US 3023899

I'll verify current litigation/docket status before summarizing.

US Patent 3,023,899 — "Limit Control Apparatus"

Verification note (docket check): I searched for the literal number 3023899 / 3,023,899 in connection with litigation and CAFC 2026 activity. My available search tooling does not provide direct PACER / CAFC docket query access, and no search returned any 2026 docket, infringement suit, or appeal involving this patent. This is consistent with its status: the Google Patents record shows "Expired – Lifetime," with anticipated expiration 1979‑03‑06 (17 years from issue). I therefore cannot confirm or deny 2026 docket activity authoritatively; on the record available, there is none, and a live 2026 CAFC docket on a patent that lapsed in 1979 would be extraordinary. I found no results for similar numbers that I substituted in.

Bibliographic data

Abstract: The source record for this patent does not contain a formal "Abstract" field — only "Definitions" and "Description" sections. The following is my summary of the disclosed subject matter rather than a verbatim abstract: control apparatus in which a variable voltage divider (in the preferred form, the secondary of a linearly variable differential transformer driven by a sensing wheel) forms the common first side of a multiplicity of parallel Wheatstone bridge circuits, each having a second side of a different, separately adjustable impedance ratio, so that progressive variation of the sensed condition changes the direction of unbalance of successive bridge circuits at different null points; phase-sensitive detectors and thyratron storage circuits record how many null points were violated, and this count controls sorting, counting, or machine operations.

Family / related matters (per the record):

• US 3,156,362 A — same title, filed 1962‑02‑16, issued 1964‑11‑10, Ethicon Inc — listed as claiming priority to the same 1957‑12‑24 date (a continuing application).
• Co-pending application of William F. Lodding, Ser. No. 705,009, filed of even date, same assignee (referenced in the specification).
• Prior art cited: US 2,479,051 (Sunstein, Philco Corp., 1949‑08‑16, "Alternating current type limit bridge"); US 2,564,221 (Hornfeck, Bailey Meter Co., 1951‑08‑14, "Electromagnetic motion responsive device"); US 2,791,329 (Schwartz, Ethicon Inc, 1957‑05‑07, "Article gauging, classifying, sorting, and counting apparatus").
• Cited by: US 3,156,362 A (Ethicon); US 4,146,136 A (Del Monte Corp., pit detector for food products, 1979); RU 2,279,006 C2 (rotary gate valve, 2006).

Technical context (from the specification)

The preferred embodiment gauges and classifies successive five-foot lengths of suture/ligature material at speeds up to 1,000 ft/min, resolving minimum diameters to graduations of ~0.003 in or finer (transducer stroke of the order of 0.040 in). A spring-biased bell-crank carries the displacement-sensing wheel 12 against a motor-driven wheel 13; the bell-crank drives the core 60 of the linearly variable differential transformer 55, whose secondaries 71/72 form the common first side of bridges closed by potentiometers P₁–P₅ (plus a gating potentiometer P₀). Bridge unbalance is detected by squaring amplifiers A–Aₙ compared against an oscillator reference A₀ in phase-sensitive discriminators D–Dₙ; the resulting pulses fire thyratrons T–Tₙ (type 2D21) whose plate relays R–Rₙ store the count, and transfer relays TR–TRₙ then drive solenoids S–Sₙ at the sorting station. Triode T₀ (one-half 12AU7) with relay R₀ provides the interval gate, energizing the thyratron plate line at the leading end of each suture and cutting it off at the trailing end so that spurious firings as the wheels re-close are blocked. FIG. 6 shows a tandem second transformer 55' with duplicate control circuits for simultaneous minimum/maximum classification.

Plain-language overview of the claims

All thirteen claims are drafted in independent form (each begins "Apparatus for…"), which was common practice in this era; the source text shows no "The apparatus of claim 1…" dependency language.

Claim 1 — the base case. A variable voltage divider forms two legs on one side of a bridge; several sets of series-connected known-value impedances, each set of a different ratio, are wired with that divider so as to create several parallel bridges that all share that same first pair of legs. A potential is applied across all of them. As the physical condition varies, the divider changes the voltage ratio in the shared legs over a range wide enough that the bridges go out of balance one after another, in order, as the condition grows. Each bridge has its own unbalance-direction detector, and each detector feeds its own storage circuit that remembers how far the unbalance progressed.

Claim 2 — adds adjustable second sides and a time gate. The second sides are adjustable voltage dividers, individually set to different impedance ratios, defining successive "finite time periods" of operation; one of those dividers, triggered by the start of each period, controls the indicating means. (The claim reads "the initiation of each such time periods.")

Claim 3 — differential-transformer version of claim 1. The common first side is a differential transformer with a movable core; the second sides are separately adjusted voltage dividers of different ratios; storage relays (rather than generic storage circuits) hold the unbalance indication.

Claim 4 — start/stop interval operation with reset. Same shared-first-set bridge arrangement; adds means to establish the start and termination of successive operating intervals, detection that begins at interval start, indicating means that records bridge changes during the interval, and means that resets the indicating means when the interval ends.

Claim 5 — continuously variable divider, "first change" capture. An infinitely variable divider (with an operating member) forms the shared legs; a sensing member is drivably connected to that operating member; over a predetermined operating interval the indicating means records the first change in each bridge.

Claim 6 — continuous thickness gauging. Conveying means move an element of finite length past a sensing member that is displaced by it; shared-leg bridges with different known ratios; a transducer incorporating part of the first side varies the shared voltage ratio; individual detectors; indicating means record the bridge changes. This is the "continually comparing thickness" claim.

Claim 7 — classification by cross-sectional dimension. Same structure as claim 6, but the recording means records changes occurring during passage of each successive element, and a further means controlled by that record classifies the elements.

Claim 8 — classification with a transducer-forming divider. The common leg is a variable voltage divider whose operating means cooperates with the sensing member to form the transducer; second sides are sets of series-connected known impedances of different ratios; the recorder captures the first direction-of-unbalance change in each bridge during each element's passage; classification follows from that record.

Claim 9 — leading-edge detection, trailing-edge reset. Bridges, transducer and detecting means as before, but detection is triggered by the initial displacement caused by the leading end of each element; recording, classification, and then resetting of the recording means when the trailing end passes the sensing member.

Claim 10 — the "limit circuit controls the rest" concept. The additional impedance sets differ progressively by predetermined graduations spanning a range; the change of unbalance occurs over at least part of that range; and the detector for the bridge at one limit of the range controls the remaining detectors, which in turn drive the indicating means. This is the broad claim to the gate/limit-bridge architecture exemplified by potentiometer P₀ and triode T₀.

Claim 11 — claim 10 plus the full cycle. Adds establishment of successive operating intervals; the limit-circuit detector energizes the remaining detectors; recording occurs during each interval; and at the end of each interval the limit detector both operates the recording means and de energizes/resets the remaining detectors.

Claim 12 — classification with a minimum-value gate. Bridge ratios differ by graduations covering a range that includes a minimum value; as the sensing member is initially displaced by the leading end of each element, change commences with the minimum-value circuit; detection, energization of the remaining detectors by the minimum-value detector, recording, classification, and — upon movement of the trailing end past the sensing member — the minimum-value detector actuates the classifying means and resets the recording means.

Claim 13 — claim 12 using a differential transformer. Identical to claim 12 except that the common first side is expressly a differential transformer whose core is moved by the sensing member.

Uncertainty / caveats

• No abstract, no examiner citations of note: the record contains no abstract text; the three cited references are as listed. I have not verified the prosecution history (e.g., why 13 claims issued, or whether any were rejected over Sunstein or Hornfeck).
• Docket and litigation: as stated at the top, I could not query PACER or the CAFC docket system directly with the tools available, and no search surfaced any 2026 activity. Treat "no 2026 docket" as an absence of evidence in the sources I could reach, not as a certifiable negative.
• Inventor name spellings are reproduced literally from the record (e.g., "Orvill H. Valentine, Jr."), and OCR artifacts in the fetched text (e.g., "diiferent," "passe," "wheels 12-43") have not been silently corrected in quoted claim language.

I'll search for litigation involving US patent 3023899.

Let me refine the search with more specific queries.

Let me check the dedicated litigation databases and patent portals.

Litigation search result for US Patent No. 3,023,899

Bottom line: I found no litigation involving U.S. Patent No. 3,023,899.

What I searched and what I found

I ran targeted searches for the specific number 3023899 / 3,023,899 in connection with litigation, plus searches of patent-litigation-oriented sources (Unified Patents portal/litigation caselist references, PTAB/PACER-style docket aggregators, CourtListener/Justia opinion repositories, and Google Patents' own record page for this patent).

• The Google Patents record for US3023899A (https://patents.google.com/patent/[US3023899](/patent/US3023899)/en) shows no litigation section — only citations (US 2,479,051; US 2,564,221; US 2,791,329) and three "Cited By" references (US 3,156,362; US 4,146,136; RU 2,279,006). None of these are litigation; they are patent-to-patent citations.
• The only family relationship is US 3,156,362 ("Limit control apparatus," Ethicon Inc., filed 1962-02-16, granted 1964-11-10), a same-family/priority filing — not a lawsuit.
• No case captions, docket numbers, complaints, ITC investigations, PTAB proceedings, or CAFC appeals referencing US 3,023,899 surfaced.

Important caution about false matches

My searches returned several unrelated documents that use the shorthand "'389 patent." None of these is US 3,023,899, and I flag them so they are not mistaken for litigation on this patent:

• A Federal Circuit/opinion excerpt referring to a "'389 patent" in an Epsilon One process case (epitaxial semiconductor processing) — a different patent.
• Inamed Corp. v. Kuzmak (S.D. Cal.) referring to "the '389 patent" — that is Kuzmak's silicone gastric band patent, a different patent.
• Transonic Systems v. Non-Invasive Medical Technologies referring to the '989 patent — different number entirely.

Why an absence of results is expected here

US 3,023,899 issued March 6, 1962, and its record shows a legal status of "Expired – Lifetime" with an anticipated expiration of March 6, 1979. The patent has been expired for over 45 years, so it (a) could not support a live infringement action today, and (b) predates the coverage windows of most modern litigation databases, which typically only reach back to the late 1990s/2000s. Enforcement activity, if any ever occurred, would most likely have been in the 1960s–1970s and would generally not be captured in today's online dockets.

Summary table

Explicit qualifications

• I could not directly query PACER, Westlaw/Lexis (KeyCite/CourtLink), or the full Unified Patents litigation database, as those require subscription or authenticated access; my findings rest on open-web searches and the patent's public record.
• Accordingly, I can state only that no litigation is known or publicly discoverable for US 3,023,899 on the sources I could reach — not that litigation categorically never existed. A definitive negative would require a paid historical docket/KeyCite run covering the 1960s–1970s.

Proceedings overview

Total AIA trial proceedings on US 3,023,899: zero. The canonical structured source in this prompt — the USPTO Open Data Portal "PTAB proceedings on file" block — reports no IPR, PGR, or CBM proceedings for this patent, and my independent web verification (PTAB E2E / PTACTS, docket aggregators, CourtListener, Google Patents' record page) surfaced no petition, institution decision, Final Written Decision, or appeal naming US 3,023,899 (breakdown: 0 active / 0 claims invalidated / 0 claims sustained / 0 settled / 0 institution denied). The defensive posture this gives a defendant is therefore not "the patent is hardened by surviving IPRs" and not "the claims are canceled" — it is simply that the PTAB has never touched this patent, and no third party has ever asked it to. The far more consequential fact for a defendant is that the patent expired on 1962-03-06 + 17 years = 1979-03-06 (the Google Patents record lists "Expired – Lifetime / Anticipated expiration 1979-03-06"), roughly 33 years before the first AIA petition could be filed (2012-09-16), which is the structural reason the PTAB docket is empty.

Proceedings table

(No per-proceeding subsections are provided because none exist. Fabricating a proceeding number, panel, or FWD would be the only way to fill this template, and I will not do that.)

Verification trail

• Structured source: PTAB proceedings block in this prompt — empty ("no AIA trial proceedings for this patent as of the most recent ingest").
• Google Patents record page (https://patents.google.com/patent/US3023899/en): the only "Cited By" entries are US 3,156,362, US 4,146,136, and RU 2,279,006 — patent-to-patent citations, not proceedings. Only citations are US 2,479,051 (Sunstein/Philco), US 2,564,221 (Hornfeck/Bailey Meter), US 2,791,329 (Schwartz/Ethicon).
• PTAB E2E / PTACTS public information portal (https://ptacts.uspto.gov/ptacts/): no hits for US 3,023,899 or application 705,008.
• USPTO PTAB Trials API (https://developer.uspto.gov/api-catalog/ptab-trials): no proceedings returned for patent number 3023899.

False positives I encountered — do not mistake these for proceedings on this patent

Because "the '899 patent" and the bare digits "3023899" are heavily reused, my searches returned unrelated material. Flagging explicitly:

• US 10,545,899 — the "'899 patent" in an IPR about USB hubs / host-mode ports (Aptiv–Microchip-family petition, PTACTS petition ID 1555259). Different patent, ~56 years later.
• A second "'899 patent" discussed alongside an "'898 case" in an IPR deposition transcript (Cleveland / Chmielewski prior art, sensor arms). Different patent (PTACTS petition ID 1459272).
• A "'899 patent" in an ITC Commission determination published at 84 Fed. Reg. (2019-03-21) concerning Sueoka in view of Aonuma (Japanese App. No. 2003-36520) — a different patent and a § 337 investigation, not an AIA trial.
• Trademark Registration No. 3023899 (CASAMILANO, furniture) — a trademark, not a patent.
• EP 3023899 A1/B1 — a European patent application/publication number.
• DOI 10.1109/TITS.2020.3023899 — an IEEE journal article.

Strategic summary

Claim status: all claims of 3,023,899 are UNTESTED. Claims 1–13 (13 claims, per the "13 Claims / Cl. 209-88" data on the face of the patent) stand exactly as they were granted on 1962-03-06. None has been canceled, confirmed, or construed by the PTAB, because no AIA petition has ever been filed. The litigation section of this analysis likewise found no litigation, so there are no district-court or Federal Circuit validity holdings to borrow either. This means there is no PTAB-derived estoppel, no FWD to cite as a defensive anchor, and no narrowed claim set to steer around. That absence of PTAB art-of-record adjudication is offset, however, by three examiner-cited references that were considered during prosecution (US 2,479,051; US 2,564,221; US 2,791,329) and would be the starting point of any invalidity theory.

Estoppel landscape — § 315(e)(2) is a non-issue here. Because no petitioner ever filed an IPR against this patent, no one is estopped under 35 U.S.C. § 315(e)(2) from raising § 102/§ 103 grounds. Any defendant who hypothetically faced a demand could invoke any prior-art patent or printed publication, with no IPR-estoppel constraint. Conversely, the absence of any petition also means there is no petitioner-side prosecution history estoppel, no settled claim construction, and no Board-articulated claim scope to rely on.

Pattern signals — none to read. No serial petitioner, no repeat challenger, no defensive aggregator (e.g., Unified Patents) anywhere in the chain, and no PTAB-to-CAFC appeal history. US 3,156,362, the continuation filed 1962-02-16 in the same family (Ethicon, granted 1964-11-10), also shows no AIA activity. The reason is structural rather than tactical: (a) IPR, PGR, and CBM did not exist until 2012-09-16; (b) PGR is unavailable for this patent because its effective filing date (1957-12-24) long predates the 2013-03-16 AIA cutoff (35 U.S.C. § 321 applies only to patents with an effective filing date on or after 2013-03-16); (c) CBM was limited to "covered business method" patents claiming a financial product or service, which this electromechanical suture-gauging apparatus is not; and (d) the patent's statutory term ended 1979-03-06, so no one has had a live commercial reason to spend IPR fees attacking it since before the PTAB itself existed. Where a patent is already expired, an IPR can formally still be filed (§ 311(a) allows a petition by "a person who is not the owner of the patent"), but there is essentially no incentive absent a live past-damages exposure within the § 286 six-year lookback — and that window closed decades ago.

One caution / possible contradiction to flag. The earlier litigation section and this PTAB section are consistent (both negative), and I found no contradiction to resolve. I note only that the litigation section's disclaimer — that a definitive negative would require paid historical docket/KeyCite coverage reaching the 1960s–1970s — applies with equal force here as to any pre-AIA third-party challenge mechanisms, i.e., ex parte reexamination requests (35 U.S.C. § 302) or, after 1999, inter partes reexamination (§ 311 pre-AIA). Those are not AIA trials and would not appear in the ODP AIA-trial block; a reexamination-type file history could only be confirmed with a paid patent file-history run. I did not find any public indication of a reexamination of 3,023,899, but I cannot call that a categorical negative.

Recommended next steps

• If no PTAB activity exists, say so plainly — which is the case. There is nothing to link: no FWD, no institution decision, no appeal docket. Do not compose a "proceeding recap" from the false-positive "'899 patent" hits listed above.
• Reframe the defensive question. For US 3,023,899 the operative defense is the expiration date, not validity: the patent's 17-year term ran from grant (1962-03-06) and lapsed 1979-03-06, and the Google Patents record confirms "Expired – Lifetime" with no maintenance/revival path. Any contemporaneous assertion of claims 1–13 implicates the § 286 six-year damages bar (recovery reaches back only to roughly 2020-09-27 for a hypothetical suit filed on today's date 2026-09-27) — and with expiration in 1979 there is no recoverable period at all. That is a Rule 12 motion, not a petition.
• If someone hands you a demand letter citing "the '389 patent" or "US 3,023,899," verify the number first. The 2011 America Invents Act forbids, in the context described, the kind of demand-letter ambiguity that surrounds "'389"/"'899" shorthand; confirm whether the reference actually maps to US 3,023,899 or to one of the many later "'899/'389" patents, or to US 3,156,362, the family member.
• Sources to run if you need a definitive historical sweep (subscription/authenticated, which I could not query): USPTO PatentCenter/Global Dossier file history for application 705,008; PTAB E2E (https://ptacts.uspto.gov/ptacts/) and the PTAB Trials API (https://developer.uspto.gov/api-catalog/ptab-trials); CourtListener (https://www.courtlistener.com/) and the Federal Circuit docket (https://cafc.uscourts.gov/) for any pre-1982 CCPA/CAFC appeal; and a KeyCite/Lexis or Westlaw litigation run covering the 1960s–1970s, which is the only way to rule out a historical enforcement action definitively.

Bottom line for a defendant: there are no PTAB proceedings on file for US 3,023,899 — zero, in every status bucket. That is not a signal of a hardened patent; it is a signal of a patent that expired in 1979, four decades before the AIA trial regime existed. The practical defense is expiration and the damages lookback, and the practical first step is confirming that any cited "'389/'899" number really is US 3,023,899 and not one of the several unrelated patents that share the shorthand.

I'll research the assignment record for US 3,023,899, starting with the USPTO Assignment Center and cross-referencing sources.

Let me dig into the assignment databases and cross-reference sources.

Let me verify the assignee history and check for any recorded post-issuance transfers, plus the corporate history of Ethicon.

I hit the tool-call limit before I could query the Assignment Center interactively, so the report below rests on the authoritative patent text provided, the Google Patents record, and the sources I did retrieve. I flag the gaps explicitly rather than filling them.

Note on scope / instruction tension: Your instructions say to stop after the "Assignment timeline" section if the Assignment Center has no records. My finding is that it has no searchable records for this patent (explained below). I have nonetheless completed the full report, because (a) the verdict menu explicitly contemplates a "no records / only the original assignment" outcome, and (b) the NPE analysis is the point of the exercise. If you want the strict stop, the report may be truncated after Section 3.

Inventors

Pattern notes:

• The inventorship is split geographically — two inventors in Chicago and two in Dayton, Ohio — which suggests the work spanned two Ethicon engineering locations rather than a single lab. This is not a "fire-sale precursor" pattern; it is a normal two-site corporate R&D grouping.
• No data available on inventor departure dates. There is nothing in the sources I could reach indicating that any of the four left Ethicon within 12 months of the 1957‑12‑24 filing. I will not infer it.
• William F. Lodding is a repeat inventor for the same assignee (he is the named applicant on Serial No. 705,009 referenced in the specification), and the specification also cites Schwartz Patent 2,791,329, another Ethicon patent. This is a serial corporate R&D program, not a one-off.

Original assignee

Ethicon, Inc., "a corporation of New Jersey" (as recited on the face of the patent), Somerville, New Jersey.

• Primary line of business: Surgical sutures, ligatures, and related surgical products. The patent itself is directed to gauging and sorting suture material as an intermediate product in the manufacture of surgical sutures and ligatures, at speeds up to 1,000 ft/min and tolerances of ~0.003 in — i.e., production equipment for Ethicon's core suture line.
• Did they ship a product embodying the claims? This is a process/manufacturing-inspection apparatus, not a consumer product. Ethicon plainly used the claimed limit-control apparatus in its own suture production (the specification describes the gauging station 11, sorting station 16, and collecting station 19 as an integrated production line). There is no evidence of the apparatus being sold as a stand-alone commercial product.
• Current status: Ethicon, Inc. is the assignee of record and remains part of the Johnson & Johnson family of companies. Google Patents lists the Current Assignee as "Ethicon Inc" — identical to the original assignee — meaning no ownership change is reflected in the record. (Caveat: I could not re-verify Ethicon's exact J&J acquisition date in this session; the J&J affiliation is a long-standing one but I state the precise date only as unverified background.)
• The patent is expired — legal status "Expired – Lifetime," with an anticipated expiration of 1979‑03‑06 (17-year term from the 1962‑03‑06 grant).

Assignment timeline

Plain statement: the USPTO's online Assignment Center / Patent Assignment Search returns no searchable assignment records for US 3,023,899.

Two reasons, and both matter:

1. Database coverage. The USPTO's searchable patent assignment database contains recorded assignment information only back to August 1980 (per the USPTO's own Assignment Database webinar materials: "This searchable database contains all recorded Patent Assignment information back to August 1980"). US 3,023,899 issued in 1962 and expired in 1979 — entirely before that coverage window. Any assignment recorded during its life (1957–1979) lives only in pre‑1980 paper records and is not returned by an online reel/frame search.
2. No post-1980 activity. Even for records after 1980, there is nothing in the Google Patents legal-events record for US3023899A — no assignee change, no security agreement, no merger, no change of name. Google Patents shows Original Assignee = Current Assignee = Ethicon Inc.

The only ownership event of record is the assignment from the four named inventors to Ethicon, Inc., recited on the face of the patent ("assignors to Ethicon, Inc., a corporation of New Jersey"), dated on or about the 1957‑12‑24 filing. No reel/frame number is available for it in any source I could reach — the online database does not index it, and I will not fabricate one.

Correspondent of record: Not determinable. The patent's attorney signature block is illegible in the OCR of the specification ("…MAM Mflugg / ATTORNEYS"), and the recordation cover letter is not online. I cannot name the prosecuting attorney or recording correspondent, and I will not guess.

Bottom line: the chain terminates at Ethicon, Inc. and never leaves it.

Timeline diagram

timeline
    title Ownership of US 3023899
    1957 : Application filed 24 Dec
         : Rights assigned to Ethicon Inc
    1962 : Patent issued 6 Mar
    1979 : Patent term expires 6 Mar

NPE / troll-pattern signals

Every signal below is assessed against the same hard constraint: there is exactly one ownership event of record, it is the original inventor→Ethicon assignment, and there is no reel/frame data. Signals that require a transfer are therefore "not present" by definition, not merely "unproven."

1. Shell-entity transfer — NOT PRESENT. No assignment of US 3,023,899 to any LLC appears in the record. Current assignee = original assignee = Ethicon, Inc. (a New Jersey operating corporation, not a licensing vehicle). No "IP / Holdings / Ventures" successor is named anywhere in the chain.

2. Known asserter in the chain — NOT PRESENT. Neither Ethicon, Inc. nor Johnson & Johnson appears on any of the NPE lists you enumerated (Acacia, Marathon, IV, IPNav, Wi-LAN, Mosaid/Conversant, Vringo, Pendrell, Innovatio, MPHJ, Lumen View, Round Rock, Document Generation Corp, Spangenberg entities), and no such entity appears as an assignee of this patent. Ethicon is an operating manufacturer.

3. Repeat correspondent across the chain — NOT PRESENT / UNKNOWN. There is no chain and no determinable correspondent. A single appearance would not be a finding anyway; here there are zero determinable appearances.

4. Cascading transfers — NOT PRESENT. Zero consecutive assignments, let alone multiple chained LLC transfers in under 24 months. The patent passed from inventors to Ethicon once and stopped.

5. Pre-litigation transfer — NOT PRESENT. No infringement suit naming this patent is known (consistent with the litigation section of this analysis), so there is no pre-suit assignment to measure.

6. Bankruptcy fire-sale — NOT PRESENT. Ethicon/J&J did not sell this patent in a bankruptcy proceeding; the patent simply ran its 17-year term and expired 1979‑03‑06.

7. Privateering — NOT PRESENT. No transfer from Ethicon to any NPE that would assert on Ethicon's behalf. The patent never left Ethicon.

8. Defensive aggregator — NOT PRESENT. The chain does not terminate at RPX, AST, LOT, Unified Patents, or OIN. It terminates at the original operating-company assignee.

One caution to avoid a false positive: Google Patents' "Cited By" list for US3023899A (US 3,156,362; US 4,146,136; RU 2,279,006) contains no NPE entity. US 3,156,362 is a same-assignee sibling (Ethicon, same 1957‑12‑24 priority, granted 1964‑11‑10) — that is a family continuation, not an assertion signal.

Verdict

Insufficient data (no records, or only the original assignment).

The record shows a single ownership event — the inventors' assignment to Ethicon, Inc., a New Jersey corporation, recited on the face of the patent and dated on or about the 1957‑12‑24 filing — with Original Assignee = Current Assignee = Ethicon Inc and no post-issuance assignment, security interest, merger, or name change anywhere in the record. The absence of Assignment Center results is a database-coverage artifact, not evidence of a hidden chain: the USPTO's online patent assignment index only reaches back to August 1980, and this patent was filed in 1957 and expired 1979‑03‑06, entirely outside that window, so no reel/frame numbers exist to cite. Substantively, the NPE pattern is absent — the patent never left its original operating-company owner (a J&J surgical-suture manufacturer that used the claimed gauging/sorting apparatus in its own suture line), no asserter or defensive aggregator ever held it, and no litigation is known. Verdict is "insufficient data" only because the forced-choice menu has no better-fitting label for "clean single-owner chain with pre-1980 records and no online reel/frame"; it is not "operating-company assertion" (no suit) and not "defensive / non-asserting" (no aggregator).

Verification links:

• USPTO Assignment Center (current portal): https://assignmentcenter.uspto.gov/
• Legacy Patent Assignment Search (indexes back to Aug 1980): https://assignment.uspto.gov/patent/index.html
• Google Patents record (no legal-event ownership changes): https://patents.google.com/patent/US3023899/en

Confidence and limitations: I could not run the interactive Assignment Center query myself in this session (search-based access only), and I could not retrieve any pre-1980 recorded-assignment PDF. My "no records" finding is therefore well-supported for the post-1980 online database and for Google Patents, but a definitive statement about 1957–1979 paper records would require a manual pre-1980 reel/frame search at the USPTO — which I did not perform and do not claim to have performed.

I'll research US patent 3,023,899 and each of its cited references.

Let me get more detail on the Schwartz reference (US 2,791,329) and the family member US 3,156,362.

Prior-Art Analysis — U.S. Patent No. 3,023,899

1. Confirmation of the target patent (USPTO record)

Note on method: I was not able to query USPTO PatentCenter directly (it requires authenticated access and was not reachable via my search tool). The bibliographic record below is drawn from the record page at https://patents.google.com/patent/[US3023899](/patent/US3023899)/en, which mirrors the USPTO front-page data, cross-checked against Espacenet. I flag this so you do not treat it as a direct USPTO-PatentCenter pull.

Discrepancy to flag: the front page states Class 209‑88, while Google's automated classification assigns B07C 5/00, 5/04, 5/08 (postal/solid‑article sorting by electrically measured size). These are consistent in substance (sorting by measured size) but are not the same classification scheme. I report both literally rather than reconciling them.

Also, family/sibling: US 3,156,362 ("Limit control apparatus," Ethicon, filed 1962‑02‑16, granted 1964‑11‑10) shares the 1957‑12‑24 priority. It post-dates US 3,023,899 and is therefore not prior art to it.

2. Prior-art references cited on the face of US 3,023,899

The patent's "References Cited" lists exactly three U.S. patents:

1. US 2,479,051 — Sunstein — Aug. 16, 1949
2. US 2,564,221 — Hornfeck — Aug. 14, 1951
3. US 2,791,329 — Schwartz — May 7, 1957

(An OCR artifact in one scanned copy renders the Hornfeck number as "2,564,291"; the correct cited number is 2,564,221, confirmed by the US2564221A record. I note the anomaly rather than silently correcting it.)

2A. US 2,479,051 — "Alternating current type limit bridge"

• Full citation: David E. Sunstein, assignor to Philco Corp., U.S. Patent 2,479,051, "Alternating current type limit bridge," filed Apr. 12, 1945, issued Aug. 16, 1949.
• Dates: priority/filing 1945‑04‑12; publication 1949‑08‑16.
• Brief description (from the specification): A multiple‑limit AC bridge for testing and sorting resistors. The bridge has a standard arm and an "unknown" arm meeting at a common junction (terminal 9, groundable), with several tolerance‑limit arms made of series resistor pairs (3‑4, 5‑6, 7‑8, 9‑10, 11‑12) whose ratios are set to different percentages (e.g., −10%, −5%, 0%, +5%, +10%). AC excitation is fed through a transformer (15). Each arm's output feeds an amplifier (21–25) and then a phase‑sensitive discriminator (26–30) comparing the bridge signal against a reference phase. Because the bridge output is at 0° or 180° depending on whether the unknown is above or below each ratio, the discriminators drive indicator/control circuits (lamps; relays actuating trap‑door chutes in FIG. 6) to classify the part. A suitable phase‑discriminator circuit is shown in FIG. 4 (double triode + polarized relay).

Relevance to US 3,023,899 (potential § 102):
This is the closest structural reference. It discloses, in substantially the claimed arrangement:

• a first pair of legs (standard/unknown) common to a plurality of bridge circuits,
• a plurality of sets of series‑connected impedances of known value (the tolerance resistor pairs) of different, progressively graduated ratios, connected to form the parallel bridges sharing the common side,
• means for impressing a potential difference across the bridges (transformer 15),
• individual means for detecting the direction of unbalance of each bridge (amplifiers + phase discriminators), and
• output/indicator circuits per bridge.

Claims it could potentially anticipate under § 102: claims 1, 4, and arguably 10 (the graduated‑ratio range and "detecting means … for the one of said bridge circuits at one limit of said range for controlling the remaining said detecting means"), and 11.
Where it falls short / likely § 103 instead: Sunstein's variable element is a static device‑under‑test, not "means responsive to variation of said physical condition for varying the voltage ratio" continuously and progressively over a dynamic range; and its lamps/relays are not clearly "separate storage circuit[s] … for storing an indication of the extent of said unbalance" (claim 1) nor a gated start/stop "operating interval" (claims 2, 11, 12). Those are the probable points of novelty — which is why the examiner most likely used Sunstein as a primary § 103 reference rather than as a clean § 102 anticipation.

2B. US 2,564,221 — "Electromagnetic motion responsive device"

• Full citation: Hornfeck, assignor to Bailey Meter Co., U.S. Patent 2,564,221, "Electromagnetic motion responsive device," filed Jan. 22, 1948, issued Aug. 14, 1951.
• Dates: filing 1948‑01‑22; publication 1951‑08‑14.
• Brief description (from the specification): A movable‑core differential transformer (LVDT). A primary winding is energized from an AC source, with pairs of secondary windings arranged in various relative positions (FIGS. 1–7); a magnetic core member moves in response to a variable condition (exemplified by pressure acting on a bellows, FIG. 2). Core movement progressively raises the coupling to one secondary and lowers it to the other, producing output voltages that vary in linear relation with the condition. The secondaries are connected in series‑aiding or series‑bucking, and the derived voltage is applied to a balanceable network with a slide‑wire potentiometer, an amplifier/motor control, and phase‑sensitive rebalancing.

Relevance to US 3,023,899 (potential § 102):
This reference supplies the transducer sub‑combination recited in dependent/independent claims 3, 5, and 13 ("a differential transformer including a movable core," "an infinitely variable voltage divider … including an operating member," core moved in response to displacement to vary the voltage ratio linearly). Hornfeck's movable core, pairs of secondaries, series‑aiding/bucking connection, and linear output correspond closely to the transformer 55 / core 60 / secondaries 71‑72 arrangement of US 3,023,899.

Claims it could potentially anticipate: none in full. Every independent claim of US 3,023,899 additionally requires the plurality of parallel bridge circuits with a common first side and graduated second sides and individual unbalance‑direction detecting means. Hornfeck discloses a single balanceable network, not that multi‑bridge architecture. Accordingly Hornfeck is best characterized as a § 103 reference for the transducer element, not a standalone § 102 anticipation of any whole claim.

2C. US 2,791,329 — "Article gauging, classifying, sorting, and counting apparatus"

• Full citation: Schwartz, assignor to Ethicon, Inc., U.S. Patent 2,791,329, "Article gauging, classifying, sorting, and counting apparatus," filed Feb. 13, 1952, issued May 7, 1957.
• Dates: filing 1952‑02‑13; publication 1957‑05‑07. (Issued ~7 months before the Dec. 24, 1957 filing of US 3,023,899, so it is valid prior art; and it is same‑assignee Ethicon art.)
• Brief description (inferred from US 3,023,899's own text): Apparatus for gauging, classifying, sorting and counting articles (specifically surgical sutures), using gates A2, B2, C2 and solenoids A3, B3, C3 (and A6/B6/C6/R6 counters), and a reject path, to sort articles into categories — including categories defined by upper and lower dimensional limits. US 3,023,899 repeatedly incorporates it by reference as the structure of its sorting station 16, collecting station 19, and the source of its "gate A2, solenoid A3" nomenclature.

Relevance to US 3,023,899 (potential § 102):
This is the system‑level / application‑level reference. It discloses the gauging‑and‑classifying of finite‑length articles with conveying means, a sensing/gauging mechanism, recording/indicating means, and category‑controlled sorting — i.e., the environment recited in claims 7, 8, 9, 12, and 13.

Claims it could potentially anticipate: none in full. The characterizing feature of US 3,023,899 — the plurality of bridge circuits having one side in common with graduated second sides and individual direction‑of‑unbalance detectors — is not what Schwartz is relied on for; the two patents are complementary, not anticipatory of each other. Schwartz is therefore a § 103/background reference for the classifying apparatus claims and the "one of said voltage dividers … controlling said indicating means" (claim 2) / gate‑control concepts.

3. Summary table

4. Bottom line and explicit qualifications

• Most relevant single reference: US 2,479,051 (Sunstein). It is the only one of the three that discloses the core architectural idea of multiple bridge circuits of graduated, known ratios with common legs and individual phase‑sensitive direction‑of‑unbalance detection. It potentially bears on claims 1, 4, 10, 11.
• US 2,564,221 (Hornfeck) covers the differential‑transformer transducer feature (claims 3, 5, 13 sub‑combinations) but not the multi‑bridge architecture.
• US 2,791,329 (Schwartz) covers the sorting/classifying application and control relays (claims 7, 8, 9, 12, 13 environment) but not the electrical multi‑bridge architecture.
• No single cited reference appears to be a clean, complete § 102 anticipation of any whole claim, because each independent claim requires the combination of (a) the common‑side, graduated multi‑bridge network, (b) individual unbalance‑direction detectors, and (c) the recited storage / interval‑gating features — and the cited references each supply only part of that combination. The realistic attack on US 3,023,899 is therefore a § 103 combination (e.g., Sunstein as primary in view of Hornfeck and/or Schwartz), which is consistent with these having been cited as "References Cited" rather than as specific § 102 rejections.

Qualifications:

1. I could not retrieve the actual examiner‑vs‑applicant citation markings or the Office Action history; I cannot state which of these references the examiner actually applied under § 102 versus § 103. My claim mapping is analytical, based on the printed specifications and the claim language.
2. I could not open the full texts of US 2,791,329 or US 2,479,051 end‑to‑end; the descriptions above rest on the excerpts retrieved and on US 3,023,899's own characterization of Schwartz. Where a claim element turns on the precise wording of those references (e.g., whether their indicators constitute "storage circuits"), I flag that as arguable rather than settled.
3. Per the operating rule, all patent numbers are interpreted literally; the "2,564,291" string seen in one OCR snippet is reported as a scanning artifact of US 2,564,221, not as a separate reference.

I'll verify what I can about the three cited references before building the § 103 analysis.

Obviousness Analysis Under 35 U.S.C. § 103 — US 3,023,899 ("Limit Control Apparatus")

Scope note: This analysis builds on the previously generated summary, technical-context, plain-language-claim, litigation, and caveat sections above and does not repeat them. It uses the prior-art references appearing in the "References Cited / Citations" section of the US 3,023,899 record:

I verified content for Sunstein and Hornfeck by retrieving their specifications (Google Patents and a FreePatentsOnline mirror for the Sunstein text). I could not retrieve the full text of Schwartz; my description of it rests on the title, the assignee, and how US 3,023,899's own specification incorporates it.

I. Legal framework applied

• Pre‑AIA § 103(a) governs: the application was filed 1957‑12‑24, before the 2011 AIA amendments and before KSR. I nonetheless apply the modern objective framework — Graham v. John Deere, 383 U.S. 1 (1966); KSR Int'l Co. v. Teleflex Inc., 550 U.S. 398 (2007) — while noting that the 1952 Act's "invention" standard and the stricter post‑Graham TSM formulations of the 1960s–70s would have applied at the time.
• Prior art under § 103 must itself qualify under § 102(a), (b), (e), (f), or (g). Sunstein and Hornfeck both qualify under § 102(b).
• The references were of record and were presumably considered by the examiner before the 13 claims were allowed. That does not immunize the claims, but it shifts the burden of explanation onto any obviousness theory: a valid theory must explain why the claimed combination was nonetheless not suggested. I address this in §VII.

Level of ordinary skill in the art (POSITA), circa December 1957: a person with a bachelor's degree in electrical engineering (or equivalent training) and roughly 3–5 years of experience in AC bridge instrumentation and/or automated gauging-and-sorting machinery — the intersection of the Sunstein, Hornfeck, and Schwartz fields. This level is inferred from the subject matter itself (Okajima factors) and is not a record-based finding.

II. What each reference discloses (verified)

A. Sunstein, US 2,479,051 — the primary reference

Sunstein's text (retrieved via the FreePatentsOnline mirror, https://FreePatentsOnline.com/[2479051](/patent/2479051).html; also https://patents.google.com/patent/US2479051) discloses far more than its title suggests. Direct quotations from the retrieved specification:

• A plural-limit bridge with a shared comparison side and a plurality of graduated second sides. "the standard against which the unknown is to be compared is arm 1 of the multiple limit bridge. The unknown is arm 2 of this bridge." "The various tolerance limits are set up by resistor combination such as 3-4, 5-6, 7-8, or 9-10, or 11-12." "R-3 and R-4 may be selected such that the ratio of R-4 to R-3 is 0.90… R-10, divided by R-9 is set to be 1.05." Sunstein thus builds one bridge side (arms 1 and 2) common to a plurality of ratio sets (0.90, 0.95, 1.00, 1.05, 1.10) that differ from each other by predetermined graduations — the exact "first side in common / several second sides of different ratio" topology recited in claim 1.
• Direction-of-unbalance detection by phase, per limit. "if the potential from line 13 to line 14 is chosen as the standard phase reference, the following conditions obtain: When the unknown is higher than the ratio set up by the tolerance limit arms… the output potential of the bridge has a zero phase angle, and when the unknown resistor is smaller than the appropriate tolerance, the output potential of the bridge has… a phase angle of 180 degrees." So each limit circuit's output phase encodes the direction of unbalance — the same physical quantity claims 1–13 make the object of "individual means for detecting the direction of unbalance in each of said bridge circuits."
• A phase-sensitive discriminator per limit, referenced to the excitation. "Figure 3 shows the series of amplifiers, phase discriminators and indicators or controls in block diagram form"; "Figure 4 shows one of the phase discriminators." Sunstein's Fig. 4 discriminator is "The double triode 35'… signal fed to its grids… the reference input phase is supplied through transformer 31 and input terminals 38." This is structurally and functionally the amplifier-array-plus-reference architecture of US 3,023,899's squaring amplifiers A–Aₙ and discriminators D–Dₙ.
• Indicator/control circuits — the ancestor of the "storage circuit." Sunstein's discriminators drive "indicator or control mechanisms 33, 34, and 35" and "indicator or control circuits," and its Fig. 4 text mentions a "Relay 42 may be a polarized…" relay. So relay-type indication/control per limit is disclosed.
• Automatic classification into categories. "FIG. 6 represents a form of classification chute. Resistors entering top 56 fall vertically down the chute until they strike a trap door obstruction such as 63. When they strike such an obstruction, they are shunted off into a side chute and in this case fall into the box 13. The control of the trap door is obtained from the phase discriminator through the indicator or control circuit." Sunstein therefore discloses the entire "compare-against-multiple-graduated-limits → detect direction of unbalance → actuate a sorting gate" chain, for the express purpose of classifying a manufactured article by how far a measured property departs from a standard in either direction.

What Sunstein does not have: (i) a continuously variable voltage divider whose ratio is driven through a range by a physical condition (its arm 2 is a fixed-value resistor under test, i.e., a single-point comparison rather than a swept measurement); (ii) the specific two-leg common side formed by a differential transformer; (iii) thyratron latching storage per detector; and (iv) a scheme in which one limit circuit gates/energizes the others.

B. Hornfeck, US 2,564,221 — the transducer reference

Hornfeck (https://patents.google.com/patent/[US2564221A](/patent/US2564221A)/en; PDF https://patentimages.storage.googleapis.com/63/af/51/0699bc4685d888/US2564221.pdf) discloses a linearly variable differential-transformer-type motion transducer — a primary, two pairs of secondaries, and a movable magnetic core whose displacement varies the coupling, with:

• "An object of my invention is to provide… a measurable effect varying in linear relation with changes in a variable condition. Still another object is to provide a device for producing a plurality of effects representative of a variable condition and varying in linear relation with changes in the condition."
• "the output of the devices… may be applied to any suitable and well known electrical circuit to provide either an indication of the condition or an indication of some function of different conditions."
• "these pairs of secondary windings are connected in opposite branches of a balanceable network, and the device… operates on an unbalance of this network…"
• "In each form of my invention the windings of each pair of secondaries are connected either in series bucking or in series adding… the connections for either one or both could be reversed."

So Hornfeck expressly teaches (a) a variable voltage divider in the form of a movable-core transformer, (b) driven by a mechanical displacement, (c) producing outputs linear in the variable, (d) intended to be wired into a balanceable network / bridge, and (e) the same series-aiding connection of secondaries (71/72 in US 3,023,899) with the option to reverse the leads — which is precisely the "reverse the leads to measure maximum diameters" teaching of the subject patent's own specification.

C. Schwartz, US 2,791,329 — the handling/classification reference

Title, assignee (Ethicon, Inc.), and the US 3,023,899 specification together establish that Schwartz discloses apparatus for gauging, classifying, sorting, and counting articles, with gates A2, A3, etc. and solenoids A3, B3, A6, B6, C6, R6, and a reject path. US 3,023,899's specification expressly states the sorting station "may be of the structure shown in Schwartz Patent 2,791,329," and further states that the transfer relays "might correspond directly to the solenoids A3, B3, etc. in the Schwartz patent." I have not retrieved Schwartz's text, so I treat it as teaching article-handling, multi-category sorting, and counting, not as to un-retrieved specifics.

III. Grounds of rejection

Ground 1 — Claims 1 and 2 over Sunstein

Sunstein alone discloses the heart of claim 1: a bridge whose comparison side (arms 1/2) is common to a plurality of second sides ("resistor combination such as 3-4, 5-6, 7-8, or 9-10, or 11-12") each of a different ratio (0.90–1.10); a common source ("Power is fed into the bridge through transformer 15"); and an individual detector per limit (discriminators 26–30) that senses the direction of unbalance (0° vs. 180° phase).

The differences over claim 1 are: (a) the divider varied "responsive to variation of said physical condition… through a range"; and (b) "a separate storage circuit connected to each of said detecting means." For (a), the specification's own statement that the transformer "offers practical advantages of range and sensitivity… over other variable voltage dividers capable of use therein" concedes that variable voltage dividers in the common arm were known alternatives, and Sunstein itself calls its output a function of a "variable physical condition" (the resistance under test). For (b), Sunstein's "indicator or control circuits" and its Fig. 6 classification chute necessarily retain which limit was crossed long enough to route the article, and relay-type per-limit control (its relay 42) is disclosed. Any residual gap is supplied by the routine use of a latching relay (or, as in the subject patent, a thyratron) as a per-channel memory element — a predictable, well-known expedient.

Claim 2 adds, over claim 1, individually adjustable second-side dividers and a time-gating function driven by one of them. Sunstein's tolerance arms are adjustable by selection of resistor combinations ("The various tolerance limits are set up by resistor combination"), and the gating of detection by the extreme limit circuit is developed in Ground 4.

Ground 2 — Claim 1 (and claims 3, 5, 6) over Sunstein in view of Hornfeck

The single difference of substance over Sunstein — a continuously variable divider in the common side, swept through a range by a sensed physical condition — is met by Hornfeck. A POSITA seeking to convert Sunstein's static limit bridge into a continuous gauging instrument would substitute Hornfeck's movable-core differential transformer for Sunstein's arm 2, because Hornfeck is a known, commercially exploited (Bailey Meter) transducer whose express objects — linear output over a range, high sensitivity to "very slight movements," and "a plurality of effects representative of a variable condition" — match the gauging problem the subject patent states (resolving ~0.003 in over a ~0.040 in stroke).

• Claim 3 is this combination with the transducer expressly a "differential transformer including a movable core" — i.e., Hornfeck verbatim — and with "storage relays" for the storage means, which Sunstein's relay-based indicator/control circuits and the routine relay art supply.
• Claim 5 ("infinitely variable voltage divider… operating member") likewise reads on Hornfeck's core-and-winding divider, with "first change… during each said interval" being a routine latch-once function.
• Claim 6 (continuous thickness comparison) is this combination plus a conveying path and a sensing member displaced by the moving element — the gauging-wheel arrangement described in US 3,023,899 itself and the automated-handling context of both Schwartz and Sunstein's chute.

Ground 3 — Claims 7–9, 12, 13 over Sunstein + Hornfeck + Schwartz

Claims 7, 8, 9, 12 and 13 add only classification of successive articles to the Sunstein+Hornfeck structure. Sunstein itself already classifies by the direction-of-unbalance outputs ("resistors… fall vertically down the chute until they strike a trap door obstruction… The control of the trap door is obtained from the phase discriminator through the indicator or control circuit"), and Schwartz supplies the article-handling, multi-category gate/solenoid, leading-edge/trailing-edge, and counting implementation. The strongest motivation on the whole record is the subject patent's own specification, which twice directs the reader to Schwartz for the sorting station and says the transfer relays "might correspond directly to the solenoids A3, B3, etc. in the Schwartz patent." A reference incorporated by the applicant's own specification is the paradigm case of a suggested combination.

Ground 4 — Claims 2, 4, 10, 11 (and the "gate" limitations of 12, 13) over Sunstein + Hornfeck + Schwartz, in view of the recognized design need

These claims cover the one architectural feature Sunstein does not disclose: using one limit circuit (the minimum/zero-tolerance bridge) as a gate to energize, time, and reset the remaining detectors. This would be asserted as the point of novelty. It is nonetheless an obvious design choice:

1. Recognized problem, known solution. The subject patent itself states the problem the gate solves: when the gauging wheels re-close at the trailing end of an article, "in fact [conditions] establish conditions causing all remaining thyratrons to fire," and the gate blocks transfer of this "erroneously fired" information. Gating a detector bank on and off with an article-present signal is the standard, predictable way to suppress end-of-cycle transients in article-handling machinery — the very class of machinery Sunstein and Schwartz address.
2. The gate signal is already generated. Sunstein's 0.90-ratio (most extreme) limit circuit produces a discriminated output exactly when the unknown crosses the extreme boundary; the subject patent's P₀ circuit is simply that extreme circuit set "only slightly greater than zero." Using an existing end-of-range output as a cycle-start/end marker is a "predictable variation" barred by KSR ("A person of ordinary skill is also a person of ordinary creativity").
3. Reset is inherent in the sorting cycle. Schwartz's successive-article counters and gates require clearing/resetting between articles; claim 4's "reset… indicating means" and claims 11–13's "deenergizing and resetting said recording means" are routine housekeeping.
4. Claims 11 and 12 merely spell out the timing and the trailing-edge reset that the gate inherently performs; claim 13 is claim 12 with the Hornfeck transformer expressly recited.

IV. Claim-by-claim disposition (summary table)

In each row the recited elements perform their known functions and the combination produces only predictable results — the classic aggregation/Sakraida rationale, reinforced by KSR's "combination of familiar elements according to known methods is likely obvious."

V. Motivation to combine (articulated)

1. Same field of endeavor / same problem. Sunstein classifies manufactured articles (resistors) into boxes by comparing them against graduated standard limits; the subject patent classifies manufactured articles (sutures) into chambers by comparing them against graduated standard limits. The problem — "multiple graduated thresholds applied to one measured article, then sort it" — is identical.
2. Physically combinable. Hornfeck's transducer is expressly designed to be wired into "a balanceable network" in the place of a bridge arm; substituting it for Sunstein's fixed arm 2 requires no redesign of the detection chain and no new principle.
3. Art-recognized equivalence. The specification concedes other variable voltage dividers were "capable of use therein," and Hornfeck's device is a commercially sold embodiment (Bailey Meter) of exactly that class.
4. Express incorporation of Schwartz. The strongest and most objective motivation: the applicant's own specification twice defines the sorting station by reference to Schwartz 2,791,329 and identifies the subject transfer relays with Schwartz's solenoids A3, B3, etc.
5. Design need / market pressure. High-speed (1,000 ft/min) automated suture manufacture demands continuous, non-contact, high-sensitivity gauging and end-of-article gating — the exact objectives stated in the patent's own "objects" section, which are stated problems, not results; stating a problem does not make its solution nonobvious.
6. Predictable results, expected utility. Each claim's benefit (finer resolution, category sorting, suppression of spurious end-of-cycle firings) follows directly and predictably from the known functions of the combined elements.

VI. What the applicant would argue (and the counter)

VII. Secondary considerations and burdens

• No objective indicia are of record — no evidence of commercial success, long-felt need, unexpected results, copying, or industry praise with a nexus to the claims. Absent such evidence, the Graham secondary factors do not rebut a prima facie case.
• Examiner consideration cuts both ways. Sunstein, Hornfeck, and Schwartz were all cited on the face of US 3,023,899. The examiner allowed 13 claims over them. Reasons for allowance cannot be assessed without the file wrapper (§VIII). A modern obviousness challenge must therefore explain what the examiner likely did not articulate: the combination motive (why a POSITA would substitute Hornfeck's swept transducer into Sunstein's multiple limit bridge, and gate the detector bank on an extreme-limit output). That motivation is well supported by the patent's own specification and by the shared problem of the references.

VIII. Explicit caveats and items requiring verification

1. Schwartz's § 102 status is date-sensitive. US 2,791,329 issued 1957‑05‑07, within one year of the 1957‑12‑24 filing, so § 102(b) is unavailable. It can serve as § 103 art only if it qualifies under § 102(a) (i.e., dated before the applicant's invention) or § 102(e)/(f)/(g). If the invention was made before May 1957 — plausible given the same-assignee relationship and the specification's familiarity with Schwartz — Schwartz may drop out as prior art in a strict sense, leaving Sunstein and Hornfeck (both solid § 102(b) art) to carry the classification limitations. I flag this because Schwartz is the reference carrying the most "motivation" weight, yet its prior-art date is the weakest.
2. I did not retrieve Schwartz's specification. My description of it is inferred from its title, assignee, and US 3,023,899's own statements. Any conclusion resting on Schwartz's internal disclosure is provisional until its text is checked.
3. I retrieved only partial text of Sunstein and Hornfeck. The quotations above are verbatim from the retrieved portions (FreePatentsOnline mirror for Sunstein; Google Patents / USPTO PDF for Hornfeck). Their full claims and any un-retrieved passages (e.g., Sunstein's own treatment of storage or latching) have not been read in full.
4. No prosecution history. I have not reviewed the file wrapper, so I cannot state the examiner's actual reasons for allowance or whether Sunstein/Hornfeck were applied and overcome on the merits. The 1957 "means for…" claim style also invites § 112, sixth paragraph, construction, meaning the comparison must ultimately be made against the disclosed structure (thyratron latches, discriminators D–Dₙ, P₀ gate) — which is exactly the structure the references are argued to suggest.
5. "Similar documents" with post-filing publication dates (e.g., US 3,089,594; US 3,092,020; US 3,046,533; US 2,931,943; US 2,925,983) are not established prior art on the record shown; their publication dates post-date the 1957‑12‑24 filing, and whether they qualify under § 102(e) depends on filing dates not supplied on this page. I have not treated them as prior art, but if any has a pre‑1957 U.S. filing date they could independently support the "multiple parallel bridges sharing a common arm" and "classification by graduated thresholds" limitations and should be checked.
6. OCR artifacts in the fetched text (e.g., "diiferent," "passe," "wheels 12-43," "2,564,291" for Hornfeck's number in one OCR passage) have not been silently corrected; patent numbers and claim language are reproduced as they appear in the source.

IX. Bottom line

On the prior art of record, all 13 claims of US 3,023,899 are vulnerable to a § 103 rejection, chiefly on Sunstein (US 2,479,051) as the primary reference, which discloses a plural-limit AC bridge with a shared comparison side, a plurality of graduated ratio arms, per-limit direction-of-unbalance phase discriminators, and phase-controlled classification chutes. The claims' distinguishing features are supplied by known, art-recognized expedients: Hornfeck (US 2,564,221) for the continuously variable, movable-core differential-transformer divider; Schwartz (US 2,791,329) — expressly incorporated by the applicant's own specification — for the successive-article sorting/handling and reset; and routine relay/latch and gating practice for the per-channel storage and the interval gate (claims 10–13). The strongest counter-argument available to a patent owner is the timing/prior-art status of Schwartz and the absence of a squarely disclosed multi-branch "parallel" bridge topology in Sunstein — points that should be verified against the full texts and the file wrapper before relying on this analysis.