Patent ID: 7749187

Claim:
A needleless injection device including a lower part receiving an agent cartridge and an upper part providing the energy needed for the injection, the upper part containing energy store units, including at least one start unit and at least one supplementary unit, capable of elastic form-change, the device further comprising: a lock mechanism maintaining tension of the energy store units and a release mechanism for releasing the lock mechanism; a tubular section of the lower part, provided with an external thread, extending into the upper part, the external thread coupling with an internal thread provided in the upper part, wherein the lower part is attached to the upper part in a revolving manner, and is movable telescopically within the upper part for producing a tension state of the energy store units; and a spacer moveable independently of the at least on supplementary unit within the upper part, the spacer maintaining a uniform longitudinal space between the at least one start unit and the lock mechanism from the time the tension state of the energy store units is produced until the lock mechanism is released, wherein: the at least one start unit is capable of storing 60-90% of the energy needed for total discharge when incurring a reversible elastic distortion of no more than 25% of an internal length of the agent cartridge; and wherein the at least one start unit includes a bundle of polyurethane springs fitted inside the device in a separate case; and upon release of the lock mechanism, the spacer transfers without impact the stored energy from the springs of the at least one start unit via the lock mechanism through a piston to contents of the agent cartridge, the stored energy being transferred without striking another body against the piston and with the cartridge and piston rod being in continuous contact during firing of the injection.