Patent ID: 7927303

Claim:
A medicine injection device system, comprising: a tube having a muzzle end; a syringe subassembly cavity within the tube; a syringe subassembly within the tube and sized to slide within the cavity, the syringe subassembly having a reservoir containing fluid medication, a needle, and a plunger for forcing the fluid medication from the reservoir through the needle; a driver for forcing the syringe subassembly to penetrate flesh and displace fluid medication through the needle, the driver being movable between a cocked position and extended positions; a penetration control element which controls penetration of the needle to a depth stop position to provide a desired final penetration depth; the penetration control element being configured to be entirely contained in the tube and to encircle the needle; the penetration control element comprising a coil spring selected from a series of coil springs of different winding configurations with different compressed axial lengths, at least some of the coil springs of said series having three or more complete dead windings; the selected coil spring being positioned in the cavity to be engaged and compressed by the syringe subassembly to its contracted axial length in response to movement of the syringe subassembly, to thereby stop movement of the syringe subassembly at a selected stop position with the needle at a selected needle penetration depth; the selected coil spring having at least three complete dead windings.