Assembly comprising - a first frame profile having several first orifices spaced apart from one another in its longitudinal direction, - a second frame profile having several second orifices spaced apart from one another in its longitudinal direction, - a conveying roller and - a pivot bearing, wherein the first frame profile and second frame profile extend at a distance, and wherein a second orifice lies directly opposite every first orifice respectively, and wherein a first orifice of the first frame profile co-operates with a first section of the conveying roller, and a second orifice of the second frame profile co-operates with a third section of the conveying roller, and wherein the conveying roller comprises a shaft and a roller body mounted so as to be rotatable about this shaft, and at least a first end of the shaft in the part protruding beyond the roller body has a first shoulder between the first section located on the roller side having a larger first cross-section and a second section lying opposite the first shoulder having a smaller second cross-section, - wherein the pivot bearing has an orifice that is pivotable about the pivot axis of the pivot bearing and oriented normally with respect thereto and which co-operates with the second section of the shaft, characterized in that - the orifice has a generally cylindrical shape, - the distance (a) between the first and second frame profile (13, 16) is dimensioned such that the first section and the third section of the shaft lie in directly opposite first and second orifices (14, 17) of the frame profiles (13, 16) when the conveying roller is mounted in a straight position and - the lengthways distance (b) of the first respectively second orifices (12, 17) is dimensioned such that when the conveying roller is mounted in an oblique position, the first section of the shaft sits in a first orifice of the first frame profile, the second section of the shaft sits in the cylindrical orifice of the pivot bearing mounted at the first orifice on the outside of the first frame profile, and the third section of the shaft sits in one of the first orifices lying obliquely opposite the second orifice in the second frame profile. - a first frame profile having several first orifices spaced apart from one another in its longitudinal direction, - a second frame profile having several second orifices spaced apart from one another in its longitudinal direction, - a conveying roller and - a pivot bearing, wherein the first frame profile and second frame profile extend at a distance, and wherein a second orifice lies directly opposite every first orifice respectively, and wherein a first orifice of the first frame profile co-operates with a first section of the conveying roller, and a second orifice of the second frame profile co-operates with a third section of the conveying roller, and wherein the conveying roller comprises a shaft and a roller body mounted so as to be rotatable about this shaft, and at least a first end of the shaft in the part protruding beyond the roller body has a first shoulder between the first section located on the roller side having a larger first cross-section and a second section lying opposite the first shoulder having a smaller second cross-section, wherein the first frame profile and second frame profile extend at a distance, and wherein a second orifice lies directly opposite every first orifice respectively, and wherein a first orifice of the first frame profile co-operates with a first section of the conveying roller, and a second orifice of the second frame profile co-operates with a third section of the conveying roller, and wherein the conveying roller comprises a shaft and a roller body mounted so as to be rotatable about this shaft, and at least a first end of the shaft in the part protruding beyond the roller body has a first shoulder between the first section located on the roller side having a larger first cross-section and a second section lying opposite the first shoulder having a smaller second cross-section, - wherein the pivot bearing has an orifice that is pivotable about the pivot axis of the pivot bearing and oriented normally with respect thereto and which co-operates with the second section of the shaft, characterized in that - the orifice has a generally cylindrical shape, - the distance (a) between the first and second frame profile (13, 16) is dimensioned such that the first section and the third section of the shaft lie in directly opposite first and second orifices (14, 17) of the frame profiles (13, 16) when the conveying roller is mounted in a straight position and - the lengthways distance (b) of the first respectively second orifices (12, 17) is dimensioned such that when the conveying roller is mounted in an oblique position, the first section of the shaft sits in a first orifice of the first frame profile, the second section of the shaft sits in the cylindrical orifice of the pivot bearing mounted at the first orifice on the outside of the first frame profile, and the third section of the shaft sits in one of the first orifices lying obliquely opposite the second orifice in the second frame profile.