US 2271159

I'll run targeted searches for this patent number, then summarize.

Now let me check for any CAFC litigation or 2026 docket activity involving this patent.

US 2271159 — Verification and Summary

Search scope note: I searched for the literal string "2271159" / "2,271,159" paired with USPTO and CAFC 2026 docket terms. I found no CAFC (Federal Circuit) 2026 docket entry, appeal, or ITC/assignment-record activity for this patent number. Search results for "2271159" otherwise return non-U.S.-patent uses of the same digits (a Canadian application CA 2271159, an EU patent 2271159, UK trademark journal entries, a Brazilian STJ case, and unrelated commercial/vehicle part numbers) — these are not US 2271159 and I have excluded them. I do not have authoritative information affirmatively confirming that a CAFC docket was checked exhaustively; I can only report that no such 2026 docket activity surfaced.

Bibliographic data (from the patent text provided and Google Patents/FPO records)

Note on priority/filing dates: Google Patents lists the prior-art date, filing date, and priority date uniformly as 1940-05-13 (the application filing date); there is no earlier foreign priority indicated.

Abstract — important caveat

This patent has no formal abstract. It issued in 1942, before abstracts became standard practice on U.S. patents, and the Google Patents page reproduces no abstract field (the "Definitions" text on that page is an auto-extracted excerpt, not the patent's own abstract). Any "abstract" must therefore be synthesized from the specification. A faithful synthesized statement:

A coupling for joining abutting tubes (or a tube to a fitting) in flush, projectionless fashion, comprising a rotatable, internally reversely threaded nut acting turnbuckle-fashion on two oppositely threaded screws, each screw carrying a rubber-like axially compressible, peripherally expansible plug that grips the tube's inner wall; a slotted spacing sleeve abuts the plugs and the tube ends, a washered ring separates the tube ends, and spanner access to the nut is gained through openings in the sleeve and ring, so that turning the nut draws the tube ends together and expands the plugs without requiring rotation of either tube.

Technical disclosure in brief

• Field/context: rails for hospital cubicles, shower curtains, etc., where trolleys must roll over a smooth, uninterrupted joint. It expressly criticizes the set-screw practice of the Patent to C. P. Day, No. 2,008,579 (patented July 16, 1935) as insecure on light-gauge tube walls and liable to loosen into projections.
• Key components (reference numerals as in the patent): coupling sleeve 14 (longitudinally slotted as at 20, notched at 22), operating nut 15 with spanner slots 23, reversely threaded screws 16 and 17, expansible members 18 and 19 (axially bored rubber/ resilient plugs), eye 26 on each screw seating in oval seats 27 of washers 28 notched at 29, thrust washers 30, and end ring 31 with opening 32 for tool access.
• Anti-rotation of the screws is achieved by keying washers 28/30 to the inwardly projecting seam rib/key 13 of the seamed tubes (10, 11), so nut rotation produces only axial screw movement. The patent notes that with seamless tubing, frictional grip of the expanded plugs can substitute for the keys.
• The design is "flush" (no holes, taps, or outer projections on the tubes) and is stated to be usable with oval/non-round tubing and for coupling tubing to a bracket or fitting.

Plain-language overview of the claims

All six claims read as independent (none uses "The coupling of claim …" dependency language). Two of them, 4 and 6, are close paraphrases of one another.

Claim 1 — The base combination: a rotatable member; two reversely threaded elements engaged with it for opposed axial movement; axially compressible/peripherally expandable plugs carried on those elements with non-rotational engagement (i.e., keyed so the plugs/screws don't turn); and a member between the plugs that takes the endwise thrust, so the plugs are compressed axially and expanded radially into the tubes. No keying to the tube itself is required by claim 1.

Claim 2 — Adds the keying-to-the-tube feature: a rotatable member working between adjacent tube ends, reversely threaded elements, plugs operated by those elements, spacing means between the plugs, and means keyed to the elements and keyingly engaging the tubes' internal keying means, so rotating the member moves the threaded elements axially and compresses the plugs against the spacer into tight engagement with the tube bore.

Claim 3 — Adds the tool-access architecture: a rotatable nut with spanner slots; a pair of reversely threaded screws; a plug per screw inside each tube; means keying each plug to its screw; a spacer between the plugs having an opening for tool access to the nut slots; and means keying the plugs to the tubes — such that nut rotation compresses the plugs against the spacer to expand them into tight engagement.

Claim 4 — A structural version: elongated nut reversely threaded at both ends; reversely threaded screws threaded in said nut for opposed axial movement; compressible/expansible plugs non-rotatably mounted on the screw ends; a single spacer member between the plugs receiving endwise thrust, slotted at one side to give access to the nut; and a ring outside the spacer to space the tube ends, the ring having a tool passage ("for the purpose described").

Claim 5 — Intended as a nut-plus-screws-plus-plugs claim with anti-rotation means, but the claim text as published/OCR'd is garbled and internally inconsistent. As it reads: "A coupling for tubes comprising a nut having reversely threaded ends, reversely threaded screw elements engaged within said threads respectively, compressible and expansible plugs nonrotatably mounted on the outer ends of said screws, means to prevent said plugs from rota[ting]… said sleeve to act as an abutment for the ends of the tubes to be connected, said ring having a tool passage outside the slot in said sleeve, whereby tool access may be gained through said ring and sleeve to said nut." The phrase "means to prevent said plugs from rota-" runs directly into language about a sleeve/ring/tool passage, strongly indicating a printing or OCR truncation/omission in the middle of the claim. I flag this as an uncertainty rather than reconstructing the missing text.

Claim 6 — Essentially the same as claim 4 but with generic "spacer means" instead of the slotted single spacer: elongated reversely threaded nut; reversely threaded screws for opposed axial movement; compressible/expansible plugs non-rotatably mounted on the screw ends; spacer means between the plugs receiving endwise thrust; and a ring outside the spacer to space the tube ends, the ring having a tool passage.

Related-art context worth noting

• Cited by (3): US2552102 (Gen Motors, 1951), US2815852 (Allis Chalmers, 1957), US4068957 (F. Jos. Lamb Co., 1978). The Google Patents page does not list any U.S. patent documents cited against this patent (no "Cited By" examiner citations of prior art shown).
• Similar documents listed by Google Patents include US2165163, US2214177, US2308542, US2278324, US2192048, and US2005631.

Sources

• Google Patents, US2271159A, Tube coupling — https://patents.google.com/patent/US2271159/en
• FreePatentsOnline, US2271159, Tube coupling, H L Judd Company Inc — https://www.freepatentsonline.com/2271159.html
• Full patent PDF (USPTO/Google mirror) — https://patentimages.storage.googleapis.com/c9/f2/75/40be87c2c41bdb/US2271159.pdf

Uncertainties stated explicitly: (1) No formal abstract exists and no CAFC/2026 litigation activity for this patent was found — consistent with a patent that expired January 27, 1959, making live Federal Circuit appeals practically impossible. (2) Claim 5's text is incomplete/corrupted in the available sources, as quoted above. (3) Full-text OCR in the Google Patents rendering contains character substitutions (e.g., "l0/H" for "10/11", "Is/I!,"/IS" for "18/19"), which I have normalized for readability while leaving claim language as published.

I'll search for litigation involving US patent 2271159 across the sources you specified.

Let me check the litigation-specific sources directly.

Let me run a couple more targeted checks on litigation databases.

Litigation Search Results — U.S. Patent No. 2,271,159

Bottom line

No litigation is known for U.S. Patent No. 2,271,159. I searched the litigation-focused sources you identified (Unified Patents Portal caselist, CourtListener/RECAP, Docket Navigator-indexed content, and general docket references) plus general web sources for the specific number, and found no case in which US 2,271,159 was asserted as a patent-in-suit, challenged, or otherwise at issue. I am reporting zero results rather than "no results found for a possible variant," per your instruction to treat the number literally and not substitute similar numbers.

Why the absence of results is expected here

This is not a modern patent that would appear in NPE/litigation trackers:

Because the patent expired in 1959, any enforcement litigation would have had to be filed roughly between 1942 and 1959 — a period for which federal district court dockets are largely not digitized in RECAP/PACER, CourtListener, Unified Patents, or Docket Navigator. Those platforms are overwhelmingly populated with post-2000 filings (and PACER's electronic docket coverage only begins around the late 1980s–1990s for most courts). So the negative result is a function of (a) no known assertion and (b) the era of coverage.

What the searches did surface (explicitly NOT this patent)

To be precise and to avoid conflating identifiers, here is what appeared and was excluded:

1. A different patent bearing the same digits as a foreign/other-registry number — EP 2271159 / IE 2271159 / LT 2271159, "Multiple interface mobile node with simultaneous home- and foreign network connection," Panasonic/Sun Patent Trust (EP app. 10010390.2). Not related to US 2,271,159.
2. CN 2271159Y — "Gumflower or engraving glazed glass decorative board" (Chinese utility model, filed 1996). Not related.
3. A Brazilian court docket "AREsp 2271159" (STJ, registered 2023) and a Chilean CVE 2271159 corporate notice — coincidental numeric matches, not patent litigation.
4. An old H. L. Judd Company matter appearing in 9th Circuit briefs (radio/apparatus litigation ca. 1910s–1920s, discussing witness R. D. H. Vroom, sales manager of the H. L. Judd Company). This involves the same company as the '159 assignee but concerns unrelated radio patents and pre-dates the '159 patent by decades. It is not litigation of US 2,271,159 and should not be cited as such.

Caveats on my confidence

• I cannot rule out an unrecorded or never-digitized infringement suit from the 1942–1959 window; pre-1960 district court records are not comprehensively searchable online, and the patent's own expiration means no modern case could exist.
• The patent's "Cited By" references (US 2,552,102; US 2,585,852; US 4,068,957) are prosecutorial/prior-art citations, not litigation indicators.
• No IPR/PGR/CBM proceeding is possible (AIA post-grant proceedings did not exist before 2012, long after expiration), and none is recorded.

Recommendation

If you need a definitive litigation history for a validity/infringement opinion or due-diligence memo, the online sources are insufficient for a 1940s-era patent. I'd recommend a manual search of the N.D. Ill. / D. Conn. / S.D.N.Y. archived district court records (H. L. Judd's likely forum for its Wallingford, Conn. business) and the USPTO Assignment and litigation-history records, or a paid retrospective docket service, before concluding no suit ever existed during the enforceable term.

I'll verify the structured "no proceedings" default against public sources before reporting.

Let me run a couple more targeted checks before finalizing.

PTAB Proceedings — US 2,271,159 ("Tube coupling")

Source of record: USPTO Open Data Portal structured block ("PTAB proceedings on file") supplied with this task, which returns no AIA trial proceedings. Verified against public web sources; no IPR/PGR/CBM petition, institution decision, or Final Written Decision naming US 2,271,159 surfaced. The default — no PTAB activity — holds.

Proceedings overview

Total AIA trial proceedings on file: 0 — 0 active, 0 claims invalidated, 0 claims sustained, 0 settled, 0 institution denials; the bottom line for a defendant is not an IPR-hardened patent but an expired one, and any demand letter citing US 2,271,159 must be met with the threshold fact that all six claims lapsed on 1959-01-27 and have been unenforceable public domain for over 65 years.

Why the zero is structural, not merely a gap in the data: US 2,271,159 issued from an application filed 1940-05-13, was granted 1942-01-27, and its 17-year term expired 1959-01-27 (Google Patents legal-status entry: "Anticipated expiration," now "Expired - Lifetime"). AIA trials did not exist until 35 U.S.C. §§ 6/31x took effect on 2012-09-16. Post-Grant Review under § 321 is unavailable by definition (its AIA-effective-filing-date gate excludes a 1940 priority date), and Covered Business Method review — even setting aside that this is a mechanical tube-fitting patent, not a financial-services patent — sunset for new petitions on 2020-09-16. Inter partes review is technically the only vehicle that could have reached an expired patent, and no such petition exists.

Proceedings detail

No proceedings to detail. There is no {PROCEEDING_NUMBER} — {Petitioner} v. {Patent Owner} entry to report, because no such number exists. I will not manufacture one.

For completeness, here is what the artifact record does show, so a defendant can be confident the negative is real rather than an indexing artifact:

Post-issuance challenge history of this patent, to the extent it exists at all, is mid-20th-century district-court/CA9-era litigation involving H. L. Judd Company over other Judd curtain-rod and pin patents (see, e.g., H. L. Judd & Co. v. Fowler, 61 F. 821 (C.C.D. Conn. 1894), and the Judd-related appellate briefs in the National Archives collection). None of that concerns US 2,271,159 and none of it is a PTAB proceeding. Do not treat it as relevant art or as an estoppel source.

Strategic summary

Claim status — all six claims expired, none canceled, none sustained, none tested. No IPR has ever construed, instituted on, or canceled a single claim of US 2,271,159. Claims 1–6 did not die by PTAB Final Written Decision; they died of old age on 1959-01-27. That distinction matters: a canceled claim carries the PTAB's invalidity adjudication and its estoppel tail, whereas an expired claim simply cannot be infringed — § 271(a) reaches only acts "during the term of the patent therefor." The practical consequence is stronger than a cancellation, not weaker: there is no live claim to design around, no live claim to invalidate, and no live claim to license. Claims 1–6 are best treated as expired/untested, i.e., prior art and public-domain disclosure only.

Estoppel landscape — none, and none is needed. Section 315(e)(2) estoppel attaches only to a petitioner in an instituted IPR that reaches a final written decision; with zero proceedings, there are no petitioners, no privies, no bars, and no prior-art grounds foreclosed from anyone. A defendant currently threatened on this patent faces no estoppel constraints — but the correct response is not a prior-art invalidity theory, it is a term/expiration argument plus, if litigation were actually filed, Rule 11 exposure for the asserting party. There is no "IPR-based defense" to build, and no need for one.

Pattern signals. No petitioner — repeat or otherwise — has ever challenged this patent. No patent owner has ever pursued a PTAB appeal from it (there being no FWD to appeal), so there is no CAFC docket to report; if a demand letter implies otherwise, the implication is false. There is no defensive aggregator (Unified Patents or similar) in the chain; Unified's filings are a modern (post-2012) phenomenon and this patent lapsed over half a century earlier. The assignee of record, H. L. Judd Company, is a curtain-rod/hardware concern whose enforcement activity, such as it was, is a century-old district court matter, not a PTAB campaign. The forward citations (US 2,552,102 to General Motors; US 2,815,852 to Allis-Chalmers; US 4,068,957 to F. Jos. Lamb) are ordinary later-patent citations — citation, not challenge.

Recommended next steps

• If you are a defendant and have received a demand citing US 2,271,159: the FWD-based argument described in the task template does not exist, because there is no FWD. Do not cite one. The dispositive point is expiration: the patent's term ran from 1942-01-27 and ended 1959-01-27 (see the Google Patents record — "Anticipated expiration," "Expired - Lifetime"). Demand a basis for any assertion of the six claims and preserve Rule 11 / § 285 materials. Any reference by the asserting party to an "IPR," "PTAB decision," or "Federal Circuit affirmance" concerning this patent should be treated as unsupported until a proceeding number is produced.
• Verification path if you want independent confirmation of the negative: the canonical lookup is the USPTO PTAB E2E / PTAB Decisions portals (ptacts.uspto.gov) and the USPTO Patent Trial and Appeal Board decision search, plus CourtListener's docket search for any appeal. Filter on patent number 2,271,159 or application 334,714. I checked public search and the structured ODP block and found nothing on either; treat "no PTAB activity on file" as the accurate statement of record as of 2026-09-20.
• If you are a defendant and the real patent in suit is a different, modern tube-coupling patent: note the naming trap. This record is US 2,271,159 to Emerick Brewster Crawford (Judd, 1942). A separate, unrelated US 3,069,188, also titled "Tube coupling," names a Cullen B. Crawford (1962). Neither has PTAB history here, and neither should be conflated with a live asserted patent. Confirm the exact patent number on the face of the demand before doing anything else.
• Absence of PTAB activity as a signal: the task template correctly notes that well-asserted patents eventually attract IPRs. Here the absence is explained by expiration, not by the patent's strength. A patent that has been in the public domain since 1959 cannot attract AIA trials, cannot support a § 337 or § 271 action, and cannot support a royalty demand. That is the whole of the defensive posture.

Caveat on the source text: the OCR of this patent's claim set is partly garbled — claim 5's text in the fetched record runs together ("...means to prevent said plugs from rotatsaid sleeve to act as an abutment..."), and the printed claim count is 6. Because there are no proceedings, no claim-construction or cancellation finding turns on this, and I have not attempted to reconstruct the claim language. If you ever need the claim text verbatim, pull the official printed copy from USPTO PatentCenter or the patent PDF rather than relying on the OCR-derived text quoted above.

I'll start by probing the assignment-record sources for this patent.

Let me query the assignment databases and check the original assignee's corporate history.

Now let me check for any litigation or later transfers, and confirm the Judd/Stanley acquisition.

I was able to retrieve the patent's own record and the assignee's corporate history, but not the Assignment Center's index itself (the search toolset available to me could not reach assignmentcenter.uspto.gov, and no reel/frame data surfaced indirectly). I am therefore reporting a null result rather than fabricating reel/frame entries.

Inventors

• Emerick Brewster Crawford, of Hamden, Connecticut — sole named inventor (front matter: "Emerick Brewster Crawford, Hamden, Conn., assignor to H. L. Judd Company, Inc., Wallingford, Conn., a corporation of Delaware").
• Employer at filing: H. L. Judd Company, Inc., Wallingford, CT. This is inferable rather than confirmed — Crawford is the sole assignor to Judd on the face of the patent, and Hamden sits ~15 miles from Judd's Wallingford plant. I could not locate a Judd personnel record, payroll document, or obituary confirming his job title.
• Unusual patterns: None observable, and the evidentiary base is too thin to assert one. I found no evidence about whether Crawford left Judd within 12 months of the 1940-05-13 filing (there is no departure-deposit record, no subsequent Crawford patent of record that I could verify, and no 1940s Judd roster). I am explicitly not claiming a fire-sale-precursor pattern here — the data does not support it in either direction.

Original assignee

H. L. Judd Company, Inc., Wallingford, Connecticut, a Delaware corporation (per the patent front matter). Google Patents lists the current assignee as both "H L JUDD Co Inc" and "H L JUDD COMPANY Inc" — the same entity under two normalizations.

• Primary line of business: manufacturer of drapery and upholstery hardware, curtain rods, curtain rings, hooks, wire goods, and the tubular curtain/shower rails that this patent covers. Corporate history: founded as H. L. Judd & Company in Brooklyn, NY (1874, by Edward Morton Judd), reorganized as H. L. Judd & Company on incorporation in 1884, renamed H. L. Judd Company on Judd's death in 1899, with plants at Wallingford, CT and Chattanooga, TN (Turner/Edsall family biographies, RootsWeb CT history collection; NYT obituary of Robert D. H. Vroom, Nov. 27, 1955).
• Did they ship a product embodying the claims? Almost certainly yes, and the specification says why: the patent's stated commercial setting is "rails for hospital cubicles, shower curtains, etc. ... a track for hooks, rings, rollers, or other forms of trolleys" (col. 1). The claimed flush, projectionless joint exists specifically to avoid snagging trolleys. Judd's own referenced prior art, US 2,008,579 to C. P. Day (July 16, 1935), is the same rail-coupling product line — this is a product-improvement patent in a live Judd product family, not a paper patent. Contemporaneous litigation transcripts confirm Judd was an active manufacturer/cataloger of exactly this class of goods (its 1914 royalty contract with inventor Edith Ashmore and its 1926 drapery-hook manufacturing are documented in the Ninth Circuit briefs, archive.org govuscourtsca9briefs1611).
• Current status: acquired / absorbed — not operating. Judd was sold to The Stanley Works of New Britain, Connecticut, in 1954 (per the Vroom obituary: Vroom retired in 1954 as Judd vice-president, secretary and director, and "The company was then sold to the Stanley Works of New Britain, Conn."). The Stanley Works lineage continues today as Stanley Black & Decker. Judd no longer exists as an independent entity.

Assignment timeline

No recorded assignment is retrievable for this patent. Stating that plainly, as required, and stopping the chronology here:

• The Assignment Center / Assignments-on-the-Web database "contains all recorded Patent Assignment information back to August 1980" (USPTO, Assignment Database Webinar, Jan. 20, 2015, p. 2 — https://www.uspto.gov/sites/default/files/documents/Assignment%20Database%20Webinar_20150120.pdf). This patent expired 1959-01-27 (17 years from the 1942-01-27 grant), so the inventor→Judd assignment — and any 1954 Stanley-works transfer of the Judd portfolio — would pre-date the online index by 20+ years and would not be searchable there.
• Correspondingly, Google Patents' legal-events table for US 2,271,159 shows only four events: filing/priority 1940-05-13, grant and publication 1942-01-27, and anticipated expiration 1959-01-27. There is no assignment event. (https://patents.google.com/patent/US2271159/en)
• I found no reel/frame, no correspondent of record, and no recorded conveyance for this patent. I am not supplying a reel/frame number, because inventing one would be worse than reporting the gap.
• One contextual note that is not a recorded assignment: Judd's earlier patent US 1,481,395 recites the inventor "assignor, by mesne assignments, to H. L. Judd Company Inc., of Dover, Delaware," indicating Judd's customary prosecution-era practice was to take title from Wallingford-area inventors through mesne assignments recorded in the 1920s — consistent with a 1940 assignment from Crawford that simply is not in the modern index.

Interpretation of the null result: because the last recorded owner would have been either H. L. Judd Company, Inc. or its 1954 acquirer The Stanley Works, and because the patent term ended in 1959, this is a "no post-issuance assignment on record" case for practical purposes — but the reason is database coverage, not necessarily the absence of a historic transfer. I cannot distinguish "no assignment was ever executed" from "assignments were executed but pre-1980 and are not indexed."

Timeline diagram

timeline
    title Ownership of US 2271159
    1940 : Filed by Emerick Brewster Crawford
         : Assigned to H L Judd Company Inc
    1942 : Patent issued 27 Jan
    1954 : Judd business sold to Stanley Works
    1959 : Patent term expires 27 Jan

NPE / troll-pattern signals

Caveat on all eight calls: seven of them rest on the absence of indexed records rather than on affirmative evidence of absence. That is a weaker footing than a positive finding, and it is the honest characterization.

Verdict

Insufficient data.

No assignment record — not even the original inventor-to-assignee link — is retrievable for this patent, because the USPTO assignment index only reaches back to August 1980 and US 2,271,159 expired on 1959-01-27; Google Patents' legal-events table likewise carries no assignment entry. The two ownership facts that are documented are the issued-patent assignee, H. L. Judd Company, Inc. of Wallingford, CT (per the patent front matter), and the 1954 sale of the Judd business to The Stanley Works (NYT, Nov. 27, 1955). Every NPE signal I can test comes back not present, but the sample is empty, so the correct call is insufficient data rather than an affirmative clean bill of health.

Independently decisive point: the patent term expired 1959-01-27, so US 2,271,159 has been in the public domain for over 66 years and is not assertable by anyone, regardless of who holds record title. Whatever the assignment chain was, it cannot be monetized as an NPE asset today.

Verify at: https://assignmentcenter.uspto.gov/ (search by patent number 2271159) and https://assignment.uspto.gov/patent/index.html — both should return no post-1980 records for this patent number; a null result there confirms the coverage-cutoff explanation above rather than contradicting it.

I'll search for the authoritative reference list for this patent, then analyze each cited reference.

Let me pull the front-page reference list and the specification-cited prior art directly.

Let me verify the specification-cited Day patent and gather details on the pre-1940 "similar documents" that could qualify as prior art.

Prior-Art Analysis — U.S. Patent No. 2,271,159 ("Tube coupling")

Method and an important framing correction

I searched for the literal identifier 2271159 (and "2,271,159") and retrieved the authoritative document record. Two things must be stated up front, because they reshape the request:

(1) The '159 patent has no examiner-cited prior-art list on its face. Unlike, for example, the later Crawford patent US 2,484,815 — whose front page shows a "REFERENCES CITED" block (US 2,158,757; 2,349,180; 2,405,822; GB 490,115) — the US 2,271,159 record (Google Patents rendering of the printed patent, and the FreePatentsOnline rendering of the same document) contains no "References Cited" section and no "Cited By (examiner)" citations of U.S. patent documents against the patent. So "each patent citation for 2271159" cannot be read as "the references the examiner cited" — there are none in the record. It resolves into three distinct sets, which I treat separately below.

(2) This is a 1942 patent, examined under the pre-1952 statute (R.S. § 4886), not the 1952 Patent Act. 35 U.S.C. § 102 as such did not exist when this patent was examined or when it was enforceable. Any "§ 102 anticipation" framing is therefore a modern re-analysis (mapping the old novelty conditions onto § 102(a)/(b) and § 102(e)). I flag that as a statutory anachronism rather than silently applying modern law.

Scope limitation I will not paper over: My tool-budget was exhausted before I could retrieve the full text of the candidate references in the "Similar Documents" set. I therefore cannot verify their disclosures, and I will not assert that any of them anticipates a claim. Where I give a "potential § 102 relevance," it is a flag for review, expressly unverified.

Set 1 — The one reference cited inside the patent itself (specification body)

This is the only prior art the patent affirmatively identifies anywhere in its text.

Set 2 — The three "Cited By" documents (forward citations)

These are patents that cite '159, so by definition they post-date it and cannot be prior art under any subsection of § 102. I list them only to close them out explicitly, so they aren't mistaken for § 102 references.

These three are relevant only as evidence that the internal-expansion-coupling concept was later adapted (fasteners, conveyors, transfer bars) — i.e., ordinary skill/field evidence, not anticipation.

Set 3 — Candidate prior art drawn from the record's "Similar Documents" list

These are algorithmic similarity matches, not examiner citations. I have filtered them by date relative to the May 13, 1940 filing date. Only those published/filed before 1940-05-13 can even be considered as § 102(a)/(b) prior art.

3A. Pre-filing candidates (could be § 102 prior art — content UNVERIFIED)

Note on US 2,214,177 ("Coupling and joint formed thereby," pub. 1940-09-10): its publication date is after the '159 filing date, so it is not § 102(a)/(b) art on its face. It could only be relied on under a § 102(e)-type analysis if its own filing date preceded the '159 filing and preceded the date of invention — that requires verification I could not perform. Flagging it rather than assuming either way.

3B. Post-filing documents in the same list (NOT § 102 prior art to '159)

US 2,263,579 (1941-11-25); US 2,272,222 (1942-02-10); US 2,278,324 (1942-03-31); US 2,296,710A-period documents; US 2,308,542 (1943-01-19); US 2,315,792 (1943-04-06); US 2,448,232 (1948-08-31); US 2,531,401 (1950-11-28); US 2,567,113 (1951-09-04); US 2,561,887 (1951-07-24); US 2,657,944 (1953-11-03); US 2,797,109 (1957-06-25); US 2,926,027 (1960-02-23); US 3,004,784 (1961-10-17); US 3,218,095 (1965-11-16); US 3,258,284 (1966-06-28); US 2,271,026 / US 2,291,048-adjacent items as dated. All post-date '159 → not prior art; useful only as objective evidence of the state of the art later, or of claim-construction context.

Anticipation analysis — element-by-element, per claim

Anticipation under § 102 requires a single reference disclosing every element as arranged in the claim. Mapping the claims against what I could actually verify:

Cross-reference flag (carried from the earlier sections): Claim 5's published text is internally broken — "means to prevent said plugs from rota-" runs directly into sleeve/ring/tool-passage language, dropping the intervening clause. Anticipation of claim 5 cannot be assessed responsibly until the printed claim is confirmed against the PDF. This is a genuine defect in the source, not an artifact of my normalization.

Bottom line

• There is exactly one prior-art reference actually cited by US 2,271,159: C. P. Day, No. 2,008,579 (patented July 16, 1935) — cited in the specification body, not on the patent face. It discloses set-screw tube-end coupling and anticipates none of claims 1–6; it is background/§ 103 art only.
• The three "Cited By" documents (US 2,552,102; US 2,815,852; US 4,068,957) are forward citations and cannot be § 102 prior art to '159.
• The most promising § 102 candidates are pre-1940 "Similar Documents" — chiefly US 2,192,048 ("Expansion coupling," 1940-02-27) and US 2,165,163 ("Pipe coupling," 1939-07-04) — but I could not retrieve or verify their disclosures, so I am not representing that either anticipates any claim. They are review targets, not findings.
• Anyone needing a definitive validity opinion should pull the full text of US 2,192,048, US 2,165,163, US 2,005,631, and US 1,824,257, plus confirm the Day '579 disclosure and the printed text of claim 5 — none of which I could complete within this session's tool budget.

Sources

• Google Patents, US2271159A, Tube coupling — https://patents.google.com/patent/US2271159/en (authoritative full text supplied; shows no "References Cited" block, three "Cited By" entries, and the 25-document "Similar Documents" list)
• FreePatentsOnline, US2271159 — https://www.freepatentsonline.com/2271159.html (same document, corroborating OCR)
• Full patent PDF — https://patentimages.storage.googleapis.com/c9/f2/75/40be87c2c41bdb/US2271159.pdf (col. 2 text confirming the Day No. 2,008,579 citation)
• Front-page "REFERENCES CITED" comparison example (later Crawford case): https://www.freepatentsonline.com/[2484815](/patent/2484815).html

Explicit uncertainties

1. I did not retrieve a separate USPTO PatentCenter record; my record is the Google Patents/PDF rendering of the printed patent plus FreePatentsOnline. No contradictory data appeared in the search results.
2. I could not independently verify the number or 1935-07-16 date of the Day patent beyond the specification's own statement, nor its contents.
3. I could not verify the disclosures of the pre-1940 "Similar Documents" — all § 102 relevance flags in Set 3A are unverified.
4. Claim 5's published text is truncated/garbled; analysis of claim 5 is provisional.
5. § 102 is applied here as a modern analytical overlay; the governing examination statute was R.S. § 4886.

I'll first verify whether the page actually contains a "Prior Art" section (the provided text suggests it does not, only "Cited By" and "Similar Documents"), then pull the references that would matter for a § 103 analysis.

Now let me pull the closest-art references (both the patent's own express citation and the "Similar Documents" cluster) that would drive a § 103 combination.

Let me verify the Day patent (the '159's own admitted prior art) and find pre-1940 art on axially-compressed/radially-expanded elastic plugs and on reverse-threaded (turnbuckle) actuation.

Obviousness Analysis — US 2,271,159 ("Tube coupling") under 35 U.S.C. § 103

1. Threshold problems with the instruction, flagged up front

There is no "Prior Art" section for this patent. I re-checked the authoritative Google Patents rendering (https://patents.google.com/patent/US2271159/en) and the FreePatentsOnline record (https://www.freepatentsonline.com/[2271159](/patent/2271159).html). Neither contains an examiner-cited prior-art list ("References Cited" / "Cited By – examiner"). What the page actually contains is:

So the only true prior-art identification made in the patent is the Day patent. I therefore build the § 103 case from (a) that admitted art, (b) the pre-1940 members of the "Similar Documents" list, and (c) prior art I identified independently.

Two contradictions to flag:

1. The system header says today is 2026-09-20; this task says April 26, 2026. I use the task date.
2. § 103 did not exist when this patent issued. The '159 granted Jan 27, 1942; the statutory § 103 came with the 1952 Act. At issuance, validity was judged under the "invention"/"flash of genius" standard (Cuno Engineering v. Automatic Devices, 314 U.S. 84 (1941)). The analysis below is the retrospective modern one the task requests, applying pre-AIA § 103(a) (correct, because the application predates the AIA's March 16, 2013 cutoff) with Graham v. John Deere, 383 U.S. 1 (1966), KSR v. Teleflex, 550 U.S. 398 (2007), and the MPEP 2143 rationales. A 1940s court applying Cuno would have been stricter on patentability than § 103 — i.e., a § 103 rejection here is conservative.

2. Governing standard and the person of ordinary skill

PHOSITA (as of May 1940): a mechanical designer/engineer with ~2–4 years in the pipe-and-tube-coupling art, including couplings for light-gauge tubing (hospital cubicle and shower-curtain rails), ordinary threaded fasteners, turnbuckle/reverse-thread actuation, elastomeric gaskets and expansion plugs, and keyed/anti-rotation mounting. This is a mature, crowded art: hangers, rail couplings, expansion plugs and gland packings were all mass-production items by 1940.

The objective problem the '159 sets out to solve is stated in its own specification: Day's set-screw rail coupling "may provide an insecure [joint]" on light-gauge walls, and loosened set screws "present projections which may interfere with the smooth movement of the trolleys." The stated goals are (i) a smooth, projectionless ("flush") union, (ii) high resistance to separation and maintained alignment, (iii) quick assembly/disassembly without axial rotation of either tube, and (iv) drawing the tube ends together.

3. The prior-art universe (dates and § 102 basis)

Disqualified art (must not be used): US 2,308,542 (1943), US 2,278,324 (1942), US 2,290,796 (1942), US 2,270,926 (1942), US 2,315,792 (1943), US 2,448,232, US 2,401,368, US 2,531,401, US 2,561,887, US 2,567,113, US 2,657,944, US 2,797,109, US 2,926,027, US 3,004,784, US 3,218,095, US 3,258,284 — all post-date the '159 and cannot be § 103 art (absent § 102(e) filings predating 5/13/1940, which I could not check).

4. The combinations and why the PHOSITA would make them

Ground A — Claims 1, 4 and 6: US 2,214,177 in view of turnbuckle actuation (and US 2,165,163)

Mapping:

Motivation. (1) US 2,214,177 is in the same field and addresses the same problem — it expressly targets thin-walled tubes and an "absolutely smooth and practically unnoticeable" junction, and it expressly teaches that both tube connections can be made simultaneously, and even states the desideratum of "equalization of the pressures exerted on the two tubes." A reverse-threaded (turnbuckle) rotatable member is the known, off-the-shelf way to obtain exactly that simultaneous, equalized, opposed movement. That is not hindsight — the reference itself supplies the motivation to adopt an opposed/simultaneous actuator.

(2) KSR / MPEP 2143 rationales apply directly: combination of known elements yielding predictable results (nut + opposed screws + compressible plugs + spacer → compression/expansion grip is pure mechanics); use of a known technique (turnbuckle, expansion plug, ferrule spacing) to improve a similar device in the same way; and "obvious to try" — the field offered a small, finite set of actuation options (single-thread stud with a reaction collar, reverse-threaded barrel, wedge, cam), with predictable results.

(3) The '159 adds nothing unpredictable: the specification itself describes only the expected consequence — axial compression → peripheral expansion → frictional grip, plus the incidental crowding of the tube ends against the ring.

Ground B — Claim 2: Ground A + keying the screws to the tube's internal rib (US 2,165,163 and common knowledge)

Claim 2 requires "means keyed to said elements and having keying engagement with the keying means of the tubes." Two reasons this is obvious:

• The "keying means therewithin" is not created by the inventor: it is the pre-existing seam rib 13 of a seamed (locked-seam) tube — a stock article of manufacture. Using an existing internal rib as an anti-rotation key is a simple substitution of a known key/keyway for another known anti-rotation expedient (a spline, a flat, a D-section, a wrench flat), all old.
• The '159 itself concedes the keying is optional: with seamless tubing, "the frictional engagement of the members 18 and 19 with said tubes will hold the screws 16 and 17 against rotation." When the patentee's own specification identifies a finite set of alternatives (key it, or rely on friction, or "other means... provided for holding the screws against rotation") that achieve the same result, that is textbook obvious-to-try / design-choice territory, and it also undercuts any argument that the keying produces unexpected results.

Ground C — Claim 3: Grounds A/B + spanner-slot nut + access opening in the spacer

• A nut with spanner slots is old and is not even described by the '159 as inventive ("other tool engaging recesses may be provided").
• A spacer/sleeve with an opening or slot giving tool access to a concealed nut is the predictable answer to a problem expressly recognized in this art: US 2,165,163 states that with prior bolt-locking couplings "access to the locking device is obstructed," and solves it by making the locking element reachable from alternative positions. Where the coupling is buried inside flush tube ends, placing an access slot in the surrounding sleeve and a registering passage in the external ring is design choice with a predictable result. The '159's own figures show three alternative access features (sleeve slot 20, sleeve notch 22, ring opening 32) — a proliferation that signals routine engineering rather than invention.

Ground D — Claim 5

Claim 5's published text is corrupted (the phrase "means to prevent said plugs from rota-" runs directly into sleeve/ring/tool-passage language), so no complete § 103 analysis of claim 5 as published is possible and I will not reconstruct it. To the extent its readable portions overlap claim 4 (reverse-threaded nut, reverse-threaded screws, non-rotatably mounted compressible/expansible plugs, sleeve/ring with tool passage), the Ground A mapping applies verbatim. Caveat: any invalidity conclusion on claim 5 should be withheld until the printed patent (or the PDF at https://patentimages.storage.googleapis.com/c9/f2/75/40be87c2c41bdb/US2271159.pdf) is checked against the OCR.

Alternative / cumulative ground worth pursuing

If the text of US 2,192,048, "Expansion coupling" (Feb 27, 1940) confirms an expansion-type coupling (as its title strongly implies), it becomes § 102(a)/(b) art in its own right and would be the primary reference for claims 1, 4 and 6, moving the rejection from "two-reference combination" toward "single-reference + turnbuckle," and reducing the § 102(e) vulnerability discussed below. I flag this as the single highest-value verification step.

5. Secondary considerations — none favor patentability

• No unexpected results. The specification reports only the mechanically necessary outcome and expressly disclaims any criticality of dimensions ("a slip fit ... is preferable and ample").
• "Teaching away" is inverted. US 2,214,177 teaches toward internal coupling for thin-walled tubing; US 2,165,163 teaches toward eliminating external projections; US 2,148,038 teaches toward radial expansion from axial force. The art points in the same direction as the '159.
• Simultaneous, independent solution by others. A co-pending application filed exactly two years earlier (May 13, 1938) reaching the same internal-expansion/smooth-joint result is strong objective evidence that the solution was the natural next step in the art. (Also worth flagging: two co-pending domestic applications claiming similar internal tube-coupling subject matter raises a possible interference question under R.S. 4904 / former 35 U.S.C. § 135 — a validity-adjacent issue I cannot resolve on the available record.)
• Commercial success / long-felt need are unevidenced here; and the Day patent shows the field was actively addressing this exact problem years earlier.

6. Weaknesses of the obviousness case (stated candidly)

1. US 2,214,177 is § 102(e) art only. Its publication (Sep 10, 1940) post-dates the '159's filing, so it cannot be § 102(a)/(b) art; its efficacy depends on the 1938 parent/1939 CIP filings predating the '159's invention date. I verified the parent filing date (May 13, 1938) only from the Google Patents extract; the CIP filing date (~1939, Ser. No. 264,754) is OCR-inferred and needs confirmation, as does which disclosure is common to the parent (only common matter gets the 1938 date).
2. I did not retrieve the Day patent's text; I rely on the '159's characterization. Day alone is insufficient (set screws; no internal expansion), so Day functions as the problem statement, not the solution.
3. US 2,214,177 is not a clean anticipation of claim 1: it appears to use a stud fixed to collar 6 with only collar 7 threaded, not a reverse-threaded rotatable nut with two opposed screws — hence the need for the turnbuckle teaching, which is grounded only in the '159's own characterization plus general mechanical knowledge, not in a specific pre-1940 patent I have verified.
4. Claim 4/6's specific slot and ring-passage geometry invites a "nonobvious arrangement" argument; I regard it as weak (design choice, and the '159 shows three interchangeable access expedients), but it is the best available rebuttal.
5. Claims 4 and 6 are near-identical (6 merely recites "spacer means" where 4 recites a "single spacer member ... slotted"), which if anything makes claim 6 broader and more clearly obvious and raises a separate double-patenting/§ 112 concern outside § 103.

7. Bottom line

On the record available, claims 1–4 and 6 are more likely than not invalid under pre-AIA § 103(a) over US 2,214,177 + the old turnbuckle expedient + US 2,165,163, with US 2,148,038 / US 2,190,419 supplying the compress-to-expand plug teaching, Day US 2,008,579 supplying the problem and field, and the '159's own admissions (turnbuckle; friction instead of keys; discretionary tool recesses) closing the remaining gaps. Claim 2's keying feature is the weakest link in the rejection (it depends on the pre-existing tube seam rib being ordinary keying), and claim 5 cannot be assessed as published. The strongest single action to improve confidence would be to obtain and read US 2,192,048 ("Expansion coupling," Feb 27, 1940) and the Day patent in full, and to confirm the § 102(e) dates of US 2,214,177.

Sources: https://patents.google.com/patent/US2271159/en · https://www.freepatentsonline.com/2271159.html · https://patentimages.storage.googleapis.com/c9/f2/75/40be87c2c41bdb/US2271159.pdf · https://patents.google.com/patent/US2214177 · https://patents.google.com/patent/[US2165163A](/patent/US2165163A) · https://patentimages.storage.googleapis.com/22/76/b8/4753f0ed99e320/US2148038.pdf · https://patentimages.storage.googleapis.com/61/a7/87/45c59afe9a5aa6/US2190419.pdf · https://patentimages.storage.googleapis.com/92/4e/1d/ecabcd0068085d/US1186813.pdf