Appeal 2007-2358
Reexamination Control No. 90/006,888
material for the inner layer should have a large modulus of elasticity and a
small coefficient of friction with respect to the glass fibers. (Id. at 2:47-49.)
According to Oestreich, polystyrene is a "particularly good" material for the
inner layer, but fluoropolymers are also suitable, including "Teflon PFA sold
by DuPont." (Id. at 2:53–58.)
The protective casing described by Oestreich meets every limitation
recited in claim 1. First, it is "relatively flexible" due to the plastics from
which it is made. Second, it is a two-layer casing that has a low friction
inner surface relative to the optic fiber or cable. The inner surface is
described in embodiments as fluoropolymers, including a TeflonŽ, in order
to provide a low coefficient of friction with respect to the optical fiber or
optical cable. The low friction coefficient and the ratio (2:1 or 3:1) of the
inner diameter of the casing to the fiber or cable indicate that the inner
surface has the properties required to perform the "slidably receiving" and
"low friction placement of the cable therewithin" functions required of the
tube of Applicants' claim 1. Third, the outer casing, which is described, in
embodiments, as polyethylene, is said to protect against buckling and
lengthwise compression. Thus the Oestreich protective casing fairly
maintains the structural integrity of the tube, thereby providing a protective
housing for the optical fiber or optical cable, as disclosed.
Dura Line argues that Oestreich "is directed to an entirely
distinguishable invention" (Br. at 7), namely, a "'buffer tube' component of
an optical fiber cable used to house individual optical fibers" (id.; emphasis
original, but not all emphasis reproduced). Dura Line does not cite any
evidence in support of its argument. The argument is not persuasive because
it does not explain what limitations of the claimed subject matter are not met
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