SAFRAN AIRCRAFT ENGINES

Patent Trials and Appeals Board

Aug 26, 2021

2021001820 (P.T.A.B. Aug. 26, 2021)

UNITED STATES PATENT AND TRADEMARK OFFICE
UNITED STATES DEPARTMENT OF COMMERCE
United States Patent and Trademark Office
Address: COMMISSIONER FOR PATENTS
P.O. Box 1450
Alexandria, Virginia 22313-1450
www.uspto.gov
APPLICATION NO. FILING DATE FIRST NAMED INVENTOR ATTORNEY DOCKET NO. CONFIRMATION NO.
15/302,902 10/07/2016 Sebastien MARIN 477962US41PCT 1024
22850 7590 08/26/2021
OBLON, MCCLELLAND, MAIER & NEUSTADT, L.L.P.
1940 DUKE STREET
ALEXANDRIA, VA 22314
EXAMINER
WOLCOTT, BRIAN P
ART UNIT PAPER NUMBER
3745
NOTIFICATION DATE DELIVERY MODE
08/26/2021 ELECTRONIC
Please find below and/or attached an Office communication concerning this application or proceeding.
The time period for reply, if any, is set in the attached communication.
Notice of the Office communication was sent electronically on above-indicated "Notification Date" to the
following e-mail address(es):
OBLONPAT@OBLON.COM
iahmadi@oblon.com
patentdocket@oblon.com
PTOL-90A (Rev. 04/07)
UNITED STATES PATENT AND TRADEMARK OFFICE
____________________

BEFORE THE PATENT TRIAL AND APPEAL BOARD
____________________

Ex parte SEBASTIEN MARIN
____________

Appeal 2021-001820
Application 15/302,902
Technology Center 3700
____________

Before CHARLES N. GREENHUT, ANNETTE R. REIMERS, and
LISA M. GUIJT, Administrative Patent Judges.

GUIJT, Administrative Patent Judge.

DECISION ON APPEAL

STATEMENT OF THE CASE
Appellant1 seeks our review under 35 U.S.C. § 134(a) of the rejection
of claims 10 and 12–15 under 35 U.S.C. § 103 as unpatentable over
Szpunar,2 Jevons,3 and Bassot.4,5 We have jurisdiction under 35 U.S.C.
§ 6(b).

1 We use the word “Appellant” to refer to “applicant” as defined in 37
C.F.R. § 1.42. Appellant identifies Safron Aircraft Engines as the real party
in interest. Appeal Br. 3.
2 US 5,259,728; issued Nov. 9, 1993.
3 US 9,745,995 B2; issued Aug. 29, 2017.
4 US 6,910,866 B2; issued June 28, 2005.
5 The Examiner’s rejection of claims 10 and 12–15 under 35 U.S.C.
§ 112(b) has been withdrawn. Advisory Act. 1; Ans. 3.
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We REVERSE.

THE INVENTION
Appellant’s invention relates to “a turbine engine rotor lock.” Spec.
1:4–6. Claim 1, reproduced below as the sole independent claim, is
illustrative of the subject matter on appeal.
10. A turbine engine rotor comprising:
a disk;
blades attached to the disk;
a lock for the turbine engine rotor, the lock retaining at
least one of the blades axially relative to the disk of the turbine
engine rotor, the lock including:
a composite body comprising a woven fiber structure
embedded in a matrix, and
a damper pad made of elastomer and fastened to the
composite body,
wherein the woven fiber structure comprises warp yarns
and weft yarns oriented such that when the lock is in position on
the turbine engine rotor, the warp yarns are oriented in a
tangential direction of the turbine engine rotor and the weft yarns
are oriented in a radial direction of the turbine engine rotor, or
vise versa,
wherein each blade is fastened in a slot of the disk by a
blade root,
wherein the lock is fastened to an axial end of the slot for
said at least one of the blades, and
wherein the damper pad is situated between the blade root
and the composite body.

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OPINION
Regarding independent claim 10, the Examiner finds that Szpunar
discloses a lock (i.e., a blade retainer 38) that retains a blade axially relative
to a disk, wherein each blade is fastened in a disk’s slot by a blade root (i.e.,
via dovetail 32), and the lock is fastened to an axial end of the slot, as
claimed. Final Act. 5 (citing Szpunar 1:5–10, 2:10–20, 2:57–60, 3:44–48,
Figs. 1–3, 6–8). The Examiner also finds that each of Szpunar’s lock (or
blade retainer 38) includes a damper pad (i.e., spacer 48) fastened to a body
(i.e., retainer plate 42) of the lock and situated between the blade root and
the lock’s body. Id. (citing Szpunar 6:38–43, Fig. 3).6
The Examiner determines that Szpunar, as modified by Jevons, fails to
disclose a damper pad made of elastomer, as required by claim 1, and relies

6 The Examiner relies on Jevons for disclosing a similar rotor lock (i.e.,
retainer plate 44) comprised of a “polymer matrix fiber-reinforced composite
material with at least a portion of the reinforcement being 3D woven fiber.”
Final Act. 5–6 (citing Jevons 5:40–44, 6:39–44). The Examiner reasons that
it would have been obvious to an ordinarily skilled artisan to have replaced
the material of Szpunar’s lock body with 3D woven composite material, as
taught by Jevons, to provide, for example, weight reduction and increased
strength. Id. at 6–7 (citing Jevons 1:65–2:6); see Ans. 6; id. (reasoning that
“Jevons teaches that the use of a known material, 3D woven composite, is
suitable for rotor lock bodies,” and thus, modifying Szpunar’s lock body, in
view of Jevons, “is merely the selection of an art known material suitable for
use in the construction of a rotor lock body”); id. at 7 (reasoning that
“[d]etermining the specific arrangement of the fibers for a particular
application is well within the ordinary skill level of one in the art”); see also
Jevons 1:65–2:6 (disclosing that “[a] 3D-woven composite material retainer
plate can provide significant weight-reduction compared with conventional,
typically metallic, shear plates” and that “[a]lternatively, for the same
weight, the strength of the plate can be improved, allowing the plate to
withstand greater axial loads”).

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on Bassot for disclosing a similar lock adapted to retain a fan blade
comprising a damper pad of elastomer (i.e., peg 17). Final Act. 7 (citing
Bassot 1:5–8, 3:22–28). The Examiner reasons that it would have been
obvious to an ordinarily skilled artisan to have modified Szpunar, as
modified by Jevons, “to construct the damper pad of elastomer to ensure
sufficient force is exerted on the blade roots such that they are positively
pressed against the rotor lock body as this eliminates any axial clearance
regardless of manufacturing tolerances” (citing Bassot 2:12–16) and also so
that “the elastomer can be custom tailored to provide the desired amount of
resiliency to suite the application (citing Bassot 2:17–18). Id. The
Examiner also reasons that “the elements of Szpunar and Bassot, in
combination are being employed in accordance with their recognized
functions and would have predictably retained their respective functions
[such that] there is a reasonable expectation of success.” Ans. 8. The
Examiner further determines that “Appellant has provided no evidence nor
any fact based rationale to show why or how the spacer would not function
as intended if made from elastomer versus honeycomb” and reasons that “[a]
person having ordinary skill in the art having read [Szpunar] would readily
understand that the elastomer would remain in contact for normal operation
but may not (by deforming) during exceptional foreign body ingestion
evens, such as large bird strikes.” Id. The Examiner concludes that “as
Bassot teaches that the use of a known material, elastomer, is suitable for use
in rotor lock body spacers, it is merely the selection of an art known material
suitable for use in the construction of a rotor lock body spacer.” Id.
Appellant argues that
one having ordinary skill in the art would not have had a
reasonable expectation of success, based on the general mention
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of elastomer in Bassot, that changing the honeycomb structure of
Szpunar’s forward spacer 48 to be made of elastomer would have
still been able to “remain rigid and intact during normal operation
and for small bird strikes” and also “buckl[e] upon reaching a
predetermined limit Fmax of the axial impact force Fa transmitted
from the dovetail 26 to the blade retainer 38 through the forward
spacer 48 during a large bird strike” as required by Szupnar.
Appeal Br. 11–12 (citing Szpunar 5:1–6). Appellant submits that the
Examiner’s proposed modification of Szupnar in view of Bassot changes the
principle of operation of Szpunar, such that Szpunar would fail to perform
its intended purpose. Id. at 12.
Szpunar discloses that “[a] spacer is disposed in the slot between the
blade retainer and the dovetail and is selectively compressible for allowing
the dovetail to slide in the slot toward the blade retainer for generating
friction forces to dissipate energy upon impact of a predeterminedly sized
foreign object.” Szpunar 2:10–20. In particular, Szpunar discloses, as
argued by Appellant, that
forward spacer 48 is preferably sized and configured for
remaining rigid and intact during normal operation and for small
bird strikes, and buckling upon reaching a predetermined limit
Fmax of the axial impact force Fa transmitted from the dovetail 26
to the blade retainer 38 through the forward spacer 48 during a
large bird strike.
Id. 4:68–5:6. Szpunar explains that “energy from the bird strike is dissipated
by the buckling of the forward spacer 48 itself, as well as by the substantial
friction forces between the dovetail 26 and the dovetail slot 32 as the
dovetail 26 slides therein.” Id. at 6:18–22. Szpunar discloses that, in an
exemplary embodiment, “forward spacer 48 [may be] in the form of a
conventional hexagonal honeycomb having a plurality of honeycomb cells
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50 which is substantially rigid for reacting axial loads during normal
operation” (id.. at 6:44–49), however,
forward spacer 48 may take any suitable alternate form having
the ability to transmit axial force therethrough from the dovetail
26 to the retainer plate 42 without significant movement of the
dovetail 26 below the predetermined axial force limit Fmax, but
upon reacting that limit, the forward spacer 48 should be suitably
compressible for allowing sliding movement of the dovetail 26
within the slot 32 for dissipating energy by friction.
Id. at 7:23–31. Szpunar discloses specific examples of forward spacer 48
including “a bladder containing a viscous fluid” (id. at 7:34–35) and “a
plurality of axially aligned pins in a suitable matrix,” wherein “the pins . . .
buckle” (id. at 8:23–27). Szpunar discloses that forward spacer 48 “in
combination with [the] blade retainer[] suitably rigidly retain the dovetail[]
26 without axial movement under normal operation conditions, but allow
axial movement of the dovetail 26 during the bird strike occurrence, for
example, for dissipating the energy therefrom.”7 Id. at 8:28–35.
Figure 3 of Szpunar is reproduced below.

7 Szpunar also discloses that an aft spacer 58 may also be used “at the
opposite or aft end of the dovetail 26 against the radial flange 16a,” wherein
“aft spacer 58 is preferably substantially identical to the forward spacer 48 in
structure and in operation.” Szpunar 8:13–18.
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Figure 3 of Szpunar is “a perspective view, in part blowup, of [a] bladed
disk assembly . . . showing three adjacent dovetail slots for receiving
respective fan blades retained therein” (Szpunar 2:34–36), including retainer
plate 42 and forward spacer 48.
Bassot discloses that “[f]or assembly reasons, axial clearance is
included in the connection between a blade and the disks,” and “[t]he
random axial position of a fan blade within this clearance unbalances the
rotor and generates vibration in operation.” Bassot 1:29–32. Bassot notes
that, as disclosed in Szupnar supra, the prior art “provides for interposing
honeycomb elements between the retaining flange plates and the ends of the
blade roots, the honeycomb elements serving to absorb a portion of the
energy in the event of birds being ingested,” however, “[t]he honeycomb
elements must retain their integrity during assembly of the flange plates, and
as a result there inevitably exists some axial clearance after assembly,
thereby making random axial displacement possible while the fan is in
operation.” Id. at 51–62 (citing Szpunar ’720 (US 5,282,720; issued Feb. 1,
1994)). Thus, according to Bassot’s invention, “the upstream flange plate is
fitted on its downstream face with resilient means for exerting sufficient
force on the upstream faces of the blade roots, after assembly, to prevent any
axial displacement of the blades during normal operation of the engine.” Id.
at 2:3–8. In other words, “once the rotor has been assembled, these resilient
means exert sufficient fore on the blade roots to ensure that they are held
positively pressed against the upstream flange plate, thereby eliminating any
axial assembly clearance regarding of the manufacturing tolerances of the
blades,” wherein the resilient means are preferably “elastomer pegs held in
respective orifices formed in the flange plate.” Id. at 2:12–20. Bassot
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further discloses, with reference to Figure 2, that “upstream flange plate 12
has an orifice 15 in front of each blade root 4, which orifice holds the shank
16 of an elastomer peg 17,” such that
peg 17 exerts elastic forces on the lug 8 [of spacer 6] in an axial
direction. Since lug 8 is pressed against the adjacent blade root
4, the root is continuously urged towards the downstream flange
plate against which it remains in abutment. This simple
disposition serves to control the axial clearance of the blades 3
and to prevent the blades 3 from moving axially in random
manner.
Id. at 3:12–14, 21–27.
Figures 2, 3, 4A, and 4B of Bassot are reproduced below.

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Figures 2, 3, and 4A, and 4B of Bassot are detailed views of “the disposition
of the upstream flange plate and a blade, showing the assembly clearance
[J]” (Bassot 2:33–38), which is addressed by using elastomer peg 17 (see,
e.g., Bassot 3:12–16).
Thus, Szpunar’s forward spacer 48 (or damper pad) is positioned
between retainer plate 2 and dovetail 26 to selectively compress when
maximum force is applied, as compared to the function of Bassot’s
elastomer peg, which urges a blade root toward the downstream face of a
rotor disk to eliminate axial clearance after assembly—and which may
specifically address the axial clearance remaining after assembly of flange
plates and honeycomb elements, similar to Szupnar’s spacer 48.
We are persuaded by Appellant’s argument that the Examiner’s
reasoning “to construct [Szpunar’s forward spacer 48] of elastomer to ensure
sufficient force is exerted on the blade roots such that they are positively
pressed against the rotor lock body [to] eliminate[] axial clearance regardless
of manufacturing tolerances” lacks rational underpinning. Final Act. 7.
The Examiner does not make of record sufficient evidence or technical
reasoning to demonstrate why, without the benefit of hindsight, the skilled
artisan would regard teachings relating to the material of Bassot’s peg 17
used to take up axial clearance as relevant to Szpunar’s forward spacer 48,
which serves a very different purpose—to be selectively compressible when
a maximum force is applied (i.e., via a bird strike). Additionally, we
determine that the Examiner’s conclusion that a person of ordinary skill in
the art would readily understand that an elastomer, as taught in Bassot,
would remain in contact with the blade root, in Szpunar, during normal
operation but would deform during a bird strike, or that an elastomer is
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suitable for use as Szpunar’s forward spacer 48, is speculative and
insufficiently supported by evidence.
Accordingly, we do not sustain the Examiner’s rejection of
independent claim 10, and claims 12–15 depending therefrom.
CONCLUSION
The Examiner’s decision rejecting claims 10 and 12–15 is reversed.

DECISION SUMMARY
In summary:
Claim(s)
Rejected
35
U.S.C.
§
Reference(s)/Basis Affirmed Reversed
10, 12–15 103 Szpunar, Jevons, Bassot 10,12–15

REVERSED