Carving toboggan

Abstract

There is disclosed a vehicle ( 1 ) for travelling over snow or the like and comprising a straight runner means ( 19 ) and one or more curved runners ( 21, 23, 25 ) convex towards the straight runner means. When the vehicle is level it travels on the straight runner means in a straight line. By rolling the vehicle to one side, one of the curved runners engages the snow and the vehicle performs a carving turn whose radius is determined by the radius of the runner. Different turn radii are selectable by altering the roll angle of the vehicle. Embodiments are described for use on snow and ice and a wheeled version for use on hard surfaces is also disclosed.

1 . A hull ( 1 ,  9 ,  111 ) for sliding over a carveable medium ( 5 ), and having a longitudinal axis ( 15 ) about which the hull can roll relative to the medium, the hull comprising: 
 straight runner means ( 19 ) for travelling on the medium in a substantially straight line ( 90   a ) when the hull is at a first roll angle relative to the medium; and    a longitudinally extending curved runner ( 21 ,  31 ,  43 ;  23 ,  33 ,  45 ;  25 ,  35 ,  47 ) convex towards the straight runner means and arranged to contact the medium when the hull is at a second roll angle (b, c, d) relative to the medium;    characterised in that the curved runner comprises a substantially circularly arcuate portion ( 21 ,  23 ,  25 ) of a first radius (r1, r2, r3) for travelling on the medium in a substantially circular path ( 90   b ,  90   c ,  90   d ) by carving the medium when the hull is at the second roll angle, and    in that relative to the longitudinal axis, the straight runner means and the curved runner comprise a portion towards the middle (FIG. 7) and two end portions (FIG. 6), and wherein the straight runner means and the curved runner are arranged in a first arc ( 51 X), when viewed at an end portion in a plane (XX′) transverse to the longitudinal axis, and in a second arc ( 51 Y), when viewed at the middle portion in a plane (YY′) transverse to the longitudinal axis, and wherein the first arc is more tightly curved than the second arc.    
     
     
         2 . A hull according to  claim 1 , wherein the straight runner means ( 19 ) comprises a straight surface ( 19 ).  
     
     
         3 . A hull according to  claim 1 , wherein the straight runner means ( 19 ) comprises a pair of oppositely curved runners convex towards each other.  
     
     
         4 . A hull according to any of  claims 1  to  3 , wherein the curved runner is a first curved runner, the hull further comprising a second longitudinally extending curved runner arranged on the side of the straight runner means ( 19 ) opposite to the first curved runner and convex toward the straight runner means, wherein the second curved runner comprises a substantially circularly arcuate portion ( 21 ,  23 ,  25 ) of a second radius (r1, r2, r3) for travelling on the medium ( 5 ) in a substantially circular path ( 90   b ,  90   c ,  90   d ) by carving the medium ( 5 ) when the vehicle is at a third roll angle (b, c, d) relative to the medium.  
     
     
         5 . A hull according to  claim 4 , wherein the first and second radii are equal.  
     
     
         6 . A hull according to  claim 5 , wherein the first and second curved runners are symmetrically arranged with respect to the straight runner means ( 19 ).  
     
     
         7 . A hull according to  claim 4 ,  5  or  6 , comprising a plurality of longitudinally extending curved runners arranged on one side of the straight runner means ( 19 ), each curved runner being convex toward the straight runner means and comprising a respective substantially circularly arcuate portion ( 21 ,  23 ,  25 ) of a respective radius (r1, r2, r3) for travelling on the medium ( 5 ) in a substantially circular path of that radius ( 90   b ,  90   c ,  90   d ) by carving the medium when the vehicle is at a respective roll angle (b, c, d) relative to the medium.  
     
     
         8 . A hull according to  claim 7 , wherein the respective roll angle (b, c, d) of a curved runner nearer the straight runner means ( 19 ) is less than the roll angle of a curved runner spaced further from the straight runner means.  
     
     
         9 . A hull according to  claim 4 ,  5  or  6 , comprising a plurality of longitudinally extending curved runners arranged on each side of the straight runner means ( 19 ), each curved runner being convex toward the straight runner means and comprising a respective substantially circularly arcuate portion ( 21 ,  23 ,  25 ) of a respective radius (r1, r2, r3) for travelling on the medium ( 5 ) in a substantially circular path of that radius ( 90   b ,  90   c ,  90   d ) by carving the medium when the vehicle is at a respective roll angle (b, c, d) relative to the medium.  
     
     
         10 . A hull according to  claim 9 , wherein the curved runners are symmetrically arranged with respect to the straight runner means ( 19 ).  
     
     
         11 . A hull according to any one of claims  4 ,  5 ,  7  to  10 , wherein each of the circularly arcuate portions ( 21 ,  23 ,  25 ) has a tilt-radius product defined by the tangent of the roll angle (b, c, d) associated with the circularly arcuate portion multiplied by the radius (r1, r2, r3) associated with the circularly arcuate portion, and wherein the tilt-radius products of the circularly arcuate portions are substantially equal.  
     
     
         12 . A hull according to any one of claims  4 ,  5 ,  7  to  10 , wherein each of the circularly arcuate portions ( 21 ,  23 ,  25 ) has a tilt-radius product defined by the tangent of the roll angle (b, c, d) associated with the circularly arcuate portion multiplied by the radius (r1, r2, r3) associated with the circularly arcuate portion, and wherein for any two circularly arcuate portions having different associated roll angles, the tilt-radius product of the circularly arcuate portion having the smaller associated roll angle is larger than the tilt-radius product of the circularly arcuate portion having the larger associated roll angle.  
     
     
         13 . A hull according to  claim 12  when dependent on any one of  claims 7  to  10 , comprising three circularly arcuate portions ( 21 ,  23 ,  25 ) arranged on a side of the straight runner means ( 19 ), wherein the tilt-radius products of the three circularly arcuate portions are substantially in the ratio 9:6:3.  
     
     
         14 . A hull according to  claim 13 , wherein the tilt-radius products of the three circularly arcuate portions ( 21 ,  23 ,  25 ) are substantially 0.9, 0.6 and 0.4 when their associated radii (r1, r2, r3) are measured in metres.  
     
     
         15 . A hull according to any preceding claim, wherein the curved runner or runners comprise first and second circularly arcuate portions having different centres of curvature.  
     
     
         16 . A hull according to any preceding claim, wherein, relative to the longitudinal axis ( 15 ), the straight runner means ( 19 ) and the one or more curved runners comprise a portion towards the middle (FIG. 7) and two end portions (FIG. 6), and wherein the straight runner means and the one or more curved runners are arranged in a substantially circular arc ( 51 X) when viewed at an end portion in a plane (XX′) transverse to the longitudinal axis.  
     
     
         17 . A hull according to any preceding claim, wherein the circularly arcuate portion of the curved runner or runners comprises a cylindrical carving face ( 21 ,  23 ,  25 ).  
     
     
         18 . A hull according to  claim 17 , wherein the circularly arcuate portion of the curved runner or runners comprises a circularly arcuate running face ( 31 ,  33 ,  35 ) which meets the carving face ( 21 ,  23 ,  25 ) at an edge.  
     
     
         19 . A hull according to  claim 18 , wherein the running face meets the carving face at an angle of from 75° to 105°.  
     
     
         20 . A hull according to  claim 19 , wherein the running face meets the carving face at an angle of 90°.  
     
     
         21 . A vehicle comprising a hull according to any preceding claim and a deck ( 11 ), wherein the deck is mounted on the hull and the hull is integrally formed with the straight runner means ( 19 ) and the one or more curved runners.  
     
     
         22 . A vehicle according to  claim 21 , wherein the hull ( 9 ) comprises a substantially cylindrical central portion and a pair of upwardly inclined tapered ends ( 27 ).  
     
     
         23 . A vehicle according to  claim 22 , wherein the tapered ends ( 27 ) are upwardly inclined at an angle (α) in the range 30° to 45°.  
     
     
         24 . A vehicle according to  claim 23 , wherein the tapered ends ( 27 ) are upwardly inclined at an angle (α) of 38°.  
     
     
         25 . A vehicle according to any preceding claim, wherein at least a portion of the straight runner means ( 19 ) or the one or more curved runners is replaceable.  
     
     
         26 . A vehicle according to any preceding claim, further comprising an attachment point ( 2 ) for a leash ( 4 ).  
     
     
         27 . A hull ( 9 ) for a vehicle according to any one of  claims 21  to  26 .  
     
     
         28 . A hull according to  claim 27 , wherein the hull is formed from a moulded plastics material.  
     
     
         29 . A hull according to  claim 27  or  28 , for fixing to a deck ( 11 ), the hull comprising two mounting regions ( 113 ,  114 ) for attaching the hull to the deck by means of fasteners ( 14 ) passing through the deck.  
     
     
         30 . A hull according to  claim 29 , wherein one of the mounting regions comprises a plurality of mounting holes ( 113 ) and the other mounting region comprises a pair of slots ( 114 ) extending longitudinally of the hull.  
     
     
         31 . A hull according to  claim 27  or  claim 28 , further comprising attachment means for attaching the hull to a skateboard.  
     
     
         32 . A hull according to  claim 31 , wherein the hull is attachable to a skateboard by engaging the skateboard wheels.  
     
     
         33 . A hull according to  claim 31 , wherein the hull is attachable to a skateboard by engaging the skateboard axles.  
     
     
         34 . A vehicle ( 1 ;  9 ;  111 ;  129 ;  130 ) for sliding over a carveable medium ( 5 ) and having a longitudinal axis ( 15 ) about which the vehicle can roll relative to the medium, the vehicle comprising: 
 straight runner means ( 19 ) for travelling on the medium in a substantially straight line ( 90   a ) when the vehicle is at a first roll angle relative to the medium; and    a longitudinally extending curved runner ( 21 ,  31 ,  43 ;  23 ,  33 ,  45 ;  25 ,  35 ,  47 ) convex towards the straight runner means and arranged to contact the medium when the vehicle is at a second roll angle (b, c, d) relative to the medium;    characterised in that the curved runner is substantially part of a surface of revolution of a first radius (r1, r2, r3) about an axis that i) lies in a plane perpendicular to the said longitudinal axis, ii) is positioned towards the middle of the vehicle and iii) is inclined so that the curved runner can carve a substantially circular path ( 90   c ,  90   c ,  90   d ) in the medium when the vehicle is at the second roll angle.    
     
     
         35 . A vehicle according to  claim 34 , wherein the straight runner means ( 19 ) comprises a straight surface ( 19 ).  
     
     
         36 . A vehicle according to  claim 34 , wherein the straight runner means ( 19 ) comprises a pair of oppositely curved runners convex towards each other.  
     
     
         37 . A vehicle according to any one of  claims 34  to  36 , wherein the curved runner is a first curved runner and further comprising a second longitudinally extending curved runner arranged on the side of the straight runner means ( 19 ) opposite to the first curved runner and convex toward the straight runner means and arranged to contact the medium ( 5 ) when the vehicle is at a third roll angle (b, c, d,) relative to the medium, and wherein the second curved runner is substantially part of a surface of revolution of a second radius (r1, r2, r3) about an axis that i) lies in a plane perpendicular to the longitudinal axis, ii) is positioned towards the middle of the vehicle and iii) is inclined so that the curved runner can carve-a substantially circular path ( 90   b ,  90   c ,  90   d ) in the medium when the vehicle is at the third roll angle.  
     
     
         38 . A vehicle according to  claim 37 , wherein the first and second radii are equal.  
     
     
         39 . A vehicle according to  claim 38 , wherein the first and second curved runners are symmetrically arranged with respect to the straight runner means ( 19 ).  
     
     
         40 . A vehicle according to  claim 37 ,  38  or  39 , comprising a plurality of longitudinally extending curved runners arranged on one side of the straight runner means ( 19 ), each curved runner being convex toward the straight runner means and arranged to contact the medium ( 5 ) when the vehicle is at a respective roll angle (b, c, d) relative to the medium, wherein each curved runner is substantially part of a respective surface of revolution of a respective radius (r1, r2, r3) about a respective axis that i) lies in a plane perpendicular to the longitudinal axis, ii) is positioned towards the middle of the vehicle and iii) is inclined so that each curved runner can carve a respective substantially circular path ( 90   b ,  90   c ,  90   d ) in the medium when the vehicle is at the respective roll angle.  
     
     
         41 . A vehicle according to  claim 40 , wherein the respective roll angle (b, c, d) of a curved runner nearer the straight runner means ( 19 ) is less than the roll angle of a curved runner spaced further from the straight runner means.  
     
     
         42 . A vehicle according to  claim 37 ,  38  or  39 , comprising  1   a  plurality of longitudinally extending curved runners arranged on each side of the straight runner means ( 19 ), each curved runner being convex toward the straight runner means and arranged to contact the medium ( 5 ) when the vehicle is at a respective roll angle (b, c, d) relative to the medium, wherein each curved runner is substantially part of a respective surface of revolution of a respective radius (r1, r2, r3) about a respective axis that lies i) in a plane perpendicular to the longitudinal axis ( 15 ), ii) is positioned towards the middle of the vehicle and iii) is inclined so that each curved runner can carve a respective substantially circular path ( 90   b ,  90   c ,  90   d ) in the medium when the vehicle is at the respective roll angle.  
     
     
         43 . A vehicle according to  claim 42 , wherein the curved runners are symmetrically arranged with respect to the straight runner means ( 19 ).  
     
     
         44 . A vehicle according to any one of claims  37 ,  38 ,  40  to  43 , wherein each of the curved runners has a tilt-radius product defined by the tangent of the roll angle (b, c, d) associated with the curved runner multiplied by the radius (r1, r2, r3) associated with the curved runner, and wherein the tilt-radius products of the curved runners are substantially equal.  
     
     
         45 . A vehicle according to any one of claims  37 ,  38 ,  40  to  43 , wherein each of the curved runners has a tilt-radius product defined by the tangent of the roll angle (b, c, d) associated with the curved runner multiplied by the radius (r1, r2, r3) associated with the curved runner, and wherein for any two curved runners having different associated roll angles, the tilt-radius product of the curved runner having the smaller associated roll angle is larger than the tilt-radius product of the curved runner having the larger associated roll angle.  
     
     
         46 . A vehicle according to  claim 45  when dependent on any one of  claims 40  to  43 , comprising three curved runners arranged on a side of the straight runner means ( 19 ), wherein the tilt-radius products of the three curved runners are substantially in the ratio 9:6:3.  
     
     
         47 . A vehicle according to  claim 46 , wherein the tilt-radius products of the three curved runners are substantially 0.9, 0.6 and 0.4 when their associated radii (r1, r2, r3) are measured in metres.  
     
     
         48 . A vehicle according to any one of  claims 34  to  47 , wherein the curved runner or runners comprise first and second surfaces of revolution, about different axes.  
     
     
         49 . A hull according to any one of  claims 34  to  48 , wherein, relative to the longitudinal axis ( 15 ), the straight runner means ( 19 ) and the one or more curved runner comprise a portion towards the middle (FIG. 7) and two end portions (FIG. 6), and wherein the straight runner means and the one or more curved runners are arranged in a first arc ( 51 X), when viewed at an end portion in a plane (XX′) transverse to the longitudinal axis, and in a second arc ( 51 Y), when viewed at the middle portion in a plane (YY′) transverse to the longitudinal axis, and wherein the first arc is more tightly curved than the second arc.  
     
     
         50 . A vehicle according to any one of  claims 34  to  49 , wherein, relative to the longitudinal axis ( 15 ), the straight runner means ( 19 ) and the one or more curved runners comprise a portion towards the middle (FIG. 7) and two end portions (FIG. 6), and wherein the straight runner means and the one or more curved runners are arranged in a substantially circular arc ( 51 X) when viewed at an end portion in a plane (XX′) transverse to the longitudinal axis.  
     
     
         51 . A vehicle according to any one of  claims 34  to  50 , wherein the circularly arcuate portion of the curved runner or runners comprises a cylindrical carving face ( 21 ,  23 ,  25 ).  
     
     
         52 . A vehicle according to  claim 51 , wherein the circularly arcuate portion of the curved runner or runners comprises a circularly arcuate running face ( 31 ,  33 ,  35 ) which meets the carving face ( 21 ,  23 ,  25 ) at an edge.  
     
     
         53 . A vehicle according to  claim 52 , wherein the running face meets the carving face at an angle of from 75° to 105°.  
     
     
         54 . A vehicle according to  claim 53 , wherein the running face meets the carving face at an angle of 90°.  
     
     
         55 . A vehicle according to any one of  claims 34  to  54 , comprising a deck ( 11 ) and a hull ( 9 ), wherein the deck is mounted on the hull and the hull is integrally formed with the straight runner means ( 19 ) and the one or more carved runners.  
     
     
         56 . A vehicle according to  claim 55 , wherein the hull ( 9 ) comprises a substantially cylindrical central portion and a pair of upwardly inclined tapered ends ( 27 ).  
     
     
         57 . A vehicle according to  claim 56 , wherein the tapered ends ( 27 ) are upwardly inclined at an angle (α) in the range 30° to 45°.  
     
     
         58 . A vehicle according to  claim 57 , wherein the tapered ends ( 27 ) are upwardly inclined at an angle (α) of 38°.  
     
     
         59 . A vehicle according to any one of  claims 34  to  58 , wherein at least a portion of the straight runner means ( 19 ) or the one or more curved runners is replaceable.  
     
     
         60 . A vehicle according to any one of  claims 34  to  59 , further-comprising an attachment point ( 2 ) for a leash ( 4 ).  
     
     
         61 . A hull ( 9 ) for a vehicle according to any one of  claims 55  to  60 .  
     
     
         62 . A hull according to  claim 61 , wherein the hull is formed from a moulded plastics material.  
     
     
         63 . A hull according to  claim 61  or  62 , for fixing to a deck ( 11 ), the hull comprising two mounting regions ( 113 ,  114 ) for attaching the hull to the deck by means of fasteners ( 14 ) passing through the deck.  
     
     
         64 . A hull according to  claim 63 , wherein one of the mounting regions comprises a plurality of mounting holes ( 113 ) and the other mounting region comprises a pair of slots ( 114 ) extending longitudinally of the hull.  
     
     
         65 . A hull according to  claim 61  or  claim 62 , further comprising attachment means for attaching the hull to a skateboard.  
     
     
         66 . A hull according to  claim 65 , wherein the hull is attachable to a skateboard by engaging the skateboard wheels.  
     
     
         67 . A hull according to  claim 65 , wherein the hull is attachable to a skateboard by engaging the skateboard axles.  
     
     
         68 . A vehicle according to any one of  claims 34  to  54 , wherein the straight runner means ( 19 ) is attached to the one or more curved runners by a space frame ( 123 ).  
     
     
         69 . A vehicle according to any one of  claims 34  to  54 , or  68 , adapted for use as a toboggan ( 120 ;  125 ).  
     
     
         70 . A vehicle according to any one of  claims 34  to  54  or  68 , adapted for use as an ice skating boot ( 130 ).  
     
     
         71 . A pair of vehicles according to  claim 70 , wherein the curvatures of the curved runners are arranged such that the curved runners of the two vehicles carve circles of different respective radii on the ice when the boots are inclined at the same roll angle.  
     
     
         72 . A vehicle according to any one of  claims 34  to  54 , or  68 , adapted for use as a ski for a snowmobile.  
     
     
         73 . A vehicle for travelling over a surface, and having a longitudinal axis about which the vehicle can roll relative to the surface, the vehicle comprising: 
 straight runner means comprising a row of wheels for travelling on the surface in a substantially straight line when the vehicle is at a first roll angle relative to the surface; and    two or more curved runners convex toward the straight runner means and each comprising an arcuate row of wheels arranged in an arc of substantially circular shape of a respective radius for travelling on the surface in a substantially circular path when the vehicle is at a respective roll angle relative to the surface,    characterised in that each of the curved runners has a tilt-radius product defined by the tangent of the roll angle associated with the curved runner multiplied by the radius associated with the curved runner, and wherein the tilt-radius products of the curved runners are substantially equal.    
     
     
         74 . A vehicle for travelling over a surface, and having a longitudinal axis about which the vehicle can roll relative to the surface, the vehicle comprising: 
 straight runner means comprising a row of wheels for travelling on the surface in a substantially straight line when the vehicle is at a first roll angle relative to the surface; and    two or more curved runners convex toward the straight runner means and each comprising an arcuate row of wheels arranged in an arc of substantially circular shape of a respective radius for travelling on the surface in a substantially circular path when the vehicle is at a respective roll angle relative to the surface,    characterised in that each of the curved runners has a tilt-radius product defined by the tangent of the roll angle associated with the curved runner multiplied by the radius associated with the curved runner, and wherein for any two curved runners having different associated roll angles, the tilt-radius product of the curved runner having the smaller associated roll angle is larger than the tilt-radius product of the curved runner having the larger associated roll angle.