Patent ID: 9234729
Filing Date: 2016-01-12
CPC Classification: A61M,F42B

Claim Text:
1. An improved injection dart of the type having a dart body, a ferrule at a forward end of said body to which a cannula is attached, a drug containment chamber located in said dart body, a plunger initially positioned at a rear end of said drug containment chamber, mechanical or chemical means to provide pressure to and exert force on a rear end of said plunger causing the plunger to move forwardly toward said cannula whereby a drug fluid within the drug containment chamber is discharged through an open end of said cannula at a variable flow rate, the improvement comprising: a flow restrictor formed of a deformable material positioned at a forward end of said dart body immediately juxtaposed against a rear end surface of said cannula, said flow restrictor utilized to alter said variable flow rate only during times when said drug fluid within the drug containment chamber is being discharged through said cannula, said flow restrictor having a generally cylindrical restrictor body, said flow restrictor having a radially outwardly extending flange at a forward end thereof, said flange securely held in position between a forward end of said dart body and said ferrule, said flow restrictor having a flow channel bore extending through a centerline of said cylindrical restrictor body from a forward end of said restrictor body to a rearward end thereof, said restrictor body also having a recess in a rearward end thereof, said recess being symmetrically aligned along said centerline, whereby said flange holds said restrictor in a position where an inner bore of said cannula is precisely aligned with said restrictor bore and whereby said variable flow rate is altered by a radially inward deformation of the restrictor reducing a cross-sectional area of said flow channel bore thereby reducing said variable rate of flow which passes into the open end of the cannula such that all flow rates above a maximum flow rate are restricted to be less than said maximum flow rate.