Medicinal solution administration device

A medicinal solution administration device comprising:

• a casing having a hollow cylindrical shape;
• a syringe comprising a cylinder that is housed in the casing and filled with a medicinal solution, and a puncture needle that communicates with the cylinder and is configured to administer the medicinal solution to a living body;
• a needle cover having a hollow cylindrical shape, wherein the needle cover is disposed inside the casing and covering a distal side of the syringe, and is configured to be displaced in a proximal direction relative to the casing when pressed against a puncture target;
• a cap that is detachably disposed on a distal end of the needle cover and configured to be detached before the puncture target is punctured with the puncture needle;
• and
• a drive unit that is housed on a proximal side of the casing, wherein the drive unit is configured to bias a gasket of the syringe toward a distal end of the casing by a plunger along with movement of the needle cover in the proximal direction, wherein the drive unit comprises:
• a sliding member movable along the axial direction of the casing, and
• an elastic member that biases the sliding member toward the syringe;
• and
• a locking pin comprising a cylindrical pin main structure that blocks the plunger from moving in a distal direction in an initial state and allows the plunger to move in the distal direction along with the movement of the needle cover in the proximal direction;
• wherein:
• the cap comprises a plurality of retaining arms that restrict the movement of the needle cover in the proximal direction relative to the casing when the cap is attached to the casing and allow the movement of the needle cover in the proximal direction when the cap is detached from the casing;
• and
• the medicinal solution administration device further comprises a coupling mechanism that couples a proximal end of the needle cover and the drive unit to each other in an axial direction of the casing, wherein the coupling mechanism comprises:
• a first connection disposed on the sliding member, and
• a second connection disposed on the proximal end of the needle cover and coupled to the first connection, wherein:
• the second connection comprises a projection protruding in a direction perpendicular to the axial direction of the casing, and
• the first connection comprises a flexible arm portion engaged with the projection and elastically deformable by contact with the projection.

A medicinal solution administration device comprising:

• a casing having a hollow cylindrical shape;
• a syringe comprising a cylinder that is housed in the casing and filled with a medicinal solution, and a puncture needle that communicates with the cylinder and is configured to administer the medicinal solution to a living body;
• a needle cover having a hollow cylindrical shape, wherein the needle cover is disposed inside the casing and covering a distal side of the syringe, and is configured to be displaced in a proximal direction relative to the casing when pressed against a puncture target;
• a cap that is detachably disposed on a distal end of the needle cover and configured to be detached before the puncture target is punctured with the puncture needle;
• and
• a drive unit that is housed on a proximal side of the casing, wherein the drive unit is configured to bias a gasket of the syringe toward a distal end of the casing by a plunger along with movement of the needle cover in the proximal direction, wherein the drive unit comprises:
• a sliding member movable along the axial direction of the casing, and
• an elastic member that biases the sliding member toward the syringe;
• and
• a locking pin comprising a cylindrical pin main structure that blocks the plunger from moving in a distal direction in an initial state and allows the plunger to move in the distal direction along with the movement of the needle cover in the proximal direction;
• wherein:
• the cap comprises a plurality of retaining arms that restrict the movement of the needle cover in the proximal direction relative to the casing when the cap is attached to the casing and allow the movement of the needle cover in the proximal direction when the cap is detached from the casing;
• and
• the medicinal solution administration device further comprises a coupling mechanism that couples a proximal end of the needle cover and the drive unit to each other in an axial direction of the casing, wherein the coupling mechanism comprises:
• a first connection disposed on the sliding member, and
• a second connection disposed on the proximal end of the needle cover and coupled to the first connection, wherein:
• the second connection comprises a hole opened in a direction perpendicular to the axial direction of the casing, and
• the first connection comprises a protrusion protruding toward the second connection and engaged with the hole.