US 4024957

Summary — US 4,024,957

Important scope note first: I searched for exactly 4024957 (US) and for CAFC 2026 docket activity tied to it. The CAFC/docket query returned no litigation or appeal records for US 4,024,957 — the only "4024957" hit was the unrelated EP application EP 4 024 957 A1 ("Bluetooth pairing method," Huawei), which is a different number series and a different subject matter. So I can confirm the patent bibliographic/bibliographic content below, but I have no authoritative evidence of any 2026 CAFC proceeding involving this patent. If such a docket exists, it is not surfacing in the sources I can reach; I won't speculate about one.

Bibliographic data (from the patent record)

Assignment history (as recorded, useful for ownership tracing): 1981-06-05 mortgage to a consortium (First Wisconsin Bank of Green Bay, Prudential, First National Bank of Chicago, Continental Illinois, First Wisconsin National Bank of Milwaukee) by Northwest Engineering Co.; 1992-04-06 security interest to IBJ Schroder Bank & Trust by Terex Corporation; 1995-01-26 release/reassignment to Terex Corporation. (Sources: Google Patents "Legal Events" for US4024957A; https://patents.google.com/patent/US4024957A/en)

Abstract (as issued)

A carrier-mounted crane has inner and outer boom sections securable together at upper and lower connections. To pivotally fold the outer boom beneath the inner boom, the lower connection is a folding compound arm extending between the boom sections and pivotable intermediate its ends. When the upper connection is released and the outer boom folded under, the boom's main pivot to the compound arm shifts longitudinally away from the inner boom section, effectively moving the outer boom away from the carrier, so the tip of the folded outer boom stays clear of carrier structure (e.g., the operator's platform).

Plain-language overview of the independent claims

There are 7 claims; claims 1, 3, and 7 are independent (2 depends on 1; 4→3; 5→4; 6→5).

• Claim 1 — the core fold-and-shift structure. A crane mounted at its rear on a carrier, with an inner boom section and an outer boom section that folds rearward for retraction. The key feature: a means that shifts the inner (rear) end of the outer boom forward of its normal position when folded. That means is at least one compound arm running between the boom sections and projecting forward from the inner section. The arm pivots at a fixed transverse axis located substantially forward of the inner boom section — and also forward of the inner terminus of the outer boom when extended. Both ends of the compound arm are fixed to the respective boom sections; the arm is two legs joined at an intermediate pivot; the legs are coextensive when the boom is extended and non-coextensive when folded. (This is essentially a scissor-link that lengthens the effective pivot reach as it folds.)

• Claim 3 — claim 1's structure plus a positive lock. Same shifting compound-arm arrangement, but reciting that each leg has an opening remote from the intermediate arm pivot; when extended, the legs are coextensive and those openings are coaxial, and a removable locking member (the specification's shafts 21/cotter pins 22) runs through the coaxial openings to lock the sections together — removing it unlocks the sections so the outer section can fold.

• Claim 7 — broader variant. Same crane/inner/outer/shift concept, but the compound arm is defined more generically as a pair of pivotally connected legs whose pivot point lies outwardly and forwardly of the inner boom section, with the legs mutually coextensive end-to-end when the outer boom is extended. Claim 7 is the least structurally burdened of the three independents — no fixed-axis recitation, no locking-opening recitation — and so reads as the broadest claim, with claim 1 next and claim 3 the narrowest/most specific of the trio.

Technical / legal observations worth flagging

• The inventive point is a specific fix for a known geometry problem: a longer outer boom section, when folded back over a mobile carrier, would strike the cab/platform (element 23). The compound arm moves the fold pivot outward so the folded boom clears the carrier without shortening the boom.
• The specification explicitly says the boom could alternatively fold up and over (not just beneath), and that the boom could be mounted at the rear of the platform — so the terms "front/rear" in the claims are meant to be read functionally ("the pertinent language as to front and rear ... should be so interpreted").
• Dependents add conventional adjuncts: holding means for the folded boom (bracket + chain, claims 4–5) and a skid on the outer tip for ground-travel during retraction (claim 6). These are the kind of add-on features that would not likely impart independent patentable weight.

Uncertainty / caveats

• No CAFC 2026 docket entry for US 4,024,957 was located. Absence of a search hit is not proof of absence; I simply could not corroborate any appeal, and the patent has been expired since the mid-1990s, making active appellate litigation on this patent unlikely (though it could theoretically appear in a dispute over a later, related patent).
• Bibliographic values above come from the Google Patents record for US4024957A and are consistent with the full text provided; I did not independently re-verify them against the USPTO Patent Center or the printed patent front page in this session, so treat assignee-name spellings (e.g., "NORTHWEST ENGR Co") as the database's rendering rather than the printed page's.

I'll search for litigation involving US patent 4024957 across the sources you specified.

Let me search the litigation-specific sources you mentioned.

Litigation Search Results: US Patent 4,024,957

Bottom line: I found no known litigation involving US Patent 4,024,957. No district court infringement action, declaratory judgment action, ITC investigation, or PTAB proceeding naming this patent appears in the sources searched.

What the patent is

• Patent: US 4,024,957 — "Crane with foldable boom"
• Inventor: Jerome J. Schleis
• Assignee: Northwest Engineering Co. (later associated with Terex Corporation via assignments)
• Filing date: July 25, 1975 | Grant date: May 24, 1977
• Status: Expired – Lifetime; anticipated expiration May 24, 1994 (i.e., the 17-year term in force at the time)
• Claimed subject matter: a folding "compound arm" lower connection between inner and outer boom sections that lets a lengthened outer boom fold without striking the carrier (claims 1–7).

Sources searched and findings

Important caveats (stated explicitly, per operating rules)

1. Absence of evidence ≠ proof of no litigation. I could not access live PACER docket search or Westlaw/Lexis/Docket Navigator, which are the definitive tools for a complete litigation history. My search covered free portals and open web sources only.
2. Pre-digital era coverage is sparse. This patent was most likely to have been asserted (if ever) in the late 1970s–1980s — a period before PACER existed (PACER dockets generally begin ~1988–1990) and before most free/open litigation databases. Any 1970s–1980s case would rarely appear in the sources I could query.
3. The patent expired in 1994, so any enforcement window closed then; no modern NPE/serial-litigation activity is plausible.
4. The assignee/security records (First Wisconsin Bank of Green Bay, Prudential, First National Bank of Chicago, Continental Illinois, IBJ Schroder, and the release to Terex Corporation) reflect financing/mortgage security interests, not litigation.

Recommended next steps to confirm definitively

• PACER Case Locator (pcl.uscourts.gov) — search "4,024,957" as a patent number across all district courts (note limited pre-1990 coverage).
• Docket Navigator or LexisNexis/Westlaw litigation databases (paid) for a compiled patent litigation report.
• USPTO Patent Assignment / Patent Examination Data: exhaustive, but shows only assignments, not lawsuits.
• Federal Circuit and regional reporter archives (F.2d/F. Supp.) for the 1977–1994 window if a paper-era case is suspected.

If you'd like, I can draft a formal "no litigation found after reasonable search" declaration with the specific databases queried and their coverage limitations, suitable for a due-diligence or Rule 11 context.

PTAB / AIA Trial Report — US 4,024,957 ("Crane with foldable boom")

Prepared 2026-09-29. Authoritative proceeding list sourced from the structured "PTAB proceedings on file" block (USPTO Open Data Portal ingest), supplemented by web search of PTAB and Federal Circuit sources per the task instructions.

Proceedings overview

Total AIA trial proceedings on file: 0 — zero IPRs, zero PGRs, zero CBMs; thus 0 active, 0 with claims invalidated, 0 with claims sustained, 0 settled, and 0 institution denials. The bottom line for a defendant is stronger than "hardened patent" or "dead claims": US 4,024,957 expired 1994-05-24 and every one of claims 1–7 has been in the public domain for over three decades. No AIA trial was ever possible or necessary — IPR/PGR/CBM practice did not exist (IPR/PGR effective 2012-09-16) until roughly eighteen years after this patent's term ended. A demand letter citing claims 1–7 of this patent is not merely weak; it is facially untenable.

Proceedings

None. There is no proceeding to report — no IPR, PGR, or CBM number exists for this patent, and I will not invent one. The absence is not a gap in the data; it is the expected result of the patent's age.

For completeness, the enforcement-relevant chronology from the canonical sources:

Primary source: patents.google.com/patent/US4024957A/en (legal status: "Expired – Lifetime"; anticipated expiration 1994-05-24).

Strategic summary

Claim status. All claims of US 4,024,957 — independent claims 1, 3, and 7, and dependent claims 2, 4, 5, and 6 — lapsed at the end of the statutory term on 1994-05-24. None were canceled by the PTAB (no proceeding exists); none were amended; none are "sustained" in any adjudicated sense. The claims are simply expired. There is no narrower surviving claim set to design around, because there is nothing left to infringe. Note the claim set for reference: claim 1 claims the compound-arm shifting means generically; claim 3 adds the coaxial-opening/removable-shaft locking structure; claims 4–6 add the holding bracket-and-chain (claim 5) and skid (claim 6); claim 7 claims the pivotally connected legs "mutually coextensive from end to end."

Estoppel landscape — not applicable, and that is the point. Because no IPR or PGR petition was ever filed, § 315(e)(2) estoppel never attached to anyone. There is no petitioner, no real party in interest, and no privy whose hands are tied. More fundamentally, § 311(c) limits IPR to "a patent" — and while the Board has instituted on expired patents in rare circumstances, there is no economic or defensive reason for a defendant to file an IPR here: the patent has been unenforceable against post-1994 conduct for 32 years, and pre-expiration damages are barred by the six-year lookback in 35 U.S.C. § 286 and, independently, by laches/limitations principles. Practically, an IPR on this patent would be a waste of a filing fee.

Pattern signals — none. There is no repeat petitioner, no Unified Patents or other defensive aggregator in the chain, no patent-owner appeal activity, and no Federal Circuit docket to report. The recorded assignments (1981 mortgage syndicate; 1992 IBJ Schroder security interest; 1995 release to Terex Corporation) are financing instruments and post-expiration housekeeping, not assertion campaign artifacts. The examiner-cited prior art — US 2,176,731 (Stacey), US 2,689,656 (Przybylski), US 3,034,660 (Rau), GB 971,103 (Cadillon), and SE 301,039 (Tornborg & Lundberg) — is therefore academic; there is no live invalidity posture in which to deploy it.

Recommended next steps

If you are a defendant facing an assertion of US 4,024,957:

1. Do not file an IPR. There is no PTAB proceeding to join, no live claim to invalidate, and nothing to gain.
2. Lead with expiration. US 4,024,957's term ended 1994-05-24 (Google Patents legal-status record). Accused products sold, used, or imported after that date cannot infringe claims 1–7 as a matter of law.
3. Raise 35 U.S.C. § 286 against any attempt to reach pre-1994 conduct: "no recovery shall be had for any infringement committed more than six years prior to the filing of the complaint." A demand letter in 2026 reaches conduct that is 30+ years stale.
4. Treat a demand letter citing this patent as a screening signal. No competent assertion counsel would assert a patent that expired in 1994. If you receive one, preserve it — it is strong evidence of bad-faith or automated mass-demand conduct, which supports fee-shifting arguments under 35 U.S.C. § 285 (see Octane Fitness v. ICON Health & Fitness, 572 U.S. 545 (2014)) and state-law remedies.
5. Verify title independently if it matters. The chain runs Northwest Engineering Co. → Terex Corporation (via the 1995 release/reassignment). Post-expiration, ownership affects only historical damages, not defense posture. Link to the assignment records via the USPTO Patent Assignment Search if you need confirmation for a specific transaction.

If you are looking for the "absence is a signal" analysis: the usual heuristic — that well-asserted patents eventually attract IPRs — does not apply here. This patent predates the AIA trial regime entirely, so the zero-proceeding count is fully explained by chronology rather than by any implied weakness or strength of claims 1–7.

Sourcing and confidence notes

• Confidence: high that no AIA trial proceeding exists against US 4,024,957. The canonical ODP-derived block lists none, and independent web searches of PTAB/PTAB E2E-derived material, CourtListener-style sources, and general web indexed results surfaced no petition, institution decision, FWD, or appeal naming this patent. Every apparent "'957 patent" hit in those searches was a different patent (e.g., Kamstrup US 8,375,957; Fontem US 8,375,957; an ultrasonic flowmeter '957; an electronic-cigarette '957) — I have not conflated any of them with US 4,024,957.
• No proceeding numbers, judge panels, grounds, institution dates, FWD dispositions, settlement terms, or CAFC docket numbers are reported above, because none exist for this patent. Per the operating constraints, I have not fabricated any.
• Dates are given as YYYY-MM-DD throughout and are taken from the authoritative full-text record furnished in the prompt and from the Google Patents legal-status timeline.
• If your team believes a proceeding exists outside the ODP index, the operable search is a party-name search on PTAB E2E (ptacts.uspto.gov) and USPTO Patent Center for intervener/petitioner records naming Northwest Engineering Co. or Terex Corporation; I found no such record in public search.

I'll research the assignment record for US 4,024,957 using the sources specified.

I hit the tool-call limit, so the sections below are built only from what I could actually retrieve. Read the sourcing caveat first.

Sourcing caveat up front: I could not open the USPTO Assignment Center UI directly in this session (it's a JavaScript single-page app that my fetch tooling can't render). What I did retrieve is the USPTO assignment data as mirrored in Google Patents' "Legal Events" tab for US4024957A, which reproduces the USPTO reel/frame numbers, conveyance codes, assignor/assignee strings, and effective dates. Correspondents of record (the recording attorney/firm) were NOT exposed in that mirror — I will not invent them. Where the prompt asks for a correspondent, I say "not available in source" rather than guess. Verify everything against https://assignmentcenter.uspto.gov/ (or the legacy https://assignment.uspto.gov/patent/index.html) by searching patent number 4024957.

Inventors

• Jerome J. Schleis — sole named inventor on US 4,024,957 ("Crane with foldable boom"), app. US05/599,167, filed 1975-07-25.

Employer at filing: determinable only by inference from the assignee of record. The patent issued to Northwest Engineering Company as original assignee, and the assignee-of-record string on the front page is "NORTHWEST ENGR Co." That is the ordinary pattern for an employee invention assigned to the employer at filing, so Schleis is best characterized as a Northwest Engineering employee at filing. I have no independent personnel corroboration (no corporate directory, no news item) tying him to Northwest, so treat "employee of Northwest Engineering" as a strong inference from the assignment, not a documented fact.

Unusual patterns: None that suggest a fire-sale follows. This is a single-inventor patent (no co-inventor group to fragment). I found no evidence of the inventor departing the assignee within 12 months of filing — and note the front-page record shows no post-issue assignment to the inventor or from the inventor, which is the tell you'd look for if a departing engineer were clawing rights back. The only "distress" event in the chain (Northwest's early-1980s bankruptcy) post-dates filing by ~6 years and did not involve the inventor.

Original assignee

Northwest Engineering Company — named as original assignee on the issued patent (front page: "NORTHWEST ENGR Co"; the 1981 assignment instrument describes it as "a corporation of Delaware").

• Product embodying the claims — yes. The patent is drawn to a carrier-mounted mobile crane with a two-section strut/lattice boom that folds for highway travel (inner section 7 / outer section 8, compound arm 14, FIG. 1 "side elevational view of a mobile carrier crane"). Northwest Engineering was a crane manufacturer: founded 1925, making cranes, power shovels, and draglines (International Directory of Company Histories / referenceforbusiness Terex profile). A February 1987 Diesel Progress product rundown of the rebuilt Northwest line lists cranes and flamshells, woodyard cranes, magnet-masters, etc. This is squarely the product category of the claimed invention.
• Primary line of business: heavy construction equipment — lattice/strut-boom cranes, shovels, draglines, and later hydraulic cranes and excavators.
• Current status — operating predecessor, now merged into a public company. Northwest Engineering declared bankruptcy in the early 1980s; Randolph W. Lenz bought it for $1,200 in 1983, reportedly when it was about three months from liquidation; in 1988 Lenz changed the corporate name to Terex Corporation, with Northwest Engineering becoming a division. Terex Corporation is today a large, publicly traded operating company (NYSE: TEX) — so the chain ends in an operating company, not a dissolved shell. (Sources: referenceforbusiness.com Terex Corporation history; encyclopedia.com Terex Corp.; Wikipedia/Terex corporate history; Terex "Legacy Brands" pages.)

Assignment timeline

Chronological, from the USPTO assignment data as mirrored in Google Patents' Legal Events for US4024957A. Important framing: the two numbered records below are financing instruments, not title transfers. The Google Patents UI labels them under "Assigned to…," but the conveyance codes describe a MORTGAGE and a SECURITY INTEREST — i.e., the patent was pledged as collateral. Title to the patent never left the operating-company chain (Northwest → Terex) in the records I can see.

• ~1977 (presumed, not in the Legal Events list) — Reel/frame not available
  • Conveyance: Assignment (pre-issue, inventor → employer)
  • Assignor: Jerome J. Schleis (inventor)
  • Assignee: Northwest Engineering Company
  • Correspondent: not available in source
  • Context: Ordinary employee-invention assignment taken by the operating employer so the patent could issue to Northwest as assignee. This record is not reproduced in the Google Patents Legal Events tab (that tab generally shows post-issue records only); the front-page "Original Assignee: NORTHWEST ENGR Co" is the evidence it exists.
• 1981-06-01 (executed) / 1981-06-05 (recorded) — Reel 003862 / 0618
  • Conveyance: MORTGAGE (security agreement — collateral pledge, not an ownership transfer)
  • Assignor: Northwest Engineering Company, a corporation of Delaware
  • Assignees (co-lenders on one instrument): The Prudential Insurance Company of America; The First National Bank of Chicago; First Wisconsin National Bank of Milwaukee; Continental Illinois National Bank and Trust Company of Chicago; First Wisconsin Bank of Green Bay
  • Correspondent: not available in source
  • Context: Securitization / secured lending — Northwest pledged its patent estate (this patent included) as collateral to a five-lender syndicate roughly two years before its early-1980s bankruptcy.
• 1988 (no recorded instrument against this patent) — no reel/frame
  • Conveyance: Change of name / merger (Northwest Engineering Company → Terex Corporation)
  • Context: Corporate reorganization only. No assignment was recorded against US 4,024,957 for this event in the data I could reach — which is common, because a name change or merger is often recorded against a representative set of assets rather than each patent. Flagging this as a documentary gap, not a finding of a missing transfer.
• 1992-03-27 (executed) / 1992-04-06 (recorded) — Reel 006080 / 0201
  • Conveyance: SECURITY INTEREST (collateral pledge, not an ownership transfer)
  • Assignor: Terex Corporation
  • Assignee: IBJ Schroder Bank & Trust Company
  • Correspondent: not available in source
  • Context: Securitization / secured lending — the successor entity re-pledged the patent estate; consistent with Terex's heavily leveraged early-1990s balance sheet (it posted losses in 1991 and 1992 and was described as having "teetered on the brink of bankruptcy").
• 1992-07-31 (effective) / 1995-01-26 (recorded) — Reel 007312 / 0374
  • Conveyance: RELEASE OF SECURITY INTEREST AND REASSIGNMENT
  • Assignor: IBJ Schroder Bank & Trust Company, as agent
  • Assignee: Terex Corporation
  • Correspondent: not available in source
  • Context: Release — the lender discharged the 1992 lien; rights reverted to Terex. (Note the ~2.5-year lag between the stated effective date and the recording date.)

Bottom line for this section: the Assignment Center does have records for this patent — three of them — but none is a title transfer to a third party. Every ownership-relevant event is either the original inventor-to-employer assignment or a lender's lien/release. No assignment to any licensing entity, LLC, or third-party acquirer appears.

Timeline diagram

timeline
    title Ownership chain for US 4024957
    1975 : Application filed by inventor Schleis
    1977 : Patent issued to Northwest Engineering
    1981 : Mortgage recorded reel 003862 frame 0618
    1988 : Northwest Engineering merged into Terex
    1992 : Security interest reel 006080 frame 0201
    1994 : Patent term expires
    1995 : Release of security interest reel 007312 frame 0374

NPE / troll-pattern signals

1. Shell-entity transfer — not present. No licensing-only LLC anywhere in the chain. Every named assignee is either a manufacturer (Northwest Engineering, Terex Corporation) or a regulated financial institution (Prudential; First National Bank of Chicago; First Wisconsin National Bank of Milwaukee; Continental Illinois; First Wisconsin Bank of Green Bay; IBJ Schroder Bank & Trust). No "IP/Holdings/Ventures" suffix, no registered-agent address, no single-member entity in evidence.
2. Known asserter in the chain — not present. None of the reel 003862/0618, 006080/0201, or 007312/0374 parties (nor Northwest Engineering or Terex Corporation) matches the listed NPE directories (Acacia, Marathon, IV, IPNav, Wi-LAN, Mosaid/Conversant, Vringo, Pendrell, Innovatio, MPHJ, Lumen View, Round Rock, Document Generation Corp, Spangenberg entities). Terex is a product manufacturer and appears as a defendant-side/operating entity, not an asserter.
3. Repeat correspondent across the chain — unclear / not determinable. The correspondent-of-record fields are not exposed in the source I could reach, so I cannot test for a recurring recording attorney. Structurally, if any correspondent does recur here it would be lender's counsel on the matched 1992 security-interest (006080/0201) and 1995 release (007312/0374) pair — that is ordinary secured-lending practice and is not an NPE tell. I am explicitly declining to name a correspondent I have not seen.
4. Cascading transfers — not present. Only two numbered ownership-relevant events span 1977–1995, and they are 11 years apart; there is no rapid chained-LLC sequence. The single-instrument, five-lender mortgage at 003862/0618 is one transaction, not five transfers.
5. Pre-litigation transfer — not present. No infringement suit naming this patent was located (see the litigation section), so there is no 6-month transfer window to evaluate.
6. Bankruptcy fire-sale — present at the corporate level, not at the patent level. Northwest Engineering was bankrupt and was bought by Randolph W. Lenz for $1,200 in 1983 (a documented distressed acquisition). However, this patent does not appear in the record as being sold out of a bankruptcy estate; title rode along with the company through the 1988 merger into Terex. So the company was a fire-sale asset; the patent was not separately liquidated. I am flagging it because a searcher scanning for distress will hit it, but it is not a Kodak/Nortel-style patent-portfolio bankruptcy sale.
7. Privateering — not present. No operating company transferred to an NPE to assert on its behalf; the transfer chain terminates in Terex itself (an operating company), and no assertion activity exists.
8. Defensive aggregator (anti-NPE) — not present. The chain does not end at RPX, AST, LOT, Unified Patents, or OIN.

Verdict

Insufficient data.

The recorded chain consists of exactly three numbered instruments — a five-lender MORTGAGE at reel 003862/0618 (executed 1981-06-01, recorded 1981-06-05), a SECURITY INTEREST to IBJ Schroder at reel 006080/0201 (executed 1992-03-27, recorded 1992-04-06), and a RELEASE OF SECURITY INTEREST AND REASSIGNMENT at reel 007312/0374 (effective 1992-07-31, recorded 1995-01-26) — plus the unrecorded-in-this-dataset inventor assignment to Northwest Engineering. None of these is a transfer to a third-party owner, so there is no ownership change to score as an NPE event, and the patent expired 1994-05-24, closing any enforcement window. The signal set is uniformly negative (no shell entity, no known asserter, no cascading LLC transfers, no assertion activity), but because the only ownership-relevant records are the original assignment and lender liens, the correct call under your rubric is insufficient data rather than an affirmative "defensive/non-asserting" or "operating-company assertion" finding — the latter two both require facts (defensive-aggregator termination, or an actual enforcement campaign) that the record does not contain.

Verify directly: USPTO Assignment Center — search patent number 4024957 — https://assignmentcenter.uspto.gov/ (legacy interface: https://assignment.uspto.gov/patent/index.html). Confirm reels 003862/0618, 006080/0201, and 007312/0374, and, if you can access the UI, capture the correspondent-of-record field on each, which I could not retrieve. Also pull the pre-issue assignment reel for the 1977 Schleis → Northwest Engineering transfer, which the Google Patents mirror omits.

I'll search for the specific patent and each of its cited references.

Prior Art Analysis — US 4,024,957 ("Crane with foldable boom")

Search note (read first). I ran the patent number 4024957 and each cited reference through the live web. The authoritative full text supplied for this patent (source: https://patents.google.com/patent/US4024957/en) already lists the five references that the examiner cited. I could not open USPTO Patent Center / USPTO Full-Text directly in this session; the records below come from sources that mirror the USPTO data (Google Patents US4024957A/en "Patent Citations (5)" table, plus FreePatentsOnline and the 1939 Official Gazette for US 2,176,731). No similar-number substitutions are used — I excluded e.g. EP 4 024 957 (Huawei) and DE 4024957 (helmet liner), which are unrelated numbers/series.

Cross-reference to previously generated sections: the earlier summary established that claims 1, 3, and 7 are independent, and that the inventive core is the shifting means — a compound arm of two pivotally-joined legs whose intermediate pivot lies forward of the inner boom section, so the rear (inner) terminus of the outer boom moves forward as the outer boom folds. That framing drives the § 102 analysis below. No contradiction with the earlier generated sections was found.

The five examiner-cited references (as listed on the patent)

All five are flagged * (cited by the examiner) in the Google Patents record for US4024957A, i.e., they are the art the examiner actually considered — which is why they read primarily as § 103 obviousness art rather than clean § 102 anticipations (see conclusion).

Reference-by-reference

1. US 2,176,731 A — Folding mast for portable well drilling and operating apparatus

• Full citation: US 2,176,731 A, "Folding mast for portable well drilling and operating apparatus," Guy K. Claire (Torrance, CA), assignor to International‑Stacey Corporation. Application Jan. 25, 1937, Ser. No. 122,167; issued Oct. 17, 1939. 2 claims (Cl. 189‑15). (Confirms itself in the Official Gazette of the U.S. Patent Office, v.507, Oct. 17, 1939, p. 711, via HathiTrust.)
• Description: A portable well derrick/mast made in three rigid sections (base section 13, intermediate section 13a, top section 13b). The sections are connected by transverse pivot bolts 25 (base↔intermediate) and a pivot rod 30 (intermediate↔top), "these bolts also serv[ing] as fulcrums, since around the axes of which the intermediate frame section turns when being lowered to the inactive position." Raising/lowering is by cable-and-drum rigging.
• § 102 mapping: Potentially against claim 1 and claim 7 only to the extent those claims recite "a plurality of connectable boom sections" that fold to a travel position and a crane/derrick mounted on a support. It does not disclose (a) an inner/outer boom section pair folding rearwardly beneath one another, (b) a compound arm of two legs joined at an intermediate pivot, (c) that pivot located forward of the inner section, or (d) the shift of the outer boom's inner terminus forwardly on folding. Measured against the independent claims it is at best a partial anticipatory showing of the general "folding multi-section mast" environment, not of the claimed structure. It is properly § 103 art.

2. US 2,689,656 A — Crane boom having a hinged section

• Full citation: US 2,689,656 A, "Crane boom having a hinged section," Daniel F. Przybylski. Application Jan. 16, 1953; issued Sept. 21, 1954.
• Description: The title and the record confirm a crane boom with a hinged (foldable) section — the single most on-point category of art for the preamble of every claim. (The full text was not retrievable in this session; the identifying data appears in the citation tables of, e.g., US 3,276,695, US 2,529,454 and US 2004/0026350.)
• § 102 mapping: Because it is a crane boom having a hinged section, it is the reference most likely to disclose the "inner boom section / outer boom section … adapted for folding retraction" elements of claims 1, 3 and 7. What it is not shown to disclose is the compound arm (two legs, intermediate pivot, coextensive-when-extended / non-coextensive-when-folded) and the forward pivot axis — the very elements that distinguish the independents. On the present record it therefore anticipates no claim in full; it is the best § 103 base reference for the folding-boom preamble. Flag: I could not verify its internal disclosure in this session, so this conclusion is provisional and should be confirmed against its printed text.

3. US 3,034,660 A — Trailer mounted folding derrick with telescoping boom

• Full citation: US 3,034,660 A, "Trailer mounted folding derrick with telescoping boom," Edward A. Rau and Carl Rau (Hudson, S. Dak.). Application Apr. 3, 1959, Ser. No. 804,038; issued May 15, 1962. 1 claim (Cl. 212‑46); Int'l class B66C 23/34. (FreePatentsOnline 3034660; Google Patents US3034660A/en.)
• Description: A trailer-mounted derrick with a lower derrick portion and an upper derrick portion hinged to the lower portion and angularly offset, the upper portion carrying a telescoping boom. It includes an explicit locking arrangement for the raised position — "a pair of arms pivoted to said lower portion, said arms having inwardly extending ends … a transverse bar over which said ends engage," plus a pivoted lever and winch/cable control.
• § 102 mapping: The pivoted locking arms + lever are conceptually relevant to claim 2 (means remote from the arm pivot for selectively locking/unlocking the sections) and to the "removable means … for selectively locking" element of claim 3. However, the reference's arms are locking arms on a derrick/boom-hoist, not a compound arm whose intermediate pivot shifts the outer section's inner terminus forwardly on folding. It therefore does not anticipate claims 2 or 3 in full — it lacks the shifting-means antecedent on which those claims depend. § 103 art for the locking adjunct.

4. GB 971,103 A — Improvements in or relating to a towed crane with hinged telescopic mast

• Full citation: GB 971,103 A, "Improvements in or relating to a towed crane with hinged telescopic mast," Roger Benoit Cadillon. GB application No. 10842/62, filed Mar. 21, 1962; published Sept. 30, 1964; priority France, Mar. 27, 1961 (FR 856,960 / FR 1,391,657 A). Heading B8B.
• Description (from the published abstract): A towable crane whose telescopic mast (7, 8) is pivoted to a raised part (10) of a base so that, when the mast is retracted and lowered to horizontal, the two-part jib (14, 15) can be accommodated beneath the mast with the crab and operating ropes still in position. Folding is sequenced by winches/ropes and tie-rods, with bolted jib sections released to allow the jib to fold against the mast.
• § 102 mapping: Directly relevant to the "foldable … for travel" environment, and importantly to the fold-beneath geometry recited/described in US 4,024,957 (jib folded beneath the mast). It does not disclose the claimed compound arm with an intermediate pivot located forward of the inner boom section, nor the forward shift of the outer section's inner terminus. At most it shows a two-part jib (14, 15) folding under a mast — potentially a § 102(a)/(b) showing for the preamble of claims 1/3/7, but not for their characterizing elements. § 103 art.

5. SE 301,039 B — (Tornborg & Lundberg AB)

• Full citation: SE 301,039 B, assignee Tornborg & Lundberg AB. Filed 1964‑01‑27; published 1968‑05‑20. (Swedish patent; no title of record retrieved.)
• Description: Not retrievable in this session — the title/abstract did not surface, and I will not fabricate one. It is a Swedish national publication in the crane/lifting field, cited by the examiner.
• § 102 mapping: Given the absence of the disclosure text, I cannot assign a § 102 mapping to any claim. On the pattern of the other four references (all folding-boom/mast/derrick art), it most plausibly relates to the folding multi-section boom/mast environment of claims 1/7, but this is unverified. Explicit uncertainty: treat this reference as "relevant field art, disclosure unconfirmed" until its text is obtained from Espacenet/Derwent or the Swedish patent office.

Bottom line

1. No single cited reference appears to be a § 102 anticipation of any of the three independent claims (1, 3, 7). The distinguishing feature of all three independents — a compound arm of two pivotally-joined legs whose intermediate pivot lies forward of the inner boom section, making the legs coextensive when extended and non-coextensive when folded, and thereby shifting the outer boom's inner terminus forwardly on retraction — is not disclosed by any of the five references on the record available.
2. The five references are best characterized as § 103 obviousness art (consistent with their */examiner-cited status):
   • US 2,689,656 → closest to the "crane boom having a hinged section" preamble (claims 1, 7).
   • US 3,034,660 → closest to the locking/unlocking adjunct (claims 2, 3).
   • GB 971,103 → closest to the fold-beneath-a-mast/jib configuration (claims 1, 3, 7 environment).
   • US 2,176,731 → multi-section folding mast with pivot bolts/rod (claims 1, 7 environment).
   • SE 301,039 B → field art, disclosure unconfirmed.
3. If a § 102 theory is to be pressed with any of these, the only realistic target is the preamble of the broad claim 7 (crane + inner/outer sections + rearward folding), and only if the reference's interior structure is confirmed on inspection. The characterizing elements of claims 1/3/7 remain unmet.

Caveats (stated explicitly)

• I could retrieve full detail only for US 2,176,731 (Official Gazette + FPO), US 3,034,660 (FPO + Google Patents), and GB 971,103 (Google Patents abstract). The internal disclosures of US 2,689,656 and SE 301,039 B were not confirmed in this session; their mappings above are provisional.
• § 102 anticipation requires every claim element in a single reference, arranged as in the claim. My mapping identifies potential element correspondence, not a completed anticipation, and I have flagged where correspondence is absent.
• I could not access USPTO Patent Center / USPTO Full‑Text search directly; the citation set is taken from the authoritative full text supplied (Google Patents US4024957A/en), which mirrors the USPTO front‑page "References Cited." If you want the definitive PTAB/Patent Center view, query https://patentcenter.uspto.gov for application US05/599,167.

I'll ground this obviousness analysis in the actual prior-art references cited on the face of US 4,024,957. Let me pull details on the key references.

Let me pull the two references whose disclosures matter most to the "shift the pivot" concept — Przybylski and the Swedish reference.

Obviousness Analysis — US 4,024,957 Under 35 U.S.C. § 103

Patent: US 4,024,957 A, "Crane with foldable boom" (Schleis; Northwest Engineering Co.); filed 1975‑07‑25, granted 1977‑05‑24, expired 1994‑05‑24.
Prior-art set used (the five references cited on the face of the patent): US 2,176,731 A (Stacey); US 2,689,656 A (Przybylski); US 3,034,660 A (Rau & Rau); GB 971,103 A (Cadillon); SE 301,039 B (Tornborg & Lundberg).
Primary source: patents.google.com/patent/US4024957A/en.

Framing caveat up front (per the operating rules). I was able to retrieve the disclosures of Stacey (US 2,176,731), Rau (US 3,034,660), and Cadillon (GB 971,103). I could not retrieve the substantive text of Przybylski (US 2,689,656) or Tornborg & Lundberg (SE 301,039 B) — only their bibliographic records and citation entries. Where I rely on those two, I say so explicitly and mark the inference as unverified. I also note one analogous-art reference that is not on the face of the patent — Marcantonio, US 2,529,454 ("Foldable boom," 1950) — which is discussed in the closely related later document EP 0 794 149 A2 as teaching pivot-offset folding; I flag it separately because it is not part of the "Prior Art section" you directed me to use.

1. Analytical framework

Under Graham v. John Deere Co., 383 U.S. 1 (1966), and KSR Int'l Co. v. Teleflex Inc., 550 U.S. 398 (2007), I address: (a) scope and content of the prior art; (b) differences between the prior art and the claims; (c) the level of ordinary skill in the art; and (d) secondary considerations. Because the patent expired on 1994‑05‑24 and there is no litigation or PTAB record (consistent with the earlier sections of this analysis), there is no infringement/validity contest in which these art-based grounds have actually been deployed, and no secondary-consideration evidence is realistically available.

Claim construction note relevant to § 103. The independent claims recite "means to shift the inner terminus of said outer boom section…" (claim 1(c); claim 3(c), spelling "shiftng" in the printed claim). That is classic means-plus-function phrasing, but each claim immediately defines the "means" by structure ("said shifting means comprising at least one compound arm…"). Under § 112(f)/Williamson v. Citrix practice, the structure actually recited becomes the limiting construction, so I analyze the claims structurally: a two-leg (compound) arm, each leg fixed to a respective boom section, joined at an intermediate pivot, the arms coextensive when extended and non-coextensive when folded. Note also the slips in the printed claims — claim 1(e) says ends secured "to said boom sections" while claim 3(e) says "said boom section" (singular); claim 3's "shiftng" is a typographical error. I treat these as the record's literal text and do not auto-correct them.

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

A mechanical-design engineer (B.S.M.E. or equivalent) with roughly 2–5 years' experience in the design of mobile and lattice-boom cranes, derricks, and material-handling booms, including familiarity with folding/erecting linkages, hinge pins, locking arms, and transport-height constraints. All five cited references are within this exact field (folding booms/derricks for transport), so the field-of-endeavor and reasonable-expectation-of-success prongs of KSR are easily satisfied.

3. What each cited reference discloses, mapped to the claim elements

Analogous art found incidentally (NOT on the face of the patent — flagged separately): EP 0 794 149 A2 states that "[f]olding booms have been made with the pivot point moved laterally away from the neutral axis of the boom sections to allow the folding section to clear the main section, as in U.S. Patent Nos. 2,529,454 … to Marcantonio, and 3,306,470 … to Green, et al." (EP0794149A2.pdf). This is direct evidence that, before this patent's 1975 filing date, the field already knew to relocate/offset the fold pivot so the folded section clears the main section — the exact problem US 4,024,957 states it solves ("its tip portion would engage and undesirably interfere with the operator's cab or other carrier structure").

4. The differences between the prior art and the claims

The five face-cited references collectively disclose: multi-section folding booms/derricks; the section-to-section pivot pin; removable locking members at the section joint; a pivoted locking-arm linkage between the two sections; a connecting lug/link; folding under for transport; and a ground-engaging tip wheel.

What the claims add — and what no verified face reference shows — is the specific "compound arm" geometry: two legs, each leg fixedly secured to a respective boom section, joined at an intermediate arm pivot, with the arm extending forwardly from the inner section and pivoting about an axis "disposed substantially forwardly of said inner section" and forward of the inner terminus of the outer section when extended, and the legs being coextensive when extended / non‑coextensive when folded (claims 1(f)–(g), 3(f)–(g), 7(e)). The functional consequence is that the inner (rear) terminus of the outer section moves forward, away from the carrier, during folding — i.e., a stretching/translating hinge rather than a plain revolute hinge at the section interface.

So the case turns on whether it was obvious to replace the plain interface hinge (Stacey's pivot bolt 25; Przybylski's hinge; Cadillon's bolted joint) with a two-bar knuckle/link whose intermediate pivot sits outboard/forward of the inner section, to obtain the clearance that offset-pivot practice (Marcantonio/Green) already sought.

5. Proposed § 103 combinations and motivations to combine

Ground 1 — Claims 1 and 7 obvious over Przybylski in view of Rau and Cadillon

• Primary: Przybylski (US 2,689,656) — a crane boom with a hinged (foldable) section.
• Secondary: Rau (US 3,034,660) — two hinged sections with pivoted arms extending between them and a releasable lock, plus a counter-balance for controlled folding; and Cadillon (GB 971,103) — a two-part jib folded under a mast, with the sections joined by removable bolts and a lug connecting the folded section to the mast.
• Motivation (KSR): All three are in the same field (folding lattice booms for transport), address the same problem (shortening/clearing the boom for highway travel), and the combination is the predictable assembly of known hinge, arm, and latch elements with predictable results. A POSITA seeking greater folded-boom clearance would look to the connecting-linkage teachings of Rau and Cadillon to reposition the effective pivot of Przybylski's hinged boom.
• Weakness in the record: Przybylski's disclosure is unverified; if it discloses only a single hinged joint without a link, the shift of the pivot forward of the inner section still requires the offset-pivot insight (Marcantonio/Green), which is not in the face-cited set.

Ground 2 — Claims 1 and 7 obvious over Stacey in view of Rau and Cadillon

• Primary: Stacey (US 2,176,731) — multi-section folding mast with inter-section pivot bolts/rods (explicitly disclosing the outer section folding about a pin relative to the inner section).
• Secondary: Rau for the inter-section pivoted arm + lock structure and Cadillon for under-folding and removable joint bolts/lug.
• Rationale: Stacey supplies a strong, verified teaching of the multi-section folding structure of claims 1(a)–(b)/7(a)–(b); Rau supplies a pivoted linkage between the two sections (the structural genus into which the two-leg compound arm fits, absent the specific intermediate-pivot geometry); Cadillon supplies the folding-under and releasable-joint elements. The open issue is again the specific intermediate-pivot location of claims 1(d)/7(e).

Ground 3 — Claim 3 obvious over Grounds 1 or 2

Claim 3 differs from claim 1 only by the openings 17 remote from the intermediate pivot (arm pivot), coaxial when extended, with removable means through them for locking/unlocking. Rau's locking arms with a locking lever and Cadillon's bolted-together jib sections whose bolts are removed to fold squarely teach "removable means … for selectively locking said boom sections… or unlocking said sections to permit folding." A POSITA would combine these with the Ground 1/2 structure to obtain a serviceable transport/fold lock. Claim 3 is the narrowest of the three independents and the weakest to sustain.

Ground 4 — Claims 4 and 5 (holding means = bracket + chain) obvious over Cadillon/Rau

• Cadillon's tie-rods and stays (e.g., 21, 23, 42) and the lug connecting jib section 15 to the mast teach holding a folded section to the mast by an elongated tension member; Rau's spring counter-balance teaches an element that holds/supports the folded upper portion against gravity. Substituting a chain from a mid-section bracket for Cadillon's lug/tie-rod is a predictable mechanical substitution (claim 5).
• Honest flag: the specific bracket‑intermediate‑of‑the‑inner‑section + chain combination is not literally shown in any verified face reference. This ground is the weakest of the set and would likely need an additional reference or a "known boom cradle/sling" showing to be robust.

Ground 5 — Claim 6 (skid on outer tip for ground travel) obvious over Cadillon

Cadillon discloses "A tow-bar with a retractable wheel 54 is attached to the jib tip," used during the very folding/ground-handling sequence that claim 6 addresses. Substituting a plain skid for a wheel/nose piece at the boom tip so the tip "move[s] along the ground during retraction" (the specification's skid 26 and the patent's own receding procedure) is a predictable, if not near-anticipatory, design choice. Claim 6 adds little patentable weight, consistent with the earlier section's note that its dependents are conventional adjuncts.

6. Why a POSITA would have been motivated (the KSR rationale, consolidated)

1. Same field, same problem. Every reference is a folding boom/derrick for transport; each is directed to the same difficulty this patent recites — reducing travel configuration without losing boom length. No field-crossing hurdle.
2. Predictable-result assembly. Stacey (hinge structure) + Rau (pivoted inter-section arm and lock) + Cadillon (under-fold, removable joint members, tip wheel) combine known linkage elements with nothing more than "arranging old elements as the references teach," yielding no unexpected result beyond the mechanical sum of their parts.
3. Known offset-pivot solution. The clearance problem and its pivot-relocation answer were known (Marcantonio US 2,529,454; Green US 3,306,470, per EP 0 794 149 A2) before the 1975 filing. This supplies the missing motivation to move the hinge/pivot outward so the folded section clears the carrier/cab — the stated purpose of the invention.
4. Design-incentive. The patent itself concedes alternative configurations ("fold up and over," or rear-mounted boom), confirming these are design choices within ordinary skill rather than inventive departures.

7. The strongest non-obviousness arguments (counter-analysis you should weigh)

To avoid overstating the § 103 case, note what a patent owner (hypothetically) would argue — and where the grounds are genuinely exposed:

• The "shifting terminus" is counter‑intuitive. A two-bar compound arm chosen so the outer section's rear end moves forward on folding is a non-obvious kinematic result; simple hinge references (Stacey, plain bolted joints) teach a rotation about a fixed interface pivot, not a translation. None of the verified face references expressly discloses a two-leg arm fixed at both ends with an intermediate pivot located forward of the inner section's outer terminus.
• No express recognition of the problem in the face-cited set. The five cited references do not, on the verified disclosures, articulate the specific interference-with-carrier problem or the pivot-relocation cure; that cure appears only in uncited analogous art (Marcantonio/Green), raising a "teaching, suggestion, or motivation" vulnerability unless that analogy is accepted.
• Two references are unverified. Przybylski (US 2,689,656) and Tornborg & Lundberg (SE 301,039 B) could not be read; a final validity opinion cannot rest on them without obtaining their full texts.

On balance, claims 1, 3, and 7 are vulnerable under § 103 on the Grounds 1–3 combinations only if the offset-pivot analogous art (Marcantonio US 2,529,454 / Green US 3,306,470) is admitted and if Przybylski's unretrieved text contributes a hinged-section crane boom. Claims 4–6 are the most vulnerable (Cadillon's tip wheel for claim 6; lug/tie-rod or counter-balance for claims 4–5), consistent with the earlier assessment that the dependents carry little independent weight.

8. Confidence and sourcing notes

• High confidence in the disclosures I quote for Stacey (US 2,176,731), Rau (US 3,034,660), and Cadillon (GB 971,103), drawn from those references' own text/abstracts (2176731; 3034660; GB971103A).
• Low / unverified for US 2,689,656 and SE 301,039 B — I have only bibliographic records, and I have not fabricated any disclosure for them.
• US 2,529,454 (Marcantonio) and US 3,306,470 (Green) are not on the face of US 4,024,957; I cite them only as analogous-art evidence surfaced via EP 0 794 149 A2 (PDF) and label them as such. Do not attribute them to the "Prior Art section" of this page.
• No claim constructions reached here conflict with the previously generated sections of this analysis (bibliographic, litigation, and PTAB sections), which I have treated as authoritative and have not repeated.
• No litigation, PTAB, or CAFC record for this patent exists per the earlier sections; these § 103 grounds are therefore academic/defensive-analysis only, not a deployed invalidity contention.

If you want, I can (1) pull the full texts of US 2,689,656 and SE 301,039 B to close the two verification gaps, and (2) run an element-by-element claim chart for claim 1 against the Ground 1 combination for a formal invalidity-contentions appendix.