Reusable medication delivery pen
AssigneeBecton, Dickinson and Company
InventorDavid Balkwill
Life of this patent
Estimating the term…
Abstract
An injection device medication delivery pen is provided for injecting fluids such as insulin within body tissue. The device includes a housing, a piston rod movably mounted within the housing, and a dose setting mechanism for controlling the movement of the piston rod with respect to a fluid containing cartridge removably positioned within the housing. The piston rod includes a plunger and a lead screw slidably positioned within the plunger. The plunger and lead screw are coupled by a pair of half nuts. The half nuts may be uncoupled from the lead screw in order to allow it to slide freely with respect to the plunger. A new cartridge may accordingly be installed quickly and easily as the lead screw is easily displaced by a new cartridge.
Claims10
An injection device for injecting selected dosages of fluid, comprising:
- an elongate housing;
- a manually operable plunger positioned at least partially within said housing and axially movable within said housing;
- a lead screw having external threads positioned at least partially within said plunger and axially slidable therein;
- means for threadably engaging said lead screw;
- means for selectively moving said means for threadably engaging said lead screw into and out of engagement with said lead screw, whereby said lead screw is freely slidable with respect to said plunger when said means for threadably engaging said lead screw is disengaged from said lead screw, said lead screw and plunger being slidable as a unit with respect to said housing when said means for threadably engaging said lead screw is engaged with said lead screw;
- means for securing a fluid containing cartridge having an internal piston to said housing so that said lead screw can move said piston, said means for securing a cartridge being engageable with said means for selectively moving such that said lead screw is disengaged from said means for threadably engaging said lead screw when said means for securing is disengaged from said housing;
- and
- wherein manual force applied to said plunger, when said means for threadably engaging said lead screw is engaged with said lead screw, is transferred to said lead screw for moving said piston to expel fluid from said cartridge.
Dependencies are inferred from the claim text.