Bearings – Rotary bearing – Antifriction bearing
Reexamination Certificate
1999-11-02
2001-09-11
Hannon, Thomas R. (Department: 3682)
Bearings
Rotary bearing
Antifriction bearing
C193S037000, C198S842000
Reexamination Certificate
active
06287014
ABSTRACT:
CROSS-REFERENCE TO RELATED APPLICATION(S)
None.
BACKGROUND OF THE INVENTION
In a belt conveyor, the function of the roll is to support the rubber belt and the material being transported, allowing for the rolling movement of the belt. These rolls consist of a cylindrical tube (or shell), and rolling bearings, supported by and fixed to the roll's shaft. The shaft is supported by a frame (or brackets) which in turn is supported by the structure of the conveyor. The rolling bearings of a roll are generally retained to its shaft by means of a spring steel retaining ring, mounted on the shaft and against which a front face of the bearing inner ring rests.
Prior art contemplates a sealing system that aims at offering adequate protection against the entry of dust and moisture while retaining the grease or oil that is necessary for the lubrication of the rolling bearing. The useful life of rolling bearings of a belt conveyor, even if they are correctly dimensioned for the load conditions to which they are subjected, will be severely reduced by contamination if the seal does not offer an adequate protection against the entry of dust and moisture.
In previous constructions, the rolling bearing is generally fixed to the cylindrical tube of the roll by means of a bearing housing (generally a steel sleeve or stamped metal) welded to the end of the cylindrical tube. The bearing housing (or end bell) bends inwardly parallel to the shaft, creating a cavity into which the rolling bearing is press fit. This inward protrusion of the center of the end bell also houses, the various parts that compose the sealing system of the roll, generally of the contact or labyrinth type. The sealing systems are meant to keep dust from entering the roll bearing from outside the roll, and grease from escaping to the inside of the roll.
In these known constructions, the rolling bearing is placed inside the housing, and is separated by a distance D, from the adjacent end of the shaft. The shaft is supported on the structure of the conveyor at the end of the shaft. This support method reduces the load bearing capacity of the roll, by increasing the bending moment of the roll, causing angular deflections in the roll at the bearings. Thus, the useful bearing life is reduced.
Another problem with the known designs of the support roll is the risks posed by the possible fatigue failure of the weldment that affixes the bearing housing to the cylindrical shell. Due to the position of the rolling bearing in relation to the location of the weld, the bearing housing is subjected to an alternating bending moment, thus creating a high risk of failure by fatigue. Specifically, the bearing housing is welded to the adjacent end of the cylindrical shell. The roll bearing is supported by the bearing housing at a position separated from the adjacent end of the roll. Therefore the bearing is separated axially along the roll a distance E. The axial distance E allows for the creation of the bending moment about the roll bearing.
In addition to the inconveniences associated with failed roll assemblies there is the associated damage the failed roll causes to the belt. The damage is in the form of cuts and tears in the belt cover that shortens its life.
In designs where the support is a ring-shaped housing, (generally made of steel), securing parts of the roll (such as by welding) make the roll production work time consuming. On the other hand, attempts to simplify the fixation between components were both problematic and economically unfeasible due to the reduced tolerances required when producing the parts of the assembly. This was particularly the case when applying rigid parts for the ring-shaped housing and for the end element in order to axially lock the cylindrical tube to the shaft.
BRIEF SUMMARY OF THE INVENTION
The present invention refers to a construction arrangement for the housing and sealing of the end bearings of a support roll of a belt conveyer.
More particularly, the present invention provides a belt conveyor roll of reduced cost which eliminates the use of points of welds and spring steel retaining rings to affix the bearing housing to the cylindrical tube and the bearing to the roll shaft respectively. The invention permits the use of components with ample dimensional tolerances.
Additionally, the present invention provides a roll, which allows the sealing of the region where the rolling bearing is mounted to the roll shaft, with a system of small diameter contact lips that present a small radius. Sealing labyrinths are used to avoid the escape of grease or any other lubricant from the shaft region where the rolling bearing is, and also prohibit the entry of dust or moisture to the region where the rolling bearings are mounted.
The inventive belt conveyor roll has a shaft supporting the inner ring of a rolling bearing adjacent to each end of the shaft. The inner ring locks against axial displacements in the direction of the shaft. The outer ring of the rolling bearing supports a cylindrical shell mounted so as to encompass the shaft. The roll also comprises a ring-shaped bearing housing that presents a peripheral external surface which is fitted, through elastic deformation, into a superficial internal undercut in the cylindrical shell, so that the shell locks radially and axially to the ring-shaped housing. The bearing housing also has an internal peripheral surface against which the outer ring of the adjacent rolling bearing is seated and retained against radial and axial displacements.
REFERENCES:
patent: 3313168 (1967-04-01), Matthews
patent: 3610387 (1971-10-01), Vom Stein
patent: 4344218 (1982-08-01), Hooper et al.
patent: 4955462 (1990-09-01), Bilodeau et al.
patent: 4972939 (1990-11-01), Uttke et al.
patent: 5261528 (1993-11-01), Bouchal
patent: 5944161 (1999-08-01), Sealey
patent: C2-3 238634 (1984-04-01), None
patent: A1-0 112 026 (1984-06-01), None
patent: A-2 047 845 (1980-12-01), None
patent: B-139 635 (1973-08-01), None
patent: B-448 365 (1985-03-01), None
Enduride Technology, “Enduride conveyor idler rolls . . . ”, Camese Compendium, p. 21 No Date.
Enduride Brochure, “Enduride Super Roll”, pp. 1-4 No Date.
Enduride Brochure, “Facts About The New Enduride Belt Conveyor Rollers”, pp. 1-6 No Date.
Hannon Thomas R.
Kinney & Lange , P.A.
Svedala Industries Canada, Inc.
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