A needle-free injection device suitable for delivering a therapeutic substance into the intradermal space of a patient. The needle-free injection device includes an injector body defining a syringe end. The device also includes a first handle attached with a hinge to the injector body such that the first handle pivots between an open and a closed position and remains attached to the injector body during an injection, a main spring positioned within the injector body, a return sleeve engaged with the main spring, and a first linkage between the first handle and the return sleeve. The first linkage causes the return sleeve to move away from the syringe end of the injector body when the first handle is moved from the open position to the closed position, thereby compressing the main spring. Needle-free injection systems and methods of operating a needle-free injection device are also disclosed.
