SNOW BIKE CONVERSION SYSTEM

• US 20120222908A1
• Filed: 03/01/2011
• Published: 09/06/2012
• Est. Priority Date: 03/01/2011
• Status: Active Grant

• Current Assignee: Polaris Industries Incorporated (Polaris Inc.)
• Original Assignee: Polaris Industries Incorporated (Polaris Inc.)
• Inventors: Mangum, Allen
• Granted Patent: US 8,910,738 B2
• Time in Patent Office: Days
• US Class Current: 180/193
• CPC Class Codes: B62D 55/04 with tracks and alternative ground wheels, e.g. changeable from endless track vehicle into wheeled vehicle and vice versa for multi-purpose tractors B62D49/0635
• CPC Class Codes: B62D 55/07 Mono-track vehicles
• CPC Class Codes: B62D 55/112 with fluid springs, e.g. hydraulic pneumatic
• CPC Class Codes: B62M 2027/022 Snow drive conversions for cycles with wheels
• CPC Class Codes: B62M 27/02 power driven

Abstract

A snow bike system includes a motorcycle converted for use in the snow with a rear suspension and belt track system. The belt track is relatively very wide and driven by a front wheel sprocket through a jackshaft. Matching shocks and struts in the rear suspension independently equalize the pressure applied to the ground. The rear strut is a sliding extension type that causes the front of the sliders to kick up when fully compressed during acceleration or climbing uphill. Increased weight on the rear track is shifted forward to keep the front ski down. The jackshaft provides both disc braking and moves the motorcycle engine drive power outboard to accommodate the wider belt track. A tubular subframe and tunnel rigidly mounts to the motorcycle'"'"'s original rear swing arm pivots and shock mounts.

Claims

1. A snow bike system, comprising:

a motorcycle with an engine, and which has had its front wheel and its rear wheel and swing arm suspension removed;

a single steering ski assembly installed in the place of the front wheel; and

a rear track drive assembly installed in the place of the rear wheel and swing arm suspension, and having a track slide and track belt connected to be driven by said engine on the motorcycle, and a forward belt roller, a rear belt roller is suspended with and positioned aft of the track slide;

characterized by;

a rigid mounting of the rear track drive assembly to the motorcycle, and including a tubular frame disposed in the rear track drive assembly and providing for a solid strut connection and a swing arm pivot connection to the motorcycle;

a track tunnel rigidly attached to the underside of the tubular frame and having opposite side skirts providing rigid mounts for the jackshaft, forward belt roller, gas shocks, and struts;

a jackshaft in a sealed case mounted to the track tunnel and providing for the transmission of power from the engine to the track belt through the forward belt roller; and

a suspension system in which the track belt collapses flat and the separation distance increases between the forward and rear belt rollers as trail impacts and weight load changes are absorbed, and configured such that the front of the track slide is forcefully cantilevered up relative to the rear belt roller at particular points of the track belt collapse.

2. The snow bike system of claim 1, further comprising:

a front gas shock and front strut disposed in the front half of the suspension system and track drive assembly for controlling the response of the front portion of the track slide to loads and acceleration;

a rear gas shock and rear strut disposed in the aft half of the suspension system and track drive assembly for controlling the response of the rear belt roller and back portion of the track slide to loads and acceleration.

3. The snow bike system of claim 2, further comprising:

an extension slide included in the rear strut that permits the length of the rear strut to slip between minimum and maximum limits of extension, and connected within the suspension system such that when it is forced to its minimum length of extension the front portion of the track slide is kicked and cantilevered up relative to the rear belt roller and back portion of the track slide to increase the angle of attack.

4. The snow bike system of claim 2, further comprising:

an extension slide included in the rear strut that permits the length of the rear strut to slip between adjustable minimum and maximum limits of extension, wherein the adjustments include the use of removable shims.

5. A conversion system for converting a motorcycle, with an engine but with its front wheel and its rear wheel and swing arm suspension removed, into a snow bike, the conversion system comprising:

a single steering ski assembly configured to fit in the place of the front wheel;

a rear track drive assembly configured to fit in the place of the rear wheel and swing arm suspension, and having a track slide and track belt connected to be driven by said engine on the motorcycle, and a forward belt roller, a rear belt roller is suspended with and positioned aft of the track slide;

a rigid mounting of the rear track drive assembly to the motorcycle, and including a tubular frame disposed in the rear track drive assembly and providing for a solid strut connection and a swing arm pivot connection to the motorcycle;

a track tunnel rigidly attached to the underside of the tubular frame and having opposite side skirts providing rigid mounts for the jackshaft, forward belt roller, gas shocks, and struts;

a jackshaft in a sealed case mounted to the track tunnel and providing for the transmission of power from the engine to the track belt through the forward belt roller; and

a suspension system in which the track belt collapses flat and the separation distance increases between the forward and rear belt rollers as trail impacts and weight load changes are absorbed, and configured such that the front of the track slide is forcefully cantilevered up relative to the rear belt roller at particular points of the track belt collapse.

6. The conversion system of claim 5, further comprising:

a front gas shock and front strut disposed in the front half of the suspension system and track drive assembly for controlling the response of the front portion of the track slide to loads and acceleration;

a rear gas shock and rear strut disposed in the aft half of the suspension system and track drive assembly for controlling the response of the rear belt roller and back portion of the track slide to loads and acceleration.

7. The conversion system of claim 6, further comprising:

an extension slide included in the rear strut that permits the length of the rear strut to slip between minimum and maximum limits of extension, and connected within the suspension system such that when it is forced to its minimum length of extension the front portion of the track slide is kicked and cantilevered up relative to the rear belt roller and back portion of the track slide to increase the angle of attack.

8. The snow bike system of claim 6, further comprising:

an extension slide included in the rear strut that permits the length of the rear strut to slip between adjustable minimum and maximum limits of extension, wherein the adjustments include the use of removable shims.

9. A snow bike suspension system extension slide included in a rear strut assembly associated with a rear shock that permits the length of the rear strut to slip between minimum and maximum limits of extension, and for connection within a suspension system such that when the rear strut assembly is forced to its minimum length of extension the front portion of a track slide is kicked and cantilevered up relative to a rear belt roller and back portion of the track slide to increase its angle of attack.

10. The snow bike suspension system extension slide of claim 9, wherein the extension slide permits the length of the rear strut to slip between adjustable minimum and maximum limits of extension, and any adjustments include the use of removable shims.