Wheelchair for transporting or assisting the displacement of at least one user, particularly for handicapped person

A wheelchair for transporting or assisting the displacement of at least one user, particularly a handicapped person or a child, comprising a chassis equipped with wheels and with a support means for supporting at least a portion of the user's weight when the wheel chair is moving on a ground, said chassis comprising:

• a first chassis portion supported by the ground and equipped with two main wheels rotatable around a common transverse main axis and with at least one front caster wheel located in front of said main axis;
• a second chassis portion designed to be supported by both the first chassis portion and the ground and being equipped with at least one rear caster wheel located behind said main axis, each rear caster wheel being mounted to an arm forming said second chassis portion, said arm being connected to said first chassis portion by a main articulation having an axis parallel to said main axis;
• energy accumulator means connected to said first and second chassis portion for storing mechanical energy when said at least one rear caster wheel is raised above a plane of a supporting surface defined by said main and caster wheels of said first chassis portion, said energy accumulator means comprising at least one spring capable of exerting a variable force on said arm as a function of the position of said arm with respect to said first chassis portion, said spring being located in a housing containing a bearing of said main articulation.