Invalidity dossier
US 1081863
Added 9/23/2026, 11:54:14 PM
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Patent summary
Title, assignee, inventors, filing/issue dates, abstract, and a plain-language overview of the claims.
Patent Overview — US 1,081,863
Title: Door for Silos
Inventor: Charles J. Perkins, of Manitou, Colorado
Assignee/ownership (per source): Original assignee listed as James F. Holden and John T. M. Johnston; the specification states the inventor assigned one-third to John T. M. Johnston and one-third to James F. Holden, both of Kansas City, Missouri. Google's "current assignee" listing (JAMES F HOLDEN; JOHN T M JOHNSTON) is expressly described in the source as possibly inaccurate.
Dates: Application filed March 3, 1913 (Serial No. 751,955); patent granted and published December 16, 1913. The source lists this filing date as the priority date, noting that the priority date is an assumption and not a legal conclusion. Legal status shown: expired (anticipated expiration December 16, 1930).
Purpose: To provide a silo door structure that is durable and economical, able to withstand weather and fire, and efficient in use.
Plain-language scope (from the three claims):
- A silo with a lateral wall having a vertical doorway, crossed at intervals by transverse members, plus reinforcing bands that encircle the silo and bear against the outer sides of those members, which have lengthwise recesses to receive the bands.
- Adds sealing material placed in those recesses over the bands, completely enclosing them.
- Adds a plastic (e.g., concrete/cement) wall and plastic transverse members, plastic sealing material, and door sections fitting between the transverse members against their inner sides and the doorway edges.
The description adds that door sections have beveled edges engaging beveled cross-piece edges, so they resist outward displacement but can be removed from inside, successively, as ensilage is emptied; each cross piece serves as a sill, cap stone, and possibly a climbing rung. The wall construction is described as subject matter of a copending application, Serial No. 751,950, also filed March 3, 1913.
Not established by this excerpt: the full drawings' content; the text of the copending application; the referenced reinforcing bars 9 (badly OCR'd as "5)"; whether any claims were amended, rejected, or litigated; and complete bibliographic/legal accuracy of the Google Patents listings.
Generated 10/1/2026, 9:32:12 PM
Cases on file (0)
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Litigation summary
Past and pending lawsuits — plaintiffs, defendants, jurisdictions, outcomes, and notable rulings.
Proceedings on file (0)
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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.