one another in a direction perpendicular to the travel direction of the flat bars 14 the respective sensor surfaces 19 u2032 19 u2033 and 19 u2032 u2033 are oriented towards the clothing 20 of the momentarily adjoining flat bar 14 and are spaced at a distance a from the clothing 20 fine threaded adjustment nuts 21 a 21 b and 21 c provide for a setting of the distance a for each sensor relative to the clothing 20 the sensors 19 a 19 b and 19 c are secured in a holding device 22 which is secured stationarily to the machine frame by screws 23 a and 23 b turning to fig4 an evaluating device 26 is connected to the sensor 19 by a conductor 25 and displays and stores the magnitudes detected by the sensor 19 the evaluating device 26 is further connected with an electronic card control device 27 which emits signals for the setting device 28 for adjusting the carding gap between the clothing 20 of the flat bars 19 on the one hand and the clothing 4 u2032 of the carding cylinder 4 on the other hand at the same time this information is also applied to a carding information system which may be a kit model manufactured by tr u00fctzschler gmbh amp co kg and which forms part of a computer and display device 29 where the data of an entire carding group are monitored structural features relating to mechanisms for adjusting the working distances for example by means of radially shifting the support for the slide guide 22 in the working zone as a function of sensor signals are disclosed for example in.