Plastic bearing dryer idler

An idler pulley assembly for tensioning a belt drive for a clothes dryer or other belt driven appliance. The idler pulley assembly provides a spring steel support anchored to a base of the clothes dryer, a Y-shaped bracket connected to the spring steel support and holding an idle pulley at an opposite end. The idle pulley is mounted on an open cross section, C-shaped shaft which is fixed at opposite arms of the Y-shaped bracket. An oil impregnated wick is inserted into the shaft which deposits oil on an inside surface of the idler pulley journaling the shaft.

BACKGROUND OF INVENTION 
The present invention relates to clothes dryers having a rotating drum for 
tumbling the clothes, and a belt drive system therefor. In particular, the 
present invention relates to a belt tensioning apparatus for maintaining 
an adequate belt tension between a drive pulley and the drum. 
It is known to provide a dryer drum having a belt wrapped around the drum 
and wrapped around a drive pulley which is rotatably driven by an electric 
motor. It is also known to provide a idler pulley spring mounted to a 
dryer cabinet and resiliently urged against the belt to take up slack in 
the belt. Such an arrangement is generally described, for example, in U.S. 
Pat. Nos. 4,300,293 and 4,488,363. 
With the known idler pulley assemblies, an effective and practical method 
of applying lubrication to the pulley during operation is not disclosed. 
Additionally, it is not provided in the known idler pulley assemblies to 
provide lateral guides to assist locating the belt onto the pulley during 
assembly. 
SUMMARY OF THE INVENTION 
It is an object of the present invention to provide an improved dryer idler 
pulley assembly. It is an object to provide such an assembly for a 
simplified and highly reliable belt system for a clothes dryer. It is an 
object to provide an efficient fabrication and assembly of a clothes 
dryer. It is an object to provide a long lasting, maintenance free drive 
assembly for the dryer. 
The objects of the invention are achieved in that a dryer idler pulley 
assembly is provided having a pulley mounted on a rolled shaft which has a 
segment around its circumference open. The rolled shaft thus is 
approximately C-shaped and interfits within a journal area of the dryer 
idler pulley. An oil saturated wick is located within the rolled shaft 
extending through said open segment which places oil on a pulley bearing 
surface as its rotates around the shaft, and cleans the pulley bearing 
surface at the same time. The pulley itself has a sectionalized rim 
instead of a continuous rim which assists in the manufacturing process. 
The alternating sectioned rim on the plastic pulley allows single access 
pull in a mold used to form the pulley. 
The assembly consists of a spring steel idler bracket having two arms 
spaced apart in parallel fashion, the bracket formed integrally with a 
V-shaped spring support tabbed into the dryer base, a high wear plastic 
pulley having a bearing surface incorporated into the pulley journal 
design, a rolled steel shaft polished to the required micron finish and 
snapped into the bracket, and an oil impregnated wick which provides 
continuous lubrication throughout the life of the complete idler assembly. 
The wick is preferably substantially triangular in cross section with an 
edge extending out of the shaft against the bearing surface. The shaft has 
C-shaped extensions at opposite ends to frictionally engage into D-shaped 
apertures formed into the two arms. 
The idler shaft has substantially a C-shape, or a D-shape having a section 
of the straight stem of the "D" removed. The idler bracket arms each have 
an extension protruding inwardly toward each other. These extensions are 
located below the idler wheel. The length and placement of the extension 
prevents the belt from being mislocated to the shaft surface during the 
assembly operation. The idler bracket and the spring support are 
preferably stamp-formed from spring steel stock.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
FIG. 1 illustrates a clothes dryer 10 having external paneling 12 with a 
tiltable door 14 covering a clothes access opening 16 for placing wet 
clothes into a drum 20 for drying. The drum 20 is supported by a plurality 
of roller bearings 24 arranged below the horizontal axis of the dryer 
drum. Mounted to a floor or base 28 is a motor support 30 which supports 
an electric motor 34 having a horizontal drive shaft 36 holding a drive 
pulley 40. A control panel 44 is provided on a top side of the dryer which 
contains controls for temperature, speed, duration, etc. of the dryer 
operation. 
FIG. 2 illustrates a belt drive system 50 of the present invention. The 
drive pulley 40 and the drum 20 are wrapped by a belt 54. An idler 
assembly 60 of the present invention presses against and thus tensions the 
belt 54. The assembly 60 comprises a idler pulley 64 mounted to rotate on 
an idler bracket 66 connected to, or formed integrally with, a spring 
support 68 which is connected to the base 28 of the dryer. Also shown in 
FIG. 2 is a wiring arrangement 70 including connectors and relays for the 
motor 34 as well as wiring 74 leading from the assembly 70 to the dryer 
control panel 44. 
The spring support 68 provides a base portion 68a having an extending 
offset tab 68b at a distal end and a peg portion 68c in a central area. 
The extending offset tab 68b and the peg portion 68c engage into slots 
69a,b in the dryer base. A base end 68d of the support 68 is connected to 
a lever portion 68e which extends upward to the bracket 66. The support 68 
is designed having a thickness, bending resistance, and material selection 
to maintain its V-shape, between the lever portion 68e and the base 
portion 68a, and resiliently resist an opening up of the V-shape. By so 
doing, the support 68 provides the pressing force of the pulley 64 against 
the belt 54. 
FIG. 3 illustrates the bracket 66 extending downward into the lever 68e, 
the two components preferably integrally formed as a stamped spring steel 
part. The bracket 66 and the lever 68e provide a stamped raised portion or 
rib 80 to add rigidity at this location. The raised portion 80 extends 
from the bracket 66 downward on the lever 68e for substantially the entire 
length of the lever. Likewise the bracket 66 provides two arms 82, 84 
having stamp-formed raised portions 86, 88 to add rigidity to these 
members. 
The two arms 82, 84 provide inwardly directed extensions 82a, 84a having 
triangular shapes which act as belt guides to prevent the dryer belt from 
locating between an arm 82, 84 and the pulley 64 during installation of 
the assembly 60. These extensions can also be stamp-formed integrally with 
the bracket 66. A shaft 90 having a generally C-shaped cross section is 
provided spanning between the arms 82, 84 and tightly fit within D-shaped 
apertures 92 of the arms 82, 84 (as shown in FIG. 5). The idler pulley 64 
provides a central journal 96 which is threaded by the shaft 90. As shown 
in FIG. 3, the pulley 64 further provides a belt receiving circumferential 
surface 64a for receiving the belt 54. The journal 96 rotates on the shaft 
90. The shaft 90 is formed by a rolled steel plate, into an approximate 
C-shape, in particular, a D-shape missing a center portion of the upright 
stem of the "D". The surface of the shaft is polished to a smooth finish. 
Within the C-shaped shaft is inserted an elongate wick 100, formed of 
felt, foam or similar material, and having an approximate triangular cross 
section with a rounded leg 102 ("pie-shaped"). The rounded leg 102 fits 
closely within the C-shaped cross section of the shaft and the opposite 
apex 104 protrudes outwardly through an open area of the shaft to press 
against an inside bearing surface of the journal 96. The wick 100 is oil 
impregnated, such oil impregnation to last the effective lifetime of the 
dryer 10. 
As shown in FIG. 4, a radially extending disk 64b connects the journal 96 
to the circumferential belt receiving surface 64a. As shown in FIGS. 3 and 
4, extending from the surface 64a are segmental, circumferentially spaced 
belt guiding tabs which are staggered across a width of the pulley 64 with 
tabs 64c on opposite sides of the belt guiding surface 64a. This staggered 
arrangement allows for easy molding of the pulley using a single axis mold 
pull, which reduces manufacturing costs. 
As shown in FIGS. 5-7, the shaft 90 comprises C-shaped extensions 106a,b on 
opposite axial ends of the shaft. The C-shaped extensions 106a,b fit 
tightly within the D-shaped apertures 92 at the arms 82, 84. 
As understood from the drawings and descriptions thereof, the idler 
assembly 60 can be assembled into the dryer without screw fasteners which 
provides an assembly time savings. The assembly 60 is installed to the 
belt 54 with reduced chance of misalignment of the belt to the pulley 64 
due to the extensions 82a, 84a. A reduced assembly cost can be realized. 
The shaft and wick arrangement provide for long, useful life of the 
assembly 60 and provides for smoother and quieter operation. 
Although the present invention has been described with reference to a 
specific embodiment, those of skill in the art will recognize that changes 
may be made thereto without departing from the scope and spirit of the 
invention as set forth in the appended claims.