Appeal No. 95-4863
Application 07/865,993
This is a decision on the appeal under 35 U.S.C. § 134
from the examiner's final rejection of claims 1, 2 and 4, which
constituted all the claims remaining in the application. An
amendment after final rejection was filed on November 18, 1994
and was entered by the examiner. This amendment cancelled claim
4. Therefore, this appeal involves only claims 1 and 2.
The claimed invention pertains to a piezoelectric sensor
for measuring pressure in an internal combustion engine.
Representative claim 1 is reproduced as follows:
1. A piezoelectric sensor for an internal combustion
engine having a cylinder, comprising:
a main body adapted to be attached to the cylinder
and defining an axially extending hole therewithin;
a diaphragm attached to one end of said main body for
closing said hole; and
a piezoelectric element in the form of a circular or
polygonal disc whose major surface is in the x-y plane disposed
within said hole so that the pressure within said cylinder is
transmitted transverse to the x-y plane of said piezoelectric
element disc through said diaphragm,
said piezoelectric element disc having a thickness in
the range of 0.3-1.5 mm and being formed of a single crystal
piezoelectric ceramic having a Curie temperature higher than the
normal operating temperature of the engine and not less than
500EC and being polarized such that the direction of the
polarization is oriented at an angle of 20E or less with respect
to said disc x-y plane.
The examiner relies on the following references:
Epstein 3,714,476 Jan. 30, 1973
2
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