Patent ID: 9119920
Filing Date: 2015-09-01
Classification: A61M

Abstract:
1. An injection device for use with a syringe that has a syringe body provided with radially extending wings at a distal end thereof, a needle coupled to a proximal end of the syringe body, and a plunger movable through the syringe body to eject medication from the syringe through the needle, the injection device comprising: a housing defining an inner space sufficient for holding the syringe and facilitating movement of the syringe from a first position in which the needle is contained fully within the housing and a second position in which the needle projects from the housing; a support tube ( a coil spring ( a drive member located within said inner space so that in use the drive member can engage the plunger of the syringe within the housing; a force applicator located within said inner space for providing a force to the drive member which in turn acts on the plunger so as to move the syringe from said first position to said second position and thereafter to move the plunger through the syringe body; a trigger mechanism for retaining the force applicator and the drive member in a cocked configuration and, upon activation of said trigger mechanism, for releasing the force applicator and the drive member; and a pneumatic damper for damping kinetic energy imparted by the drive member to the syringe plunger during all or a part of the movement of the syringe from said first position to said second position, said pneumatic damper comprising a piston having a piston head in engagement with said drive member and a cylinder within which the piston is mounted, said piston and cylinder defining a chamber and one of the piston and cylinder defining a passage for delimiting a first fluid flow path into and out of said chamber, the piston and cylinder being further configured such that movement of the piston outwardly with respect to the cylinder beyond a point defined by said second position creates a second fluid flow path into said chamber, which at least reduces damping of the drive member, during ejection of medication from the syringe through the needle.