Tilting wheeled vehicle

Abstract

A tilting, preferably three-wheeled, vehicle is disclosed that has a tilting mechanism that allows the vehicle to have leaning characteristics substantially similar to those offered by an in-line two-wheeled vehicle, but that does not require complex linkages and/or control systems to operate effectively. A tilting linkage is operably secured to a frame to allow a pair of spaced apart wheels to remain substantially aligned with the plane of the vehicle throughout its range of movement while still allowing the steering axes of each wheel to intersect the substantially vertical centerline of each wheel. The linkage also allows the caster angle of each wheel's pivot axis can be optimized independently of the angle of the vehicle's handlebar steering shaft.

We claim: 
     
         1 . A tilting wheeled vehicle having:
 an elongate frame defining a frame plane extending substantially vertically along a longitudinal centerline of said frame, said frame tillable from side-to-side defining a range of movement of said frame;   a tilting linkage operably secured to the frame, said tilting linkage operably securing a first wheel and a second wheel spaced apart from and aligned substantially parallel to said first wheel;   said first wheel pivotally secured to said linkage defining a first pivot axis and having a substantially vertical longitudinal centerline defining a first wheel plane that intersects said substantially vertical longitudinal centerline, said first pivot axis substantially intersecting said first wheel plane;   said second wheel pivotally secured to said linkage defining a second pivot axis and having a second substantially vertical longitudinal centerline defining a second wheel plane that intersects said second substantially vertical longitudinal centerline, said second pivot axis substantially intersecting said second wheel plane; and,   said first steering axis and said second steering axis aligned substantially parallel to said frame plane through said range of movement of said frame.   
     
     
         2 . The tilting wheeled vehicle of  claim 1 , wherein said frame has a front, a back, a left side, and a right side and said frame is tiltable so that said frame plane may tilt in the direction between said left side and said right side, and further including:
 a rear wheel operably secured toward the back of said frame;   said tilting linkage is operably secured toward the front of said frame thereby defining a tilting three-wheeled vehicle.   
     
     
         3 . The tilting wheeled vehicle of  claim 2 , wherein said tilting linkage includes:
 a substantially horizontal first pivot operably secured to the frame substantially near said longitudinal centerline of said frame;   a substantially horizontal second pivot operably secured to the frame substantially near said longitudinal centerline of said frame;   said first and second pivots spaced apart from each other with said first pivot positioned substantially vertically above said second pivot;   an upper arm pivotally secured to said first pivot and having a first distal end;   a lower arm pivotally secured to said second pivot and having a second distal end;   a kingpin extending between said upper arm and said lower arm toward said first and second distal ends, said kingpin aligned substantially parallel to the frame plane of the vehicle; and,   a wheel operably secured to said kingpin.   
     
     
         4 . The tilting wheeled vehicle of  claim 3 , wherein said upper arm has an opposite third distal end and said lower arm as an opposite fourth distal end, and further including:
 a second kingpin extending between said upper arm and said lower arm toward said third and fourth distal ends, said second kingpin aligned substantially parallel to the frame plane of the vehicle and said first kingpin; and, a second wheel operably secured to said second kingpin.   
     
     
         5 . The tilting vehicle of  claim 1 , wherein said vehicle is a conventional motorcycles and said linkage is detachably secured to said motorcycle. 
     
     
         6 . The tilting vehicle of  claim 2 , further including a steering shaft operably secured to said frame, said steering shaft aligned substantially parallel to said frame plane. 
     
     
         7 . The tilting vehicle of  claim 6 , further including a handle bar operably secured to said steering shaft, and a steering linkage extending between said steering rod and said first and second wheels so as to allow a rider to turn said first and second wheels about said first and second kingpins, respectively, by turning the handle bar about said steering shaft thereby steering the vehicle. 
     
     
         8 . The tilting vehicle of  claim 1 , further including a suspension system operably secured to said linkage. 
     
     
         9 . The tilting vehicle of  claim 8 , wherein said suspension system includes a compression spring operably positioned between said first wheel and said kingpin. 
     
     
         10 . The tilting vehicle of  claim 1 , wherein said tilting linkage includes:
 a substantially horizontal first pivot operably secured to the frame substantially near said longitudinal centerline of said frame;   a substantially horizontal second pivot operably secured to the frame substantially near said longitudinal centerline of said frame;   said first and second pivots spaced apart from each other with said first pivot positioned substantially vertically above said second pivot;   a first upper arm pivotally secured to said first pivot and having a first distal end;   a first lower arm pivotally secured to said second pivot and having a second distal end;   a first kingpin extending between said first upper arm and said first lower arm toward said first and second distal ends, said first kingpin aligned substantially parallel to the frame plane of the vehicle;   said first wheel operably secured to said first kingpin.   a second upper arm pivotally secured to said first pivot and having a third distal end;   a second lower arm pivotally secured to said second pivot and having a fourth distal end;   a second kingpin extending between said second upper arm and said second lower arm toward said third and fourth distal ends, said second kingpin aligned substantially parallel to the frame plane of the vehicle; and, said second wheel operably secured to said first kingpin.   
     
     
         11 . The vehicle of  claim 10 , further including a suspension system operably connected to said linkage. 
     
     
         12 . The vehicle of  claim 11 , wherein said suspension system is operably connected to said first upper and said second upper arm. 
     
     
         13 . A linkage for use in a tilting three-wheeled vehicle having a handle bar rotatable about a steering shaft and a substantially elongate frame defining a longitudinal plane along the centerline of said vehicle, said linkage having:
 a substantially horizontal first pivot operably secured to the frame substantially near said longitudinal centerline;   a substantially horizontal second pivot operably secured to the frame substantially near said longitudinal centerline;   said first and second pivots spaced apart from each other with said first pivot positioned substantially vertically above said second pivot;   an upper arm pivotally secured to said first pivot and having a first distal end;   a lower arm pivotally secured to said second pivot and having a second distal end;   a kingpin extending between said upper arm and said lower arm toward said first and second distal ends, said kingpin defining a first wheel steering axis aligned substantially parallel to the longitudinal plane of the vehicle;   a first wheel operably secured to said kingpin and having a substantially vertical longitudinal centerline defining a first wheel plane; and, said first wheel steering axis positioned substantially coincident with said first wheel plane.   
     
     
         14 . The linkage of  claim 13 , wherein said upper arm has an opposite third distal end and said lower arm as an opposite fourth distal end, and further including:
 a second kingpin extending between said upper arm and said lower arm toward said third and fourth distal ends, said second kingpin aligned substantially parallel to the longitudinal plane of the vehicle and said first kingpin; and,   a second wheel operably secured to said second kingpin and having a substantially vertical longitudinal centerline defining a second wheel plane; and,   said second wheel steering axis positioned substantially coincident with said second wheel plane.   
     
     
         15 . The linkage of  claim 13 , further including:
 a second upper arm pivotally secured to said first pivot and having a third distal end;   a second lower arm pivotally secured to said second pivot and having a fourth distal end;   a second steering shaft extending between said second upper arm and said second lower arm toward said third and said fourth distal ends, said second steering shaft aligned substantially parallel to the longitudinal plane of the vehicle; and,   a second wheel operably secured to said steering shaft.   
     
     
         16 . The linkage of  claim 15  wherein said linkage is detachable secured to the front of a conventional motorcycle. 
     
     
         17 . The linkage of  claim 16 , further including a suspension system operably secured to said linkage.