Wheel substitutes for land vehicles – Endless belt having nonmetallic track or tread – Track formed of endless flexible belt
Reexamination Certificate
2002-05-09
2004-05-11
Stormer, Russell D. (Department: 3617)
Wheel substitutes for land vehicles
Endless belt having nonmetallic track or tread
Track formed of endless flexible belt
Reexamination Certificate
active
06733091
ABSTRACT:
FIELD OF THE INVENTION
This invention relates to an endless track which is made of a reinforced rubber material with tread patterns having a first pitch and with longitudinally spaced and transversely disposed drive lugs, having a second pitch, different from the first pitch.
DESCRIPTION OF RELATED ART
In the snowmobile industry, it has been a standard practice to have the drive lugs located exactly under the tread lug (traction lugs) which are both aligned with a composite stiffener which is used to reinforced the track. See for example U.S. Design Pat. No. 436,892 (Soucy & al). This arrangement of tread lug and composite stiffener give the drive lug enough strength to transmit power to the endless track. This leads to a number of drawbacks. One of them is that the drive lug pitch is driven by the outer tread pitch. Therefore, one has to compromise when designing a track since both elements accomplish different duties. The tread lugs cannot be too close together since the traction in snow would be reduced. After many years of development, the standard pitch in a snowmobile track has been set to the present 2.52 inches. At this pitch, although very functional, the noise and rolling resistance generated by the drive lugs are not optimized.
Environmental issues are a big concern in the snowmobile industry and reducing noise and rolling resistance is highly desirable for the comfort of the driver and of the people who are present near areas of snowmobile travel. The lowering of rolling resistance also lowers fuel consumption with the resulting lowering of combustion emissions.
SUMMARY OF THE INVENTION
One aspect of the present invention is to reduce substantially the noise generated from the endless track at all speeds and reduce rolling resistance (and thus fuel consumption) at low to medium speeds (0-70 mph) by having a drive lug pitch different than the tread pitch. It has been found that using a pitch exactly half the pitch of the tread is the best combination for overall snowmobile performance. Using this pitch length, the number of teeth engaged in the sprocket is doubled which reduces the unit impact force at engagement. On a test bench with that configuration, the noise reduction was between 1 to 5 dBa.
There is provided an endless track for a vehicle, the track having an endless body extending along a longitudinal axis and made of reinforced material, the body having a ground engaging outer side and an internal side, the ground-engaging outer side having a tread pattern over the entire length of the track and having a predetermined tread pitch length, the internal side provided with drive lugs repeated over the entire length of the track and having a predetermined drive pitch length, each drive lug having an engaging face laterally extending at an angle which is greater than 90° or lesser than 90° with respect to said longitudinal axis, wherein the drive pitch length differs from the tread pitch length.
These and other aspects and advantages of the present invention are described in or apparent from the following detailed description of a preferred embodiment mad in conjunction with the appended figures.
REFERENCES:
patent: 2050845 (1936-08-01), Jett
patent: 3118709 (1964-01-01), Case
patent: 3948110 (1976-04-01), Lassanske
patent: 4278302 (1981-07-01), Westimayer et al.
patent: 5709440 (1998-01-01), Lecours
patent: 5713645 (1998-02-01), Thompson et al.
patent: D436892 (2001-01-01), Soucy et al.
patent: 6296329 (2001-10-01), Rodgers et al.
patent: 6402268 (2002-06-01), Lussier
patent: 54-44575 (1982-03-01), None
Deland André
St-Pierre Yves
Brouilette Robert
Kosie Ronald S.
Prince Gaetan
Soucy International Inc.
Stormer Russell D.
LandOfFree
Variable pitch track does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Variable pitch track, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Variable pitch track will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3212439