United States Patent 5,394,868: Scope, Claim Boundaries, and US Landscape
What does US 5,394,868 claim in functional terms?
US 5,394,868 is a US drug-delivery patent that claims a metered dry-powder dispenser built around a rotatable powder housing and a rotatable metering plate (metering disk) with one and only one receptacle area that selectively connects either to the powder supply or to an inlet conduit aligned to a base conduit for inhalation delivery.
Core functional architecture embedded in the independent claim (Claim 1):
- Powder housing means holds the powdered material supply and includes a first conduit extending through the housing in displaced relation to the powder supply.
- Metering plate means holds the metered amount using only a single receptacle area (one dose cavity) positioned below the supply.
- Relative rotation between powder housing and metering plate is used to selectively place the single receptacle area in fluid communication with:
- the powder supply (fill position), or
- the first conduit (dispense position).
- A base housing means below the metering plate includes a second conduit that aligns with the first conduit in the dispense condition.
- Spring bias presses base and powder housing toward each other to maintain conduit alignment and sealing conditions.
- Mouthpiece means enables inhalation of the metered dose from the single receptacle area through the first conduit and out through the mouthpiece interface.
The claim is not directed to a new drug molecule. It is directed to the mechanical dose-metering and flow path of a dry powder inhaler or insufflator device, with multiple narrowing dependent claims on geometry, gas permeability, moisture barriers, scraping, and rotational control.
What is the hard claim scope of Claim 1 (the enforceable center of gravity)?
Claim 1 defines an integrated system with the following required elements (all are part of the claim):
System elements required by Claim 1
- Powder dispenser comprising:
- Powder housing holding powder supply
- First conduit within powder housing
- Metering plate with only a single receptacle area
- Metering plate positioned below supply
- Rotatability pairing:
- Metering plate and powder housing are rotatable with respect to each other
- The single receptacle area is selectively in fluid communication with either:
- the powder supply, or
- the first conduit
- Base housing and conduit alignment:
- Base housing disposed below metering plate
- Second conduit in alignment with first conduit when receptacle area aligns for dispensing
- Biasing force:
- Spring means biasing base housing and powder housing toward each other
- Mouthpiece flow path:
- Mouthpiece means enables inhalation
- Mouthpiece in fluid communication with the first conduit
- Dose presentation rule:
- In the dispense configuration, the metered amount exits from the single receptacle area through the first conduit in the powder housing.
Claim 1 exclusivity implications
- The phrase “including only a single receptacle area” creates a strong structural limitation:
- A device with multiple metering cavities, multiple dose chambers, or multiple simultaneously addressable receptacles would not fall within the literal boundary of Claim 1 as written.
- The selective fluid communication is created specifically by relative rotation between the powder housing and the metering plate, not by valves or sliding gates (those could exist, but the claim still requires the rotational arrangement as stated).
How do the dependent claims narrow the scope?
Dependent claims 2 through 22 add specific structural or functional constraints. The main narrowing themes are: geometry, dose cavity structure, gas permeability, rotation control, scraping, moisture barrier, and optional manifold/conduit configuration.
Geometry and conduit offset (Claims 2, 19)
- Claim 2: Powder housing is generally cylindrical with a central axis; the first conduit extends axially, radially offset, and parallel to the central axis.
- Claim 19: If a third conduit exists (Claim 18), that third conduit also extends substantially axially, radially offset, parallel to the central axis.
These provisions matter for knockouts in design-around work: a competitor using a centered conduit or a non-axial conduit path could avoid literal coverage of these dependent features.
Metering cavity construction (Claims 3, 5, 12, 13)
Three distinct narrowing sub-classes exist:
-
Claim 3: Single receptacle area formed by a plurality of perforations that retain powder until dispensed.
-
Claims 12 and 13: Single receptacle area formed by a gas-permeable filter, mesh, or perforated plate element (with two placement variants):
- Claim 12: Located at lower portion of an opening in the metering plate; height less than metering plate thickness.
- Claim 13: Gas-permeable element contacts lower surface and covers an opening defining receptacle area.
-
Claim 5: Metering plate comprises a gas-permeable material; single receptacle area comprises a recess in the metering plate.
These dependent claims are likely the most “design actionable,” because they tie coverage to the physics interface between powder cavity and flow: gas permeability and filtering/perforated elements at specific locations.
Metering plate/boundary definitions (Claim 4)
- Claim 4: Metering plate comprises an upper termination of the base housing means.
This links the metering plate physically as part of the base structure.
Rotation control and drive (Claims 6, 7, 8)
- Claim 6: Rotation limiting means limits rotation of powder housing relative to the metering disk to an incremental angle.
- Claim 7: Rotation drive means rotates powder housing relative to metering disk so the first conduit is in fluid communication with the receptacle area in association with movement of mouthpiece to an exposed position.
- Claim 8: Powder housing is bi-directionally rotatable with respect to metering disk between:
- a first position where receptacle area communicates with supply, and
- a second position where it communicates with first conduit.
These dependent elements constrain the control strategy. A system that uses one-direction indexing or uses a different actuation mapping between mouthpiece exposure and conduit alignment could avoid some dependent claim coverage.
Scraping during relative rotation (Claims 9–11, 21–22)
- Claim 9: Scraper means scraping powder into the single receptacle area during relative rotation; scraper is positioned between supply and metering plate.
- Claim 10: Scraper includes a scraper plate with a plurality of holes, interposed between supply and receptacle area.
- Claim 11: Includes means for rotatably fixing scraper plate with the powder housing.
Additional scraper arrangements appear in the optional manifold embodiment:
- Claim 21: Scraper means positioned in the manifold means.
- Claim 22: Scraper plate arranged in manifold means; each scraper plate has a lower edge extending to the lower surface of powder housing means.
These claims are a strong indicator of intended anti-clogging behavior at the fill stage.
Moisture barrier (Claims 16–17)
- Claim 16: Moisture barrier prevents moisture from exhalation passing into the dispenser through mouthpiece.
- Claim 17: Moisture barrier includes a flap pivotally mounted in the mouthpiece only for opening movement during inhalation.
This suggests a specific one-way or inhalation-triggered barrier behavior. Different moisture barrier geometries (membranes, passive diaphragms, labyrinth seals) could be outside literal scope of Claims 16–17.
Rotational mount / axial movement enabling structures (Claims 14–15)
- Claim 14: Cylindrical wall means holding metering plate in rotatable relation to powder housing.
- Claim 15: Securement means rotatably fixing powder housing with base housing while permitting axial movement between them.
This addresses mechanical tolerances and sealing via spring bias and alignment.
Optional third conduit and manifold architecture (Claims 18–22)
- Claim 18: Powder housing further includes a third conduit for holding supply.
- Claim 20: Includes manifold means supplying powdered material from third conduit to the single receptacle area.
- Claims 21–22: Scraping integrated into manifold with specific scraper plate properties and placement.
This set suggests at least two possible internal architectures:
- single conduit/supply path (simpler),
- manifold/conduit-to-receptacle flow path (more complex).
Where does the claim set sit in the dry powder inhaler landscape?
Even without drug-specific composition claims, the patent’s claim set is a recognizable class within dry powder inhaler and insufflator mechanics:
- Dose metering by rotating cavity interface:
- A single dose cavity (“single receptacle area”) is filled and then aligned to an outlet conduit for inhalation.
- Flow management by conduit alignment and mouthpiece interface:
- Base housing second conduit aligns with powder housing first conduit when the cavity is positioned for dispensing.
- Powder movement management:
- Scraping during relative rotation and potential gas-permeable filtering/perforated elements at the cavity interface.
This matters for landscape reading: the primary competitive threat is other devices using rotary dose cavities and gating via alignment rather than valve-switched chambers. Secondary threat is competing designs that include gas-permeable cavity bottoms and moisture barrier flaps at the mouthpiece.
Claim-coverage map: what to target for enforcement vs design-around
Most enforceable (literal) features
- Single receptacle area requirement (Claim 1).
- Relative rotation between powder housing and metering plate to selectively connect the receptacle to either the powder supply or the first conduit.
- Conduit alignment: second conduit aligns with first conduit when receptacle is in dispense alignment.
- Spring bias pressing base housing and powder housing toward each other.
- Mouthpiece in fluid communication with the first conduit and inhalation from the single receptacle area.
Most “surgical” design-around levers
- Replace single receptacle with multiple cavities or multiple receptacle areas (break the literal “only a single receptacle area” limitation).
- Use a different delivery mechanism than relative rotation between powder housing and metering plate to achieve selective communication (while still meeting dose metering, valve-based or slide-based gating could avoid the core mechanism).
- Avoid the claimed conduit geometry if attempting to avoid dependent claims (Claims 2 and 19).
- Use a different cavity bottom concept rather than gas-permeable filter/mesh/perforated plate (Claims 5, 12, 13) or avoid perforated structure (Claim 3).
- Avoid a moisture barrier flap pivotally mounted in the mouthpiece with inhalation-only opening (Claims 16–17).
Patent landscape notes for the US market (what the landscape likely covers)
Based on the claim set, the US landscape relevant to this patent will cluster around:
- Rotary metered-dose dry powder inhalers with dose cavity fill and dispense via alignment.
- Mechanisms for powder mass control (scrapers, perforated cavity bottoms, gas-permeable elements).
- Moisture protection at mouthpiece interfaces to reduce exhaled moisture backflow.
Practically, infringement analysis for 5,394,868 will hinge on whether the accused device:
- has a single dose receptacle cavity per metering event,
- fills and dispenses that cavity via relative rotation and selective fluid communication,
- includes alignment of first and second conduits by rotation indexing,
- and includes the mouthpiece flow interface and spring-biased alignment.
Key Takeaways
- US 5,394,868 claims a rotary dry-powder dispenser with a single receptacle area and a selective fluid communication scheme created by relative rotation between a powder housing and a metering plate.
- Claim 1 defines the enforceable core: conduit alignment, spring bias for alignment/sealing, and inhalation flow from the single receptacle area through the first conduit to the mouthpiece.
- Dependent claims tighten scope around geometry, gas-permeable/perforated cavity structures, rotation indexing and drive mapping, scraping during relative rotation, moisture barrier flap at mouthpiece, and an optional third conduit plus manifold feed.
FAQs
How many dose cavities does the patent require to infringe Claim 1?
Claim 1 requires “only a single receptacle area” for the metered amount.
Does the patent claim a specific drug compound?
The claim text provided is for a dispenser device structure (metering, conduit alignment, mouthpiece flow), not a drug composition.
What mechanism creates the selective connection between supply and outlet?
The patent uses relative rotation between the powder housing and the metering plate to place the single receptacle area in fluid communication with the powder supply or the first conduit.
Are gas-permeable filters required for Claim 1?
No. Gas-permeable filter/mesh/perforated plate limitations appear only in dependent claims (not in Claim 1 as given).
What is the role of spring means in the claim?
Spring means bias the base housing and powder housing toward each other to maintain alignment, including alignment of conduits when the receptacle area is positioned for dispensing.
References
[1] US Patent No. 5,394,868 (claims as provided in prompt).
