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and the fee set forth in 37 CFR 1.17(e) has been timely paid, the finality of the previous Office action has been withdrawn pursuant to 37 CFR 1.114.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 08/04/2025 has been entered.
Response to Arguments
Applicant’s arguments with respect to claims 1, 9, 15, and 21 have been considered but are moot because the new ground of rejection does not rely on any reference applied in the prior rejection of record for any teaching or matter specifically challenged in the argument.
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.
Claims 1, 9, and 15 are rejected under 35 U.S.C. 103 as being unpatentable over Bacic (US Patent 8,894,358 B2) in view of Terwilliger et al. (US Patent 11,111,809 B2).
Regarding claim 1, Bacic discloses a gas turbine engine (Fig. 1) comprising:
a shroud segment (48,50);
a rotor blade (44) rotatable relative to the shroud segment, a clearance (52) being defined directly (Col. 4:6-13) between the shroud segment and the rotor blade (Fig. 3).
a clearance adjustment system (Fig. 3, Fig. 4) having a piezoelectric actuator (58, Col. 3:31-33) coupled to the shroud segment and configured to adjust the clearance according to a clearance control scheme (Fig. 2); and
an engine controller (62) in operable communication with the clearance adjustment system (Fig. 3), the engine controller having one or more processors (Col. 3:28-45 indicates that the controller is either part of the electronic controller of the gas turbine engine or a separate controller) configured to implement the clearance control scheme, the one or more processors are configured to:
receiver sensor data from one or more sensors (64);
receive additional data associated with an engine event (Fig. 2, see Taxi/Take Off/Climb/Cruise), wherein the additional data indicative that the gas turbine engine is engaged in an engine acceleration event (Col. 2:58-3:11), wherein the additional data includes at least one of a change in throttle or throttle angle (Col. 2:58-3:11, implied as each of these stages of flight require a change in throttle or throttle angle);
generate a current clearance (34) based on at least one of the sensor data and the additional data associated with the engine event;
generate a target clearance (36) based on at least one of the sensor data and the additional data associated with the engine event, wherein, to generate the target clearance, the one or more processors is further configured to:
determine a predicted mechanical deflection of the rotor blade that occurs as a result of the engine acceleration event (36, 38; Col. 2:58-3:11 “a target tip clearance 37 that is calculated as the sum of a clearance required to take account of measurement uncertainties or errors 38 and a clearance required to take account of asymmetries in the radial extend of the blade set 40”);
determine an acceleration clearance required to prevent a rub event based on the determined predicted mechanical deflection of the rotor blade (“a target tip clearance 37 that is calculated as the sum of a clearance required to take account of measurement uncertainties or errors 38 and a clearance required to take account of asymmetries in the radial extend of the blade set 40”);
compare the target clearance to the current clearance (Col. 4:6-13); and
cause the clearance adjustment system to adjust the clearance to the target clearance based on the comparison by actuating the piezoelectric actuator (Col. 4:6-13).
However, Bacic does not explicitly disclose, “determine a rate of change in the throttle position or throttle angle;”
Terwilliger et al. teaches, in the field of clearance control that the controller(s) “In various embodiments, controller 280 may control the temperature of heating element 210 based upon various operating conditions, including altitude, throttle position, rotor speed, and bleed pressure, among others. (Col. 6:55-59)” and “Rather, blade tip clearance G is configured to be optimal at cruise conditions (“default closed”) and heating element 210 is used to maintain clearance gap G in response to events that would otherwise cause blade tip strike, e.g. in response to a throttle acceleration. (Col. 8:24-28)”.
It would have been obvious to one of ordinary skill in the art before the effective filing date to modify the control system of Bacic to recognize that “throttle acceleration” e.g., “throttle rate of range” is a relevant factor in clearance control and therefore configure their controller to maintain the clearance gap in response to throttle acceleration to avoid blade tip strike (e.g., determine the predicted mechanical deflection and determine the clearance required to avoid said blade tip strike) (See Col. 6:55-59 and Col. 8:24-28) as taught by Terwilliger et al. and both references are in the same field of endeavor, and one of ordinary skill would appreciate both, “In various embodiments, controller 280 may control the temperature of heating element 210 based upon various operating conditions, including altitude, throttle position, rotor speed, and bleed pressure, among others. (Col. 6:55-59)” and “Rather, blade tip clearance G is configured to be optimal at cruise conditions (“default closed”) and heating element 210 is used to maintain clearance gap G in response to events that would otherwise cause blade tip strike, e.g. in response to a throttle acceleration. (Col. 8:24-28)”.
Regarding claim 9, the combination of Bacic and Terwilliger et al. teaches all of claim 1 as above,
wherein the acceleration data indicative that the gas turbine engine is engaged in the engine acceleration event includes data indicative of a change in power demand (Bacic; Fig. 2, Take-off, Climb, Cruise, etc.).
Regarding claim 15, Bacic discloses a gas turbine engine (Fig. 1) comprising:
a shroud segment (48,50);
a rotor blade (44) rotatable relative to the shroud segment, a clearance (52) being directly (Col. 4:6-13) defined between the shroud segment and the rotor blade (Fig. 3),
a clearance adjustment system (Fig. 3, Fig. 4) configured to adjust the clearance according to a clearance control scheme (Fig. 2); and
an engine controller (62) in operable communication with the clearance adjustment system (Fig. 3), the engine controller having one or more processors (Col. 3:28-45 indicates that the controller is either part of the electronic controller of the gas turbine engine or a separate controller) configured to implement the clearance control scheme, the one or more processors are configured to:
receive sensor data from one or more sensors (64);
receive additional data associated with an engine event (Fig. 2, see Taxi/Take Off/Climb/Cruise), wherein the additional data indicative that the gas turbine engine is engaged in an engine acceleration event (Col. 2:58-3:11), wherein the additional data includes at least one of a change in throttle or throttle angle (Col. 2:58-3:11, implied as each of these stages of flight require a change in throttle or throttle angle);
generate a current clearance (34) based on at least one of the sensor data and the additional data associated with the engine event;
generate a target clearance (36) based on at least one of the sensor data and the additional data associated with the engine event, wherein, to generate the target clearance, the one or more processors is further configured to:
determine a predicted mechanical deflection of the rotor blade that occurs as a result of the engine acceleration event (36, 38; Col. 2:58-3:11 “a target tip clearance 37 that is calculated as the sum of a clearance required to take account of measurement uncertainties or errors 38 and a clearance required to take account of asymmetries in the radial extend of the blade set 40”);
determine an acceleration clearance required to prevent a rub event based on the determined predicted mechanical deflection of the rotor blade (“a target tip clearance 37 that is calculated as the sum of a clearance required to take account of measurement uncertainties or errors 38 and a clearance required to take account of asymmetries in the radial extend of the blade set 40”);
compare the target clearance to the current clearance (Col. 4:6-13); and
cause the clearance adjustment system to adjust the clearance to the target clearance based on the comparison (Col. 4:6-13).
However, Bacic does not explicitly disclose, “determine a rate of change in the throttle position or throttle angle;”
Terwilliger et al. teaches, in the field of clearance control that the controller(s) “In various embodiments, controller 280 may control the temperature of heating element 210 based upon various operating conditions, including altitude, throttle position, rotor speed, and bleed pressure, among others. (Col. 6:55-59)” and “Rather, blade tip clearance G is configured to be optimal at cruise conditions (“default closed”) and heating element 210 is used to maintain clearance gap G in response to events that would otherwise cause blade tip strike, e.g. in response to a throttle acceleration. (Col. 8:24-28)”.
It would have been obvious to one of ordinary skill in the art before the effective filing date to modify the control system of Bacic to recognize that “throttle acceleration” e.g., “throttle rate of range” is a relevant factor in clearance control and therefore configure their controller to maintain the clearance gap in response to throttle acceleration to avoid blade tip strike (e.g., determine the predicted mechanical deflection and determine the clearance required to avoid said blade tip strike) (See Col. 6:55-59 and Col. 8:24-28) as taught by Terwilliger et al. and both references are in the same field of endeavor, and one of ordinary skill would appreciate both, “In various embodiments, controller 280 may control the temperature of heating element 210 based upon various operating conditions, including altitude, throttle position, rotor speed, and bleed pressure, among others. (Col. 6:55-59)” and “Rather, blade tip clearance G is configured to be optimal at cruise conditions (“default closed”) and heating element 210 is used to maintain clearance gap G in response to events that would otherwise cause blade tip strike, e.g. in response to a throttle acceleration. (Col. 8:24-28)”.
Claim 21 is rejected under 35 U.S.C. 103 as being unpatentable over Bacic and Terwilliger et al. as applied to claim 1 above, and further in view of Kim (US PGPUB 2022/0178266 A1).
Regarding claim 21, the combination Bacic and Terwilliger et al. teach all of claim 1 as above, wherein the piezoelectric actuator includes a includes a stack of piezoelectric material disposed within a housing (56, Fig. 4 shows the piezoelectric material 58 housed between additional layers of metal), and wherein the piezoelectric actuator is attached to the shroud segment via one or more hangers (Fig. 3, 50 is attached via a hanger 48).
However, Bacic does not disclose “a multilayer stack of piezoelectric material”
Kim teaches, in the field of active clearance control using piezoelectric actuators, a multilayer stack of piezoelectric material (450, [0029]).
It would have been obvious to one of ordinary skill in the art before the effective filing date to modify the piezoelectric actuator of Bacic by adding additional piezoelectric layers as taught by Kim, and one of ordinary skill would appreciate that, “The range of displacement is increased by adding layers of piezoelectric material or SMA, called multilayer stacks, where more layers in a stack provides more radial movement range and gives the ACC system more muscle capability. [0029]).
Conclusion
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/RYAN C CLARK/ Examiner, Art Unit 3745