A locking mechanism for inner and outer telescoping members includes a housing fixedly attached to the axial outer end of the outer telescoping member. A cam member is mounted on the housing for pivotal movement between a locking position applying pressure urging a pressure pad in a radial through opening in the housing against the outer surface of the inner telescoping member to lock the inner telescoping member against axial movement relative to the outer telescoping member, and an unlocking position releasing the applied pressure.