Infusion medium delivery device and method with drive device for driving plunger in reservoir

A method of making a delivery device for delivering an infusion medium to a user, the method comprising:

• providing a first housing portion adapted to be secured to a user;
• providing a second housing portion configured to be selectively engaged with and disengaged from the first housing portion to allow disposal of the first housing portion without disposing of the second housing portion;
• supporting a reservoir on the first housing portion, the reservoir having an interior for containing a fluidic medium;
• arranging a plunger within the interior of the reservoir and moveable along an axial direction of the reservoir;
• supporting a slide member on the second housing portion in a position at which an end of the slide member engages the plunger when the disposable housing portion and durable housing portion are engaged, the slide member further having an engagement surface for contacting and engaging a drive surface of a piezoelectric stack drive device;
• supporting a shaft on the durable housing portion in a position at which the shaft extends along the engagement surface of the slide member;
• and
• supporting a piezoelectric stack drive device on the shaft in a position between the the engagement surface of the slide member and the shaft to selectively move the slide member in the axial direction of the reservoir when the second housing portion and the first housing portion are engaged;
• wherein movement of the slide member by operation of the piezoelectric stack drive device is transferred to movement of the plunger in the axial direction of the reservoir, when the slide member is engaged with the plunger.