SEALING DEVICE FOR PILLOW BLOCKS

Abstract: An improved alignment device and/or sealing device for creating an alignment of seals in split pillow blocks. An alignment device (21) having a cylindrical member surrounding a shaft (3) includes a plurality of sacrificial bearings (24) fitted to the inside diameter of the carrier or alignment device (21) and fixing the radial and angular position of the carrier and anything (20) which is permanently attached to the carrier. This radial location of the carrier and/or elements attached thereto permits the seal (20), carrier (21), and housing (1), to be selfaligned in conformance with the bearing (not shown), shaft (3), and housing (1). The positioning of the carrier and/or anything permanently attached thereto, with respect to the shaft, is accomplished by projections (28) and a resilient deformable element (31) fitted between the housing (1), and the alignment device (21) of this invention. This invention permits the self-aligning of the bearing, the shaft, the seal, and alignment device to the housing.

Description: SEALING DEVICE FOR PILLOW BLOCKS BACKGROUND OF THE INVENTION Industry has long used self-contained bearing and housing units designed to support heavy rotating shafts . These bearing units require adequate lubrication for the bearings . The lubrication must be retained in the housing unit and in addition, contaminants such as debris, dirt, etc. must be kept out of the housing unit, out of the lubrication, and away from the bearing in order to ensure smooth operation. These self-contained units are commonly known as pillow blocks and/or plumber blocks. The types and sizes cover virtually all applications that employ the use of heavy, and sometimes long, shafts in equipment such as road building, conveyors, fans, etc. In most cases, spherical roller bearing ' s are employed in the housings or pillow blocks in order to accommodate angular, radial, and axial shaft displacement that results from loading and, in some cases, thermal growth of the shaft. The angular displacement of the shaft may also result when heavy radial loads are applied some axial distance from the bearing mounting position. In the normal pillow block, a small amount of angular misalignment to the shaft can be tolerated because of the spherical shape of the outside diametric surface of the bearing. However, the seals associated with the pillow block have not been able to accommodate this angular displacement except by making the seal flexible and/or having a larger than desired amount of tolerance between the shaft and the sealing surface. The normal, severe duty, pillow block is horizontally split, and the top half can be removed for convenient inspection and installation of the shaft, bearings, and seals. In the prior art, there have been many different systems for sealing split pillow blocks including lip seals, springs, V-rings, felt, grease pockets and relatively rotating rings forming a labyrinth seal sometimes called a disc pack or taconite seal . These sealing devices and arrangements including combinations of the aforementioned systems have not been particularly successful because of misalignment between the seal and shaft. Constant maintenance and attention is required in order to ensure continued operation of the equipment (i.e. the shaft does not bind and/or seize) . All of the presently known means of sealing pillow blocks are ineffective because of the imperfect radial positioning of the sealing mechanisms or devices. The devices are ineffective and imperfectly positioned because of the non-concentricity of the housing and sealing mechanisms with respect to the bearing bore and shaft. All of the prior sealing mechanisms were affixed and positioned relative to the bearing housing and designed to permit or have a concentric offset to permit misalignment of the shaft with respect to the housing and/or the sealing device. The seals all were designed to accommodate the variance in the shaft angle, as noted before, either by making the contacting surfaces of material such as felt, etc. or having sufficient radial clearances between the sealing device and the housing to accommodate the variance in the angular displacement of the shaft . This prior art was improved with a use of the resilient members on a radially projecting member on the carrier in a recess on the housing as described and claimed in U.S. Patent No. 5,335,921 issued to Orlowski . SUMMARY OF THE INVENTION These prior art sealing mechanisms did not perform adequately partly because of the variations in circumferential pressure and the resulting friction or disassociation on the sealing surface due to the misalignment of the shaft with respect to the housing and seal . The present invention circumvents and has none of the deficiencies of the known prior art sealing devices . This invention includes means for maintaining the sealing device radially aligned with the shaft and also for locating and maintaining the sealing device independent of the housing bore's outside diameter. This invention locates itself and the related sealing device perfectly along and aligned with the shaft both radially and axially so that it will follow any movements of the shaft and not be restricted by the housing attitude. In accordance with the invention, there is provided a means in either the carrier for the sealing device or, in the event of a unified carrier and sealing device, the sealing device itself for radially positioning the carrier and/or the sealing device with respect to the shaft. This arrangement or innovation utilizes temporary bearing surfaces, sometimes called a skate, fitted tightly to the shaft for proper positioning of carrier or seal with respect to the shaft. Upon the rotation of the shaft, a portion of this bearing surface is worn away or sublimated to permit free rotation of the shaft but the remaining surface remains in close proximity to the shaft. The angular displacement of the prior art as described in Orlowski, by keeping the seal aligned with the shaft, was an improvement. However, in operation, limitations were encountered as a result of imperfect pivoting action of the housing with relationship to the carrier. The resilient members and the projections constrained the limits of alignment. The resilient members, due to their elastic units, would resist the motion and the forces of misalignment were not applied in the most efficient manner. The rectangular or right angular forms of the projections and the recesses may also impose limits on the movement of the alignment device. This invention provides for the movement of the projections on the carrier to be related to the movement of the centerline of the shaf . The recess in the housing is not necessarily cone-shaped as in the prior art to permit a larger movement within the housing without restrictions from either the resilient members or the structural members . The housing is fixed and the shaft bearing seal and alignment device are self-aligned to the housing. The advantages of this invention are that the carrier and/or sealing device is always aligned both radially and axially with the shaft and the alignment forces and reactions are maximized by the action being correlated to the centerline of the shaft. Another advantage of this invention is that the alignment is performed easily, and yet with a retention force necessary to retain the alignment against small and/or short variations in forces causing the misalignment. The third advantage is that the curvature on the surface of the projection is the radius as determined from the centerline of the shaft thereby ensuring that any movement required to correct misalignment will be accurate and responsive. When the two parts of the split housing are tightened securely to each other, this innovation not only provides a fixed axial position and fixed radial alignment for the seal, but also permits angular misalignment of the housing with respect to the carrier and/or sealing device and the shaft. The advantages of this invention are that the carrier and/or sealing device is always aligned both radially, angularly, and axially with the shaft, thereby making any seal a more efficient barrier to the movement of the lubrication inside the housing and of the contamination outside the housing. DESCRIPTION OF THE DRAWINGS Fig. 1 is a side view of the invention showing a sealing device and/or the seal carrier surrounding the shaft and affixed to the housing of the pillow block, aligned with the shaft. Fig. 2 is a detailed view of the novel elements of the alignment device of the invention. DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT OF THE INVENTION The normal pillow block and its operation is shown and described in U.S. Patent No. 5,335,921 and will not be described herein. As noted in practice, such sealing devices were almost always misaligned to the shaft and bearing. Referring to Fig. 1, a portion of the housing 1 inside elevation, a seal mechanism 20, and the novel seal carrier and alignment mechanism 21 of this invention are shown as utilized in applicant's invention. The sealing device is of any desire type, but is shown as a sealing device 20 substantially as described in U.S. Patent No. 5,378,000, wherein the rotor 20a and stator 20b of the seal 20 are locked together to prevent axial movement of the sealing device 20. The alignment mechanism 21 of this invention may be separate from the seal 20 as shown or be made integral with the seal, if desired, without affecting the function. The sealing device 20, as shown, comprises the rotor 20a and the stator 20b axially held together by the 0-ring 27. The rotor drive O-ring 26 also serves as a seal . The novel improvements provided by the carrier and/or sealing devices of this invention are the alignment of the sealing device 20 and the carrier 21 radially, angularly and also with respect to the center line of the shaft 3. The carrier 21 and seal 20 are axially fixed to a predetermined location on the shaft 3. The novel aligning and positioning elements 24, which are normally made of Teflon ® or some other sublimable or erodible sacrificial material, are then firmly abutted to the shaft 3. The carrier or aligning portion 21 includes projection 28 which fits into a groove 30 in the split housing l of the pillow blocks. Deformable material 31, which may be in the form of an O-ring or a flat strip, is fitted into the groove 30. The groove 30 may have either slanted or vertical wall members in the radial direction. In the prior art, the walls were required to conical in order to accept the upward and downward movement of the resilient material. In operation, after the alignment carrier 21 and/or seal 20 of this invention are inserted onto the shaft 3 and fitted into the housing 1 of the pillow block, the pillow block is placed into position and secured in a normal manner not shown. The radial alignment and positioning members 24, normally a material having a low co-efficient of friction as explained above, are now firmly abutted to the shaft 3. The radial alignment and positioning members 24 are sacrificed by being slightly worn away or sublimated when the shaft 3 is rotated. Thus, the radial alignment is maintained because the wearing action ceases as soon as there is zero contact between the elements 24 and shaft 3. The seal 20, whether integral with alignment member 21 or affixed thereto, is now permanently aligned with the shaft and bearings (not shown) . The seal 20 and carrier 21 are axially fixed with respect to the shaft 3 by the projection 28 entering into the recess 30 of the housing l. The resilient and deformable material 31 will prevent axial movement of the carrier and/or seal device 21 and 20. The deformable resilient material 31 will deform to accommodate the axial, radial, and angular misalignment of the housing respect to the shaft 3, seal 20, and bearings. This resilient material will be deformed without memory so that once the pillow block is secured, the alignment is maintained. If for any reason the pillow blocks and/or the bearings should be removed, the deformable material should be replaced prior to reassembly. Projection 28 may have either a flat surface or a surface which is the radius from the center line of the shaft 3. The curvature of the radial surface of the projection 28 will facilitate the alignment process. The resilience and the deformation capabilities of the material 31 permit the shaft 3 to be rotated about the center point of the bearings, not shown, and thereby facilitate conformance of the seal 20, carrier 21 to the center line of the shaft in a misaligned attitude to the housing. The housing 1 is automatically self-misaligned to the carrier and/or sealing device 21 and 20 and shaft 3, which are also all aligned with each other in a fixed manner. Any degree of misalignment may be accomplished by changing the size of the groove or recess 30 with respect to the size of the projection 28. The distance between the sidewall of the groove and the wall of the projection 28 will determine the amount of misalignment, which may be accommodated. The prior art having a tapered cavity 30 was limited in this respect due to the alignment action being taken not at the extremity of the projection 28, but rather accommodated by upward and downward movement of resilient matter in the cavity 30. This permanent self-alignment of the bearing, sealing device 20, and shaft 3 to the housing permits the operation of the shaft with an absolute minimum of heat generation or wear of the pillow block. The pillow block housing 1 and shaft 3 can now be easily aligned with other elements of the system to run true. Variations and other aspects of the preferred embodiment will occur to those versed in the art all without departure from the spirit and scope of the invention.

Claims: CLAIMS What is claimed is: 1. An alignment device for aligning a housing and a seal to a shaft in a split self-contained bearing housing unit where the housing unit includes means for securing together the split housing members comprising: a shaft generally supported by bearings in split housing units, each of said split housing units having at least one radial groove therein; a rigid circular member surrounding said shaft; at least two alignment elements axially displaced and positioned radially on said circular member and firmly abutting said shaft; an outwardly radially projection on said circular member having a predetermined axial width less than the width of the groove in said housing and a radial length less than the depth of said groove in said housing, said projection fitted in said groove in said housing; and a resilient member radially fixed in said housing in contact with said projection; said resilient member permitting axial, radial, and angular movement of said projection in said groove and resultant movement of said housing units relative to the center point of said bearing, thereby facilitating misalignment of the housing to the center line of the shaft and bearing. 2. An alignment device, according to Claim 1, wherein said alignment elements are made of a material having low co-efficient of friction. 3. An alignment device, according to Claim 2, wherein said alignment elements are made to conform to the surface of said shaft when said shaft is rotated. 4. An alignment device, according to Claim 3, wherein said alignment elements conform to the surface of said shaft by being worn away by the rotation of said shaft. 5. An alignment device, according to Claim 3, wherein said alignment elements sublimate upon rotation of said shaft . 6. An alignment device, according to Claim 3, wherein said alignment elements are made of Teflon ® . 7. An alignment device, as in Claim 1, wherein said resilient member is deformable. 8. An alignment device, as in Claim 7, wherein said resilient deformable member is an O-ring. 9. An alignment device, according to Claim 7, wherein said resilient deformable member is a flat strip. 10. An alignment device, according to Claim 1, having a sealing device permanently affixed to said circular member . 11. An alignment and sealing device for aligning and sealing the shaft in a split self-contained bearing housing unit including means for securing together the split housing members; bearing means in said housing unit; a shaft generally supported by said bearing (s) in said housing unit, wherein each of said split housing members has at least one opposing radial groove therein. Said alignment and sealing device comprising: a rigid circular member surrounding said shaft; at least two alignment elements axially displaced and radially positioned inwardly on said circular member and firmly abutting said shaft; an outwardly radial projection on said circular member having a predetermined axial length less than the groove in said housing and having a radial length less than the depth of said groove in said housing, said projection fitted in said groove; said circular member and sealing means, radially surrounding shaft; a resilient deformable member fixed to said projection and filling said resilient deformable member permitting axial, radial and angular rotational movement of said housing unit relative to the center point of said bearings when said housing units are secured together, thereby facilitating misalignment of the housing to the center line of the shaft and bearing.

Inventors: ORLOWSKI DAVID C, ORLOWSKI, DAVID, C.
Applicants: INPRO CO INC, INPRO COMPANIES, INC.
Application year: 1997
Main classification: F16C35
IPC codes: F16C33, F16C35