One-way injector with continuosly charged spring energy store

The disclosure relates to a one-way injector having a housing in which at least one mechanical spring energy store, at least one piston/cylinder unit, which can be at least temporarily filled with an active substance, at least one piston-actuating plunger and at least one tripping unit are arranged. To this end, the spring energy store comprises a preloaded spring element. The spring element is held in the preloaded position by a tension means surrounding at least a region of the spring. The tripping unit comprises a cutting tool which, in order to release the energy of the spring energy store, severs or weakens the tension means at at least one point, the weakening immediately tearing the tension means. With the present disclosure, a one-way injector is developed which, with a small overall size, has only a few components and ensures reliable mounting and functioning with simple manipulation.