Multiple use disposable injection pen

Abstract

A medication injection method where a dose set knob of a medication injection pen is rotated with respect to the housing of the medication injection pen during dose setting and dose correcting, a driver is selectively engages with the dose set knob, the driver being rotatably fixed with respect to the housing during dose setting and dose correcting, the driver is moved axially with the dose set knob during the dose setting and the dose correcting, and the driver is rotated with the dose set knob during an injection.

What is claimed is: 
     
         1 . A medication injection pen, comprising:
 a housing;   a dose set knob that rotates with respect to the housing during dose setting and dose correcting;   a driver selectively engaged with the dose set knob, the driver rotatably fixed with respect to the housing during dose setting and dose correcting; and   a clicker operatively engaged between said dose set knob and said driver;   wherein the driver moves axially with the dose set knob during dose setting, dose correcting, and dose injecting,   the dose set knob rotating with respect to the clicker during the dose setting generates a first audible indicia, and   the clicker rotating with respect to the driver during the dose correcting generates a second audible indicia.   
     
     
         2 . The medication injection pen according to  claim 1 , wherein during the dose injecting the driver rotates with the dose set knob and the clicker is rotationally fixed with respect to the driver and the dose set knob. 
     
     
         3 . The medication injection pen according to  claim 1 , further comprising
 a piston rod rotatably fixed with respect to the housing during the dose setting, the dose correcting and the dose injecting.   
     
     
         4 . The medication injection pen according to  claim 3 , wherein the dose set knob rotates to cause the piston rod to axially move with respect to the housing during the dose injecting. 
     
     
         5 . The medication injection pen according to  claim 1 , further comprising a brake tower rotatably and axially fixed to the housing. 
     
     
         6 . The medication injection pen according to  claim 5 , wherein the brake tower engages the driver to prevent the driver from rotating during the dose correcting. 
     
     
         7 . The medication injection pen according to  claim 6 , wherein the engaging between the brake tower and the driver is overcome to allow the driver to rotate during the dose injecting. 
     
     
         8 . The medication injection pen according to  claim 1 , further comprising
 a push button depressible to initiate the dose injecting and to engage the dose set knob with the driver.   
     
     
         9 . The medication injection pen according to  claim 1 , further comprising 
 a leadscrew rotatably fixed to the driver,   wherein the driver moves axially with respect to the leadscrew during the dose setting and the dose correcting.   
     
     
         10 . The medication injection pen according to  claim 9 , further comprising 
 a piston rod rotatably fixed with respect to the housing during the dose injecting,   wherein the leadscrew is threadably engaged to the piston rod such that rotation of the leadscrew during the dose injecting causes the piston rod to move axially.   
     
     
         11 . The medication injection pen according to  claim 10 ,
 wherein the piston rod is essentially a hollow cylinder, and   a brake core member disposed within the piston rod substantially prevents the rotation of the piston rod during the dose injecting.   
     
     
         12 . The medication injection pen according to  claim 11 , wherein the brake core member comprises an open portion to receive the lead screw. 
     
     
         13 . The medication injection pen according to  claim 12 , wherein 
 the piston rod comprises a protrusion on an inner surface thereof; and   the open portion of the brake core member engages the protrusion to prevent rotation of the piston rod.   
     
     
         14 . The medication injection pen according to  claim 10 , wherein 
 the piston rod comprises a groove in an inner surface thereof,   the leadscrew comprises a thread on an outer surface thereof, and   the thread of the lead screw engages the groove of the piston rod such that the rotation of the leadscrew during the injecting causes the piston rod to move axially.   
     
     
         15 . The medication injection pen according to  claim 1 , wherein the clicker is rotationally fixed with respect to the driver during the dose setting . 
     
     
         16 . The medication injection pen according to  claim 1 , wherein the clicker is rotationally fixed with respect to the dose set knob during the dose correcting. 
     
     
         17 . The medication injection pen according to  claim 5 , further comprising 
 a wave clip,   wherein a distal end of the break tower is disposed toward a distal end of the housing, and the wave clip is provided at the distal end of the break tower to bias a cartridge configured with respect to the distal end of the housing to prevent movement of the cartridge with respect to the housing during the dose injecting.