the heating unit when the heater assembly is installed. Each flange has a screwhole 48 which registers with a corresponding screwhole in flange Fl. Screws 50, insertable through the screwholes, help connect the heater assembly to the heating unit once the heater assembly is installed. It will be noted that the length of the flanges 46A, 46B are less than the length of the pan. The section of the pan along which these flanges do not extend forms a lip 52 which is insertable beneath the back edge 54 of heating unit section S2. To install the heater assembly 10 with the heating unit, heater assembly is positioned as shown in Fig. 3 to the rear of section S2. The heater assembly is held at an angle with respect to the heating unit so lip 52 is beneath the back edge of section S2. Heater assembly 10 is then pushed forward so the lip extends along the inside of the section until the flange portion of the pan sidewalls abut against back edge 54. The screwholes 48 on the flanges should then align with the screwholes in flange Fl and the screws 50 are then inserted to attach the heater assembly to the unit.
It is a feature of the heater assembly that pan 30 be contoured so to facilitate installation of the heating unit in the appliance. For this purpose, pan 30 has three, parallel, hump shaped protruberances 56A, 56C extend orthogonally to the longitudinal axis of the pan. This humps are spaced along the length of the pan with hump 56A being at the end of the pan ` ' "

' ~ ~ ~`J

2~80085 adjacent section S2, hump 56B slightly rearward thereof, and hump 56C adjacent the opposite end of the heater assembly. Each hump begins at one sidewall of the pan, extends along the base of the pan, and terminates at the other sidewall. In addition, a protruberance 58 extends from hump 56A rearwardly of the pan to a point just short of hump 56C. This protruberance also extends from one sidewall of the pan to the other across the base of the pan. It subsumes the portion of hump 56B which extends across the base of the pan. As previously mentioned, and as shown in Fig. 1, the purpose of the humps is to provide a snug fit of the heating unit into the appliance, wherein the support Y has a corresponding contoured surface into which the humps fit. This makes it difficult to dislodge the installed heating unit either during movement of the appliance from one place to anather, or by ~ibrations which occur during normal use.
What has been disclosed is a heater assembly which becomes an integral part of an installed heating unit. In prior appliance applications, a heater assembly was installed within a heating unit, not as part of it. This construction required more components, took longer to make, and was not as reliable as the heater assembly of the present invention. The disclosed heater assembly further can take advantage of advances in insulator assembly construction to further increase its reliability.
Referring now to Figs. 9-13, alternate embodiments of the heater assembly are shown. With respect to Fig. 9, section 01961~/4369 : "

:.
' :'. ' . , :

--2~8008~

S1' of a heating unit H' has a deeper pan than the other section of the heater (not shown). A heater assembly 60 is directly installable into section S1' adjacent the open end of this section.
Assembly 60 first includes an least one open coil heating element 62. The coil extends longitudinally of the heating unit when the heater assembly is installed in section S1'. An insulator assembly 64 (three of which are shown in Fig.
9) includes a plurality of insulators 66 mounted, in a spaced relationship, on a support member 68. It will be understood that more or fewer insulator assemblies could be used. Again, various types of insulators, such as those shown in Figs. 7A and 7B, could be used with the insulator assemblies. The support 68 shown in Fig. 9 includes a flat, metal plate 70 in which spaced openings 72 are formed. The openings are identical to the openings 24A-24C described with respect to support 22 of the previous embodiment. The insulators are installed on the support in the manner previously described, and separate convolutions of coil 62 are fitted in the respective notches formed in the insulators. With three insulators mounted on the respective plates 70, the heater assembly will have three courses extending both above and below the plates. Again, more or fewer insulators could be mounted on each plate, and the number of courses would change accordingly. It will be understood that an integral insulator assembly such as disclosed in co-pending .

2~8008~
application 774,7l5 could be used in this embodiment.
In Fig. 9, the plates 70 are shown to have a flat, central section 74 in which the openings 72 are formed, and downwardly turned side pieces 76A, 76B which are narrower in width than section 74. The side pieces taper in width from their end joining section 74 to their distal end. Each side piece also has an opening 78 in their distal end for attaching the insulator assembly to a sidewall 80 of section Sl'. The overall width of the insulator assemblies correspond to the inner width of section Sl', for the insulator assemblies to fit within the section.
Attachment of the insulator assemblies to the sidewall can be performed in any convenient manner. For example, the sidewall can have openings 82 corresponding to the openings 78 in the side pieces. A screw 84, bolt, or other fastener can then be used to attach the insulator assembly to the sidewall. Or, the side pieces can be welded to the inner face of the sidewalls.
As an alternative to the embodiment of Fig. 9, Figs. 10 and 11 illustrate a shallow pan section S2' of the heating unit H'. Section S2' has a circumferential flange F2'. A heater assembly 67' is for installation in this heating unit section.
Because of the shallowness of the pan, the heater assembly will substantially extend above the sides of the section. This is unlike heater assembly 60 in which generally covered by the sidewalls of section Sl'.

"., . '' ' `' : ' ,:.:, . .

,~
',: ' ' ' ~ : ,~ ~ , ;. : ' - ,: : -'r,' ~'' ~: ' ''', ' , ' `. ' ' :~' . .~ `~":' ~. ., ". : . :. ' .,:: -. . . -~ . ' :. .: '. .

2~8D08~

Referring to Fig. 12, the heater assembly 67 is shown to have a support member 68' (three of which are shown in Figs. 10 and 11). Each member includes a plate 70' having a flat, central section 74' in which openings 72A'-72C' are formed. The plate also has side pieces 76A', 76B' which of narrower in width than section 74'. At the lower end of each side piece is an outwardly turned tab section 84A, 84B respectively. The tab sections each have an inner portion 86A, 86B of the same width as the side pieces, and an outer, narrower width section forming respective tabs 88A, 88B. Openings corresponding to the width and thickness of the tabs are formed in the sidewall of section Sl' and the tabs fit into these openings to install the insulator assemblies in place.
Regardless of which support member is used, the heater assembly is installed in section Sl' of the heating unit prior to mating of the other section of the heating unit with section Sl'. Because the heater assembly is directly installable to section S1', rather than on come other element which is then installed in the heating unit, heater assembly 60 requires fewer parts than previous heater assemblies required, and the heating unit takes less time to assemble than previously.
In view of the foregoing, it will be seen that the several objects of the invention are achieved and other advantageous results are obtained.

... ~.,, ,,,,, .,, , ` ~
": :

,~;
, '~ , ' `': `~
, : ' ~ ,' ' ' '': ,: ~ ' ~ , ' j, ~ ''` , . ~ :
'`;` ' ' . , : :
-2080~8~

As various cnanges could be made in the above constructions without departing from the scope of the invention, it is intended that all matter contained in the above description or shown in the accompanying drawings shall be interpreted as illustrative and not in a limiting sense.

i` : '`,. '' ' ' , ' . ,., .. , . .' ~,. , ::: :

: ~ , ' . . , . ~ - . ' . . - .

.. . .

Claims (13)

1. In a heating unit for installation in a clothes dryer, the heating unit having first and second sections which fit together to form the unit, a heater assembly comprising:
at least one open coil heating element;
a plurality of insulators to each of which at least one convolution of the coil is attached; and, support means on which the insulators are mounted in a spaced relation from each other, the insulators and support means together forming an insulator assembly installed in the unit, with the support means including means for attaching the insulator assembly to a sidewall of one of the sections thereby to mount the heater assembly in the unit, the heating unit having a closed end and an open end and the heater assembly being attached to said one section at said open end of the heating unit.

2. The heater assembly of claim 1 wherein the support means includes a first section on which the insulators are mounted, and side pieces at each end of the first section which are downwardly turned with respect thereto, the respective side pieces being attachable to a sidewall of said section.

3. The heater assembly of claim 2 wherein each side piece has an outwardly extending tab and the sidewall has openings therein in which the tabs are received.

4. The heater assembly of claim 3 wherein one heater section has a shallower pan than the other section and the support means is installed in the section with the shallower pan.

5. The heater assembly of claim 2 wherein each side piece has an opening therein and the sidewall has corresponding openings therein, and the assembly further includes fastening means inserted through the openings to attach the support means to the section.

6. The heater assembly of claim 5 wherein one heater section has a deeper pan than the other section and the support means is installed in the pan with the deeper section.

7. In a heating unit for installation in a clothes dryer, the unit having a first and second sections extending the length of the unit, the improvement comprising a heater assembly installed within the sections and comprising an open coil heating element, a plurality of insulators to each of which at least one convolution of the coil is attached, and a support on which the insulators are mounted in a spaced relation from each other, the insulators and support means together forming an insulator assembly, the support including means for attaching the insulator to a sidewall of one of the sections thereby to install the heater assembly within the unit, the heating unit having an open end and a closed end and the heater assembly is attached to said one section at said open end of the heating unit.

8. The improvement of claim 7 wherein the support means includes a first section on which the insulators are mounted, and side pieces at each end of the first section which are downwardly turned with respect thereto, the respective side pieces being attached to a sidewall of said section.

9. The improvement of claim 8 wherein each side piece has an outwardly extending tab and the sidewall has openings therein in which the tabs are received.

10. The improvement of claim 9 wherein one heater section has a shallower pan than the other heater section and the support means is installed in the section with the shallower pan.

11. The improvement of claim 9 wherein each side piece has an opening therein and the sidewall has corresponding openings therein, and the assembly further includes fastening means inserted through the openings to attach the support means to the section.

12. The improvement of claim 11 wherein one heater section has a deeper pan than the other section and the support means is installed in the pan with the deeper section.

13. A heater assembly for heating air comprising:
a heating unit having first and second mating sections which when mated together form an air inlet at one end for air to be heated to be drawn into the heating unit, one of the sections having a deep pan and the other section a shallow pan with the shallow pan section having air outlets formed in its end opposite the air inlet end for heated air to be drawn out of the heating unit; and, a heater assembly for heating the air, the heater assembly being attached to one of the sections adjacent the inlet of the heating unit and comprising an open coil heating element, a plurality of insulators to which at least one convolution of the coil is attached, and support means for the insulators including means for attaching the support means to a sidewall of the section thereby to install the heater assembly in the heating unit.