US Patent 9649441 Injection device (bayonet cap removal)

An injection device 110 is described having a housing 112 and a housing closure means 130. The injection device 110 houses a syringe 114 having a needle 118 which is sealed by a boot 117. The housing closure means 130 is arranged so that the boot 117 can be connected to the housing closure means 130 simply, but cannot be removed from the housing closure means 130. The housing 112 and housing closure means 130 are arranged so that upon rotation of the housing closure means 130, the housing closure means 130 member first rotates relative to the housing and then moves away from the housing. The injection device is simple to use and manufacture.