Vent plug and method

1. A vent plug for isolating a feature of a part having a surface defining an opening in the part, the vent plug comprising:

a plug having a first surface and a second surface spaced by a thickness and a radially outer surface engageable with the surface of the part to form an airtight seal therebetween, the plug including a bore having a diameter and extending between the first and second surfaces and a vent hole extending between the first and second surfaces;

a stem extending through the bore along an axis and having a first end, a second end and outer surface;

a cap interconnected to the stem, the cap including a sealing surface extending radially from the outer surface of the stem and overlapping the vent hole in the plug; and

a collar extending radially from the outer surface of the stem at a location spaced from the sealing surface of the stem by a distance, the distance being generally equal to the thickness between the first and second surfaces of the plug;

wherein;

the plug is captured between the cap and the collar; and

the collar is movable between a first position wherein the sealing surface is in engagement with the first surface of the plug so as to isolate an interior of the part and a second position wherein the collar compresses the second surface of the plug and the sealing surface is spaced from the first surface of the plug in response to the air pressure within the interior of the part.

2. The vent plug of claim 1 wherein the cap is interconnected to the first end of the stem.

3. The vent plug of claim 1 wherein the first surface of the plug includes a first portion, the bore and the vent hole intersecting the first portion of the first surface of the plug.

4. The vent plug of claim 3 wherein the thickness of the plug is a first thickness, the first thickness being the distance between the first portion of the first surface and the second surface of the plug.

5. The vent plug of claim 4 wherein the first surface of the plug includes a second portion extending radially outward from the first portion of the first surface of the plug, the second portion of the first surface and the second surface of the plug spaced by a second thickness less than the first thickness.

6. The vent plug of claim 1 wherein the plug includes a sidewall extending about an outer periphery of the plug, the sidewall defined by the outer surface of the plug and an inner surface projecting from the first surface of the plug.

7. The vent plug of claim 6 wherein:

the sidewall includes a terminal end axially spaced from the first surface of the plug; and

the sidewall including a flange extending radially outward from the terminal end.

8. A vent plug for isolating a feature of a part having a surface defining an opening in the part, the vent plug comprising:

a plug receivable in the opening to form an airtight seal between the plug and the surface of the part, the plug including first and second surfaces spaced by a thickness, a bore having a diameter and extending between the first and second surfaces and a vent hole extending between the first and second surfaces;

a stem receivable in the bore along an axis and including:

a cap having a sealing surface extending radially from an outer surface of the stem and overlapping the vent hole in the plug with the stem received in the bore; and

a collar extending radially from the outer surface of the stem at a location spaced from the sealing surface of the stem by a distance and being configured to capture the plug between the collar and the cap, the distance being generally equal to the thickness between the first and second surfaces of the plug;

wherein the collar is movable between a first position wherein the sealing surface is in engagement with the first surface of the plug so as to isolate an interior of the part and a second position wherein the collar compresses the second surface of the plug and the sealing surface is spaced from the first surface of the plug in response to the air pressure within the interior of the part.

9. The vent plug of claim 8 wherein the cap is interconnected to a first end of the stem.

10. The vent plug of claim 8 wherein the first surface of the plug includes a first portion, the bore and the vent hole intersecting the first portion of the first surface of the plug.

11. The vent plug of claim 10 wherein the thickness of the plug is a first thickness, the first thickness being the distance between the first portion of the first surface and the second surface of the plug.

12. The vent plug of claim 11 wherein the first surface of the plug includes a second portion extending radially outward from the first portion of the first surface of the plug, the second portion of the first surface and the second surface of the plug spaced by a second thickness less than the first thickness.

13. The vent plug of claim 10 wherein the plug includes a sidewall extending about an outer periphery, the sidewall including an outer surface engageable with the surface of the part and an inner surface projecting from the first surface of the plug.

14. The vent plug of claim 13 wherein:

the sidewall includes a terminal end axially spaced from the first surface of the plug; and

the sidewall including a flange extending radially outward from the terminal end.

15. A method for isolating a feature of a part having surface defining an opening in the part, the method comprising the steps of:

inserting a plug into the opening such that an airtight seal is formed between the plug and the surface of the part, the plug including first and second surfaces spaced by a thickness, a bore having a diameter and extending between the first and second surfaces and a vent hole extending between the first and second surfaces;

inserting a stem through the bore in the plug, the stem including:

a cap having a sealing surface extending radially from an outer surface of the stem and overlapping the vent hole in the plug; and

a collar extending radially from the outer surface of the stem at a location spaced from the sealing surface of the stem by a distance;

capturing the plug between the collar and the cap; and

moving the collar between a first position wherein the sealing surface is in engagement with the first surface of the plug and a second position wherein the collar compresses the second surface of the plug and the sealing surface is spaced from the first surface of the plug in response to the air pressure within the interior of the part.

16. The method of claim 15 wherein the distance between the collar and the sealing surface of the stem is generally equal to the thickness between the first and second surfaces of the plug.

17. The method of claim 15 wherein the cap is interconnected to a first end of the stem.

18. The method of claim 15 wherein:

the first surface of the plug includes a first portion, the bore and the vent hole intersecting the first portion of the first surface of the plug;

the thickness of the plug is a first thickness, the first thickness being the distance between the first portion of the first surface and the second surface of the plug; and

the first surface of the plug includes a second portion extending radially outward from the first portion of the first surface of the plug, the second portion of the first surface and the second surface of the plug spaced by a second thickness less than the first thickness.

19. The method of claim 15 wherein the plug includes a sidewall extending about an outer periphery, the sidewall including an outer surface engageable with the surface of the part and an inner surface projecting from the first surface of the plug.

20. The method of claim 19 wherein:

the sidewall includes a terminal end axially spaced from the first surface of the plug; and

the sidewall including a flange extending radially outward from the terminal end.