WO2010115095A1

WO2010115095A1 - Cap for muffler mounting tube and muffler having same

Info

Publication number: WO2010115095A1
Application number: PCT/US2010/029770
Authority: WO
Inventors: John Michelon
Original assignee: John Michelon
Priority date: 2009-04-02
Filing date: 2010-04-02
Publication date: 2010-10-07
Also published as: WO2010115095A8

Abstract

The present disclosure is directed to a cap for closing the open end of a muffler mounting tube and a muffler having such a cap The cap can include a tab to engage a groove on the mounting tube to retain the cap to the mounting tube The tab can be connected to a spring arm to bias the tabs when inserting the cap in the mounting tube The cap can also include a pry slot to assist in removal of the cap The spring arm and tab can be cut from a cover portion of the cap to form the pry slot In another embodiment, the cap can have a cover portion and a body portion The cap and body can be separate pieces connected attached to each other or formed as one integral piece

Description

CAP FOR MUFFLER MOUNTING TUBE AND MUFFLER HAVING SAME

This application claims the benefit of U.S. Provisional Application Serial No. 61/166,201 filed on April 2, 2009, the disclosure of which is incorporated in its entirety herein by reference.

BACKGROUND

[0001] The present disclosure is directed generally to caps for closing muffler mounting tubes. In particular, the present disclosure is directed to caps for closing the openings of muffler mounting tubes that have a circumferential groove on the interior surface of the tube. Such mufflers are used on chainsaws or other hand tools having an internal combustion engine.

[0002] Mufflers for internal combustion engines of chainsaws or other hand tools are typically attached to the internal combustion engine with bolts or screws. Typically such mufflers have one or more, typically two, mounting sleeves or tubes which pass through the muffler to allow access to the mounting fasteners. As the muffler and in particular the internal ends of the mounting tubes are in contact with the internal combustion engine, a significant amount of heat can build in the mounting tubes. Debris entering the open ends of the mounting tubes can ignite and can create a fire hazard.

[0003] Secondary plates have typically been used to prevent entry of debris into the mounting tubes. The secondary plate does not close off the mounting tubes but rather obstructs a direct path into the mounting tubes. Also, secondary plates tend to be bulky, costly and can add considerable difficulty in servicing the muffler.

SUMMARY

[0004] In one aspect of the present disclosure a muffler is provided. The muffler includes a mounting tube for mounting the muffler to an internal combustion engine and a cap for closing off the open end of the mounting tube. The mounting tube includes a groove at an open end thereof and the cap includes a cover and a tab for engaging the groove to retain the cap to the mounting tube.

[0005] In another aspect of the present disclosure a cap is provided for closing off the open end of a muffler mounting tube having a groove adjacent the open end. The cap includes a cover for closing the open end of the mounting tube and at least one tab for engaging the groove to retain the cover to the mounting tube. BRIEF DESCRIPTION OF THE DRAWINGS

[0006] In the following detailed description, reference will frequently be made to the following views of the drawing, in which like reference numerals refer to like components, and in which:

[0007] Fig. 1 is a perspective view of one embodiment of a muffler and tube caps according to the present disclosure;

[0008] Fig. 1 A is a cross-section view taken at line 1 A-1A of Fig. 1 ;

[0009] Fig. 2 is a cross-sectional view of one embodiment of a tube cap of the present disclosure;

[0010] Fig. 3 is a cross-sectional view of the tube cap shown in Fig. 2 fitted to a mounting tube;

[0011] Fig. 4 is a cross-sectional view of another embodiment of a tube cap of the present disclosure;

[0012] Fig. 5 is a cross-sectional view of another embodiment of a tube cap according to the present disclosure fitted to a mounting tube;

[0013] Fig. 6 is a top side perspective view of another embodiment of a tube cap according to the present disclosure;

[0014] Fig. 7 is a bottom side perspective view of the tube cap shown in Fig. 6;

[0015] Fig. 8 is a magnified cross-sectional view of the tube cap shown in Fig. 9; and

[0016] Fig. 9 is a cross-sectional view another embodiment of a tube cap according to the present disclosure.

DETAILED DESCRIPTION

[0017] It is to be understood that the disclosed embodiments are merely exemplary of the disclosure, which may be embodied in various forms. Therefore, specific details disclosed herein are not to be interpreted as limiting, but merely as a representative basis for teaching one skilled in the art to variously employ the inventive features herein disclosed in virtually any appropriate manner and combination.

[0018] The cap can have a cover portion to close off access opening of the mounting tube and one or more tabs to engage the mounting tube and retain the cap to the mounting tube. The tabs can be on the cover portion or can be on another portion of cap 10. [0019] Figs. 1 and 1 A show one embodiment of tube cap 10 for sealing off mounting tubes 12 of muffler 14. Muffler 14 shown in Figs. 1 and 1 A is a chainsaw muffler but tube cap 10 can be used for covering the access openings of mounting tubes of other muffler types, such as small engine mufllers. The outer end of mounting tubes 12 can have flange 16 circumscribing access opening 17. Flange 16 can have outer surface 18 and mounting tube 12 can have groove 19 on its inner surface 20 and adjacent flange 16.

[0020] As shown in Fig. 2, cap 10 can have cover portion 22, body portion 24 and one or more tabs 26. Body 24 can be shaped and dimensioned to extend into mounting tube 12 and cover portion 22 can be shaped and dimensioned to close off opening 17 of mounting tube 12. One or more tabs 26 can engage groove 19 to retain cap 10 to mounting tube 10. Cap 10 can be made of a variety of strong but malleable materials which can resist temperatures of up to about 900° F. such as metal or metal alloys. In one embodiment, cap 10 is made of aluminum and in another is made of steel and can be formed from a solid piece of sheet metal by stamping processes.

[0021] Cover portion 22 can have a generally flat central panel 28 and an annular lip 30 raised relative to panel 28 and circumscribing central panel 28. Alternatively, cover portion 22 can have other configurations and even generally flat throughout. The outer end of lip 30 can be folded over itself to form mating channel 32 which can receive a complementary mating member of body portion 24 to connect the cover portion 22 and body portion 24 together. In the embodiment shown in Fig. 2, channel 32 is in line or at about the same elevation as panel 28. [0022] Body portion 24 can have a cylindrical sidewall 34. Sidewall 34 can have an outwardly flared neck portion 36 at an end thereof. The terminal end 38 of neck portion 36 can be received in and engage with mating channel 32 to secure body portion 24 to cap 22. As will be described below with respect to another embodiment of the present disclosure, the cover potion 22 and body portion 24 can be a unitary piece.

[0023] Body portion can have one or more tabs 26 to engage mounting tube 1 12 for retaining cap 10 to mounting tube 12. In the embodiment shown in Fig. 3, cap 10 can have three tabs 26 spaced equidistant from each other about sidewall 34. More or fewer tabs 26 can be used depending on the application. For example, more tabs can be utilized when the muffler is exposed to high or extreme vibrations and/or the configuration of groove 19 does not provide a secured enough engagement. [0024] Tabs 26 can extend from sidewall 34 and can be positioned along sidewall 34 such that tabs 26 engage groove 19 when lip 32 engages flange 16 as shown in Fig. 3. Tabs 26 can extend out from sidewall 34 such that there is tight frictional engagement with groove 19. The degree to which tabs 26 extend from sidewall 34 is dependent upon the spacing between sidewall 34 and inner surface 35 of mounting tube 12, and the degree of frictional engagement between tabs 26 and groove 19 desired. To provided additional degree of freedom as to how far tabs 26 can extend to allow adequate frictional engagement while making cap 10 easy to install in mounting tube 12, tabs 26 can be made of a resilient material and/or connected to resilient members such that tabs 26 can move inwardly, i.e. out of engagement during application of cap 10 to mounting tubes 12 and back into engagement after cap 10 is installed on mounting tube 12.

[0025] In one embodiment tabs 26 can have biasing members to allow the tabs to resiliently engage groove 19 of mounting tubes 12. In the embodiments illustrated In Figs. 1 -3, tabs 26 can be supported by spring arms 40. Tabs 26 and spring arms 40 can be separately connected parts or integrally formed. In the illustrated embodiments of Figs. 1 -3 tabs 26 and spring arms 40 can be integrally formed from sidewall 34. Spring arms 40 allow tabs 26 to move inwardly as cap 10 is inserted in mounting tube 12 and to return to a position to engage groove 19. A portion of sidewall 34 can be removed to form the tabs 26 and spring arms 40 with tabs 26 angled or bent out of the plane defined by sidewall 34. This can be accomplished many means such by stamping processes or direct molding. Alternatively, a separate tab or spring arm and tab can be attached to sidewall.

[0026] Figs. 2 and 4 illustrate two different embodiments of tabs 26. The far edge or engaging end of tabs 26 can either have a flat surface or profile 44 as shown Fig. 4 or an arched or arcuate surface or profile 42 as shown in Fig. 2. Arcuate profile 42 can be concave shaped such that central portion 45 is spaced below the outer ends or corners 47 of tab 26. It has been found that corners 47 can improve the engagement of tab 26 to groove 19 and may be desirable in high vibration conditions and/or when depth or configuration of groove 19 provides less than adequate engagement with tabs 26 having flat surface 44. In one embodiment cap 10 can have one or more tabs 26 having flat surface 44 and one or more tabs 26 having curved or arcuate surface 42.

[0027] Another embodiment of cap 1 10 is shown in Fig. 5. Cap 1 10 can have the same general features (and given like reference numerals) as discussed above with respect to cap 10 except that cover portion 122 and body portion 124 can be one integral piece of material. In other words, cover portion 122 and body portion 124 can have a one piece construction. The wall forming cover portion 122 can be folded over itself to form lip 130, neck portion 136 and can then extend generally perpendicularly relative to panel 128 to form sidewall 134. Spring arm 140 and tabs 126 can also be formed out of sidewall 134 or attached as separate pieces as discussed with respect to cap 10. Cap 1 10 can be formed using known stamping, molding and other metal working methods.

[0028] Figs. 6 and 7 show another embodiment of cap 210. Cap 210 can have central panel 228 and annular lip 230 raised relative to panel 228. Annular sidewall 234 can connect central panel 228 to annular lip 230. Cap 210 can have one or more tabs 226 extending beyond the radial extent of sidewall 234 for engaging groove 19 of mounting tube 12 shown in Figs. 8 and 9. Tabs 226 can also have either arcuate ends 242 (as shown in Figs. 6 and 7) or flat ends (not shown) similar to flat surface 44 of tab 26 shown Fig. 4

[0029] Cap 210 can also have one or more accessible pry slots 246. Slots 246 can be used to assist in removing or prying cap 210 from engagement with mounting tube 12. Slots 246 can be positioned in any accessible area of cap 210. In the illustrated embodiment of Figs. 6-9 slots are positioned about at the intersection of sidewall 234 and central panel 228. It is understood that cap 10 and cap 1 10 can also have accessible slots to assist in removing same.

[0030] In the embodiment illustrated in Figs. 6-9, tabs 226 can be supported by spring arm 240 to allow tabs 226 to clear portions of mounting tube 12 as cap 210 is placed on mounting tube 12 and to return to a position for engaging groove 19. Spring arm 240 and tab 226 can be integrally formed from portions of central panel 228 and sidewall 234, which spaces central panel 228 from lip 230. In the illustrated embodiment, slot 226 and spring arm 238 can be cut or stamped from central panel 228 and sidewall 234 of cap 210. The stamping or cutting of spring arm 234 and slot 226 can create slots 246. Stamping, molding or other methods can be used to form cap 210 from a variety of strong and malleable materials which can resist temperatures of up to about 900° F. such as a metal or metal alloys. In one embodiment, cap 210 is made of aluminum and in another is made of steel. [0031] Central panel 228 can be spaced from lip 230 by sidewall 234 such that when lip 230 engages flange 16 of mounting tube 12 tabs 226 can be in position to engage groove 19. The embodiment illustrated in Figs. 6 and 7 show three tabs 226 and three slots 246 spaced equidistant about sidewall 234.

[0032] Alternatively, tabs 226 with spring arms 240 can be separately attached to cap 210 and slots 226 can be formed independently from tabs 226. In addition, tabs 226 can extend from sidewall 234 or out through sidewall 234. It is understood that more or less tabs 226 can be used.

[0033] While the present disclosure has been described in detail with reference to the foregoing embodiments, other changes and modifications may still be made without departing from the spirit or scope of the present disclosure. It is understood that the present disclosure is not to be limited by the embodiments described herein. Indeed, the true measure of the scope of the present disclosure is defined by the appended claims including the full range of equivalents given to each element of each claim.

Claims

1 . A muffler comprising

a. a mounting tube for mounting said muffler to an internal combustion engine, said mounting tube including a groove at an open end thereof; and

b. a cap for closing off said open end of the mounting tube, said cap comprising a cover and a tab for engaging said groove to retain the cap to said mounting tube.

2. The muffler of claim 1 wherein the cap includes a central panel, a lip raised relative to said central panel and a sidewall connecting said central panel to said lip, said tab extends beyond a radial extent of said sidewall.

3. The muffler of claim 2 wherein said tab is connected to a spring arm for permitting biasing of said tab.

4. The muffler of claim 3 wherein said spring arm extends from said central panel.

5. The muffler of claim 4 wherein said spring arm and tab are cut out from said sidewall and central panel and define a pry slot.

6. The muffler of claim 5 where said cap further includes a body having a sidewall and connected to said cover, the radial extent of said sidewall being less than the radial extent of said cover.

7. The muffler of claim 6 wherein said body includes a neck extending radially outwardly from said sidewall to connect said body with said cover.

8. The muffler of claim 7 wherein said tab extends from said sidewall.

9. The muffler of claim 8 wherein said tab is connected to a spring arm for biasing said tab.

10. The muffler of claim 9 wherein the spring arm and tab are integrally formed from said sidewall.

1 1 . The muffler of claim 10 wherein said cover includes a central panel spaced from an annular lip.

12. The muffler of claim 1 1 wherein said lip is folded over itself to define a groove for engaging said neck to secure said cover to said body.

13. The muffler of claim 1 1 wherein said cover and body are formed from one integral piece of material.

14. The muffler of any one of the preceding claims wherein the cap includes three tabs spaced an equal distance from each about the cap.

15. The muffler of any one of the preceding claims wherein an outer edge the tab has either a flat surface or an arcuate surface.

16. A cap for closing off the open end of a muffler mounting tube having a groove adjacent the open end, the cap comprising: a cover for closing the open end of the mounting tube and at least one tab for engaging the groove to retain the cover to the mounting tube.

17. The cap of claim 16 wherein the cover includes a central panel and a lip raised relative to said central panel, a sidewall connecting said central panel to said lip.

18. The cap of claim 16 or 17 wherein the at least on tab is connected to a spring arm.

19. The cap of claim 18 wherein said spring arm extends from said central panel.

20. The cap of claim 19 wherein said spring arm and at least one tab are cut out of said sidewall and central panel to define a pry slot.

21 . The cap of claim 16 where said cap further includes a body having a sidewall connected to said cover, the radial extent of said sidewall being less than the radial extent of said cover.

22. The cap of claim 21 wherein said body includes a neck extending radially outwardly from said sidewall to connect said body with said cover.

23. The cap of claim 22 wherein said tab extends from said sidewall.

24. The cap of claim 23 wherein said tab is connected to a spring arm for permitting biasing of said tab.

25. The cap of claim 24 wherein the spring arm and tab are integrally formed from the sidewalk

26. The cap of any one of claims 21 -25 wherein said cover includes a central panel and a raised annular lip.

27. The cap of claim 26 wherein said lip is folded over itself to define a groove for engaging said neck to secure said cover to said body.

28. The cap of claim 26 wherein said cover and body are form from one integral piece of material.

29. The cap of any one of claims 27 and 28 wherein the cap includes three tabs spaced an equal distance from each other along said sidewalk

30. The cap of any one of claims 16-29 wherein an outer edge of each of the at least one tab has either a flat surface or an arcuate surface.