US 2744497

I'll search for this specific patent number and related litigation docket information.

Let me check for litigation/docket information and confirm the USPTO record.

Search notes and scope

I ran targeted searches for the literal identifier 2744497 against patent databases and open-web docket content. Two caveats up front:

1. I do not have direct API access to USPTO PatentCenter or to the CAFC's docket system. My results come from general web/patent-search sources. Treat the litigation finding below as "nothing located," not as a certified negative.
2. Most hits for the bare string "2744497" are different identifiers, not this patent. I did not merge them: EP2744497B1 (Helsinn, netupitant/palonosetron), FR2744497A1 (hydraulic distribution), AU2744497A (displacement-current sensor), JP2744497A (recording/reproducing apparatus), and a Florida FEI number 87‑2744497 are all unrelated. The authoritative record for US 2,744,497 A is the Google Patents full text supplied in your prompt, which I treat as controlling over search noise.

Litigation / CAFC 2026: I found no CAFC 2026 docket entry, district-court action, or IPR/PGR involving US 2,744,497. This is expected — the patent's term ran out long ago (anticipated expiration 1973‑05‑08, legal status "Expired – Lifetime"), and Google Patents lists no assignment or reexamination history. I cannot rule out a 2026 filing by name search alone, so I flag this as uncertain rather than confirmed absent.

(Minor housekeeping: your message dates this April 26, 2026, while my operating date is 2026‑09‑28. Nothing in the summary below turns on that gap.)

US 2,744,497 A — bibliographic summary

Source: https://patents.google.com/patent/US2744497/en

On the abstract: patents of this vintage were not required to carry a formal abstract, and none is printed on US 2,744,497. What Google Patents renders as the "Definitions" summary is drawn from the specification's opening paragraph, which reads: the invention "relates to an improved self-feeding feeder especially, but not exclusively, for weaning pigs," with the stated objects of simpler construction, easier sanitation, adjustable gravity feed rate, and minimum feed waste. I am not inventing an abstract that does not exist in the document.

Plain-language overview of the claims

The device is a wooden gravity-flow trough: feed is dumped into a hopper space at the rear, slides down a forward-sloping floor, and puddles behind a low retaining lip at the front, where pigs eat out of individual stalls. The rate of flow is set by how high a sliding gate hangs above that sloping floor. All three claims are drafted as separate, self-contained claims (claims 2 and 3 restate claim 1's structure rather than incorporating it by reference).

Claim 1 — the base structure. An animal feeder with: two end walls; a vertical back wall spanning and fastened between them; a bottom plate spanning between the end walls and sloping forward (downward) from the back wall; a top wall above it with a rear edge set forward of the back wall (leaving a gap for the feed gate); vertical cleats on the end walls whose forward edges sit behind that top-wall rear edge; a vertical feed-regulating plate that slides between the top wall's rear edge and the cleats' forward edges, with its end edges sliding against the end walls; and mounting means between an end wall and the plate's end edge that holds the plate with its lower edge over and spaced above the bottom wall. The spacing is what meters the flow.

Claim 2 — the metering mechanism, spelled out. Same structure as claim 1, but it specifies what the "mounting means" is: vertically spaced sockets (holes) in the end edge of the regulating plate, plus removable pins passing through the end wall and seated in a selected socket. Pull the nail, slide the gate, reinsert — the lower edge sits higher or lower above the floor, changing the feed rate. This is the adjustability feature the specification calls out as allowing the plate's lower edge "26'" to be set "at different heights … for regulating flow of feed down along the bottom wall."

Claim 3 — base structure plus feeding stalls. Everything in claim 1, plus spaced partitions secured to and depending from the top wall, forwardly of the regulating plate, the partitions having rear edges that the regulating plate slidably engages below the top wall. The partitions divide the front trough into separate feeding stalls (which is why the specification notes the device may be built with "any desired number of partition walls 22, at desired spacings"). In the drawing the partition lower ends are beveled (23, 24) to seat against the retaining plate 16 and the sloping bottom wall 13.

Claim-drafting observation (analysis, not ground truth): claim 3's added subject matter is narrow — it largely re-describes a feeder that claim 1 already covers structurally, since a competitor could avoid claim 3 by omitting the partitions while still reading on claim 1. Claim 2 similarly depends for its distinct scope on the specific pin-and-socket limitation; a differently implemented height adjustment would fall outside claim 2 but remain within claim 1's broader "mounting means" language. The specification's key structural elements that the claims do not recite are the feed retaining plate 16 at the forward edge of the bottom wall and the abbreviated back wall 8 that stops about halfway down — these are described features of the preferred embodiment, not claim limitations.

OCR/typo cautions in the source text: the Google Patents OCR renders the regulating plate's lower edge both as "26'" and "26," and includes artifacts such as "bottorii wall," "diiferent," "rear edg 20," and an interleaved "Patented May 8, 6" page-break fragment inside claim 2. None of these change the substance above.

I'll search for litigation involving US patent 2744497 across litigation-tracking sources.

Initial results are mostly false positives (a modern "449 Patent" in an IPR, and unrelated corporate filings). Let me search litigation-specific databases directly.

Bottom line

I found no litigation — none — involving US Patent 2,744,497. No case in any federal district court, the Court of Appeals for the Federal Circuit, the ITC, or before the PTAB is recorded against this patent in the sources searched. All hits for the string "2744497" in the searches were false positives, which I detail below so the record is clear.

What patent we are dealing with

US 2,744,497, "Self-feeding pig feeder," inventors Milton E. Fisher and Paul C. Fisher (Cedar Falls, Iowa), assignee: Individual (unassigned to any company). Application 373,026, filed 1953-08-07, granted 1956-05-08, 3 claims (Class 119/53.3). Google Patents records legal status: "Expired – Lifetime," with "Anticipated expiration" dated 1973-05-08. (The statutory 17-year term from the 1956 grant ran to May 8, 1973.)

Searches performed and why the results were negative

The false positives, identified

1. EP 2744497 — "Therapeutic combinations of netupitant and palonosetron," Helsinn Healthcare SA. This is a European application/publication number, not US 2,744,497. It appears in the Montenegro IP Gazette, the Czech Industrial Property Bulletin, and the Greek OBI gazette. Not related.
2. AU 2744497 A (published 1997-11-19) — an Australian application number, cited in WO 2003/101785. Not related.
3. Underlying PTAB IPR material — the "'449 Patent" discussed in that petition concerns "repository of last resort" data-replication claims and a 2000 priority date. This is a different US patent whose number merely ends in 449. I have not confirmed its full number here, and I will not guess it.
4. FEI Number 87-2744497 — a Florida nonprofit corporate filing (Rolling Out Inc.). A tax ID, not a patent.
5. Brazilian and Chinese administrative numbering (e.g., "E.P. DE OLIVEIRA ME" at 2744497; a Ningling county roster entry 2744397) — coincidental numeric matches.

Important caveats about the negative finding

• Databases I relied on are modern. CourtListener/RECAP, Unified Patents' litigation portal, Justia, Docket Navigator-style compilations, and PACER's electronic dockets generally do not reach back to the 1956–1973 window in which this patent was enforceable. A suit filed in, say, 1958 in the Northern District of Iowa would likely not appear in any of these systems.
• Pre-1973 patent disputes were also frequently unreported or settled, and many older decisions exist only in print reporters (F. Supp., F.2d, USPQ) rather than in any searchable litigation database.
• A lawyer's diligence check remains the reliable path for a patent of this vintage: check the Federal Reporter/Federal Supplement digests and the Decisions of the Commissioner of Patents for the 1956–1973 period, and the assignment records (USPTO Assignment Search) to see whether the patent was ever assigned to a company with enforcement capacity. Notably, Google Patents lists the assignee as "Individual," and the patent's own citation list (7 prior-art references, 4 later citations) reflects no litigation-driven citation activity.

Answer to your direct question

As of April 26, 2026, based on the sources searched, there is no known litigation involving US Patent 2,744,497. I cannot rule out an unrecorded or pre-electronic-docket infringement action from the patent's 1956–1973 term; if one exists, it would need to be located in print-era reporters, not in the litigation portals that were searched.

If you want, I can run targeted follow-up queries (e.g., against Justia's historic federal opinions, the Federal Reporter archive, and USPTO assignment records) to try to close that pre-1973 gap — but I would not want to represent the current negative finding as complete for that era.

I'll verify the structured block against web sources before writing up.

Proceedings overview

Zero AIA trial proceedings are on file against US 2,744,497 — no IPRs, no PGRs, no CBMs, no derivation proceedings — which means there is no PTAB record to litigate against and, more to the point, no live patent to defend against: the patent issued 1956-05-08, expired 1973-05-08, and any infringement theory built on it is not merely weak but jurisdictionally and temporally foreclosed.

I want to be explicit about the basis for the count before the reader relies on it:

Methodological caveat, stated plainly: I do not have authenticated programmatic access to PTAB E2E, the PTAB API, or the CAFC docket in this session. My count is the ODP structured block plus negative search results. That is a "nothing located" finding, not a certified absence. To independently confirm, the authoritative sources are the PTAB API/E2E trial search at https://ptab.uspto.gov/ and the PTAB Decisions page, plus the PTAB Open Data API at https://developer.uspto.gov/ptab-api/swagger-ui.html — search by patent number 2,744,497 (and by application 373,026).

The two prior sections of this analysis already flagged the same thing twice: the litigation/summary section found no CAFC 2026 docket entry and no district-court action, and the PTAB-specific block states the default is "no PTAB activity on file." There is no contradiction between the sections — all three converge on zero. My result confirms theirs rather than revising them.

Categorical bar to AIA trial vehicles on this patent

There is no proceeding to walk through, so the useful analysis is why the field is empty. This matters because "no IPRs were filed" can mean either "nobody bothered" or "nobody could." Here it is overwhelmingly the latter, and the reason is structural, not tactical:

1. PGR is legally unavailable. Post-grant review under 35 U.S.C. §§ 321–329 applies only to patents subject to first-inventor-to-file, i.e., applications with an effective filing date on or after 2013-03-16. This application was filed 1953-08-07. PGR jurisdiction never existed for this patent.

2. CBM is unavailable twice over. The transitional Covered Business Method program under AIA § 18 (Pub. L. 112-29) required the patent to claim "a method or corresponding apparatus for performing data processing or other operations used in the practice, administration, or management of a financial product or service." A gravity-fed pig trough is not a covered business method. Independently, the CBM program sunset for new petitions on 2020-09-16, and the patent had already been expired for 47 years at that point.

3. IPR is not categorically barred, but is hollow. I want to correct a common overstatement: IPRs can be filed against expired patents, and the Board has instituted on them — though with material consequences, because the patent owner cannot amend claims and claim construction proceeds under Phillips rather than the broadest-reasonable-interpretation standard. So the correct statement is not "an IPR was impossible." It is that an IPR would have been pointless: there is no infringement exposure to estop, no defendant with standing-driven incentive, and no commercial reason for a petitioner to spend a filing fee plus 12 months of trial on a patent whose last enforceable day was in 1973.

4. Enforcement is time-barred, which is what actually protects a defendant. The 17-year term from issue ran 1956-05-08 → 1973-05-08. Under 35 U.S.C. § 286, a patentee may recover damages only for infringement committed within six years before suit — which for this patent closes in 1979. Any demand letter today citing US 2,744,497 is asserting an unenforceable right, and the correct response is not an IPR petition but a § 286 / laches / patent-expiry letter, or a declaratory-judgment action if a paper trail is genuinely needed.

Terminal-date cross-check: The ODP record's "Anticipated expiration 1973-05-08" is exactly issue date + 17 years, which is the pre-URAA term under the law in force when this patent issued. That is internally consistent and confirms the patent has been dead for over five decades. Claim status is therefore not "canceled by PTAB" or "sustained by PTAB" — it is "expired, never adjudicated, no AIA challenge ever filed."

Strategic summary

Claim status: all three claims expired untested. Claims 1, 2 and 3 of US 2,744,497 were never the subject of an AIA trial, a reexamination, a reissue, or (per the record) any litigated validity determination. There is accordingly no CANCELED / SUSTAINED / INSTITUTED ledger to report — a posture that is unusual in this workflow template only because the patent predates the entire post-grant regime by 56 years. Anyone who needs to know what claims 1–3 cover for a freedom-to-operate or prior-art analysis has to do a primary-source claim-reading against the specification (the prior generated section already mapped that out: claim 1 = base trough structure with sliding metering gate; claim 2 = claim 1 plus pin-and-socket height adjustment; claim 3 = claim 1 plus feed-stall partitions). Note that validity today would be assessed under pre-AIA §§ 102/103 with a 1953 critical date, and the seven examiner-cited references on the face of the patent (US 878,086; 985,047; 1,137,460; 1,221,355; 1,227,892; 1,498,697; 1,750,580) are the starting prior-art set — but this is an academic exercise for an expired patent, not a defensive playbook.

Estoppel landscape: none exists, and none can arise. Section 315(e)(2) estoppel attaches to a petitioner, real party in interest, or privy that obtains a final written decision. There is no petitioner and no FWD, so no party is estopped from anything. Conversely — and this is the practical asymmetry a defendant should internalize — there is also no PTAB record to inherit as a shield. Contrast the typical assertion scenario, where an earlier defendant's IPR win hands later defendants an estoppel-bound, already-adjudicated invalidity roadmap. Here there is no roadmap, because the terrain no longer exists. If someone today is asserting this patent, the estoppel question is moot and the request for a § 315(e)(2) analysis should be redirected to whether the assertion itself is sanctionable.

Pattern signals: not applicable, and their absence is diagnostic. There is no repeat petitioner (there are no petitioners), no evidence of an aggressive PTAB appeal practice by the patent owner, and no defensive aggregator such as Unified Patents anywhere in the chain — Unified and its peers target live, asserted patents in software and networking, not 1956 agricultural hardware. The absence of PTAB activity here is not the standard "well-asserted patents eventually attract IPRs" signal in reverse. It is the much stronger signal that this patent has never been asserted in the AIA era at all. For comparison, a patent that actually gets asserted — even a weak one — typically draws an IPR within 12 months of the first complaint, because § 315(b) gives an accused infringer a one-year window from service. No § 315(b) clock ever started for this patent.

Recommended next steps

If no assertion is pending (the expected case): There is nothing to do on the PTAB side, and I would advise against commissioning an IPR-style invalidity analysis as a defensive expenditure. The patent expired 1973-05-08 and enforcement is time-barred under 35 U.S.C. § 286 as of 1979. Record that in the file and move on.

If someone is citing US 2,744,497 in a demand letter today — and I found no evidence that anyone is, so this is a contingency, not a report: do not file an IPR. Filing an IPR against an expired patent is possible but would be a strategic error here, because it tacitly treats the patent as live and because no petitioner could be rewarded with the estoppel benefit that normally justifies the cost. Instead:

1. Verify the record yourself, independently. Run the patent number against PTAB E2E (https://ptab.uspto.gov/) and the CAFC docket, and pull the Google Patents record at https://patents.google.com/patent/US2744497/en for the "Expired – Lifetime" status and the 1973-05-08 anticipated expiration. Do not rely solely on my negative search result or on the ODP block, both of which carry the caveats I stated up front.
2. Check for a family or continuation you were not told about. This is the one genuinely useful follow-up. The record shows a single US application (Serial 373,026) with no continuation, no CIP, no divisional and no foreign family members. If the assertion points at a different patent, that patent — not this one — is the analysis target, and my zero-proceeding finding does not transfer to it.
3. If a sanctionable assertion actually appears, the response is a § 286 / patent-expiry letter, with an eye toward Rule 11 or § 285 exposure for the asserting party. Preserve the demand letter.

If you are looking for a trial-stage milestone calendar: there is none to build. No institution decision deadline, no oral hearing date, no one-year FWD due date under 35 U.S.C. § 316(a)(11) exists or could exist for this patent. Any such calendar you might be handed is fabricated.

Bottom line for a defendant: the patent is a 1956 wooden pig feeder that has been expired since 1973 and has never been the subject of an AIA trial — zero proceedings, zero estoppel, zero surviving-claim analysis available. If a demand letter cites US 2,744,497, the problem is with the demand letter, not with your product.

I'll search for assignment/reel-frame records and any ownership history for this patent.

Inventors

Both names appear on the face of the printed patent ("Milton E. Fisher and Paul C. Fisher, Cedar Falls, Iowa, Application August 7, 1953, Serial No. 373,026") and in the drawing's signature block ("Milton E. Fisher, Paul C. Fisher"). Source: https://patents.google.com/patent/[US2744497](/patent/US2744497)/en

Unusual-pattern review:

• Shared surname, same city, joint filing. The two inventors are almost certainly related (brothers or father/son). For a 1953 farm-equipment filing this is the ordinary pattern for a shop-built or family-run operation, not a red flag. I make no finding beyond the shared residence, which is what the record actually shows.
• No "all inventors departed the assignee" signal can exist here. There is no corporate assignee on the record (see below), so the classic pre-fire-sale tell ("inventors left the original assignee within 12 months") is structurally inapplicable. All I can say is that neither inventor appears as an assignor in any record I located.
• Identity caution — do not conflate. A well-documented inventor Paul C. Fisher (1913–2006) founded the Fisher Pen Company / Fisher Space Pen Co. and obtained US 3,285,228 (the AG7 "Anti-Gravity Pen"). Public biographies of that man place him at a Cedar Rapids, Iowa bakery (1936–38), at Kansas State University, at Aetna Ball Bearing, and later in Boulder City, Nevada. Sources: Nevada Assembly Concurrent Resolution No. 74 (1999), https://www.nvleg.gov/Session/70th1999/bills/ACR/ACR74.pdf; https://spacepen.ca/paul-c-fisher/. I therefore cannot identify the Cedar Falls Paul C. Fisher of this patent as the pen inventor, and I do not assert it. Note the records say Cedar Falls, not Cedar Rapids — I am not auto-correcting either one.

Original assignee

None — the patent issued to the two inventors as individuals.

Google Patents records the assignee fields as "Original Assignee: Individual" and "Current Assignee: Individual," which in Google's schema is a null placeholder, not a company name. There is no corporate assignee to profile. Consequently:

• Product embodying the claims: No manufacturer or brand is identified anywhere in the document, and the specification speaks only of how the device may be built — "preferably made of wood in readily obtainable board sizes, for the sake of convenience and economy," and "can also be made in any wanted sizes and with any desired number of partition walls 22." That is a builder's description, not a product catalogue listing. There is no evidence of a commercial product, catalogue number, or trade name of record. This is an absence of evidence, not evidence of absence — a 1953 Iowa farm-shop feeder could easily have been sold regionally without leaving a traceable record.
• Primary line of business: Not determinable.
• Current status (operating / acquired / dissolved / bankruptcy): Inapplicable — no entity. Neither inventor is identifiable in any corporate register I could reach via the searches I ran.
• Legal status of the patent: Expired – Lifetime; anticipated expiration 1973-05-08 (20 years was not the rule; this term ran 17 years from issuance on May 8, 1956). No reissue, reexamination, disclaimer, or maintenance-fee event appears in the legal-events record.

Contradiction check against the prior section: none. The earlier bibliographic summary already flagged "no assignment recorded on the face of the record," and nothing I found in this pass changes that.

Assignment timeline

The USPTO Assignment Center has no records for this patent, and I found no recorded assignment anywhere else. Per your protocol I state that plainly and stop here.

Basis for that call, so you can weigh it:

1. Google Patents legal events for US 2,744,497 contain exactly three entries — 1953-08-07 application filed / priority to US373026A; 1956-05-08 application granted and publication of US2744497A; 1973-05-08 anticipated expiration. There is no Assignment, Security Agreement, Merger, Change of Name, License, Release, or Correction event in the chain.
2. Targeted searches for a reel/frame record ("US2744497 assignment reel frame," "2,744,497 assignment Milton Fisher Paul Fisher," "2744497 assignment reel frame record") returned zero relevant hits.
3. The only "2744497" hits in circulation are other identifiers, which I did not merge into this record: EP2744497B1 (Helsinn, netupitant/palonosetron), FR2744497A1 (hydraulic distribution), AU2744497A, JP2744497A, and a Florida FEI number 87-2744497.

Caveats I cannot discharge:

• I do not have a live session against https://assignmentcenter.uspto.gov/ or the legacy https://assignment.uspto.gov/patent/index.html index, so this is "nothing located," not a certified negative. Verify directly by patent number at those URLs.
• Recording of assignments was not compulsory, and pre-1955 USPTO assignment records are acknowledged to be incomplete. An unrecorded or later-recorded transfer of this patent (including a late recording filed decades after expiration, which does happen) would not surface in any source I reached. The absence of a record means the last owner of record remains the inventors, not that no transfer ever occurred.
• The patent has been expired since 1973-05-08, so no enforcement-driven chain (pre-litigation transfer, cascading LLCs, securitization) is legally useful for this number. I found no CAFC, district-court, ITC, or IPR/PGR proceeding naming it.

Verification links: https://assignmentcenter.uspto.gov/ · https://assignment.uspto.gov/patent/index.html · https://patents.google.com/patent/US2744497/en

Per your instruction, I am stopping after the assignment-timeline section because the record contains no assignments. The timeline diagram, the eight NPE/troll-pattern signals, and the reasoned verdict are therefore not rendered; for bookkeeping, the verdict category this record falls into is exactly the one you defined for this situation — Insufficient data (no records, or only the original assignment) — with the added note that here there is not even an original assignment, only an issuance to individual inventors.

I'll search the USPTO-facing record and the cited references to ground this analysis.

Let me pull the individual prior-art references directly.

Scope note and search result

I could not retrieve the substantive text of the seven cited references through open-web search — the queries returned unrelated documents (e.g., US5595139, US4582023, US1154073, US9420759), not the pre-1930 patents at issue. So the per-reference descriptions below are reasoned correlations from the citation metadata (number, title, inventor, filing/publication dates, and the fact that all seven were examiner-cited), not verified readings of full texts. I flag this explicitly rather than presenting inference as established fact. The one authoritative source remains the Google Patents full text supplied in the prompt: https://patents.google.com/patent/[US2744497](/patent/US2744497)/en

Also, per the operating rule, the bare number 2744497 resolves only to US 2,744,497 A, "Self-feeding pig feeder." Search noise for EP2744497B1, FR2744497A1, AU2744497A, JP2744497A, and Florida FEI 87-2744497 was excluded and not merged, consistent with the earlier section.

Critical distinction first: "citations" vs. "cited by"

Before the § 102 analysis, the direction of citation matters legally:

The "Similar Documents" list (e.g., US2698004A "Piglet feeding device," US2834320A "Pig feeder," US2749881A "Feeder for little pigs," US2959154A "Swine feeder," US3180319A "Hog trough") is algorithmically generated by subject-matter similarity, not examiner citation, and those items post-date the 1953 filing. Do not treat them as § 102 art. One exception worth flagging: US1737797A, "Sanitary feed trough," published 1929-12-03 appears in the Similar Documents list and does predate the filing — but it is not an examiner citation and I have not verified its disclosure.

The seven examiner-cited references

All fall in the same field (gravity hoppers/troughs; class A01K 5/00–5/02), consistent with the 2,744,497 classification.

Discrepancy flagged (no auto-correction): for US 1,221,355, the printed patent's reference list names the inventor as "Moe," while Google's structured citation record attributes the document to "Otis & Moe Mfg Company" (apparently the assignee). Both renderings are preserved above; this is a naming/attribution difference, not a different document.

Note the date ordering: Google's citation table gives filing/priority dates, and the printed patent lists only publication dates (Feb. 4, 1908 / Feb. 21, 1911 / Apr. 27, 1915 / Apr. 3, 1917 / May 29, 1917 / June 24, 1924 / Mar. 11, 1930). The two sets are consistent.

§ 102 element mapping

Recall the element breakdown established in the prior section. Denote the claim-1 elements:

• (a) pair of end walls
• (b) vertical back wall between/secured to the end walls
• (c) bottom plate between the end walls, declining forwardly from the back wall
• (d) top wall above the bottom wall with its rear edge spaced forwardly of the back wall
• (e) vertical cleats on the end walls, forward edges rearward of the top wall's rear edge
• (f) vertical feed-regulating plate slidably captured between the top-wall rear edge and the cleat forward edges, end edges sliding on the end walls
• (g) mounting means between an end wall and the plate's end edge holding the plate's lower edge over and spaced above the bottom wall

Claim 2 = (a)–(g) + vertically spaced sockets in the plate's end edge + removable pins through the end wall into a selected socket.
Claim 3 = (a)–(g) + spaced partitions secured to and depending from the top wall forwardly of the regulating plate, the plate slidably engaging their rear edges below the top wall.

Per-reference assessment

7. US 1,750,580 (Ebel, 1930) — likely the closest reference. A "chicken-feeding hopper" of 1930 is, in this art, typically a gravity hopper discharging onto a trough floor through a bottom gap whose size is set by an adjustable gate. That maps onto elements (c)/(d)/(f)/(g) — a sloping or floor-fed discharge with an adjustable-height gate — and is the most probable § 102 candidate against claim 1. Its relevance to claim 2 turns on whether Ebel's adjustment uses pin-and-socket (rather than a thumbscrew, sliding hoop, or notched gate), which I have not verified; on the face of the title/date, I cannot assert it. Relevance to claim 3 (partitions depending from the top wall) is unverified.

6. US 1,498,697 (Scholle, 1924) — hopper + trough with feed regulation. The title squarely places it in the gravity-hopper-and-trough combination. Strong candidate for the general combination in claim 1; a possible secondary § 102/§ 103 reference for a height-adjustable discharge gate. Again, the pin/socket specifics of claim 2 and the top-wall-mounted partitions of claim 3 are unverified.

5. US 1,227,892 (Darby, 1917) — "Counter-bin." A bin with a movable/sliding element (measurement or partition function). Probable teaching of a slidable vertical plate within a bin — relevant to element (f) and, if the slide is fixed at discrete heights, to claim 2's adjustability concept. Whether it discloses the rearward-spaced top wall (d) and cleat guides (e) is unverified.

4. US 1,221,355 (Moe / Otis & Moe, 1917) — "Feed-hopper." Gravity hopper feeding a trough; likely discloses the hopper reservoir and a discharge-to-trough arrangement, touching (b)/(c)/(d). Candidate § 102 art for the broad combination in claim 1, but the specific cleat-and-regulating-plate capture (e)/(f) is unverified.

3. US 1,137,460 (Carlson, 1915) — "Hog-feeding trough." Same species as the patent (hog feeding trough). Likely discloses end walls and a trough floor (a)/(c) and possibly partitions or stalls — most relevant to claim 3's partition feature, if present. Unlikely to anticipate claim 1's top-wall/regulating-plate subcombination.

2. US 985,047 (McGinnis, 1911) — "Combined feed-trough and rack." Trough plus rack structure; probable end walls and trough (a)/(c), and possibly dividers — potential § 102 relevance to claim 3 only if it shows partitions. Not a plausible anticipant of claim 1 in full.

1. US 878,086 (Pearson, 1908) — "Feed-trough," the oldest reference. A bare feed trough is the most remote. On metadata alone it can plausibly disclose only the trough/end-wall environment (a)/(c). Least likely to anticipate any of claims 1–3 standing alone; best characterized as background art showing the feed-trough field.

Bottom line on anticipation

• No single reference appears, on the available metadata, to disclose all elements (a)–(g) of claim 1, let alone the added limitations of claims 2 or 3. The examiner's citations are more naturally read as § 103 obviousness-type references assembled against the combination, with each reference supplying a subset of elements.
• Claim 2 is the strongest claim on this record: the pin-and-socket height adjustment through the end wall is a specific mechanism none of the seven titles suggests was old in this exact form.
• Claim 3's partitions depending from the top wall with rear edges slidably engaged by the regulating plate is likewise a specific arrangement distinct from the generic trough dividers one would expect in McGinnis/Carlson.
• Because 2,744,497 expired 1973-05-08 ("Expired – Lifetime"), any § 102 analysis here is of historical and defensive-validity interest only; there is no live invalidity posture.

What I could not do, and the proper next step

My open-web searches for the seven numbers returned zero substantive matches — they surfaced unrelated patents and periodicals. I therefore cannot certify the disclosure content of any of the seven references, and the anticipation mappings above are explicitly provisional.

To convert this into a defensible § 102 analysis, retrieve the full text/PDF of each number from USPTO Patent Public Search or Google Patents (URL pattern https://patents.google.com/patent/US878086A/en, substituting each number), and read each for elements (a)–(g). The one point I will state with high confidence from the authoritative record is the citation set itself: seven examiner-cited U.S. patents (1908–1930), all pre-dating the Aug. 7, 1953 filing, with US 1,750,580 (Ebel) and US 1,498,697 (Scholle) being the most likely to bear on claim 1 and US 878,086 (Pearson) the least.

I'll ground this analysis in the actual cited references rather than working from memory. Let me pull the prior-art records.

Let me try to pull the actual text of the key references.

Obviousness analysis — US 2,744,497 A under 35 U.S.C. § 103

0. Evidence caveat — read this first

I was given the seven references of record (below) with their numbers, titles, dates, and assignees, which is the § 102(b) prior-art set the examiner actually applied. Within my tool budget I was unable to retrieve the full text or drawings of US 878,086; 985,047; 1,137,460; 1,221,355; 1,227,892; 1,498,697; or 1,750,580. One incidental retrieval did confirm an independent fact I use below: a design patent, USD 46,288, "Design for a feeder," Aaron B. Moe, filed Apr. 30, 1914, patented Aug. 18, 1914, assignor to Otis & Moe Manufacturing Company — corroborating that the "Moe" of US 1,221,355 (also assigned to Otis & Moe Mfg. Co.) was a commercial feeder manufacturer, not a one-off inventor.

The consequence: the element-by-element mappings below are hypotheses reconstructed from each reference's title, date, assignee, and field of art, plus the ordinary knowledge of this art. They are not quotations from the documents. Any mapping I designate as essential to a real § 103 contention must be verified against the actual text and drawings before it is relied on. I flag each such mapping with [verify]. What is reliable here: the claim language (from the authoritative full text), the reference identities and dates, and the legal framework.

1. Governing law for a 1953–1956 patent

• US 2,744,497 was filed Aug. 7, 1953 and granted May 8, 1956 — i.e., under the 1952 Patent Act, pre-AIA § 103. All seven references issued between Feb. 4, 1908 and Mar. 11, 1930, more than a year before filing, so every one is § 102(b) prior art with no swearing-behind or prior-art-date dispute available.
• The applicable test is Graham v. John Deere Co., 383 U.S. 1 (1966): (1) scope and content of the prior art; (2) differences between the prior art and the claims; (3) the level of ordinary skill; and (4) secondary considerations. Though Graham and KSR Int'l v. Teleflex, 550 U.S. 398 (2007) post-date this patent, they are the retrospective framework applied today, and KSR's "predictable variation / finite number of identified solutions / design incentive" reasoning is directly applicable to a mechanically simple farm implement.
• Do not confuse § 102 and § 103 here. Nothing in the record indicates any single one of the seven references discloses all elements of any claim; the examiner's allowance over exactly these references is affirmative (if rebuttable) evidence that no § 102 anticipation existed. The realistic attack is § 103 combination, and the "differences" to be bridged are narrow — which is precisely what makes the combination case strong.
• Practical framing: the patent expired May 8, 1973 and is unassertable. A § 103 analysis today is therefore defensive/academic — it matters chiefly if a later patent or a party relies on 2,744,497 as prior art, or in a historical reexamination-style review. It has no present infringement-enforcement significance (consistent with the litigation section's negative finding).

2. Level of ordinary skill in the art (PHOSITA)

A person of ordinary skill as of Aug. 1953 is best modeled as a competent farm-equipment builder / cabinetmaker or shop foreman with several years' practical experience constructing gravity-fed livestock and poultry feeders from readily available board stock — no engineering degree, and likely no formal training in fluid mechanics or bulk-solids handling. Notably, the specification itself confirms this level: the device "is preferably made of wood in readily obtainable board sizes, for the sake of convenience and economy." The claimed structure is a carpentry assembly — end walls, a back wall, a sloping bottom, a top wall, cleats, and a sliding board held by pins. That is squarely within a skilled builder's routine design repertoire, which lowers the § 103 bar for combining known feeder elements.

3. Scope and content of the prior art

All seven references are analogous art — they are drawn from the same field of endeavor (A01K 5/00–5/02, animal feeding devices and gravity replenishment from a hopper) and are all "feeders/troughs/hoppers/bins." The examiner's citation of all seven on the face of the patent concedes their analogousness. Their face-record characteristics:

Cross-reference to the prior sections: the plain-language claim breakdown and the observation that claims 2 and 3 are independent in form but add only a single structural feature each (pin-and-socket adjuster; depending partitions) are the linchpins of the combination case below. I do not repeat that analysis; I build on it.

4. The claims decomposed into elements

• Claim 2 = A–H + H defined as "vertically spaced sockets in said end edge of the regulating plate, and removable pins traversing said end wall and engaged in selected ones of the sockets."
• Claim 3 = A–H + partitions: "spaced partitions secured to and depending from said top wall forwardly of said regulating plate, said partition having rear edges with which said regulating plate is slidably engaged below said top wall."

5. Obviousness combinations, claim by claim

5.1 Claim 1 — the base gravity-metering structure

Primary theory (Combination I): Ebel '580 (or Scholle '697) in view of Darby '892.

• Ebel/Scholle as primary supplies a gravity hopper-and-trough feeder: end walls, a back wall, a bottom that slopes toward a trough, a top wall or hopper cover, and a feed-regulating gate whose height controls the flow of feed. [verify that the sloping bottom, the top wall with a forward-set rear edge (fill gap), and the guide-held slidable gate are all present.] If Ebel/Scholle shows a gate slidably held in side guide rails/cleats, element E is met and F/G follow.
• Darby '892 as secondary supplies the concept of a vertically adjustable plate/slide captured in vertical guides and held at a selected height to regulate the discharge of bulk material — i.e., the metering-by-gate-height concept and the guide/cleat mounting.
• Motivation: both are single-field (A01K; bulk material dispensing), both solve the identical problem (meter granular feed out of a reservoir at a controlled rate), and the builder would naturally adopt the proven guide-and-slide arrangement from a counter-bin to the hopper gate. KSR: predictable result, finite number of known gate-mounting options (rails, cleats, channels), ordinary mechanical skill.

Alternative theory (Combination II): Carlson '137,460 (hog trough with adjustable gate) in view of Scholle '697 / Moe '1,221,355.

• Carlson is the closest art in the swine genus and (per its title and era) would show a hog trough with an adjustable feed-regulating gate. [verify.] Scholle/Moe supply the gravity hopper and sloping-bottom reservoir that discharges into the trough. Together they render A–H obvious: the box (Pearson/Carlson), the sloping gravity floor (Scholle/Moe), and the height-adjustable gate (Carlson/Darby).
• Motivation: the field was actively seeking self-feeding swine equipment; combining a hog trough with a gravity hopper is the paradigmatic self-feeder, and the reference set shows the technique was known in poultry feeders for decades.

Anticipation risk: if any one of Scholle/Moe/Ebel already discloses a sloped-bottom hopper feeding a trough through a height-adjustable guide-held gate plus end/back/top walls, the claim is anticipated under § 102 and § 103 need not be reached. The examiner's allowance suggests the specific "cleats whose forward edges are spaced rearwardly of the top wall's rear edge, with the plate sandwiched between them" was the point of novelty — which is a mounting-location detail, exactly the kind of predictable structural variation KSR treats as obvious if any reference shows a slidably guided gate.

5.2 Claim 2 — the pin-and-socket height adjuster

Claim 2 differs from claim 1 only in defining H as vertically spaced sockets + removable pins through the end wall.

• Combination: Primary gravity feeder (Scholle/Ebel/Moe) in view of Darby '892. A counter-bin necessarily provides discrete, selectable height settings for a dispensing slide; pin-in-a-hole detent indexing is the standard, near-universal way to lock a sliding member at a selected height (the same mechanism used in farm gates, cribs, and wagon end-gates of the day).
• Motivation / predictability: choosing sockets and pins over a friction clamp, a wing-nut, or a set of notches is a selection among a small, well-known set of locking mechanisms with an expected result. KSR: "the combination of familiar elements according to known methods is likely to be obvious when it does no more than yield predictable results."
• Note the drafting vulnerability already flagged: claim 1's H is generic "mounting means." A device that adjusts height by any other means avoids claim 2 but not claim 1; conversely, a competitor that uses the pin-and-socket falls within both. This means claim 2 adds essentially no independent patentable weight beyond claim 1 — the very definition of obviousness-type overclaiming for this vintage, and it is why the pin/socket feature belongs in a dependent claim, not an independent one.

5.3 Claim 3 — the depending stall partitions

Claim 3 differs from claim 1 only by adding partitions secured to and depending from the top wall, forward of the regulating plate, whose rear edges the plate slidably engages.

• Combination: Primary gravity feeder (Scholle/Ebel/Moe) in view of Pearson '086 and/or McGinnis '985,047.
• Pearson '086 ("Feed-trough") and McGinnis '047 ("Combined feed-trough and rack") are expressly trough constructions and would show dividing partitions forming feeding stations. [verify.] Partitions in livestock/poultry troughs were ubiquitous by 1908–1911.
• Motivation: the specification itself states the partitions exist to "provide feeding stalls therebetween for different sizes and types of animals," and that any number can be used at any spacing. That is an admission that the partitioning is a known, optional, animal-size-selected feature — the classic "arrange parts to suit the user" rationale. Hanging partitions from the top wall so their rear edges also serve as a guide surface for the sliding plate is a simple doubling-up of function that a skilled builder would adopt to save wood and labor (the reference cites "readily obtainable board sizes" and economy). No unexpected result attends this addition.
• Claim-drafting note (building on the earlier section): claim 3's added subject matter is so narrow that a competitor can avoid it by omitting partitions while still reading on claim 1 — but for § 103 purposes that cuts against the patentee, because claim 3's incremental feature is exactly the sort of old, well-known trough feature (partitions) that a gravity-hopper reference + a trough reference would supply.

6. Motivation to combine — synthesized

1. Same field / analogous art. Every reference is an animal feeder, hopper, trough, or bulk-goods bin. No teaching-away argument is available from the record.
2. Same problem, same solution. Each reference addresses metering gravity flow of feed into a trough; the claimed invention does nothing more than arrange the known parts (reservoir, sloping floor, guide-held adjustable gate, retaining lip, partitions) into the known functional relationship.
3. Finite, enumerated design space. As of 1953 a builder had a small menu of choices for each element — box walls (any trough reference), sloping floor (any hopper reference), gate-height adjustment (rails, cleats, channels, pins, notches), and partitions (any trough reference). KSR makes selecting among such known options, with predictable results, obvious.
4. Design incentives and market forces. The record's "similar documents" list shows a dense cluster of related pig/piglet feeder patents in 1954–1958 (e.g., US 2,698,004 "Piglet feeding device"; US 2,749,881 "Feeder for little pigs"; US 2,834,320 "Pig feeder"), demonstrating strong contemporaneous demand and a rush to the same general solution — economic motivation to combine known elements into a weaning-pig self-feeder.
5. Predictable results / no unexpected behavior. The claimed arrangement simply yields a controlled gravity flow; the specification claims only simplicity, sanitation, adjustability, and reduced waste — all expected consequences of the combination.

7. Counterarguments a patentee (or the earlier section) would press — and my response

8. Bottom line

The strongest § 103 theory is a two- or three-reference combination in the same field: a gravity hopper-and-trough primary reference (Ebel '580 or Scholle '697; alternatively Moe '1,221,355) in view of a height-adjustable, guide-held metering slide (Darby '892, alternatively Carlson '1,137,460), and — for claim 3 only — in further view of a partitioned-trough reference (Pearson '086 or McGinnis '985,047). On that combination:

• Claim 1 is the base structure, each element of which is a known feeder component; the only plausible nonobviousness anchor is the specific cleat-sandwiched mounting location, a predictable mechanical variation.
• Claim 2 adds only pin-in-socket height indexing — a textbook selection among known locking mechanisms — and adds no weight beyond claim 1's generic "mounting means."
• Claim 3 adds only trough partitions — a ubiquitous, size-selected feature that the specification itself treats as optional — and similarly adds little.

My confidence is limited by the evidence caveat in § 0. I could not read the seven references, so I cannot responsibly state that any specific reference contains any specific element. What I can state with confidence: the claim set is structurally vulnerable because each claim's incremental feature is a small, well-known mechanical choice, and the references of record all sit in the same field solving the same metering problem. Before relying on any of this in a real § 103 contention, you must (a) obtain and read US 1,750,580; 1,498,697; 1,221,355; 1,227,892; 1,137,460; 985,047; and 878,086, and (b) confirm whether any single reference independently anticipates a claim (§ 102), which would make the § 103 analysis unnecessary. If you can supply those documents, I can convert the flagged [verify] mappings into an element-by-element chart.

Flagged for the record: I found no contradiction with the earlier sections. The prior sections' points that (i) no formal abstract exists, (ii) claims 2 and 3 are independent in form but narrow, and (iii) claim 1's generic "mounting means" is broader than claim 2's pin/socket, are all load-bearing for the analysis above, and I have built on them rather than restated them.