Retaining feature for corrugated acoustic duct
View Patent ↗A retaining feature is provided for connecting a plastic tube to a corrugated acoustic duct. The retaining feature accommodates variations in the undulations and thread pattern of the corrugated duct, while at the same time minimizing the materials, specialized equipment or tools, labor and cost of making a successful connection. The retaining feature includes at least one barb extending circumferentially around the exterior surface of the plastic tube. Each barb is sized and structured to engage an undulation of the corrugated duct.
1. A retaining feature for connecting a plastic tube to a corrugated acoustic duct commonly used in an automobile, the corrugated duct having a series of undulations defined by a set of ridges and grooves extending helically around the duct, the retaining feature comprising:
a plurality of barbs extending circumferentially around the exterior surface of the plastic tube along a helical path, each barb sized and structured to engage an undulation of the corrugated duct;
each barb having a thickness greater than or equal to an average width of a ridge; and
all of the barbs aligned along the helical path, the helical path spanning less than or equal to 360 degrees around the tube.
2. The retaining feature of claim 1 , wherein each barb has a thickness at least 150% greater that the average thickness of a ridge.
3. The retaining feature of claim 1 , wherein the plurality of barbs form a single thread extending once around the exterior surface of the plastic tube.
4. The retaining feature of claim 1 , wherein each barb has a height greater than a height of the ridge, each barb pressing against the interior surface of the corrugated duct.
5. The retaining feature of claim 1 , wherein each barb includes a leading edge and a trailing edge defined by the relative rotation of the tube and corrugated duct during assembly, the leading edge oriented at an angle less than or equal to 45 degrees to facilitate assembly of the tube and corrugated duct.
6. The retaining feature of claim 1 , wherein each barb includes a leading edge and a trailing edge defined by the relative rotation of the tube and corrugated duct during assembly, the trailing edge oriented at an angle of about 90 degrees to hamper disassembly of the tube and corrugated duct.
7. The retaining feature of claim 1 , wherein each barb extends circumferentially around the tube at a helical angle of about the average helical angle of the undulations of the corrugated duct.
8. The retaining feature of claim 1 , wherein each barb spans about 10 degrees to about 35 degrees circumferentially around the tube.
9. A retaining feature for connecting a plastic tube to a corrugated acoustic duct commonly used in an automobile, the corrugated duct having a series of undulations defined by a set of ridges and grooves extending helically around the duct, the retaining feature comprising:
four barbs extending around the exterior surface of the plastic tube along a helical path, each barb sized and structured to engage an undulation of the corrugated duct;
each barb including a leading edge and a trailing edge defined by the relative rotation of the tube and corrugated duct during assembly, the trailing edge oriented at an angle of about 90 degrees to hamper disassembly of the tube and corrugated duct, the leading edge being oriented at an angle less than or equal to 45 degrees to facilitate assembly of the tube and corrugated duct,
the four barbs aligned along the helical path and, in combination, spanning no more than about one revolution around the plastic tube.
10. The retaining feature of claim 9 , wherein each barb has a width greater than an average width of a ridge.
11. The retaining feature of claim 9 , wherein each barb has a width at least 150% greater that the average width of a ridge.
12. The retaining feature of claim 9 , wherein each barb has a height greater than the height of a ridge.
13. The retaining feature of claim 9 , wherein each barb has a height greater than a height of the ridge, each barb pressing against the interior surface of the corrugated duct.
14. The retaining feature of claim 9 , wherein each barb extends circumferentially around the tube at a helical angle of about the average helical angle of the undulations of the corrugated duct.
15. The retaining feature of claim 9 , wherein each barb spans about 10 degrees to about 35 degrees circumferentially around the tube.
16. A retaining feature for connecting a plastic tube to a corrugated acoustic duct commonly used in an automobile, the corrugated duct having a series of undulations defined by a set of ridges and grooves extending helically around the duct, the retaining feature comprising:
a first barb extending along a helical path around the exterior surface of the plastic tube;
a second barb extending along the helical path around the exterior surface of the plastic tube;
the first and second barb sized and structured to engage an undulation of the corrugated duct; and
all of the barbs being aligned along the helical path that spans less than or equal to one revolution around the plastic tube.
17. The retaining feature of claim 16 , wherein the helical path is oriented at an angle of about the average helical angle of the undulations of the corrugated duct.
18. The retaining feature of claim 16 , wherein the first and second barbs extend circumferentially around the tube different distances.
19. The retaining feature of claim 18 , wherein the first barb spans about 10 degrees, and the second barb spans about 35 degrees.
20. The retaining feature of claim 16 , further comprising a third barb and a fourth barb extending circumferentially around the exterior surface of the plastic tube, the first, second, third and fourth barbs being equidistantly spaced around the tube.
21. The retaining feature of claim 20 , wherein first barb Is diametrically opposed to the third barb, and wherein the second barb is diametrically opposed to the fourth barb, and wherein the first and third barbs extend circumferentially a distance different than the distance the second and fourth barbs extend circumferentially.
22. The retaining feature of claim 16 , wherein each barb includes a leading edge and a trailing edge defined by the relative rotation of the tube and corrugated duct during assembly, the leading edge oriented at an angle less than or equal to 45 degrees to facilitate assembly of the tube and corrugated duct.
23. The retaining feature of claim 16 , wherein each barb includes a leading edge and a trailing edge defined by the relative rotation of the tube and corrugated duct during assembly, the trailing edge oriented at an angle of about 90 degrees to hamper disassembly of the tube and corrugated duct.
24. The retaining feature of claim 16 , wherein each barb has a width greater than an average width of a ridge.
25. The retaining feature of claim 16 , wherein each barb has a width at least 150% greater that the average width of a ridge.
26. The retaining feature of claim 16 , further comprising at least one stop wall projecting radially from the tube, the stop wall having an axially facing surface to limit the amount of overlap of the corrugated duct and tube.
27. The retaining feature of claim 26 , wherein each stop wall has a height greater than a height of the first and second barbs.