The present invention relates to a ground engaging track which is driven by a drive sprocket to move a vehicle across the ground. More particularly, the present invention relates to a light weight track for use with an off road vehicle such as, for example, a snowmobile.
Snowmobiles are commonly used for trail riding and utility applications. Trail riding on a snowmobile allows a snowmobile enthusiast to travel through areas which are not accessible by other types of vehicles. For example, snowmobiles can travel very rapidly across frozen lakes during the winter in northern climates. Modern snowmobiles, can cover ground very rapidly and can cover great distances.
Snowmobiles typically include a ground engaging track driven by the snowmobile engine to propel the machine. The track is supported beneath a vehicle chassis by a rear suspension which provides a comfortable ride and helps absorb the shock of the snowmobile crossing uneven terrain.
It is desirable to reduce the overall weight of the snowmobile to increase the range that a snowmobile may cover. The present invention helps reduce the weight of the track used to propel the snowmobile.
In one illustrated embodiment of the present invention, a ground engaging track for use with a vehicle having a drive sprocket comprises a continuous loop body portion having an exterior surface to engage the ground and an interior surface including driven members configured to be engaged by the drive sprocket to rotate the body portion and move the vehicle. The body portion is formed from a polymeric material having a Young's modulus greater than 10,000 psi.
In another illustrated embodiment of the present invention, a ground engaging track for use with a vehicle having a drive sprocket comprises a body portion having an exterior surface to engage the ground and an interior surface having driven members configured to be engaged by the drive sprocket to rotate the body portion and move the vehicle. The body portion is molded from a polymeric material having a Young's modulus greater than 10,000 psi. The track further comprises a plurality of reinforcement members molded into the body portion.
In yet another illustrated embodiment of the present invention, a ground engaging track for use with a vehicle having a drive sprocket comprises a body portion having an interior surface including a plurality of drive lugs. The plurality of drive lugs are longitudinally spaced apart to provide driven members configured to be engaged by the drive sprocket to rotate the body portion and move the vehicle. The body portion and the plurality of drive lugs are integrally formed from a polymeric material having a degree of crystallinity greater than or equal to 50%.
In still another illustrated embodiment of the present invention, a ground engaging track for use with a vehicle having a drive sprocket comprises an endless belt body portion having an interior surface including a plurality of drive lugs formed integrally with the body portion. The plurality of drive lugs are longitudinally spaced apart to provide driven members configured to be engaged by the drive sprocket to rotate the body portion and move the vehicle. The body portion also has an exterior surface including a plurality of tread lugs formed integrally with the body portion and configured to engage the ground. A first set of tread lugs is longitudinally aligned with the drive lugs and a second set of tread lugs being longitudinally aligned with spaces between adjacent drive lugs.
In a further illustrated embodiment of the present invention, a ground engaging track for use with a vehicle having a drive sprocket comprises an endless belt body portion having an exterior surface to engage the ground and an interior surface having driven members configured to be engaged by the drive sprocket to rotate the endless belt body portion and move the vehicle. The body portion has a thickness less than 0.2 inch.
In a still further illustrated embodiment of the present invention, a ground engaging track for use with a vehicle having a drive sprocket comprises a continuous loop body portion having an exterior surface to engage the ground and an interior surface including members configured to be engaged by the drive sprocket to rotate the body portion and move the vehicle. The body portion is formed from a polymeric material having a molecular weight greater than two million Daltons.
Additional features of the invention will become apparent to those skilled in the art upon consideration of the following detailed description of the best mode of carrying out the invention as presently perceived.
The detailed description particularly refers to the accompanying figures in which:
Referring now to the drawings,
The vehicle typically includes an engine (not shown), such as an internal combustion engine, that is operatively connected to the track 10 via a drive axle 11. In a snowmobile embodiment, a continuously variable transmission (not shown) illustratively connects the engine to the drive axle 11 in a conventional manner. Drive sprocket 12 is mounted to the drive axle 11 for common rotational movement about a drive sprocket axis 13.
As illustrated in
The sprocket 12 has a central bore 23 formed in hub 15 through which the drive axle 11 extends. The drive axle 11 is rigidly secured to the sprocket 12 in a conventional manner. The sprocket 12 and the Y-shaped projections 17 defining sprocket teeth 19, 21 are illustratively integrally formed from a strong, light material such as aluminum or plastic. Sprocket 12 may also be formed from other suitable material such as steel or a composite including carbon fibers. In other words, the exact composition of the sprocket 12 may be selected from a wide variety of substances without departing from the scope of the present invention. In addition, the sprocket teeth 19, 21 may be formed separately from the sprocket body and subsequently rigidly fastened (via glue, rivets, welds, bolts, etc.) to the sprocket 12.
Illustratively, drive sprocket 12 includes a central channel 30 defined by spaced apart walls 34. Channel 30 receives centering lugs 28 of track 10 therein as the sprocket 12 rotates as discussed below. The channel 30 may be implemented in other suitable configurations, if desired. Teeth 19, 21 of drive sprocket 12 are formed to include apertures 42 therein. Drive sprocket 12 defines cavities 44 in communication with apertures 42 for removal of snow, dirt and other debris as described in greater detail below.
In one embodiment, body portion 14 is molded or otherwise formed as a continuous loop. In another embodiment, body portion is an endless belt track. For purposes of this application, the term “continuous loop” defines a monolithic structure without connectors, couplers or splices. For purpose of this application, the term “endless belt” may include connectors, couplers or splices. In any event, it should be appreciated that alternative embodiments may be implemented in any other suitable configuration.
As previously mentioned, body portion 14 has exterior surface 16 and interior surface 18. The thickness of the body portion 14 of track 10 (distance between exterior surface 16 and interior surface 18) as illustrated by dimension T is less preferably than about 0.2 inch. Illustratively, the thickness is preferably between about 0.2 inch and about 0.1 inch. As illustrated in
Exterior surface 16 includes a plurality of tread lugs 20 configured to engage the ground. Tread lugs 20 are illustratively integrally formed with body portion 14 of track 10. Therefore, tread lugs 20 are also formed from the same polymeric material as the body portion. As illustrated in
Optionally, tread tips 22 are coupled to tread lugs 20. Tread tips 22 are illustratively formed from a second material which is more elastic than the polymeric material of body portion 14 and tread lugs 20. Illustratively, the elastomeric second material has a Young's modulus less than or equal to 5,000 psi and preferably less than or equal to 2,000 psi. For example, tips 22 may be formed from rubber having a Young's modulus of about 1,500 psi.
Tread tips 22 are either co-molded to tread lugs 20 or fastened to tread lugs 20 by any suitable means, such as adhesive. The optional tread tips 22 provide greater traction on hard or icy surfaces. The optional tread tips 22 also reduce noise when track 10 is operated over hard surfaces compared to an embodiment of the track 10 without the tips 22 on the tread lugs 20.
Interior surface 18 includes integrally formed drive lugs 24 which provide driven members 26 that are configured to engage drive sprocket teeth 19, 21. Centering lugs 28 are located between the drive members 26. Drive lugs 24 and centering lugs 28 are illustratively integrally formed from the same polymeric material as the body portion 14. Drive members 26 are configured to be engaged by drive sprocket teeth 19, 21 as the sprocket 12 rotates to rotate body portion 14 and move the vehicle. Centering lugs 28 are configured to enter the central channel 30 of drive sprocket 12 to maintain position of body portion 14 of track 10 relative to drive sprocket 12.
Optionally, centering tips 29 are coupled to centering lugs 28. Centering tips 29 are illustratively formed from a second material which is more elastic than the polymeric material of body portion 14, drive lugs 24 and centering lugs 28. Illustratively, the elastomeric second material has a Young's modulus less than 5,000 psi and preferably less than 2,000 psi. For example, tips 29 may be formed from rubber having a Young's modulus of about 1,500 psi.
Centering tips 29 are either co-molded to centering lugs 28 or fastened to centering lugs 28 by any suitable means, such as adhesive. The optional centering tips 29 may provide greater traction against drive sprocket 12 and may be quieter than an embodiment of track 10 including centering lugs 28 without the tips.
In another embodiment, a track (not shown) is formed to include drive apertures adjacent drive lugs 24. This track embodiment is driven by a sprocket as illustrated in U.S. Pat. No. 7,051,829 to Wahl which is incorporated herein by reference. In this embodiment, centering lugs 28 are not typically used.
As shown in
A plurality of tread lugs 20 are illustratively disposed along a single lateral axis 40. A plurality of sets of tread lugs 20 are disposed parallel to other sets of tread lugs 20. It should be appreciated that tread lugs 20 may be implemented in other suitable configurations.
Optionally, reinforcement members 38 are illustratively embedded within body portion 14. Reinforcement members 38 are illustratively formed from polymeric material having a Young's modulus greater than about 75,000 psi and preferably greater than about 95,000 psi. For example, reinforcement members 38 are made from aramid fibers or a polyester material.
During operation, snow, dirt and other debris can collect on the interior surface 18 of track 10, on drive members 26, and on drive sprocket 12. Apertures 42 formed in sprocket teeth 19, 21 are in communication with cavities 44 to allow snow, dirt and other debris to move through apertures 42 in the directions of arrows 46 as the sprocket 12 rotates to move the track 10. Movement of the snow, dirt or other debris in the direction of arrows 46 allows for removal of the snow, dirt and other debris from interior surface 18, drive members 26 and drive sprocket 12.
Still referring to
Illustratively, drive sprocket 112 is coupled to drive axle 150. Sprocket includes a plurality of teeth 125 which are configured to engage the drive members 126 as the sprocket 112 rotates. Teeth 125 include lateral members 136 having a ramp surface 138 which is configured to aid in removal of snow, dirt and other debris. During operation, snow, dirt and other debris can deposit on the interior surface 118, on drive members 124, and on drive sprocket 112. Space between lateral member 136 and interior surface 118 and the ramp surface 138 facilitate movement of snow, dirt and debris in the direction of arrow 146 to remove the snow, dirt and other debris from interior surface 118, drive members 124 and drive sprocket 112.
Still referring to
As also shown in
As discussed above, the body portion 14, 114 of the track and well as tread lugs 20, 120, drive lugs 24, 124 and centering lugs 28, 128 are illustratively integrally formed from a polymeric material having a Young's modulus greater than 10,000 psi. In other illustrated embodiments the polymeric material has a Young's modulus greater than or equal to 25,000 psi, greater than or equal to 50,000 psi, or greater than or equal to 75,000 psi. In preferred embodiments, the polymeric material is ultra high molecular weight polyethylene having a Young's modulus greater than about 95,000 psi.
The polymeric material of the body portion 14, 114, tread lugs 20, 120, drive lugs 24, 124 and centering lugs 28, 128 may also be defined in terms of the degree of crystallinity of the polymeric material. Illustratively, the polymeric material has a degree of crystallinity greater than or equal to 50%. In other illustrated embodiments the polymeric material has a degree of crystallinity between about 55% and 85%. In preferred embodiments, the polymeric material has a degree of crystallinity greater than or equal to 85%
The polymeric material of the body portion 14, 114, tread lugs 20, 120, drive lugs 24, 124 and centering lugs 28, 128 may also be defined in terms of the molecular weight of the polymeric material. The polymeric material illustratively has a molecular weight greater than two million Daltons. In other illustrated embodiments the body portion is formed from a polymeric material having a molecular weight greater than three million Daltons, greater than four million Daltons, or greater than five million Daltons. In preferred embodiments, the polymeric material is ultra high molecular weight polyethylene having a having a molecular weight between about three million Daltons and about 5.7 million Daltons.
The properties of the polymeric material discussed herein permit the track to be formed from a thin sheet of the polymeric material. Illustratively, the body portion having a thickness less than 0.2 inch. Preferably, the body portion has a thickness between about 0.2 inch and about 0.1 inch.
It is understood that a track made of the polymeric material described herein is not limited to the specific track configurations illustrated herein. Any other configurations of drive lugs, tread lugs, and centering lugs may be used in accordance with the present invention. As discussed above, any desired sprocket configuration may also be used including multiple drive sprockets as is well known in the art. It is also understood that the track may be formed with or without centering lugs, depending on the track design.
Although the invention has been described in detail with reference to certain illustrated embodiments, variations and modifications exist within the scope and spirit of the present invention as described and defined in the following claims.
This application claims the benefit of U.S. Provisional Application Ser. No. 60/885,165 filed on Jan. 16, 2007, which is expressly incorporated by reference herein. PCT Application Serial No. PCT/US2007/004607, filed on Feb. 21, 2007, is also incorporated by reference herein.
Number | Name | Date | Kind |
---|---|---|---|
3118709 | Case | Jan 1964 | A |
3161443 | Svensson | Dec 1964 | A |
3582154 | Russ | Jun 1971 | A |
3602364 | Maglio et al. | Aug 1971 | A |
3700287 | Persin | Oct 1972 | A |
3722962 | Cooper | Mar 1973 | A |
3781067 | Dodson et al. | Dec 1973 | A |
3900231 | Ohm | Aug 1975 | A |
3911051 | Schouten et al. | Oct 1975 | A |
4303278 | Fehling | Dec 1981 | A |
4390214 | Gunter et al. | Jun 1983 | A |
4490321 | Klinka | Dec 1984 | A |
4714302 | Svensson et al. | Dec 1987 | A |
4758055 | Anderson | Jul 1988 | A |
4915895 | Savage et al. | Apr 1990 | A |
4919876 | Savage et al. | Apr 1990 | A |
RE33324 | Edwards et al. | Sep 1990 | E |
5053179 | Masui et al. | Oct 1991 | A |
5238725 | Effing et al. | Aug 1993 | A |
5453240 | D'Hooren | Sep 1995 | A |
5540489 | Muramatsu et al. | Jul 1996 | A |
5672403 | Hara et al. | Sep 1997 | A |
5709440 | Lecours | Jan 1998 | A |
5961902 | Ishitoya et al. | Oct 1999 | A |
6007166 | Tucker et al. | Dec 1999 | A |
6234264 | Boivin et al. | May 2001 | B1 |
6406655 | Courtemanche | Jun 2002 | B1 |
6482508 | Persson et al. | Nov 2002 | B1 |
6536852 | Katayama et al. | Mar 2003 | B2 |
6769746 | Rodgers et al. | Aug 2004 | B2 |
6800686 | Blanchon | Oct 2004 | B2 |
6974196 | Gagne et al. | Dec 2005 | B2 |
6976742 | Girard et al. | Dec 2005 | B2 |
7051829 | Wahl | May 2006 | B2 |
7090312 | Soucy et al. | Aug 2006 | B2 |
20010008687 | Kollaja et al. | Jul 2001 | A1 |
20030019133 | Hori | Jan 2003 | A1 |
20030034690 | Hori et al. | Feb 2003 | A1 |
20030047996 | Soucy et al. | Mar 2003 | A1 |
20030194935 | Schlomski et al. | Oct 2003 | A1 |
20040145095 | McCollum et al. | Jul 2004 | A1 |
20050103540 | Lavoie | May 2005 | A1 |
20050287891 | Park | Dec 2005 | A1 |
20060103236 | Soucy et al. | May 2006 | A1 |
20060125318 | Soucy et al. | Jun 2006 | A1 |
20060175108 | Kubota | Aug 2006 | A1 |
20070046100 | McGilvrey et al. | Mar 2007 | A1 |
20090224598 | St-Amant et al. | Sep 2009 | A1 |
Number | Date | Country |
---|---|---|
0934867 | Aug 1999 | EP |
1 291 270 | Jun 2005 | EP |
1 564 118 | Aug 2005 | EP |
2 077 203 | Dec 1981 | GB |
06072362 | Mar 1994 | JP |
Number | Date | Country | |
---|---|---|---|
20080174176 A1 | Jul 2008 | US |
Number | Date | Country | |
---|---|---|---|
60885165 | Jan 2007 | US |