which are connected to one another at a base 16 the trapezoidal straps are held at an angle u03b1 relative to one another by means of struts 13 14 as shown the length of the base 16 is adjustable and thus adaptable to a diameter of the tubular knit the base 16 is connected by a strap 17 and a rotating bearing 18 to a lower section 20 1 of a central rod 20 the central rod 20 is fastened to a machine frame of the circular knitting machine the central rod 20 is oriented coaxially to a central axis of the circular knitting machine in this case a coupling unit 21 and a pivoting bearing 22 as shown in fig2 and 3 respectively are arranged between the lower section 20 1 of the central rod 20 and an upper section 20 2 of the central rod 20 as result of the pivoting bearing 22 the expander 10 can pivot in relation to the central rod 20 and thus move out of the way of forces that are exerted on it by the tubular knit not shown generated by the circular knitting machine these forces are thus not transferred to the central rod 20 the central rod 20.