Drive mechanism for positive displacement pumps

A pump mechanism comprising:

• a reservoir comprising a tube-like structure having a first end and a second end, the second end configured with a fluid path;
• a plunger, disposed in the reservoir, the plunger configured to translate longitudinally within the reservoir toward the second end;
• a drive mechanism;
• and
• a linkage between the drive mechanism and the plunger;
• wherein the drive mechanism comprises:
• a slider element, the slider element being generally cylindrical in shape and having a channel defined on a circumferential surface thereof;
• a header element disposed coaxial with the slider element;
• and
• one or more interface elements extending into the channel, wherein the channel defines a zig-zag-shaped track therein such that longitudinal motion of the header element along a longitudinal axis thereof with respect to the slider element causes the one or more interface elements to move through the channel, thereby causing an angular displacement of the slider element with respect to the header element.

A drug delivery pump comprising:

• a reservoir configured to house a drug;
• a needle or cannula configured to penetrate skin of a user;
• a plunger, disposed in the reservoir and configured to translate longitudinally within the reservoir to cause a volume of the drug to be delivered through the needle or cannula;
• a drive mechanism comprising a slider element;
• and
• a linkage between the drive mechanism and the plunger,
• wherein the drive mechanism is configured to deliver a first volume of drug when the slider element is moved in a first direction and a second volume of drug different from the first volume when the slider element is moved in a second direction opposite to the first direction.