Medicament delivery devices

1. A medicament delivery device for delivering a medicament to a patient, wherein the medicament delivery device comprises:

a housing;

a holder within the housing for receiving and enclosing a medicament cartridge, where the holder is configured as a door that pivots from an open position to a closed position and is not detachable from the housing;

a piston rod having a distal end for driving a bung of the medicament cartridge;

a drive mechanism including a motor for providing an output drive to the piston rod for delivering the medicament;

a control means for controlling operation of the device;

a bung sensor provided at the distal end of the piston rod for sensing when the piston rod is in contact with the bung;

a latch sensor configured to engage a stop on the holder and to sense whether the holder is in the closed position or the open position, where the stop is located at an end of an arm connected to the holder, where the stop is configured to limit outward pivoting of the holder when in the open position; and

a cartridge sensor configured to sense when a medicament cartridge is in the holder;

wherein the control means is operative for advancing the drive of the piston rod towards the bung when the latch sensor senses the holder is in the closed position and the cartridge sensor senses the presence of a medicament cartridge is in the holder.

2. A medicament delivery device according to claim 1 , wherein the control means is operative for advancing the drive of the piston rod until the bung sensor senses that the piston rod is in contact with the bung.

3. A medicament delivery device according to claim 1 , wherein the control means is operative to stop further advancement of the piston rod: a) when the bung sensor senses that the piston rod is in contact with the bung; or b) when the cartridge has moved to a seated position within the housing after initial contact between the piston rod and the bung.

4. A medicament delivery device according to claim 1 , wherein the housing includes a receptacle for a user replaceable medicament cartridge.

5. An auto-injector including a medicament delivery device according to claim 1 .

6. A medicament delivery device according to claim 1 , wherein the control means is operative to backwind the piston rod by a predetermined amount when the bung sensor senses that the piston rod is in contact with the bung.

7. A medicament delivery device according to claim 1 , wherein the control means only monitors the state of the cartridge sensor after the latch sensor has been activated.

8. A medicament delivery device for delivering a medicament to a patient, wherein the medicament delivery device comprises:

a housing;

a holder within the housing for receiving and enclosing a medicament cartridge, where the holder is configured as a door that pivots from an open position to a closed position and is not detachable from the housing;

a piston rod having a distal end for driving a bung of the medicament cartridge;

a drive mechanism including a motor for providing an output drive to the piston rod for delivering the medicament;

a control means for controlling operation of the device;

a bung sensor provided at the distal end of the piston rod for sensing when the piston rod is in contact with the bung; and

a latch sensor configured to engage a stop on the holder and to sense whether the holder is in the closed position or the open position, where the stop is located at an end of an arm connected to the holder, where the stop is configured to limit outward pivoting of the holder when in the open position;

wherein the latch sensor and the bung sensor are configured to each generate a sensor signal when the door is closed, where the sensor signals are combined so that the resultant combined signal when sent to the control means indicates that the cartridge is present and/or in the correct position when the piston rod contacts the cartridge bung.