Invalidity dossier
US 515810
Faucet
Added 9/23/2026, 11:04:10 AM
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Patent summary
Title, assignee, inventors, filing/issue dates, abstract, and a plain-language overview of the claims.
Patent Overview: US 515,810 — "Faucet"
Title: Faucet
Patentee: William Wrigley, of Boston, County of Suffolk, Massachusetts (no assignee named in the supplied text)
Patent number: US 515,810
Application filed: April 18, 1892 (Serial No. 429,633; "No model")
Granted/dated: March 6, 1894
Classification (per source): F16K 41/00, 41/10, 41/12 (spindle sealings with flat diaphragm)
Source: https://patents.google.com/patent/[US515810](/patent/US515810)/en
Purpose. The invention is "a self closing faucet," intended to be "simple, efficient, and inexpensive." The valve seats on the water inlet against the pressure of the water and is operated by a stem through a multiple screw thread of steep pitch, with a spring between them biasing the valve toward its seat.
Plain-language scope. Turning the handle rotates the stem; because the valve does not rotate, the steep-pitch screw connection converts that rotation into straight-line (longitudinal) motion of the valve off its seat, compressing the spring. Releasing the handle lets the spring's expansive force reverse the rotation and reseat the valve. A flange on the stem is confined between the faucet neck and a cap, restraining the stem longitudinally; an inclined stem portion (d5) seats in the cap so water pressure jams the tapers together, eliminating packing. The valve's cup-shaped body is held against rotation in the neck (square fit suggested, though the specification says other well-known means suffice). The spring acts by expansion only, not torsion, and compensates for wear.
What the excerpt does not establish. It does not identify an assignee, any ownership transfer, litigation, or validity determination. It also does not state the actual filing/grant dates as anything other than the source's metadata; no claims beyond the single quoted "consisting essentially" clause appear; the full drawing sheets (Figs. 1–3) are referenced but not reproduced. The single "Cited By" entry (US 2,596,419, Mueller Co., 1952) is listed by the source but is not analyzed here, per instruction.
Generated 10/1/2026, 9:54:03 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
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.