US 10,376,647 B2
Anti-rotation mechanism for telescopic screw assembly
Jason W. Farris, Gilbert, AZ (US); Jorge Santos, Scottsdale, AZ (US); and Tommy Gene Davis, Athens, TX (US)
Assigned to West Pharma. Services IL, Ltd., Ra'anana (IL)
Filed by MEDIMOP Medical Projects Ltd., Ra'anana (IL)
Filed on Mar. 18, 2016, as Appl. No. 15/74,412.
Prior Publication US 2017/0266385 A1, Sep. 21, 2017
Int. Cl. A61M 5/315 (2006.01); F16H 25/20 (2006.01)
CPC A61M 5/31505 (2013.01) [A61M 5/31511 (2013.01); A61M 5/31528 (2013.01); A61M 5/31581 (2013.01); A61M 5/31586 (2013.01); A61M 5/31591 (2013.01); F16H 25/2056 (2013.01); A61M 2005/3152 (2013.01); A61M 2005/31508 (2013.01); A61M 2005/31518 (2013.01); A61M 2005/31598 (2013.01)] 17 Claims
OG exemplary drawing
 
1. A injection assembly comprising:
a housing;
a barrel positioned in the housing, the barrel including a proximal end, a distal end, an axis extending between the proximal and distal ends, and a chamber for storing medicine;
an elongate anti-rotation shaft rotationally fixed to the housing, the shaft having a non circular cross section;
an inner screw having an inner screw opening configured to complementarily receive the anti-rotation shaft to prevent rotation of the inner screw with respect to the anti-rotation shaft but allow respective linear translation along the axis;
a outer screw rotatable with respect to the housing and having an outer screw opening to threadably receive the inner screw, wherein rotation of the outer screw translates the inner screw along the axis and along the anti-rotation shaft; and
a plunger coupled to a distal end of the inner screw and moveable with respect to the chamber to push the medicine out of the chamber when the outer screw is rotated.