A PISTON WASHER FOR A DRUG DELIVERY DEVICE AND DRUG DELIVERY DEVICE INCORPORATING SUCH PISTON WASHER

摘要

The present invention relates to a piston washer (109, 209) for use in a drug delivery device for transferring a distally directed axial force from a piston rod (107, 207) towards a piston (199, 299) of a held cartridge (189, 289). The piston washer (109, 209) defines a proximal surface portion (109a) adapted for engagement with the distal portion of a piston rod (107, 207) and a distal surface portion (109b) configured to engage and abut a piston (199, 299). An axial distance defining device (19a1, 109b1, 109c, 209c) is positioned between the proximal surface portion (109a) and the distal surface portion (109b), wherein the axial distance defining device (19a1, 109b1, 109c, 209c) is configured to be shifted from a first axial compressible state into a second axial non-compressible state. The invention further relates to a drug delivery device incorporating such piston washer (109, 209).