1、The multi-motor drive DESCRIPTION: The present invention concerns a drive for an escalator, which drives the stair belt and is arranged on one or both sides of the escalator at the upper and/or the lower end thereof, wherein the drive comprises a main drive wheel and at least one motor with gear and
2、 brake components. BACKGROUND OF THE INVENTION Different dispositions and constructional principles are known for escalator drives. Since the drive must be designed for the maximally occurring load, a relatively large and strongly dimensioned motor with a corresponding gear is necessary. Poor effici
3、ency at the mostly prevailing partial load and the large installation volume in the case of limited space availability within an escalator construction are disadvantages of such a drive. These disadvantages are present to a lesser degree or not at all with multi-motor drives. Such a drive for escala
4、tors and walkways, which comprises two individual drives or two twin drives, the output gearwheels of which drive the stair chain or the plate chain and, by way of an additional gear, the handrail, is known from DE 35 26 905. Such a construction is executed in different variants and correspondingly
5、comprises a number of different gears and gear housings for the stair chain drive or the plate chain drive. Furthermore, the individual drives are equipped with planetary gears, which causes relatively high costs. The object of the present invention is to create an improved multi-motor drive for esc
6、alators, 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 mo
7、untable 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 accommodation of the drive parts in
8、 the case of an escalator. The drive units, in a number corresponding with power requirements, may be flange-mounted 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 mainte
9、nance 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 switching-in or switching-out of a drive unit possible
10、. The drive further comprises a frequency-setting device which is common 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 commands by the processing of incoming da
11、ta. The control and regulating unit causes the switching-in and switching-out 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 al
12、ternating current squirrel-cage 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 o
13、f an embodiment thereof and is illustrated in the accompanying 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 flange-mounted on a main gear transversely to the direction of travel of the escalator； FIG. 3 shows the drive with drive units flange-mounted on a main gear longitudinally of the direction of travel of the escalator；
