Injection device with a spring for a needle protecting sleeve

Abstract

An injection device including a housing, a needle guard sleeve displaceable relative to the housing, and a spring coupled to the guard sleeve such that the guard sleeve can be moved by the spring distally from a proximal position to an end position, the spring also being coupled to a forward drive element displaceable relative to the housing in a drive direction wherein the spring is tensioned upon a movement of the forward drive element in the forward drive direction.

What is claimed is: 
     
         1 . An injection device comprising:
 a housing configured to enclose a product container connected to an injection needle and having a longitudinal axis;   a piston rod configured to act on a piston in a delivery direction for product delivery;   a delivery spring biasing the piston rod;   a needle protecting sleeve comprising an activating element, the needle protecting sleeve shiftable along the longitudinal axis relative to the housing from an initial position in which the needle protecting sleeve protrudes beyond a distal end of the housing to a proximal position during manual insertion of the injection needle;   a restoring spring for shifting the activating element distally from the proximal position to an end position;   a triggering element configured to release a blocking connection of the piston rod in which the piston rod is prevented from moving in the delivery direction by the biased delivery spring; and   a releasing member comprising a protrusion directed radially inward and configured to engage with an outer surface of the piston rod in an engagement to prevent the piston rod from moving in a distal direction relative to the product container, wherein the releasing member is prevented from disengaging from the engagement by a surface of a supporting element directed radially inward and preventing the releasing member from moving radially outward transverse to the longitudinal axis, and wherein by shifting the supporting element along the longitudinal axis, the releasing member is permitted to disengage from the engagement to thereby release the piston rod for distal movement relative to the product container in the product delivery direction by the biased delivery spring.   
     
     
         2 . The device of  claim 1 , wherein the triggering element causes the releasing member to shift. 
     
     
         3 . The device of  claim 2 , wherein in the initial position, the triggering element is prevented from undergoing a triggering movement. 
     
     
         4 . The device of  claim 3 , wherein in the proximal position, the triggering element is permitted to undergo the triggering movement. 
     
     
         5 . The device of  claim 2 , wherein the triggering element is arranged at a proximal end of the device and configured to be moved in a distal direction during a triggering movement. 
     
     
         6 . The device of  claim 1 , wherein the triggering element is arranged at a proximal end of the device and configured to be moved in a distal direction during a triggering movement. 
     
     
         7 . The device of  claim 1 , wherein in the end position, the needle protecting sleeve covers a distal end of the injection needle. 
     
     
         8 . The device of  claim 1 , wherein in the initial position, the needle protecting sleeve covers a distal end of the injection needle. 
     
     
         9 . The device of  claim 1 , wherein in the initial position, the triggering element is prevented from undergoing a triggering movement, and in the proximal position, the triggering element is permitted to undergo the triggering movement. 
     
     
         10 . The device of  claim 1 , wherein in the end position, the needle protecting sleeve is blocked from shifting axially in a proximal direction relative to the housing. 
     
     
         11 . An injection device comprising:
 a housing configured to enclose a product container connected to an injection needle and having a longitudinal axis;   a piston rod configured to act on a piston in a delivery direction for product delivery;   a delivery spring biasing the piston rod;   a needle protecting sleeve comprising an activating element, the needle protecting sleeve shiftable along the longitudinal axis relative to the housing from an initial position in which the needle protecting sleeve protrudes beyond a distal end of the housing to a proximal position in which the needle protecting sleeve is shifted into the housing;   a restoring spring for shifting the activating element distally from the proximal position to an end position in which the needle protecting sleeve protrudes beyond a distal end of the injection needle;   a triggering element configured to release a blocking connection of the piston rod in which the piston rod is prevented from moving in the delivery direction by the biased delivery spring; and   a releasing member configured to form an engagement with an outer surface of the piston rod to prevent the piston rod from moving in a distal direction relative to the product container,   wherein the releasing member and the piston rod are held in the engagement by a supporting element, the supporting element blocking the releasing member from disengaging from the engagement with the piston rod,   wherein the supporting element is shiftable relative to the releasing member, and after shifting, the supporting element no longer blocks the releasing member from disengaging from the engagement,   wherein in the initial position, the triggering element is prevented from releasing the blocking connection, and in the proximal position, the triggering element is permitted to release the blocking connection.   
     
     
         12 . The injection device of  claim 11 , wherein the triggering element causes the releasing member to shift. 
     
     
         13 . The injection device of  claim 11 , wherein movement of the needle protecting sleeve from the initial position to the proximal position permits the injection needle to be manually inserted. 
     
     
         14 . The injection device of  claim 11 , wherein in the end position, the needle protecting sleeve is blocked from shifting proximally relative to the housing. 
     
     
         15 . The injection device of  claim 11 , wherein the releasing member comprises a protrusion directed radially inward and engages with an outer surface of the piston rod in the engagement, and wherein the releasing member is held in the engagement by a surface of the supporting element directed radially inward. 
     
     
         16 . The injection device of  claim 15 , wherein upon releasing the engagement, the releasing member moves radially outward transverse to the longitudinal axis.