Medication injector apparatus with drive assembly that facilitates reset

Abstract

A medication injector apparatus such as an injection pen. The injection pen includes a resettable, cartridge plunger drive assembly including an axially floating nut, a cartridge plunger engaging screw, and a drive clutch movable with the nut and which when rotated causes the screw to screw through the nut. When a cartridge assembly is mounted to the pen base, the floating nut and drive clutch are shifted proximally such that the drive clutch is in torque transmitting engagement with a rotatable drive member of the pen, such that rotation of that drive member results in drive screw advancement through the nut in the distal direction. When the cartridge assembly is not mounted to the pen base, the floating nut and drive clutch are biased distally to disengage the drive clutch from torque transmitting engagement with the rotatable drive member and to thereby allow the drive screw to be reset proximally through the nut to a position more retracted within the pen base. The injection pen also may include an injection clicker assembly having a collar arranged coaxially on a drive sleeve and which oscillates axially on the drive sleeve that rotates during medication dispensing to provide an audible clicking sound that indicates injecting use of the pen. The injection pen also may include a doseable quantity identifier that uses a rotational matrix and a sensor for electrically sensing the arrangement of the dose setting mechanism of the pen, which identifier may be part of a therapeutic dose indicating system that utilizes a cartridge recognizer to recognize a concentration of medication so as to allow an automatic determination of a therapeutic dose. The injection pen further may include an assembly for selectively rotating a drive sleeve of the pen, which assembly has a dial that rotates out during dose setting and which translates in without rotation during dose injecting.

1 - 61 . (canceled) 
     
     
         62 . A medication injector apparatus comprising:
 a housing;   a fluid container mounted to said housing, said fluid container defining a medicine-filled reservoir and including a movable piston at a proximal end of said reservoir, a distal end of said fluid container configured to receive a needle assembly having an injection needle in flow communication with said reservoir when the needle assembly is attached to said distal end;   a drive member disposed within said housing and configured to move said piston toward said distal end to force medicine from said fluid container, the drive member including a drive sleeve rotatable during dose injection;   a dose element disposed within said housing and rotatable during dose setting; and   an electronics assembly configured to sense a relative rotational position of said drive sleeve, said dose element, or both, the electronics assembly including a sensing matrix disposed along at least one of said drive sleeve and said dose element, a sensor arranged relative to the sensing matrix within said housing, and together with the sensing matrix, configured to generate data indicative of said rotational position, and a controller in communication with at least one of the sensing matrix and the sensor and configured to receive said generated data and to determine a total amount of rotational movement of said drive sleeve, said dose element, or both.   
     
     
         63 . The apparatus of  claim 62 , wherein said sensing matrix includes a plurality of rows extending circumferentially. 
     
     
         64 . The apparatus of  claim 63 , wherein said sensor includes a plurality of contacting arms, each of said contacting arms aligned with a different row of said sensing matrix. 
     
     
         65 . The apparatus of  claim 63 , wherein said sensing matrix includes a plurality of columns extending axially. 
     
     
         66 . The apparatus of  claim 65 , wherein said generated data is in the form of the presence or absence of an electrically conductive material at intersections of said rows and columns of said sensing matrix. 
     
     
         67 . The apparatus of  claim 62 , wherein said generated data of said sensing matrix is unique for each rotational arrangement of said drive sleeve or said dose element relative to the housing. 
     
     
         68 . The apparatus of  claim 62 , wherein said dose element and said drive sleeve translate distally without rotation within said housing from a first axial position to a second axial position when said dose setting element translates without rotation during a segment of its travel from a plungeable position to a plunged position. 
     
     
         69 . The apparatus of  claim 68 , wherein said electronics assembly includes a switch that is activated when said dose element and said drive sleeve travel from said first axial position to said second axial position to signal a transition of the apparatus from a dose setting mode to a dose injection mode, wherein said travel segment of said dose setting element starts at said plungeable position. 
     
     
         70 . The apparatus of  claim 68 , wherein said drive sleeve is moved from said first axial position toward said second axial position by direct engagement with said dose element. 
     
     
         71 . The apparatus of  claim 68 , wherein said dose element is configured to reset for a subsequent dosing when said dose element translates without rotation from said plungeable position to said plunged position. 
     
     
         72 . The apparatus of  claim 68 , further comprising means for preventing rotation of said dose element relative to said housing and halting further distal axial motion of said drive sleeve when said dose element and said drive sleeve are disposed in said second axial position, whereby axial travel of said dose setting element after said travel segment and toward said plunged position rotates said drive sleeve. 
     
     
         73 . The apparatus of  claim 62 , wherein said fluid container contains at least one of insulin and human growth hormone.