DETAILED ACTION
Notice of Pre-AIA or AIA Status
The present application, filed on or after March 16, 2013, is being examined under the first inventor to file provisions of the AIA .
Continued Examination Under 37 CFR 1.114
A request for continued examination under 37 CFR 1.114, including the fee set forth in 37 CFR 1.17(e), was filed in this application after final rejection. Since this application is eligible for continued examination under 37 CFR 1.114, and the fee set forth in 37 CFR 1.17(e) has been timely paid, the finality of the previous Office action has been withdrawn pursuant to 37 CFR 1.114. Applicant's submission filed on 19 December 2025 has been entered.
Status
This Non-Final Office Action is in response to the request for continued examination dated 21 January 2026 (hereinafter “Reply”).
Claim(s) 1-20 is/are presently pending.
Response to Arguments
Regarding the rejection of claim(s) 1-5, 8-12, 15 under 35 U.S.C. 103 as being unpatentable over Leblanc in view of Setter, the applicant(s) submit the following remark(s)/argument(s):
(A) At page 7 of the submitted Reply:
The cited art fails to teach or suggest the following feature(s) of claims 1 and 8: the groove has an axial groove width greater than an axial ring width of the piston ring, such that the operating pressure moves the piston ring in the groove axially toward an axially upstream wall of the groove. Specifically, Leblanc fails to teach the axial groove width is oversized to allow an axial shift of the piston ring in the groove.
In reply, the Office respectfully considers this argument partly persuasive. The cited art teaches the groove has an axial groove width greater than an axial ring width of the piston ring (e.g. see Fig. 3 of Leblanc that shows the piston ring 86 has a width smaller than the groove 84 because the piston ring is positioned within the groove). However, the cited art fails to teach the axial groove width is large enough to achieve the claimed result of the piston ring moves axially under operating pressure (e.g. see Fig. 3 of Leblanc which shows there is no space between the piston ring 86 and the groove at axially upstream and downstream ends of the piston ring). Therefore, the rejection(s) is/are withdrawn. However, upon further consideration a new ground(s) of rejection is made under 35 U.S.C. 103.
Regarding the rejection of claim(s) 16-18 under 35 U.S.C. 103 as being unpatentable over Gardiner in view of Setter, the applicant(s) submit the following remark(s)/argument(s):
(A) At page 8 of the submitted Reply:
The cited art fails to teach or suggest the following feature(s) of claim 16: in operation the piston ring is moved axially in the groove toward the upstream axial face of the case element groove. Specifically, Gardiner teaches the pressure differential moves element 12 toward element 11 and fails to teach the piston ring 30 is moved axially in the groove.
In reply, the Office respectfully considers this argument persuasive. Therefore, the rejection(s) is/are withdrawn. However, upon further consideration a new ground(s) of rejection is made under 35 U.S.C. 103.
Claim Rejections - 35 USC § 103
The following is a quotation of 35 U.S.C. 103 which forms the basis for all obviousness rejections set forth in this Office action:
A patent for a claimed invention may not be obtained, notwithstanding that the claimed invention is not identically disclosed as set forth in section 102, if the differences between the claimed invention and the prior art are such that the claimed invention as a whole would have been obvious before the effective filing date of the claimed invention to a person having ordinary skill in the art to which the claimed invention pertains. Patentability shall not be negated by the manner in which the invention was made.
This application currently names joint inventors. In considering patentability of the claims the examiner presumes that the subject matter of the various claims was commonly owned as of the effective filing date of the claimed invention(s) absent any evidence to the contrary. Applicant is advised of the obligation under 37 CFR 1.56 to point out the inventor and effective filing dates of each claim that was not commonly owned as of the effective filing date of the later invention in order for the examiner to consider the applicability of 35 U.S.C. 102(b)(2)(C) for any potential 35 U.S.C. 102(a)(2) prior art against the later invention.
Claim(s) 1-5, 8-12, and 15 is/are rejected under 35 U.S.C. 103 as being unpatentable over U.S. Patent No. 10,253,644 to LeBlanc et al. (hereinafter “LEBLANC”) in view of United States Patent Application Publication No. 2024/0167389 to Alecu et al. (hereinafter “ALECU”) and further in view of U.S. Patent No. 1,363,281 to Setter (hereinafter “SETTER”).
(A) Regarding Claim 1:
LEBLANC teaches:
A piston ring seal arrangement of a gas turbine engine, comprising:
a piston ring (86, Fig. 3) having a first axially-facing side (facing upstream) and a second axially-facing side (facing downstream) opposite the first axially facing side
a mating component having a groove (84) into which the piston ring is installed; and
wherein the piston ring is installed in the groove such that an operating pressure acting on the piston ring is greater at the second axially-facing side (i.e. the downstream facing side) than at the first axially-facing side (i.e. the upstream facing side)(see col. 1, ll. 8-16: seal to reduce leakage),
wherein the groove has an axial groove width greater than an axial ring width of the piston ring (see Fig. 3, wherein the piston ring is entirely positioned within the groove).
However, the difference between LEBLANC and the claimed invention is that LEBLANC does not explicitly teach the operating pressure moves the piston ring in the groove axially toward an axially upstream wall of the groove.
ALECU teaches:
A groove (48, Fig. 5A) has an axial groove width (W) greater than an axial ring width (RW) of a piston ring (50), such that an operating pressure (para. 0035: P2>P1) moves the piston ring in the groove axially toward an axially upstream wall of the groove (para. 0036: the higher pressure P2 in the SRC is intended to bias the piston ring seal 50 against the first lateral surface 52 to produce the seal and para. 0033: the width of the piston seal ring 50 is less than the width of the seal groove (i.e., W>RW) to permit axial movement of the piston axial seal within the seal groove).
Thus, both LEBLANC and ALECU teach a seal assembly using a piston ring positioned within a groove. Therefore, it would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to substitute the piston and groove seal arrangement of ALECU for the piston and groove seal arrangement of LEBLANC to achieve the predictable result of providing a seal between two areas of different pressure (ALECU para. 0036). See MPEP 2141(III)).
Furthermore, the Applicant has not disclosed any unexpected results to suggest that having the axial groove width so large that the piston ring moves in the groove under operating pressure provides an advantage, solves a stated problem, or is used for a particular purpose beyond the fact that the groove must be large enough to fit the piston ring and allow for temperature fluctuations in the materials, wherein the operating pressure inherently applies a force to the piston ring in the upstream direction. Furthermore, it appears that the piston and groove seal of LEBLANC would perform equally well with a difference in widths that allows for movement of the piston during an applied operating pressure because the function of the seal, i.e. to bias against the upstream face of the groove under an operating pressure, remains the same. Therefore, it would have been an obvious matter of design choice to modify the groove and/or piston widths to obtain the claimed invention and thereby achieve the predictable result of sealing between two different areas of pressure (ALECU para. 0036).
However, the difference between modified LEBLANC and the claimed invention is that modified LEBLANC does not explicitly teach the piston ring having a circumferentially split ring configuration having a first circumferential end circumferentially over lapping a second circumferential end, wherein the first circumferential end and the second circumferential end define a plurality of edges on the first axially-facing side and the second axially-facing side, and wherein the first axially-facing side includes fewer edges than the second axially-facing side.
SETTER teaches:
A piston ring (Fig. 1) having a circumferentially split ring configuration having a first axially-facing side and a second axially-facing side opposite the first axially facing side (see annotated Fig. 5 below),
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the piston ring including a first circumferential end (with tongue 5) circumferentially overlapping a second circumferential end (with groove 2), wherein the first circumferential end and the second circumferential end define a plurality of edges on the first axially-facing side and the second axially-facing side, and wherein the first axially-facing side includes fewer edges (i.e. 2 edges, see Fig. 1 and Fig. 5) than the second axially-facing side (i.e. 6 edges, see Fig. 5).
Therefore, it would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to modify the piston ring seal of LEBLANC by having a first circumferential end overlapping a second circumferential end, as taught by SETTER, in order to form a tight joint so as to minimize leakage and breakage and thereby achieve the predictable result of an increase in the general efficiency and serviceability of the piston ring (SETTER column 1, lines 8-21).
Furthermore, before the effective filing date of the claimed invention there had been a recognized problem, or need in the art to solve the problem, of minimizing leakage between an area of high pressure and an area of low pressure. SETTER teaches a piston ring with two axially-facing sides that such that the piston ring may be installed to have a first side with fewer edges face the high-pressure area or the low-pressure area while the opposing side faces the low-pressure area or high-pressure area, respectively. Consequently, there were a finite number of identified and predictable potential solutions to the recognized problem, or need. Therefore, it would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to try positioning the axially-facing side with fewer edges against the low-pressure area and the axially-facing side with more edges against the high-pressure area. The results would have been predictable because the overlapping joint minimizes leakage between the areas of differing pressure (SETTER column 1, lines 8-10). Thus, one of ordinary skill in the art would have pursued the known potential solutions with a reasonable expectation of success.
(B) Regarding Claim 2:
LEBLANC as modified by ALECU and SETTER further teaches:
A first end pocket (SETTER 2, Fig. 5) formed in the first circumferential end; and a second end finger (SETTER 5, Fig. 5) formed in the second circumferential end and configured to be received in the first end pocket (SETTER Fig. 3).
(C) Regarding Claim 3:
LEBLANC as modified by ALECU and SETTER further teaches:
The first end pocket (SETTER 2, Fig. 5) is defined at least in part by a first end circumferential surface (SETTER 10), a first end axial surface (SETTER, i.e. the surface of groove 2 between corner 12 and corner 11) and a first end radial surface (SETTER i.e. the surface under the narrow portion 3 that faces the groove 2).
(D) Regarding Claim 4:
LEBLANC as modified by ALECU and SETTER further teaches:
The first end circumferential surface (SETTER 10, Fig. 5) defines a circumferential length of the first end pocket (SETTER 2), the first end axial surface (SETTER, i.e. the surface of groove 2 between corner 12 and corner 11) defines an axial width of the first end pocket, and the first end radial surface (SETTER i.e. the surface under the narrow portion 3 that faces the groove 2) defines a radial depth of the first end pocket.
(E) Regarding Claim 5:
LEBLANC as modified by ALECU and SETTER further teaches:
The second end finger (SETTER 5, Fig. 5) is defined at least in part by two or more of a second end radial surface (SETTER, i.e. along the surface forming the outermost diameter of the ring) defining a radial height of the second end finger, a second end axial surface (SETTER, i.e. the surface of tongue 5 that faces the narrow portion 3) defining an axial length of the second end finger, and a second end circumferential surface (SETTER, i.e. the surface between the corner 14 and the surface defining the outer diameter of the piston ring) defining a circumferential length of the second end finger.
(F) Regarding Claim 8:
LEBLANC as modified by ALECU and SETTER further teaches:
A gas turbine engine (LEBLANC Fig. 1), comprising:
a combustor (LEBLANC 16) configured to combust a mixture of air and fuel;
a turbine (LEBLANC 18) driven by combustion products flowed from the combustor; and
at least one piston ring (86, Fig. 3) seal arrangement of a gas turbine engine including:
a piston ring having a circumferentially split ring configuration having a first axially-facing side (i.e. facing upstream) and a second axially-facing side (i.e. facing downstream) opposite the first axially facing side, the piston ring including a first circumferential end circumferentially over lapping a second circumferential end (SETTER Fig. 5);
a mating component having a groove (LABLANC 84) into which the piston ring is installed;
wherein the first circumferential end and the second circumferential end define a plurality of edges on the first axially-facing side and the second axially-facing side (SETTER Figs. 1 and 5); and
wherein the first axially-facing side includes fewer edges (SETTER, i.e. 2 edges, Figs. 1 and 5) than the second axially-facing side (SETTER, i.e. 6 edges, Fig. 5); and
wherein the piston ring is installed in the groove such that an operating pressure acting on the piston ring is greater at the second axially-facing side (i.e. the downstream facing side, LEBLANC Fig. 3) than at the first axially-facing side (i.e the upstream facing side, LEBLANC Fig. 3) (see LEBLANC col. 1, ll. 8-16: seal to reduce leakage);
the groove has an axial groove width greater than an axial ring width of the piston ring (LEBLANC Fig. 3), such that the operating pressure moves the piston ring in the groove axially toward an axially upstream wall of the groove (ALECU para. 0036: the higher pressure P2 in the SRC is intended to bias the piston ring seal 50 against the first lateral surface 52 to produce the seal and para. 0033: the width of the piston seal ring 50 is less than the width of the seal groove (i.e., W>RW) to permit axial movement of the piston axial seal within the seal groove).
(G) Regarding Claim 9:
LEBLANC as modified by ALECU and SETTER further teaches:
A first end pocket (SETTER 2, Fig. 5) formed in the first circumferential end; and a second end finger (SETTER 5, Fig. 5) formed in the second circumferential end and configured to be received in the first end pocket (SETTER Fig. 3).
(H) Regarding Claim 10:
LEBLANC as modified by ALECU and SETTER further teaches:
The first end pocket (SETTER 2, Fig. 5) is defined at least in part by a first end circumferential surface (SETTER 10), a first end axial surface (SETTER, i.e. the surface of groove 2 between corner 12 and corner 11) and a first end radial surface (SETTER i.e. the surface under the narrow portion 3 that faces the groove 2).
(I) Regarding Claim 11:
LEBLANC as modified by ALECU and SETTER further teaches:
The first end circumferential surface (SETTER 10, Fig. 5) defines a circumferential length of the first end pocket (SETTER 2), the first end axial surface (SETTER, i.e. the surface of groove 2 between corner 12 and corner 11) defines an axial width of the first end pocket, and the first end radial surface (SETTER i.e. the surface under the narrow portion 3 that faces the groove 2) defines a radial depth of the first end pocket.
(J) Regarding Claim 12:
LEBLANC as modified by ALECU and SETTER further teaches:
The second end finger (SETTER 5, Fig. 5) is defined at least in part by two or more of a second end radial surface (SETTER, i.e. along the surface forming the outermost diameter of the ring) defining a radial height of the second end finger, a second end axial surface (SETTER, i.e. the surface of tongue 5 that faces the narrow portion 3) defining an axial length of the second end finger, and a second end circumferential surface (SETTER, i.e. the surface between the corner 14 and the surface defining the outer diameter of the piston ring) defining a circumferential length of the second end finger.
(K) Regarding Claim 15:
LEBLANC as modified by ALECU and SETTER further teaches:
The piston ring (86, LEBLANC Fig. 3) is configured to seal between a casing element (LEBLANC 68) and a vane (LEBLANC 56) of the gas turbine engine.
Claim(s) 6 and 13 is/are rejected under 35 U.S.C. 103 as being unpatentable over LEBLANC in view of ALECU and SETTER, as applied to claims 1 and 8, respectively, above, and further in view of United States Patent Application Publication No. 2022/0259975 to Heyerman (hereinafter “HEYERMAN”).
(A) Regarding Claims 6 and 13:
LEBLANC as modified by ALECU and SETTER further teaches:
A piston ring with a first circumferential end overlapping a second circumferential end (SETTER Fig. 5).
However, the difference between modified LEBLANC and the claimed invention is that modified LEBLANC does not explicitly teach a convex radius formed at at least one edge of the plurality of edges.
HEYERMAN teaches:
A piston ring with a first circumferential end overlapping a second circumferential end (Figs. 5A-5C), wherein the edges at the ends (112, 114) of the joint (110) can be rounded off (paragraph 0031).
Therefore, it would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to modify the edges of the split joint to be rounded off, as taught by HEYERMAN in order to mitigate stress concentration upon frictional engagement occurring with mating surfaces (HEYERMAN paragraph 0031) and thereby minimize fretting (HEYERMAN paragraph 0031).
Claim(s) 7 and 14 is/are rejected under 35 U.S.C. 103 as being unpatentable over LEBLANC in view of ALECU, SETTER and HEYERMAN, as applied to claims 6 and 13, respectively, above, and further in view of an engineering expedient.
(A) Regarding Claims 7 and 14:
LEBLANC as modified by ALECU and SETTER further teaches:
A convex radius is formed at two or more edges of the plurality of edges (HEYERMAN paragraph 0031).
However, the difference between modified LEBLANC and the claimed invention is that modified LEBLANC does not explicitly teach the convex radius varies at the two or more edges.
Though modified LEBLANC does not explicitly state the convex radius varies, HEYERMAN identifies that the shaping of the edges may be rounded to minimize fretting (HEYERMAN paragraph 0031). Furthermore, HEYERMAN teaches that changing the shaping of the edge can have an effect on the stress concentration upon frictional engagement of mating parts (HEYERMAN paragraph 0031). Therefore, the convex radius of the two or more edges varying is considered a result-effective variable and it would have been obvious to one having ordinary skill in the art before the effective filing date of the claimed invention to form the at least two edges with varied convex radii, since it has been held that where the general conditions of a claim are disclosed in the prior art, discovering the optimum or workable ranges involves only routine skill in the art (MPEP 2144.05 (II-A)).
Claim(s) 16-18 is/are rejected under 35 U.S.C. 103 as being unpatentable over U.S. Patent No. 3,908,361 to Gardiner (hereinafter “GARDINER”) in view of ALECU and SETTER.
(A) Regarding Claim 16:
GARDINER teaches:
A vane and case element assembly of a gas turbine engine, comprising:
a vane (Fig. 3, 29);
a case element (12) disposed radially adjacent to the vane; and
a piston ring seal disposed to seal between the vane and the case element, the piston ring seal including:
a piston ring (30) having a first axially-facing side (i.e. facing upstream) and a second axially-facing side (i.e. facing downstream) opposite the first axially facing side;
wherein the piston ring is installed into a case element groove (not numbered in Fig. 3, but formed adjacent the seal fins 14 in the downstream direction); and
wherein an operating pressure acting on the piston ring is greater at the second axially-facing side (i.e. the downstream facing side) than at the first axially-facing side (i.e. the upstream facing side) (see col. 3, ll. 6-10: prevent air from flowing from the space (34) surrounding the combustion chamber (2) forwards into the compressor);
the case element groove has an upstream axial face and a downstream axial face defining an axial groove width therebetween (see Fig. 3), the axial groove width greater than an axial ring thickness of the piston ring (i.e. the piston ring is disposed within the groove), such that in operation the first axially-facing side of the piston ring is urged axially toward the upstream axial face of the case element groove (see col. 3, ll. 31-38: pressure difference gives rise to a force on the end wall or diaphragm (37) of the casing (23) which acts to deflect the diaphragm forwardly. Since the pressure in space (34) rises as the engine speed and temperature rise this deflection acts to move the sealing element (12) to keep pace with the movement of the sealing element 11 on the compressor rotor).
However, the difference between LEBLANC and the claimed invention is that LEBLANC does not explicitly teach in operation the piston ring is moved axially in the groove toward the upstream axial face of the case element groove.
ALECU teaches:
A groove (48, Fig. 5A) has an axial groove width (W) greater than an axial ring width (RW) of a piston ring (50), such that an operating pressure (para. 0035: P2>P1) moves the piston ring in the groove axially toward an axially upstream wall of the groove (para. 0036: the higher pressure P2 in the SRC is intended to bias the piston ring seal 50 against the first lateral surface 52 to produce the seal and para. 0033: the width of the piston seal ring 50 is less than the width of the seal groove (i.e., W>RW) to permit axial movement of the piston axial seal within the seal groove).
Thus, both LEBLANC and ALECU teach a seal assembly using a piston ring positioned within a groove. Therefore, it would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to substitute the piston and groove seal arrangement of ALECU for the piston and groove seal arrangement of LEBLANC to achieve the predictable result of providing a seal between two areas of different pressure (ALECU para. 0036). See MPEP 2141(III)).
Furthermore, the Applicant has not disclosed any unexpected results to suggest that having the axial groove width so large that the piston ring moves in the groove under operating pressure provides an advantage, solves a stated problem, or is used for a particular purpose beyond the fact that the groove must be large enough to fit the piston ring and allow for temperature fluctuations in the materials, wherein the operating pressure inherently applies a force to the piston ring in the upstream direction. Furthermore, it appears that the piston and groove seal of LEBLANC would perform equally well with a difference in widths that allows for movement of the piston during an applied operating pressure because the function of the seal, i.e. to bias against the upstream face of the groove under an operating pressure, remains the same. Therefore, it would have been an obvious matter of design choice to modify the groove and/or piston widths to obtain the claimed invention and thereby achieve the predictable result of sealing between two different areas of pressure (ALECU para. 0036).
However, the difference between GARDINER and the claimed invention is that GARDINER does not explicitly teach the piston ring having a circumferentially split ring configuration having a first circumferential end circumferentially over lapping a second circumferential end, wherein the first circumferential end and the second circumferential end define a plurality of edges on the first axially-facing side and the second axially-facing side, and wherein the first axially-facing side includes fewer edges than the second axially-facing side.
SETTER teaches:
A piston ring (Fig. 1) having a circumferentially split ring configuration having a first axially-facing side and a second axially-facing side opposite the first axially facing side (see annotated Fig. 5 further above), the piston ring including a first circumferential end (with tongue 5) circumferentially overlapping a second circumferential end (with groove 2), wherein the first circumferential end and the second circumferential end define a plurality of edges on the first axially-facing side and the second axially-facing side, and wherein the first axially-facing side includes fewer edges (i.e. 2 edges, see Fig. 1 and Fig. 5) than the second axially-facing side (i.e. 6 edges, see Fig. 5).
Therefore, it would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to modify the piston ring seal of GARDINER by having a first circumferential end overlapping a second circumferential end, as taught by SETTER, in order to form a tight joint so as to minimize leakage and breakage and thereby achieve the predictable result of an increase in the general efficiency and serviceability of the piston ring (SETTER column 1, lines 8-21).
Furthermore, before the effective filing date of the claimed invention there had been a recognized problem, or need in the art to solve the problem, of minimizing leakage between an area of high pressure and an area of low pressure. SETTER teaches a piston ring with two axially-facing sides that such that the piston ring may be installed to have a first side with fewer edges face the high-pressure area or the low-pressure area while the opposing side faces the low-pressure area or high-pressure area, respectively. Consequently, there were a finite number of identified and predictable potential solutions to the recognized problem, or need. Therefore, it would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to try positioning the axially-facing side with fewer edges against the low-pressure area and the axially-facing side with more edges against the high-pressure area. The results would have been predictable because the overlapping joint minimizes leakage between the areas of differing pressure (SETTER column 1, lines 8-10). Thus, one of ordinary skill in the art would have pursued the known potential solutions with a reasonable expectation of success.
(B) Regarding Claim 17:
GARDINER as modified by ALECU and SETTER further teaches:
A first end pocket (SETTER 2, Fig. 5) formed in the first circumferential end; and a second end finger (SETTER 5, Fig. 5) formed in the second circumferential end and configured to be received in the first end pocket (SETTER Fig. 3).
(C) Regarding Claim 18:
GARDINER as modified by ALECU and SETTER further teaches:
The first end pocket (SETTER 2, Fig. 5) is defined at least in part by a first end circumferential surface (SETTER 10), a first end axial surface (SETTER, i.e. the surface of groove 2 between corner 12 and corner 11) and a first end radial surface (SETTER i.e. the surface under the narrow portion 3 that faces the groove 2).
Claim(s) 19 is/are rejected under 35 U.S.C. 103 as being unpatentable over GARDINER in view of ALECU and SETTER, as applied to claim 16 above, and further in view of HEYERMAN.
(A) Regarding Claim 19:
GARDINER as modified by ALECU and SETTER further teaches:
A piston ring with a first circumferential end overlapping a second circumferential end (SETTER Fig. 5).
However, the difference between modified GARDINER and the claimed invention is that modified GARDINER does not explicitly teach a convex radius formed at at least one edge of the plurality of edges.
HEYERMAN teaches:
A piston ring with a first circumferential end overlapping a second circumferential end (Figs. 5A-5C), wherein the edges at the ends (112, 114) of the joint (110) can be rounded off (paragraph 0031).
Therefore, it would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to modify the edges of the split joint to be rounded off, as taught by HEYERMAN in order to mitigate stress concentration upon frictional engagement occurring with mating surfaces (HEYERMAN paragraph 0031) and thereby minimize fretting (HEYERMAN paragraph 0031).
Claim(s) 20 is/are rejected under 35 U.S.C. 103 as being unpatentable over GARDINER in view of ALECU, SETTER and HEYERMAN, as applied to claim 19 above, and further in view of an engineering expedient.
(A) Regarding Claim 20:
GARDINER as modified by ALECU and SETTER further teaches:
A convex radius is formed at two or more edges of the plurality of edges (HEYERMAN paragraph 0031).
However, the difference between modified GARDINER and the claimed invention is that modified GARDINER does not explicitly teach the convex radius varies at the two or more edges.
Though modified GARDINER does not explicitly state the convex radius varies, HEYERMAN identifies that the shaping of the edges may be rounded to minimize fretting (HEYERMAN paragraph 0031). Furthermore, HEYERMAN teaches that changing the shaping of the edge can have an effect on the stress concentration upon frictional engagement of mating parts (HEYERMAN paragraph 0031). Therefore, the convex radius of the two or more edges varying is considered a result-effective variable and it would have been obvious to one having ordinary skill in the art before the effective filing date of the claimed invention to form the at least two edges with varied convex radii, since it has been held that where the general conditions of a claim are disclosed in the prior art, discovering the optimum or workable ranges involves only routine skill in the art (MPEP 2144.05 (II-A)).
Conclusion
Any inquiry concerning this communication or earlier communications from the examiner should be directed to KAYLA M MCCAFFREY whose telephone number is (571)272-3438. The examiner can normally be reached Monday - Friday (excluding Wednesday) 10AM - 2 PM EST.
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KAYLA M. MCCAFFREY
Primary Examiner
Art Unit 3745
/Kayla McCaffrey/Primary Examiner, Art Unit 3745
Prosecution Insights