Plastic fastener

1. A fastener for removably mounting a mounting object having an insertion rib into a mounting aperture formed on a panel, the fastener comprising

a fastener body comprising a pair of legs extending in parallel, each leg having one fixed end and one free end, and a shoulder portion causing the legs to be elastically engaged with inner edges of the mounting aperture when the fastener is inserted into the mounting aperture of the panel;

a gripper portion including a pair of gripper arms extending from an inner side of the fastener body, and interposing the insertion rib between a pair of opposite gripper surfaces of the pair of gripper arms when the fastener is fitted to the insertion rib; and

an engagement projection formed on any one of the pair of gripper surfaces and extending from one of the pair of gripper surfaces toward the other one of the pair of gripper surfaces to a height exceeding half of the distance between the pair of gripper surfaces so as to engage with an engagement slot formed on the insertion rib, the other gripper arm opposite to the engagement projection including a recess and a bulge formed continuously in a direction extending from the recess, the recess and the bulge formed from the other one of the pair of gripper surfaces, and thereby the entire other gripper arm having an S shape, the recess being aligned with the engagement projection.

2. The fastener of claim 1 , wherein each end of the pair of gripper arms opposite to the fastener body includes a tapered guide for guiding the insertion rib to be positioned between the pair of gripper arms.

3. The fastener of claim 1 , wherein the engagement projection comprises a first inclined projection surface guiding the insertion rib to be inserted, and a second projection surface engaged to the engagement slot when the insertion rib is interposed between the pair of gripper arms.

4. The fastener of claim 3 , wherein the second projection surface has a downward slant toward one of the gripper arms.

5. The fastener of claim 1 , wherein the height of the engagement projection is more than 80% of a depth of the engagement slot.

6. The fastener of claim 1 , further comprising a stabilizer formed on the free end of each leg and protruding outwardly so as to be elastically supported on an outer surface of the panel when the fastener is inserted into the mounting aperture.

7. The fastener according to claim 1 , wherein the engagement projection is spaced from a free end of the gripper arm on which the engagement projection is formed.

8. The fastener assembly according to claim 1 , wherein each of the gripper arms has one end fixed with the fastener body and one free end.

9. A fastener assembly comprising

a fastener for removably mounting a mounting object,

a panel including a mounting aperture into which the fastener is inserted; and

a mounting object including an insertion rib interposed between a pair of opposite gripper surfaces of the fastener,

wherein the fastener removably mounts the mounting object into the mounting aperture formed on the panel, and

wherein the fastener comprises:

a fastener body comprising a pair of legs extending in parallel, each leg having one fixed end and one free end, and a shoulder portion causing the legs to be elastically engaged with inner edges of the mounting aperture when the fastener is inserted into the mounting aperture of the panel;

a gripper portion including a pair of gripper arms extending from an inner side of the fastener body, and interposing the insertion rib between a pair of opposite gripper surfaces of the pair of gripper arms when the fastener is fitted to the insertion rib; and

an engagement projection formed on any one of the pair of gripper surfaces and extending from one of the pair of gripper surfaces toward the other one of the pair of gripper surfaces to a height exceeding half of the distance between the pair of gripper surfaces so as to engage with an engagement slot formed on the insertion rib, the other gripper arm opposite to the engagement projection including a recess and a bulge formed continuously in a direction extending from the recess, the recess and the bulge formed from the other one of the pair of gripper surfaces, and thereby the entire other gripper arm having an S shape, the recess being aligned with the engagement projection.

10. The fastener assembly according to claim 9 , wherein each end of the pair of gripper arms opposite to the fastener body includes a tapered guide for guiding the insertion rib to be positioned between the pair of gripper arms.

11. The fastener assembly according to claim 9 , wherein the engagement projection comprises a first inclined projection surface guiding the insertion rib to be inserted, and a second projection surface engaged to the engagement slot when the insertion rib is interposed between the pair of gripper arms.

12. The fastener assembly according to claim 11 , wherein the second projection surface has a downward slant toward one of the gripper arms.

13. The fastener assembly according to claim 9 , wherein the height of the engagement projection is more than 80% of a depth of the engagement slot.

14. The fastener assembly according to claim 9 , further comprising a stabilizer formed on the free end of each leg and protruding outwardly so as to be elastically supported on an outer surface of the panel when the fastener is inserted into the mounting aperture.

15. The fastener according to claim 9 , wherein the engagement projection is spaced from a free end of the gripper arm on which the engagement projection is formed.

16. The fastener assembly according to claim 9 , wherein each of the gripper arms has one end fixed with the fastener body and one free end.