Patent ID: 8900189

Claim:
A fluid infusion device for delivering a drug into the body of a user, comprising: at least one housing; a reservoir for containing the drug; a plunger for displacing the drug from the reservoir to the user; a drive-screw including a first end and a second end, the first end being configured to operatively connect to the plunger; a driving mechanism comprising at least a motor and one or more gears, wherein the one or more gears include a rotating sleeve configured to engage with the second end of the drive-screw; and a support casing substantially contained within the housing, the casing comprising a tube configured to substantially support the rotating sleeve along at least a substantial portion of a length thereof, and enable substantially free rotation of the rotating sleeve within the tube of the casing; wherein an interior of the support casing comprises at least one pair of substantially flat surfaces positioned adjacent to one another, wherein the surfaces are positioned relative to one another at an angle less than 180 degrees, and a biasing member for biasing the rotating sleeve relative to the at least one pair of substantially flat surfaces.