Disposable injection device with locking structure to prevent reuse

A disposable injection device, comprising:

• an outer housing comprising:
• a housing body having a hollow shape with an open upper portion;
• a pair of separation guide portions constituting the open upper portion of the housing body, the pair of separation guide portions comprising a separation guide plate extending outward from an upper end of the housing body, a separation guide protrusion extending upward from a top surface of the separation guide plate;
• and
• a reuse preventing portion formed on a side surface of the housing body;
• a locking module configured to be position-changeably coupled in the outer housing, the locking module comprising:
• a first locking body position-changeably located in the housing body;
• a cartridge coupling portion constituting an upper portion of the first locking body;
• a locking portion protruding from an outer surface of the first locking body;
• and
• unlocking protrusions formed on both sides of the first locking body and spaced apart from the first locking body and located in a higher position in the first locking body than the locking portion;
• an elastic spring located in a compressed state at a lower end of the locking module in the outer housing;
• a liquid cartridge coupled to the locking module and configured for containing an injection solution therein;
• and
• a pressurizing piston unit configured to pressurize the inside of the liquid cartridge and discharge the injection solution, the pressurizing piston unit comprising:
• a pressure head;
• a separation plate located in a plate shape under the pressure head and configured to allow the pair of separation guide portions to be opened outward;
• and
• a plunger longitudinally formed from a lower portion of the pressure head and slidably coupled into the cartridge body,
• wherein the reuse preventing portion includes:
• a slide groove longitudinally formed in a vertical direction in the housing body to guide a movement when the locking module accommodated in the outer housing is temporarily released and raised;
• protrusion grooves formed on both sides of an upper portion of the slide groove to be spaced apart from each other;
• a lowering preventing protrusion configured to connect an upper end of the slide groove to an upper end of the protrusion groove, the lowering preventing protrusion configured to be bent inward and having a stepped shape with an inclined lower end, wherein the protrusion grooves are configured to secure a space for flexible movement of the lowering preventing protrusion;
• and
• protrusion mount grooves formed over the lowering preventing protrusion and passing through the housing body, the protrusion mount grooves configured to prevent a raised locking module from being lowered again,
• wherein the protrusion mount grooves are configured to be coupled to the unlocking protrusions to fix a position of the first locking body in the outer housing before the pressuring piston unit is lowered,
• wherein, when the pressurizing piston unit is lowered, a separation distance between the pair of separation guide portions is gradually increased through a process in which the separation plate moves along an inner surface of the pair of separation guide protrusion so that the unlocking protrusions are separated from the protrusion mount grooves to temporarily release a fixing between the locking module and the outer housing.