Pivot joint and vehicles that employ a pivot joint

A foot-deck-based vehicle, comprising:

• a foot deck having a front end and a rear end;
• a front wheel assembly mounted at the front end of the foot deck and a rear wheel assembly mounted at the rear end of the foot deck;
• a handlebar mount on the foot deck and a handlebar that extends from the handlebar mount,
• wherein the handlebar mount defines a handlebar pivot axis and has a first handlebar mount engagement surface extending circumferentially about the handlebar pivot axis and having a first plurality of handlebar mount projections which alternate with a first plurality of handlebar mount valleys, wherein an axial height of the first plurality of handlebar mount projections above the first plurality of handlebar mount valleys is a first height,
• wherein the handlebar has a first handlebar engagement surface extending circumferentially about the handlebar pivot axis and having a first plurality of handlebar projections which alternate with a first plurality of handlebar valleys, wherein an axial height of the first plurality of handlebar projections above the first plurality of handlebar valleys is a second height,
• wherein the handlebar mount has a second handlebar mount engagement surface extending circumferentially about the handlebar pivot axis and having a second plurality of handlebar mount projections which alternate with a second plurality of handlebar mount valleys, wherein an axial height of the second plurality of handlebar mount projections above the second plurality of handlebar mount valleys is a third height,
• wherein the handlebar has a second handlebar engagement surface extending circumferentially about the handlebar pivot axis and having a second plurality of handlebar projections which alternate with a second plurality of handlebar valleys, wherein an axial height of the second plurality of handlebar projections above the second plurality of handlebar valleys is a fourth height;
• and
• a handlebar biasing member that urges the first and second handlebar engagement surfaces axially into engagement with the first and second handlebar mount engagement surfaces, respectively,
• wherein a greater of the number of first handlebar projections and the number of first handlebar mount projections is greater than a greater of the number of second handlebar projections and the number of second handlebar mount projections,
• wherein a lesser of the third and fourth heights is greater than a lesser of the first and second heights,
• wherein the handlebar is precessively pivotable about the handlebar pivot axis between a use position and a storage position, wherein the handlebar extends farther away from the foot deck in the use position than in the storage position,
• wherein at the use and storage positions the first handlebar projections engage the first handlebar mount valleys and the second handlebar projections engage the second handlebar mount valleys,
• and wherein, during pivoting of the handlebar between the use and storage positions, engagement of the second handlebar projections with the second handlebar mount projections substantially prevents engagement of the first handlebar projections with the first handlebar mount projections.