An Injection Needle Assembly for an Injection Device and an Injection Device Comprising Such Assembly

An injection needle assembly for an injection device, comprising:

• a needle cannula attached to a needle hub, the needle cannula extending along an axis from the needle hub towards a free end, and
• a flexible needle cover forming an axially extending elongated enclosure accommodating the needle cannula, wherein the needle cover has a needle hub end mounted relative to the needle hub and a free end extending beyond the free end of the needle cannula, the needle cover being configured to axially collapse for being penetrated by the needle cannula when an axially directed penetration force is applied on the free end of the needle cover towards the needle hub, the needle cover defining:
• an elongated shaft section encircling the needle cannula and having a first axial end at the needle hub and a second axial end located axially between the needle hub and the free end of the needle cannula, the shaft section comprising a collapsible wall area that is radially deformable for abutting contact with the needle cannula, the collapsible area comprising an area having wall thickness t1 less than a predefined wall thickness t1,lim, and
• a bulb section connected to the second axial end of the shaft section and extending to a closed end surface at the free end of the needle cover, wherein the bulb section defines a bulb wall area axially overlapping and encircling the free end of the needle cannula wherein the bulb wall area comprises a wall area having wall thickness of at least t2, wherein t2 is greater than said predefined wall thickness ti,lim, and wherein the bulb section defines a central end wall area having a wall thickness t3 smaller than the wall thickness t2,
• wherein the needle cover, in an initial non-penetrated state, assumes a first configuration wherein the wall areas of the bulb section and the wall areas of the shaft section are spaced apart from the needle cannula.