The multi-motor driveDescription: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 brake BACKGROUND OF THE INVENTION Different dispositions and constructional principles are known for escalator Since the drive must be designed for the maximally occurring load， a relatively large and strongly dimensioned motor with a corresponding gear is Poor efficiency 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 These disadvantages are present to a lesser degree or not at all with multi-motor Such a drive for escalators 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 Such a construction is executed in different variants and correspondingly comprises a number of different gears and gear housings for the stair chain drive or the plate chain Furthermore， the individual drives are equipped with planetary gears， which causes relatively high The object of the present invention is to create an improved multi-motor 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 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 The main drive wheel itself thus can have a smaller width， which is of great advantage for the accommodation of the drive parts in the case of an The drive units， in a number corresponding with power requirements， may be flange-mounted to a main gear housing identical for all performance This simplifies the production process for the entire constructional series， reduces the inventory and facilitates maintenance and The drive units are provided with torque transmitters and/or rotational speed transmitters for recognition of their mechanical 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 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 A control and regulating unit produces corresponding control and regulating commands by the processing of incoming 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 The use of polyphase alternating current squirrel-cage motors of variable frequency and their associated control has the advantage that high torques can be produced at low rotational 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 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; FIG 4 shows a three-dimensional illustration of the drive arrangement according to FIG 2; FIG 5 shows a three-dimensional illustration of the drive arrangement according to FIG 3; and FIG 6 shows a block schematic diagram and functional diagram of the drive with all associated 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 FIG 2 shows the details of a drive， which is installed within a carrying structure 9 at the upper end 2 of the escalator Three identically constructed drive units 7 drive a toothed main drive wheel 6 by way of an output gearwheel 6 and an intermediate gearwheel 21， and are arranged and distributed about the circumference of the main drive wheel The main drive wheel 6， together with a stair chain wheel 5， are fastened on the main shaft 4 of the The drive units 7 are firmly connected to a main gear housing 8 at three planar flange-connecting openings 24 formed for this When less than three drive units 7 are needed， the unused flange-connecting opening 24 may be closed by a cover and the associated intermediate gearwheel 21 is not With this construction， the same main gear housing 8 can always be used for one， two or three needed drive units The axles of the drive units 7 are arranged transversely to the direction of movement of the escalator 1， which yields the advantage of a short machine As example of a variant， FIG 3 shows an arrangement of the drive units 7 parallel to the direction of movement of the escalator In this manner of arrangement， the drive units 7 additionally comprise a bevel gear Motor 1， clutch 2， brake 4， flywheel 5 and the output gearwheel 6， which are otherwise constructionally identical with and incorporated in the drive units 7 of FIG 2， are present for each drive unit The main gear housing 8 is likewise always the same for one， two or three drive units 7 and unused flange-connecting openings 24 can likewise be covered by a FIG 4 is a spatial illustration of the drive according to FIG 2 within the carrying structure 9 of the escalator Two stair elements 22 are illustrated in addition to the elements shown in the preceding FIG 5 is a similar spatial illustration of the drive according to FIG 3 within the carrying structure 9 of escalator The two stair elements 22 are likewise additionally The function and operation of the multi-motor drive according to the invention is to be explained more closely in the following by reference to FIG The current supply of the drive takes place as usual from local three-phase current mains 13 with phases R， S and T which are led to a main switch Following thereon， the entire drive is connected through a main relay or several relays There then follows a frequency-setting device 16， which by way of a relay control 23 with the relays S1， S2 to Sn feeds the motors 1 (M1， M2 to Mn) of the drive modules 7 at a variable frequency current and direction of rotation as provided by the frequency-setting device The motors M1， M2 to Mn are， as already shown and described in the preceding， operatively connected with the main drive wheel 6 by way of gears 3 and output gearwheels 6 and intermediate gearwheels 21， which are not further illustrated Torque transmitters 20 (L1， L2 to Ln) for the purpose of the measurement of the actual mechanical loading of the motors M1， M2 to Mn are installed at a suitable place in the transmission between the motors M1， M2 to Mn as known in the The main gear wheel 6 drives a speed transmitter 19 by way of an appropriate known transmission， which similarly is not more closely A control and regulating unit 10 contains microprocessor and relay control components， as well as signal and data inputs and First input data line 1 supplies speed values from the speed transmitter 19， which are fed as actual values to an internal regulating The second group of input data lines 2 provide measurement values from the torque transmitters 20 and， through appropriate processing， cause the switching-in and switching-out of individual drive modules A third group of input data lines 3 supplies data from transmitters 11， which essentially concern control safety contacts and mode of operation A first group of output data lines 1 leads to the relays 15 and to the frequency-setting device A second group of output data lines 2 contain control signals for the relay control 23， and the third group of output data lines 3 provides the data to control optical signals and illumination The multi-motor drive according to the invention functions as following: During starting-up of the escalator 1， the relay 15 for the drive is switched on， the frequency-setting device 16 is run up and at least one drive module 7 is switched on by way of the relay control 23 by the control and regulating unit 10 according to the choice of direction and a start-up On reaching the target speed， the drive regulation in the control and regulating unit 10 holds the speed of travel of the escalator 1 constant within close limits independently of the During the now following operation of the escalator 1， the input data lines 2 from the torque transmitters 20 supply information about the mechanical loading of the switched-in drive modules 7 (motors M1， M2 to Mn) In the case of low or no loading by transported persons， the drive power of the first motor M1 may suffice， and the further motors M2 to Mn remain switched If a full loading with a tendency to lasting overload is signalled by the torque transmitter L1， the next motor M2 is switched on after a defined The signals from the two torque transmitters L1 and L2 are now monitored in the control and regulating unit 10 and a further， not illustrated motor M3 may be switched in according to analog criteria when the load limit values of the motors M1 and M2 are The third motor， denoted by Mn in the illustration， is to indicate that， in principle， a greater number of drive modules 7 can be For practical and economic reasons， however， the number of drive modules 7 will probably remain restricted to three or at most The procedure is reversed when the mechanical loading The no longer needed motors 1 are then switched off in the sequence beginning with the motor Mn switched on If a uniform wear of the drive modules 7 is desired， this can be taken into consideration by way of an additional measurement of the switched-on times of the individual drive modules 7 and the individual drive modules 7 can thus be switched on and off selectably and not according to an always identical As already mentioned， the number of the drive modules 7 is not limited to the illustrated three Drive modules 7 produced in large quantities can be very favorable in price， so that it could be feasible to provide a greater number， for example 4 to 6， drive modules With appropriately adapted control programs in the control and regulating unit 10， the greater amount of data resulting therefrom can be processed without The use of direct current motors for the drive modules 7 is also possible in principle with appropriately-adapted control and regulating techniques as known in the Alternating current motors with squirrel cage armatures are preferably used because of their simple mode of construction and ease of Moreover， efficient and likewise cheap frequency-setting devices or frequency converters are Normal spur gearwheels， by means of which an optimum mechanical efficiency is achieved， may be used for the drive arrangement according to FIG Cone wheel gears， by means of which a practically equal efficiency is achieved by comparison with spur gearwheels， are advantageously used as bevel gears 3 for the drive arrangement according to FIG The main gear housing 8 can be so constructed that both drive arrangements， those according to FIG 2 as well as those according to FIG 3， can be The main drive housing 8 then correspondingly has twice as many flange-connecting openings The intermediate gearwheels 21 can be the same at the same position for both drive The drive arrangement according to the invention can also be used for other kinds of conveying equipment， for example for walkways and mercalators in horizontal and oblique
