Patent ID: 8597257

Claim:
A device for administering to an animal a fluid drug comprising: a housing having a housing open upper end and a housing bottom base defining an inner chamber; the housing bottom base having an aperture; the inner chamber adapted to slideably receive therein a reservoir chamber in an initial reservoir chamber position at a first predetermined distance from an interior surface of the housing bottom base, the reservoir chamber being confined to travel along a reservoir chamber travel path relative to the housing; wherein the reservoir chamber is held at the first predetermined distance by at least one releasable latch which interacts with a latch retainer on the housing open upper end, and wherein the latch includes a notch; the reservoir chamber defined by a reservoir chamber bottom base and surrounding wall extending from the reservoir bottom base so as provide a reservoir open top; the reservoir bottom base including a hollow needle having a lower end and an upper non-skin contacting end wherein the needle is mounted in and traverses the reservoir bottom base such that the upper non-skin contacting end is disposed within the interior of the reservoir chamber and just below a flexible filled reservoir body and the lower skin-contacting end can extend beyond the aperture to a second position at a predetermined distance defined by the reservoir chamber travel path of the reservoir chamber bottom base to the housing bottom base position along the reservoir chamber travel path relative the housing; the flexible filled reservoir body containing therein the fluid drug being located in the reservoir chamber near the reservoir open top and separated from the upper end of the hollow needle in the first predetermined reservoir chamber position; and an actuator having a plunger operably coupled thereto and terminating in a stopper; the latch being releasable from the latch retainer when pressure is applied to the actuator; the plunger adapted to be in slidable communication within the reservoir chamber via the reservoir open top such that, in use, the stopper can communicate with the reservoir body when in a second predetermined reservoir chamber position wherein a force being applied to the actuator causes the lower end of the hollow needle to enter the skin to the second position and further force causes the upper end of the hollow needle to pierce the reservoir body and puts the upper end of the needle into fluid communication with the contents of the reservoir body such that continuous force being applied to the actuator causes the fluid drug to be expelled through the hollow needle; the plunger including an indent for receiving therein a tab located on the reservoir chamber for maintaining the plunger depressed in the reservoir chamber after the fluid drug is expelled, and engagement of the tab in the indent causing the notch to engage with the latch when the reservoir chamber is returned to the initial position by biasing means whereby the needle is automatically retracted back into the housing in a locked position.