【正文】
e or the plate chain drive. Furthermore, the individual drives are equipped with plaary gears, which causes relatively high costs. The object of the present invention is to create an improved multimotor drive for escalators, which can be implemented at favorable costs, which may be built up in a modular manner, and which covers a usual performance range. BRIEF DESCRIPTION OF THE INVENTION The drive according to the present invention distinguishes itself by several constructionally identical drive units being mountable distributed at the circumference of a main drive wheel, whereby the main drive wheel or its toothing need be dimensioned only for loading by a single drive unit. The main drive wheel itself thus can have a smaller width, which is of great advantage for the acmodation of the drive parts in the case of an escalator. The drive units, in a number corresponding with power requirements, may be flangemounted to a main gear housing identical for all performance classes. This simplifies the production process for the entire constructional series, reduces the inventory and facilitates maintenance and repairs. The drive units are provided with torque transmitters and/or rotational speed transmitters for recognition of their mechanical loading. Each of the drive units can furthermore be provided with a clutch which makes a selectable switchingin or switchingout of a drive unit possible. The drive further prises a frequencysetting device which is mon to all drive units and by means of which different speeds can be set and which also serves as a starting aid. A control and regulating unit produces corresponding control and regulating mands by the processing of ining data. The control and regulating unit causes the switchingin and switchingout of individual drive units on the basis of actual load data from the torque transmitters, which helps to improve the electrical and mechanical efficiency and thus also reduces the energy consumption. The use of polyphase alternating current squirrelcage motors of variable frequency and their associated control has the advantage that high torques can be produced at low rotational speeds. BRIEF DESCRIPTION OF THE DRAWINGS The invention is explained more closely in the following with the aid of an illustrative example of an embodiment thereof and is illustrated in the acpanying drawings, wherein: FIG. 1 shows an escalator with a drive according to the invention at the upper end of the escalator。 FIG. 2 shows the drive with drive units flangemounted on a main gear transversely to the direction of travel of the escalator。 FIG. 4 shows a threedimensional illustration of the drive arrangement according to FIG. 2。 and FIG. 6 shows a block schematic diagram and functional diagram of the drive with all associated ponents. DETAILED DESCRIPTION OF THE INVENTION FIG. 1 shows an escalator 1 with an upper end 2, below which drive units denoted by 7 and a part of a stair chain 3 are visible. FIG. 2 shows the details of a drive, which is installed within a carrying structure 9 at the upper end 2 of the escalator 1. Three identically constructe