Needle insertion and retraction mechanism

A system for shielding a needle of an injection device during removal from an injection site:

• a housing having a chassis and a mounting plate pivotably attached to the chassis;
• a base movably mounted to the chassis and including a contact surface having an adhesive for attachment to an injection zone;
• the needle being mounted on the mounting plate and a needle tip thereof being movable between an exposed position, wherein the needle tip projects outwardly from the housing, and a shielded position, wherein the needle tip is retracted within the housing;
• the mounting plate being movable between a first position, positioning the needle tip in the exposed position thereof, and a second position, positioning the needle tip in the shielded position thereof, in which the mounting plate is further distanced from said contact surface relative to the first position, and the base being movable between an extended position extended away from the chassis and a collapsed position collapsed against the chassis;
• and a lock operatively engaging the mounting plate in said first position of the mounting plate and said collapsed position of said base, inhibiting movement of said needle tip from the exposed position thereof to the shielded position thereof, wherein movement of said base from the collapsed position to the extended position disengages said lock from said mounting plate to allow movement of said needle tip from said exposed position to said shielded position.