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 .
Response to Amendment
The proposed amendments filed on 05/13/2026 have been entered. Claims 1-21 are currently pending where claim 21 is newly added. Claim 8 appears to be the only amendment set forth.
Claim Rejections - 35 USC § 102
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 the appropriate paragraphs of 35 U.S.C. 102 that form the basis for the rejections under this section made in this Office action:
A person shall be entitled to a patent unless –
(a)(1) the claimed invention was patented, described in a printed publication, or in public use, on sale, or otherwise available to the public before the effective filing date of the claimed invention.
Claims 1, 2, 4, 6, 7, 10-15, and 17-19 are rejected under 35 U.S.C. 102(a)(1) as being anticipated by US 4494415 (Elliston hereinafter).
Regarding claim 1, Elliston teaches a power end of a high pressure pump that discloses a fluid end assembly (Fluid end at 26 in Figure 3); a modular power end assembly (Power end at 10 in Figure 3), comprising: a plurality of first stay rods (Stay rods 60); and a plurality of sections (Sections 150 and 138 in Figures 3 and 6), each section connected to one another via the plurality of first stay rods (Evident from Figures 3 and 6); and a plurality of second stay rods (Rods 44); in which the fluid end assembly is connected to the power end assembly via the plurality of second stay rods (Evident from Figure 3 with 44 connecting 26 to the power end 10).
Regarding claim 2, Elliston’s teachings are described above in claim 1 where Elliston further discloses that the plurality of first stay rods extends parallel to the plurality of second stay rods (Figure 3 shows the relationship between 60 and 44).
Regarding claim 4, Elliston’s teachings are described above in claim 1 where Elliston further discloses that each of the plurality of first stay rods extends parallel to a longitudinal axis of the power end assembly (Evident of Figure 3 with stay rods 60); in which each of the plurality of second stay rods extends parallel to the longitudinal axis of the power end assembly (Evident from stay rods 44 in Figure 3); in which each of the plurality of first stay rods is offset relative to a centerline axis of the power end assembly by a distance, D1 (Distance between the center axis along 84 in Figure 3 and the stay rods 60); and in which each of the plurality of second stay rods is offset relative to the centerline axis of the power end assembly by a distance, D2 (Distance between the center axis along 84 in Figure 3 and the stay rods 44).
Regarding claim 6, Elliston’s teachings are described above in claim 1 where Elliston further discloses that the plurality of sections comprises: a crank section comprising a crankshaft (Crank shaft at 138); a crosshead section comprising a plurality of crossheads (Crosshead assembly 150); and a rear support plate attached to the crank section (Rear support plate 112).
Regarding claim 7, Elliston’s teachings are described above in claim 6 where Elliston further discloses that the plurality of first stay rods traverses both the crank section and the crosshead section (Evident from Figure 3).
Regarding claim 10, Elliston’s teachings are described above in claim 1 where Elliston further discloses that the plurality of second stay rods passes through only a portion of the power end assembly (Evident from Figure 3 with second stay rods 44).
Regarding claim 11, Elliston teaches a power end of a high pressure pump as described above in claim 1 while showing a method of assembly that discloses connecting each section of the plurality of sections of the power end assembly together via the plurality of first stay rods (Connecting sections 150 and 138 via stay rods 60 in Figures 3 and 6); inserting a portion of the plurality of second stay rods into a portion of the power end assembly (Stay rod 44 in Figure 3); and connecting the fluid end assembly to the plurality of second stay rods such that the fluid end assembly is removably attached to the power end assembly (Fluid end connected to 20 via the stay rods 44 in Figure 3).
Regarding claim 12, Elliston’s teachings are described above in claim 1 where Elliston further discloses that each of the plurality of first stay rods traverses only a portion of the power end assembly (Under the broadest reasonable interpretation the stay rod 60 does not traverse the entire casing of the power end as seen in Figures 3 and 6).
Regarding claim 13, Elliston teaches a power end of a high pressure pump that discloses a power end assembly (Power end 10) secured together by a plurality of first stay rods (Stay rods 60 in Figures 3 and 6), each of the plurality of first stay rods traversing at least a portion of the power end assembly (Evident from Figures 3 and 6); wherein the power end assembly comprises an external surface having opposed first and second ends bound by an intermediate outer portion (Surface of 59); and a fluid end assembly coupled to the power end assembly using a plurality of second stay rods (Fluid end 26 with 20 connected to second stay rods 44 in Figure 3), each of the plurality of second stay rods projecting from the first end of the external surface of the power end assembly (Evident from Figure 3); in which each of the plurality of first stay rods is in a spaced relationship with each of the plurality of second stay rods (Under the broadest reasonable interpretation, the two sets of stay rods 60 and 44 are spaced from each other as seen in Figure 3).
Regarding claim 14, Elliston’s teachings are described above in claim 13 where Elliston further discloses that each of the plurality of first stay rods traverses the entire power end assembly (Under the broadest reasonable interpretation, the stay rods 60 span the entire power transfer power as seen in Figure 6 by ending at 112)
Regarding claim 15, Elliston’s teachings are described above in claim 13 where Elliston further discloses that the power end assembly further comprises: a longitudinal axis extending through both the first and second ends (Axis along 84 that travels through the power end in Figure 3); in which each of the plurality of first stay rods extends parallel to the longitudinal axis (Evident from Figure 3); and in which each of the plurality of second stay rods extends parallel to the longitudinal axis (Evident from Figure 3).
Regarding claim 17, Elliston’s teachings are described above in claim 13 where Elliston further discloses that the power end assembly further comprises a plurality of bearings (Bearings 114 in Figure 6); in which each of the plurality of first stay rods extends through the power end assembly by a length that is greater than a length by which each of the plurality of bearings extends through the power end assembly (Evident from Figure 6).
Regarding claim 18, Elliston’s teachings are described above in claim 13 where Elliston further discloses that the power end assembly further comprises: a crank section housing a crankshaft (Crank section 138); a crosshead section housing at least one crosshead (Crosshead 150); and a plate situated adjacent the crank section (Plate 111); in which the first end of the external surface is situated intermediate the second end of the external surface and the fluid end assembly (External surface of 59 in Figure 3); and in which the second end of the external surface is situated adjacent the plate (Evident from Figures 3 and 6).
Regarding claim 19, Elliston’s teachings are described above in claim 13 where Elliston further discloses a central support plate situated intermediate the crank section and the crosshead section (Plate 57); in which the plurality of first stay rods traverses the central support plate (Seen in Figures 3 and 6).
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 3, 5, and 8 are rejected under 35 U.S.C. 103 as being unpatentable over US 4494415 (Elliston) in view of US 6171070 (Mitake hereinafter).
Regarding claim 3, Elliston’s teachings are described above in claim 2 but are silent with respect that the plurality of first stay rods is vertically offset from the plurality of second stay rods.
However, Mitake teaches a high pressure reciprocating pump system that discloses a first set of stay rods (Stay rods 12 on the power end side), a second set of stay rods (Stay rods 11 on the fluid end side), and the plurality of first stay rods is vertically offset from the plurality of second stay rods (Figure 2 of Mitake). The resultant combination would separate the first and second stay rods of Elliston.
It would have been obvious to one of ordinary skill in the art before the effective filing date of the invention to modify the stay rods of Elliston with the offset stay rods of Mitake to allow for individual replacements of one set of stay rods without interacting with the other set of stay rods.
Regarding claim 5, Elliston’s teachings are described above in claim 4 but are silent with respect that D1 is greater than D2.
However, Mitake teaches a high pressure reciprocating pump system that discloses a first set of stay rods with a distance D1 from a center axis (Stay rods 12 on the power end side), a second set of stay rods with a distance D2 from the center axis (Stay rods 11 on the fluid end side), and the distance D1 is greater than D2 (Figure 2 of Mitake). The resultant combination would separate the first and second stay rods of Elliston.
It would have been obvious to one of ordinary skill in the art before the effective filing date of the invention to modify the stay rods of Elliston with the offset stay rods of Mitake to allow for individual replacements of one set of stay rods without interacting with the other set of stay rods.
Regarding claim 8, Elliston’s teachings are described above in claim 6 where Elliston further discloses that the crank section is situated intermediate the crosshead section and the rear support plate (Figures 3 and 6 of Elliston shows the order going the crosshead section at 150 then the crank section at 138 and followed by the rear support plate 112).
Elliston is silent with respect that the rear support plate comprises a plurality of blind openings; in which each opening of the plurality of blind openings is configured to receive a corresponding one of the plurality of first stay rods in a one-to-one relationship.
However, Mitake teaches a high pressure reciprocating pump system that discloses a first set of stay rods (Stay rods 12 on the power end side), a second set of stay rods (Stay rods 11 on the fluid end side), and a rear support plate comprises a plurality of blind openings; in which each opening of the plurality of blind openings is configured to receive a corresponding one of the plurality of first stay rods in a one-to-one relationship (Figure 2 of Mitake show that 11 inserts into 9a which the Examiner is seeing as having blind openings in a one to one relationship). The resultant combination would separate the first and second stay rods of Elliston.
It would have been obvious to one of ordinary skill in the art before the effective filing date of the invention to modify the stay rods of Elliston with the blind openings and stay rod assembly of Mitake to allow for individual replacements of one set of stay rods without interacting with the other set of stay rods.
Claims 9, 16, and 20 are rejected under 35 U.S.C. 103 as being unpatentable over US 4494415 (Elliston) in view of US 2018/0363642 (Salih hereinafter).
Regarding claim 9, Elliston’s teachings are described above in claim 1 but are silent with respect that the fluid end assembly is modular.
However, Salih teaches a fluid end of a reciprocating pump that discloses the use of a modular fluid end (Figure 1 with ¶ 32-34 and the Abstract).
It would have been obvious to one of ordinary skill in the art before the effective filing date of the invention to modify the fluid end of Elliston with the modular fluid end of Salih to allow for easy replacement and assembly of a fluid end.
Regarding claim 16, Elliston’s teachings are described above in claim 13 but are silent with respect that the fluid end assembly is modular.
However, Salih teaches a fluid end of a reciprocating pump that discloses the use of a modular fluid end (Figure 1 with ¶ 32-34 and the Abstract).
It would have been obvious to one of ordinary skill in the art before the effective filing date of the invention to modify the fluid end of Elliston with the modular fluid end of Salih to allow for easy replacement and assembly of a fluid end.
Regarding claim 20, Elliston teaches a power end of a high pressure pump that discloses a modular power end assembly secured together by a plurality of first stay rods (Power end 10 with stay rods 60), each of the plurality of first stay rods traversing at least a portion of the modular power end assembly (Evident from Figures 3 and 6); and a fluid end assembly coupled to the modular power end assembly using a plurality of second stay rods (Fluid end 26 with end at 20 attached via stay rods 44), each of the plurality of second stay rods projecting from an end of the modular power end assembly (Evident from Figure 3); in which each of the plurality of first stay rods is in a spaced-relationship with each of the plurality of second stay rods (Under the broadest reasonable interpretation, the two sets of stay rods 60 and 44 are spaced from each other as seen in Figure 3).
Elliston is silent with respect that the fluid end assembly is modular.
However, Salih teaches a fluid end of a reciprocating pump that discloses the use of a modular fluid end (Figure 1 with ¶ 32-34 and the Abstract).
It would have been obvious to one of ordinary skill in the art before the effective filing date of the invention to modify the fluid end of Elliston with the modular fluid end of Salih to allow for easy replacement and assembly of a fluid end.
Allowable Subject Matter
Claim 21 objected to as being dependent upon a rejected base claim, but would be allowable if rewritten in independent form including all of the limitations of the base claim and any intervening claims. Applicant has claim 21 clarify the specific structure of the modular power end in such a manner that Elliston could not be modified and still maintain the structure shown by Elliston. Therefore this claim is objected to as allowable for being non-obvious with respect to the Elliston reference cited above.
Response to Arguments
Applicant's arguments filed 05/13/2026 have been fully considered but they are not persuasive.
Applicant argues that the rejection of claim 1 by Elliston (US 4494415) fails to disclose that the power end is modular in nature. The Examiner disagrees with the Applicant in that they appear to be using a narrower definition/interpretation of modular that more closely aligns with their invention. The common definitions of modular relate to a construction with standardized units or dimension for flexibility and variety of use or being made from a set of separate parts that can be joined together to form a larger object. These definitions can both apply to Elliston in that the individual components are not described as custom and are seen to taken from stocks of standardized groups (i.e. standard bolt and nut sizes). Applicant is attempting to use modular to imply significantly more structure than claimed by forcing the Examiner to read the specification into the claim. Applicant’s Figure 1 does show a modular power end however the specific sections are not claimed to be related to or are modular. Applicant does appear to clear this relationship up in the newly added, and objected to as allowable, claim 21. However, at this time, Applicant’s arguments directed towards the Elliston reference with respect to the modularity of the power end are not found to be persuasive.
Applicant’s argument regarding the amendment to claim 8 has been reviewed but is not found to be persuasive. Figures 3 and 6 of Elliston are quite clear in showing (From figure left of Figure 3 to figure right of Figure 3 and in the matching direction of Figure 6) the crank section at 138 being intermediate the crosshead section at 150 and the rear support plate 112.
Applicant’s argument regarding claim 10 and the interpretation of the second stay rods passing though only a portion of the power end assembly has been reviewed but is not found to be persuasive. The Elliston references teaches the second stay rods 44 in Figure 3 which pass through a portion of the power end assembly by passing through a portion of frame which is the crosshead assembly at 150, particularly around the frame that houses the pony/crosshead rod 84 as seen in Figure 3 of Elliston. For at least this reason, Applicant’s argument is not found to be persuasive.
Applicant’s argument regarding claim 14 and the interpretation that the first stay rods traverse the entire power end assembly has been reviewed but is not found to be persuasive. Elliston states “The bearing caps 112 are retained in assembly with the blocks 111 by the tie rods 60 and respective associated retaining nuts 63.” on Page 6 Lines 27-29 where this relationship is shown clearly in Figures 3 and 6. Applicant argues that the stay rods 60 do not traverse the removable cover 110 however no such cover is mentioned by Elliston. Elliston does show a removable cover 100 which the Examiner is assuming this was what was intended by the Applicant. However, this component (100) of Elliston was not relied on due to the specific wording of the claims as set forth by Applicant. Therefore, Applicant’s argument regarding claim 14 is not found to be persuasive.
Applicant’s argument regarding claim 18 and the interpretation of “a plate situated adjacent the crank section; in which the first end of the external surface is situated intermediate the second end of the external surface and the fluid end assembly; and in which the second end of the external surface is situated adjacent the plate” has been reviewed but is not found to be persuasive. Applicant initially argues that the rejection of claim 13 is unclear as to which end is the first end and which end is the second end. The first end will be towards the cylinder assembly at 26 and the second end will be towards the crank section 168. Therefore, Elliston shows, as rejected above, the plate (111 as best seen in Figure 6) adjacent to the crank section and which the first end of the external surface is situated intermediate the second end of the external surface and the fluid end assembly (External surface of 59 in Figure 3 is between the described first end and the described second end); and in which the second end of the external surface is situated adjacent the plate (Evident from Figures 3 and 6 with 59’s second end being adjacent but not abutting the plate 111). Applicant has room to amend this limitation to overcome the outlined interpretation above and the Examiner is open to discussions if they would like to pursue this route. However, at this time, Applicant’s arguments regarding claim 18 are not found to be persuasive.
Applicant’s argument regarding the combination of Elliston and Salih has been reviewed but is not found to be persuasive. Applicant argues that the Silah reference fails to disclose a modular power end. The Silah reference was not relied upon to teach the aforementioned limitation and therefore Applicant’s argument regarding the combination of the Elliston and Silah reference is not found to be persuasive.
Applicant’s argument regarding claim 20 and the limitation of “in which each of the plurality of first stay rods is in a spaced-relationship with each of the plurality of second stay rods” has been reviewed but it is not found to be persuasive. Applicant appears to be taking a narrow interpretation of their intended meaning of “spaced-relationship” by having the two sets of stay rods to be vertically or horizontally offset from each other. However, the Examiner is taking the broadest reasonable interpretation into consideration and in Figure 3 of Elliston the two sets of stay rods are in fact spaced apart from each other. Applicant is welcome to further amend the claim to clarify what is exactly intended by the phrase “spaced-relationship”. However, Applicant’s argument regarding claim 20 is not found to be persuasive.
Conclusion
THIS ACTION IS MADE FINAL. Applicant is reminded of the extension of time policy as set forth in 37 CFR 1.136(a).
A shortened statutory period for reply to this final action is set to expire THREE MONTHS from the mailing date of this action. In the event a first reply is filed within TWO MONTHS of the mailing date of this final action and the advisory action is not mailed until after the end of the THREE-MONTH shortened statutory period, then the shortened statutory period will expire on the date the advisory action is mailed, and any nonprovisional extension fee (37 CFR 1.17(a)) pursuant to 37 CFR 1.136(a) will be calculated from the mailing date of the advisory action. In no event, however, will the statutory period for reply expire later than SIX MONTHS from the mailing date of this final action.
Any inquiry concerning this communication or earlier communications from the examiner should be directed to CONNOR J. TREMARCHE whose telephone number is (571)272-2175. The examiner can normally be reached Monday - Thursday 0700-1700 Eastern.
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/CONNOR J TREMARCHE/Primary Examiner, Art Unit 3762
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