Prosecution Insights
Last updated: April 19, 2026
Application No. 17/226,742

Fume Hood Having Structurally Integrated Components

Final Rejection §103
Filed
Apr 09, 2021
Examiner
HAMILTON, FRANCES F
Art Unit
3762
Tech Center
3700 — Mechanical Engineering & Manufacturing
Assignee
Imperial Systems Inc.
OA Round
5 (Final)
54%
Grant Probability
Moderate
6-7
OA Rounds
4y 0m
To Grant
92%
With Interview

Examiner Intelligence

Grants 54% of resolved cases
54%
Career Allow Rate
352 granted / 655 resolved
-16.3% vs TC avg
Strong +39% interview lift
Without
With
+38.8%
Interview Lift
resolved cases with interview
Typical timeline
4y 0m
Avg Prosecution
26 currently pending
Career history
681
Total Applications
across all art units

Statute-Specific Performance

§101
0.4%
-39.6% vs TC avg
§103
49.5%
+9.5% vs TC avg
§102
19.8%
-20.2% vs TC avg
§112
28.2%
-11.8% vs TC avg
Black line = Tech Center average estimate • Based on career data from 655 resolved cases

Office Action

§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 . Response to Arguments, Remarks Applicant is thanked for their October 29, 2025, response to the Office Action filed May 29, 2025. In response to the 35 U.S.C. §103 rejection of claims 1, 3, and 6 – 10 as being unpatentable over Leisner et al (US 2014/0213164), in view of Mennel (EP 1700644), in view of Worley (US 2,828,756), Applicant remarked (inter alia) that :”Leisner does not teach any leg component. Leisner's element 18 is a conduit which may be a suction conduit 32. There is no indication that's Leisner's conduit 18 has any of the structural elements of a "leg" in that there is no teaching or suggestion that the Leisner's hood 20 is supported at all by the conduit 18…A conduit in and of itself is not a leg and Leisner provides no teaching or suggestion of any other function than that of fluid flow. The examiner respectfully notes that claim 1 discloses “A fume hood comprising a curved canopy having a curved shape and supported by at least one hollow leg1”, but does not further disclose (e.g.:) that: the top end of the at least one hollow leg is connected to a hollow support member 16 to set the curved canopy 12 over the workspace 142; or the at least one hollow leg comprises a baseplate 46 connected to the bottom end of the hollow leg and is anchored to the ground with bolts3. It appears that the support features upon which applicant relies (i.e., structural elements between the leg and the hood and/or the hollow support member and/or the baseplate) - that would differentiate the instant application and the prior art - are not recited in the rejected claim(s). Although the claims are interpreted in light of the specification, limitations from the specification are not read into the claims. Please note the Leisner et al discloses: The “hood 20 is designed to be placed at or near (generally above) the metal-working operation 14” [0014], and The hood 20 comprises (fig 5) an outer shroud 38 connected to the conduit 18. With such a disclosure, it is reasonable that Leisner et al discloses wherein a canopy (38) is supported, directly or indirectly, by at least one hollow leg (18). PNG media_image1.png 399 712 media_image1.png Greyscale Lastly, during prosecution of the instant application, several pieces of prior art have been discussed that may be construed as disclosing a canopy supported by at least one hollow leg. Please refer to: Carlson (US 3,941,040), office action dated March 29, 2023, paragraphs 13 – 16; Zhang et al (CN 207615336), office action dated March 29, 2023, paragraph 41; Laufenberg (DE 3931142), office action dated March 29, 2023, paragraph 43; Leffel (US 1,085,742), office action dated November 27, 2023, paragraph 51; and Cox (US 4,606,260), office action dated April 29, 2025, paragraphs 23 – 27. In response to the 35 U.S.C. §103 rejection of claims 1, 3, and 6 – 10 as being unpatentable over Leisner et al (US 2014/0213164), in view of Mennel (EP 1700644), in view of Worley (US 2,828,756), Applicant remarked that (continued): “Examiner cites Worley for teaching the support of a curved shape by a hollow leg. This indicates that the Examiner recognizes that a structural component is necessary to support the curved canopy, but Worley does not teach that the hollow leg is in fluid connection with fume intake ports. While the Examiner separately agrees that a structural component and a fluid transfer component is necessary, the Examiner has not shown that there is any combination of the prior art that teaches both structural and fluid components as claimed in the instant application. The examiner respectfully notes that it was unnecessary for Worley to disclose that a hollow leg is in fluid communication with fume intake ports. Worley was provided to demonstrate that it was known in the art, before the effective filing date of the claimed in invention to provide a structure comprising: a curved canopy having a curved shape and supported by at least one hollow leg; said curved canopy having a plurality of gussets that are shaped to conform to the cross section of support said shape of said curved canopy, and said plurality of gussets comprising a plurality of openings. PNG media_image2.png 444 679 media_image2.png Greyscale As Applicant had amended the claims to further narrow the curved canopy, and gussets that support the canopy, Worley was provided to demonstrate that such a technique was known. In response to the 35 U.S.C. §103 rejection of claims 1, 3, and 6 – 10 as being unpatentable over Leisner et al (US 2014/0213164), in view of Mennel (EP 1700644), in view of Worley (US 2,828,756), Applicant remarked that (continued): Applicant remarked that, “the examiner cites Worley for teaching the support of a curved shape by a hollow leg. This indicates that the Examiner recognizes that a structural component is necessary to support the curved canopy, but Worley does not teach that the hollow leg is in fluid connection with fume intake ports. While the Examiner separately agrees that a structural component and a fluid transfer component is necessary, the Examiner has not shown that there is any combination of the prior art that teaches both structural and fluid components as claimed in the instant application. The examiner respectfully notes that Leisner et al was silent as to whether the canopy comprised “a plurality of gussets that support the shape of the curved canopy”, and so Worley was provided to demonstrate that it was known in the art before the effective filing date to provide a gusset that supports a curved shaped canopy. As Leisner disclosed a fume hood comprising a curved canopy supported by at least one hollow leg having an air intake port and an air outlet port, it was unnecessary to turn to Worley to provide such a teaching. In response to the 35 U.S.C. §103 rejection of claim 4 as being unpatentable over Leisner et al (US 2014/0213164), in view of Mennel (EP 1700644), in view of Worley (US 2,828,756), and further in view of Hammers (US 2013/0122795), Applicant remarked that “the dependent claims are allowable for at least the reasons stated above and for being dependent on allowable independent claims and such allowance is respectfully requested. The examiner respectfully notes that, as the rejection of claim 1 is maintained, and the teachings provided by Hammers are not in dispute, the rejection of dependent claim 4 has been maintained. In response to the 35 U.S.C. §103 rejection of claim 5 as being unpatentable over Leisner et al (US 2014/0213164), in view of Mennel (EP 1700644), in view of Worley (US 2,828,756), and further in view of Cox (US 4,606,260), Applicant remarked that “the dependent claims are allowable for at least the reasons stated above and for being dependent on allowable independent claims and such allowance is respectfully requested.” The examiner respectfully notes that, as the rejection of claim 1 is maintained, and the teachings provided by Cox are not in dispute, the rejection of dependent claim 4 has been maintained. Claim Interpretations In re Claim 1 and 3 – 10, the term “gusset”4 has been interpreted to be a “joist”5 or a “truss”6. 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 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 of this title, 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, and 6 – 10 are rejected under 35 U.S.C. §103 as being unpatentable over Leisner et al (US 2014/0213164), in view of Mennel (EP 1700644), in view of Worley (US 2,828,756). In re Claims 1 and 7, Leisner et al discloses a fume hood comprising: a curved canopy (fig 3: (38)) having a curved shape and supported by at least one hollow leg (18) wherein said curved canopy is set over a workstation (14); said curved canopy having an adjustable fume intake port (88) [0017] under its apex; and “The suction adjustment 36 … may also be located within the conduit 18. The suction adjustment 36 may include, for example, a butterfly valve, a damper, a louver, baffles, guide vanes, or another mechanical device which may be adjusted to limit the flow rate of air” [0017] wherein said at least one hollow leg (18) having a fluid connection (suction conduit (32)) with said fume intake port and having an air outlet port (at (16)) that is configured to be connected to a negative pressure system (22) such that fumes underneath said curved canopy are drawn into said fume intake ports, through said hollow leg, and out through said air outlet port to the negative pressure system [0017]. Leisner et al lacks wherein: the curved canopy has a plurality of intake ports, a plurality of gussets that support said shape of said curved canopy, said plurality of gussets comprising a plurality of openings to improve airflow under said curved canopy; and a welding screen suspended from the edges of said curved canopy. Mennel teaches a fume hood (figs 1 – 3) for a welding workstation, comprising: a curved canopy fig 1: (3)) having a curved shape and connected to at least one hollow duct (9) wherein said curved canopy is set over a workstation; said curved canopy having a plurality of adjustable (via throttles (17)) intake ports (4); at least one hollow duct (9) having a fluid connection with said fume intake ports (4) and having an air outlet port (at (6)) that is configured to be connected to a negative pressure system (central suction system: page 13/17, ln 22) such that fumes underneath said curved canopy are drawn into said fume intake ports, and out through said air outlet port to the negative pressure system; and a welding screen (fig 3: (16)) suspended from the edges of said curved canopy. It would have been obvious to a person having ordinary skill in the art before the effective filing date of the claimed invention to modify the system of Leisner et al, as taught by Mennel, such that: the curved canopy has a plurality of intake ports, and a welding screen suspended from the edges of said curved canopy for the benefit of the plurality of intake openings providing “draft” across the hood, and to improve a central suction effect by utilizing welding screens, making the hood operator’s utilization more effective. Worley teaches a structure (figs 1, 3: (10)) comprising: a curved canopy (fig 1: (14/36)) having a curved shape and supported by at least one hollow leg (20/30) (“vertically extending pipes”: col 2, lns 25 – 27) wherein said curved canopy is set over an occupied space (col 1, ln 17); a plurality of gussets (16) that support said shape of said curved canopy (col 2, lns 51 – 58), said plurality of gussets (16) comprising a plurality of openings (apparent, as openings are formed between rod braces (25) of the gusset (16)) to improve airflow under said curved canopy; and a roof panel which may be opened or closed, without affecting the stability of the structure (col 1, lns 36 – 39), to afford flexibility in lighting, and ventilation (col 2, lns 70 – 72). It would have been obvious to a person having ordinary skill in the art before the effective filing date of the claimed invention to modify the proposed system as taught by Worley, such that the hood is supported by a plurality of curved gussets, as choosing from a finite number of identified, predictable solutions is within the capabilities of a person having ordinary skill in the structural arts, and they would have a reasonable expectation of success, based upon the characteristics of the science or technology, its state of advance, the nature of the known choices, the specificity or generality of the prior art, and the predictability of results in the area of interest. In re Claim 3, the proposed system has been discussed, wherein Leisner et al discloses further comprising said curved canopy (38) is shaped to trap and direct fumes towards said fume intake ports [0018, 0021]. In re Claims 6 and 8, the proposed system has been discussed (see above, In re Claim 1), wherein Worley teaches the system comprises an opening in said curved canopy to allow for ventilation. Regarding the limitations that the opening is: “to allow an overhead crane to position objects under said curved canopy”, and “to allow a crane to position large, suspended objects within said workstation”; It has been held that a recitation with respect to the manner in which a claimed apparatus is intended to be employed does not differentiate the claimed apparatus from a prior art apparatus satisfying the claimed structural limitations. In re Claim 9, Leisner et al discloses further comprising wherein the negative pressure system is one of a stand-alone extraction unit (fig. 1) and a central unit (fig 2) [0020] that may extract fumes from a plurality of fume hoods. In re Claim 10, Leisner et al discloses further comprising said workstation is one of a welding station (fig 1: (52)) [0019] and robotic welding station. Claims 4 is rejected under 35 U.S.C. §103 as being unpatentable over Leisner et al (US 2014/0213164), in view of Mennel (EP 1700644), in view of Worley (US 2,828,756), and further in view of Hammers (US 2013/0122795). In re Claim 4, Leisner et al discloses further comprising a spark trap (48) [0018] mounted within said hollow support leg, but is silent as to whether it is detachably mounted. Hammers teaches a fume extraction canopy (fig 1: (10)) set over a welding workstation (12), comprising: a plurality of fume intake ports (fig 5, annotated below) and an air outlet port (18) that is configured to be connected to a negative pressure system [0019] a spark trap (fig 5: 54/42/56/44/40) [0022, 0025] that is detachably mounted (portion (40) is detachably mounted [0023]) PNG media_image3.png 417 761 media_image3.png Greyscale It would have been obvious to a person having ordinary skill in the art before the effective filing date of the claimed invention to modify proposed system as taught by Hammers, such that the spark trap is detachably mounted, for the benefit of facilitating system operation and maintenance. Claims 5 is rejected under 35 U.S.C. §103 as being unpatentable over Leisner et al (US 2014/0213164), in view of Mennel (EP 1700644), in view of Worley (US 2,828,756), and further in view of Cox (US 4,606,260). In re Claim 5, the proposed has been discussed, wherein Leisner et al discloses further comprising a spark trap (48) that comprises a series of baffles (fig 5: (48)) mounted within said hollow support leg. However, Leisner et al lacks wherein the spark trap is comprised of opposingly oriented baffles. Cox teaches a movable welding station (Abstract), comprising: a canopy (11) supported by at least one hollow leg (fig 1: (12, 13)); a fume intake port (30) and having an air outlet port (49) that is configured to be connected to a negative pressure system (fan (50)); and a spark trap, wherein the spark trap is comprised a series of opposingly oriented baffles (fig 2: (31, 35, 36); col 3, ln 57 – col 4, ln 5). PNG media_image4.png 297 130 media_image4.png Greyscale It would have been obvious to a person having ordinary skill in the art before the effective filing date of the claimed invention to modify the proposed system, as taught by Cox, such that the spark trap is comprised of opposingly oriented baffles, for the benefit of providing a serpentine flow path, further preventing a spark from traveling into the system. 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. The prior art made of record and not relied upon is considered pertinent to applicant's disclosure can be found in the PTO-892: Notice of References Cited. Contact Information Any inquiry concerning this communication or earlier communications from the examiner should be directed to (she/her) Frances F. Hamilton whose telephone number is 571.270.5726. The examiner can normally be reached on Tu-Th; 9 – 6. 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, Michael Hoang can be reached on 571.272.6460. 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, please visit: https://patentcenter.uspto.gov. For more information about Patent Center, please visit https://www.uspto.gov/patents/apply/patent-center and for information about filing in DOCX format please visit https://www.uspto.gov/patents/docx. 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, please call 800.786.9199 (in USA or Canada) or 571.272.1000. /Frances F Hamilton/ Examiner, Art Unit 3762 /MICHAEL G HOANG/Supervisory Patent Examiner, Art Unit 3762 1 Leg (n): “a branch or part of an object or system”. Merriam-Webster, Incorporated © 2026 2 Specification paragraph [0025, 0027] 3 Specification paragraph [0030] 4 Gusset (n): a plate or bracket for strengthening an angle in framework (as in a building or bridge). Merriam-Webster incorporated 5 Joist (n): any of the small timbers or metal beams ranged parallel from wall to wall in a structure to support a floor or a ceiling. Merriam-Webster incorporated 6 Truss (n): an assemblage of members (such as beams) forming a rigid framework. Merriam-Webster incorporated
Read full office action

Prosecution Timeline

Apr 09, 2021
Application Filed
Mar 23, 2023
Non-Final Rejection — §103
Aug 18, 2023
Response Filed
Nov 15, 2023
Final Rejection — §103
May 17, 2024
Request for Continued Examination
May 20, 2024
Response after Non-Final Action
Jul 03, 2024
Non-Final Rejection — §103
Jan 10, 2025
Response Filed
Apr 19, 2025
Non-Final Rejection — §103
Oct 29, 2025
Response Filed
Feb 10, 2026
Final Rejection — §103 (current)

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Study what changed to get past this examiner. Based on 5 most recent grants.

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Prosecution Projections

6-7
Expected OA Rounds
54%
Grant Probability
92%
With Interview (+38.8%)
4y 0m
Median Time to Grant
High
PTA Risk
Based on 655 resolved cases by this examiner. Grant probability derived from career allow rate.

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