Injection Device

Abstract

An injection device ( 1 ) with a travelling clutch which can be shifted between two different positions by the activation of an injection button. In the first position, the injection button and the driver ( 70 ) is allowed to rotate relatively to the piston rod ( 60 ), which is blocked from rotation by the clicker element ( 80 ). In the second position, the drive sleeve ( 70 ) and the injection button is axially movable while the piston rod ( 60 ) is allowed to rotate.

1 . A drug delivery device ( 1 ) comprising:
 A housing ( 10 ),   A piston rod ( 60 ) having a proximal thread ( 61 ) and a distal thread ( 62 ),   A nut member ( 15 ) which is not axially displaceable in the housing ( 10 ) and which has an inner thread ( 16 ) mating the distal thread ( 62 ) of the piston rod ( 60 ) such that the piston rod ( 60 ) is screwed in a distal direction when rotated relatively to the nut member ( 15 ),   A drive sleeve ( 70 ) which has an inner thread ( 71 ) mating the proximal thread ( 61 ) of the piston rod ( 60 ) such that the piston rod ( 60 ) is rotated when the driver sleeve ( 70 ) is axially moved relatively to the piston rod ( 60 )   Wherein a releasable coupling ( 90 ,  80 ,  30 ) operational between a first position and a second position is provided between the piston rod ( 60 ) and the drive sleeve ( 70 ) which coupling ( 90 ,  80 ,  30 ) in the first position prevents rotation of the piston rod ( 60 ) while allowing rotation of the drive sleeve ( 70 ) and in the second position prevents rotation of the drive sleeve ( 70 ) whilst allowing rotation of the piston rod ( 60 ).   
   
   
       2 . A drug delivery device ( 1 ) according to  claim 1  wherein the coupling ( 90 ,  80 ,  30 ) comprises a slider ( 90 ) slidable connected to the housing ( 10 ). 
   
   
       3 . A drug delivery device ( 1 ) according to  claim 2  wherein the coupling ( 90 ,  80 ,  30 ) comprises a clicker element ( 80 ) coupled to the slider ( 90 ). 
   
   
       4 . A drug delivery device ( 1 ) according to  claim 3  wherein the clicker element ( 80 ) is both axially and rotational locked to the slider ( 90 ) in the first position. 
   
   
       5 . A drug delivery device ( 1 ) according to  claim 3  wherein the clicker element ( 80 ) is rotational released from the slider ( 90 ) in the second position. 
   
   
       6 . A drug delivery device ( 1 ) according to  claim 5  wherein the clicker element ( 90 ) is shifted between its locked and its released position by axial movement of an injection button ( 30 ). 
   
   
       7 . A drug delivery device ( 1 ) according to  claim 6  wherein the injection button ( 30 ) is connected to the drive sleeve ( 70 ) in a way making the injection button ( 30 ) axially displaceable relatively to the drive sleeve ( 70 ).