DETAILED ACTION
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and the fee set forth in 37 CFR 1.17(e) has been timely paid, the finality of the previous Office action has been withdrawn pursuant to 37 CFR 1.114.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 February 16, 2026 has been entered.
Response to Amendment
The Amendment filed February 16, 2026 has been entered. Claims 1, 3 – 15 and 18 – 20 are pending in the application with claims 2, 16 and 17 being cancelled.
Claim Rejections - 35 USC § 102
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, 3, 4, 10 – 13 and 18 – 20 are rejected under 35 U.S.C. 102(a)(1) as being anticipated by Elliston, Thomas (US 4,494,415 – herein after Elliston).
In reference to claim 1, Elliston discloses a positive displacement reciprocating pump (10, see fig. 1) comprising (see figs. 3-4):
a crank member (120+130, see fig. 7) rotatable about a central axis (134/132, see fig. 3); and
a wrist pin assembly (assembly formed of components 141, 70, 148, 150, 157, 156; see fig. 3) pivotably coupled (via 141, see fig. 7) to the crank member (120+130), the wrist pin assembly
operable to translate in a first direction (in view of fig. 4: “first direction” being in ↓ direction) and a second direction (in view of fig. 4: “second direction” being in ↑ direction) as the crank member rotates, the wrist pin assembly including:
a wrist pin (148);
a plunger assembly (assembly comprising of 84+80+82+81) directly coupled to the wrist pin assembly (see fig. 4: component 84 of the plunger assembly is seen “directly coupled” to component 156 of the wrist pin assembly), the plunger assembly translates along a central axis (in view of fig. 4: “central axis” being in ↨ direction or in view of fig. 3: “central axis” being in ↔ direction) in the first direction and the second direction as the crank member rotates, the plunger assembly including:
a pony rod (84) coupled to an attachment interface (interface defined by components 157+156) extending radially from the wrist pin (148) [in view of fig. 4: axial direction of the wrist pin is considered to be in ↔ direction while radial direction of the wrist pin is in considered to be in ↨ direction], such that the pony rod (84) is directly connected to the wrist pin (148) [as evident from fig. 4: pony rod 84 is seen as being “directly coupled” to the interface 157+156 of the wrist pin 148]; and
a pump section (26, see fig, 1) pressurized by the plunger assembly moving in the first direction (viewed as ← direction in view of fig. 1) and depressurized by the plunger assembly moving in the second direction (viewed as → direction in view of fig. 1);
a connecting rod (141) pivotably attached to the crank member (120+130);
a housing (70) extending between a crank member end (end closer to the crank member; in view of fig. 4: this end being a top end of 70) and a piston rod end (end closer to the piston rod; in view of fig. 4: this end being a bottom end of 70), the connecting rod (141) extending from the crank member (120+130) and into the housing (70) through the crank member end (top end of 70); and
a crosshead (150) installed within the housing (70), the crosshead (120+130) operable to translate (see col. 7, lines 62-65) within the housing (70) between the crank member end (top end of 70) and the piston rod end (bottom end of 70);
wherein the wrist pin (148) is installed within the crosshead (150), the connecting rod (141) pivotably attached to the wrist pin to translate the wrist pin and the crosshead within the housing in the first direction (in view of fig. 4: “first direction” being in ↓ direction) and the second direction (in view of fig. 4: “second direction” being in ↑ direction) as the crank member rotates.
In reference to claim 3, Elliston discloses the positive displacement reciprocating pump, wherein the connecting rod (141) comprises (see figs. 3-4):
a crank side section (top section in view of fig. 4) comprising:
a crank side attachment interface (top surface) configured to attach the connecting rod (141) to the crank member (120+130); and
a wrist pin side section (bottom section in view of fig. 4), the wrist pin side section opposite the crank side section, the connecting rod (141) extending longitudinally between the crank side section and the wrist pin side section (extending in ↨ in view of fig. 4), the wrist pin side section comprising: a wrist pin side attachment interface (bore that receives the wrist pin 148).
In reference to claim 4, Elliston discloses the positive displacement reciprocating pump, wherein the wrist pin (148) is installed into the wrist pin side attachment interface to couple the wrist pin to the crosshead (150).
In reference to claim 10, Elliston discloses the positive displacement reciprocating pump, wherein the connecting rod (141), the housing (70), the crosshead (150), and the plunger assembly (assembly comprising of 84+80+82+81) are installed substantially horizontally (rotate fig. 3 by 90° in clockwise direction: the claimed components being installed in claimed horizontal/axial direction of the pump is taught).
In reference to claim 11, Elliston discloses a wrist pin assembly (assembly comprising of following claimed elements) comprising (see figs. 3-4):
a connecting rod (141) pivotably attached to a crank member (120+130);
a housing (70) extending between a crank member end (end closer to the crank member; in view of fig. 4: this end being a top end of 70) and a piston rod end (end closer to the piston rod; in view of fig. 4: this end being a bottom end of 70), the connecting rod (141) extending from the crank member (120+130) and into the housing (70) through the crank member end (top end of 70);
a crosshead (150) installed within the housing (70), the crosshead (120+130) operable to translate (see col. 7, lines 62-65) within the housing (70) between the crank member end (top end of 70) and the piston rod end (bottom end of 70);
a wrist pin (148) installed within the crosshead (150), the connecting rod pivotably attached to the wrist pin to translate the wrist pin and the crosshead within the housing in a first direction (in view of fig. 4: “first direction” being in ↓ direction) and a second direction (in view of fig. 4: “second direction” being in ↑ direction) as the crank member rotates, wherein the wrist pin (148) comprises: a pony rod attachment interface (interface defined by components 157+156) extending radially therefrom (in view of fig. 4: axial direction of the wrist pin is considered to be in ↔ direction while radial direction of the wrist pin is in considered to be in ↨ direction); and
a plunger assembly (assembly comprising of 84+80+82+81) directly coupled to the wrist pin (see fig. 4: component 84 is seen “directly coupled” to the interface 157+156 of the wrist pin 148) and extending from the wrist pin through the piston rod end (bottom end of 70) [in view of fig. 4: the asserted plunger assembly extends in ↓ direction], the plunger assembly translates along a central axis (in view of fig. 4: “central axis” being in ↨ direction or in view of fig. 3: “central axis” being in ↔ direction) in the first direction and the second direction as the crank member rotates, wherein the plunger assembly comprises: a pony rod (84) directly coupled (see fig. 4) to the pony rod attachment interface (157+156) of the wrist pin (148), the pony rod operable to translate in the first direction (in view of fig. 4: “first direction” being in ↓ direction) and the second direction (in view of fig. 4: “first direction” being in ↑ direction) along a longitudinal axis (in view of fig. 4: axis being in ↨ direction) of the pony rod as the crank member rotates.
In reference to claim 12, Elliston discloses the wrist pin assembly, wherein the connecting rod (141) comprises (see figs. 3-4):
a crank side section (top section in view of fig. 4) comprising:
a crank side attachment interface (top surface) configured to attach the connecting rod (141) to the crank member (120+130); and
a wrist pin side section (bottom section in view of fig. 4), the wrist pin side section opposite the crank side section, the connecting rod (141) extending longitudinally between the crank side section and the wrist pin side section (extending in ↨ in view of fig. 4), the wrist pin side section comprising: a wrist pin side attachment interface (bore that receives the wrist pin 148).
In reference to claim 13, Elliston discloses the wrist pin assembly, wherein the wrist pin (148) is installed into the wrist pin side attachment interface to couple the wrist pin to the crosshead (150).
In reference to claim 18, Elliston discloses the wrist pin assembly, wherein the plunger assembly (assembly comprising of 84+80+82+81) comprises:
a piston rod (82) removably coupled to the pony rod (84) [in view of disclosure in col. 5, lines 3-37: coupling 80 that is present between piston rod 82 and pony rod 84 is removable] opposite (in view of fig. 4: opposite in ↓ direction) the pony rod attachment interface (157+156) of the wrist pin (148), the piston rod extending and retracting with the pony rod; and a clamp (80) configured to couple the piston rod (82) to the pony rod (84).
In reference to claim 19, Elliston discloses the wrist pin assembly, wherein the connecting rod (141), the housing (70), the crosshead (150), and the plunger assembly (assembly comprising of 84+80+82+81) are installed substantially horizontally (rotate fig. 3 by 90° in clockwise direction: the claimed components being installed in claimed horizontal/axial direction of the pump is taught).
In reference to claim 20, Elliston discloses the wrist pin assembly, wherein the housing (70) is fluidically sealed (in view of presence of seal 160; see col. 8, line 17 and fig. 3).
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.
The factual inquiries for establishing a background for determining obviousness under 35 U.S.C. 103 are summarized as follows:
1. Determining the scope and contents of the prior art.
2. Ascertaining the differences between the prior art and the claims at issue.
3. Resolving the level of ordinary skill in the pertinent art.
4. Considering objective evidence present in the application indicating obviousness or nonobviousness.
Claims 5 – 9, 14 and 15 are rejected under 35 U.S.C. 103 as being unpatentable over Elliston in view of Doman, David (US 4,977,817 – herein after Doman).
In reference to claim 5, Elliston teaches the positive displacement reciprocating pump, wherein the crosshead (150) is hollow such that the wrist pin side section (bottom section) of the connecting rod (141) is configured to fit within the crosshead.
Elliston remains silent on the positive displacement reciprocating pump, wherein the crosshead comprises of first and second apertures and their claimed arrangement.
However, Doman teaches a positive displacement reciprocating pump (see fig. 1), wherein a crosshead (602; see figs. 5-7) comprising:
a first aperture (707; labelled “h1” in fig. A below); and
a second aperture (707; labelled “h2” in fig. A below), the first aperture concentrically aligned with the second aperture such that a vertical axis (see fig. A below: labelled “v.a.”) of the first aperture and the second aperture are orthogonal to a central axis of the crosshead (see fig. A below: labelled “c.a.”).
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Fig. A: Edited fig. 7 of Doman to show claim interpretation.
Doman’s crosshead 602 is equivalent to Elliston’s crosshead 150. Doman’s insert 702 is equivalent to Elliston’s part 156. Doman’s cross-shaft 706 is equivalent to Elliston’s pin 148. Doman’s housing 502 is equivalent to Elliston’s sleeve 70. Thus, it would have been obvious to the person of ordinary skill in the art before the effective filing date of the invention to modify Elliston’s components (150, 156, 148, 70) for having the crosshead assembly as taught by Doman because “In this way, modifications are made to the instantaneous output of the pump to largely eliminate or substantially reduce undesirable flow fluctuations”, as recognized by Doman (see col. 3, lines 53-57).
In reference to claim 6, Elliston, as modified above in claim 5, teaches the positive displacement reciprocating pump, wherein at least a portion of the wrist pin (viewed as 705 in fig. A above) extends into the first aperture (viewed as 707 or “h1” in fig. A above) and the second aperture (viewed as 707 or “h2” in fig. A above) when the wrist pin is installed within the crosshead (viewed as 602 in fig. A above).
In reference to claim 7, Elliston, as modified above in claim 6, teaches the positive displacement reciprocating pump, wherein the wrist pin comprises: a pony rod attachment interface (interface defined by 157+156 for “pony rod”, in Elliston) extending radially therefrom (this is the interface to which pony rod 84 of Elliston is coupled to).
In reference to claim 8, Elliston, as modified above in claim 7, teaches the positive displacement reciprocating pump, wherein the pony rod (viewed as 84 in Elliston) is coupled to the pony rod attachment interface (157+156, in Elliston) of the wrist pin (148, in Elliston), the pony rod operable to translate in the first direction (in view of Elliston’s fig. 4: “first direction” being in ↓ direction) and the second direction (in view of Elliston’s fig. 4: “first direction” being in ↑ direction) along a longitudinal axis (in view of Elliston’s fig. 4: axis being in ↨ direction) of the pony rod as the crank member rotates.
In reference to claim 9, Elliston, as modified above in claim 8, teaches the positive displacement reciprocating pump, wherein the plunger assembly comprises:
a piston rod (82; in Elliston) removably coupled to the pony rod (84; in Elliston) opposite (in view of Elliston’s fig. 4: opposite in ↓ direction) the pony rod attachment interface (157+156; in Elliston), the piston rod extending into the pump section to pressurize and depressurize the pump section (in Elliston); and a clamp (80; in Elliston) configured to couple the piston rod to the pony rod.
In reference to claim 14, Elliston teaches the wrist pin assembly, wherein the crosshead (150) is hollow such that the wrist pin side section (bottom section) of the connecting rod (141) is configured to fit within the crosshead.
Elliston remains silent on the wrist pin assembly, wherein the crosshead comprises of first and second apertures and their claimed arrangement.
However, Doman teaches a positive displacement reciprocating pump (see fig. 1), wherein a crosshead (602; see figs. 5-7) comprising:
a first aperture (707; labelled “h1” in fig. A above); and
a second aperture (707; labelled “h2” in fig. A above), the first aperture concentrically aligned with the second aperture such that a vertical axis (see fig. A above: labelled “v.a.”) of the first aperture and the second aperture are orthogonal to a central axis of the crosshead (see fig. A above: labelled “c.a.”).
Doman’s crosshead 602 is equivalent to Elliston’s crosshead 150. Doman’s insert 702 is equivalent to Elliston’s part 156. Doman’s cross-shaft 706 is equivalent to Elliston’s pin 148. Doman’s housing 502 is equivalent to Elliston’s sleeve 70. Thus, it would have been obvious to the person of ordinary skill in the art before the effective filing date of the invention to modify Elliston’s components (150, 156, 148, 70) for having the crosshead assembly as taught by Doman because “In this way, modifications are made to the instantaneous output of the pump to largely eliminate or substantially reduce undesirable flow fluctuations”, as recognized by Doman (see col. 3, lines 53-57).
In reference to claim 15, Elliston, as modified, teaches the wrist pin assembly, wherein at least a portion of the wrist pin (viewed as 705 in fig. A above) extends into the first aperture (viewed as 707 or “h1” in fig. A above) and the second aperture (viewed as 707 or “h2” in fig. A above) when the wrist pin is installed within the crosshead (viewed as 602 in fig. A above).
Response to Arguments
Applicant's arguments filed February 16, 2026 have been fully considered but they are not persuasive.
With respect to independent claims 1 and 11, the reference of Elliston has been re-evaluated and re-applied in view of the amendment made to the independent claims. The limitations “plunger assembly”, “pony rod” and “attachment interface” or “pony rod attachment interface” have a new interpretation. In Elliston, “plunger assembly” is assembly formed of components 84+80+82+81, “pony rod” is component 84 and “attachment interface” or “pony rod attachment interface” is interface formed by components 157, 156. This attachment interface extends “radially” from the wrist pin 148 in same manner as that of applicant’s attachment interface 172 from the wrist pin 132.
With respect to arguments presented for Doman, the rejection of the claims relies upon a second embodiment (figs. 5-7) of Doman. Furthermore, Elliston teaches the argued limitation of the pony rod coupled to the wrist pin. Doman is relied upon to teach the provision of apertures in the crosshead. It is to be that one cannot show nonobviousness by attacking references individually where the rejections are based on combinations of references. See In re Keller, 642 F.2d 413, 208 USPQ 871 (CCPA 1981); In re Merck & Co., 800 F.2d 1091, 231 USPQ 375 (Fed. Cir. 1986).
Conclusion
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/CHIRAG JARIWALA/Examiner, Art Unit 3746
/ESSAMA OMGBA/Supervisory Patent Examiner, Art Unit 3746