Invalidity dossier
US 321307
Added 9/23/2026, 9:20:15 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 321,307
Title: Ash-Sifter
Patentee: John McAuliffe, of Oswego, New York. One-half assigned to David F. Fitzgibbons, of same place.
Dates: Application filed April 15, 1885; patent granted and published June 30, 1885. Google Patents lists an "anticipated expiration" of June 30, 1902 and current legal status "Expired – Lifetime."
Purpose: The invention is a novel ash-sifter construction that "effectually prevents diffusion of dust, is easily operated, and deposits the ashes and cinders into different receptacles." The case (A) has a removable cover (A) for loading ashes, and stays closed during sifting to contain dust.
Plain-language scope (per the specification and claims): A sieve (S) sits horizontally inside the case, resting at one end on fixed side guides (a) and at the other on blocks (b) carried by a cross-bar (b) on a slide (d). The slide passes through the case end, has perforations engaged by a locking-pin (p) entering an exterior block (h), and secures the sieve support when pushed in. A reciprocating rod (R), pivotally connected to the sieve's central sides and riding in horizontal side guides (c), connects to an exterior lever (l) that shakes the sieve to separate ashes from cinders. The base has a vertical partition (e) with a pivoted apron/chute (O) above it and drawers/slides (f f) on opposite sides. In operation the chute is swung over one drawer to receive siftings; after the ashes are eliminated, it is swung over the other. Withdrawing slide (d) removes the end support, letting the sieve tilt and dump cinders onto slide (f), which can be removed over a coal-hod. A crank (n) allows further tilting/inversion and jarring the sieve against the undersides of guides (a) to knock out ashes, then returning it to horizontal.
Claims: Three claims, all combination claims: (1) case, guides a and c, removable support b, sieve S, and reciprocating rod R; (2) adds slide d and support b; (3) recites the full described ash-sifter including lever l.
What the excerpt does not establish: The optical character recognition is imperfect (e.g., "aShsift-er," "difierent," "MoAULInnn"), and the drawing images are not reproduced, so the exact geometry of parts cannot be verified. The excerpt provides no information on examination history, claim construction, enforceability, or litigation.
Source: https://patents.google.com/patent/[US321307](/patent/US321307)/en
Generated 10/1/2026, 9:54:14 PM
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Litigation summary
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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
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Prior art
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Obviousness
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Extensions
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Derivative works
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