also integrally formed and support the bar 22 of the base profile section 21 which is connected on the external wall if the guide plate 45 is inserted into the support part tp and the guide plate 48 is inserted into the mounting part ap of the base profile section 21 thus the guide plate 45 abuts on the internal wall of the crossbar 22 and the guide plate 48 abuts in the mounting part ap on the separating crossbar 25 the attachment plate 41 supports attachment borings 50 which are positioned according to the distribution of the screw mountings into the connection bars 28 29 31 and 32 with the attachment screws 51 and through the interposition of the disks 52 the attachment plate 41 is bolted with the front side of the base profile section the guide plates 45 and 48 as well as the support attachments 47 produce an unequivocal coordination between the joint part and the base profile section 21 the guide plate 48 or adjusting plate has the threaded boring 49 into which the adjusting screw 53 is screwed the attachment surface of the attachment plate 41 is slightly inclined specifically in such a manner that there is an inclination of approximately 2 degrees to the opened mounting part ap the angle of inclination of 2 degrees is maintained between the front side of the.