US 2797020

I'll check for any litigation/docket records and confirm the bibliographic data.

Search results for US 2,797,020 — and what they did not find

Litigation / CAFC check: I found no CAFC 2026 docket, district court action, PTAB proceeding, or any litigation record involving US 2,797,020. Targeted queries returned only unrelated documents sharing nearby identifiers:

• CA 2797020 A1 — "Elevator suspension and transmission strip" (Google Patents) — a different office/number.
• EP 2797020 A3 — "Proximity authentication system" (EPO Global Patent Index) — a different office/number.
• USD 362,378 — an unrelated design patent titled "Can opener" (Russell J. Schweizer).
• A general CAFC 2026 filing (Exafer v. Microsoft, apportionment/§284 damages) surfaced for the query "CAFC 2026 docket," but it has no connection to 2,797,020.

A direct search for the string "US2797020" returned zero results. Given the patent expired in 1974 (see below), the absence of any 2026 appellate activity is expected. Uncertainty noted: I cannot query USPTO PatentCenter/Global Dossier or the CAFC docket directly with the tools available; an absence of search hits is not proof of no litigation, only that no public record surfaced. The authoritative litigation check would be PatentCenter's "Legal Proceedings" tab plus the CAFC PACER docket.

Bibliographic summary (from the full text of US 2,797,020)

Abstract — important caveat: This 1957 patent prints no abstract of record. What appears on the Google Patents page under "Definitions" is an algorithmically extracted/garbled digest of the specification, not an official abstract. The nearest thing to an abstract is the stated object of the invention: a strip guide that, cooperating with a key-type container opener, lets the tear strip wind into a true spiral with its edges aligned, and that can be attached to the container together with the tear-strip key. The "prior art keywords" list (key, strip, stem, winding, guide) is likewise machine-generated.

The invention in context

The patent addresses the problem that when a key winds a metal tear strip off a vacuum-sealed can, the coil's edges can misalign — the resulting sharp edges can injure the user (a noted hazard), and the strip can twist or break, leaving the can only partly opened. Existing guides were unsuitable because they could not be shipped attached to the can with the key. Crowder's guide is a single bent-wire frame that slips onto the key stem, so key + guide go to market as one unit and stay flat against the can closure (no interference with stacking/packing). The frame may be wire or plastic, and need not be rectangular, but the two legs must be joined at each end and long enough to permit winding.

Independent claims in plain language

Claim 1 — A combination of (a) a tear-strip key having a winding stem and a finger grip and (b) a strip-winding guide. The guide is one single wire bent back on itself into a substantially rectangular closed frame. Its two parallel, spaced side members are arcuately curved in a plane perpendicular to the plane of the rectangle — i.e., the bends/bights hook around the key stem. The stem's axis is rotatably mounted on the concave side of those curves, midway between their ends, so that one half of the frame sits on one side of the stem and the other half on the other side. The wire's cross-section approximates that of the stem, so the frame can lie against the can and extend along it at the same elevation as the key.

Claim 2 — The same key-plus-guide combination, stated more specifically: a single wire bent into a substantially rectangular closed frame whose two substantially parallel spaced side members extend in a substantially common plane and substantially at right angles to the key stem. Each side member is coiled about the stem at its midpoint, splitting the frame half-and-half on either side of the stem. Those coiled portions form aligned bearings in which the key is rotatably mounted, and — a functional requirement not in claim 1 — the key's tear-strip-receiving slot lies in that portion of the stem between the two spaced side members, so the strip feeds onto the stem inside the frame.

Practical difference between them: claim 2 is the narrower, more definite recitation — it names the frame geometry (common plane, right angles to stem), the attachment as "aligned bearings," and locates the slot between the side members. Claim 1 is broader and functional-geometric, centering on the "concave side" rotational mounting and the equal-elevation/flat-laydown limitation.

Other items worth flagging

• Numbering-literalism conflicts in the source text. The specification reads "two opposite legs 15 and 17" while the frame itself is "generally indicated at 15" — the reference numerals in the printed description are internally inconsistent (legs 16 and 17 are almost certainly intended). I report them as printed and do not silently correct them.
• Claim 2 typographical error. The printed claim contains "the oher half of said frame," a typo in the original.
• Assignee. The patent is unassigned on its face (sole individual inventor). Google Patents' "Current Assignee: Individual" is consistent with that; no chain of title was verified.
• Geographic uncertainty. "Sharps Park, Calif." is not a locality I can confirm; treat it as an uncertain transcription of the original cover page rather than verified data.

I'll search for litigation involving US patent 2797020 across patent litigation sources.

Let me search more specifically across litigation databases and docket sources.

Let me check additional litigation-specific sources.

Litigation Search Results: US Patent 2,797,020

Bottom line: I found no evidence of any litigation involving US Patent 2,797,020. No case names, docket numbers, plaintiffs, defendants, jurisdictions, filing dates, or outcomes could be identified for this specific patent.

What I searched

I ran targeted queries against litigation-oriented sources and general web indices, including searches for the exact patent number combined with terms like "litigation," "infringement," "lawsuit," and "case," as well as queries aimed at the litigation portals you named (Unified Patents caselist, CAFC/PACER-type dockets) and secondary aggregators (CourtListener, Justia, Docket Alarm, RPX).

Important caveat on result quality (STRICT ID interpretation)

Every apparently relevant hit was for a different identifier, not US 2,797,020:

• EP 2797020 A3 — "Proximity authentication system" (a European application, unrelated).
• CA 2797020 A1 — "Elevator suspension and transmission strip" (a Canadian application, unrelated).
• A Korean patent document merely happened to contain the digit string "2797020" in a nucleotide-sequence line listing.

These are distinct from US 2,797,020 and I have excluded them. Per the strict rule, I am not treating these as matches.

Context from the patent record itself (why litigation is unlikely)

• Patent: US 2,797,020, "Can opener," inventor Jess S. Crowder (Sharps Park, Calif.).
• Filing date: March 4, 1953 (App. No. 340,238).
• Grant date: June 25, 1957.
• Assignee: Individual (no corporate assignee of record).
• Status: Expired — Lifetime; anticipated expiration June 25, 1974.
• Prosecution: Two claims; four prior-art references cited (Finney US 408,834; Rath et al. US 786,463; Epstein US 1,911,613; Snook US 2,612,287), none of which are litigation records.

The patent has been expired for over 50 years, the term ended in 1974 (i.e., a maximum ~17-year enforceable life from the 1957 grant), and it was held by an individual rather than an enforcement-oriented company. A product like a can-opener strip guide from that era would typically have produced, at most, a short-lived infringement action in the 1957–1974 window, and such mid-century district court cases are frequently not indexed in modern digital litigation databases.

Honest limitations

I cannot state with high confidence that litigation never existed, because:

1. Pre-1970s federal district court dockets are unevenly digitized; a 1957–1974 case would be difficult to surface through the sources above.
2. My searches were step-limited and returned mostly false positives on the number string.

What I can say with confidence is that no litigation involving US 2,797,020 appears in the sources searched. If you need a definitive negative, the remaining places to check would be the paper/PDF docket archives for the Central District of California (given the inventor's California residence) and a manual review of the USPTO's historical assignment and litigation records for the 1957–1974 period.

If you have a specific source (e.g., a Unified Patents or Docket Alarm case list) that you believe shows a case for 2,797,020, please share it and I will verify the case number, parties, and dates directly.

PTAB Activity Report — US Patent 2,797,020 ("Can opener")

Patent: US 2,797,020 A — Can opener
Inventor / Patent Owner: Jess S. Crowder (Sharps Park, Calif.); original assignee: Individual
Application No.: 15/340,238 (US340238A) — filed 1953-03-04
Granted / published: 1957-06-25
Statutory term end (anticipated expiry): 1974-06-25
Legal status on file: Expired – Lifetime
Source of record: https://patents.google.com/patent/US2797020/en

---

Proceedings overview

Total AIA trial proceedings on file: 0. There are no IPRs, PGRs, or CBMs against US 2,797,020 — no active, no claims-invalidated, no claims-sustained, no settled, and no institution-denied proceedings. Per the structured "PTAB proceedings on file" block (USPTO Open Data Portal ingest), the ODP returns no AIA trial proceedings for this patent, and I confirmed that with independent web searches of PTAB decisions and Federal Circuit dockets, which surfaced nothing. The bottom-line defensive posture is not "hardened" or "narrowed" — it is moot: this patent expired on 1974-06-25, roughly 52 years before today's date, and is not a live assertion target. Any demand letter citing US 2,797,020 is not a PTAB-defense problem; it is a patent-expiration problem.

---

Proceeding-by-proceeding detail

No proceedings to enumerate. Because the canonical structured block returns zero AIA trial proceedings, there is no docket number, petitioner, judge panel, institution decision, final written decision, settlement, or Federal Circuit appeal to report. I will not manufacture one. For completeness on the negative finding:

• Search performed: PTAB/ODP structured record; web searches for "2797020" IPR, US 2797020 Crowder PTAB, and "Jess S. Crowder" 2,797,020 litigation. All returned no PTAB or district-court hits on this patent. Results that mention a "2797020" are unrelated documents (e.g., CA 2797020 A1 for an elevator suspension strip; EP 2797020 A3 for a proximity authentication system) — do not conflate those with this US patent; the numbers coincide but the documents are unrelated.
• Why this is expected rather than a filing gap: AIA trials (IPR/PGR/CBM) apply to the patentability of claims, but the practical driver is a live or threatened assertion campaign. A patent whose term ended in 1974 cannot support a damages claim within the § 286 six-year lookback (which would have closed around 1980) and cannot be enforced today. There is no economic reason for any petitioner to spend the costs of an IPR on it.

---

Strategic summary

Claim status. The patent as issued contains claims 1 and 2 (both independent, combination claims: "In combination with a tear strip key…" — one drawn to the wire frame with arcuately curved side members rotatably mounted on the stem, the other to the same frame with coiled side-member bearings and a tear-strip slot between them). Because no IPR or PGR was ever filed, none of those claims was canceled, none was held unpatentable, and none was confirmed by the PTAB. There are therefore no "CANCELED" and no "SUSTAINED" claims on the PTAB ledger — the correct characterization is both claims 1 and 2 are UNTESTED at the PTAB, and in any event unenforceable-by-expiration. Note that claims 1 and 2 are combination claims; the guide frame itself is not claimed as a standalone article, which is one reason the claim set would be awkward to assert even if it were live.

Estoppel landscape (§ 315(e)(2)). There is no § 315(e)(2) estoppel on this patent, because estoppel attaches only to a petitioner who obtains an institution decision and a final written decision. With zero proceedings, no petitioner, privy, or real party in interest has been estopped from anything. Conversely, no AIA route remains useful now either: the term has run, so an IPR would buy a defendant nothing — even a fully successful cancellation decision would not eliminate an already-expired patent's historical estoppel/notice effects, and it could not wipe out past damages within a still-open recovery window (there is none).

Pattern signals. Not applicable in the usual sense: no serial petitioner, no repeat filer, no defensive aggregator (no Unified Patents, RPX, or other third-party filer in the chain), and no patent-owner appeal activity — the patent predates the existence of the Federal Circuit (est. 1981) and the AIA (2011) by decades. There is no continuation family to keep the dispute alive: the family record shows only the single US340238A application and the single US2797020A publication.

What the cited art tells you if you ever need it. The examiner-cited references of record are telling about how crowded this field was: US 408,834 (Finney, suspender-buckle, 1889-08-13), US 786,463 (Rath, cross-line buckle, 1905-04-04), US 1,911,613 (Epstein, "Can opener key and strip guide," 1933-05-30), and US 2,612,287 (Snook, "Can tear strip guide and measuring cup," 1952-09-30). The "Similar Documents" set is even more directly on point — e.g., US 2,572,2820-era neighbors such as US 2,572,820 ("Guide for can-opening keys and tear strips," 1951-10-23), US 2,542,116 ("Guide for can opening key and tear strip," 1951-02-20), US 2,741,394 ("Tear strip guides," 1956-04-10), US 2,769,567 ("Can opener key and strip guide," 1956-11-06), and US 2,738,099 ("Key type can opener," 1956-03-13). That is a dense cluster of near-simultaneous art on exactly the same problem. Had this patent been asserted in the 1950s–60s, § 103 challenges grounded in Epstein and Snook plus the co-pending guides would have been the obvious attack. This is historical analysis only — it is not a live PTAB opportunity.

---

Recommended next steps

1. If you received a demand citing US 2,797,020: do not build a PTAB strategy. Respond on term. The patent's term ended 1974-06-25 (anticipated expiration per the ODP record; the application was filed 1953-03-04 and granted 1957-06-25, so the 17-year pre-URAA term ran from 1957-06-25 with maintenance/fee effects recorded as "Expired – Lifetime"). Under 35 U.S.C. § 271 and the § 286 six-year damages lookback, there is no recoverable infringement window. Any assertion is meritless on its face, and a demand built on claims 1–2 would be the basis for fee-shifting or a § 285 exceptional-case argument.
2. Do not cite a PTAB FWD as support — there isn't one. There is no institution decision, no final written decision, and no Federal Circuit appeal to link. If opposing counsel claims a PTAB result exists for this patent number, ask for the proceeding number and verify it in USPTO PTAB E2E (https://e2e.uspto.gov) or the PTAB decisions library (https://www.uspto.gov/patents/ptab/decisions); a nonexistent number will end the conversation. The Google Patents family record for US 2,797,020 lists no PTAB proceedings, consistent with the ODP block.
3. Verify lapse independently before you act. The "Expired – Lifetime" status in the ODP/Google Patents record is an assumption-based legal-status field (as Google itself notes). The authoritative check is USPTO Patent Center / Assignment records for application 15/340,238 and the maintenance-fee history — for a 1957 patent the relevant step is simply confirmation that the statutory term lapsed in 1974, which no maintenance payment could extend (and for a pre-1995 patent, no post-1974 revival would restore an expired term against intervening rights, 35 U.S.C. § 41(c)/§ 252 estoppel principles).
4. Check for reissue or reexamination history. A 1957 case could in principle have a reissue (which would extend/alter claims) — none appears in the family record, but if you need a clean chain, pull the full file wrapper via Patent Center before any settlement or dismissal with prejudice. No ex parte reexamination, no reissue, and no certificate of correction on claims 1–2 appear in the record I retrieved.

Confidence statement: I am highly confident there are zero AIA trial proceedings on US 2,797,020. I could not find any District Court litigation, ITC investigation, or Federal Circuit appeal involving it either. If a proceeding was filed very recently (after the ODP ingest), it would not appear in the structured block — but given the 1974 expiry, that is not a realistic scenario, and my web searches surfaced nothing to contradict the "no PTAB activity on file" default.

I'll research the assignment record for US 2,797,020 across the sources you named.

Assignment & Ownership Analysis — US Patent 2,797,020

Bottom line up front: the USPTO assignment record for US 2,797,020 is empty. The authoritative Google Patents legal-events record (the copy supplied in the source text) shows only the four events you would expect from a solo-inventor filing — application filed, priority claimed, patent granted, and anticipated expiration — and not a single "Assignment" event. The patent issued to the inventor as an individual with no assignee of record.

Sourcing note / limitation: I was unable to open an interactive session against assignmentcenter.uspto.gov or assignment.uspto.gov to run the patent-number query directly (the search interface is not reachable by query-string here). My negative finding therefore rests on (a) the authoritative legal-events record in the supplied patent text, which contains no assignment entries, and (b) web searches for the patent number plus "assignment / reel / frame / Crowder," which returned no assignment record. I could not retrieve a reel/frame number because none appears to exist. Treat the "no assignments" call as high-confidence but not machine-verified against the Assignment Center UI itself.

---

Inventors

• Sole inventor. The patent names only Crowder; there are no joint inventors.
• Employer: The patent carries no corporate assignee, no "assignor to" recital, and no government-interest statement. There is nothing in the record indicating Crowder was under an obligation to assign to an employer. Absent an assignment document there is no evidentiary basis to name an employer, and I will not guess one.
• Unusual-pattern check: The typical "inventors departed the original assignee before filing" trigger is not applicable — there was no original corporate assignee to depart from. The patent is a pure individual-inventor filing.

---

Original assignee

No assignee of record. The patent issued to the inventor personally.

• Google Patents lists Original Assignee: Individual and Current Assignee: Individual, i.e. the field is populated by the inventor himself rather than a company.
• Product embodying the claims: Unclear. The specification describes the strip-winding guide as a low-cost wire frame "adapted to be mounted in position upon such a key," intended to add "little expense to the equipping of each can with a separate guide." That is the language of a component meant to be supplied with commercial tear-strip cans, but the record shows no manufacturer, no licensee, and no commercial product identified with Crowder.
• Primary line of business / current status: Not determinable from the patent record. An individual inventor residing in a small California locality is not a corporate entity with a status that can be looked up; I have no reliable source confirming any product, business, or later corporate vehicle.
• Enforcement relevance today: The patent is Expired – Lifetime, with an anticipated expiration of June 25, 1974 (i.e. the full pre-URAA 17-year term from the 1957 grant). It has been unenforceable for over five decades, so ownership is of historical interest only.

---

Assignment timeline

There are no recorded assignments for US 2,797,020.

• No pre-issuance assignment to an employer or company appears in the record.
• No post-issuance assignment appears in the Google Patents legal-events list.
• No reel/frame, conveyance type, assignor, assignee, execution date, recording date, or correspondent of record can be reported, because no assignment document was filed against this patent (at least none surfaced in the sources searched).

Per your instruction, I am stating this plainly and stopping the chronological enumeration here — the absence of records is the finding: the patent remained in the inventor's name, and it expired on 1974-06-25.

---

Timeline diagram

timeline
    title Ownership of US 2797020
    1953 : Filed by Jess S Crowder
    1957 : Patent issued to Crowder as individual
    1974 : Patent expired

(No assignment events are available to stack under any year, because none were recorded.)

---

NPE / troll-pattern signals

---

Verdict

Insufficient data — specifically, no recorded assignments exist; the patent never left the original individual inventor's name of record.

The Google Patents legal-events record for US 2,797,020 contains only the filing (1953-03-04), grant (1957-06-25), and anticipated expiration (1974-06-25) events, with Current Assignee listed as "Individual" and no reel/frame entries of any kind. There is therefore no shell-entity transfer, no asserter in the chain, no repeat correspondent, and no defensive-aggregator endpoint to evaluate — the NPE analysis is not merely negative, it is inapplicable because no ownership change was ever recorded and the patent has been expired since 1974.

Verify at: the USPTO Assignment Center search page, https://assignmentcenter.uspto.gov/ (search patent number 2797020; expected result: no records), cross-checked against the Google Patents legal events at https://patents.google.com/patent/US2797020/en.

Flag for the record: This section does not contradict the earlier litigation section — both converge on the same picture (individual inventor, no corporate owner, expired 1974). The one thing I could not do is query the Assignment Center's underlying database directly, so if your workflow requires a machine-verified "no records" hit, that single query should be re-run interactively before the finding is finalized.

I'll research each cited reference and the closest "similar documents" to build the prior-art analysis.

Let me retrieve the two patents for which I still need specifics, plus the closest "similar documents."

Prior-Art Analysis for US 2,797,020 ("Can opener," Jess S. Crowder)

0. Scope, sources, and a transparency note

Building on the bibliographic summary and litigation section already generated, this section focuses only on the prior art.

Search-execution caveat (please read before relying on the negatives below): My live lookups were cut off after I retrieved full text for the Finney buckle, the Snook guide, and partial text for several "similar documents." I was unable to pull the full text of US 1,911,613 (Epstein) and US 786,463 (Rath) before the tool budget was reached. Where I describe those two, I distinguish what is verified from what is inferred from the title/classification, and I do not fabricate structure. The patent's own full text (authoritative, per the source) is used for all dates and claim language.

One numbering-literalism point carried forward: the target is US 2,797,020 A (the "A" kind code included). I did not substitute any other number, and I excluded EP 2,797,020 and CA 2,797,020 as different-office identifiers, consistent with the earlier sections.

---

1. The four references of record on the face of the patent

All four were cited by the examiner and appear in the "References Cited" list. Dates below are as printed on the patent / as listed by Google Patents; OCR variants are flagged rather than corrected.

Date caveats: (a) The Finney OCR is internally inconsistent — one capture reads the patent as "dated August 18, 1889," while the Google Patents text and citation table read "Aug. 13, 1889." I report Aug. 13, 1889 and flag the OCR variant. (b) Google Patents' citation table anomalously lists Finney's "priority date" as 1889-08-13 (i.e., it echoes the publication date). Treat the true filing date as April 25, 1889.

---

2. Reference-by-reference description and claim mapping

R1 — US 408,834 (Finney, 1889), "Suspender-Buckle" — verified full text

What it discloses (verified): A suspender buckle whose frame "consist[s] of a single piece of wire, having loops or eyes a formed by twisting the wire at the center of the respective side bars." A cross bar or pintle is "loosely journaled in the eyes a." A separate latch frame "formed of a single piece of wire" is looped about the top bar.

Why the examiner cited it: It is the structural archetype of the claimed frame — one continuous wire bent into a closed frame with loops at the midpoints of the side members that serve as bearings/journal points. Finney's "loops or eyes a … at the center of the respective side bars" is structurally the ancestor of Crowder's "loops 18" / "coiled portions … forming aligned bearings."

§ 102 anticipation of claims 1–2? No. Finney is a buckle, not a tear-strip key. It lacks every claim-1 element that makes the combination a can-opener: (i) a "tear strip key having a winding stem and a finger grip"; (ii) the stem axis "rotatably mounted on the concave side of said side members"; (iii) "arcuately curved in a plane perpendicular to the plane of the rectangular [frame]"; and (iv) the "cross-sectional size approximating that of the stem." A single-reference anticipation requires disclosure of every claimed element; Finney supplies only the bare wire-frame/eye geometry. Relevant art for the frame structure only — § 103 territory, not § 102.

---

R2 — US 786,463 (Rath et al., filed 1904, issued Apr. 4, 1905), "Cross-Line Buckle" — structure not verified

What I can state: It is a buckle (per title and classification), filed Feb. 5, 1904, issued Apr. 4, 1905 — i.e., roughly contemporaneous in art with Finney and in the same buckle classification. I was unable to retrieve its claims or drawings, so I will not assert a specific structure.

Why it appears on the face: Most likely as a second buckle/strap-frame reference reinforcing the same bent-wire closed frame with loops/eyes as bearings concept, i.e., a secondary structural reference paralleling R1.

§ 102 anticipation of claims 1–2? No — and even on the most favorable reading of a buckle it cannot anticipate, because a buckle cannot disclose the recited "tear strip key having a winding stem and a finger grip." Honest limitation: the absence of a verified structure means I cannot rate its § 103 weight precisely; its citation on the face, paired with Finney, indicates the examiner treated it as cumulative wire-frame/buckle art.

---

R3 — US 1,911,613 (Epstein, May 30, 1933), "Can opener key and strip guide" — closest art of record; text NOT retrieved

What I can state with confidence: The title is directly on point — the same field and the same problem as the target patent (a key plus a strip guide). It is independently cited by at least one later can-opener key patent — Hertzfeldt, US 2,780,387, "Key and can support for removing sealing bands from vacuum cans" — which lists US 1,911,613 among its U.S. Patent References (FreePatentsOnline). That corroborates it as a genuine, relevant strip-guide/key reference in the 1930s art.

§ 102 anticipation — assessment, with explicit uncertainty: This is the one reference of record that could plausibly come closest to the claims, because it recites both a key and a guide. However, claims 1 and 2 do not claim any guide; they claim a very specific one — a "single wire member bent upon itself … into a substantially rectangular closed frame" whose parallel side members are "arcuately curved in a plane perpendicular to the plane of the rectangular [frame]" / "coiled about the key stem" at their midpoints, forming "aligned bearings." Unless Epstein discloses that exact bent single-wire frame with midpoint coiled bearings, it cannot anticipate under § 102. Given the 1933 date and the guide art of that era, a wire-frame-with-midpoint-coils disclosure is possible but unconfirmed. I therefore state:

• Cannot confirm § 102 anticipation. If Epstein's guide is a bent-wire rectangular frame with the stem journaled at the midpoints of its side members, it would anticipate at least claim 1; if it is any other guide form (slotted plate, U-clip, etc.), it is at most § 103 art.
• Flag: I recommend retrieving the Epstein drawings/claims from PatentCenter before finalizing any anticipation position; my tool budget cut this off.

---

R4 — US 2,612,287 (Snook, filed Apr. 4, 1950, issued Sept. 30, 1952), "Can tear strip guide and measuring cup" — verified full text

What it discloses (verified): A can-opener guide ("member") with a closed longitudinal slot that guides the coil of winding band as it is detached and coiled about a key; the member has a can-contacting surface ahead of the slot and "clip means transverse to and adjacent said slot and in registry therewith to rotatably receive and removably retain a key." In the commercial form it is a molded-plastic or metal body doubling as a measuring cup, with a bifurcated (U-shaped) tail forming a clip recess and keyhole to retain the key. Claim 1 (granted) recites: "a member having a closed longitudinal slot … to guide the coil … and clip means … to rotatably receive and removably retain a key."

Overlap with the target: This is the reference most closely aimed at the same problem — guiding the coiled strip and rotatably mounting/retaining the key so the coil cannot slip axially. Snook even recites "rotatably receive" and "immediate disposal of said key and wound band," overlapping the functional spirit of Crowder's claims.

§ 102 anticipation of claims 1–2? No. The structures are materially different:

• Claim 1 requires the guide to be "a single wire member bent upon itself … into a substantially rectangular closed frame," with the stem axis on the concave side of arcuately curved side members. Snook is a slotted plate/cup body with a bifurcated U-clip, not a bent-wire rectangular frame.
• Claim 2 requires the side members to be "coiled about the key stem" at their midpoints, forming aligned bearings, with the key slot between the spaced side members. Snook's clip is an integral bifurcated recess, not a pair of midpoint coils on a closed wire loop, and it does not place the key's slot between two frame side members.
• Neither claim 1 nor claim 2 reads on Snook's element-for-element. Strong § 103 art (same problem, similar function, different structure); not § 102.

---

3. Beyond the record: materially relevant pre-filing art the examiner did NOT cite

The Google Patents "Similar Documents" list surfaces several key/guide patents that are more closely analogous than the two 1889–1905 buckles and that bear directly on claims 1–2. The most important are the pre-filing ones:

• US 2,542,116 — "Guide for can opening key and tear strip," issued Feb. 20, 1951 (pre-filing).
• US 2,572,820 — "Guide for can-opening keys and tear strips," issued Oct. 23, 1951 (pre-filing).

Both issued before the March 4, 1953 filing date and sit squarely in the tear-strip-guide field. I was unable to retrieve their texts within the search budget, so I cannot assess their structure or anticipation weight — but on their dates alone they are § 102/§ 103 art that was apparently not before the examiner, which is a notable gap in the record. Flag for follow-up.

A second cluster issued after the March 4, 1953 filing but may share a pre-filing priority/filing date (possible § 102(e) art): US 2,710,111 ("Can opener," Jun. 7, 1955); US 2,738,099 ("Key type can opener," Mar. 13, 1956); US 2,741,394 ("Tear strip guides," Apr. 10, 1956); and US 2,769,567 ("Can opener key and strip guide," Nov. 6, 1956). I retrieved partial text for US 2,769,567, which discloses a combined key-and-strip-guide of sheet metal (a U-shaped member with legs straddling the strip, not a bent-wire frame) whose "oppositely disposed parallel portions [are] adapted to be disposed adjacent opposite faces of the coil." That reference's structures again differ from the claimed single-wire rectangular frame. Their filing dates are unverified here — the ones filed before Mar. 4, 1953 would be § 102(e) art; the rest are at most § 103 background. Flag for follow-up.

---

4. Bottom line on anticipation

Overall finding: On the verified texts, none of the four references of record anticipates either claim. Anticipation of claims 1–2 requires a single reference that discloses the combination — a tear-strip key (stem + finger grip) and the specific single-wire, substantially rectangular, closed frame whose parallel side members are arcuately curved/coiled at their midpoints to form aligned bearings journaling the stem, with the key slot between the side members. The buckles supply only the bare frame-with-loops idea; Snook supplies the key-retaining-guide idea; only Epstein (R3) might supply both, and I could not verify its structure. If any of-record reference anticipates, it is Epstein, and verifying it is the single highest-value next step.

Two honest caveats: (1) I could not retrieve R2 or R3 full text, so the "no anticipation" conclusion for those two rests on their titles/classifications plus the claim language, not on a completed element-by-element comparison — treat it as provisional pending document retrieval. (2) The pre-filing guides US 2,542,116 and US 2,572,820 are potentially closer art than anything of record and were not cited; per the strict-instruction rule I did not assume their content, but they warrant direct retrieval from PatentCenter before any validity position is finalized.

If you can supply or permit retrieval of the Epstein, Rath, US 2,542,116, and US 2,572,820 texts, I'll complete a formal element-by-element § 102 chart for each claim.

I'll research the cited prior-art references to ground the § 103 analysis in what they actually disclose.

Let me pull details on the two most field-relevant references and the closest analogous guide art.

Obviousness Analysis — US 2,797,020 ("Can opener," Crowder) under 35 U.S.C. § 103

A note on framing before the substance: this is a retrospective obviousness analysis. The relevant legal question is whether the subject matter of claims 1 and 2 would have been obvious to a person having ordinary skill in the art as of the invention date (here, the March 4, 1953 filing date), in view of art that predates it. Because the application was filed in 1953, pre‑AIA § 103(a) governs — the "at the time the invention was made" standard of Graham v. John Deere, 383 U.S. 1 (1966), as refined by KSR Int'l v. Teleflex, 550 U.S. 398 (2007).

Flagged instruction conflict (per the cross-reference rule): the system context gives today's date as 2026‑09‑30, while this task states April 26, 2026. The discrepancy does not affect the analysis; I note it rather than silently reconciling it.

---

1. The legal framework I am applying

1. Scope and content of the prior art — limited to art that predates March 4, 1953, plus art qualifying under pre‑AIA § 102(e) (U.S. applications/patents with earlier effective filing dates).
2. Differences between the prior art and the claims — element-by-element.
3. Level of ordinary skill in the art — see below.
4. Secondary considerations — none of record; I found no evidence of commercial success, long-felt need, copying, or industry praise attributable to this patent (and the prior litigation sweep in the earlier section found no case record).

Under KSR, a rigid teaching–suggestion–motivation requirement is rejected: the motivation may come from "any need or problem known in the field," "design incentives and other market forces," and "the effects of demands known to the design community." A combination of familiar elements according to known methods, yielding predictable results, is obvious. KSR, 550 U.S. at 415–17, 421.

Level of ordinary skill (my construction): a mechanical designer/mechanic of ordinary creativity with roughly 2–4 years of experience in sheet-metal container closures and tear-strip hardware, familiar with low-cost wire-forming and stamping. The device is not high-technology; the art is mature and the design space is small.

Threshold observation that matters a great deal: both claims are combination claims in which the "tear strip key having a winding stem and a finger grip" is admitted prior art. The specification itself says "[a] typical winding key is indicated at 10, this including a finger grip portion 11 and a stem 12 having a slot 13 therein," and describes it as what is "generally employed." That admission removes the entire key half of each claim from the novelty/obviousness inquiry and leaves only the guide's geometry. In re Fout, 675 F.2d 297 (CCPA 1982) (admissions in the specification are prior art against the applicant).

---

2. The references on the page, and what each actually teaches

A. Cited of record (4 references)

B. "Similar Documents" on the page with pre‑filing publication dates

These are on the page and two of them predate the 1953 filing, so they are § 102(a)/§ 103 art and are fair game:

The remaining "similar documents" are dated 1955–1956 (e.g., US 2,710,111; US 2,739,099; US 2,741,394; US 2,769,567; US 2,811,051) and therefore are not § 102(a) art against a March 1953 filing. They could only qualify under § 102(e) if their underlying applications were filed before March 4, 1953 — a fact I cannot verify from the page. I flag them and do not rely on them as primary references.

C. Two uncited references surfaced in searching (explicitly outside the page's prior-art list)

I am reporting these because they are strongly on point, but they are not in the page's "Patent Citations" or "Similar Documents," so they are not part of the sanctioned record here. I would want their filing dates before relying on them:

• US 2,744,653 ("Can opener," issued May 8, 1956) — a frame member 25 with a central rectangular opening 26, "bearings 27 in opposite side walls thereof in which the key is journaled for rotation with the slot 23 located centrally at the opening 26," a forward edge 28 that engages under the can rim, and a flattened key end 30 soldered to the can and broken off at a weakened line 32. That is functionally the claim‑2 architecture in stamped-plate form.
• US 2,758,746 (issued Aug. 1956) — a guide A with an opening 22 and ribs 26 having aligned openings 27 rotatably supporting the key 14, spot-welded to the can cover, with the express stacking consideration that the guide's upper edge lies below the lip so cans stack.

---

3. Element-by-element mapping

Claim 1

Claim 2

Observation: Claim 2's added limitations are, with one exception, exactly the Finney structure — mid-side loops forming aligned bearings — plus a slot-location requirement that 2,744,653 and Snook supply. Claim 2 is the more vulnerable claim of the two, not the less.

---

4. Combination 1 (primary): Epstein '613 + Finney '408,834

The combination. Epstein, "Can opener key and strip guide" (1933), supplies the entire field-specific half of the claim: a tear-strip key with a strip guide, in the same classification, addressing the same coiling problem. Finney supplies the mechanical expedient that distinguishes Crowder: a single bent wire closed frame with loops at the midpoints of the side bars that journal a stem, splitting the frame half-and-half.

Motivation to combine, as a PHOSITA in 1953 would have articulated it:

1. Same field, same problem. Both Epstein and Crowder are directed to guiding a tear strip as it is coiled on a key. That is the strongest possible motivation category — the artisan is already working in this exact niche.
2. The guide art was actively looking for cheaper, flatter guides. Crowder's own specification concedes the point: "Since the guide frame is made of a wire-like member, it adds little expense to the equipping of each can with a separate guide." A statement of economic advantage in the specification is itself evidence of the design incentive that would have driven the artisan to a wire form. KSR expressly credits "design incentives and other market forces."
3. Wire-eye bearings were a notorious, familiar mechanical expedient. Finney's frame-with-twisted-eyes-journaling-a-bar construction (1889) is a standard, decades-old way to make a low-cost pivot. Combining a known pivot expedient with a known guide frame is "the combination of familiar elements according to known methods," which KSR makes presumptively obvious where results are predictable.
4. Predictable result. Swapping a stamped/plate guide for a bent-wire frame of comparable cross-section yields no new mode of operation — it still journals a stem and confines a coil. Nothing unpredictable happens.
5. The "ship it on the can" requirement. Crowder's stated object (a guide "which can be attached with the key to the container") is not a new problem — Snook's guide is expressly "very easily detached and re-used," and both US 2,744,653 and US 2,758,746 teach guides soldered/spot-welded to the can with the key and lying flat so cans stack. A PHOSITA facing the packing/stacking constraint had every reason to select the flattest, thinnest available frame — a wire frame.

---

5. Combination 2 (alternative): Snook '612,287 + Finney '408,834

Identical logic, with Snook as the primary reference. Snook is particularly useful because it (i) rotatably receives and removably retains the key, (ii) provides lateral/axial support against the coil "slipping to one side," which is precisely the misalignment defect Crowder recites, and (iii) expressly addresses hazard shielding ("it also acts to shield the sharp edges of the unwinding band and coil, thereby preventing hazards due thereto") — the same safety rationale in Crowder's specification. Substituting Finney's wire-frame-with-eyes for Snook's slotted plastic/metal body is a mere substitution of one known frame construction for another with predictable results.

---

6. Combination 3 (further): Finney (or Rath) + the tear-strip-guide line (US 2,572,820; US 2,542,116; and, if dates qualify, US 2,744,653 / US 2,758,746)

This is the combination I judge most likely to invalidate claim 2:

• US 2,744,653 teaches the entire functional architecture of claim 2 in plate form: a closed frame (25), a central opening (26) for the coil, bearings (27) in opposite side walls in which the key is journaled, the key slot (23) located centrally at the opening, an edge (28) engaging the can rim, and a soldered, break-away attachment to the can.
• Finney teaches replacing the plate frame with a single bent wire frame whose side bars carry the bearings as loops at their midpoints.
• Motivation: weight/cost reduction, thinner profile for stacking, and the express desirability of a guide that "adds little expense" (Crowder's own admission). One of ordinary skill would predict that a wire frame with mid-side loops will journal the stem exactly as the plate frame's bearings do. Result: claim 2.

Caveat I will not paper over: US 2,744,653 and US 2,758,746 are not in the page's prior-art section, and I have not verified that their applications were filed before March 4, 1953. If their effective filing dates postdate Crowder's, they are not § 102(e) art and this combination collapses. Treat it as a lead requiring date verification, not as a settled conclusion.

---

7. Where the obviousness case is weakest (arguments a patent owner would press)

I would not represent these claims as a slam-dunk invalidity. Honest counterweights:

1. The "arcuately curved in a plane perpendicular to the plane of the rectangular" limitation (claim 1). Finney's disclosure is "twisting the wire at the center of the respective side bars" (italics mine) and Fig. 4's "ends of the pintle ... looped around the frame." Neither is an express recitation of a loop lying in a plane perpendicular to the frame plane. The literal reading matters under the strict-ID rule, and Crowder's claim 1 wording is a specific geometric orientation. A patent owner would argue the perpendicular-plane arcuate curve is the inventive contribution and that Finney's twisted eyes are a different geometry. This is the single most contestable limitation in the patent.
2. Analogous art challenge to Finney and Rath. Both are buckles — a different field of endeavor. Under In re Bigio, 381 F.3d 1320 (Fed. Cir. 2004) and In re Clay, 966 F.2d 656 (Fed. Cir. 1992), a buckle reference is available only if it is "reasonably pertinent to the particular problem with which the inventor is involved." A patent owner would argue that suspender and cross-line buckles are not pertinent to tear-strip coiling, and that Finney's pintle is a fixed cross-bar rather than a rotatable winding stem that must be break-away mountable to a can and rotated under load. The counter is that the problem actually solved by Finney's structure — rotatably mounting a bar in a wire frame with midpoint loops — is precisely the sub-problem Crowder faced, and KSR cautions against over-rigid field-of-endeavor tests. This is a genuine fight, not a formality.
3. No verified primary reference showing the closed wire frame in the guide context. Because I could not retrieve the full text of Epstein '613, Rath '786,463, US 2,572,820, or US 2,542,116 in this session, I cannot state with high confidence that any single reference discloses a tear-strip guide whose frame is a bent wire. If none does, the obviousness case rests on a two-reference combination, which is still proper under § 103 but is weaker than a single-reference case.
4. The dimensional limitation ("cross-section approximating that of the stem ... same elevation as the key"). A patent owner would argue this is not routine optimization but a functional requirement tied to stackability/packing. KSR answers that dimensional selection for a known purpose is obvious absent criticality; Crowder shows no criticality data (no comparative testing, no unexpected results).

Secondary considerations: I found none in the record or in the earlier litigation sweep. No evidence of commercial success, licensing, copying by competitors, or long-felt but unmet need is associated with this patent. The absence of secondary considerations cuts against the patent owner.

---

8. Limitations on this analysis (stated explicitly, as required)

• I could not obtain the full specification text of US 1,911,613 (Epstein) or US 7 86,463 (Rath et al.) during this session; my statements about them rest on their titles, their citation context in later patents (US 2,744,653; US 2,769,567), and the general character of the art. Any element-by-element mapping onto Epstein or Rath should be re-verified against their full texts before being relied upon.
• The file histories of US 2,797,020 and of the cited references are not available to me here. A § 103 opinion of record strength requires the examiner's rejections, applicant's arguments, and any affidavits (Rule 131/132) in the file wrapper.
• "Sharps Park, Calif." in the bibliographic data remains an unconfirmed locality (flagged, not corrected), and I have no third-party or docket confirmation for the inventor's identity beyond the patent face.
• The KSR-era framework I apply is being used retrospectively to a 1957 patent. A contemporaneous examiner applying the mid-century "invention" standard might well have allowed these claims; the analysis above is the modern, more combination-friendly standard.
• Practical reality check: the patent expired June 25, 1974 and is unenforceable. This § 103 question is therefore not a live invalidity defense but a prior-art/validity study question — most plausibly relevant if US 2,797,020 is being cited as art against a later patent, or in a historical/portfolio assessment.

---

9. Bottom line

• Claim 1 is probably obvious over Epstein '613 (key + strip guide) in view of Finney '408,834 (single-wire frame with mid-side eyes journaling a stem), with the motivation supplied by the same field, the same coiling/hazard problem, the admitted prior art status of the key, and the express cost/flatness/stacking design incentives. The weakest limitation is the "arcuately curved in a plane perpendicular to the plane of the rectangular" geometry, which Finney teaches only by implication ("twisting ... at the center of the side bars").
• Claim 2 is more clearly obvious — its added limitations (common-plane side members at right angles to the stem, mid-side coils forming aligned bearings, slot between the side members) are the verbatim substance of Finney's eyes-journaling-a-pintle, with the slot location supplied by Snook '612,287 (registry of guide slot and key retainer) and, if its date qualifies, by US 2,744,653 ("slot 23 located centrally at the opening 26").
• Highest-confidence combination: Snook '612,287 + Finney '408,834 (both verified, both pre-date the filing).
• Highest-invalidity-potential lead, pending date verification: US 2,744,653 + Finney (the 2,744,653 reference is not on this page's prior-art list and its filing date is unverified).
• Confidence: moderate — not high — because the strongest claim-1 limitation is met only impliedly by the cited art, and the two most on-point field references (Epstein and Rath) could not be read in full here.