Monorail vehicle apparatus with gravity-augmented contact load
Apparatus and method for gravity-augmented preload of drive wheels in a monorail vehicle travelling along a guide rail with bearing and contact surfaces that are non-parallel with the gravity vector. The vehicle defines a pivot location against the bearing surface and a constraint point on the contact surface for engaging the rail on the bearing and contact surfaces, respectively. The vehicle is mounted so its center of gravity is at a rear longitudinal offset r rl from the pivot location and a vertical offset r vert from the guide rail. A force and moment balance thus created result in a normal load on a drive wheel engaged with the bearing surface at the pivot location, where the load value exceeds a standard normal load generated by the mass of the monorail vehicle alone.
1. A monorail vehicle apparatus with a gravity-augmented normal load, said apparatus comprising:
a) a rail having a bearing surface and a contact surface that are non-parallel to the gravity vector;
b) a monorail vehicle for traveling on said rail, said monorail vehicle having:
1) a pivot location against said bearing surface;
2) a constraint point against said contact surface;
wherein said monorail vehicle is mounted on said rail such that a center of gravity of said monorail vehicle has a rear longitudinal offset r rl from said pivot location to produce a moment N ap about said pivot location thereby generating said gravity-augmented normal load at said pivot location and at said constraint point beyond a standard normal load of at most the weight of said monorail vehicle.
2. The monorail vehicle apparatus of claim 1 , wherein said monorail vehicle has a drive wheel for propelling said monorail vehicle along said bearing surface of said rail.
3. The monorail vehicle apparatus of claim 1 , wherein said monorail vehicle has a drive wheel for propelling said monorail vehicle along said contact surface.
4. The monorail vehicle apparatus of claim 1 , wherein said rail extends along a rail centerline and said constraint point has a front longitudinal offset r fl from said pivot location.
5. The monorail vehicle apparatus of claim 1 , wherein said rail extends along a rail centerline and said center of gravity has a lateral offset r lat from said rail centerline.
6. The monorail vehicle apparatus of claim 1 , wherein said rail extends along a rail centerline and said center of gravity has a vertical offset r vert below said rail centerline.
7. The monorail vehicle apparatus of claim 1 , wherein said center of gravity has a vertical offset r vert positioned to generate additional normal load when said monorail vehicle is accelerating or braking.
8. The monorail vehicle apparatus of claim 1 , wherein said rail is non-featured and has a predetermined cross-section extending along a rail centerline.
9. The monorail vehicle apparatus of claim 1 , wherein said bearing surface and said contact surface are geometrically opposite each other.
10. The monorail vehicle apparatus of claim 1 , wherein said rail further comprises an alignment datum for locating said monorail vehicle at a predetermined docking location.
11. A method for augmenting normal load by the placement of a center of gravity in a monorail vehicle traveling along a rail having a bearing surface and a contact surface, said method comprising the steps of:
a) mounting said monorail vehicle on said rail such that a pivot location is defined against said bearing surface and a constraint point is defined against said contact surface;
b) placing said center of gravity of said monorail vehicle at a rear longitudinal offset r rl from said pivot location;
whereby said rear longitudinal offset r rl produces a moment N ap about said pivot location thereby augmenting normal load at said pivot location and at said constraint point beyond a standard normal load generated by the mass of said monorail vehicle.
12. The method of claim 11 , further comprising:
a) providing said monorail vehicle with at least one wheel for engaging said bearing surface of said rail at said pivot location; and
b) providing said monorail vehicle with at least one wheel for engaging said contact surface of said rail at said constraint point.
13. The method of claim 12 , wherein said at least one wheel for engaging said bearing surface of said rail is chosen to be a drive wheel for propelling said monorail vehicle along said rail.
14. The method of claim 12 , wherein said at least one wheel for engaging said contact surface is chosen to be a drive wheel for propelling said monorail vehicle along said rail.
15. The method of claim 12 , wherein said at least one wheel for engaging said bearing surface is chosen to be an idler wheel.
16. The method of claim 12 , wherein said at least one wheel for engaging said contact surface is chosen to be an idler wheel.
17. The method of claim 11 , wherein said rail extends along a rail centerline and said constraint point has a front longitudinal offset r fl from said pivot location.
18. The method of claim 11 , wherein said rail extends along a rail centerline and said center of gravity is placed at a lateral offset r lat from said rail centerline.
19. The method of claim 11 , wherein said rail extends along a rail centerline and said center of gravity is placed at a vertical offset r vert below said rail centerline.
20. The method of claim 11 , wherein said center of gravity is positioned at a vertical offset r vert to generate additional normal load when said monorail vehicle is accelerating or braking.
21. The method of claim 11 , wherein said bearing surface and said contact surface are selected to be geometrically opposite surfaces of said rail.
22. The method of claim 11 , wherein said rail is chosen to be non-featured and exhibits a predetermined cross-section extending along a rail centerline.
23. The method of claim 11 , wherein said rail is chosen to be a low-grade stock rail that exhibits substantial profile variation.
24. The method of claim 11 , further comprising providing an alignment datum for locating said monorail vehicle at a predetermined docking location.