Wheel
The wheel is all-metal, and is suitable for use on the moon. The wheel includes tread-plates mounted on leaf-springs, which deflect to permit suspension movement. The leaf-springs are flexible, light, and thin, yet are made strong enough to cope with heavy traction forces by the provision of hoop-cables, which link all the tread-plates together.
1. Wheel, wherein:
the wheel includes a rim, which is fast to a hub of the wheel, for rolling motion about a wheel axis;
the wheel includes many tread-plates;
the wheel includes resiliently flexible tread-springs;
proximal ends of the tread-springs are fast to the rim;
distal ends of the tread-springs are fast to the tread-plates, whereby the tread-plates and tread-springs form tread-units;
the tread-units are so configured that:
(a) the tread-plates are urged radially outwards, with respect to the axis of the wheel, by the resilience of the tread-springs; and
(b) the tread-plates can move, individually, radially inwards against the resilience of the tread-springs;
the tread-units are arranged in a hoop-set, or in hoop-sets;
in respect of the or each hoop-set of tread-plates:
(a) the hoop-set is so configured that each tread-plate of the hoop-set lies circumferentially between adjacent tread-plates of the hoop-set;
(b) the hoop-set includes a hoop-cable;
(c) each one of the tread-plates that make up the hoop-set is fast to the hoop-cable;
(d) the hoop-cable is of so dimensioned that, the wheel being unloaded and the tread-plates being urged radially outwards by the tread-springs, the hoop-cable is under hoop-tension; and
(e) the tread-plates are each fastened to the hoop-cable in such manner that, the wheel being unloaded, adjacent tread-plates can approach but cannot separate, circumferentially.
2. A wheel as claimed in claim 1 wherein the wheel is metal.
3. A wheel as claimed in claim 1 wherein the wheel is all metal.
4. A wheel as claimed in claim 1 , wherein:
the tread-plates are independent;
the resiliently flexible tread-springs are independent leaf springs;
distal ends of the tread-springs are fast to the tread-plates, whereby the tread-plates and tread-springs form independent tread-units;
the tread-springs are so configured that:
(a) the tread-plates are urged radially outwards, with respect to the axis of the wheel, by the resilience of the tread-springs; and
(b) the tread-plates can move, individually, radially inwards against the resilience of the tread-springs;
(c) the tread-units are restrained, individually, by respective tread springs against movement parallel to the wheel axis;
the hoop cable is inelastic and flexible.
5. A wheel as claimed in claim 4 wherein the wheel is metal.
6. A wheel as claimed in claim 4 wherein the wheel is all metal.
7. An all metal wheel as claimed in claim 6 , wherein the tread units are held firmly, individually, by respective tread-springs in position axially relative to the wheel.
8. An all metal wheel as claimed in claim 7 , wherein the wheel is so structured that, when the wheel is in an operational loaded condition, and the wheel is rolling over the ground:
the tread-plate of a bottom one of the tread-units makes direct touching contact with the ground;
the tread-spring of the bottom tread-unit deflects radially inwards relative to the axis of the wheel;
in the other tread-units that are clear of the ground, the tread-springs urge the tread-plates radially outwards, against the tension of the hoop cable.
9. An all metal wheel as claimed in claim 8 , wherein:
each tread-unit comprises one tread-plate and just one tread-spring that is fast to the rim and to the tread-plate; and
the wheel includes left and right hoop-sets of tread-units, having respective hoop-cables.
10. An all metal wheel as claimed in claim 9 , wherein:
in the tread-units of the left hoop-set:
(a) the left tread-plates lie to the left of the rim;
(b) the proximal ends of the left tread-springs are fast to the right side of the rim;
(c) the left tread-springs extend over the rim, and their distal ends are fast to the left tread-plates;
in the tread-units of the right hoop-set:
(a) the right tread-plates lie to the right of the rim;
(b) the proximal ends of the right tread-springs are fast to the right side of the rim;
(c) the right tread-springs extend over the rim, and their distal ends are fast to the right tread-plates.
11. An all metal wheel as claimed in claim 8 , wherein:
the wheel includes just one hoop-set of tread-units;
each tread-unit comprises left and right tread-springs and just one tread-plate;
the left and right tread-springs are fast to the rim and to the tread-plate;
left and right hoop-cables are fast to left and right ends of the tread-plates.
12. An all metal wheel as claimed in claim 11 , wherein:
the tread-plates span across the width of the wheel, over the rim;
the proximal ends of the left tread-springs are fast to the left side of the rim;
the distal ends of the left tread-springs are fast to the left end of the tread-plate;
the proximal ends of the right tread-springs are fast to the right side of the rim;
the distal ends of the right tread-springs are fast to the right end of the tread-plate.
13. An all metal wheel as claimed in claim 8 , wherein:
the wheel includes rim-brackets, which are fast to the rim;
each rim-bracket is formed with a rim-bracket surface, to which the proximal ends of the tread-springs are fast.
14. An all metal wheel as claimed in claim 8 , wherein, in respect of each tread-unit, the or each tread-spring is a leaf-spring, being of sheet metal.
15. An all metal wheel as claimed in claim 14 , wherein the wheel is so configured that:
the thickness-dimension of the leaf-spring lies predominantly radially with respect to the wheel;
the width-dimension of the leaf-spring lies in a plane that is predominantly tangential with respect to the wheel; and
the length-dimension lies predominantly parallel to the wheel-axis of the wheel.
16. An all metal wheel as claimed in claim 14 , wherein:
the leaf-spring has a flex-length comprising the length of that portion of the tread-spring that, in operation, is capable of undergoing resilient deflection; and
the flex-length is half of the overall width of the wheel, or more.
17. An all metal wheel as claimed in claim 16 , wherein, at every point on the flex-length of the leaf-spring, a tangent to the leaf-spring at that point lies at an angle that is within thirty degrees of being parallel to the wheel-axis of the wheel.
18. An all metal wheel as claimed in claim 16 , wherein:
each point on the flex-length of each leaf-spring has a tread-spring radius, being a radial line joining the wheel-axis to that point of the tread-spring;
the tread-unit is so mounted with respect to the rim that the plane of the sheet metal of the tread-spring at the point lies within thirty degrees of being perpendicular to the tread-spring radius at the point.
19. An all metal wheel as claimed in claim 14 , wherein:
a wheel-radius of a point in the wheel is a line that is perpendicular to the wheel-axis, and extends from the wheel-axis to the point;
the wheel-radius of the proximal end of the leaf-spring is shorter than the wheel-radius of the distal end.
20. An all metal wheel as claimed in claim 8 , wherein the hoop-cables are of such hoop-length that the actually-enabled-deflection of the tread-spring is between thirty percent and seventy percent of the overall deflection-capability of the tread-spring.
21. An all metal wheel as claimed in claim 8 , wherein:
in respect of each tread-unit the or each tread-plate has no physical attachment to the rim except through the respective tread-springs; and
the hoop-cables have no direct physical connection to the rim.
22. An all metal wheel as claimed in claim 8 , wherein the rim is part of a unitary integrated hub-spokes-rim component of the wheel.
23. An all metal wheel as claimed in claim 8 , wherein all components of the wheel are of metal and
the tread-plates are of titanium;
the tread-springs are of spring-steel.