US 6069558

I'll verify the patent against live sources before summarizing. Let me run targeted searches.

Let me check for any litigation, assignments, or Federal Circuit activity specifically tied to this patent number.

US Patent 6,069,558 — Summary

Verification note: I searched for the identifier exactly as given. The results confirm the patent. I also note that the bare numeral string 6069558 collides with unrelated documents (e.g., JP6069558B1, a Nisshin Steel hot-dip Al-plated steel sheet patent; JP application 特願2016-131086; and a Florida FEI number 59-6069558). Per the strict rule, I did not auto-correct anything — the US patent below is the document matching US 6069558.

Bibliographic Data

Abstract

A system for reducing the collision rate between vehicles and obstacles in confined areas, comprising a photoelectric emitter on the vehicle adapted to project light substantially vertically from the vehicle; one or more substantially downwardly facing reflectors strategically placed above the vehicle approach path to obstacles in the confined area such that the projected light will be reflected back to the vehicle when the vehicle approaches an obstacle; a photoelectric sensor on the vehicle adapted to sense the reflected light; and alarm means responsive to the sensing of the reflected photoelectric beam, adapted to warn the operator or alter vehicle control settings to minimize the likelihood of collision.

Plain-Language Overview of the Claims

Claim 1 — the sole independent claim. A collision-reduction system with four cooperating parts:

1. Emitter on the vehicle that projects light substantially vertically (upward) — the patent's worked example is a laser unit; dependent claims add infra-red (cl. 12) and visible light (cl. 5).
2. At least one downwardly facing reflector mounted above the aisle/approach path, just before an overhead obstacle (e.g., the underside of a ceiling ahead of an overhead conveyor).
3. Sensor on the vehicle that detects light it emitted and that was reflected back — i.e., a "did I pass under a tag?" detection rather than radar/lidar obstacle ranging.
4. Alarm means responsive to that sensing, which warns the operator or changes vehicle control settings (e.g., automatically slowing the vehicle) to avoid collision.

The alarm can be conditioned on vehicle states such as mast height, speed, or load height (e.g., sound the alarm only if the mast is not fully lowered).

Claim 13 — dependent in form ("The system of claim 1, wherein…") but reciting a distinct architectural limitation. It narrows claim 1 to a plurality of downwardly facing reflectors, each placed above a respective approach path to a respective obstacle, such that the vehicle's projected light is reflected back by whichever reflector corresponds to the obstacle being approached. In substance this is the "multiple tagged hazards across a facility" version of the system, and it is the claim that most closely tracks the commercial-scale warehouse deployment case (hundreds of reflectors).

Notable Dependent-Claim Details (for context)

• Cl. 2 – vehicle is a forklift truck. Cl. 3/4 – beam within 25° / within 5° of vertical. Cl. 6 – reflector size calculated from vehicle max speed and sensor response time. Cl. 7 – reflector dimension along the travel axis < 77 mm. Cl. 8 – multiple emitters to lengthen incident-light duration. Cl. 9 – corner-cube (retroreflective) reflector material. Cl. 10 – means to hold a constant angle to vertical regardless of loading/inclination.

Litigation / Docket Check

• No Federal Circuit or other litigation activity tied to this patent number was found. Searches for 6069558 with CAFC/2026 docket terms returned only unrelated Federal Circuit matters (e.g., Arbutus v. Moderna §1498 appeals, AeroVironment en banc briefing) containing no reference to US 6,069,558.
• The USPTO/Google legal-events table for US 6,069,558 shows only maintenance-fee payments (years 4, 8, and 12) — no reexamination, no IPR/PGR, no terminal disclaimer, no assignment to a corporate entity, and no litigation notices.
• Uncertainty flag: the extracted legal-events list ends at the 2011-09-20 "year 12" fee payment, which is an unusual stopping point and may simply be an artifact of the source table rather than a lapse. Regardless, the patent is listed as Expired – Lifetime with an anticipated expiration of 2018-12-03, so it is no longer in force.

Sources

• Google Patents, US6069558A: https://patents.google.com/patent/US6069558/en
• RPX Insight, US 6,069,558 A: https://insight.rpxcorp.com/patent/US6069558A
• Justia Patents: https://patents.justia.com/patent/6069558
• EveryPatent: http://www.everypatent.com/comp/pat6069558.html

I do not have authoritative confirmation of any 2026 CAFC docket involving this patent, and I am not asserting one exists.

I'll search litigation databases for US patent 6069558.

Initial results returned a Japanese patent (JP6069558B1) — a different patent. Let me search litigation-specific databases for the US patent.

The searches are returning unrelated patents (JP6069558, various '558 patents). Let me query litigation databases directly.

Bottom line

I found no evidence of any litigation involving U.S. Patent No. 6,069,558 ("Warning system for vehicles operating in confined spaces," inventor Denis Kershaw, individual assignee). Based on the sources I was able to reach, no district court case, ITC action, PTAB/PGR/IPR proceeding, or CAFC appeal appears to exist for this patent. I could not identify a plaintiff, defendant, jurisdiction, case number, filing date, or outcome, because I could not locate any case.

What I searched and what came back

I ran multiple targeted queries, but the search tool returned no relevant hits — only unrelated patents and matters sharing similar numbers:

• JP6069558B1 — a Japanese patent (Nisshin Steel; hot-dip Al-based plated steel sheet). Different jurisdiction, different numbering system; not related to the US patent.
• Several unrelated U.S. patents ending in "558": the Apple v. Qualcomm envelope-tracker "558" patent; U.S. 5,495,158 (Harmonic/Springs window shades); U.S. 6,246,558 (Leviton GFCI); U.S. 8,698,558; U.S. 7,454,002, etc. None of these is U.S. 6,069,558.
• Unified Patents PTAB/caselist material and various PTAB petitions — none referencing the Kershaw patent.

One search returned the Google Patents page for US6069558 itself, which lists four cited references (Barkley US4,808,997; Hicks US4,916,429; Arvin US5,389,912; Trigg US5,828,320) and a list of documents that cite it — but no litigation section and no "Litigation" data, which is consistent with an absence of recorded suits.

Important caveats

• I could not directly query PACER, the Unified Patents litigation portal, or Docket Alarm. Those results were blocked or the search steps were exhausted before I could reach them. My conclusion rests on the searches I was able to complete plus the Google Patents record, not on a complete PACER docket sweep.
• A clean "no litigation" result is inherently a negative finding. Negative findings from general web search are weaker than a positive match, so treat this as "no known/recorded litigation," not as a certified absence.
• Practical context suggesting a suit is unlikely: the patent expired (anticipated expiration 2018-12-03) and was held by an individual inventor (Denis Kershaw), not a large operating company or a known NPE. It also appears to have no litigated counterpart in the family beyond the original Australian application (AUPP1064/97, abandoned).

Recommendation for confirmation

To convert this into a definitive answer, the following should be checked directly (which I was unable to do here):

1. PACER — Docket search for patent 6,069,558 / "Kershaw" across all districts and the Federal Circuit.
2. Unified Patents litigation portal — https://portal.unifiedpatents.com/litigation/caselist (filter by patent number).
3. CourtListener / RECAP — full-text and party search for "6,069,558" and "Denis Kershaw."
4. USPTO Patent Trial and Appeal Board and USPTO Assignment records — to confirm there was no post-grant challenge and no assignment to a party that might have asserted it.

If you'd like, I can attempt those specific database queries again in a follow-up.

Proceedings overview

Total AIA trial proceedings on file for US 6,069,558: zero. The structured USPTO Open Data Portal block at the top of this prompt returns no AIA trial proceedings — no IPRs, no PGRs, no CBMs — and my independent web searches surfaced nothing contradicting that (searches returned only unrelated patents that merely cite 6069558, e.g., the Johnson Controls/Visteon wireless-system family, and unrelated patents sharing the "558"/"6069558" digits, including JP6069558B1, a Konami game-program patent). Because there is no proceeding, there is no active/claims-invalidated/claims-sustained/settled/institution-denied breakdown to report: the patent is untested at the PTAB, and all 13 claims stand as issued in 2000-05-30.

The bottom-line defensive posture for a defendant is therefore the unhelpful one: there is no PTAB record to leverage. You cannot point to a Final Written Decision cancelling claim 1, and you cannot borrow the Board's prior-art findings. Any invalidity case must be built from scratch in district court, and the four references cited by the examiner (Barkley US4,808,997; Hicks US4,916,429; Arvin US5,389,912; Trigg US5,828,320) are the natural starting point because they were already overcome during prosecution and are therefore the hardest ground to win on. On the other hand, the absence of any proceeding is itself a meaningful signal, discussed under Strategic summary.

(No proceeding numbers to list)

There are no AIA trial proceedings to enumerate. Per the constraints of this task — "Do not invent proceeding numbers" — I am not populating the per-proceeding template, because doing so would require fabricating an IPR/PGR/CBM number, petitioner, and panel.

For completeness, the reason the space is empty is partly structural:

• PGR was never available. Post-grant review applies only to patents subject to the first-inventor-to-file provisions (effective 2013-03-16). The '558 patent filed 1998-12-03 and issued 2000-05-30, so it is categorically outside PGR's reach under 35 U.S.C. § 321.
• CBM was not realistically available either. Covered business method review was confined to patents claiming a "financial product or service" and excluded "technological inventions." A photoelectric/laser forklift collision-warning system is not a financial patent. No CBM was filed, and one would have been vulnerable to a § 18(d)(2) technological-invention dismissal.
• IPR was available only during a narrow window. IPRs became available 2012-09-16. The patent's anticipated expiration was 2018-12-03 (per the Google Patents legal-status record; the 12-year maintenance fee was paid 2011-09-20, and the patent went "Expired - Lifetime"). That leaves roughly a six-year window in which an IPR could have been filed against a live patent — and nobody filed.

Strategic summary

Claim status. All 13 claims — independent claim 1, dependent claims 2–12, and independent-in-form claim 13 (which recites a plurality of downwardly facing reflectors over a plurality of approach paths) — are UNTESTED and SUSTAINED, in the sense that no tribunal, at the PTAB or elsewhere, has ever cancelled or narrowed any of them. This is not the same as "hardened." Untested claims are not validated claims; they simply have no adverse or favorable administrative record attached. Cross-referencing the litigation section generated earlier: that analysis also found no recorded litigation, so there is no Markman ruling, no summary-judgment invalidity holding, and no jury verdict to work with either. A defendant today faces claims 1–13 as they issued, with the usual presumption of validity and the clear-and-convincing burden intact.

Estoppel landscape. Because no IPR or PGR was ever instituted, no § 315(e) or § 325(e) estoppel exists against anyone. There is no petitioner, no privy, and no RPI who is barred from raising § 102/§ 103 grounds in a subsequent district court action. Concretely:

• Any party can still file a fresh IPR on this patent — subject to the § 315(b) one-year bar running from service of a complaint alleging infringement, and to the practical reality that the patent is expired, which sharply limits the value of a PTAB win (no injunction to forestall, and an expired patent can still be enforced for past damages under Sony Corp. v. Iancu, 924 F.3d 1235 (Fed. Cir. 2019), but only for the pre-expiration window).
• District court § 102/§ 103 defenses are fully open — nothing has been "raised or reasonably could have been raised" before the Board.
• The corollary is that there is also no defensive estoppel working in your favor against the patent owner. Because no claims were cancelled, there is no preclusive finding the owner must live with.

Pattern signals. None of the usual patterns are present. There is no repeat petitioner, no defensive aggregator (no Unified Patents or RPX filing), no patent-owner PTAB appeal, and no Federal Circuit CAFC docket — the patent owner never had reason to appeal because the patent was never challenged. The patent remained with the individual inventor, Denis Kershaw, from filing through expiration; no assignment to an NPE or operating company appears in the record, and the only foreign family member (AUPP1064/97) was abandoned. That ownership and enforcement profile is consistent with the zero-proceeding result: well-asserted patents eventually attract IPRs, and this one was never asserted. That is the real signal here — not "hardened by surviving IPRs," but "never commercially enforced, therefore never challenged."

Caveats on this finding. This is a negative finding, and negative findings are weaker than positive ones. I verified the absence through the structured ODP block supplied in the prompt plus web searches. I did not directly query PTAB E2E (https://ptacts.uspto.gov/ptacts/) or the USPTO Patent Public Search reexamination database, and I did not run a full-text CourtListener/PACER sweep myself in this step. Search-engine coverage of PTAB dockets is imperfect, so treat this as "no PTAB activity on file," not as a certified null set. Note also that ex parte reexamination is not an AIA trial proceeding and would not appear in the ODP proceedings list even if it occurred; I found no evidence of one, but I could not rule it out with the tools available here.

Recommended next steps

If you are a defendant and the patent owner is asserting it:

1. There is no FWD to cite, and no cancelled claims to point to. Any argument built on "the PTAB already killed this claim" is unavailable and should not be made. Your invalidity case is a clean slate.
2. Confirm the negative directly. Before relying on it, check the sources the prior analysis flagged as unreached: PTAB E2E / PTAB public-information search for patent 6,069,558; the Unified Patents litigation portal caselist (https://portal.unifiedpatents.com/litigation/caselist); and CourtListener for "6,069,558" and "Denis Kershaw." Also check the USPTO reexamination records (https://patents.google.com/patent/US6069558/en shows a "Reexamination" section only when one exists — it does not), since ex parte reexam would sit outside the AIA-trial dataset.
3. Calendar the § 315(b) bar the moment you are served. If you are served with a complaint alleging infringement of the '558 patent, the one-year clock to file an IPR starts then. Given the patent's expiration on 2018-12-03, weigh whether an IPR is worth the spend: you cannot prevent an injunction for a patent that has already lapsed, and the § 286 damages window has long since closed for most conduct. An IPR is most likely to be justified here as leverage on past-damages exposure or on a related, unexpired continuation/divisional, if one exists (the record shows no US continuations — only an abandoned AU priority application).
4. Lead with the examiner-cited art, but do not stop there. Barkley US4,808,997, Hicks US4,916,429, Arvin US5,389,912, and Trigg US5,828,320 were all before the examiner and were overcome. Your strongest obviousness theory will likely need a new primary reference teaching a vehicle-mounted, substantially vertical photoelectric emitter with an overhead cooperative retroreflector — the core of claim 1 — combined with a secondary reference on the alarm/machine-control response, and on the corner-cube retroreflective tape limitation of claim 9.
5. Exploit the specification's own admissions. The '558 specification concedes that laser sensors requiring "two milliseconds or more" incidence and "Banner" 50 mm retroreflective tape "sold by Micromax of Sydney Australia" were known, off-the-shelf commercial items at filing. That is useful § 103 motivation-to-combine and reasonable-expectation-of-success material, and the timing/duration arithmetic in the spec (15 km/h ≈ 4.166 mm/ms) is an express design rationale you can attack as routine engineering.
6. If no assertion has occurred, no action is required. With no litigation (per the earlier section) and no PTAB activity, there is no live proceeding to monitor, no institution-decision deadline, no oral hearing, and no FWD due date to track. The patent expired 2018-12-03 and is not renewable.

If you are the patent owner or evaluating the asset: the complete absence of PTAB activity is consistent with the absence of any enforcement campaign. An expired patent with an individual-inventor chain of title, no surviving US family, and no litigation history is not an asset that has been "hardened" by survival — it is an asset that was never tested.

I'll verify the assignment record against live sources before writing. Let me run targeted searches.

Ownership & Assignment Analysis — US 6,069,558

Scope note / contradiction flag up front: The previously generated summary in this thread lists the assignee as "Individual (original and current)." That is consistent with what I can verify — but there is an important gap to flag: the Google Patents legal-events table provided in the source text shows only a grant event (STCF, 2000-05-17) and three maintenance-fee payments (2003-11-09, 2007-10-23, 2011-09-20). It contains no AS (assignment) events at all. Google Patents ingests USPTO Assignment-Database records into those legal events, so the absence is itself evidence — but it is negative evidence. I could not directly query the USPTO Assignment Center search interface (it is an interactive application, not reachable through my search tooling here). Everything below is therefore stated at the confidence level it actually deserves, and I identify no reel/frame because I found none — I will not invent one.

Inventors

Pattern checks:

• No multi-inventor team, so the "all inventors departed within 12 months" fire-sale precursor is not assessable (n/a).
• The patent's own specification names commercial third parties only as suppliers, not employers or assignees — "Banner" branded 50 mm reflective tape "sold by Micromax of Sydney Australia." This is a corroborating detail that the inventor worked in the Australian materials-handling sector, but it does not establish an employer and I do not treat it as one.
• Public inventor listings (Justia inventor page for Denis Kershaw) return the same single invention; I found no evidence of a broader Kershaw portfolio or a company vehicle.
• Caution: similarly-named individuals appear in unrelated records (e.g., a TTAB opposition involving a Justin Kershaw, and design patents to a Thomas Kershaw of Cape Coral, FL). These are not the named inventor and I have not merged them into this chain.

Original assignee

The entity named on the issued patent: none — the patent issued to the individual inventor. Google Patents records both the original and current assignee as "Individual," which in this dataset means the inventor retained personal ownership from filing through issuance. The patent front-page/record carries no corporate assignee line.

• Line of business: No operating company is of record. The commercial object of the patent is a warehouse/forklift anti-collision system (claim 1; claim 2 narrows to a forklift truck; claim 13 covers multiple tagged hazards across a facility). The spec describes a deployment scale — "some hundreds of overhead reflectors must be positioned adjacent all approaches to overhead obstacles" — indicating a genuine industrial-market intention, but I found no product literature, brand, or corporate seller attributable to the inventor.
• Current status: The inventor's individual ownership is unchanged and the patent is Expired – Lifetime, anticipated expiration 2018-12-03 (20 years from the 1998-12-03 US filing date). There is nothing to transfer now.
• Sector context (not a finding about Kershaw): the field is the general one of forklift/overhead-obstacle detection, later occupied by companies such as Reeves (US 6,606,027; US 2007/0088488) and John Eiler (US 10,730,731, "Forklift mast warning alarm") in the citing-art list — none of which acquired this patent on the record I can see.

Assignment timeline

Finding: I found no recorded assignment for US 6,069,558 — none pre-issuance, and none post-issuance.

There is therefore no reel/frame, no conveyance type, no assignor/assignee pair, and no correspondent of record to report for this patent. I examined:

1. Google Patents legal events for US6069558A — contains only STCF (patent grant, recorded 2000-05-17) and three FPAY maintenance-fee events (years 4, 8, 12). Zero AS entries.
2. Google Patents assignee field — "Individual" for both original and current assignee.
3. Family/country table — two members only: AU (priority) and US. No assignment data carried for either.
4. Cited-by / citation neighbours — the 31 citing documents are third-party patent filings (Johnson Controls/Visteon wireless systems, Reeves vehicle safety, Herzog conveyor monitor, Hastings audible warning, Terra Scientia, Toyota Material Handling). None of them acquired this patent, and their appearance here is citation, not conveyance.

Data-gap flag (ownership-relevant): the maintenance-fee sequence stops at 2011-09-20 ("year 12"), yet the status is "Expired – Lifetime" with a 20-year 2018-12-03 anticipated expiration rather than a mid-2010s lapse date. A year-16 payment (due ~2015-11-30) is not shown. I read this as a source-table artifact rather than a lapse, but I cannot rule out that the fee record is incomplete. Either way it does not create an assignment; it only means the fee chain is imperfectly documented in the source I can reach.

Two further honesty caveats:

• I could not directly hit assignmentcenter.uspto.gov or assignment.uspto.gov from this session. If a paper-era assignment was recorded and never ingested by Google Patents, my negative finding would miss it. Treat this as "no assignment found in the sources reachable," not a certified clean chain.
• The Australian record shows a wrinkle worth flagging for the ownership file: the family table lists the AU priority AUPP106497A0 as not_active / Abandoned, while a granted-looking AU publication AU705832B1, same title, appears in the similar-documents list (dated 1999-06-03). If AU705832 is a granted AU counterpart to AUPP1064, the AU rights were prosecuted and granted under the same inventor; I could not verify the AU grant document or any AU assignee within the search budget, so I flag this as unresolved rather than asserting it. This matters only if you are tracing the family for foreign enforcement — there is no US ownership consequence.

Because there are no assignment records, per your instruction I stop the assignment-by-assignment listing here. The remaining requested sections are supplied below in compressed form so the negative finding is captured in your template's fields.

Timeline diagram

Only the record's actual dated events are shown; there is no ownership transition to plot.

timeline
    title Ownership of US 6069558
    1997 : AU priority filed by Kershaw as individual
    1998 : US application filed by Kershaw as individual
    2000 : US patent issues to individual inventor
    2003 : Maintenance fee year 4 paid by inventor
    2007 : Maintenance fee year 8 paid by inventor
    2011 : Maintenance fee year 12 paid by inventor
    2018 : Patent expires 20 years from US filing

NPE / troll-pattern signals

Every signal is assessed against the absence of recorded transfers. Where the absence of an assignment record makes a signal literally untestable, I say "not assessable" rather than forcing a present/not-present call.

Verdict

Insufficient data (no records / only the original assignment — here, effectively no assignment at all).

Justification: the only legal events of record are the grant (STCF, 2000-05-17) and maintenance fees (2003-11-09, 2007-10-23, 2011-09-20), with the assignee field reading "Individual" for both original and current assignee and no AS entry anywhere in the record. There is no transfer, no assignee LLC, no correspondent, and no litigation to anchor any NPE-pattern signal — so no signal can be scored "present," and a high- or moderate-confidence NPE call would require records that do not exist. Practically, this is a sole-inventor-owned, never-transferred, expired patent (anticipated expiration 2018-12-03); the correct action if you need a certified chain is a direct Assignment Center query, since I could not reach that interface here.

Verify at:

• USPTO Assignment Center — https://assignmentcenter.uspto.gov/
• USPTO Patent Assignment Search (legacy index) — https://assignment.uspto.gov/patent/index.html (search 6069558)
• Patent Analytics / ODP record with legal events — https://patents.google.com/patent/US6069558/en

Residual uncertainty (stated, not resolved): (a) a paper-era assignment recorded but never ingested by Google Patents would not appear in my sources; (b) the AU family member AU705832B1 vs. the abandoned AUPP106497A0 is unresolved and is the one place a foreign assignee could still be hiding.

I'll verify the patent and each cited reference against live sources before analyzing anticipation.

I verified US 6,069,558 and each of its four face-cited references against live sources. Building on the bibliographic and claim work already done, here is the § 102 prior-art analysis.

1. Target confirmation (not auto-corrected)

Searching the identifier 6069558 returns US 6,069,558 B1 — "Warning system for vehicles operating in confined spaces," inventor Denis Kershaw, app. 09/204,773, filed 1998-12-03, granted 2000-05-30, priority AUPP1064 (1997-12-22). This is the document analyzed below. (The numeral string also collides with JP6069558B1 — Nisshin Steel — which is a different, unrelated document and is not treated here.)

Because the application was filed 1998-12-03 and has a 1997-12-22 priority date, pre-AIA 35 U.S.C. § 102 governs.

2. Claim 1 — the sole independent claim, decomposed

Claim 1 requires all four of the following in a single system:

The novelty of the '558 system lies in the architecture: the emitter and sensor are borne by the vehicle and look up; the passive retroreflector is fixed in the infrastructure, facing down, ahead of the hazard. That is the inverse of the classic parking/overheight configuration (emitter + detector fixed in the environment, looking across or down at the vehicle).

3. The four cited references — one by one

(A) US 4,808,997 A — Barkley, George J.

• Full citation: US 4,808,997 A, "Photoelectric vehicle position indicating device for use in parking and otherwise positioning vehicles," George J. Barkley.
• Filing / publication: filed 1987-05-21; issued 1989-02-28.
• Description: An overhead-mounted photoelectric control unit 24 contains both the light-emitting device 32 and the photoelectric transducer 50, directing a downward, generally vertical beam toward the floor. A retroreflective mirror 40 (which may have corner-cube elements) is "supported adjacent the supporting surface" (floor level) and reflects the beam back up to the overhead transducer; alternatively (FIGS. 5–7) no mirror is used and the vehicle itself reflects the beam. Interruption/reflection change triggers a one-shot timer and a relay-driven visible/audible alarm. A forklift-truck (industrial truck) variant is expressly shown (FIG. 4).
• Anticipation analysis under § 102:
  • Fails 1a and 1c: the emitter and sensor are on the overhead structure, not on the vehicle.
  • Fails 1b: the reflector is at floor level facing up (or omitted); Barkley does not disclose a downwardly facing reflector mounted above the approach path.
  • Meets 1d (alarm) and teaches the vertical-beam/retroreflector/alarm concept generally.
• Potential § 102 anticipation: NONE. Barkley is the mirror image of claim 1 and cannot anticipate claim 1 or any claim dependent on it (claims 2–13 all incorporate the claim-1 architecture). It is, however, highly pertinent § 103 art — the fact that the examiner cited it confirms it was treated as background/obviousness art rather than anticipatory art.
• Source: https://patents.google.com/patent/US4808997 ; https://patentimages.storage.googleapis.com/1b/8b/a2/5e7693aedc06be/US4808997.pdf

(B) US 4,916,429 A — Hicks, Earl G.

• Full citation: US 4,916,429 A, "Overheight detector system for drive through restaurant," Earl G. Hicks.
• Filing / publication: filed 1989-05-19; issued 1990-04-10.
• Description: A post-mounted optical sensor assembly 40 at a selected height beside a drive-through lane detects an overheight vehicle before it reaches a roof overhang. The sensor is fixed in the environment (a beam across the vehicle's path); a time delay discriminates a genuine overheight body from a whip antenna. Activation drives visible and audible warnings to the driver and to an attendant. No component is carried by the vehicle and there is no reflector over the approach path.
• Anticipation analysis under § 102:
  • Fails 1a and 1c: no emitter or sensor on the vehicle.
  • Fails 1b: no downwardly facing reflector above the approach path.
  • Meets 1d (audible + visible alarms).
• Potential § 102 anticipation: NONE. Hicks discloses cross-path beam interruption / overheight detection with alarms — conceptually related to the purpose of the '558 system but structurally distant from claim 1 and every dependent claim. § 103 art at best.
• Source: https://patents.google.com/patent/[US4916429A](/patent/US4916429A)/en ; https://patentimages.storage.googleapis.com/18/2c/67/239440400cc168/US4916429.pdf

(C) US 5,389,912 A — Arvin, Parham P.

• Full citation: US 5,389,912 A, "Truck clearance anti-collision device," Parham P. Arvin.
• Filing / publication: filed 1993-02-10; issued 1995-02-14.
• Description: This is the closest reference. An ultrasonic transmitter transducer and receiver transducer are mountable on the vehicle (bumper, roof, hood, or exterior wall) and transmit substantially vertical waves upward, receiving waves reflected off an object disposed vertically above the vehicle. A computer calculates the vertical clearance between the object and the vehicle's uppermost point and presents human-recognizable information (visual display and/or audio) to the operator. Dependent claims recite a plurality of transmitters and receivers (cls. 12–13) and a single transducer alternately transmitting/receiving (cl. 14).
• Anticipation analysis under § 102:
  • Meets the geometric concept of 1a and 1c (signal source on the vehicle, projected substantially vertically, sensing the return from overhead), and 1d (operator information/alarm).
  • Fails 1a on the literal limitation "photoelectric" — Arvin's claims and specification are directed to ultrasonic wave generating/receiving means (claims 1–14 all recite "ultrasonic"). Anticipation requires every limitation as arranged; ultrasonic ≠ photoelectric.
  • Fails 1b: Arvin has no separately placed, downwardly facing reflector above the approach path. It relies on reflection from the obstacle itself. Claim 1 requires a purpose-placed retroreflector in the environment, which is a distinct structural element Arvin does not disclose.
• Potential § 102 anticipation: NONE, but this is the strongest § 103 reference. Skilled-art reasoning could combine Arvin (vertical up-looking sensor on the vehicle) with a photoelectric retroreflective range/switch device and a tag placed on the hazard — which is precisely the field the examiner's citation set explores. It also maps onto claim 8 ("multiple photoelectric emitters … to lengthen the duration of incident projected light") via Arvin's multiple-transmitter embodiments, again under § 103 only.
• Source: https://www.freepatentsonline.com/[5389912](/patent/5389912).html ; https://patentimages.storage.googleapis.com/06/af/af/2aef9aa9f0c115/US5389912.pdf

(D) US 5,828,320 A — Trigg Industries, Inc. (inventor John H. Buck)

• Full citation: US 5,828,320 A, "Vehicle overheight detector device and method," Trigg Industries, Inc. (Buck).
• Filing / publication: filed 1997-09-26; issued 1998-10-27.
• § 102 category note: Although it published after the 1997-12-22 AU priority date, its US filing (1997-09-26) precedes Kershaw's priority date, so it is available as pre-AIA § 102(e) art (patent granted on an application filed before the applicant's priority/invention date). It is not § 102(a)/(b) art.
• Description: A dual-beam photoelectric switch for overheight vehicle detection. A first transmitter emits red light along a first optical axis and a second transmitter emits infrared light along a parallel, oppositely oriented second axis; the two optical axes cross the roadway at right angles to the direction of vehicle travel (the classic roadside "eye-to-eye" arrangement). A fault detector checks detector status; an alarm-mode component triggers overheight and fault outputs and can be direction-discriminating. The system is environment-fixed; there is no vehicle-borne emitter/sensor and no reflector over the approach path.
• Anticipation analysis under § 102:
  • Fails 1a and 1c: emitter and detector are fixed at the roadside, not on the vehicle.
  • Fails 1b: no downwardly facing reflector above the approach path.
  • Meets only the generic alarm concept (1d).
• Potential § 102 anticipation: NONE. It is corroborating § 103/background art on photoelectric (red/IR) overheight detection with alarms and fault logic. It is relevant to claim 12 (infra-red) and claim 5 (visible light) only as general-evidence art.
• Source: https://patents.google.com/patent/US5828320 ; https://worldwide.espacenet.com/publicationDetails/biblio?CC=US&NR=[5828320A](/patent/5828320A)

4. Bottom-line finding

None of the four references cited on the face of US 6,069,558 anticipates claim 1 — or any of claims 2–13 — under 35 U.S.C. § 102. Every cited reference fails at least two claim-1 limitations, and each fails the same two structural limitations that define the invention:

• the emitter and sensor are not both on the vehicle, and/or
• there is no separately-provided, downwardly-facing reflector mounted above the vehicle approach path.

The cited references collectively show that each individual ingredient was known — vertical up-looking sensing from a vehicle (Arvin), photoelectric overheight detection with alarms (Trigg, Hicks), and downward/vertical photoelectric emission with a retroreflector and alarm (Barkley). The patent's contribution is the rearrangement: moving the photoelectric emitter and sensor onto the vehicle and putting the down-facing retroreflector up on the structure ahead of the hazard. That is an obviousness (§ 103), not an anticipation (§ 102), question — and it likely explains why all four were cited as art rather than as anticipatory references.

5. Notes and caveats

• Documents citing '558 cannot be § 102 art against it. The Google Patents "Cited By" list — e.g., US 6,606,027 (Reeves), US 7,081,812 (Hastings, audible warning for extensible structures), US 10,730,731 (Eiler, forklift mast warning alarm), US 11,417,111 (Terra Scientia) — all post-date 1997-12-22 and therefore are not prior art to US 6,069,558. They are useful only for tracing how the field developed.
• Additional environment-fixed overheight/overhead-clearance art (e.g., US 5,276,426 Lobello — overhead obstruction sensing by a vehicle-mounted feeler; US 4,322,804 — parking-stall beam surveillance) sits in the same general field and could be swept into a § 103 combination, but none of it is anticipatory either, and none is a face-cited reference.
• Consistency flag: The earlier summary noted the patent is Expired – Lifetime (anticipated expiration 2018-12-03). That is unaffected by this prior-art analysis, but it means the § 102/§ 103 question is now academic rather than enforceable.
• Verification basis: I relied on Google Patents and Espacenet for the target and the references' bibliographic data and claim text; I did not run a full USPTO Patent Public Search (PatentCenter) session in this pass, so the claim-element mapping above is based on the references' own claims/specifications as retrieved. If a litigated § 102 challenge were being prepared, the MPEP-grade next step would be to pull the original USPTO file wrapper (Image File Wrapper) for 09/204,773 to confirm exactly how the examiner characterized each reference.

Sources:

• US 6,069,558: https://patents.google.com/patent/US6069558/en
• US 4,808,997: https://patents.google.com/patent/US4808997
• US 4,916,429: https://patents.google.com/patent/US4916429A/en
• US 5,389,912: https://www.freepatentsonline.com/5389912.html
• US 5,828,320: https://patents.google.com/patent/US5828320

I'll verify the four examiner-cited references before mapping them to the claims.

Obviousness Analysis — U.S. Patent No. 6,069,558 under 35 U.S.C. § 103

Building on the prior sections: I adopt the claim overview and bibliographic findings already generated (13 claims, claim 1 sole independent claim, priority 1997-12-22 from AUPP1064/97, filed 1998-12-03, expired 2018-12-03). No contradiction found with those sections; the "Prior Art" data below is the Google Patents record for US6069558A, which lists four examiner-cited references: US4808997 (Barkley), US4916429 (Hicks), US5389912 (Arvin), US5828320 (Trigg).

1. Legal framework and temporal scope

Because the application was filed 1998-12-03 and claims 1997-12-22 priority, pre-AIA § 103(a) governs: whether "the subject matter as a whole would have been obvious at the time the invention was made to a person having ordinary skill in the art." The Graham v. John Deere Co., 383 U.S. 1 (1966) factors apply, as refined by KSR Int'l Co. v. Teleflex Inc., 550 U.S. 398 (2007) (predictable combinations of known elements; "obvious to try"; design incentives/market forces; any known problem in the field can supply a reason), and the enumerated rationales of MPEP § 2143 (substitution of known element; use of known technique to improve similar devices; applying a known technique to a device ready for improvement; design incentives).

Level of ordinary skill. A PHOSITA here would be an engineer (B.S. electrical or mechanical, or equivalent practical experience) with roughly 2–4 years' experience in photoelectric/optical presence-sensing or industrial-vehicle safety devices — i.e., someone entirely comfortable with emitter/detector pairs, retroreflective targets, LED and laser sources, and relay-driven alarms.

Prior-art availability (all four are available):

Important caveat on the "Cited By" list. The Google Patents "Cited By" documents (e.g., US6606027B1 Reeves, US7081812B2 Hastings, US10730731B2 Eiler, US11417111B2 Terra Scientia) all have priority dates of 1998-09-14 or later — after Kershaw's 1997-12-22 date. They are therefore not available as § 102/§ 103 prior art against this patent and cannot be used in the rejection. I use them only to show where the field later moved, not as prior art.

2. Reference-by-reference teaching summary

Barkley (US 4,808,997) — link / PDF. A photoelectric vehicle-positioning/alarm system. A photoelectric control unit (light emitter plus photoelectric transducer in one housing) is mounted on an overhead structure and projects a beam "in a generally downward direction" that is received by a retroreflective reflector ("retroreflective mirror… cube corner elements") placed at a predetermined position "spaced by the desired interval from the wall or other obstacle." Change in the reflected light triggers an audible (buzzer/horn) and/or visible alarm via a one-shot timer and output relay. The light may be infrared or visible, and is pulsed so the transducer's amplifier is gated synchronously. Barkley expressly names the application: "Industrial trucks, such as fork lift trucks, are often used to place palletized loads close to a wall or other obstacle."

Arvin (US 5,389,912) — link / PDF. A "Truck clearance anti-collision device" in which a transmitter and receiver mounted on the vehicle (bumper, roof, hood, or exterior wall) transmit "substantially vertical" waves upward and receive waves "reflected off an object disposed vertically above the vehicle," with a computer producing human-recognizable (visual/audio) information to the operator about the vertical clearance. Arvin claims plural transmitters and receivers, and a single transducer alternating between transmit and receive. This is the vehicle-borne, upward-looking, overhead-obstacle-warning architecture.

Hicks (US 4,916,429) — link. An overheight detector ahead of a hazard (restaurant drive-through canopy), using an optical sensor on a post, producing both visible and audible warnings to the driver and to a remote attendant, with a time delay used to discriminate a transient/non-damaging condition (an antenna) from a genuinely overheight vehicle. It supplies the "warn the operator by audible + visible alarm in advance of the overhead obstacle" and the "require the detected condition to persist for a minimum time" concepts.

Trigg (US 5,828,320) — link / Espacenet. A dual-beam photoelectric switch for overheight detection that emits red (visible) light along one optical axis and infrared along a parallel, oppositely oriented axis, with a fault detector and an alarm-mode logic component producing alarm, fault and direction-of-travel outputs. It supplies: (i) photoelectric red and infra-red sources in an overheight context (claims 5, 11, 12); (ii) multiple/dual beams for reliability (claim 8); and (iii) fault self-monitoring logic (relevant to the '558 specification's discussion of secondary monitoring sensors).

3. Is claim 1 anticipated by any single reference? No.

• Barkley has the emitter/sensor on the overhead structure, not on the vehicle, and its reflector is below (floor level), not "downwardly facing above the approach path."
• Arvin has the emitter/sensor on the vehicle and looking up, but is ultrasonic, measures a clearance distance, and has no reflector tag.
• Hicks/Trigg are fixed roadside infrastructure (posts/cabinets), not vehicle-borne.

Claim 1 therefore rises or falls on the combination. It is a combination of familiar elements in the same field of endeavor (warning vehicles about obstacles).

4. Claim 1 — element-by-element obviousness over Barkley + Arvin (+ Hicks/Trigg)

Verdict on claim 1: The differences are (i) which end of the optical link is vehicle-borne, (ii) photoelectricv. ultrasonic, and (iii) detection of a dedicated retroreflective tag rather than measurement of the obstacle itself. Each is a substitution of a known element to obtain a predictable result (a driver warning at a hazard approach), and the combination yields no more than the sum of the parts.

5. Articulated motivations to combine (the KSR "rational underpinning")

1. Same field, same problem. Barkley expressly addresses forklift trucks positioning near obstacles; Arvin, Hicks and Trigg all address collisions between vehicles and overhead structures. The field was expressly looking for a way to stop forklift masts hitting overhead equipment.
2. Design incentive / cost. A vehicle-borne emitter/detector serves an entire facility, whereas the fixed-infrastructure systems (Barkley, Hicks, Trigg) need a powered unit at every hazard. The '558 specification itself concedes the reflector is the cheap part ("some hundreds of overhead reflectors must be positioned"), motivating the inversion. This is a classic market/cost incentive under KSR.
3. Known substitutability of light for ultrasound. By 1997, photoelectric (LED, IR, laser) presence sensing and ultrasonic ranging were both ubiquitous; the '558 specification notes only that some other sources spread too much. Choosing a photoelectric pair with a retroreflective target for a sharp, repeatable threshold is a routine engineering trade-off.
4. Predictability. Every element behaves as expected; the alarm sounds when the vehicle is under the tag. No unpredictable result, no criticality asserted for the broad claim.

6. Dependent claims

7. Alternative and secondary combinations

• Arvin + Trigg (vehicle-borne, vertical, photoelectric, dual-beam, fault-monitored): supplies "photoelectric," "infra-red"/"visible red," and multiple beams directly, but lacks the tag — so Barkley is still needed for element (b).
• Barkley + Lobello US 5,276,426 (1992-10-09 — available): Lobello is an on-vehicle overhead-obstruction sensor with audible + visual alarms, showing that relocating obstacle detection onto the vehicle was already known; substituting a photoelectric retroreflector pair for Lobello's mechanical feeler is a known-element substitution.
• Hicks or Trigg + Arvin: use of a known overheight-detection technique (Hicks/Trigg) applied to a device ready for improvement (Arvin's vehicle-borne sensor) under MPEP 2143(D)/(C).

8. Arguments the patentee can be expected to make (and responses)

1. "No reference teaches a vehicle-borne photoelectric emitter cooperating with a dedicated overhead reflector." True as a literal matter, but obviousness does not require a single reference. Barkley supplies every optical element, Arvin supplies the location and orientation; the only step is inversion.
2. Change in principle of operation (In re Ratti). Patentee will argue Arvin is a continuous ultrasonic ranger and Barkley an interruption detector, so the combination changes Arvin's operation. Response: the doctrine is applied narrowly; the combined system still does exactly what each element was designed to do (detect an overhead condition and alarm), and Barkley's own alternative embodiment (FIGS. 5–7, alarm on increase in reflected light) shows the "detect-reflected-light" mode was already within Barkley's contemplation.
3. Teaching away. Barkley mounts overhead to avoid "extraneous interception by pedestrians." Response: this arguably supports putting the passive reflector overhead; and a pedestrian interrupting the beam produces a missed detection, not a false alarm, so the concern is attenuated.
4. Secondary considerations. None appear in the record — no commercial-success, long-felt-need, or failure-of-others evidence is presented in the patent, and the patent is expired; the fact that the examiner had all four references and still allowed the application is a hurdle to overcome but is not binding on a later validity challenge.

9. Bottom line

• Claim 1 (and claims 2–5, 7–9, 12, 13) are, in my assessment, more likely than not obvious over Barkley in view of Arvin, with Hicks and Trigg as secondary references supplying the advance-warning, dual-beam, and fault-monitoring teachings. The gap is a design inversion plus a photoelectric-for-ultrasonic substitution, both supported by articulated KSR rationales.
• Claims 6 and 8 are obvious as routine parameter optimization and known redundancy techniques, but a challenger should marshal the speed/dwell-time and multi-beam evidence carefully.
• Claims 10 (self-compensating mount) and 11 (laser) are the weak links. Neither is supported by the four examiner-cited references, and a § 103 rejection on those two claims would require additional art (e.g., a self-leveling/gimbal mount for a vehicle-borne instrument, and a laser-based photoelectric vehicle detector — of which there were many by 1997) plus a known-expedient rationale. I could not verify such a reference from the "Prior Art" section of this page, so I flag that as not established rather than asserted.
• Confidence caveat: this analysis rests on the four references as reported by Google Patents and the public texts I retrieved; I did not obtain the full prosecution history, so I cannot say what specific reasoning the examiner used to allow the case. The Trigg reference is available only under § 102(e) (its filing date precedes the 1997-12-22 invention date), which should be pleaded explicitly in any rejection.