초록 ▼

A safe medical-drug injector with a collapsable plunger combination thereof is proposed. The injector includes a hub connected with a needle, a hollow barrel, and a collapsable plunger combination including a hollow cannula and a retractable plunger that is telescoped with the hollow cannula. At lea

A safe medical-drug injector with a collapsable plunger combination thereof is proposed. The injector includes a hub connected with a needle, a hollow barrel, and a collapsable plunger combination including a hollow cannula and a retractable plunger that is telescoped with the hollow cannula. At least a stress adjustable notch is formed at the core of the retractable plunger or in an upper edge of the hollow cannula, and at least one raised portion is formed on an outer lateral side of the retractable plunger near the stress adjustable notch to be correspondingly embedded with at least a depression formed on an inner lateral side of the hollow cannula. The engagement between the raised portion and the depression is released to make the retractable plunger drawn back to the hollow cannula when a following press is applied on the hollow cannula after the safe medical-drug injector completes an injection.

대표청구항 ▼

What is claimed is: 1. A safe medical-drug injector comprising: a needle hub connecting a needle; a hollow barrel connected with the needle hub for guiding the needle hub to be drawn back to the hollow barrel after an injection is completed; and a collapsable plunger combination inserted into the h

What is claimed is: 1. A safe medical-drug injector comprising: a needle hub connecting a needle; a hollow barrel connected with the needle hub for guiding the needle hub to be drawn back to the hollow barrel after an injection is completed; and a collapsable plunger combination inserted into the hollow barrel, the collapsable plunger combination comprising a hollow cannula and a retractable plunger, the hollow cannula comprising a first telescoping part and the retractable plunger comprising a second telescoping part, the first telescoping part telescoping with the second telescoping part, there being at least one raised portion formed on an outside wall of the second telescoping part to be correspondingly embedded in at least one depression formed on an inside wall of the first telescoping part, the raised portion and the depression engaging to each other; wherein the hollow cannula is formed with at least one stress adjustable notch on the upper edge, and wherein the engagement between the raised portion and the depression is released to make the retractable plunger drawn back to the hollow cannula when the stress adjustable notch deforms due to a following press on the hollow cannula after an injection is completed, and thereby spare space of the hollow barrel for accommodating the needle hub. 2. The safe medical-drug injector as set forth in claim 1, wherein the collapsable plunger combination is composed of the hollow cannula and the retractable plunger, and the hollow cannula and the retractable plunger are individually formed by injection molding. 3. The safe medical-drug injector as set forth in claim 1, wherein the raised portion comprises outward protruding dots one-piece formed on the outside wall of the retractable plunger. 4. The safe medical-drug injector as set forth in claim 1, wherein the raised portion comprises a plurality of adjacent rows of transversely convex annular ribs. 5. The safe medical-drug injector as set forth in claim 1, wherein the raised portion comprises a plurality of spaced rows of transversely convex annular ribs. 6. The safe medical-drug injector as set forth in claim 1, wherein the lower edge of the retractable plunger is a fillet edge. 7. The safe medical-drug injector as set forth in claim 1, wherein the outside wall of the retractable plunger is formed with a rough region above the raised portion. 8. The safe medical-drug injector as set forth in claim 1, wherein the upper edge on the inner side of the hollow cannula has a shape selected from the group consisting of arc, fillet and incline. 9. The safe medical-drug injector as set forth in claim 1, wherein the depression is selected from the group consisting of groove and cavity. 10. The safe medical-drug injector as set forth in claim 1, wherein the depression is selected from the group consisting of a plurality of adjacent rows of transversely concave annular ribs and a plurality of spaced rows of transversely concave annular ribs. 11. The safe medical-drug injector as set forth in claim 1, wherein the hollow cannula is formed with at least one exhausting hole on a sidewall far away from the first telescoping part. 12. The safe medical-drug injector as set forth in claim 1, wherein the hollow cannula is formed with a plurality of blocks near the lower part of the depression on the inside wall. 13. A safe medical-drug injector comprising: a needle hub connecting a needle; a hollow barrel connected with the needle hub for guiding the needle hub to be drawn back to the hollow barrel after an injection is completed; and a collapsable plunger combination inserted into the hollow barrel, the collapsable plunger combination comprising a hollow cannula and a retractable plunger, the hollow cannula comprising a first telescoping part and the retractable plunger comprising a second telescoping part, the first telescoping part telescoping with the second telescoping part, there being at least one raised portion formed on an outside wall of the second telescoping part to be correspondingly embedded in at least one depression formed on an inside wall of the first telescoping part, the raised portion and the depression engaging to each other; wherein the retractable plunger is formed with at least one stress adjustable notch on the core of the first telescoping part, and wherein the engagement between the raised portion and the depression is released to make the retractable plunger drawn back to the hollow cannula when a following press is applied on the hollow cannula after an injection is completed, and thereby spare space of the hollow barrel for accommodating the needle hub. 14. A safe medical-drug injector comprising: a needle hub connecting a needle; a hollow barrel connected with the needle hub for guiding the needle hub to be drawn back to the hollow barrel after an injection is completed; and a collapsable plunger combination inserted into the hollow barrel, the collapsable plunger combination comprising a hollow cannula and a retractable plunger, the hollow cannula comprising a first telescoping part and the retractable plunger comprising a second telescoping part, the first telescoping part telescoping with the second telescoping part, there being at least one raised portion formed on an outside wall of the second telescoping part to be correspondingly embedded in at least one depression formed on an inside wall of the first telescoping part, the raised portion and the depression engaging to each other; wherein the hollow cannula is formed with at least one stress adjustable notch on the upper edge of the first telescoping part, and wherein the engagement between the raised portion and the depression is released to make the retractable plunger drawn back to the hollow cannula when a following press is applied on the hollow cannula after an injection is completed, and thereby spare space of the hollow barrel for accommodating the needle hub.