A stand for supporting a machine includes a mounting support having legs, at least one wheel unit having a wheel holder connected to one leg by a pivotal shaft thereof and a caster or wheel connected to the wheel holder, an actuating member connected at a first pivotal location thereof to the mounting support and at least one link having an end pivotally connected to the wheel holder. The connection location of the wheel and the pivotal shaft are spaced. The connection location of the end of the link and the pivotal shaft are spaced. The other end of the link is pivotally connected to the actuating member. The connection location of the other end of the link and the first connection location are spaced. When the actuating member is pivoted, the wheel holder is pivoted by the link to move the wheel downward to engage the ground.