Appeal No. 2000-0008 Page 4
Application No. 08/842,990
the hollow stock is reduced but the internal diameter is not
substantially changed.
Bononi discloses a cold forging method in which both
inside and outside diameters are reduced (Col. 3, lines 46 to
53; Col. 4, lines 25 to 26).
U.S. Steel is silent about the reduction of wall
thickness in cold forging of a hollow stock.
Hotta discloses a gear shaft manufacturing method in
which a mandrel is inserted into several successive hollow
shaft workpieces. In one step of the process a mandrel 3d is
inserted into the shaft hole of workpiece M2 and the lower
part outer diameter is reduced to a smaller diameter by
extrusion and M3 is formed. The inner diameter of M3 appears
unchanged. (See Figure 1).
The examiner states:
It would have been obvious to one having
ordinary skill in the art at the time the
invention was made to employ a mandrel, as
shown by Hotta, in Figure 10 extrusion of
Bononi et al. in order to obtain controlled
wall thickness and inner diameter merely as
the utilization of knowledge clearly
available in the art for producing desired
characteristics in the product, and not a
patentable distinction absent a disclosure
of criticality in the solution of stated
Page: Previous 1 2 3 4 5 6 7 8 Next
Last modified: November 3, 2007