Drive device and method

Abstract

Drive device (V), in particular a transport device of a container treatment plant (M), with at least one endless drive element (1) that can be driven to a movement and is subject to elongation during operation, wherein section markings (9, 9') and a start marking (10) are provided distributed along the drive element (1), wherein a encoder (C) generating displacement increments (16) synchronously with the movement of the drive element (1) and at least one stationary marker reader (AB) generating transmission signals (11, 12) are provided and are connected to a computer unit (CU) for signal transmission, which is designed to calculate the elongation either in sections (x, a - e, e') between the section markings (9) and / or in the drive element (1) by means of computational processing of the displacement increments (16) and the transmission signals (11, 12), characterized in thatthat the start mark (10) is formed by one of two section marks (9, 9') provided at a short distance from each other in the direction of movement (24) of the drive element (1), and that a common mark reader (AB) is provided for the section marks (9, 9') and the start mark (10).

Description

[0001] The invention relates to a drive device according to the preamble of patent claim 1 and a method according to the preamble of patent claim 9.

[0002] In container treatment systems, each container is transported, for example for inspection or treatment at a specific position, on transport devices moved by at least one drive element. The container is monitored or tracked by a computer unit, e.g. with respect to at least one reference position, with regard to the distance traveled or the respective position, for example in order to specifically separate out a dirty and / or damaged container or to treat each container at a specific position. In this case, travel increments are generated and evaluated from the movement of the drive element; these are generated by a sensor, e.g. a rotary encoder. The sensor can be installed on a pull shaft of the drive element and connected to the associated computer unit.Due to operational stress and wear, the drive element, which can be a link chain, for example, elongates on one side and / or as a whole. Due to elongation, exact tracking or position determination based solely on the path increments is no longer reliable, since the encoder generates the path increments under the assumption that the drive element is not elongated. In principle, a total elongation of up to approximately 3% can be tolerated. After this time, the drive element must be replaced. For a drive element with a length of 10.0 m, for example, such elongation means an offset of a transported container of up to approximately 30 cm compared to its position with an unelongated drive element. In practice, it is common practice to change path-specific parameters of the drive element from time to time for correct container tracking in a container handling plant, e.g.on the computer unit, which, however, is only a compromise in the case of uneven and continuously increasing elongation. The readjustment is carried out by service personnel either on-site or via a remote service facility, which entails high costs and potentially lengthy operational interruptions, and even then remains only a temporary compromise because elongation of the drive element occurs uncontrolled, unevenly, and continuously.

[0003] To solve this problem, measurement using light barriers on the containers on the transport devices in a container handling plant has already been considered in order to avoid the distorting influence of operational elongation of the drive element. However, other factors can distort the position or distance determination of each container, such as the lubrication of the drive element or the transport devices, slipping of each container during the conveying movement, displacement of the container due to friction on guide rails or similar, erroneous measurements due to changes in speed, e.g., on ramps and / or curves, and different container shapes. There is therefore a sustained need to avoid the influence of uncontrolled elongation of the drive element on the precision of position or distance determination.

[0004] The problem caused by elongation is also generally a critical factor for operational safety in drive elements of engines, machines or vehicles.

[0005] In the device known from US Pat. No. 5,490,590 A for detecting chain elongation in a drive device, a first mark reader detects the passage of chain pins, and a second mark reader detects the passage of a start mark. The control system linked to both mark readers can calculate the chain elongation from these signals.

[0006] The drive device according to JP H07-137 976 A uses a mark reader which, for the assigned control system, detects the passage of marks placed on the chain at equal longitudinal intervals.

[0007] According to DE 102 45 323 A1, a speed and / or elongation of the chain of a drive device is determined by means of first and second sensors which are stationary and placed next to the chain at a predetermined distance from each other.

[0008] The invention is based on the object of creating a drive device and a method that precisely determine and / or correct operational elongation and prevent damage or malfunctions caused by elongation. A secondary aspect of this object is to prevent undesirable effects of this elongation on operational reliability, despite unavoidable elongation of the drive element controlling a container transport, in order, for example, to increase operational reliability in such container processing plants and / or to minimize the rate of container rejection due to incorrect position or distance determination.

[0009] The stated problem is solved with the features of patent claim 1 and the features of patent claim 9.

[0010] Through the functional interaction between the encoder generating the travel increments, the single mark reader reading the markings and generating passage signals, and the computer unit, an operational elongation of the drive element can be precisely determined permanently or periodically without having to directly scan each container, in order to assess the risk of damage, malfunction, or unjustified container rejection and / or to avert it in good time. The single mark reader, as a sensor, uses the generated passage signals to not only map the extent of any elongation that has occurred, but also the location of the elongation within the drive element, so that the computer unit is able to precisely calculate the correlation between the travel increments and each point along the drive element, so that not only the extent of the elongation can be precisely determined, but also, for example,in a container handling system, each container can be correctly tracked and / or positioned despite elongation or even if the drive element is elongated on one side. Any elongation that has occurred can be detected and / or corrected periodically or permanently and automatically or manually, or operator-guided, e.g. via teleservice. The through signals are, so to speak, feedback signals corresponding to the actual mechanical conditions regarding the distance traveled at a point on the drive element, which is theoretically determined by simultaneously counting the distance increments. If the number of distance increments increases between two feedback signals compared to an initial number when the drive element is not elongated, the increase represents elongation, which is correctively taken into account by the computer unit when determining the distance traveled.The actual distance traveled by a point on the drive element, which would only correspond to a certain number if the distance increments were counted, thus corresponds, when the drive element is elongated, to a number of distance increments greater than the increase determined via the feedback signals. When assessing or averting a threat to the operational safety of the drive device, the elongation-related increase and / or the greater number of distance increments due to elongation can be taken into account accordingly, for example, to determine the position and / or distance with the greatest possible precision despite elongation. A common marking reader is expediently provided for the section markings and the start marking. This reduces the equipment required for the drive device.

[0011] The drive device can also be integrated, for example, in a machine, an engine or a vehicle such as a motorcycle, i.e. generally in a dynamic system in which operational safety is endangered by elongation of the drive element. In an internal combustion engine, the drive element can be, for example, a timing chain which has to control a certain timing, e.g. between the crankshaft and camshafts. This timing can be corrected, for example mathematically, after the elongation has been determined. In a motorcycle, the drive element can be the drive chain, which increases the risk of accidents or can impair handling if it elongates on one side. Once the elongation has been determined, a warning can be derived, or the drive engine can be switched off if a certain extent of elongation is reached.In a container handling plant, for example, the drive element is responsible for transporting containers to, from, or into specific stations. The travel increments and transit signals, taking into account the determined elongation, enable the distance and / or position of each container to be determined very precisely. The invention thus creates a simple tool for precisely determining elongation and either initiating countermeasures in a timely manner or eliminating the risk to operational safety, e.g., computationally compensating for the elongation. The transit signal of the start marker, which represents a starting point of the drive element, is of key importance here. Starting from the starting point, when the drive device is first put into operation, the length of the individual sections defined by the transit signals of the section markers is determined in travel increments.First, the length of each section is determined, as the markings on the drive element cannot naturally be evenly spaced. Sections of equal length would be virtually impossible from a manufacturing perspective and, with a typical encoder travel increment resolution of approximately 0.5 mm per increment, would be highly error-prone. Any elongation occurring during operation would then lead to an increase in the number of travel increments in one or more sections compared to the initial commissioning. This increase is then taken into account by the computer unit, i.e., determined, and, if necessary, compensated for.

[0012] In a suitable embodiment of the drive device, the computer unit can computationally compensate for elongation during a path-increment-related position and / or distance determination of at least one point on the drive element within a path section traversed during movement. Thus, elongation has no influence on the precision of the position and / or distance determination. This is particularly useful in a container processing plant when tracking each container transported by the drive element.

[0013] In a suitable embodiment, the drive element is also a link chain, preferably an endless link chain driven by a tension shaft with connecting pins between link plates. The encoder generating the travel increments is installed on the tension shaft and is preferably a rotary encoder. Alternatively, the drive element could also be a toothed belt or a technically equivalent element. The single mark reader can operate electrically, electromagnetically, electro-optically, inductively, capacitively, or even mechanically.

[0014] In a suitable embodiment, the segment markings and the start marking are distinguishable, readable parts of the link chain itself and / or projections and / or bores and / or permanent magnets and / or RFID links and / or reflectors or color marks on the link chain.

[0015] The markings on a link chain that can be read by a reader can also be chain parts (e.g., chain link, link plate, connecting pin) that differ from other, similar chain parts, e.g., due to their material or their magnetism. In a stainless steel link chain, this could be an iron chain link, a magnetic or magnetized chain link, or a magnetic or magnetized link plate or a connecting pin.

[0016] The start mark is formed by one of two section marks arranged closely spaced one behind the other in the direction of movement of the drive element. This is convenient from a manufacturing perspective and requires only one reader. The direction of movement of the drive element is irrelevant.

[0017] The starting marker can be conveniently identified by a specific section or a section marker within that section. This section differs, e.g., in length, from all other sections that are approximately equal to each other or less different than the one section.

[0018] In a suitable embodiment, a service area is also provided on the drive device for access to the drive element and / or at least one section positioned in the service area. If, for example, a one-sided elongation of a certain degree is detected, the drive element can be automatically or operator-guidedly placed in the service area with the elongated section, thereby reducing maintenance or repair times.

[0019] In order to at least simplify the determination of elongation on the control side, it can be useful if the sections between the section markings are approximately the same length, although sections of different lengths can also be useful. In this case, the distance between the start marking and an adjacent section marking, seen in the direction of movement, should preferably be shorter than the distance between the section markings of this section. This is particularly useful if only one mark reader is used and the start marking is formed by a second section marking. In order to identify the start point of the drive element, only a comparison with the path increments that are already present needs to be carried out. If a through signal then occurs again within just a few path increments, this clearly represents the start point or start position.The next section marker is in any case further away from the previous section marker than the further section marker forming the start marker.

[0020] In a suitable method variant, the computer unit uses the path increments to determine the position and / or distance of at least one selected point of the drive element within a path traversed by the drive element during its movement, preferably with reference to at least one reference position. During this position and / or distance determination, a determined elongation is simultaneously computationally compensated, so that the position and / or distance determination is consistently precise regardless of the extent of the elongation or the location of the elongation within the drive element.

[0021] In another process variant, the individual elongation of each section and the position of the section in the drive element relative to the start mark are determined, and the individual elongation of each section is individually compensated for by calculation when determining the position and / or distance. This results in greater precision in determining the position and / or distance. Furthermore, it is possible to identify the position of this section within the drive element when a predetermined degree of individual elongation is reached, for example, to facilitate maintenance or repair.

[0022] In a further expedient method variant, when a predetermined extent of the determined individual elongation of a section is reached, this section is moved to a service area of ​​the drive device before the drive element is stopped in order to be able to carry out maintenance or repair more quickly.

[0023] Alternatively or additionally, it may be expedient to generate an alarm signal and / or to stop the operation of the drive device when a predetermined determined elongation of the drive element and / or a section is reached.

[0024] Another useful method variant is particularly suitable for a container processing system in which the drive element drives a container transport device, for example, in an inspection or washing machine, or in a feed or discharge conveyor of such a machine, so that each transported container can be precisely tracked via the computer unit by mathematically compensating for the determined elongation based on the path increments. In this way, for example, in an inspection machine, it is possible to sort out a container identified as defective during an inspection at exactly the right point along a discharge conveyor, or in a washing machine, to position each container precisely in the washing station.

[0025] Embodiments of the subject matter of the invention are explained with reference to the drawings. They show: Fig. 1 schematically shows a drive device in side view, for example as part of a container treatment plant, Fig. 2 in assignment to Fig. 1 three signal curves below each other, Fig. 3 three different evaluation schemes I, II, III for the signal curves of Fig. 2, Fig. 4 a schematic plan view of an embodiment of a drive element as a link chain with section and start markings and associated marking readers provided thereon, and Fig. 5 is a plan view of another embodiment of a drive element in the form of a link chain with section and start markings provided thereon and a single marking reader, wherein in association with the drive element below two signal chains are provided as a replacement for the Fig. The three signal chains indicated in Figure 2 are shown.

[0026] Fig. Fig. 1 illustrates a drive device V in a schematic side view, which is integrated, for example, in a container treatment plant M with, for example, an inspection or washing station 8, wherein Fig. 1 in the Fig. 2 and Fig. 3 illustrations for explaining a method at least for determining an elongation of a drive element 1 are assigned.

[0027] The drive element 1 is endless and, for example, a link chain 17 ( Fig. 4, Fig. 5) or a toothed belt or a technically equivalent element which, during operation of the drive device V, undergoes elongation which progresses and may be uneven or one-sided over the entire length of the drive element 1. The drive element 1 can be driven for movement via a tension shaft 2 and a drive D and is guided via deflection elements 3, 4, e.g. sprockets. The drive element 1 drives a transport device 5 for containers 6. The position of the container 6 or the reference position 7, its axis and / or the distance traveled by the transport device 5 up to that point is tracked or determined via a computer unit CU. The container treatment system M can contain an inspection or washing machine IW as a non-limiting example.

[0028] Section markings 9 are arranged on the drive element 1 at substantially equal or unequal intervals. Furthermore, a single start marking 10 is provided on the drive element 1. The passage of the markings 9, 10 is Fig. 1 is monitored by separate stationary readers A and B, which generate transit signals 11, 12 and transmit them to a computer unit CU. For example, a sensor C, preferably a rotary encoder, is installed on the pull shaft 2. Synchronized with the movement of the drive element, it generates path increments 16 at equal intervals and transmits them to the computer unit CU. The section markings 9 divide the drive element 1 into second to fifth sections a - e, while a section marking 9 and the start marking 10 arranged a short distance from it define a first, relatively short section x.

[0029] The drive device V is expediently assigned at least one service area 22 in which access to the drive element 1 is possible and which is, for example, at least as long as the longest section, for example in order to be able to carry out maintenance or repair work on the drive element 1, e.g. to replace an excessively elongated section.

[0030] In the embodiment in Fig. 1, the pull shaft 2 is driven counterclockwise, for example.

[0031] In Fig. 2, a signal chain 13 illustrates the passage signals 11 of the section markings 9 generated by reader A, wherein each passage signal 11 has a width, for example, corresponding to the distance between two consecutive path increments 16 of the sensor C. The distance between the consecutive passage signals 11 corresponds to a specific number of path increments 16. The underlying signal chain 14 represents the passage signal 12 of the start marking 10 emitted by reader B. The passage signal 12 also has a width, for example, corresponding to the distance between two consecutive path increments 16 of the sensor C. The path increments 16 are represented in the underlying signal chain 15 of the sensor C.

[0032] Fig. 3 illustrates three different evaluation schemes I, II, III of the through signals 11, 12 and the path increments 16 by the computer unit CU.

[0033] In the upper scheme I in Fig. 3, the number of path increments 16 for the first section x is determined as soon as, after reader A responds to a section marking 9, reader B responds to the start marking 10 within three path increments 16. The length of the second section a is then determined as soon as reader A responds again within nine path increments 16. The length of the third section b is then directly determined as soon as reader A responds again within fifteen path increments 16. In this way, the length of each section x, a - e is continuously determined.

[0034] Knowing the starting position, i.e., the passage signal 12 of the start marker 10, the length of the individual sections is determined in travel increments 16 during initial commissioning of the drive device, specifically for each section. This is because, for manufacturing reasons, the section markers 9 cannot be arranged at exactly the same distances. However, at least theoretically, it is conceivable to arrange the section markers 9 at equal distances. Then, it would be sufficient to determine only the length of a section a - e in travel increments 16 during initial commissioning and to multiply the determined length by the number of sections to simplify calibration during initial commissioning.

[0035] When the position and / or distance of each container 6 is determined during operation of the drive device V via the computer unit CU, for example in relation to the reference position 7, not only are the distance increments 16 processed, e.g. counted, but the through signals 12, 11 are also taken into account and processed as feedback representing the actual mechanical conditions of the drive element 1, from which not only the overall elongation of the drive element 1 that occurs but also the individual elongations of the sections and the relative positions of the sections in relation to the starting point are determined and taken into account for the precise position and / or distance determination in such a way that they do not have a distorting influence. Distance-specific parameters of the drive element 1 are, so to speak, mathematically recalibrated relative to the situation during initial commissioning, taking into account the elongation that has occurred.

[0036] In the evaluation scheme II in Fig. 3, the number of each segment x, a', b', etc. is also determined via the number of path increments 16, in each case starting from the starting point, ie starting from the occurrence of the through signal 12 of the start marking 10. In this case, the sections a', b' are measured overlapping one another in order to determine, for example, the actual number of path increments 16 per section via the respective difference.

[0037] In the third evaluation scheme III in Fig. 3, the first section x is not evaluated directly in relation to the number of path increments 16, but the sections e', a' and b', etc., are determined in parallel and overlapping manner over the path increments 16, whereby the second section a' is started at the starting point, i.e. with the passage signal 12 for the start marking 10, and the number of path increments 16 is counted until the reader A responds again to the passage of the next section marking 9. The length of section x does not need to be taken into account directly in this case because it is irrelevant with regard to any elongation occurring there, and this elongation can be taken into account anyway by determining the elongation of section e'.

[0038] In Fig. In Figure 3, the evaluation schemes I, II, and III are separated from each other by dotted lines. The evaluation schemes discussed so far represent only a non-limiting selection from many different computational possibilities.

[0039] Fig. 4 illustrates a plan view of the drive element 1 analogous to that in Fig. 1, ie with two separate stationary readers A and B, of which reader A reads the section markings 9 arranged in one movement track, whereas reader B reads the start marking 10 arranged in another movement track. Provided that the section markings 9 and the start markings 10 are clearly distinguishable from each other, readers A and B and the markings 9, 10 could be placed in the same movement track, and not as in Fig. 4, on opposite sides and / or movement tracks of the drive element 1.

[0040] The Fig. The drive element shown in Figure 4 is a link chain 17 with links 18 and link plates 19, which are movably coupled relative to one another via connecting pins 20. The section markings 9, like the start markings 10, can be clearly legible parts of the link chain 17 itself, e.g., extended ends of the connecting pins 20 or projections on the links 18, but could also each be formed as a bore, permanent magnet reflector, color mark, or RFID link 21 and attached to the link chain 17. Chain parts themselves could also define a readable marking 9, 9', 10, e.g. by being made of a material different from that used in further such chain parts, or by having magnetic properties that are not present in further such chain parts (e.g. chain link 18 made of iron, possibly magnetized, or link plate 19, or connecting pin 20 in a stainless steel link chain).

[0041] Readers A and B or a single reader AB (see Fig. 5) for both markings 9, 9', 10 can operate electrically, electro-optically, electromagnetically, inductively, magneto-restrictively, or even mechanically or fluidically. Reed or Hall sensors can be used particularly effectively here. A double arrow 24 points in the Fig. 4 and Fig. 5 indicates that the link chain 17 can move in one direction or the other in the reading area.

[0042] In Fig. 5, the drive element 1 is also a link chain 17, again with chain links 18 and link plates 19 and connecting bolts 20, although here only a single stationary reader AB is provided, which reads the section markings 9 and the start marking 10 in the same movement track on the link chain 17. The start marking 10 is defined here by a second section marking 9' arranged a short distance adjacent to a section marking 9, which is identical to the section markings 9, but whose distance from the adjacent section marking 9 is smaller than the distance between two section markings 9 each defining a section. The computer unit CU identifies the second section marking 9' as the start marking 10 due to the smaller distance or the smaller number of path increments 16 after passing, for example, the previous section marking 9.

[0043] Another possibility for the computer unit CU to read or identify the start marking 10 is when one section of the drive element 1 defined by section markings 9, 9' differs significantly from the remaining sections, e.g., in terms of length, i.e., is noticeably longer or shorter, or read differently than the remaining sections. The start signal can then be derived from the passage of this different section, either solely due to the detected difference compared to all other sections, or due to the detected difference and one or both of the read section markings.

[0044] The Fig.The signal chains 13' and 15 arranged in FIG. 5 below the top view of the link chain 17 represent the passage signals 11, 12 of the common reader AB and the path increments 16 generated by the sensor C in the signal chain 15, with equal spacing between them. The section x is determined by the reader AB, after responding to the section marking 9 with the passage signal 11, responding again within three path increments 16 and then to the start marking 10 or the second section marking 9' forming it, so that the passage signal 12 can be identified to determine the start position. The length, here for example of the fifth section e, is determined by counting the path increments 16 between the responses of the readers A, B to the two consecutive section markings 9, here for example within thirty path increments 16.It is expedient for the number of path increments 16 between the section markings 9 in any section of the link chain 17 not to be approximately equal to or less than the number of path increments 16 between the section marking 9 and the start marking 10 assigned to it or the second section marking 9' forming the start marking 10.

[0045] The processing unit CU can be a computerized processing unit or a PLC controller. The movement speed of the drive element 1 in a container treatment plant can be, for example, 1.5 m to 2.0 m per second.

[0046] The evaluation of the through signals 11, 12 taking into account the path increments 16 can be carried out during operation of the drive device permanently or periodically and automatically and / or operator-guided in order to determine the elongation of the drive element 1 as a whole and / or individually in each section, and, preferably, to take this into account in the position and / or path determination, so that the elongation does not have a distorting influence or the computer unit CU is recalibrated each time.

[0047] However, the drive device V could also be used in a machine, an internal combustion engine, or a chain-driven vehicle such as a motorcycle, in order to prevent or minimize a reduction in operational safety caused by elongation. The drive element 1 could then, for example, be a timing chain of an internal combustion engine, which must control a specific timing between the crankshaft and camshafts or valves, whereby the timing could be mathematically adjusted after elongation is determined. In a motorcycle, a measured elongation could be used as a reason to generate a warning signal or to stop the operation of the motorcycle. In a machine, the drive element could also be monitored for elongation as a drive chain in a transmission, and in the event of an elongation that increases the operational risk, a warning signal could be generated or the machine could be shut down.

Claims

[1] Drive device (V), in particular a transport device of a container treatment plant (M), with at least one endless drive element (1) which can be driven to move and which is subject to elongation during operation, wherein readable section markings (9, 9') and a start marking (10) are provided on the drive element (1) distributed along the same, wherein a sensor (C) generating path increments (16) synchronously with the movement of the drive element (1) and at least one stationary marking reader (AB) generating passage signals (11, 12) are provided and are connected in a signal-transmitting manner to a computer unit (CU) which is designed to calculate the elongation either in sections (x, a - e, e') between the section markings (9) and / or in the drive element (1) based on computational processing of the path increments (16) and the passage signals (11, 12), characterized bythat the start marking (10) is formed by one of two section markings (9, 9') provided one behind the other at a short distance in the direction of movement (24) of the drive element (1), and that a common marking reader (AB) is provided for the section markings (9, 9') and the start marking (10). [2] Drive device according to claim 1, characterized by that with the computer unit (CU) in a path increment-related position and / or path distance determination of at least one point (7) of the drive element (1) an elongation can be computationally compensated at least within a path section traversed during the movement of the drive element (1). [3] Drive device according to claim 1, characterized bythat the drive element (1) is a link chain (17), preferably an endless link chain (17) drivable via a pull shaft (2) with connecting bolts (20) between link plates (18, 19), and that the encoder (G) generating the path increments (16), preferably a rotary encoder, is installed on the pull shaft (2). [4] Drive device according to claim 3, characterized by that the section markings (9, 9') and the start marking (10) are readable parts (21) of the link chain (17) itself and / or projections and / or bores and / or permanent magnets and / or RFID links and / or color marks on the link chain that can be distinguished from one another. [5] Drive device according to claim 3, characterized bythat in the link chain (17) the respective section marking (9, 9') and / or the start marking (10) is / are identifiably defined by a chain part (18, 19, 20) which is different from other, mutually similar chain parts (18, 19, 20), preferably by an iron chain link or magnetic chain link of a stainless steel link chain, or by a magnetic connecting bolt or a magnetic link plate compared to non-magnetic connecting bolts or link plates. [6] Drive device according to claim 1, characterized by that the start marking (10) is detectable as a section marking (9, 9') of a section different from the other sections of the drive element (1) divided into sections, preferably a section different in length from the other sections. [7] Drive device according to at least one of the preceding claims, characterized bythat a service area (22) with access to the drive element (1) and / or at least one section (x, a - e, e') positioned in the service area (22) is provided on the drive device (V). [8] Drive device according to at least one of the preceding claims, characterized by that the sections (a - e) between the section markings (9) are approximately of equal length, and that, preferably, the distance (x) of the start marking (10) from an adjacent section marking (9) seen in the direction of movement (24) is shorter than the distance between the section markings (9) of this section (a - e). [9] Method for determining an operational elongation of an endless drive element (1) of a drive device (V), in particular a transport device in a container treatment plant (M), wherein a computer unit (CU) during operation of the drive device (V) during the movement of the drive element (1) is transmitted equal path increments (16) of a sensor (C) synchronized with the drive element (1), upon passage of several section markings (9, 9') provided on the drive element (1) and dividing it into sections (x, a - e, e') and a start marking (10) provided on the drive element (1), passage signals (11, 12) are generated by at least one stationary marking reader (AB) and transmitted to the computer unit (CU), an elongation is calculated by the computer unit (CU) based on the path increments (16) and the through signals (11, 12), characterized by that the passage signals (11,12) from the section markings (9, 9') and the start marking (10) are generated by a common marking reader (AB). [10] Method according to claim 9, characterized bythat the computer unit (CU) uses the path increments (16) to determine the position and / or distance of at least one selected point of the drive element (1) and within a distance traveled during the movement of the drive element, preferably with reference to at least one reference position (7), and that a determined elongation is computationally compensated during the position and / or distance determination. [11] Method according to claim 9, characterized by that in each section (x, a - e, e') their individual elongation is determined permanently and / or periodically either automatically and / or operator-guided and the position of each section in the drive element (1) in relation to the start marking (10) is determined, and that in the position and / or distance determination the individual elongation of the respective section is individually compensated by calculation. [12] Method according to at least one of claims 9 to 11, characterized bythat when a predetermined extent of the determined individual elongation of a section (x, a - e, e') is reached, this section is moved to a service area (22) of the drive device (V) and the drive element (1) is stopped. [13] Method according to at least one of claims 9 to 11, characterized by that when a predetermined determined elongation of the drive element (1) and / or a section (x, a - e, e') is reached, an alarm signal is generated and / or the operation of the drive device (V) is / are stopped. [14] Method according to at least one of claims 9 to 13, characterized by that the drive element (1) drives a container transport device (5) of an inspection or washing machine of a container treatment plant (M), and that each transported container (6) is tracked with precise position via the computer unit (CU) by computationally compensating the determined elongation on the basis of the path increments (16).

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