Strain relief boot with flexible extension for guiding fiber optic cable

• US 20040234209A1
• Filed: 05/22/2003
• Published: 11/25/2004
• Est. Priority Date: 05/22/2003
• Status: Active Grant

• Current Assignee: 3M Innovative Properties Company (3M Company)
• Original Assignee: 3M Innovative Properties Company (3M Company)
• Inventors: Lurie, Edward B., Cox, Larry R., Matthies, Mark D., Loder, Harry A.
• Granted Patent: US 7,001,081 B2
• Time in Patent Office: Days
• US Class Current: 385/86
• CPC Class Codes: G02B 6/38875 Protection from bending or twisting

Abstract

The present invention relates to a fiber optic cable assembly comprising (a) a connector subassembly comprising a fiber optic cable terminated in a connector, the fiber optic cable having a minimum bend radius; and (b) a strain relief boot attached to the connector subassembly, the strain relief boot comprising a core portion, a flexible extension having a proximal end and a distal end, the proximal end extending from the core portion, and a means for retaining at least a portion of the fiber optic cable which is disposed along the flexible extension. The flexible extension does not have a predetermined bend.

Claims

1. A fiber optic cable assembly comprising:

(a) a connector subassembly comprising a fiber optic cable terminated in a connector, the fiber optic cable having a minimum bend radius; and

(b) a strain relief boot attached to the connector subassembly, the strain relief boot comprising a core portion, a flexible extension having a proximal end and a distal end, the proximal end extending from the core portion, and a means for retaining at least a portion of the fiber optic cable which is disposed along the flexible extension;

wherein the flexible extension does not have a predetermined bend.

2. The fiber optic cable assembly of claim 1, wherein the flexible extension is a tapered beam having a varying cross-sectional area such that the height of the tapered beam at the proximal end is about twice the height of the tapered beam at the distal end.

3. The fiber optic cable assembly of claim 1, wherein the strain relief boot and the flexible extension are formed integrally.

4. The fiber optic cable assembly of claim 1, wherein the flexible extension is a removable member comprising a collar at its proximal end, the collar being attached to the core portion of the strain relief boot.

5. The fiber optic cable assembly of claim 1, wherein the strain relief boot is repositionable or non-repositionable.

6. The fiber optic cable assembly of claim 5, wherein the repositionable or the non-repositionable strain relief boot further comprises a connector mating end attached to the end of the core portion that is the opposite of the end from which the flexible extension extends.

7. The fiber optic cable assembly of claim 6, wherein the repositionable strain relief boot has a longitudinal axis along its length and further comprises:

(a) a plurality of slits in the core portion, the slits disposed generally perpendicular to the longitudinal axis; and

(b) a rib extending from the core portion, the rib having a wire disposed therein.

8. The fiber optic cable assembly of claim 7, wherein the rib is formed integrally with the strain relief boot.

9. The fiber optic cable assembly of claim 7, wherein the wire is molded in place in the rib.

10. The fiber optic cable assembly of claim 1, wherein the means for retaining a fiber optic cable is selected from a group consisting of open loops, closed loops, and combination thereof.

11. The fiber optic cable assembly of claim 10 having two flexible extensions extending from the core portion of the strain relief boot, the flexible extensions disposed parallel to one another.

12. The fiber optic cable assembly of claim 11, wherein the two flexible extensions are connected by at least one closed loop.

13. The fiber optic cable assembly of claim 1, wherein the flexible extension is made from a material selected from a group consisting of polymeric material, a metallic material, or combination thereof.

14. The fiber optic cable assembly of claim 13, wherein the polymeric material is selected from the group consisting of polyurethane and a terpolymer elastomer made from ethylene-propylene diene monomer.

15. The fiber optic cable assembly of claim 1, wherein the flexural characteristic of the flexible extension coincides with the flexural characteristic of the fiber optic cable used.

16. The fiber optic cable assembly of claim 1, wherein the core portion of the strain relief boot is tapered.

17. The fiber optic cable assembly of claim 1, wherein the length of the flexible extension is about one third of the total length of the strain relief boot.

18. The fiber optic cable assembly of claim 1, wherein the flexible extension is bent at a constant radius of curvature.

19. The fiber optic cable assembly of claim 1, wherein the flexible extension provides stress relief to the fiber optic cable exiting the core portion.

20. The fiber optic cable assembly of claim 13, wherein the polymeric material meets UL-94 V0 rating requirements.

21. The fiber optic cable assembly of claim 1, wherein when a tensile stress is applied to the fiber optic cable, the flexible extension deflects in substantially a constant radius of curvature in response to that stress.

22. The fiber optic cable assembly of claim 21, wherein the constant radius of curvature at which the flexible extension deflects is not less than the minimum bend radius of the fiber optic cable.

23. The fiber optic cable assembly of claim 1, wherein the fiber optic cable is a single or multifiber cable.

24. A strain relief boot for use with a fiber optic cable having a minimum bend radius, the strain relief boot comprising:

(a) a core portion; and

(b) a flexible extension having a proximal end and a distal end, the proximal end extending from the core portion; and

(c) means for retaining at least a portion of the fiber optic cable which is disposed along the flexible extension,

wherein the flexible extension does not have a predetermined bend.

25. The strain relief boot of claim 24, wherein the flexible extension is a tapered beam having a varying cross-sectional area such that the height of the tapered beam at the proximal end is about twice the height of the tapered beam at the distal end.

26. The strain relief boot of claim 24, wherein the strain relief boot and the flexible extension are formed integrally.

27. The strain relief boot of claim 24, wherein the flexible extension is a removable member comprising a collar at its proximal end, the collar being attached to the core portion.

28. The strain relief boot of claim 24, wherein the strain relief boot is repositionable or non-repositionable.

29. The strain relief boot of claim 28, wherein the repositionable or the non-repositionable strain relief boot further comprises a connector mating end attached to the end of the core portion that is the opposite of the end from which the flexible extension extends.

30. The strain relief boot of claim 29, wherein the repositionable strain relief boot has a longitudinal axis along its length and further comprises:

(a) a plurality of slits in the core portion, the slits disposed generally perpendicular to the longitudinal axis; and

(b) a rib extending from the core portion, the rib having a wire disposed therein.

31. The strain relief boot of claim 30, wherein the rib is formed integrally with the strain relief boot.

32. The strain relief boot of claim 30, wherein the wire is molded in place in the rib.

33. The strain relief boot of claim 24, wherein the means for retaining a fiber optic cable is selected from a group consisting of open loops, closed loops, and combination thereof.

34. The strain relief boot of claim 33 having two flexible extensions extending from the core portion, the flexible extensions disposed parallel to one another.

35. The strain relief boot of claim 34, wherein the two flexible extensions are connected by at least one closed loop.

36. The strain relief boot of claim 24, wherein the flexible extension is made from a material selected from a group consisting of polymeric material, a metallic material, or combination thereof.

37. The strain relief boot of claim 36, wherein the polymeric material is selected from the group consisting of polyurethane and a terpolymer elastomer made from ethylene-propylene diene monomer.

38. The strain relief boot of claim 24, wherein the flexural characteristic of the flexible extension coincides with the flexural characteristic of the fiber optic cable used.

39. The strain relief boot of claim 24, wherein the core portion is tapered.

40. The strain relief boot of claim 24, wherein the length of the flexible extension is about one third of the total length of the strain relief boot.

41. The strain relief boot of claim 24, wherein the flexible extension is bent at a constant radius of curvature.

42. The strain relief boot of claim 24, wherein the flexible extension provides stress relief to the fiber optic cable exiting the core portion.

43. The strain relief boot of claim 37, wherein the polymeric material meets UL-94 V0 rating requirements.

44. The strain relief boot of claim 24, wherein when a tensile stress is applied to the fiber optic cable, the flexible extension deflects in substantially a constant radius of curvature in response to that stress.

45. The strain relief boot of claim 44, wherein the constant radius of curvature at which the flexible extension deflects is not less than the minimum bend radius of the fiber optic cable.