DETAILED ACTION
This office action is responsive to the amendment filed on 02/27/26. As directed by the amendment: claims 1 has been amended; claims 2, 4, 6, 8, 10, 12, 14, and 16 have been cancelled; and no claims have been added. Thus, claims 1, 3, 5, 7, 9, 11, 13, and 15 are presently pending in this application.
The present application, filed on or after March 16, 2013, is being examined under the first inventor to file provisions of the AIA .
Claim Rejections - 35 USC § 103
In the event the determination of the status of the application as subject to AIA 35 U.S.C. 102 and 103 (or as subject to pre-AIA 35 U.S.C. 102 and 103) is incorrect, any correction of the statutory basis (i.e., changing from AIA to pre-AIA ) for the rejection will not be considered a new ground of rejection if the prior art relied upon, and the rationale supporting the rejection, would be the same under either status.
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, 3, 5, 7, 9, 11, 13, and 15 are rejected under 35 U.S.C. 103 as being unpatentable over Chikaumi (WO 2016174842) in view of JFE (WO 2018123350)
With regard to claim 1, Chikaumi teaches a resistance spot welding method (“in a resistance spot welding method”, cl. 1) for joining two or more steel sheets (11/12/13, FIG. 3a) including at least one steel sheet having a tensile strength of 980 MPa or higher (Sheet Combination A – Table 1; Sheet 12 is a 980 Mpa-grade cold rolled steel sheet) , the method involving placing the steel sheets on top of each other (FIG. 3a in which at least steel sheets 11/12/13 are stacked) to form a set of steel sheets to be welded (FIG. 3a illustrates welding via electrodes 14), clamping the set of steel sheets (11/12/13) with a pair of electrodes (upper/lower electrodes 14, FIG. 3a), and passing a current through the steel sheets (11/12/13) while applying pressure thereto to join the steel sheets together, the resistance spot welding method comprising: an initial welding step of welding by passing a current I1 (kA) satisfying relation (2) while applying a welding force F1 (kN) satisfying relation (1), 0.2×√t 1 <F 1≤4×√t 1 (1) 2×√F 1 <I 1≤10×√F 1 (2) where t1 is a total sheet thickness (mm) of the steel sheets to be welded (Table 2 illustrates a Joint #1 three steel plates (see plate group A in Table 1) having plate thicknesses of .7 mm, 2.0 mm, and 2.0 mm (i.e., a total plate thickness of 4.7 mm) which are welded in the first step at a pressing force of 3.5 kN and a welding current of 8.0 kA; or alternatively see plate group D in table 1 with an emphasis upon Joint #6 in which two steel plates having replate thicknesses of 2.0 mm and 2.0 mm (i.e. a total plate thickness of 4.7 mm) are welded in the first step at a pressing force of 3.5 kN and a welding current of 8.0kA; therefore, relations (1) and (2) of claim 1 of the instant patent application are satisfied with either of the aforementioned Joint #1 and/or Joint #6); and a main welding step of forming a nugget having a predetermined nugget diameter after the initial welding step (“In the example of the invention, a sufficient minimum thickness of the welded portion was obtained, and a nugget having a diameter of 4 √ {square root over (t)} or more was obtained between the thin plate and the thick plate and between the thick plate and the thick plate “, pg. 8, ln. 1-2) wherein spatter is produced in the initial welding step (scattering produced initially is suppressed: “the inventors further investigated in order to prevent further scattering when scattering occurred once during welding. As a result, the energization pattern is split into two or more steps to perform adaptive control welding, and a scattering occurrence detection means is provided. When occurrence of scattering is detected during welding by this detection means, By reducing the target calorific value and adjusting the energization amount, specifically the welding current and the interelectrode voltage, based on this reduced target calorific value, occurrence of further scattering can be prevented and a nugget of an appropriate diameter Can be obtained.”, pg. 3, ln. 54-58).
Although Chikaumi does not explicity teach the claimed formulaic ranges, it is submitted that in the case where the claimed ranges "overlap or lie inside ranges disclosed by the prior art" a prima facie case of obviousness exists. In re Wertheim, 541 F.2d 257, 191 USPQ 90 (CCPA 1976); In re Woodruff, 919 F.2d 1575, 16 USPQ2d 1934 (Fed. Cir. 1990) (see MPEP 2144.05 Obviousness of Similar and Overlapping Ranges, Amounts, and Proportions).
Therefore, it would have been obvious before the effective date of the claimed invention to one of ordinary skill in the art to modify the device in the Chikaumi reference to arrive at the claimed formulaic ranges, as suggested and taught by the prior art citation, for the purpose of providing an optimized spot welded joint.
Chikaumi does not explicitly teach spatter for discharging a hydrogen source present at an interface of the steel sheets is produced within 40 ms of the start of welding and a welding time in the initial welding step is within 80 ms; however, JFE which is from the same field of endeavor as Chikaumi directed toward a resistance spot welding method teaches the aforementioned limitation: Table 1-2 teaches sample 40 which teaches an initial energization time (ta) of 80-120 ms and a pressurization delay (tb) of 40 ms.
Therefore, it would have been obvious before the effective date of the claimed invention to one of ordinary skill in the art to modify the device in the Chikaumi reference, such that spatter for discharging a hydrogen source present at an interface of the steel sheets is produced within 40 ms of the start of welding and a welding time in the initial welding step is within 80 ms, as suggested and taught by JFE, for the purpose of minimizing inclusion of hydrogen within a weld to avoid fracture. Notwithstanding the foregoing, it is submitted that the aforementioned limitations would have been obvious before the effective date of the claimed invention to one of ordinary skill in the art as a matter of routine experimentation to determine an initial welding time and a time for determining when a spatter is present based upon observable test conditions presented in view of a given energization value utilized.
With regard to the recitation of claim 1 of the instant patent application regarding an initial welding
step and a main welding step with spatter being produced within 40 ms in the initial welding step, it must be stressed that the written description of the instant patent application explicitly states: “In accordance with aspects of the present invention, it is preferable to produce spatter within 200 ms of the start of welding in the initial welding step. It is more preferable to produce spatter within 100 ms of the start of welding in the initial welding step. The minimum time from the start of welding to the occurrence of spatter is not limited to a particular length, but it is preferable that it be 20 ms or more.” Accordingly, in view of the aforementioned explicit teaching from the written description of the instant patent application, it is submitted that the claimed limitation of 40 ms of spatter discharge occurring in the initial welding step is not critical to the instant invention of independent claim 1 of the instant patent application in view of the explicit teachings of the written description as the written description does not indicate any unexpected results regarding the aforementioned limitation as the invention is operable with the production of spatter even within 200 ms of the start of welding. Notwithstanding the foregoing, as detailed in the obviousness rejection, the secondary citation (JFE) teaches at Table 1-2 a sample 40 which teaches an initial energization time (ta) of 80-120 ms and a pressurization delay (tb) of 40 ms. Additionally, as the primary prior art citation (Chikaumi) teaches the claimed values of relations (1) and (2) of claim 1 of the instant patent application as detailed above in combination with the aforementioned explicit non-criticality, it is submitted that such a limitation would have been obvious before the effective date of the claimed invention to one of ordinary skill in the art as a matter of routine experimentation to achieve a desired weld-strength of a formed nugget. However, assuming it was determined that the secondary prior art citation did not teach the limitations as detailed above, it would have been obvious before the effective date of the claimed invention to one of ordinary skill in the art to modify the timing of the initial welding step as a matter of routine experimentation as the primary citation (Chikaumi) teaches at FIG. 1A a voltage application between electrodes (kv) until an expulsion occurs (plotted against welding time in cycles), and upon detection of expulsion, the voltage is reduced as illustrated in FIG. 1A (as reproduced hereafter). Furthermore, this figure of Chikaumi details a primary advantage/result of the invention of claim 1 of the instant patent application related to controlling the level of spatter by controlling the amount of voltage drop at the occurrence of spatter (see written description of the instant patent application at para. [0047]: “To stably form a large diameter nugget in the main welding step described below, it is preferable that the spatter produced in the initial welding step be low-level spatter (which may hereinafter be referred to as minor spatter). Since the occurrence of spatter reduces interelectrode resistance, a voltage drop appears as a measured value when a voltage between electrodes is measured in resistance spot welding. In accordance with aspects of the present invention, the level of spatter can be controlled by controlling the amount of voltage drop at the occurrence of spatter. Specifically, the current value and the welding force in the initial welding step are preferably set such that an interelectrode voltage (welding voltage) Vs (V) at the time of occurrence of spatter …” (emphasis added). It is submitted that the aforementioned description provided in the written description of the instant patent application is equivalent to the advantages that the primary prior art citation (Chikaumi) teaches: “(4) Once expulsion has occurred during welding due to the aforementioned disturbances such as a sheet gap or current shunting, molten metal splatters on the surroundings. Consequently, the sheet thickness of the weld decreases, and the voltage between electrodes decreases sharply. Hence, in the adaptive control welding, the instantaneous amount of heat generated per unit volume, which is calculated from the electrical property between the electrodes, decreases significantly, and such control that excessively increases the welding current or voltage in order to compensate for this will end up being performed. This facilitates further expulsion. (5) We conducted more study to prevent further expulsion in the case where expulsion has occurred during welding. We consequently discovered that further expulsion can be prevented to obtain a nugget of an appropriate diameter in the following manner: The current pattern is divided into two or more steps, to perform adaptive control welding. Moreover, a expulsion detector is provided. In the case where the detector detects expulsion during welding, the subsequent target amount of heat generated is reduced, and the current passage amount such as the welding current and the voltage between electrodes is adjusted based on the reduced target amount of heat generated. (6) To newly set the target amount of heat generated after expulsion, typically the amount of heat generated needs to be recalculated while taking into account the sheet thickness decreased upon expulsion. However, it is very difficult to accurately monitor the decrease of the sheet thickness during welding. We accordingly studied any alternative method of newly setting the target amount of heat generated after expulsion, and discovered that it is effective to reduce the subsequent target amount of heat generated depending on the degree of decrease in voltage between electrodes or resistance between electrodes upon expulsion detection.” (emphasis added) (see FIG. 1A-1C of Chikaumi herafter).
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Furthermore, the secondary citation (JFE) is cited for its teachings related to two distinct energization periods which promote hydrogen diffusion to improve the strength of a subject weld joint with the claimed timing related to the initial welding step (“main energization”, JFE) in relation to the main welding step (“post-energization”, JFE) of the correlated aforementioned limitations of JFE with that of claim 1 of the instant patent application (“By applying post-energization after welding energization (main energization) in the welding process and maintaining a high temperature state in which hydrogen easily diffuses, diffusion of hydrogen from the welded portion is promoted and delayed fracture resistance of the welded joint is improved. I understood that. In addition, it was found that by increasing the applied pressure in the post-energization process, it is possible to maintain the weld in a high temperature state and a large compressive stress state in which hydrogen is more easily discharged.”, JFE) (emphasis added)
With regard to claim 3, Chikaumi teaches a cooling step between the initial welding step and the main welding step, the cooling step being a step of welding at a current Ic (kA) satisfying relation (3): 0≤I c ≤I 1 (3) where Ic is a current (kA) in the cooling step and I1 is a current (kA) in the initial welding step (in Joint #1 at Table 2 a cooling time Tc is provided between the first step and the second step with the current value in the cooling time Tc being smaller than the current value in the first step to avoid scattering (pg. 3, ln. 54-58)).
With regard to claim 5, Chikaumi teaches a welding voltage Vs (V) at the time of occurrence of the spatter satisfies relation (4): Vs≥0.7×Va (4) where Va is a welding voltage (V) 5 ms before occurrence of the spatter, and Vs is a welding voltage (V) at the time of occurrence of the spatter (in Joint #1 and 6 of Table 2 the decrease rate in the inter-electrode voltage per 1 cycle (50 Hz)(i.e, per 20 ms) when generation of expulsion is detected is 20% and 25% (I*R=V); therefore, the welding voltage at the point in time of generation of expulsion is greater than 0.7 times the welding voltage 5 ms before the generation of expulsion).
With regard to claim 7, Chikaumi teaches a welding voltage Vs (V) at the time of occurrence of the spatter satisfies relation (4): Vs≥0.7×Va (4) where Va is a welding voltage (V) 5 ms before occurrence of the spatter, and Vs is a welding voltage (V) at the time of occurrence of the spatter (in Joint #1 and 6 of Table 2 the decrease rate in the inter-electrode voltage per 1 cycle (50 Hz)(i.e, per 20 ms) when generation of expulsion is detected is 20% and 25% (I*R=V); therefore, the welding voltage at the point in time of generation of expulsion is greater than 0.7 times the welding voltage 5 ms before the generation of expulsion).
With regard to claim 9, Chikaumi teaches a method for producing a resistance spot weld joint using the resistance spot welding method according to claim 1 (“A resistance spot welding method in which a material to be welded in which a plurality of metal plates are superimposed is sandwiched between a pair of electrodes and energized while being pressurized to perform joining”, CL. 1).
With regard to claim 11, Chikaumi teaches a method for producing a resistance spot weld joint using the resistance spot welding method according to claim 3 (“A resistance spot welding method in which a material to be welded in which a plurality of metal plates are superimposed is sandwiched between a pair of electrodes and energized while being pressurized to perform joining”, CL. 1).
With regard to claim 13, Chikaumi teaches a method for producing a resistance spot weld joint using the resistance spot welding method according to claim 5 (“A resistance spot welding method in which a material to be welded in which a plurality of metal plates are superimposed is sandwiched between a pair of electrodes and energized while being pressurized to perform joining”, CL. 1).
With regard to claim 15, Chikaumi teaches a method for producing a resistance spot weld
joint using the resistance spot welding method according to claim 7 (“A resistance spot welding method in which a material to be welded in which a plurality of metal plates are superimposed is sandwiched between a pair of electrodes and energized while being pressurized to perform joining”, CL. 1).
Response to Arguments
Applicant’s arguments with respect to the claims have been considered but are moot in view of the newly presented prior art rejection in view of the newly presented claim amendments.
The instant patent application recites in independent claim 1 an initial welding step and a main
welding step with spatter being produced within 40 ms in the initial welding step. As an initial matter, it is submitted that the written description of the instant patent application explicitly states that: “In accordance with aspects of the present invention, it is preferable to produce spatter within 200 ms of the start of welding in the initial welding step. It is more preferable to produce spatter within 100 ms of the start of welding in the initial welding step. The minimum time from the start of welding to the occurrence of spatter is not limited to a particular length, but it is preferable that it be 20 ms or more.” Accordingly, in view of the aforementioned explicit teaching from the written description of the instant patent application, it is submitted that the claimed limitation of 40 ms of spatter discharge occurring in the initial welding step is not critical to the instant invention of independent claim 1 of the instant patent application in view of the explicit teachings of the written description. Notwithstanding the foregoing, as detailed in the obviousness rejection, the secondary citation citation (JFE) teaches at Table 1-2 a sample 40 which teaches an initial energization time (ta) of 80-120 ms and a pressurization delay (tb) of 40 ms. Additionally, as the primary prior art citation (Chikaumi) teaches the claimed values of relations (1) and (2) of claim 1 of the instant patent application as detailed above in combination with the aforementioned explicit non-criticality, it is submitted that such a limitation would have been obvious before the effective date of the claimed invention to one of ordinary skill in the art as a matter of routine experimentation to achieve a desired weld-strength of a formed nugget. However, assuming it was determined that the secondary prior art citation did not teach the limitations as detailed above, it would have been obvious before the effective date of the claimed invention to one of ordinary skill in the art to modify the timing of the initial welding step as a matter of routine experimentation as the primary citation (Chikaumi) teaches at FIG. 1A a voltage application between electrodes (kv) until an expulsion occurs (plotted against welding time in cycles), and upon detection of expulsion, the voltage is reduced as illustrated in FIG. 1A (as reproduced hereafter). Furthermore, this figure of Chikaumi details a primary advantage/result of the invention of claim 1 of the instant patent application related to controlling the level of spatter by controlling the amount of voltage drop at the occurrence of spatter (see written description of the instant patent application at para. [0047]: “To stably form a large diameter nugget in the main welding step described below, it is preferable that the spatter produced in the initial welding step be low-level spatter (which may hereinafter be referred to as minor spatter). Since the occurrence of spatter reduces interelectrode resistance, a voltage drop appears as a measured value when a voltage between electrodes is measured in resistance spot welding. In accordance with aspects of the present invention, the level of spatter can be controlled by controlling the amount of voltage drop at the occurrence of spatter. Specifically, the current value and the welding force in the initial welding step are preferably set such that an interelectrode voltage (welding voltage) Vs (V) at the time of occurrence of spatter …” (emphasis added). It is submitted that the aforementioned description provided in the written description of the instant patent application is equivalent to the advantages that the primary prior art citation (Chikaumi) teaches: “(4) Once expulsion has occurred during welding due to the aforementioned disturbances such as a sheet gap or current shunting, molten metal splatters on the surroundings. Consequently, the sheet thickness of the weld decreases, and the voltage between electrodes decreases sharply. Hence, in the adaptive control welding, the instantaneous amount of heat generated per unit volume, which is calculated from the electrical property between the electrodes, decreases significantly, and such control that excessively increases the welding current or voltage in order to compensate for this will end up being performed. This facilitates further expulsion. (5) We conducted more study to prevent further expulsion in the case where expulsion has occurred during welding. We consequently discovered that further expulsion can be prevented to obtain a nugget of an appropriate diameter in the following manner: The current pattern is divided into two or more steps, to perform adaptive control welding. Moreover, a expulsion detector is provided. In the case where the detector detects expulsion during welding, the subsequent target amount of heat generated is reduced, and the current passage amount such as the welding current and the voltage between electrodes is adjusted based on the reduced target amount of heat generated. (6) To newly set the target amount of heat generated after expulsion, typically the amount of heat generated needs to be recalculated while taking into account the sheet thickness decreased upon expulsion. However, it is very difficult to accurately monitor the decrease of the sheet thickness during welding. We accordingly studied any alternative method of newly setting the target amount of heat generated after expulsion, and discovered that it is effective to reduce the subsequent target amount of heat generated depending on the degree of decrease in voltage between electrodes or resistance between electrodes upon expulsion detection.” (emphasis added) (see FIG. 1A-1C of Chikaumi herafter).
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Furthermore, the secondary citation (JFE) is cited for its teachings related to two distinct energization periods which promote hydrogen diffusion to improve the strength of a subject weld joint with the claimed timing related to the initial welding step (“main energization”, JFE) in relation to the main welding step (“post-energization”, JFE) of the correlated aforementioned limitations of JFE with that of claim 1 of the instant patent application (“By applying post-energization after welding energization (main energization) in the welding process and maintaining a high temperature state in which hydrogen easily diffuses, diffusion of hydrogen from the welded portion is promoted and delayed fracture resistance of the welded joint is improved. I understood that. In addition, it was found that by increasing the applied pressure in the post-energization process, it is possible to maintain the weld in a high temperature state and a large compressive stress state in which hydrogen is more easily discharged.”, JFE) (emphasis added)
Conclusion
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/JOSEPH W ISKRA/Examiner, Art Unit 3761
/IBRAHIME A ABRAHAM/Supervisory Patent Examiner, Art Unit 3761
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