The invention relates to an apparatus at a carding machine, wherein at least one stationary carding segment comprising a carrier together with at least one carding elements is associated with a roller, for example a cylinder. 
In a known apparatus at least two carding elements are arranged behind one another in the direction of rotation of the roller, and the clothings of the carding elements and the roller clothing are located opposite one another.  According to EP 0 431 482, a plurality of stationary carding segments, each comprising three fixed carding elements, are associated with the cylinder of the carding machine, each of them being fastened by means of end parts to the associated side frame of the carding machine.  The mounting surfaces for the three fixed carding elements on a carrier are so matched to the curvature of the cylinder that, when the carding segment has been optimally set, the width of each carding element extends perpendicular to a respective radius of the cylinder.  The carding surfaces of the carding elements are accordingly, in each case, oriented parallel to a corresponding tangent at the clothing of the cylinder.  Re-setting can be so performed, for example with the aid of a suitable gauge, that the clothing of one of the carding elements has a desired spacing from the clothing of the cylinder.  However, in all probability, the clothings of the other two carding elements will not then have the desired spacing from the cylinder clothing.  The desired setting is achieved by means of a pivoting movement of the carding segment about a predetermined axis.  During that pivoting movement, all three inter-connected carding elements are displaced until the desired setting has been achieved, at which setting the width of all the carding elements extends perpendicular to a respective radius of the cylinder.  The complexity of the construction for pivoting and fixing the carding segment is disadvantageous.  It is also disadvantageous that orientation of the carding elements parallel to a respective tangent at the roller results in increased fibre damage and nep formation.  Finally, the clothings of the carding elements are subject to considerable wear in operation. 
It is an aim of the invention to provide an apparatus of the kind described at the beginning which avoids or mitigates the mentioned disadvantages and which especially is simple in terms of construction and installation, enables individual setting of the carding intensity and makes possible a reduction in wear on the clothings of the carding elements.