What Is US Drug Patent 8,684,969 and What Does It Claim?
US Patent 8,684,969 is directed to a spring-driven injection device with a torsion spring coupled to a dose setting mechanism and a rotatably mounted dose display (dose indicator barrel). The core claim set is built around the mechanical linkage chain that converts user dose selection into (1) torsion spring energy storage, (2) dose ejection via longitudinal piston rod movement, and (3) dose display rotation and return-to-zero during ejection.
The asserted independent claim concepts are repeated across claims 1, 11, and 15, with dependent claims adding features such as ratcheting, locking, release buttons, stop members, linear working range of the torsion spring, and combined translational and rotational motion of a threaded display barrel.
What Is the Claim Scope in Independent Claims?
Claim 1: What elements define the protected injection system?
Independent claim 1 requires, in combination:
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Dose setting and torsion storage
- A torsion spring (12) operatively connected to a dose setting member (1).
- The dose setting member sets the dose to be ejected.
- The torsion spring has a substantially linear working range that corresponds to the operation range of the display member.
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Rotatably mounted display/dose indicator barrel
- A rotatably mounted display member adapted to display the dose in accordance with the dose setting member.
- The display member is rotatable over at least one revolution.
- The rotatably mounted display comprises a dose indicator barrel (9).
- The display member moves between two end positions that define the operation range associated with the torsion spring’s linear working range.
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Piston rod drive chain with threaded mechanics
- A housing (5).
- A piston rod (2) with a threaded outer surface.
- A drive track (7) arranged longitudinally on the piston rod outer surface.
- The dose setting member is rotatably mounted and defines a passage for the piston rod.
- Dose setting member has an inner guiding track (11).
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Rotatable drive member engagement
- A rotatable drive member (6) at least partly engages the piston rod drive track (7) to drive the piston rod.
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Display barrel kinematics tied to housing threads
- The dose indicator barrel has a part engaging at least part of the guiding track (11).
- The dose setting member and dose indicator barrel are movable relative to each other.
- The dose indicator barrel has a threaded outer surface (8) cooperating with a threaded inner portion (10) of the housing.
- Result: upon rotation of the dose setting member, the dose indicator barrel undergoes combined translational and rotational movement relative to the housing.
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Threaded portion links piston rod rotation to longitudinal motion
- Rotation of the piston rod relative to the housing results in longitudinal movement due to a threaded portion (3) cooperating with the piston rod threaded outer surface.
Practical meaning: claim 1 protects a coordinated mechanical system where dose display motion (barrel kinematics and end stops) is linked to the torsion spring working range and where the piston rod converts rotational motion to axial piston stroke using threaded cooperation, while a drive member + track transfers torque.
Claim 11: What is the alternative independent structure?
Independent claim 11 is substantially the same architecture as claim 1 but with some wording differences. Key required elements:
- Torsion spring coupled to dose setting member
- Rotatably mounted display with a dose indicator barrel
- End positions define operation range aligned to the torsion spring’s linear working range
- Housing with threaded inner portion (10)
- Piston rod with threaded outer surface and longitudinal track (7)
- Dose setting member rotatably mounted with passage and inner guiding track (11)
- Rotatable drive member engages track or threaded outer surface to drive piston rod (wording differs from claim 1)
- Dose indicator barrel engages guiding track (11)
- Dose indicator barrel includes threaded outer surface cooperating with housing threads (combined translational + rotational movement)
- Rotational drive member relative to housing drives longitudinal piston movement
Scope effect: claim 11 broadens some interaction descriptions (track vs threaded outer surface engagement language), but still requires the combined translational and rotational display barrel behavior and torsion-linear-range coupling.
Claim 15: What extra architecture is captured?
Independent claim 15 focuses on the energy flow and display motion:
- Housing with threads (10) on inner surface
- Dose setting member rotatably sets dose
- Piston rod has threaded outer surface with track (7)
- Rotatable drive member engages track or piston threaded outer surface to drive piston rod
- Torsion spring operatively connected to dose setting member and housing:
- Energy accumulates in torsion spring upon dose setting member rotation
- Energy release rotates drive member
- Pistion rod moves in distal direction automatically to eject set dose
- Rotatably mounted display member is:
- threadedly engaged with the housing threads (10)
- operatively connected with the dose setting member such that when the dose setting member rotates to set dose, the display member rotates with it and is adapted to display the dose
- display member is axially displaced relative to the housing
- display member returns to zero during ejection
- display member rotatable over at least one revolution
Scope effect: claim 15 is the broadest statement of the display relationship: threaded display engagement + axial displacement + return-to-zero tied to dose setting and ejection.
What Do the Dependent Claims Add (and where are the boundaries)?
Energy transfer and control
- Claim 2: rotatable drive member connected to dose setting member via ratchet (13).
- Claim 3/20: torsion spring arranged between housing and dose setting member so that when dose setting member rotates around piston rod, torsion spring is strained.
- Claim 4/21: torsion spring is helical and extends coaxially with piston rod.
- Claim 5/22: locking member (4) fixates piston rod so no relative rotation between piston rod and housing is possible when locked.
- Claim 6/23: release button releases locking member from locking position.
- Claim 7/24: release button located in distal half of device.
- Claim 8/25: stopping member defines outer position of dose indicator barrel corresponding to maximum obtainable dose.
- Claim 9: dose indicator barrel rotates to a zero position during ejection.
- Claims 10 and 12-14: release button action includes spring-driven ejection and coordinated indicator movement to zero; includes resetting by dialing down dose without expelling medication, then re-ejecting reduced dose.
- Claim 10 is the most explicit about reduction-and-reset workflow.
- Claims 12-14 capture the button causing ejection and barrel rotation toward/into zero.
Display geometry
- Claim 17: dose indicator barrel has numerals arranged along a helical path on outer surface; angle is greater than one revolution; includes release button.
- Claim 16: display barrel end positions define operation range tied to torsion spring linear working range.
Kinematic coupling of display and housing threads
- Claim 1/11/18/26 (core kinematic bundle):
- dose indicator barrel has threaded outer surface that cooperates with housing threaded inner portion (10)
- combined translational + rotational movement relative to housing during dose setting member rotation
- dose indicator barrel engages guiding track on dose setting member enabling movable relation between the parts.
Boundary effect: the strongest claim boundaries are (i) torsion spring linear working range mapped to display end positions, (ii) threaded display barrel + guiding track coupling producing combined translation/rotation, and (iii) return-to-zero during ejection.
Key Claim Feature Matrix: What Must Be Present for Infringement
| Feature cluster |
Claim language anchor |
Appears in independent claims |
Notes for scope |
| Torsion spring drives dose ejection |
torsion spring operatively connected to dose setting member; energy stored and released |
1, 11, 15 |
Dependent claims add coaxial helical form and strain behavior |
| Display linked to dose setting |
rotatable display member displays dose per dose setting member |
1, 11, 15 |
Rotatable over at least one revolution |
| Display ends define torsion linear region |
operation range tied to substantially linear working range of torsion spring |
1, 11, 16 |
Strong mechanical “range mapping” limitation |
| Dose indicator barrel |
display comprises dose indicator barrel |
1, 11, 15 |
Barrel includes kinematic coupling to inner tracks and threads |
| Threaded barrel and housing interplay |
barrel threaded outer surface cooperates with housing threaded inner portion; combined translational and rotational movement |
1, 11, 18, 26 |
Central to mechanical differentiation |
| Piston rod axial movement via threads |
threaded outer surface; threaded portion in housing; rotation yields longitudinal movement |
1, 11, 15 |
Depends on thread mechanics in housing/piston interfaces |
| Drive member and track |
drive track on piston; guiding track on dose setting; drive member engages track |
1, 11, 15 |
Ratchet option in claim 2/19 |
| Locking and release workflow |
locking member fixates piston rod; release button releases lock; barrel moves toward zero on press |
5-7, 6-9, 10, 12-14 |
Controls when torsion energy converts to stroke |
| Stop member for max dose |
stopping member defines outer position equals max dose |
8, 25 |
Limits operational range of barrel travel |
| Return to zero during ejection |
barrel rotates to zero during ejection |
9, 10, 12-14, 15 |
Central “reset” behavior |
| Helical numeral display option |
numerals on helical path; angle > one revolution |
17 |
Likely narrower, ornamental-kinematic limitation |
What Is the Likely Patent Landscape Around This Family?
The claim mechanics point to a crowded design space: dose dialers, spring-driven pen injectors, threaded display sleeves, torsion spring energy storage, and return-to-zero indicators are common across modern autoinjector and pen technology.
From a landscape perspective, US 8,684,969’s likely competitive neighborhood includes patents covering:
- Spring-driven autoinjectors with torsion springs
- Dose setting mechanisms with ratchets
- Display mechanisms that rotate and reset
- Threaded or screw-based indicator barrels linked to dose selection
- Locking and distal release actuation
What differentiates this specific patent is the particular mechanical coupling:
- Torsion spring linear working range mapping to display barrel operation range
- Dose indicator barrel threaded to housing producing combined translational and rotational movement
- Guiding track engagement between dose setting member and indicator barrel
- Return-to-zero explicitly tied to ejection and reset workflow
Those elements set a higher bar than generic “rotating dose display” claims and can narrow infringement to devices sharing this exact kinematic chain.
Scope Triage: Where Competitors Can Design Around
High-risk areas (likely harder to design around)
- Any device that uses a torsion spring linked to a dose dial where the dial/display travel defines a linear working segment of the spring.
- Devices where the dose indicator is a threaded barrel engaged with housing threads and that barrel also undergoes axial translation plus rotation during dose setting.
- Devices whose indicator barrel returns to a defined zero position during ejection through the same mechanical linkage.
Lower-risk areas (easier carve-outs)
- Switching from a threaded translating display barrel to a display that uses rotation only, or uses non-threaded axial displacement, while avoiding combined translation/rotation behavior.
- Eliminating the explicit torsion linear working range mapping by using spring segments with non-linear load-deflection or by decoupling spring strain range from the display’s end-stop mapping.
- Using different indicators (LCD/e-ink) or electromechanical counters not sharing the threaded barrel kinematics.
Claim Redundancy and Drafting Strategy
This patent includes multiple independent claims (1, 11, 15) that repeat most mechanical limitations, which strengthens enforceability against partial-copy designs.
- Claim 1 and 11 center on dose setting member + piston rod + guiding track + threaded indicator barrel kinematics plus torsion linear-range coupling.
- Claim 15 emphasizes threaded engagement of display with housing threads and axial displacement plus return-to-zero during ejection, with the energy path through torsion spring to rotate a drive member and move piston rod distally.
Dependent claims add actuation and user workflow:
- locking/release button location and ratchet interconnection (claims 2, 5-7)
- dose range stops (claim 8)
- re-dosing by dialing down without expelling medication (claim 10)
This structure suggests the inventor expects multiple potential infringement theories: mechanical equivalence in the drive chain, indicator barrel kinematics, and actuation workflow.
Practical Enforceability Read: What a challenger must neutralize
To avoid infringement, a challenger would need to negate at least one of these essential combinations:
- Threaded, translation-rotation display barrel engaged with housing threads and coupled to dose setting via guiding track.
- Torsion spring linear working range mapped to display operation range between two end positions.
- Return-to-zero during ejection with coordinated release and locking workflow.
- Track-and-drive coupling from dose setting member rotation to piston rod longitudinal movement.
If a competing product replaces one of those with a substantially different mechanism (for example, a non-threaded indicator, or a display that moves independently from torsion spring strain mapping), the scope narrows significantly.
Key Takeaways
- US 8,684,969 protects a spring-driven injection device with a torsion spring coupled to a dose setting member and a rotatably mounted dose indicator barrel.
- The strongest scope anchor is the combined translational and rotational motion of a threaded dose indicator barrel engaged with housing threads, plus guiding track coupling to the dose setting member.
- A second major anchor is the torsion spring substantially linear working range mapped to the display’s operation range between two end positions.
- Additional boundaries come from locking/release mechanics, ratchet coupling (optional), stop-to-max-dose, and return-to-zero during ejection/reset workflows.
- Competitive landscape risk is highest for devices that share the same indicator barrel kinematics and torsion-linear-range mapping, not just a generic rotating dose dial.
FAQs
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Does US 8,684,969 require a translating display barrel, or can it be rotational only?
The independent claims require the dose indicator barrel to have a threaded outer surface cooperating with housing threads, producing combined translational and rotational movement relative to the housing, and tied to dose setting member rotation.
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Is a torsion spring mandatory for coverage?
Yes. Independent claims explicitly require a torsion spring operatively connected to the dose setting member, with an operation range linked to the torsion spring’s working range.
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Does the patent cover only maximum-dose display positions?
No. It covers an indicator that moves between two end positions defining an operation range, with an optional stopping member for the maximum obtainable dose.
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Is return-to-zero required?
It is explicitly recited in dependent claims and independently implied via the display behavior across the independent claim set. The claims include barrel rotation to a zero position during ejection and display returning to zero during ejection.
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What design-around element is most likely to matter?
Replacing the threaded barrel translation-rotation display mechanism (and its coupling to the guiding track and housing threads) is the clearest pathway to avoid the core mechanical limitations.
References
[1] United States Patent 8,684,969.
