Appeal No. 2002-0500 Page 15
Application No. 09/258,320
sleeve "comprises an outer cylindrical layer 34a having a relatively great length and two
inner cylindrical layers 34b each having relatively small lengths wherein one of inner
cylindrical layers 34b is disposed on the inner wall of the upper end portion of the outer
cylindrical layer 34a and the other one is disposed on the inner wall of the lower end
portion of the outer cylindrical layer 34a." Id. at ll. 42-49. Figure 1 of the reference
shows that the boss 58 is positioned above a space between the oil-impregnated
sleeve 34 and the rotating shaft 56. Because the boss 58 is positioned above the
space, fig. 1, it necessarily would block any oil splashed from the space.
Figure 1 also shows the oil seal 45 mentioned by the appellants. More
specifically, "[a] ring-shaped oil seal 45 made of felt is disposed on the oil-impregnated
sleeve bearing 34 in such a manner that the lower face of the oil seal 45 is in contact
with the upper face of the oil-impregnated sleeve bearing 34, that is, with the upper
faces of the outer and inner cylindrical layers 34a and 4b." Col. 4, ll. 34-39. Although
the seal is designed to absorb oil, col. 6, l. 18, we have no reason to believe that it is
free from all imperfection. Furthermore, one of ordinary skill in the art would know that
seals deteriorate over time. Such imperfection or deterioration would eventually allow
oil to leak therethrough. Because the boss 58 is positioned above the oil seal 45, fig. 1,
however, we find that any such leakage would be blocked by the boss. Therefore, we
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