Invalidity dossier
US 376858
Added 9/23/2026, 4:46:12 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 376,858
Title: Thread-holder for spools
Patentee: Ernest C. Cone, of East Hampton, Connecticut (the source lists no assignee)
Dates: Application filed April 4, 1888; Letters Patent dated January 24, 1888 (as printed in the source); anticipated expiration January 24, 1905. Legal status listed as expired.
Purpose: The invention addresses a known problem in preparing thread or filaments for sale. The customary practice was to fasten off the thread by catching its end in a slit or nick cut into the corner or edge of the spool. That nick "becomes useless by the chipping off of the wood," and a "great waste" of thread resulted when the user failed to fasten the end after using a piece from the spool. The object is therefore to provide a spool with improved means for holding the thread end so as to prevent it from unwinding.
Plain-language scope: The improvement is a spool with a radial slit (a cutter socket) cut across one end face. A holder made from a single L-shaped strip of flat sheet metal is driven edgewise into that slit. One prong (the stem or body, c′) seats and is held in the slit; the other prong forms a flat jaw (c²) that lies flatwise along the periphery of the spool head, catching the thread beneath it to prevent unwinding. The holder may be covered by the label usually pasted on the spool end, and the outer edge of the jaw serves as a convenient cutter for severing the thread. It is stated to suit spools generally, and is particularly intended for cotton, linen, or silk filaments, cord, yarn, or worsted.
Claim: The single claim covers the combination of a spool having a slit in one face forming a cutter socket with a cutter made of a single L-shaped piece of sheet metal, one prong seated and held in the slit and the other forming a flat jaw lying upon the periphery of the spool-head.
Source: https://patents.google.com/patent/[US376858](/patent/US376858)/en
What the excerpt does not establish: It provides no information on litigation, ownership transfers, validity, or examination against prior art; the filing date (April 4, 1888) also postdates the printed grant date, an inconsistency the excerpt does not explain.
Generated 10/1/2026, 9:44:12 PM
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Litigation summary
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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
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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.