Invalidity dossier
US 3747859
Torch for thermochemical processing of work pieces
Current assignee: Messer Griesheim GmbH
Added 9/21/2026, 1:06:26 PM
Active provider: DeepSeek · deepseek-flash
Patent summary
Title, assignee, inventors, filing/issue dates, abstract, and a plain-language overview of the claims.
Patent Overview — US 3,747,859
Title: Torch for thermochemical processing of work pieces
Inventors: Heinz Gabel; Gerhardt Lange (Frankfurt/Main, Germany)
Assignee: Messer Griesheim GmbH (Frankfurt/Main, Germany)
Priority: 1970-09-19 (German application P 20 46 415.7)
Filed: 1971-09-13 | Granted/Published: 1973-07-24 | Status listed: Expired – Lifetime (anticipated expiration 1990-07-24)
Purpose: To provide a torch enabling higher cutting speeds while maintaining optimum cut-surface quality — specifically cutting-groove follow-up, groove depth, surface evenness, notching edges, and low slag adhesion on the underside of the cut.
Plain-language scope: The torch has at least one channel for the processing (cutting) oxygen and at least one channel for a fuel-gas/heating-oxygen mixture, whether as a single mixture channel or separate component channels. The key feature is a depression at the outlet of the processing-oxygen channel, at an angle of about 90–150°, preferably 120°. High-speed oxygen discharge in the depression creates a vacuum that draws in the fuel-gas mixture (an injection effect), enriching the oxygen jet's jacket, which burns hotter, focuses the jet, and improves performance. Optional features include: a conical form behind the depression (about 6° cone angle); a cylindrical outlet of 0.1–1 mm (preferably 0.3 mm) after the depression; a nozzle body with a slipped-over nozzle cap whose frontal surface is recessed relative to the body's frontal surface (to guard against backfiring); and slits in the body's exterior wall partly covered by the cap. Claim 1 covers the depression and cylindrical outlet; dependent claims add the nozzle cap/body arrangement and partial slit coverage. Ten claims, one drawing figure. The description states suitability for metal thicknesses of 3–100 mm and fuel gases such as acetylene, propane, natural gas, illuminating gas, or methane.
What the excerpt does not establish: The full claim set, prosecution history, the complete table's data, exact figure details, and any citation of prior art beyond the truncated reference list — notably the excerpt's rendering of the depression angle is garbled ("about 90-150"), and no measurements beyond those quoted here are confirmed.
Generated 10/1/2026, 10:00:55 PM
Cases on file (0)
Specific litigation cases in our database that name US patent 3747859. The free-form analysis below may also discuss cases beyond this list.
No cases on file mention this patent. Upload a CSV or add a case manually in Admin → Manage litigation cases.
Litigation summary
Past and pending lawsuits — plaintiffs, defendants, jurisdictions, outcomes, and notable rulings.
Proceedings on file (0)
All PTAB activity →AIA trial proceedings (IPR / PGR / CBM) filed at the USPTO Patent Trial and Appeal Board against this patent. Sourced from the USPTO Open Data Portal and refreshed every six hours; each proceeding number deep-links to the PTAB E2E docket.
No PTAB proceedings on file. This patent has not been challenged via IPR, PGR, or CBM. The absence is itself a signal — well-asserted patents eventually attract IPRs. The LLM analysis below may surface filings the ODP feed hasn’t indexed yet.
PTAB challenges
AIA trial proceedings at the USPTO Patent Trial and Appeal Board — IPR, PGR, and CBM. Petitioners, judge panels, claim-level invalidation outcomes from Final Written Decisions, and Federal Circuit appeals. The single most important defensive datapoint after litigation history.
Assignment history
Inventors, original assignee, and the chain of ownership recorded with the USPTO — including the correspondent attorney who recorded each assignment, since shell-LLC chains often share one repeat-player attorney even when the entity names look unrelated. Surfaces NPE / patent-troll patterns: shell-entity transfers, known asserters in the chain, repeat correspondent fingerprints, pre-litigation assignments, and bankruptcy fire-sales.
Prior art
Earlier patents, publications, and products that may anticipate or render the claims unpatentable.
Obviousness
Combinations of prior art that suggest the claimed invention would have been obvious under 35 U.S.C. § 103.
Extensions
Patent term adjustments, term extensions, continuations, divisionals, family members, and expiration dates.
Derivative works
Defensive disclosure: derivative variations of each claim designed to render future incremental improvements obvious or non-novel.