bracket formed by a blade spring this clamping provides the friction enabling the suspension arm to convert the kinetic vibration energy into heat when the tub connected to this arm vibrates with high amplitudes the casing 14 is slotted over substantially its entire length up to portion 16 the slot is engageable by a pin 17 which belongs to the stop 12 and which is free to move up to the portion 16 which limits the maximum travel of the arm fig2 is a longitudinal sectional view of the suspension arm provided with two elastic means 18 19 which couple the tube to the body 10 in a preferred embodiment of the invention the body 10 which is adapted to slide on the tube 8 is elastically coupled to said tube by two elastic buffers 18 and 19 which comprise two helical springs in the present embodiment for this purpose other means may be considered the helical springs preclude shocks which may occur between the body 10 and the suspension member 4 or the stop portion 12 during operation of the suspension arm a single elastic means may be adequate if the elastic means is mechanically coupled either between the suspension.