Rotational metering pump for insulin patch

A rotational metering pump comprising:

• a manifold comprising a reservoir port in fluid communication with a fluid reservoir and a cannula port in fluid communication with a cannula;
• a sleeve comprising a side hole, the sleeve adapted to rotate axially within the manifold between a first orientation with said side hole aligned with the reservoir port and a second orientation with said side hole aligned with the cannula port, the sleeve further comprising a helical groove having a first end and a second end;
• a plunger comprising an overmolded seal molded over a plunger head adapted to rotate and translate axially within the sleeve, wherein axial translation of the plunger within the sleeve changes a pump volume, the pump volume being in fluid communication with the side hole of the sleeve, the plunger further comprising a coupling member adapted to move within the helical groove and between the first end and the second end of the helical groove to cause the plunger to translate axially within the sleeve as the plunger is rotated;
• a motor adapted to rotate the plunger in a first direction causing the pump volume to increase when the sleeve is in the first orientation, and to rotate the sleeve and plunger together when the coupling member reaches the first end of the helical groove, such that the sleeve moves into the second orientation;
• further comprising a rotational limit switch, the rotational limit switch causing the motor to reverse direction after the sleeve rotates to orient the side hole with the cannula port;
• wherein the sleeve comprises an actuator arm fixed to the sleeve that moves a limit switch as the sleeve rotates in either direction, and wherein the limit switch is biased to return to a center position when the actuator arm rotates past the limit switch.