초록 ▼

A grader vehicle has a vehicle body mounted on two drive tracks. A boom is mounted on the front of the vehicle and extends to the front of the body. A third drive track is mounted on the leading end of the boom by a steering mechanism for rotation about an upright steering axis. The three tracks are

A grader vehicle has a vehicle body mounted on two drive tracks. A boom is mounted on the front of the vehicle and extends to the front of the body. A third drive track is mounted on the leading end of the boom by a steering mechanism for rotation about an upright steering axis. The three tracks are driven by separate hydraulic motors. The use of a steering, driven track on the boom provides a tractive force pulling the vehicle forwards in the desired direction of travel and positively driving the leading end of the boom in the direction of a turn. The track also provides a degree of packing at the center of the vehicle's path that can not be achieved with a ski gliding on the surface. This is of particular importance when packing ski trails with the vehicle. For grading purposes, the vehicle has a grader blade across the front of the vehicle and a second blade leading the front track. This provides both grading and packing at the center of the track where prior art tracked vehicles would at most provide a grading action with a scraper blade.

대표청구항 ▼

1. A vehicle comprising: a vehicle body; two endless drive track assemblies mounted on opposite sides of the body; an elongate boom mounted on the body and extending in a forwards direction from the body; a third endless drive track assembly; a scraper blade positioned between the third track

1. A vehicle comprising: a vehicle body; two endless drive track assemblies mounted on opposite sides of the body; an elongate boom mounted on the body and extending in a forwards direction from the body; a third endless drive track assembly; a scraper blade positioned between the third track assembly and the vehicle body; a steering mechanism mounting the third endless drive track assembly on the boom, spaced forwardly from the body, for rotation about an upright steering axis; and drive means for driving each of the drive track assemblies. 2. A vehicle according to claim 1 wherein the boom is immovably fixed to the vehicle body and each of the two endless drive track assemblies mounted on the body includes a walking beam suspension. 3. A vehicle according to claim 1 including a leading scraper blade mounted on the boom at a position leading the third track assembly. 4. A vehicle according to claim 3 including means for raising and lowering the leading scraper blade. 5. A vehicle according to claim 4 wherein the leading scraper blade is mounted on the third track assembly for steering movement therewith. 6. A vehicle according to claim 1 including means for raising and lowering the scraper blade. 7. A vehicle according to claim 6 including means for turning the scraper blade about an upright axis relative to the vehicle body. 8. A vehicle according to claim 7 including means for tilting the scraper blade from side to side. 9. A vehicle according to claim 1 wherein the drive means comprise hydraulic motors for the respective tracks.