Patent attributes
A catheter insertion device includes a hollow needle attached to a needle base. A compression spring mechanically biases the needle base away from a plunger. A catheter is configured to be contactable by the plunger when the plunger moves in a forward direction. An expandable chamber is in fluidic and/or pneumatic communication with the hollow needle. The plunger inserts the catheter when a vacuum formed in the expandable chamber by the compression spring pushing the plunger away from the needle base is released by a fluid and/or a gas entering the hollow needle at a distal skin-piercing end as it punctures a vein or artery. A generally hollow housing includes an annularly-shaped seal relief formed as an inside surface where in a stored position a second circumferential seal captured by the plunger is not in contact with the inside surface of the generally hollow housing.