Appeal No. 1999-1170 Page 4
Application No. 08/801,872
having a radial spring rate whose magnitude, when expressed in lb/in, is in
the range of between one half and three times said magnitude of design
torque level [of the coupling] expressed in lb-in, said elastomer member
being bonded to one of said housing and said hub and having frictional
engagement with the other of said housing and said hub to transmit torsional
load therebetween; said radially soft elastomer member being axially
precompressed between said housing and said hub increasing frictional
engagement between with the other of said housing and said hub and
producing additional radial softening of said elastomer . . . .
This claim stands rejected as being unpatentable over the acknowledged prior art
illustrated in Figure 3 of the appellant’s drawings in view of Eksergian. It is the examiner’s
position that all of the subject matter recited in claim 1 is disclosed in Figure 3 except for
the recited spring rate magnitude and the requirement that the elastomer member be
bonded to one of the power transmitting elements and in frictional engagement with the
other. As to the required spring rate magnitude, the examiner is of the view that this
feature would have been a matter of obvious engineering design to one of ordinary skill in
the art, who is expected to routinely experiment with result effective variables so as to
ascertain the optimum or workable ranges for a particular use (Answer, sentence bridging
pages 3 and 4). With regard to the manner in which the elastomer members interface with
the drive and driven shafts, the examiner looks to Eksergian, which he describes as
teaching that couplings can utilize bonded or frictional interfaces or combinations thereof
to transmit power, from which he concludes that it would have been obvious to modify the
device shown in Figure 3 so that the elastomer is bonded to one of the drive elements and
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