Abstract: An adjustable support mechanism for supporting a treatment device, and namely, a percussion generating tool having a treatment head and which is utilized by a patient to apply vibrations and percussion treatment to a predetermined area of his body. The support mechanism comprises an extendable boom which is pivotally secured at an attachment end to an adjustable pivoting housing which is securable to a stationary object. The pivoting housing permits vertical and horizontal angular displacement of the boom, and has an adjustable pressure biasing mechanism which acts on the boom to displace same vertically on a pivot connection to thereby apply a vertical moment on the load secured to the free end of the boom. An articulated connecting joint interconnects the treatment device to the free end of the boom. The connecting joint has a disconnectible brake to position the treatment device at a desired angle relative to the free end of the boom.