Non-Round Reservoir Injection Pen with Telescoping Screws

A delivery pen comprising:

• a reservoir comprising a non-circular shape;
• a plunger positioned in the reservoir;
• and
• a screw mechanism at least partially inserted within the reservoir, the screw mechanism comprising:
• a drive shaft comprising one or more protruding member at a proximal end and an elongated member extending longitudinally from the proximal end;
• an inner screw concentrically engaging the elongated member, the inner screw comprising a wide section and a narrow section extending longitudinally from the wide section;
• an outer screw concentrically engaging the wide section, the outer screw comprising a circular section rotatably engaging the one or more protruding member, and a non-circular section sized to fit within the reservoir;
• and
• a pusher disposed between the narrow section and the outer screw to linearly translate a plunger to dispense a medication from the reservoir.

A delivery pen comprising:

• a main body;
• a cap engaged to the main body;
• a torque coupling component comprising inner axial slots, wherein the torque coupling component is housed with the main body;
• a screw mechanism comprising:
• a drive shaft comprising a proximal end and an elongated member extending distally from the proximal end, wherein the proximal end of the drive shaft comprises one or more protruding member configured to mate with the inner axial slots of the torque coupling component;
• an inner screw concentrically engaging the elongated member and comprising a first outer threading;
• an outer housing comprising a circular section and a non-circular section, wherein a proximal end of the circular section comprises an indent configured to engage the one or more protruding member such that the drive shaft can rotate about but cannot longitudinally extend from the indent;
• and
• a pusher, wherein an inner surface of the pusher comprises inner threading configured to mate with the first outer threading of the inner screw;
• a reservoir housed within the cap, the reservoir comprising a non-circular shape, an outlet port at a distal end, and a plunger movable along a longitudinal axis of the reservoir, the plunger configured to engage a distal end of the pusher and to provide a seal with respect to inner walls of the reservoir to prevent fluid provided in a fluid chamber defined on a first side of the plunger from leaking into a portion of the reservoir defined by a second side of the plunger;
• and
• a dose knob engaged to the torque coupling component, wherein the dose knob is rotatable with respect to the main body for adjusting a volume of fluid delivery such that rotation of the dose knob in a first direction facilitates axial translation of the drive shaft away from a proximal end of the main body, and rotation of the dose knob in a second direction facilitates axial translation of the drive shaft toward the proximal end of the main body.

A delivery pen comprising:

• a non-circular reservoir;
• and
• a screw mechanism at least partially inserted within the non-circular reservoir, the screw mechanism comprising:
• a drive shaft, wherein a proximal end of the drive shaft comprises one or more protruding member;
• an inner screw comprising a wide section and narrow section, wherein an inner surface of the inner screw is keyed to engage a distal end of the drive shaft such that torque applied to the drive shaft is transferred to the inner screw, the wide section comprises a first outer threading, and the narrow section comprises a second outer threading;
• an outer screw comprising a circular section and a non-circular section, wherein the circular section comprises inner threads configured to engage with the first outer threading, and wherein a proximal end of the circular section comprises an indent configured to engage the one or more protruding member such that the drive shaft can rotate about but cannot longitudinally extend from the indent;
• and
• a pusher distally configured to engage a plunger, wherein an inner surface of the pusher comprises inner threading configured to mate with the second outer threading of the inner screw.