a wear plate 41 the stop roller 34 rolls on the wear plate 41 since the mould reciprocates in the direction of the arrows 45 and 46 this stop roller 34 serves mainly to guarantee a precise positioning of the copper plate 50 and the rollers 1 relative to one another during operation of the plant which position is given by the exact distance 56 when an operational load 60 is applied to the frame 2 the self locking intermediate gearing 32 prevents the frame 2 from being pushed away from the slab i e the stop 40 the stop roller 34 and the intermediate gearing 32 guarantee that the frame does not change its position during casting something that is necessary for obtaining a perfect quality slab an indicator means may be present showing the exact position of the supporting rollers in case of a disturbance during operation e g a breakthrough of steel only the screws 20 between the intermediate piece 15 and the displacement ruler 16 need be released in order to separate the frame and intermediate piece from the ruler 16 alternatively the safety platelet 19 can be screwed off or knocked off whereupon the frame can be removed by being lifted from the double hook shaped quick lock this rapid detachment can be carried out so quickly that destruction of the displacement ruler and the adjustment mechanism can be prevented of course other known drive means can be substituted for the toggle lever linkage adjustment means shown in the drawings thus it is possible to arrange.