Interactive, computer based orthodontist treatment planning, appliance design and appliance manufacturing is described. In one embodiment, the assembly includes lighting components which are capable of projecting light toward a mail item in a viewing station at a specific angle, which angle may be adjusted to reduce the amount of specular reflection from an item toward a camera. One or more phase errors of a plurality of received symbols are generated. The delay filter is used to control the delay amount of the feedback signal so as to obtain the maximum value of the correlation value. For ease of manufacturing, machining and assembling, there is provided that at least five shafts selected from the group consisting of the crankshaft, the first gear shaft, the second gear shaft, the intermediate shaft and the balancer shaft be disposed in a first parting plane of a first and a second housing piece of the housing. According to the invention, the conveying speed of the first conveying device is synchronised with a movement speed of the gripping device.