Adjustable-height seat device

An assembly method of an adjustable seat device for a vehicle comprising the steps of;

• providing a base portion,
• providing a seat portion that is movable with respect to the base portion between a first retracted position, and a second extended position,
• providing an articulation system forming a deformable parallelogram, which is connected to the base portion-and to the seat portion and comprising at least one diagonal support arm connected diagonally to the deformable parallelogram,
• wherein the diagonal support arm has a first length when the seat portion is in the first retracted position and a second length when the seat portion is in the extended second position,
• providing first locking means arranged to lock the diagonal support arm in the second length when the seat portion is in the second extended position, and arranged to engage and withstand a first normal use force applied to the seat portion,
• providing second locking means arranged to lock the diagonal support arm in the second length when the seat portion is in the second extended position, and arranged to engage and withstand a second vehicle impact force, greater than the first force, applied to the seat portion,
• wherein the second locking means are engaged only when the second force is applied to the seat,
• further comprising a step of assembling a pivot joint of the deformable parallelogram, comprising the steps of:
• inserting a rectilinear portion of an elastic return element forming a hinge axis into at least one female portion of each of the parts connected to the pivot joint, so as to form a hinge,
• plastically deforming a free end of the rectilinear portion to form a folded end, so as to make the elastic return element of the formed hinge irremovable,
• hooking the folded end to one of the parts connected to the pivot joint, and
• tensioning the elastic return element prior to hooking the folded end to one of the parts connected to the pivot joint.