An injection device for injection of a medicament from a medicament cartridge is disclosed. The injection device includes a main housing, a piston and an end stop switch in which access to the main body for replacement of the medicament cartridge may only be obtained when the piston trips the end stop...http://www.google.ca/patents/US6997906?utm_source=gb-gplus-sharePatent US6997906 - Injection device with replacement cartridge
