Appeal 2007-0387
Application 09/756,688
1 FINDINGS OF FACT
2 Lovell discloses a propeller shaft bearing for a boat or other marine
3 propulsion systems. Specifically, Lovell has a casing 10 for receiving a propeller
4 shaft 16 therein with a lower end of the casing including a bearing 40 and a grease
5 seal 75. The grease seal prevents the accumulation of mud. See col. 4, l. 69.
6 Lovell further provides a rear end cap 62. The invention of Lovell comprises a
7 well known cutlass bearing which consists of a bronze outer shell 42 and a hard
8 rubber insert 44 bonded to the inside of the outer shell 42. The inner shell has a
9 series of longitudinal ribs 46 which define longitudinal channels 48 therebetween.
10 The cutlass bearing 40 is both water lubricated and cleansed by water which flows
11 longitudinally therethrough after the water is scooped by a pair of water scoops 84
12 located on opposite sites of the propeller shaft.
13 It is our further finding that Appellant’s Specification (3:4-4:10)
14 discusses the prior art in the following explanation:
15
16 The use of a long propeller shaft and casing necessitates the provision
17 of bearings or bushings at the ends of the casing, including the end
18 closest to the propeller. While in use, the propeller and adjacent
19 bearing will be submerged for the vast majority of operation. In the
20 prior art, bushings made from brass or the like have heretofore been
21 most commonly used, due to the substantial water exposure.
22 Unfortunately, submerged roller or ball bearings which are not
23 adequately protected from the water rapidly lose grease or other
24 lubricants, thereby leading to early bearing failure. In addition,
25 bushings may be manufactured to add very little extra size to the
26 casing beyond the diameter of the rotating shaft, while bearings tend
27 to be much larger and therefore more prominent. Adjacent the
28 propeller, a prominent bearing translates into significant drag through
29 the water and undesirable mass adjacent the propeller. Because
30 bearings are intrinsically larger than bushings, where they have been
31 used there has been an effort to minimize the package for the bearing,
3
Page: Previous 1 2 3 4 5 6 7 8 Next
Last modified: September 9, 2013