Abstract:
A compact lubricant reservoir for a bearing housing is provided whereby visual inspection of the reservoir indicates the level of lubricant reserve.

Description:
FIELD OF THE INVENTION 
     The present invention generally relates to the lubrication of bearings, and in particular, to indicating lubricant reservoirs for bearing housings of the pillow block or flange type. 
     BACKGROUND OF THE INVENTION 
     It is believed that as many as one-third of all bearing failures are the result of improper lubrication. Improper lubrication is particularly prevalent in the case of housing mounted bearings that are intended to be manually re-lubricated by means of a grease fitting. The present invention provides for a lubricant reservoir and a visual indicator for the lubricant level therein for use with pillow block or flange type bearing housings. 
     SUMMARY OF THE INVENTION 
     The present invention provides a bearing housing having a compact lubricant reservoir in communication with the bearing contained by the housing, whereby visual inspection of the reservoir indicates the level of lubricant reserve. 
     In one embodiment of the invention, a concave recess is provided in the surface of the housing, with a communicating passageway between the recess and the housed bearing. An invertible diaphragm is sealed to the annular surface of the concave recess. The invertible diaphragm has an at least partially convex lower surface facing the concave recess, with the lower surface extending into the concave recess in the substantial absence of lubricant (initial conformation). 
     In one embodiment, contoured thickness of the diaphragm is used to return the diaphragm to the initial conformation. In another embodiment, foam rubber located between the diaphragm and a metal shield supplies the restoring force to return the diaphragm to the initial conformation. A projection extending from the back of the diaphragm provides a simple and direct measure of the lubricant remaining in the reservoir. 
     It is an object of the present invention, therefore, to provide a compact and low profile lubricant reservoir for use with a bearing housing. 
     It is an object of at least one embodiment of the invention to provide a lubricant reservoir for a bearing housing having a visual indication as to the level of lubrication residing therein. 
     It is object of at least one embodiment of the invention to provide a compact lubricant reservoir mountable directly into the surface of a bearing housing. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The above as well as other objects of the invention will become more apparent from the following detailed description of the preferred embodiments of the invention, when taken together with the accompanying drawings, wherein like numerals refer to like parts, in which: 
     FIG. 1A is a cross-sectional view of a reservoir in the initial (unfilled) conformation according to one embodiment of the instant invention, mounted in a bearing housing (shown in partial sectional view). 
     FIG. 1B is a cross-sectional view of the reservoir shown in FIG. 1A, shown in the filled conformation. 
     FIG. 2 is a perspective view of a pillow block type bearing housing (sans bearing) with the reservoir shown in FIG. 1B mounted in one preferred location. 
     FIG. 3A is a cross-sectional view of a flush mounted reservoir according to another embodiment of the invention. 
     FIG. 3B is a cross-sectional view of a flush mounted reservoir having a diaphragm with integral spring rings for returning the diaphragm to the initial conformation. 
     FIG. 3C is a cross-sectional view of a flush mounted reservoir having a diaphragm with notched integral spring rings for returning the diaphragm to the initial conformation. 
     FIG. 4A is a cross-sectional view of a canister-mounted reservoir having a convoluted diaphragm, shown in the initial conformation. 
     FIG. 4B is a cross-sectional view of a canister-mounted reservoir having a convoluted diaphragm, shown in the filled conformation. 
     FIG. 5 is a perspective view of a canister reservoir as shown in FIG.  4 B. 
     FIG. 6 is a cross-sectional view of a flush mounted reservoir having a convoluted diaphragm, shown in the initial conformation. 
     FIG. 7A is a cross-sectional exploded view of a flush mounted reservoir according to an embodiment of the invention. 
     FIG. 7B is a cross-sectional view of the flush mounted reservoir of FIG. 7A, shown in the filled conformation. 
     FIG. 7C is a cross-sectional view of an alternative embodiment to that of FIG. 7B, wherein a plurality of projections act as indicators of the fill state. 
     FIG. 8A is a cross-sectional exploded view of a flush mounted reservoir, according to another embodiment of the invention. 
     FIG. 8B is a cross-sectional view of the assembled flush mounted reservoir of FIG. 8A, shown in the initial conformation. 
     FIG. 9A is a cross-sectional exploded view of a flush mounted reservoir, according to one embodiment of the invention. 
     FIG. 9B is a cross-sectional view of the assembled flush mounted reservoir of FIG. 9A, shown in the initial conformation. 
     FIG. 9C is a cross-sectional view of domed diaphragm according to one embodiment of the invention. 
     FIG. 10A is a cross-sectional exploded view of a flush mounted reservoir, according to one embodiment of the invention. 
     FIG. 10B is a cross-sectional view of the assembled flush mounted reservoir of FIG. 10A, shown in the initial conformation. 
     FIG. 11A is a cross-sectional view of a flush mounted reservoir according to another embodiment of the invention, shown in the initial conformation. 
     FIG. 11B is a cross-sectional view of the flush mounted reservoir shown in FIG. 11A, shown in a partially filled conformation. 
     FIG. 12A is a cross-sectional view of the flush mounted reservoir according to another embodiment of the invention, shown in the initial conformation. 
     FIG. 12B is a cross-sectional view of the flush mounted reservoir shown in FIG. 12A, shown in the filled conformation. 
     FIG. 13A is a cross-sectional view of the flush mounted reservoir according to another embodiment of the invention, shown in the initial conformation. 
     FIG. 13B is a cross-sectional view of the flush mounted reservoir shown in FIG. 12A, shown in the filled conformation. 
    
    
     DESCRIPTION OF THE INVENTION 
     Turning now to FIG. 1A, a cross-sectional view of a reservoir  1  according to one embodiment of the invention is shown. Bearing housing  2  (partially shown) comprises recess  4 , into which diaphragm  6  projects. Indicator  8  projects from the backside of diaphragm  6 , and extends into the proximity of passageway  10  in the protective shield  12 . The protective shield  12  traps and seals the annular periphery  14  of diaphragm  6  against the annular wall  16  of recess  4 . In FIG. 1B, the recess  4  has been filled with lubricant  18  by means of conduit  20 , which communicates to the housed bearing and grease fitting (not shown). Indicator  8  protrudes from the passageway  10  to give a visual indication of the fill level. 
     Foam rubber  250  located between diaphragm  6  and shield  12  supplies the restoring force to return the diaphragm  6  to the initial conformation. 
     FIG. 2 illustrates one location in which the reservoir  3  may be placed on the exterior surface of a pillow block type bearing housing  2 . While the reservoir  3  may be placed in any location, it is preferred that it be placed so as to give the maintenance worker greasing the bearing a ready view of its condition. 
     Turning now to FIGS. 3A-C, an embodiment of the invention is shown wherein the recess  4  is extended into the housing  2  so that flush mounting of shield  22  is possible. In FIG. 3B, annular rings  24 ,  26  projecting from the backside of the diaphragm  6  serve to return the diaphragm to the initial conformation. In FIG. 3C, the annular rings  28 ,  30  are notched to reduce the spring rate. 
     An alternative embodiment of the invention is illustrated in FIGS. 4A-5, useful where the bearing housing is not thick enough to accommodate a recess of sufficient depth, or for retrofit of existing bearings. In FIG. 4A, a reservoir in the initial conformation is shown generally as numeral  50 . The reservoir comprises cylinder body  52 , having a fitting  55  for attachment to a bearing housing. The fitting  55  would typically be threaded with standard pipe threads, but may also provide for a press fit into a hole provided in the bearing housing (not shown), or for welding, brazing, or adhesive attachment thereto. The diaphragm  54  is shown to be a convoluted tube having convolutions  56 , an annular sealing section  58 , and an indicator  60  extending from the rear surface thereof A sealing cup  62 , pressure seals the diaphragm  54  annular sealing section  58  of the cylinder body  52 . In FIG. 4B, the reservoir  50  is shown in the filled conformation, with grease  65  supplied through passageway  64 , and indicator  60  extending through sealing cup  62  to indicate that the reservoir is filled. FIG. 5 is a perspective view of the reservoir of FIG. 4B, with wrench flat  66 . Where the housing is sufficiently thick, the reservoir  51  may be entirely incorporated in the housing wall, as shown in FIG. 6, wherein the cylinder body is replaced by the recess  68 . 
     In FIGS. 7A and 7B, diaphragm  80 , is sealed from above by domed shield  82 , which has passageway  84 , though which indicator  86  projects when reservoir  88  is in the filled conformation, as shown in FIG.  7 B. Alternatively, the shield may comprise a transparent polymeric or elastomeric material for viewing (not shown). If the shield comprises a translucent material, the size of the contact area of the diaphragm  80  against the underside of the shield  82  would thereby indicate the filled or partially filled conformation. In FIG. 7C, a plurality of indicators  86  are used to indicate the fill status of the reservoir  88 . A similar reservoir  89  is shown in FIGS. 8A and 8B, wherein diaphragm  90  is sealed from above by ring  92 . 
     Turning now to FIG. 9A, a directly indicating reservoir  100  is shown in an exploded view to comprise recess  102 , conduit  104 , clamp/seal ring  106 , and diaphragm  108 . Diaphragm  108  comprises a domed section  110  extending towards and into recess  102 , and annular ring  112  for sealing against the recess wall  114 . The assembled reservoir is shown in FIG. 9B, in the initial conformation. In FIG. 9C, ribs  109  extending from the domed section  110  are used to produce an asymmetric stiffness, so that the domed section  100  is not bi-stable. 
     In another embodiment, shown in FIGS. 10A and 10B, a reservoir  140  comprising a one-piece dished diaphragm  142  is press fit into a recess  132  within bearing housing  130 . The recess  132  preferably comprises an undercut  134  for capturing a lip  136  on the exterior annular sealing ring  138  of diaphragm  142 . Optional wire element  144  may be used for stiffening the sealing ring  138 . 
     In FIGS. 11A and 11B a reservoir  150  according to another embodiment of the invention is shown in the initial and filled conformations respectively. Diaphragm  152  comprises a hollow flexible tube extending into recess  154 . Foam  156  within diaphragm  152  serves to provide a restoring force to return the reservoir to the initial conformation. A bulge  160  of foam  156  within passageway  164  in protective seal cap  166  serves to indicate the conformational state of the reservoir. 
     In FIGS. 12A and 12B a reservoir  200  according to another embodiment of the invention is shown in the initial and filled conformations respectively. Foam element.  206  is adhesively bonded to the lower surface of shield  222 , having passageway  214 . Shield  222  forms a cup that press fits into the cylindrical recess  210  of housing  202 , so as to produce an annular seal. In FIG. 12B, foam element  206  is compressed by the presence of lubricant  216 , delivered to the cylindrical recess  210  by means of conduit  212 . A bulge  208  of in the outer surface of foam element  206  into passageway  214  in shield  222  serves to indicate the conformational state of the reservoir. 
     In FIGS. 13A and 13B a reservoir  201  according to yet another embodiment of the invention is shown in the initial and filled conformations respectively. Foam element  236  is adhesively bonded to the lower surface of shield  222 , having passageway  214 . Shield  222  forms a cup that press fits into the cylindrical recess  210  of housing  202 , so as to produce an annular seal. An optional rigid plate  226  is bonded to the inner surface of foam element  236 . A circular (or other closed shape) incision  224  extends in from the outer surface of foam element  236 , but does not penetrate it completely. In FIG. 12B, foam element  236  is compressed by the presence of lubricant  216 , delivered to the cavity  210  by means of conduit  212 . Bulge  230  of in the outer surface of foam element  236  into passageway  214  in shield  222  serves to indicate the conformational state of the reservoir. Incision  224  (which may optionally be molded into foam element  236 ) serves to allow bulge  230  to extend further outwards to give a more reliable indication of the conformational state. 
     Diaphragm materials used in the various embodiments may comprise any material sufficient flexible and resistant to the lubricants used in bearings. Such materials may include elastomers taken from the non-exclusive list consisting of polychloroprene, poly (butadiene-styrene), poly (styrene-butadiene-styrene), poly (ethylene-propylene), silicone, fluoroelastomer, chlorosulfonated polyethelene elastomer, perflouroelastomer, acrylic elastomers, polyurethane, polyisoprene, and/or polymers taken from the non-exclusive list consisting of PTFE, ionomer, polyaramid and polyamide. Foam for use in the various embodiments of the invention may comprise any polymer or elastomer of sufficient compression set and heat resistance to return the diaphragm substantially to the initial conformation, and may comprise any of the polymers or elastomers listed above. An open cell foam is preferred, which would typically be coated at least on its inner surface so as to provide a barrier to the passage of lubricant. Foams having closed cells and mixtures of closed and open cells may also be used, especially where higher spring rates are desired. Shield materials for use with the present invention are preferably comprised of a metal such as aluminum, magnesium, copper, brass, and steel, but may also be comprised of a stiff polymer or elastomer. 
     Although only a few exemplary embodiments of this invention have been described in detail above, those skilled in the art will readily appreciate that many modifications are possible in the exemplary embodiments without materially departing from the novel teachings and advantages of this invention. Accordingly, all such modifications are intended to be included within the scope of this invention as defined in the following claims. In the claims, means-plus-function clauses are intended to cover the structures described herein as performing the recited function and not only structural equivalents, but also equivalent structures.