Appeal 2007-1459
Application 10/204,413
The third issue is whether Litvin discloses a hypoid gear.
The fourth issue is whether Wildhaber discloses an involute helicoid.
FINDINGS OF FACT
Appellant’s Specification discloses that a hypoid gear is a pair of
gears whose axes do not intersect and are not parallel with each other
(Specification 2).
The Specification equates the ratio of angular velocity with the gear
ratio (Specification 69, l. 5). The specification repeatedly refers to “gear
ratio i0” (Specification 67, 68, and 69).
The Specification also discloses that the ratio of the offset E and the
radius R20 (E/R20) is a design parameter for a hypoid gear (Specification 67).
Figure 22 depicts both E and R20. Claim 10 is an original claim and recites
that E/R20 is larger than 0.25.
An involute helicoid is a known geometric curve which is traced by a
point on a straight line which rolls without slipping on the circle and forms a
helical rather than circular arc (Honda Decl., paragraph 4; Litvin, col. 3, l.
48).
Litvin discloses a gear in which the tooth surface on one gear of a pair
of gears is an involute helicoid (Litvin, col. 3, ll. 47-52). The teeth on the
gear which is an involute helicoid has a driving surface 59 and a coast
surface 63 (Litvin, col. 4, ll. 1-3) with base circles that differ at the drive side
and the coast side. Litvin discloses that the axes of the gears can be
intersecting or crossed or nonintersecting (Litvin, col. 3, ll. 56-58). Litvin
does not disclose or suggest a ratio of the offset E and the radius R20 being
4
Page: Previous 1 2 3 4 5 6 7 8 9 Next
Last modified: September 9, 2013