Patent ID: 7749192

Claim:
In combination with a disposable injector with a housing ( 10 ) that contains at least one mechanical spring energy reservoir ( 50 ), at least one cylinder/piston unit ( 100 ) for filling at least temporarily with active substance, at least one piston-actuating rod ( 71 ) and, at least one trigger unit ( 80 ), the improvement which comprises: the at least one spring energy reservoir ( 50 ) comprising a pretensioned helical spring element ( 77 ) in mechanical communication with the at least one piston actuating rod ( 71 ), the at least one piston actuating rod ( 71 ) including a piston slide ( 76 ) proximate the lower area of the actuating rod ( 71 ) adapted to engage a piston ( 111 ) of the cylinder/piston unit ( 100 ), the piston ( 111 ) adapted to engage a cylinder ( 101 ) of cylinder/piston unit ( 100 ) upon actuation of the injector, a flat rod plate ( 73 ) proximate the central area of the actuating rod ( 71 ) adapted to support the helical spring ( 77 ), and a cylindrical spring-guiding bar ( 72 ) proximate the upper area of the actuating rod ( 71 ) adjoining the flat rod plate ( 73 ), the cylindrical spring-guiding bar ( 72 ) passing through the interior of the helical spring element ( 77 ), and a U-shaped tensioning band ( 78 ) adapted to surround the outer periphery of the spring element ( 77 ) in at least some areas on opposite sides thereof, an anvil ( 51 ) having a lower end face ( 66 ) and an upper end face ( 53 ), the lower end face ( 66 ) of the anvil ( 51 ) abutting the spring element ( 77 ), the anvil ( 51 ) disposed in operative position proximate the closed end of the U-shaped tensioning band ( 78 ), the anvil ( 51 ) having a pair of oppositely disposed band-guiding grooves ( 63 ) of predetermined depth therein extending between the lower end face ( 66 ) and the upper end face ( 53 ) of the anvil ( 51 ), the spring element ( 77 ) is held in a pretensioned position by the tensioning band ( 78 ); the trigger unit ( 80 ) comprising a manually actuated cutting tool ( 90 ), the cutting tool ( 90 ) in operative position proximate the closed end of U-shaped tensioning band ( 78 ) and adapted to cut the tensioning band ( 78 ) upon manual actuation thereof, the anvil ( 51 ) for providing a bearing for the tensioning band ( 78 ) to be severed by the cutting tool ( 90 ), the cutting tool ( 90 ) for triggering the release of energy of the helical spring element ( 77 ) by severing the tensioning band ( 78 ) at least in one location, or weakening it, the weakening causing an immediate tearing of the tensioning band ( 78 ) causing piston slide ( 76 ) to operatively engage piston ( 111 ) and piston ( 111 ) to operatively engage cylinder ( 101 ) to eject the active substance from cylinder ( 101 ).