As household clothes dryers have developed, various assemblies have been employed to mount the dryer drum for rotation within the clothes dryer cabinet. Each of these assemblies have attempted to solve numerous problems in the art, and have met with varying degrees of success.
The most common design problems encountered in the clothes dryer art include reliability, useful life, ease of assembly, noise generation and transmission, maintenance, and cost. Solutions to these problems are sometimes a conflicting. For example, while it may be possible to make a clothes dryer which is reliable and has a long life, in the past such a machine would require periodic maintenance, would be difficult to manufacture, and would have an excessive cost.
One conventional drum mounting scheme mounts each end of the dryer drum for rotation upon a pair of idler rollers. The front of the drum is enclosed, about its circular rim, by a front felt seal carried by a front bulkhead. The rear of the drum is likewise enclosed by a rear felt seal carried by a rear bulkhead. The front and rear bulkheads are each attached to the dryer cabinet. In such a construction, the front and rear bulkheads and seals do not bear any of the weight of the drum.. Rather, the dryer drum is supported entirely by the front and rear pairs of idler rollers.
Although reliable, the aforementioned assembly requires the installation and maintenance of several idler rollers, which increases the assembly time and parts cost and, hence, increases the resulting cost of the clothes dryer. Furthermore, the idler rollers tend to become noisy as they wear and require periodic maintenance and/or replacement.
One attempt to improve upon the aforementioned conventional dryer is exemplified in U.S. Pat. No. 5,216,823, which is owned by the assignee of the present invention and incorporated herein by reference in its entirety. The '823 patent eliminates the idler rollers which commonly support the front end of the dryer drum and, instead, uses a bearing and seal assembly which includes a ring-like felt seal positioned between the open circular front end of the drum and a circular support flange coaxially nested within the front end of the drum. An upper arcuate portion of the felt seal has a plurality of thin, pad-like glides of wear-resistant plastic material fixed thereto. The pads are engaged by the drum and bear the weight of the front end of the drum. The bearing and seal assembly of the '823 patent reduces noise transmission, cost, and maintenance as compared to conventional dryers.
U.S. Pat. No. 5,363,569, which is also owned by the assignee of the present invention and incorporated herein by reference, improves upon the '823 patent by providing a bearing and seal assembly formed from a two-piece ring of lubricant impregnated felt. The felt ring has an upper portion which is formed of a relatively high density felt to bear the weight of the front end of the drum, and a lower portion which is formed of a relatively lower density felt. The two-piece felt ring of the '569 patent prevents or minimizes transmission of noise from the drum to the surrounding metal cabinet, and decreases the assembly time and cost of the dryer.
Another type of dryer construction is presented by U.S. Pat. No. 5,127,169, incorporated by reference herein, wherein the dryer drum is rotatably mounted between a rear bulkhead provided by a back panel of the dryer cabinet and a front bulkhead attached to a front panel of the cabinet. The front and rear ends of the dryer drum are sealed by front and rear sealing gaskets. Idler rollers support the weight of the rear of the drum, thereby increasing the maintenance, noise generation and transmission, and cost of the clothes dryer.
There exists a need in the art for a clothes dryer which is easy to manufacture, which reduces or eliminates noise generation and transmission, and which can be produced at a low cost.
USPTO Backgrounds
USPTO Backgrounds