US Patent 10398842 Rectangular syringe

An auto-injection syringe shaped similar to a credit card and having a biased injection mechanism operable to drive a needle into a user's body by a fixed distance to dispense a dose of fluid at a subcutaneous location. A safety may be provided to avoid undesired actuation of the injection mechanism. After the safety is bypassed, a trigger may be actuated by the user to allow operation of the injection mechanism. A reciprocating needle-cover resists casual view of the needle by the user during and after use of the syringe. A locking mechanism automatically holds the needle-cover at an extended position to isolate the needle from further contact and to resist re-use of the syringe.