Appeal No. 2006-1220
Application No. 10/457,960
skill in the art. In re Kahn, 441 F.3d 977, 987-88, 78 USPQ2d 1329, 1336 (Fed.
Cir. 2006).
In this case, the Ramer and Callahan devices are not nearly so different as
the appellant would have us believe. They share more in common with one
another than their function to lift a load, as the appellant contends on page 5 of the
brief. Specifically, both references utilize lifting mechanisms comprising flexible
ties (cables or straps) that are wound and unwound about sheaves or winches and
incorporate transmission arrangements that ensure that the ties are wound or
unwound in unison to raise or lower the lift platform in a level manner. Ramer
uses a fluid cylinder actuated crosshead carrying sheaves about which each of the
cables extends to actuate the cables to lift the platform and Callahan uses two
parallel shafts each having two winches mounted thereon, the shafts being rotated
in unison in opposite directions by means of a motor and appropriate transmission,
to wind or unwind the straps to raise or lower the platform.
As evidenced by the teachings of Ramer and Callahan, one of ordinary skill
in the portable lift art at the time of appellant’s invention would have possessed the
knowledge that linearly actuated crossheads in conjunction with sheaves and
rotated shafts with winches are alternate equivalent arrangements for transferring
lifting or lowering motion from a motor to flexible ties of a hoisting mechanism in
unison so as to raise the lifting platform in a level orientation. As such, the
selection of either arrangement would have been obvious to a skilled artisan faced
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