The presence or absence of a connecting element, especially an insert for a rivet in the attaching of a carrier strap to a cardboard container, is determined by adjusting a lifting device with a scanning device to the article to be scanned and by arranging the lifting device and the scanning device so as to be jointly adjustable to the article to be scanned in time with rotation or movement of the processing machine (riveting machine) while the container is stationary on the rotary table of the machine.
