stop and enabling extension 8 to slide axially to a certain limit in either direction through the opening 7 annular flange 10 prevents protruding coaxial extension 8 from escaping inopportunely from its sliding insertion thus maintaining the connection between the two sections 1a and 1b of compression shaft 1 when the spring column is at rest an intermediary space 11 provides the appropriate separation depending on the features which the conical spring column is constructively required to have this space is provided between platform 9 of internal section 1a of compression shaft 1 and the lower surface of internal transverse baffle 6 of external section 1b the purpose of space 11 is to enable section 1a to slide coaxially with respect to section 1b of compression shaft 1 when section 1b of compression shaft 1 moves coaxially in the downward direction as the result of vertical pressure applied to the shield of the upper end of spring column 2 central baffle 6 of external section 1b comes to press on platform 9 the latter being one of the stops that limits the downward path of external section 1b with relation to internal section 1a the u shaped notches 5 in external section 1b of compression shaft 1 when both sections 1a and 1b are mutually connected with axial sliding capability are inverted to open downwardly toward section 1a during the coaxial sliding of one section 1b with relation to the other section 1a or shaft 1 u shaped notches 5 slide along blocks 4 of section 1a until the bottom of each inverted u in.