Patent ID: 8915881
Filing Date: 2014-12-23
Classification: A61M

Abstract:
1. Injection device, comprising a housing being adapted to receive in its proximal housing portion a container with an injection fluid and to receive in its distal housing portion a dose setting and injection mechanism, wherein the mechanism includes a piston rod being axially displaceable with respect to the housing for dispensing injection fluid from the container, wherein the piston rod has an outer thread and is arranged torque proof with respect to the housing, a dose setting means comprising a threaded element, which threaded element has an inner thread being in engagement with the outer thread of the piston rod, is designed so that its axial position relative to the housing is changeable, and is rotatable relative to the piston rod and relative to the housing during setting of an injection dose, wherein the threaded element is held in torque proof manner relative to the piston rod and to the housing during the injection of the beforehand set injection dose, wherein the threaded element and the piston rod are axially displaceable together with respect to the housing, wherein the mechanism further comprises a holding clamp being in contact with the piston rod to immobilize the axial displacement of the piston rod during use of the device except for the dispensing of the injection dose, wherein the holding clamp is axially fixed with respect to the housing and wherein the piston rod has two longitudinal planar outer surfaces cut in the outer thread and being arranged in parallel to each other on opposing sides of the piston rod, characterized in that the holding clamp is in contact with both parallel outer planar surfaces of the piston rod and exerts a compressive force on the piston rod wherein the holding clamp has two clamping portions each of which being in contact with a respective planar outer surface of the piston rod to frictionally engage with the piston rod and wherein the holding clamp is made from a bent metal wire and the clamping portions have a curvature being convex in direction to the piston rod and wherein the clamping portions of the holding clamp protrude with their respective convex wire portions in an opening of a guiding element in which the piston rod is axially guided and is held in torque proof manner due to an engagement of the outer planar surfaces of the piston rod with corresponding planar surfaces of the opening of the guiding element.