Abstract:
A bearing for supporting the drum of a clothes dryer which includes an interior structural layer of high coherency felted fibrous material and an exterior surface covering for contact with the dryer drum formed of fibrous material including a wool constituent. The felted interior provides support and noise damping character while the exterior surface covering provides friction reduction and enhanced flame retardancy.

Description:
FIELD OF THE INVENTION 
     The present invention relates generally to bearing structures and, more particularly, to a bearing assembly for rotatably mounting and supporting a drum in a clothes dryer 
     BACKGROUND 
     Bearing and seal assemblies for use in supporting relation to rotating drums within clothes dryers are generally known. Such assemblies used in the past have included pliable ring structures incorporating materials such as surface pads of felt disposed at selected regions within the ring structure to dampen the vibration and noise associated with the rotation of the dryer drum. One prior assembly incorporating a felt seal with felt of different density disposed at different regions around a split ring bearing with a friction reducing powder coating across an upper wear surface is disclosed in U.S. Pat. No. 5,363,569 to Kadakia, the teachings of which are incorporated by reference herein. Another prior assembly is disclosed in U.S. Pat. No. 5,216,823 to Ripley the teachings of which are incorporated by reference herein in which the bearing is comprised of a ring of felt-like material having an upper portion of relatively dense felt and a lower portion of relatively less dense felt. The upper portion includes wear-resistant pads which bear the weight of the drum. 
     While bearing assemblies of the prior types may provide rotational support for the front end of the dryer drum, the use of wear resistant coatings or surface pads may add complexity to the manufacturing process. Moreover, such assemblies may be prone to premature loss of friction resistance if a pad becomes displaced or if a section of the friction reducing coating is preferentially worn away. Since clothes dryers are typically used for a number of years, such premature degradation is generally undesirable. 
     SUMMARY OF THE INVENTION 
     The present invention provides advantages and alternatives over the prior art by providing a bearing for supporting the drum of a clothes dryer which includes an interior structural layer of high coherency felted fibrous material and an exterior surface covering for contact with the dryer drum formed of fibrous material including a wool constituent. The felted interior provides support and noise damping character while the exterior surface covering provides friction reduction and enhanced flame retardancy. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The present invention will now be described by way of example only, with reference to the accompanying drawings which constitute a part of the specification herein and in which: 
     FIG. 1 is a front perspective view of a domestic clothes dryer; 
     FIG. 2 is an exploded perspective view of the clothes dryer of FIG. 1, illustrating a bearing assembly in accordance with the present invention; and 
     FIG. 3 is a cut-away side view of a section of the bearing assembly of FIG.  2 . 
    
    
     While the invention will hereinafter be described in connection with exemplary illustrated embodiments, it is to be understood that in no event is the invention to be limited to such illustrated and described embodiments. On the contrary, it is intended that the present invention shall extend to all alternatives and modifications as may embrace the principles of this invention within the broad spirit and scope thereof. 
     DESCRIPTION OF PREFERRED EMBODIMENTS 
     With reference to FIG. 1, a clothes dryer  10  of the domestic type which incorporates a bearing in accordance with the present invention is illustrated. The clothes dryer  10  has a box-like cabinet formed from painted sheet metal, as is well known in the art. The dryer  10  includes a horizontal top panel  12  with a control console  14  extending along its rear edge. The control console allows the user to regulate the operation of the clothes dryer  10  to provide drying of clothes placed within the dryer in a predetermined manner. The dyer  10  further includes a pair of vertical side panels  16  and  18 , and a vertical rear panel (not shown). 
     A vertical front panel  20  provides an access opening  22  which is normally closed by a door  24  that is hinged along its left edge, as shown, for movement about a vertical axis. When the door  24  is open as shown in FIG. 1, a user can reach through the access opening  22  and into the interior of the clothes dryer  10  to insert clothing therein or remove clothing therefrom. 
     Turning to FIG. 2 of the drawings, the clothes dryer discussed with regard to FIG. 1 can be seen to include, in addition to the front panel  20 , a drum support panel  30 , a bearing assembly  40  in accordance with the present invention, and a dryer drum  60  that, in operation, rotates on a horizontal axis  70 . 
     The front panel  20  provides an inner surface  21  having an inner periphery  21   a  which defines, in part, the access opening  22  (see FIG.  1 ). The front panel  20  also provides a seat against which the door  24  seals during operation of the dryer  10 . A conventional switch (not shown) is provided adjacent the front panel to preclude operation of the dryer without closure of the door  24  against the front panel  20 . 
     The drum support panel  30  has a generally planar, plate-like front portion  32  that is fixed by suitable mechanical means to the inner surface  21  of the front panel  20 . With further reference to FIG. 2, the drum support panel  30  includes, in addition to the plate-like front portion  32 , a transition ring  33  that is generally annular in shape. 
     The transition ring  33  has extending horizontally from its outer circular periphery a circular drum support flange  34  which is inwardly spaced from the plate-like front portion  32 . The transition ring  33  extends inwardly from the plate-like portion  32  to support the circular drum support flange  34  at a relatively inwardly displaced position. When assembled, by welding or suitable mechanical fastening means, the front panel  20  and the drum support panel  30  are fixed in position relative to each other and constitute a substantially unitary structure. 
     The bearing assembly  40 , in accordance with the invention, rotatably supports the front end  62  of the dryer drum  60 , the rear end (not shown) of the drum  60  being supported by conventional means. The assembly  40  preferably includes an upper load bearing portion  42  of a interior felt material  43  (FIG.3) adjoined in needled relation to a fibrous surface layer  44  defining a low friction bearing surface  46  (FIG. 2.) 
     The interior felt material  43  is of a density and coherency such that that it distributes applied loads and prevents substantial compacting of the load bearing portion  42  due to the load or weight of the front end  62  of the dryer drum  60 . It is contemplated that the interior felt material may be of either a single layer or a multi-layer construction. One exemplary multi-layer construction is illustrated in FIG. 3 wherein the interior felt material  43  is made up of a first layer  47  in substantially adjacent relation to the surface layer  44  with at least a second layer  48  extending away from the first layer  47 . 
     One contemplated method for manufacture of a multi-layer construction is to incorporate a light weight heat activated fabric adhesive between layers of felted batting and to needle adjacent layers of felted batting across the fabric adhesive followed by heat activation of the adhesive to retain the coordinated structure. An exemplary process and resulting multi-layer high density felted materials suitable for use in the present invention is provided in commonly assigned pending U.S. patent application Ser. No. 09/576,720 the contents of which are incorporated herein in their entirety. Of course other production processes may also be utilized if desired. 
     According to a potentially preferred practice, the interior felt material  43  is formed by needling long-staple synthetic fibers such as polyester or the like. By way of example only other materials may include polypropylene, polyamide, acrylic, aramid fibers. Of course, blends of any of the foregoing may also be used. If desired, a percentage of natural fibers such as wool or the like may also be added. The use of long staple synthetic fibers is particularly preferred to enhance tensile strength and to reduce elongation. According to one potentially preferred practice, the interior felt material  43  may include a percentage of fibers including a low melting point constituent such as low melting point polyester fibers or bicomponent polyester fibers having a core of high melting point polyester and a sheath of low melting point polyester. Such low melting point constituent fibers may be added directly during blending of the fibers making up the interior felt material  43  and are entangled with the other fibers during needling of the interior felt material. 
     The surface layer  44  which contacts the drum  60  is preferably of a nonwoven construction formed by needling or the like although other fibrous constructions including woven or knitted constructions may likewise be utilized if desired. The material forming the surface layer  44  is preferably wool or a blend of wool and synthetic fibers such as polyester or the like as described above. The use of a wool constituent in the surface layer  44  is believed to substantially reduce friction with the drum  60  while substantially improving flame retardancy. It is also contemplated that other friction reducing materials may be blended with the fibers forming the surface layer or may be applied after formation. 
     As illustrated, an underlying containment layer  49  may be disposed across the side of the interior felted material  43  facing away from the surface layer  44 . However, it is also contemplated that the containment layer  49  may be eliminated if desired. If an underlying containment layer  49  is utilized, the material forming such containment layer is most preferably a wool or wool blend as used in the surface layer  44 . However, it is contemplated that virtually any material having adequate flame retardancy character may be utilized. 
     As shown, the surface layer  44  and the containment layer  49  are preferably needled in juxtaposed relation to the interior felt material  43  to form a substantially coordinated sandwich structure. That is, during the formation process, fibers from the surface layer  44  and the containment layer are carried into and intermingle with the fibers of the high density felt material. If desired, an adhesive layer may be disposed between the surface layer  44  and the interior felt material  43  and/or between the containment layer  49  and the interior felt material to further enhance the attachment. 
     According to one exemplary manufacturing process, the surface layer  44 , the interior felt material  43  and the containment layer  49  are each formed separately to have a substantially equivalent density. One potentially preferred density range is about 432 to about 576 pounds per cubic yard. However, one or more layers may have substantially higher or lower densities if desired. The individual layers are thereafter brought together at a needling station for final needling into a substantially coordinated composite structure. This needling operation may be either a single pass or a multiple pass needling operation. By way of example, if the interior felted material  43  is required to be extremely dense and/or extremely thick, it may be desirable to needle batts of material forming the surface layer  44  and containment layer  49  through opposing sides in separate operations. 
     Once the layers of the load bearing portion  42  have been combined by needle punching, the resulting structure is preferably subjected to heat and pressure such as in a flat pressing or calendering operation. As will be appreciated, this process activates any low melting point constituents to further enhance coherency by causing the low melting point constituent to flow and thereby form a bonding matrix within the interior layer. This bonding matrix may also promote the ability of the interior layer to carry loads applied during use. In addition, the pressurized heat activation causes the interior layer to compress thereby increasing the overall density and strength of the interior layer  43  such that the density of the interior layer  43  in the resulting product is slightly higher than the density of the other layers. In addition, the application of heat and pressure imparts a smooth uniform contact area for contact by the dryer  60 . 
     As illustrated, the bearing  40  includes a lower band portion  50  also referred to as a wiper of felted material such as wool or the like extending away from either end of the load bearing portion  42  for disposition in surrounding relation to the drum support flange  34 . As shown, the lower band portion has a width such that it may be folded upon itself during installation thereby forming a seal at the forward edge of the drum  60 . As illustrated in FIG. 3, the ends of the lower band portion  50  may be adhered to the load bearing portion by the application of seams  52  such as sewn seams or the like between the lower band portion and an extended lip portion  54  of the load bearing portion  42 . A substantially stable ring-like structure is thereby formed. 
     It is, of course, to be understood that while exemplary embodiments have been illustrated and described, in no event is the invention to be limited to such illustrated and described embodiments since modifications may be made and other embodiments of the principles of this invention will no doubt occur to those of skill in the art. Therefore, it is contemplated that the invention shall extend to all such modifications and other embodiments as may fall within the true spirit and scope of this invention.