A shock absorbing device uses a damper including a cylinder enclosing a viscous fluid; a piston rod; and a piston dividing the interior of the cylinder in two axially separated parts. The piston is connected to the piston rod and has an orifice communicating the two parts. The piston includes an inner member integrally connected with the piston rod, and an outer member disposed about an outer perimeter of the inner member and configured to be axially movable with respect to the inner member. The inner and outer members are configured to define a gap therebetween through which the viscous fluid can flow, and to be biased away from each other by a spring disposed therebetween. The inner and outer members are arranged so that the gap is reduced as the amount that the inner member protrudes into the outer member increases, to thereby define a variable orifice.