Administration assembly for a medicament delivery device and a medicament delivery device comprising the same
Inventors
André, Erika • Odelberg, Linda • Holmqvist, Anders • Leander, Pär
Assignees
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Publication Number
US-12311155-B2
Publication Date
2025-05-27
Expiration Date
Abstract
An administration assembly for a medicament delivery device is presented having a plunger rod, a plunger rod holder and an activation sleeve configured to receive a portion of the plunger rod holder. The triggering member is configured to move the activation sleeve from a first position to a second position relative to the plunger rod holder. The plunger rod is configured to be axially locked relative to the plunger rod holder when the activation sleeve is in the first position. The plunger rod is released from being axially locked when the activation sleeve is moved towards the second position.
Core Innovation
The described invention is an activation mechanism for a medicament delivery device that includes a housing and a plunger rod having a first axial position and a second axial position. Activation of the medicament delivery device causes the plunger rod to move relative to the housing from the first axial position to the second axial position. A first resilient member is operatively engaged with the plunger rod to exert a biasing force on the plunger rod in a proximal direction during the activation.
An end cap is rotationally and axially fixed to the housing throughout the duration of activation. A plunger rod holder includes a first hold and release structure that is releasably engaged with a second hold and release structure on the plunger rod when the plunger rod is in the first axial position. The biased plunger rod exerts a radial biasing force on the first hold and release structure, and the plunger rod holder is rotationally and axially fixed to the end cap throughout the duration of activation.
An activation sleeve is slidably positioned relative to and partially surrounding the first hold and release structure. Axial movement of the activation sleeve from a first position to a second position causes disengagement of the first hold and release structure from the second hold and release structure. When the activation sleeve is in the first position, it maintains the engagement of the first and second hold and release structures to lock the plunger rod axially relative to the plunger rod holder, and disengagement is caused by proximal biasing of the plunger rod that causes the second hold and release structure to act with a proximally directed force on the first hold and release structure such that the first hold and release structure moves radially outwards to unlock the plunger rod so it can move to the second axial position.
The disclosed embodiments include radially flexible holder arms that are prevented from flexing in the first position by an inner surface of the activation sleeve and are allowed to flex when a distal portion of the sleeve clears. Alternative interlock embodiments include openings and engaging gripping members, and other embodiments use bevelled and cooperating surfaces and protrusion geometry to facilitate disengagement as the sleeve passes an activation line. The disclosure also describes a delivery-member-cover triggering arrangement and optional proximal biasing of the activation sleeve by a second resilient member.
Claims Coverage
Independent claim clm-00001 defines an activation mechanism with an axially movable activation sleeve that maintains an axially locked hold-and-release interface and then disengages it to permit proximal bias-driven release; dependent claims clm-00010 through clm-00020 refine hold-and-release geometry, positional relationships, sleeve dimensions, and include delivery member cover driving the sleeve. The partial content provided contains only one independent claim explicitly.
Activation sleeve-maintained axially locked hold-and-release interface
An activation sleeve slidably positioned relative to and partially surrounding a first hold and release structure where axial movement of the activation sleeve from a first position to a second position causes disengagement of the first hold and release structure from a second hold and release structure, while the activation sleeve in the first position maintains engagement to lock the plunger rod axially relative to a plunger rod holder.
Proximal biasing-driven radial unlock of the hold-and-release structures
Disengagement of the first hold and release structure from the second hold and release structure is caused by proximal biasing of the plunger rod such that the second hold and release structure acts with a proximally directed force on the first hold and release structure, moving the first hold and release structure radially outwards to unlock the plunger rod from the first axial position so it can move to the second axial position.
Rotationally and axially fixed holder and end cap during activation
An end cap is rotationally and axially fixed to a housing throughout the duration of activation, and the plunger rod holder is rotationally and axially fixed to the end cap throughout the duration of activation.
Releasably engaged hold-and-release structures between plunger and holder
A plunger rod holder includes a first hold and release structure releasably engaged with a second hold and release structure on the plunger rod when the plunger rod is in the first axial position, where the biased plunger rod exerts a radial biasing force on the first hold and release structure.
Delivery member cover drives sleeve from first to second position
A delivery member cover is configured to move an activation sleeve from a first position toward a second position.
Radially outward surface engagement and flexing arms for disengagement
A second hold and release structure has first and second radially outwards extending surfaces that are engaged by radially inward portions of first and second arms in a first sleeve position, and moving the activation sleeve to a second position flexes the arms radially outwards to disengage from the radially outwards extending surfaces.
Cooperating beveled surfaces on radially inward portions
First and second radially inwards extending portions have proximal faces that mate with cooperating beveled surfaces.
Activation sleeve first and second inside diameters
The activation sleeve has a first inside diameter and a second inside diameter.
First inside diameter smaller than second and abutting in first position
The first inside diameter is smaller than the second inside diameter, and when in the first position the first inside diameter abuts the first hold and release structure.
Across the provided partial claim set, the inventive concepts center on an activation sleeve that keeps a hold-and-release interlock engaged to lock the plunger rod axially in a first sleeve position, then disengages the interface in a second sleeve position so that proximal biasing drives a radially outward movement of the first hold and release structure to unlock axial movement of the plunger rod.
Stated Advantages
Documented Applications
No documented applications found
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