Patent Publication Number: US-2021188001-A1

Title: Sleeve for Wheel

Description:
BACKGROUND AND SUMMARY 
     The disclosure is directed to a sleeve for a wheel. More in particular, the disclosure is related to a sleeve for a wheel of a caster that may be removably inserted into a bore of a rotation surface, e.g., an inner race of a bearing, that is disposed in a hub of a wheel. The sleeve has an outer surface with a circumferential groove adapted and configured to receive a resilient ring. The resilient ring is configured to be compressible to allow the sleeve to be inserted into the bore of the rotation surface, e.g., the inner race of the bearing. The resilient ring is configured to be expandable outward when the sleeve is inserted through the bore of rotation surface, e.g., the inner race of the bearing, at distance that clears the effective axial length of the rotation surface. The outward expansion of the ring is greater than an inner diameter of the bore of rotation surface, e.g., the inner race of the bearing, and thus, the sleeve may be retained in the bore of the rotation surface to facilitate assembly of the caster with a yoke and axle pin. The resilient ring is also configured to be sufficiently deformable to allow the sleeve to be removed from the bore of the rotation surface as may be required during assembly of the caster. 
    
    
     
       DESCRIPTION OF DRAWINGS 
         FIG. 1  is a perspective view of an exemplary wheel used in a caster with an exemplary sleeve assembly installed in a hub of the wheel. 
         FIG. 2  is a perspective view of an exemplary sleeve assembly comprising a sleeve and resilient ring. 
         FIG. 3  is a cross-sectional view of the sleeve of  FIG. 2  taken along a longitudinal axis of the sleeve assembly. 
         FIG. 4  is a cross-sectional view of the wheel of  FIG. 1  taken along an axis of rotation of the wheel. 
         FIG. 5  is an enlarged view of detail area  5 - 5  of  FIG. 4 . 
         FIG. 6  is an exploded cross-sectional view of the wheel of  FIG. 4  showing assembly with an axle pin and yoke of the caster. 
     
    
    
     DETAILED DESCRIPTION 
     The description that follows refers to a sleeve assembly that is used with a wheel for a caster. The sleeve assembly may be used with other wheels as well. Referring to  FIG. 1 , the exemplary caster  10  has a wheel  12  with a hub  14 . The hub  14  may be monolithically formed with the wheel or may be integral with the wheel for instance, through an overmolding process, a press fit installation, mechanical and/or adhered connection as is known in the art. A rotation surface  16  may be disposed in the hub  14  and configured to allow the wheel  12  to rotate about a rotation axis  18 . The rotation surface  16  may define the radially innermost rotation surface of the wheel hub  14 . The rotation surface  16  may be a portion of the wheel hub, a bushing, a journal, a sleeve, or an inner race of a bearing disposed in the hub where the bearing has inner and outer races and rotational elements disposed between the inner and outer races. A rotation surface  16  may be provided on one axial end of the hub  14 , and a second rotation surface may be provided on the other axial end of the hub. The rotation surface  16  may extend partially through the hub  14 . The rotation surface  16  may have an axial length  20  and a bore  22  with an inner surface diameter  24 . For instance, as best shown in  FIG. 4 , a rotary bearing  30  is inset in a recess  32  formed in the side face of the hub  14  with an inner race  34  defining the rotation surface  16  with the inner race having the bore  22  with the inner surface diameter  24  and the axial length  20  extending partially through the hub. 
     Referring to  FIGS. 2 and 3 , the caster wheel  12  includes a sleeve  40  that may be insertable in the bore  22  of the rotation surface  16 . The sleeve  40  may have an outer surface  42 , and first and second opposite axial ends  44 , 46 . The first axial end  44  of the sleeve  40  may have a shoulder  48  extending radially outward from the outer surface  42  of the sleeve. The shoulder  48  may have inner and outer faces  50 , 52 . The sleeve outer surface  42  of the sleeve  40  may have a circumferential groove  54 . A resilient ring  56  may be disposed in the circumferential groove  54  of the sleeve outer surface  42 . The resilient ring  56  and circumferential groove  54  may be configured and dimensioned to allow the resilient ring to be retained in the circumferential groove while allowing the resilient ring to expand and compress as needed in manner described below. The resilient ring  56  may have an outer diameter  58 . The sleeve outer surface  42  may cylindrical and aside from the circumferential groove  54  may be devoid of other surface features. The resilient ring  56  may be an o-ring. The resilient ring  56  may be configured to be compressible in the circumferential groove  54  in a manner such that the resilient ring outer diameter  58  may be compressed to a resilient ring compression diameter sufficient to enable the sleeve  40  to be inserted in the bore  22  of the rotation surface  16 . The resilient ring  56  may be configured to be expandable in the circumferential groove  54  such that the resilient ring outer diameter  58  may expand to a resilient ring expansion diameter greater than the inner surface diameter  24  of the bore  22  of the rotation surface  16  when the resilient ring  56  is unconstrained about the resilient ring outer diameter, for instance, when the resilient ring passes through the bore of the rotation surface and clears the effective axial length of the bore of the rotation surface. Referring to  FIGS. 4 and 5 , the inner face  52  of the shoulder  48  of the sleeve  40  may positioned to abut a face of the rotation surface  16  when inserted in the bore  22  of the rotation surface. Accordingly, the circumferential groove  54  of the sleeve outer surface  42  may be spaced from the shoulder inner face  52  at a distance sufficient to enable the resilient ring outer diameter  58  to expand to the expansion diameter when the sleeve  40  is inserted in the bore  22  of the rotation surface  16  and the shoulder inner face  52  abuts the rotation surface. In another example, a flinger structure or seal disk (not shown) may form the face of the rotation surface  16  and/or otherwise be disposed between the rotation surface and the shoulder inner face  52 . In this configuration, the circumferential groove  54  of the sleeve outer surface  42  may be spaced from the inner face  52  of the shoulder  48  at a distance sufficient to enable the resilient ring outer diameter  58  to expand to the expansion diameter when the sleeve is inserted in the bore of the rotation surface and the shoulder inner face is adjacent the rotation surface and abutting the flinger structure or seal disk. In another example, as best shown in  FIG. 5 , the rotation surface  16  has an axial inner edge with an edge break, and the circumferential groove  54  of the sleeve outer surface  42  is spaced from the inner face  52  of the shoulder  48  at a distance sufficient to enable the resilient ring outer diameter  58  to expand to the expansion diameter adjacent the edge break when the sleeve  40  is inserted in the bore of the rotation surface and the shoulder inner face  52  is adjacent or abuts the rotation surface  16 , as the case may be depending upon whether the rotation surface has an intermediate structure. In the last example, the circumferential groove  54  of the sleeve outer surface  42  is spaced from the inner face  52  of the shoulder  48  at a distance sufficient to enable the resilient ring  56  to clear the effective axial length of the rotation surface  16 . Where no edge break condition is provided on the innermost axial edge of the rotation surface, the circumferential groove  54  of the sleeve outer surface  42  may be spaced from the inner face  52  of the shoulder  46  at a distance sufficient to enable the resilient ring  56  to clear the axial length of the rotation surface  16  and expand to the expansion diameter. In each of the examples above, the shoulder  48  may be pressed against the face of the rotation surface (or intermediate structure) to provide indication that the resilient ring has cleared the axial length of the rotation surface and has thus expanded to the resilient ring expansion diameter. The sleeve may also be dimensioned to allow some axial play between the shoulder and the face of the rotation surface (or intermediate structure) with the resilient ring cleared from the axial length of the rotation surface and at the resilient ring expansion diameter, for instance, to allow the sleeve to be grasped by the shoulder  48  and extracted from the bore  22  of the rotation surface. The resilient ring  56  may be configured to be sufficiently deformable such that the resilient ring outer diameter  58  may be compressed to an extraction diameter to enable the sleeve to be removed from the bore of the rotation surface the bearing with minimal force, as may be required during the assembly process. Accordingly, the resilient ring  56  may be configured so that the sleeve  40  is removably insertable in the bore of the rotation surface  10 . The outer surface of the sleeve may have a close running fit (or with more accuracy a precision running fit) with the bore of the rotation surface thus allowing the sleeve to have a relatively small amount of clearance with the bore of the rotation surface with moderate requirements for accuracy. The outer surface of the sleeve may have a sliding fit (or with more accuracy a close sliding fit) with the bore of the rotation surface thus allowing the sleeve to have a relatively minimal amount of clearance with the bore of the rotation surface with higher requirements for accuracy. The resilient ring may deform to the compression and extraction diameter without otherwise changing the nature of the fit between the sleeve and the bore of the rotation surface. 
     Referring to  FIG. 6 , with the sleeve  40  installed in the respective bore  22  of the rotation surface  16 , the sleeve forms a mounting surface for the rig fork or yoke  70  of the caster  10 . In one example where first and second sleeves  40  are inserted in the respective bores  22  of the inner races  34  of the bearings  30  on axial opposite sides of the hub  14  of the wheel, the sleeves may abut against each other inside the hub of the wheel. The caster forks  70  may then be tightened against the sleeves  40  with an axle pin  80  and fastener  82 . The caster forks  70  may bear against the shoulders  48  of the respective sleeves  40  which in turn loads the faces of the inner races  34  of the bearings  30 . The wheel bearing  30  can then spin freely around the sleeves  40  without binding. Accordingly, each sleeve  40  is adapted and configured to receive an axle pin  80  of the caster to secure the respective fork  70  against the shoulder  48  of the sleeve  40 . 
     In use, the sleeve  40  may be pushed into the bore  22  of the inner race  34  of the bearing  30  disposed in the hub  14  of the wheel  12 . As the case may be, a second sleeve may be pushed into the bore of the inner race of a second bearing disposed on an axially opposite side of the hub of the wheel. The sleeve  40  may retained in the bore  22  of the inner race  34  of the bearing  30  by the resilient ring  56 , e.g., an o-ring. The resilient ring  56  may be arranged on the sleeve  40  such that its outer diameter  58  compresses to a compression diameter as the sleeve is being inserted into and slides through the bore  22  of the inner race  34  of the bearing  30  disposed in the hub  14  of the wheel  12 . The resilient ring  56  may be arranged on the sleeve  40  to return to its full or expansion diameter  58  once the resilient ring  58  passes through the bore  22  of the inner race  34  past the effective axial length of the bore of the inner race of the bearing. The result is that the sleeve  40  “snaps” into place within the bore  22  of the inner race  34  of the bearing  30  and is retained therein. This eliminates the need to use an external device, for instance, a tie or zip tie, to keep the sleeve  40  with the wheel  12  during the manufacturing and assembly process. The expansion of the resilient ring  56  is sufficient to retain the sleeve  40  in the bore  22  of inner race  34  of the bearing  30 . However, the resilient ring  56  is sufficiently deformable to allow the resilient ring outer diameter  58  to compress to an extraction diameter to enable the sleeve  40  to be removed from the bore  22  of the inner race  34  of the bearing  30  with minimal force, as may be required during the assembly process. 
     Further embodiments can be envisioned by one of ordinary skill in the art after reading this disclosure. In other embodiments, combinations or sub-combinations of the above-disclosed invention can be advantageously made. The example arrangements of components are shown for purposes of illustration and it should be understood that combinations, additions, re-arrangements, and the like are contemplated in alternative embodiments of the present invention. Thus, various modifications and changes may be made thereunto without departing from the broader spirit and scope of the invention as set forth in the claims and that the invention is intended to cover all modifications and equivalents within the scope of the following claims.