Medical injector with slidable sleeve activation

A medical injector comprising:

• a body;
• a displaceable plunger disposed in said body, said plunger having at least one thread formed thereon;
• a stem disposed in said body, said stem having at least one thread formed thereon;
• a button fixed to said stem;
• a spring disposed to advance said button away from said body;
• and,
• a releasable retainer for releasably retaining said button against force of said spring,
• wherein, upon a predetermined extent of relative movement between said plunger and said stem, said thread of said plunger threadably engages said thread of said stem such that said stem rotates, rotation of said stem causing said releasable retainer to release said button thereby allowing said spring to advance said button.

A medical injector comprising:

• a body;
• a displaceable plunger disposed in said body, said plunger having at least one thread formed thereon;
• a spring disposed to advance said plunger;
• a stem disposed in said body, said stem having at least one thread formed thereon;
• a button fixed to said stem;
• a secondary spring disposed to advance said button away from said body;
• a first releasable retainer for retaining said plunger in a first state against force of said spring;
• a sleeve disposed on said body, said sleeve being slidable relative to said body;
• and,
• a second releasable retainer for releasably retaining said button against force of said secondary spring,
• wherein sliding movement of said sleeve over a predetermined extent relative to said body results in said first releasable retainer releasing said plunger thereby allowing said spring to advance said plunger, and,
• wherein, upon a predetermined extent of relative movement between said plunger and said stem, said thread of said plunger threadably engages said thread of said stem such that said stem rotates, rotation of said stem causing said second releasable retainer to release said button thereby allowing said secondary spring to advance said button.