Spiral flex tree fastener

• US 5,468,108 A
• Filed: 09/12/1994
• Issued: 11/21/1995
• Est. Priority Date: 09/12/1994
• Status: Expired due to Term

• Current Assignee: Illinois Tool Works Inc.
• Original Assignee: Illinois Tool Works Inc.
• Inventors: Peek, Brian R., Sullivan, Kathleen A.
• Primary Examiner(s): Wilson, Neill R.
• Application Number:
  US08/304,154
• Time in Patent Office: 435 Days
• Field of Search: 411/508, 411/509, 411/510, 411/908, 411/913
• US Class Current: 411/510
• CPC Class Codes: F16B 21/084 with a series of flexible ribs or fins extending laterally from the shank of the stud, pin or spigot, said ribs or fins deforming predominantly in a direction parallel to the direction of insertion of the shank
• CPC Class Codes: Y10S 411/908 Resinous material
• CPC Class Codes: Y10S 411/913 Self-expanding anchor

Abstract

A spiral flex tree fastener, for use in securing a component to a panel by insertion into a hole provided therein, has a head, and a shank extending axially therefrom and ending in a conical rounded point. The head, shank, and point share a common axis, the head naturally being of greater diameter than the shank and point. The point has a maximum diameter substantially equal to the hole into which the fastener may be inserted. The shank is flattened, has two sides and a flange running axially along each of the two sides. The shank has a diagonally measured width equivalent to the maximum diameter of the point and merges smoothly thereinto, and the flanges ensure that the fastener remains centered in the appropriately sized hole into which it may be inserted. On each side of the shank are a plurality of flexible fins set at an oblique angle with respect to the axis of the fastener. A portion of each fin extends radially outward from the axis of the shank beyond the radial extent of the conical rounded point. The fins flex against the walls of the appropriately sized hole, securing the fastener therein, and are shaped to make its nondestructive withdrawal, if desired or necessary, possible but more difficult to effect than its original insertion.

Claims

1. A spiral flex tree fastener for removable insertion into a hole defined within a panel, comprising:

a head;

an elongated shank having a longitudinal axis and extending axially from said head; and

two sets of substantially planar, flexible fins disposed upon opposite sides of said elongated shank, said flexible fins being disposed parallel to each other within each one of said sets of fins, each one of said sets of fins extending axially along said elongated shank, each one of said fins within each one of said sets of fins being disposed at a predetermined angle with respect to said longitudinal axis of said elongated shank such that said fins within said two sets of fins together define spiral loci about said fastener shank and about said longitudinal axis of said fastener shank, and each one of said flexible fins having a radial extent which is greater than the radial distance extending between an edge portion of said hole and said longitudinal axis of said elongated shank so that when said fastener is inserted into said hole, said flexible fins will flex against the walls of said panel defining said hole so as to hold said fastener therein.

2. A spiral flex tree fastener as claimed in claim 1, wherein:

each one of said flexible fins within each one of said sets of fins has an upper end and a lower end, said upper end of each one of said flexible fins being closer to said head than said lower end of each one of said flexible fins; and

wherein a portion of each one of said flexible fins, having said radial extent which is greater than said radial distance extending from said edge portion of said hole to said longitudinal axis of said elongated shank, is closer to said upper end than to said lower end.

3. A spiral flex tree fastener as claimed in claim 1 wherein said head comprises a lower resilient head portion adjacent to said elongated shank and an upper head portion connected to but axially spaced from said lower head portion.

4. A spiral flex tree fastener as claimed in claim 1 wherein said elongated shank narrows to a point at an end opposite to said head.

5. A spiral flex tree fastener as claimed in claim 1 wherein said elongated shank has a flattened cross section.

6. A spiral flex tree fastener as claimed in claim 1 wherein at least one of said two sides of said elongated shank further comprises an axially extending flange.

7. A spiral flex tree fastener as claimed in claim 1 further comprising a conical rounded point at an end of said elongated shank which is disposed opposite from said head.

8. A spiral flex tree fastener as claimed in claim 1 wherein said elongated shank has a cross section whose maximum extent is substantially equal to the maximum extent of said hole, so that said elongated shank may fit snugly in said hole when inserted therein and said axis of said elongated shank may remain at a fixed distance relative to the center of said hole.

9. A spiral flex tree fastener as set forth in claim 1, wherein:

each one of said fins has an insertion leading edge portion which defines a predetermined angle with respect to said longitudinal axis of said elongated shank so as to predetermine the insertion force characteristic of said fastener.

10. A spiral flex tree fastener as set forth in claim 1, wherein:

each one of said fins has a removal force leading edge portion which defines a predetermined angle with respect to said longitudinal axis of said elongated shank so as to predetermine the removal force characteristic of said fastener.

11. A spiral flex tree fastener as set forth in claim 1, wherein:

each one of said sets of fins comprises eight fins.

12. A spiral flex tree fastener as set forth in claim 1, wherein:

each one of said sets of fins comprises six fins.

13. A spiral flex tree fastener as set forth in claim 1, wherein:

said fastener is fabricated from a polymeric resin.

14. A spiral flex tree fastener for removable insertion into a hole defined within a panel, comprising:

a head;

an elongated shank having a longitudinal axis and extending axially from said head; and

two sets of substantially planar, flexible fins disposed upon opposite sides of said elongated shank, said flexible fins being disposed parallel to each other within each one of said sets of fins, each one of said sets of fins extending axially along said elongated shank, each one of said fins within each one of said sets of fins being disposed at a predetermined angle with respect to said longitudinal axis of said elongated shank such that the intersection of each one of said fins with said elongated shank defines a locus which is disposed at a predetermined oblique angle with respect to said longitudinal axis of said elongated shank, and each one of said flexible fins has a radial extent which is greater than the radial distance defined between an edge portion of said hole and said longitudinal axis of said elongated shank so that when said fastener is inserted into said hole, said flexible fins will flex against the walls of said panel defining said hole so as to retain said fastener therein.

15. A spiral flex tree fastener as set forth in claim 14, wherein:

said elongated shank has a rounded conical end opposite said head.

16. A spiral flex tree fastener as set forth in claim 14, wherein:

each one of said flexible fins within each one of said sets of fins has an upper end and a lower end wherein said upper end of each one of said flexible fins is disposed closer to said head than said lower end of each one of said flexible fins.

17. A spiral flex tree fastener as set forth in claim 14, wherein:

said elongated shank has a flattened cross-sectional configuration.

18. A spiral flex tree fastener as set forth in claim 14, further comprising:

axially extending flange means integrally formed upon opposite sides of said elongated shank for engaging sidewall portions of said hole defined within said panel so as to maintain said fastener substantially centered within said hole of said panel.

19. A spiral flex tree fastener as set forth in claim 14, wherein:

each one of said fins has an insertion leading edge portion which defines a predetermined angle with respect to said longitudinal axis of said elongated shank so as to predetermine the insertion force characteristic of said fastener.

20. A spiral flex tree fastener as set forth in claim 14, wherein:

each one of said fins has a removal force leading edge portion which defines a predetermined angle with respect to said longitudinal axis of said elongated shank so as to predetermine the removal force characteristic of said fastener.