Invalidity dossier
US 500466
Boiler-flue expander
Added 9/23/2026, 4:53:49 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 500,466
Title: Boiler-flue expander
Inventor: Leopold Biddle, of Raton, Territory of New Mexico
Patent number: US 500,466
Application filed: January 14, 1893 — Serial No. 453,355 (No model)
Granted/Publication date: June 27, 1893
Source: https://patents.google.com/patent/[US500466](/patent/US500466)/en
Purpose: The invention relates to boiler makers' tools and aims to provide "a new and improved roller expander for boiler flues, which is simple and durable in construction, very effective in operation and arranged to reduce the wear and tear of the tool to a minimum."
Plain-language scope: The tool expands boiler flues using rollers driven outward by a tapering spindle. Its casing (A), preferably steel, has a cylindrical body (B) with longitudinal slots (B) holding the rollers (F); an integral apertured end (C); and an integral cylindrical head (D) of larger diameter than the body, forming a shoulder that abuts part of the rollers and prevents the casing from passing into the flue. An apertured cap (E) screws into the head's outer end, abutting the roller ends to hold them in place, take up strain, and prevent the rollers from detaching when the spindle is withdrawn. The spindle (G) passes through apertures (C, E). In a modified form, rollers have annular grooves (F) matching flue-sheet thickness, with rollers tapering one-half the spindle taper, so that a bead can be formed on the inside of the flue sheet.
Claims: Two claims cover (1) the casing with apertured end, open-ended head, and apertured cap screwing in the head to abut and hold the rollers, and (2) the casing comprising a slotted body, integral apertured end, integral larger-diameter head forming a roller-abutting shoulder, and a cap screwing in the head's outer end.
What the excerpt does not establish: No assignee is identified (the record names only the inventor). The provided material contains no information on litigation, ownership transfers, validity, or detailed prior-art analysis, and no legal conclusion about status is made. Classifications listed are B21D39/00, B21D39/08, and B21D39/10 (tube expanders).
Generated 10/1/2026, 9:44:03 PM
Cases on file (0)
Specific litigation cases in our database that name US patent 500466. 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.