CROSS REFERENCE TO RELATED APPLICATIONS

The present application is a U.S. National Phase Application pursuant to 35 U.S.C. § 371 of International Application No. PCT/EP2017/051202 filed Jan. 20, 2017, which claims priority to Swedish Patent Application No. 1650246-0 filed Feb. 24, 2016. The entire disclosure contents of these applications are hereby incorporated by reference into the present application.

TECHNICAL FIELD

The present disclosure generally relates to medical devices. In particular, it relates to medicament delivery devices.

BACKGROUND

Some medicament delivery devices have a medicament delivery member cover which by movement, e.g. linear displacement, activates medicament expulsion. An example of such a medicament delivery device is disclosed in US2014/0148763 A1.

The injection device disclosed in US2014/0148763 A1 is activated by linear displacement of a needle shield sleeve. The needle shield sleeve is displaceable between an extended position and a retracted position relative to the housing of the injection device. Moreover, the needle shield sleeve is biased towards the extended position so that prior to medicament expulsion, the needle shield sleeve is in the extended position. Linear motion of the needle shield sleeve in the distal direction, i.e. towards its retracted position, is transformed to rotational motion of a container driver locking means which due to rotation releases a medicament container holder, enabling medicament expulsion therefrom.

For medicament delivery devices of this type, medicament delivery could potentially accidentally be activated if the device is subjected to mechanical shock, for example if the medicament delivery device is dropped and hits a hard support surface. This may especially be a risk in case the medicament delivery device has an essentially vertical orientation upon impact. Accidental activation could thus be effected in case the needle shield sleeve due to mechanical shock is displaced linearly thereby rotating the container driver locking means.

SUMMARY

A general object of the present disclosure is to provide a safety mechanism for a medicament delivery device, and a medicament delivery device comprising such safety mechanism, which solves or at least mitigates the above-mentioned problem of the prior art.

There is hence according to a first aspect of the present disclosure provided a safety mechanism for a medicament delivery device for preventing activation thereof in the event of mechanical shock, which safety mechanism comprises a medicament delivery member sleeve, a proximal flange provided at the proximal end of the medicament delivery member sleeve, which proximal flange has a first radially flexible arm extending longitudinally in the distal direction, a housing having a central proximal opening arranged to receive a distal portion of the medicament delivery member sleeve, wherein the medicament delivery member sleeve is axially displaceable inside the housing from an extended position to a retracted position relative to the housing, and a cover having a distal opening forming a channel arranged to receive the medicament delivery member sleeve and the housing, wherein the housing has a proximal portion arranged between the first radially flexible arm and the outer surface of the medicament delivery member sleeve when the medicament delivery member sleeve is displaced from the extended position towards the retracted position, and wherein the channel is dimensioned such that, when the housing is received by the cover, there is a radial distance between the inner surface of the cover and the outer surface of the proximal portion which is less than a radial dimension of the first radially flexible arm, preventing the medicament delivery member sleeve from obtaining its retracted position.

Due to there being a radial distance between the inner surface of the cover and the outer surface of the proximal portion, which is less than a radial dimension of the first radially flexible arm, the first radially flexible arm will not be able to reach its retracted position for activating medicament expulsion, in the event of mechanical shock/impact with a force directed generally in the axial direction.

According to one embodiment, in the distal direction the radial distance between the inner surface of the cover and the outer surface of the proximal portion decreases from initially being greater than a radial dimension of a distal end of the first radially flexible arm. Hereto, the first radially flexible arm may be able to slide axially, when the cover is mounted, until the distance between the inner surface of the cover and the outer surface of the housing is too narrow to allow axial movement of the first radially flexible arm. The distal portion of the first radially flexible arm will thereby successively during distal movement be squeezed between the inner surface of the cover and the outer surface of the proximal portion. Shock absorption may thereby be provided. This may reduce the impact of mechanical shock and protect the mechanical components inside a medicament delivery device provided with the safety mechanism.

According to one embodiment the first radially flexible arm is arranged to bear against the outer surface of the proximal portion in the retracted position.

According to one embodiment the proximal flange has a body, wherein the first radially flexible arm extends from the body, from a radial distance corresponding to the radial dimension of the outer surface of that portion of the proximal end of the housing which is axially aligned with the first radially flexible arm.

According to one embodiment the first radially flexible arm is inclined relative to the central axis of the medicament delivery member sleeve.

According to one embodiment the radial distance to the first radially flexible arm increases in the distal direction.

According to one embodiment the proximal flange has a second radially flexible arm extending longitudinally in the distal direction, and wherein the proximal portion is arranged between the second radially flexible arm and the outer surface of the medicament delivery member sleeve when the medicament delivery member sleeve is displaced from the extended position towards the retracted position.

According to one embodiment the first radially flexible arm and the second radially flexible arm are arranged in a common plane parallel with the longitudinal axis of the medicament delivery member sleeve.

According to one embodiment the second radially flexible arm is arranged to bear against the outer surface of the proximal portion in the retracted position.

According to one embodiment the proximal flange has a body, wherein the second radially flexible arm extends from the body, from a radial distance corresponding to the radial dimension of the outer surface of that portion of the proximal end of the housing which is axially aligned with the second radially flexible arm.

According to one embodiment the second radially flexible arm is inclined relative to the central axis of the medicament delivery member sleeve.

According to one embodiment the radial distance to the second radially flexible arm increases in the distal direction.

According to one embodiment the first radially flexible arm and the second radially flexible arm each extend at least two thirds of the distance from the proximal flange to the proximal end of the housing in the extended position of the medicament delivery member sleeve.

According to one embodiment the channel is dimensioned such that there is a distance between the inner surface of the cover and the outer surface of the proximal portion which is less than a radial dimension of the second radially flexible arm.

According to a second aspect of the present disclosure there is provided a medicament delivery device comprising a safety mechanism according to the first aspect.

Generally, all terms used in the claims are to be interpreted according to their ordinary meaning in the technical field, unless explicitly defined otherwise herein. All references to “a/an/the element, apparatus, component, means, etc. are to be interpreted openly as referring to at least one instance of the element, apparatus, component, means, etc., unless explicitly stated otherwise.

