US 3721015 A
A clothes drying machine having a self-lubricating plastic sleeve bearing secured to the rear wall of a rotating drum, and the stationary harder surfaced steel stub shaft for rotatably supporting the drum and bearing assembly is fixed to the machine cabinet.
Description (OCR text may contain errors)
United States Patent 11 1 1111 3,721,015
Sisler et al. ]March 20, 1973 BEARING ASSEMBLY  References Cited  Inventors: Robert R. Sisler, Louisville, Ky.; UNITED STATES PATENTS Claude Blake New Albany 3,094,376 6/1963 Thomas ..308/DIG. 7  Assignee: General Electric Company, Louis- 3,106,991 10/1963 Winge ....308/DIG. 7 vi11e,Ky 3,218,732 1l/l965 Alaback ..34/133  Fil d; S t 23, 1971 Primary Examiner-Carroll B. Dority, Jr.
AttorneyWalter E. Rule et al. 21 Appl. No.: 183,032
 ABSTRACT 52 u.s.c1. ..34/133, 308/l5,308/22, A clothes drying machine havigg a Semubricating 308/238 plastic sleeve bearing secured to the rear wall of a 511 11 1. c1 ..F26b 11/02 rotating drum and the stationary harder surfaced Steel  new of Search ""34/133, 139; 308/ 3 68 5512 7* stub shaft for rotatably supporting the drum and bearing assembly is fixed to the machine cabinet.
3 Claims, 3 Drawing Figures PATENTEU HARZO I875 F'IG.
BEARING ASSEMBLY BACKGROUND OF THE INVENTION This invention relates generally to a bearing assembly for rotatably supporting a drum in a clothes drying machine.
Traditionally rotating drums in domestic clothes dryers have been customarily mounted in a cantilever fashion with a single support bearing structure at the rear of the cabinet. For instance US Pat. No. 3,009,259 by W. F. Simpson assigned to the same assignee as the present invention, shows a bearing support assembly in which the stub shaft has been fixedly mounted to the drum for rotation therewith, while the bearing material has been mounted to the machine cabinet or other rigid member on said cabinet. With this arrangement as the stub shaft rotates within the bearing it rides only on the lower section of the bearing surface and failure of the bearing occurs when the stub shaft wears through the lower area of the bearing.
It has also been proposed to fix the stub shaft to the stationary cabinet so that it does not rotate and secure the bearing, which is usually made of a softer material than the stub shaft, to the drum for rotation therewith. Such an arrangement is shown in US. Pat. No. 3,218,732 to G. J. Alabock. However these attempts have resulted in costly structures not conducive to mass production assembly operations.
SUMMARY OF THE INVENTION By this invention, there is provided an improved low cost, self-lubricating bearing support arrangement for use in a clothes drying machine having a rotating drum. This arrangement includes a flanged plastic bearing which is placed in an opening in the rear wall of the drum and secured to the drum wall by threading a locking member on the outer surface of the bearing to lock the drum wall between the flange and the locking member. This assembly is then placed on a metal stub shaft which is fixedly mounted in the cabinet and held thereon by securing a holding member to the free end of the stub shaft. This arrangement allows the softer bearing material to rotate with the drum around the harder stub shaft so that all of the bearing surface comes in contact with the shaft in one revolution of the bearing. The distribution of wear over the entire bearing surface greatly reduces the wear rate of the bearing material and increases bearing life. The axial movement of the rotating drum is controlled by the axial dimensions of the sleeve bearing and the stub shaft thus proper tolerances are built into the design of the bearing and adjustments during assembly are unnecessary.
BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic side elevational view of a clothes dryer suitable for incorporation of the invention, the view being partly broken away and partly in section to illustrate details;
FIG. 2 is a cross-sectional view, partly broken away, line 2-2 in FIG. 1; and
FIG. 3 is an exploded perspective view of the bearing assembly of one embodiment.
DESCRIPTION OF THE PREFERRED EMBODIMENT Referring now to FIG. 1, the machine illustrated is a domestic clothes dryer generally indicated by the numeral l0. Dryer 10 is provided, in the usual way, with a cabinet or housing 12. Within the cabinet 12 is provided a fabric tumbling chamber, or drum 13, mounted for rotation on a substantially horizontal axis. Drum 13 is generally cylindrical in shape having an outer cylindrical wall portion 14, a front wall 15 and a rear wall 16. A plurality of clothes tumbling ribs 18 are provided on the interior of wall portion 14 to lift fabrics as the drum rotates, and then allow them to tumble back to the bottom of the drum.
The front of the drum is rotatably supported within cabinet 12 by suitable bearing pads 19 secured on a circular flange 20 forming the inner part of the loading opening 22 behind door 23. Preferably, one pad is positioned on each side of the highest point on flange 20 so as to provide a stable support for the outwardly turned flange 24 formed in front drum wall 15.
The rear of the drum 13 receives its support by means of a bearing assembly 26 which forms an embodiment of the present invention and will be described hereinafter.
In order to provide for the flow of a stream of drying air through the drum 13, an air inlet opening 27 is provided in the cabinet 12. Ambient air is drawn into the opening 27 by a blower 28 driven by a motor 29. The air drawn into the opening 27 is conveyed upwardly through a conduit 31 formed by a housing 32 and the rear wall of the cabinet 12. The upper end of housing 30 has openings 33 formed therein so that the air flows from the conduit 31 through openings 33 and over heating elements 34 into the drum 14 through perforations 36 provided in the rear wall of said drum. The air outlet from the drum is provided by perforated openings 37 in the door 23. The bottom wall section of the door and adjacent wall of the cabinet are provided with aligned openings 38 and 39 so that air may travel from the door to a discharge duct 40.
In addition to driving blower 28, motor 29 rotates the drum 13. To this end the motor 29 is provided with pulley 42 which has an endless belt 43 extending over it, and completely around the cylindrical wall 14 of the drum.
With reference to FIGS. 2 and 3 more specifically the bearing assembly 26 comprises a bearing member 45, a locking member 46 and a stub shaft 47.
The bearing 45 consists of a shank portion 48 which extends into a centrally located opening 49 in the rear wall 16 of the drum [3. The inner end of the bearing 45 has a flange 51 which acts on the inner surface of wall 16. The bearing 45 provided in the instant embodiment is of a self-lubricating plastic, such as 44 percent Teflon, 51 percent Nylon and 5 percent molybdenum disulfide, however other self-lubricating materials are available and may be applied without departing from the present invention. In order to insure that the bearing 45 rotates with the drum l3 and does not rotate relative to it, there are provided on the shank 48 adjacent the flange 51 tabs or projections 52. The tabs 52 are circumferentially disposed around the shank and engage appropriately spaced notches 53 disposed around the opening 49 when the bearing is positioned with its flange 51 against the inner surface of drum rear wall 16. To hold the bearing 45 on the drum 13 the free end of shank 48 is threaded to receive the locking member 46. As shown in FIG. 2 the bearing 45 is secured to the drum by the locking member acting against the outer surface of the drum wall.
Extending axially through the bearing 45 is a centrally located bore 50 for receiving the stub shaft 47. The stub shaft has a reinforcing plate 54 staked thereon which is secured by suitable means such as screws to the housing 32. As best seen in FIG. 2 the drum 13 and bearing assembly 26 is retained on the stub shaft 47 by a retaining or holding plate 56 held against the forward end of the stub shaft 47 by a suitable screw 57. Should it be desired to remove the drum 13 it is merely necessary to remove screw 57 and slide the assembly off the stub shaft 47.
With the drum mounted as shown in FIGS. 1 and 2 the axial movement of the drum 13 between the housing and the holding plate 56 is predetermined by the amount the axial dimension of the stub shaft 47 is greater than the axial dimension of the bearing 45. Thus in assembling during manufacturing the axial movement of the drum is controlled by the tolerance of the parts and the need for adjustments are eliminated.
In operation, the plastic bearing 45 which is of softer material rotates with the drum while the harder steel shaft 47 remains stationary. With this arrangement all of the bearing surface in the bore 50 comes into contact with the shaft during each revolution of the drum. Bearing wear is greatly reduced by equally distributing any wear around the entire bore 50 of the bearing 45. For bearing failure due to excessive bearing wear to occur in the present embodiment of the invention the bearing material would have to completely wear away. In practice, this event would not be within the design life of the appliance.
While there has been shown and described a specific embodiment of the present invention, the invention is not limited thereto and it is intended by the appended claims to cover all modifications falling within the true spirit and scope of the invention.
1. A fabric drying machine comprising:
a housing having an access opening, said access opening having an axially inwardly extending annular ring flange;
a generally cylindrical fabric-receiving drum positioned within said housing on a horizontal axis, the
front wall of said drum having an opening formed with an axially outwardly extending drum flange overlying and in spaced relation to the inwardly extending ring flange;
means disposed between the upper portion of said ring flange and said drum to support said front wall;
bearing means for rotatably supporting the rear end of said drum comprising;
a centrally located opening in the rear drum wall having circumferentially disposed notches;
a plastic self-lubricating sleeve bearing including a shank section extending into said opening and a flange at one end thereof for engaging the inside of said rear dru m wall; a portion of said shank ad acent said flange having a plurality of tabs circumferentially disposed around said shank for engagement with said notches to prevent relative rotational movement between said bearing and said drum;
a portion of said shank between the tabs and the free end thereof being provided with threads;
a locking member threaded on said threaded portion and acting against the outside of said rear drum wall for securing said rear drum wall against axial movement between said locking member and said flange;
a stub shaft fixedly secured to said housing;
a centrally located bore in said bearing for receiving said stub shaft for rotatably mounting said bearing and drum;
holding means fastened to the free end of said stub shaft for holding said bearing and drum on said stub shaft between said housing and said holding means;
whereby said hearing when rotated with said drum on said stub shaft allows the complete inner circumferential bearing wall of said bore to ride on said stub shaft to insure uniform wear of said bear- 2. A fabric drying machine as set forth in claim 1 wherein the axial dimension of said stub shaft is greater than the axial dimension of said bearing to control the axial movement of said drum between the housing and said holding means.
3. A fabric drying machine as set forth in claim 1 wherein the plastic bearing contains molybdenum disulflde.