Injection Device Having Variable Dosing

An injection device for injecting medicament in a patient comprising:

• a housing configured to house a fluid container having a piston and a fluid reservoir having one of a plurality of volumes of medicament, the fluid container including an injection conduit fluidly coupled to the fluid reservoir configured to define a fluid pathway from the fluid reservoir to the patient;
• a ram coupled to the piston and configured to expel the medicament from the fluid reservoir through the injection conduit;
• a spring biasing the ram toward the fluid container in an initial position;
• a nut threadably coupled to the ram, the nut having a plurality of ring shaped grooves or projections;
• a latch fixed relative to the housing and engaging a predetermined one of the plurality of ring shaped grooves or projections to retain the ram in one of a plurality of axial positions against a force of the spring in the initial position, the nut being rotatable relative to the latch in the initial position;
• and
• a dose setting knob rotatably coupled to the housing and rotatably fixed and axially moveable relative to the ram in the initial position.

An injection device for injecting medicament in a patient comprising:

• a housing configured to house a fluid container having a piston and a fluid reservoir having one of a plurality of volumes of medicament, the fluid container including an injection conduit fluidly coupled to the fluid reservoir configured to define a fluid pathway from the fluid reservoir to the patient;
• a ram coupled to the piston and configured to expel the medicament from the fluid reservoir through the injection conduit, the ram having a radially extending wing;
• a latch axially fixed and rotatably moveable relative to the ram, the ram having a plurality of radial features;
• a spring biasing the latch toward the fluid container in an initial position;
• a retainer fixed relative to the housing and engaging a predetermined one of the plurality of radial features to retain the ram in one of a plurality of axial positions against a force of the spring in the initial position;
• a stop having a plurality of axially extending and radially projecting slots each extending a different axial depth, the ram being rotatable to align the wing with one of the plurality of slots in the initial position and the wing configured to engage the one of the plurality of slots in a fired position;
• and
• a dose setting knob rotatably coupled to the housing, the ram being rotatably fixed and axially moveable relative to the dose setting knob.

A method for assembling an injection device comprising:

• inserting a fluid container having a fluid reservoir including one of a plurality of volumes of medicament into a housing, the fluid container including an injection conduit fluidly coupled to the fluid reservoir configured to define a fluid pathway from the fluid reservoir to the patient;
• setting a volume setting mechanism based on a size of the one of the plurality of volumes of medicament;
• coupling the volume setting mechanism to a firing mechanism;
• and
• coupling the firing mechanism to the fluid reservoir, the firing mechanism configured to expel the medicament from the fluid reservoir through the injection conduit, the firing mechanism being coupled to a dose setting mechanism configured to select all or a fraction of the one of the plurality of volumes of medicament that is injected from the injection conduit when the firing mechanism is actuated.

An injection device for injecting medicament in a patient comprising:

• a housing configured to house a fluid reservoir;
• an injection conduit fluidly coupled to the fluid reservoir configured to define a fluid pathway from the fluid reservoir to the patient;
• a firing mechanism coupled to the fluid reservoir and configured to expel the medicament from the fluid reservoir through the injection conduit;
• and
• a safety cap coupled to a distal end of the housing, the safety cap being coupled to the firing mechanism such that decoupling the safety cap from the housing allows the firing mechanism to advance a predetermined distance relative to the fluid reservoir to prime the fluid reservoir.