Prosecution Insights
Last updated: April 19, 2026
Application No. 18/131,669

POSITIVE DISPLACEMENT PUMP MATERIAL DELIVERY SYSTEM FOR ADDITIVE MANUFACTURE

Non-Final OA §102§103
Filed
Apr 06, 2023
Examiner
GRAHAM, ANDREW D
Art Unit
1742
Tech Center
1700 — Chemical & Materials Engineering
Assignee
UNIVERSITY OF DELAWARE
OA Round
3 (Non-Final)
60%
Grant Probability
Moderate
3-4
OA Rounds
3y 8m
To Grant
82%
With Interview

Examiner Intelligence

Grants 60% of resolved cases
60%
Career Allow Rate
218 granted / 363 resolved
-4.9% vs TC avg
Strong +22% interview lift
Without
With
+22.1%
Interview Lift
resolved cases with interview
Typical timeline
3y 8m
Avg Prosecution
31 currently pending
Career history
394
Total Applications
across all art units

Statute-Specific Performance

§101
0.5%
-39.5% vs TC avg
§103
54.8%
+14.8% vs TC avg
§102
18.6%
-21.4% vs TC avg
§112
20.6%
-19.4% vs TC avg
Black line = Tech Center average estimate • Based on career data from 363 resolved cases

Office Action

§102 §103
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 . Claims 1-11, 18, and 20-24 are pending and under examination. Claims 12-17 are withdrawn. 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and the fee set forth in 37 CFR 1.17(e) has been timely paid, the finality of the previous Office action has been withdrawn pursuant to 37 CFR 1.114.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 3/16/2026 has been entered. 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 1-11, 20, and 22-23 are rejected under 35 U.S.C. 102(a)(1) as being anticipated by Fritsch (US Patent No. 3,649,147). Regarding claim 1, Fritsch discloses a positive displacement pump (gear pump) comprising: (a) a motor having a rotatable output shaft [while this feature is not explicitly disclosed, it is understood to be inherently present as to control conveyor screw (6)] (2:45-2:48); (b) at least one rotatable screw (6) that is attached to the output shaft of the motor [inherent as outlined above] (2:45-2:48) and disposed within a first portion of a housing (‘sleeve or drum (5)’ 2:48); and (c) a passage (20) defined downstream of said rotatable screw in a second portion of the housing (as illustrated in Fig. 1) that is configured to receive, heat using fluid ducts (8) (3:5-3:7; Fig. 1), and expel heated material out of the pump at (21). Fritsch further discloses with a linkage (36) and a block (37) in a diagram, that “such regulation may be automatically effected by a control means suitable and conventional for the purpose” (Fritsch, 2:55-2:58) which seems to describe an electrical connection to a controller to control the rotation of the output shaft. The limitations regarding the flow rate being proportional to a rotation rate of the output shaft . . . are not considered limiting here as a manner of operating the claimed device. However, the pressure sensor would allow for continuous operation in any conditions as the screw and feed can be manipulated in accordance with the pressure sensor (9, 36, 37) (see 2:49-2:58) as to allow for a constant flow rate in any pressure conditions. Please see the “response to arguments” section below for a further discussion of this limitation. Regarding claims 2, 4, 6, and 22, Fritsch discloses the subject matter of claim 1, and further discloses that the heating occurs in the downstream region using fluid ducts (8) (3:5-3:7) and not in the upstream region corresponding with the screw, and the screw is within a sleeve or drum (5) (2:45-2:48) which is a housing having a hollow region surrounding the screw (6). This would also mean that it occurs in the “second region” and not in the “first region” where the screw is located as is required in new claim 22. Regarding claim 3, Fritsch discloses the subject matter of claim 1, and further discloses that there is a nozzle (“lip” 4 and “exit slit” 21) (2:20-2:25) at an outlet of the passage. It is noted that the reference refers to the entire construction as a “nozzle” but this does not read upon the same element as in the claim, it is the combination of the “lip” and “exit slit” as outlined above which would map to the claimed “nozzle” at the outlet of the passage. *The limitation of “the nozzle positioned to deposit material exiting the nozzle onto an ever growing substrate that is a product of AM” is not considered limiting as it is an intended use. See MPEP 2114. Regarding claim 5, Fritsch discloses the subject matter of claim 1, and it is noted that “its length” is not defined and “a passage” can read upon a portion of the passage downstream from the screw as shown in Fig. 1. There is a portion of this passage with a constant cross-section. Regarding claim 7, Fritsch discloses the subject matter of claim 6, and further discloses that there is a guide (‘feed port 30’) (2:37-2:48) for directing the material into the gap between the screw and the housing. Regarding claim 8, Fritsch discloses the subject matter of claim 1, and further discloses the gear pump (2:59-2:75) that is made up of two gears (1, 2) that mesh together (see Fig. 1) Regarding claims 9-10, Fritsch discloses the subject matter of claim 1, and further discloses (Fig. 1) that the rotatable screw has no more than 4 turns and is conical in shape at the end as illustrated (Fig. 1). Regarding claim 11, Fritsch discloses the subject matter of claim 1, but does not appear to explicitly disclose that the length of the passage is defined by the equation in claim 11. However, Examiner notes that this limitation is interpreted in view of the instant specification, which provides that this equation comes from a textbook, meaning that this knowledge would be generally attributable to one of ordinary skill in the art before the effective filing date of the claimed invention. Furthermore, the equation depends on elements such as “a volumetric flow rate of a material”; “a thermal diffusivity of a material”; meaning that this is limited by its mode of operation, which is not considered limiting to an apparatus claim. See MPEP 2114. The specific material or article worked upon by a claimed structure is also generally not considered limiting. See MPEP 2115. Regarding claim 20, Fritsch discloses the subject matter of claim 18, and the gear pump is read as a static mixer positioned within the passage as to make a homogenous mixture prior to deposition (2:59-2:75). Regarding claim 23, Fritsch discloses the subject matter of claim 22, and further discloses the heater comprises “one or more . . . heating elements” (3:5-3:7) (the fluid ducts would be “heating elements”). 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. This application currently names joint inventors. In considering patentability of the claims the examiner presumes that the subject matter of the various claims was commonly owned as of the effective filing date of the claimed invention(s) absent any evidence to the contrary. Applicant is advised of the obligation under 37 CFR 1.56 to point out the inventor and effective filing dates of each claim that was not commonly owned as of the effective filing date of the later invention in order for the examiner to consider the applicability of 35 U.S.C. 102(b)(2)(C) for any potential 35 U.S.C. 102(a)(2) prior art against the later invention. Claims 1-11, 20, and 22-23 are rejected under 35 U.S.C. 103 as being unpatentable over Fritsch (US Patent No. 3,649,147) in view of Nishikawa (US 2015/0068667). Regarding claim 1, Fritsch discloses a positive displacement pump (gear pump) comprising: (a) a motor having a rotatable output shaft [while this feature is not explicitly disclosed, it is understood to be inherently present as to control conveyor screw (6)] (2:45-2:48); (b) at least one rotatable screw (6) that is attached to the output shaft of the motor [inherent as outlined above] (2:45-2:48) and disposed within a first portion of a housing (; and (c) a passage (20) defined downstream of said rotatable screw that is configured to receive, heat using fluid ducts (8) (3:5-3:7; Fig. 1), and expel heated material out of the pump at (21). Fritsch further discloses with a linkage (36) and a block (37) in a diagram, that “such regulation may be automatically effected by a control means suitable and conventional for the purpose” (Fritsch, 2:55-2:58) which seems to describe an electrical connection to a controller to control the rotation of the output shaft. The limitations regarding the flow rate being proportional to a rotation rate of the output shaft . . . are not considered limiting here as a manner of operating the claimed device. However, the pressure sensor would allow for continuous operation in any conditions as the screw and feed can be manipulated in accordance with the pressure sensor (9, 36, 37) (see 2:49-2:58). Additionally or alternatively to the above, the Fritsch reference may be read as not explicitly disclosing the motor having a rotatable output shaft in the claim above if it is not read as being inherent. However, Nishikawa discloses a similar apparatus to that of Fritsch, also designed to extrude plastic material through a die. Specifically, Nishikawa discloses a positive displacement pump comprising: (a) a motor having a rotatable output shaft (11d) (par. 0031); (b) at least one rotatable gear or rotatable screw (11c) that is attached to the output shaft of the motor (11d); and (c) a passage defined downstream (see Fig. 1) of the screw that is configured to receive and expel material out of the pump at a flow rate proportional to a rotation rate of the output shaft of the motor (defining the rotation of the screw) and at a constant flow rate (using first servo motor control as to control the gear pump defined by gears 12a). One of ordinary skill in the art would have found it obvious to have incorporated the motor of Nishikawa into the apparatus of Fritsch above as to likewise have operated the screw/pump elements as is required in the claims. Regarding claims 2, 4, 6, and 22, Fritsch/Nishikawa discloses the subject matter of claim 1, and further discloses that the heating occurs in the downstream region using fluid ducts (8) (F, 3:5-3:7) and not in the upstream region corresponding with the screw, and the screw is within a sleeve or drum (5) (2:45-2:48) which is a housing having a hollow region surrounding the screw (6). This would also mean that it occurs in the “second region” and not in the “first region” where the screw is located as is required in new claim 22. Regarding claim 3, Fritsch/Nishikawa discloses the subject matter of claim 1, and further discloses that there is a nozzle (“lip” 4 and “exit slit” 21) (F, 2:20-2:25) at an outlet of the passage. It is noted that the reference refers to the entire construction as a “nozzle” but this does not read upon the same element as in the claim, it is the combination of the “lip” and “exit slit” as outlined above. Regarding claim 5, Fritsch/Nishikawa discloses the subject matter of claim 1, and it is noted that “its length” is not defined and “a passage” can read upon a portion of the passage downstream from the screw as shown in Fig. 1. There is a portion of this passage with a constant cross-section. Regarding claim 7, Fritsch/Nishikawa discloses the subject matter of claim 6, and further discloses that there is a guide (‘feed port 30’) (F, 2:37-2:48) for directing the material into the gap between the screw and the housing. Regarding claim 8, Fritsch/Nishikawa discloses the subject matter of claim 1, and further discloses the gear pump (F, 2:59-2:75) that is made up of two gears (1, 2) that mesh together (see Fig. 1) Regarding claims 9-10, Fritsch/Nishikawa discloses the subject matter of claim 1, and further discloses (F, Fig. 1) that the rotatable screw has no more than 4 turns and is conical in shape at the end as illustrated (F, Fig. 1). Regarding claim 11, Fritsch/Nishikawa discloses the subject matter of claim 1, but does not appear to explicitly disclose that the length of the passage is defined by the equation in claim 11. However, Examiner notes that this limitation is interpreted in view of the instant specification, which provides that this equation comes from a textbook, meaning that this knowledge would be generally attributable to one of ordinary skill in the art before the effective filing date of the claimed invention. Furthermore, the equation depends on elements such as “a volumetric flow rate of a material”; “a thermal diffusivity of a material”; meaning that this is limited by its mode of operation, which is not considered limiting to an apparatus claim. See MPEP 2114. The specific material or article worked upon by a claimed structure is also generally not considered limiting. See MPEP 2115. Regarding claim 20, Fritsch/Nishikawa discloses the subject matter of claim 18, and the gear pump is read as a static mixer positioned within the passage as to make a homogenous mixture prior to deposition (F, 2:59-2:75). Regarding claim 23, Fritsch/Nishikawa discloses the subject matter of claim 22, and further discloses the heater comprises “one or more . . . heating elements” (F, 3:5-3:7) (the fluid ducts would be “heating elements”). Claim 18 is rejected under 35 U.S.C. 103 as being unpatentable over Fritsch (US Patent No. 3,649,147), alternatively in view of Nishikawa (US 2015/0068667), and further in view of Gerada et al. (US 2022/0097293), hereinafter Gerada. Regarding claim 18, Fritsch discloses a positive displacement pump (gear pump) comprising: (a) a motor having a rotatable output shaft [while this feature is not explicitly disclosed, it is understood to be inherently present as to control conveyor screw (6)] (2:45-2:48); (b) at least one rotatable screw (6) that is attached to the output shaft of the motor [inherent as outlined above] (2:45-2:48); and (c) a passage (20) defined downstream of said rotatable screw that is configured to receive, heat using fluid ducts (8) (3:5-3:7; Fig. 1), and expel heated material out of the pump at (21). The limitations regarding the flow rate being proportional to a rotation rate of the output shaft . . . are not considered limiting here as a manner of operating the claimed device. However, the pressure sensor would allow for continuous operation in any conditions as the screw and feed can be manipulated in accordance with the pressure sensor (9, 36, 37) (see 2:49-2:58). Additionally or alternatively to the above, the Fritsch reference may be read as not explicitly disclosing the motor having a rotatable output shaft in the claim above if it is not read as being inherent. However, Nishikawa discloses a similar apparatus to that of Fritsch, also designed to extrude plastic material through a die. Specifically, Nishikawa discloses a positive displacement pump comprising: (a) a motor having a rotatable output shaft (11d) (par. 0031); (b) at least one rotatable gear or rotatable screw (11c) that is attached to the output shaft of the motor (11d); and (c) a passage defined downstream (see Fig. 1) of the screw that is configured to receive and expel material out of the pump at a flow rate proportional to a rotation rate of the output shaft of the motor (defining the rotation of the screw) and at a constant flow rate (using first servo motor control as to control the gear pump defined by gears 12a). One of ordinary skill in the art would have found it obvious to have incorporated the motor of Nishikawa into the apparatus of Fritsch above as to likewise have operated the screw/pump elements as is required in the claims. Fritsch and Fritsch/Nishikawa do not appear to explicitly disclose one of the options in claim 18 for curing the material. However, like Fritsch and Nishikawa above, Gerada likewise uses a system that uses a screw or worm (24) (Gerada, par. 0067; Fig. 1) for depositing a material. Gerada additionally discloses the use of a second heating means (62) which can include an infrared radiator (which reads upon the claimed ‘radiation emitter’ or a heated substrate (Gerada, par. 0074-0076). Accordingly, in order to likewise assist in curing the material being deposited or extruded in Fritsch or Fritsch/Nishikawa above, one of ordinary skill in the art before the effective filing date of the claimed invention would have found it obvious to have specified that there is a radiation emitter or heated substrate/heater near the substrate as to have cured the material being deposited. *The limitation of “the nozzle positioned to deposit material exiting the nozzle onto an ever growing substrate that is a product of AM” is not considered limiting as it is an intended use. See MPEP 2114. Claim(s) 21 and 24 are rejected under 35 U.S.C. 103 as being unpatentable over Fritsch (US Patent No. 3,649,147) [optionally in view of Nishikawa (US 2015/0068667)] as applied to claim 1 above, and further in view of Marshall (US Patent No. 2,767,437). Regarding claims 21 and 24, Fritsch and Fritsch/Nishikawa discloses the subject matter of claim 1, but does not appear to explicitly disclose that the passage is coiled. However, Marshall discloses a similar extruder/pump to that of Fritsch/Nishikawa above and Marshall (Fig. 3) describes an extruder pump that has a coiled section (26) (Marshall, 6:40-6:61) that is used with a loop/coil in order to obtain a higher back pressure while at the same time decreasing the length of the passage and the space required for extruding/pumping the material out of the machine. One of ordinary skill in the art would have found it obvious to have incorporated such a coiled section into the apparatus of Fritsch or Fristch/Nishikawa above as to likewise have achieved the higher back pressure while decreasing the length of the passage as is required in the claim. Response to Arguments Applicant's arguments filed 3/16/2026 have been fully considered but they are not persuasive with respect to the updated rejections above. Please see below for a suggestion as to overcome the rejections, given that Examiner and Applicant’s representative discussed this feature during a recent interview, but no precise language was suggested or discussed, and the issue is still with respect to BRI and how the claim is interpreted. Upon consideration of the amendment to claim 1, it seems that the claim would need to recite further details as to how the motor is controlled, in order to completely overcome the previous rejection(s). The claim was amended to include that the motor is “electrically connected to a controller configured to control a rotation rate of the output shaft of the motor.” Both Fritsch and Nishikawa include language that would teach the idea that the motor is “electrically connected to a controller configured to control a rotation rate of the output shaft of the motor.” It seems that the idea that is required to be stated here in the claim is not only that the controller controls the rotation rate of the output shaft of the motor as is currently amended, but also that this control results in the conditions later recited in the claim (and argued to be missing from the claims, emphasis added). Examiner also points out that the claim currently reads “the passage configured to receive material . . . and expel heated material out of the passage at a flow rate proportional to a rotation rate of the output shaft of the motor and at a constant flow rate for a fixed rotation rate of the output shaft . . . “ which attributes “the passage” as having this function, and not “the controller” causing any of this to occur (emphasis added). Examiner also notes that the hopper is not in the claim, which (in the disclosure) is the element that feeds the material into the passage. Examiner again refers to MPEP 2114 where it states that functional claim language that is not limited to a specific structure covers all devices that are capable of performing the recited function. The elected claims are apparatus claims (directed to “a positive displacement pump”) which is not a computer-implemented functional device, and as such, the “configured to” limitations are not considered “structural” in nature, where they would be required by the prior art as in the case where it would narrow the functionality of the device by limiting the specific structure capable of performing the recited limitation. As such, these limitations would be considered to be an intended use and are not limiting to the claims. In the non-elected/withdrawn method claims, these limitations would be considered limiting, but these claims are not at issue. Furthermore, “for an additive manufacture application” is an intended use. See MPEP 2111.02(II) regarding preamble statements reciting purpose or intended use not being limiting where the body of the claim recites a structurally complete invention. However, it is noted that the compression and friction of the material against the sides of the passage would appear to necessarily or inherently cause some heating to the material in routine use between an upstream and downstream position within the passage. The rotation of the screw would also inherently cause some frictional heating of the material. Additionally, the heating elements (8) are clearly downstream from an inlet of the passage which would also mean that the passage would be capable of causing such heating. Applicant argues that this is not the case but has not provided evidence to the contrary. Furthermore, the limitations relating to “a flow rate proportional to a rotation rate of the output shaft of the motor” would also seem to be met as the rotation rate of the motor would directly cause the material to flow out of the opening, and would seemingly be related to how fast this motor is turning as this is the cause of material flow. This would not be required as with how the claim is drafted under BRI. Additionally, as discussed in MPEP 2115, the article worked upon by the claimed structure is not considered limiting to the claim. These issues would be rendered to be moot by being incorporated as computer-implemented functional limitations, which are effectively “structural” as outlined in recent case law. With respect to claim 18, the rejection has been updated as outlined above. With respect to claim 20, there is no example of a “static mixer” given in the specification, and so the BRI of this limitation can include any mixer that does not move relative to its own position. The gear pump remains in one location, and is therefore static as the material moves past it under BRI. There would be no comparable structure disclosed in the specification if adopting such a narrow definition as Applicant argues here and so this would not be considered reasonable. The term is not limited to items not contemplated by the disclosure. There is also no requirement that the same problem be addressed as in Applicant’s disclosure. In response to applicant's argument that “the problem of pressure driven backflow of material” is solved by the invention, the fact that the inventor has recognized another advantage which would flow naturally from following the suggestion of the prior art cannot be the basis for patentability when the differences would otherwise be obvious. See Ex parte Obiaya, 227 USPQ 58, 60 (Bd. Pat. App. & Inter. 1985). Accordingly, the rejections are maintained as updated above. Conclusion Any inquiry concerning this communication or earlier communications from the examiner should be directed to ANDREW D GRAHAM whose telephone number is (469)295-9232. The examiner can normally be reached Monday - Friday 7:30AM-4:00PM (CST). Examiner interviews are available via telephone, in-person, and video conferencing using a USPTO supplied web-based collaboration tool. To schedule an interview, applicant is encouraged to use the USPTO Automated Interview Request (AIR) at http://www.uspto.gov/interviewpractice. If attempts to reach the examiner by telephone are unsuccessful, the examiner’s supervisor, Christina Johnson can be reached at (571) 272-1176. The fax phone number for the organization where this application or proceeding is assigned is 571-273-8300. Information regarding the status of published or unpublished applications may be obtained from Patent Center. Unpublished application information in Patent Center is available to registered users. To file and manage patent submissions in Patent Center, visit: https://patentcenter.uspto.gov. Visit https://www.uspto.gov/patents/apply/patent-center for more information about Patent Center and https://www.uspto.gov/patents/docx for information about filing in DOCX format. For additional questions, contact the Electronic Business Center (EBC) at 866-217-9197 (toll-free). If you would like assistance from a USPTO Customer Service Representative, call 800-786-9199 (IN USA OR CANADA) or 571-272-1000. /ANDREW D GRAHAM/Primary Examiner, Art Unit 1742
Read full office action

Prosecution Timeline

Apr 06, 2023
Application Filed
Mar 17, 2025
Non-Final Rejection — §102, §103
Aug 20, 2025
Response Filed
Sep 14, 2025
Final Rejection — §102, §103
Nov 17, 2025
Response after Non-Final Action
Feb 17, 2026
Interview Requested
Feb 24, 2026
Applicant Interview (Telephonic)
Mar 02, 2026
Examiner Interview Summary
Mar 16, 2026
Request for Continued Examination
Mar 19, 2026
Response after Non-Final Action
Mar 21, 2026
Non-Final Rejection — §102, §103 (current)

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Prosecution Projections

3-4
Expected OA Rounds
60%
Grant Probability
82%
With Interview (+22.1%)
3y 8m
Median Time to Grant
High
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