Pen needle magazine

Abstract

An attachable needle assembly (102) for use on a medication delivery pen (104), the needle assembly (102) comprising a housing (110) enclosing a hub (106) having a communication needle (108) configured to engage the medication delivery pen (104) and pierce a reservoir septum of the medication delivery pen (104), a communication septum (172, 176) of the needle assembly (102) defining a septum chamber (180, 182) that is in fluid communication with the communication needle (108), a plurality of needles (118) disposed in the communication septum (172, 176), a follower ring (130) that determines which needle (124) of the plurality of needles (118) is to be selected, and a snap ring (136) that exposes the selected needle (124) and moves the selected needle (124) in fluid communication with the septum chamber (180, 182), wherein when the housing (110) is in a first position, the plurality of needles (118) is not exposed, and when the housing (110) is in a second position, the selected needle (124) is in fluid communication with the septum chamber (180, 182) and exposed for medicament delivery.

1 . An attachable needle assembly for use on a medication delivery pen, the needle assembly comprising:
 a plurality of needles disposed in a guiding post, the guiding post is fixed to a bottom guide having a plurality of external fins;   a communication septum is disposed in a septum housing having a plurality of external ridges;   a follower ring includes two tooth shaped followers, the follower ring rotates and identifies which needle of the plurality of needles is to be selected; and   a snap ring that exposes the selected needle and move the selected needle to be in fluid communication with the communication septum, wherein   the two tooth shaped followers of the follower ring contact the plurality of external fins of the bottom guide and the plurality of external ridges of the septum housing to rotate the follower ring.   
     
     
         2 . The attachable needle assembly of  claim 1 , further comprising a housing enclosing the plurality of needles, the communication septum, the follower ring and the snap ring. 
     
     
         3 . The attachable needle assembly of  claim 1 , wherein the tooth shaped followers alternate contact with the plurality of external fins of the bottom guide and the plurality of external ridges of the septum housing to rotate the follower ring and select each needle consecutively from a first needle to a last needle of the plurality of needles. 
     
     
         4 . The attachable needle assembly of  claim 2 , wherein when the housing is moving from the first position to the second position, one of the two shaped followers contacts one of the plurality of external fins of the bottom guide and causes the follower ring to rotate. 
     
     
         5 . The attachable needle assembly of  claim 2 , wherein when the housing is moving from the second position to the first position, one of the two shaped followers contacts one of the plurality of external ridges of the septum housing and causes the follower ring to rotate. 
     
     
         6 . The attachable needle assembly of  claim 2 , wherein the housing is configured to move from the first position to the second position for each of the plurality of needles. 
     
     
         7 . The attachable needle assembly of  claim 1 , wherein the two tooth shaped followers are circumferentially offset from each other on an internal surface of the follower ring. 
     
     
         8 . The attachable needle assembly of  claim 1 , wherein the two tooth shaped followers do not simultaneously contact the plurality of external ridges of the septum housing and the plurality of external fins of the bottom guide. 
     
     
         9 . The attachable needle assembly of  claim 1 , wherein
 one of the two tooth shaped followers is disposed at a top portion of the follower ring; and   an other of the two tooth shaped follower is disposed at a bottom portion of the follower ring.   
     
     
         10 . The attachable needle assembly of  claim 1 , wherein a tooth of one of the two tooth shaped followers and a tooth of an other of the two tooth shaped followers are oriented in opposing directions. 
     
     
         11 . The attachable needle assembly of  claim 1 , wherein
 one of the two tooth shaped followers contacts the plurality of external fins of the bottom guide; and   an other of the two tooth shaped followers contacts the plurality of external ridges of the septum housing.   
     
     
         12 . A method of operating an attachable needle assembly on a medication delivery pen, the method comprising:
 establishing fluid communication between the medication delivery pen and a communication septum of the needle assembly;   disposing a plurality of needles in the communication septum of the needle assembly;   moving a portion of the needle assembly upward or downward to cause rotation of a follower ring and identify which needle of the plurality of needles is to be selected;   exposing the selected needle upon downward movement of the portion of the needle assembly; and   moving the selected needle to be in fluid communication with the communication septum of the needle assembly, wherein   the portion of the needle assembly alternately moves upward and downward to rotate the follower ring and select each needle consecutively from a first needle to a last needle of the plurality of needles.   
     
     
         13 . The method of  claim 12 , further comprising rotating the follower ring during the downward movement and during the upward movement. 
     
     
         14 . The method of  claim 12 , wherein the portion of the needle assembly alternately moves upward and downward to automatically rotate the follower ring and select each needle consecutively.