Belt conveyor having a sliding bed with optimised coefficient of friction

Abstract

The invention relates to a belt conveyor (10) having a direction-specifically optimised coefficient of friction, which comprises: a sliding bed (20) with a support surface (34); and a belt (32), which, in contact with the support surface (34), is moved in a sliding manner over the support surface (34) in the conveying direction (23), while an item (32) resting on an outer side (42) of the belt (32) is transported downstream in a conveying direction (23); wherein a surface of the support surface (34) and / or an inner side of the belt (32) has a topography (44) with an increased coefficient of friction in a preferred direction (46), which is different from the conveying direction (23).

Description

Belt conveyor with friction-optimized sliding bed

[0001] Belt conveyors (also known in technical terms as conveyor belts, belt conveyors, or belt conveyors) are typically stationary conveyor systems that belong to the category of continuous conveyors. In the following, no distinction is made between the terms "belt" and "belt," or "belt conveyor" and "belt conveyor," as these terms are equivalent.

[0002] Belt conveyors have been used in industrial conveying and transport tasks for decades. Belt conveyors offer a very high level of operational reliability and have proven themselves in many applications. Belt conveyors are reliable transport systems that operate economically, productively, and environmentally friendly due to their low energy consumption (source: Wikipedia on "conveyor belt").

[0003] Belt conveyors can transport piece goods of various sizes, from the smallest dimensions to large-scale goods, over long distances. In addition, belt conveyors are capable of conveying piece goods horizontally as well as uphill or downhill. Further advantages arise from the supporting and therefore gentle type of movement. The conveyed goods move at rest on the belt. The widespread use in all areas of industry is also due to the lower investment cost compared to other piece goods conveyors such as driven roller conveyors, etc. A variety of belt types and materials for a wide range of applications enables the solution of almost all transport problems. There are basically two designs for (load-)bearing belt conveyor frames: frames with support rollers TR and frames with a slider bed GB, see Fig.10A and 10B (Source: "Handbook of Material Flow Technology - Unit Load Conveyors" by Norbert Axmann, ISBN 3-8169-2198-1). The present disclosure relates to belt conveyors with sliding beds.

[0004] Adverse factors are friction and wear. Sliding or wear movements occur between the underside of a belt and the supporting element, often a sliding plate construction or a sliding bed. Since there is a very close relationship between friction and wear behavior, the influencing factors can only be assigned to both processes simultaneously. The most important influencing factors are: material combination; surface quality (roughness, hardness, etc.); surface design; intermediate media (lubricant, compressed air, etc.); surface pressure; sliding speed; and temperature. These factors act simultaneously and are interdependent, so that a change in friction behavior cannot simply be attributed to just one of these factors, and a change in one of the factors can also influence others.During operation, belt conveyors experience sliding friction and during start-up, static friction. The laws of Amontons and Coulomb are used to describe the frictional processes. They specify a proportional dependence of the friction force FR on the normal force FN. The proportionality factor p is the coefficient of friction: p = F. R / FN.

[0005] To improve the friction behavior, i.e. to reduce the coefficient of friction, numerous material combinations have already been investigated and tested. Attempts to introduce air into the area between the belt and the slider bed have been made, for example, by using corrugated plates for the slider bed. Furthermore, it has already been proposed to provide the slider bed with macroscopic grooves running lengthwise to create air channels beneath the belt. However, the groove edges represent sharp (knife) edges, resulting in increased wear, especially when piece goods are fed horizontally at an angle onto the belt conveyor.

[0006] The undesirable offset of the belt relative to the slider bed is reduced or eliminated by the use of additional components. In an inclined belt conveyor, the belt's downstream sliding when the belt conveyor is stopped is prevented by appropriate braking devices. When unit loads are fed laterally onto the centrally located belt conveyor, side guides are provided at the edge of the slider bed or projections on the underside of the belt, which engage positively with corresponding recesses in the slider bed. This leads to the disadvantages mentioned above.

[0007] Further prior art can be found in the documents: US 2004 / 0201 160 A1; DE 20 2007 014 761 U1 ; JP H03- 259 810 A; DE 102011 011 734 B4; DE 102009 058 098 A1; DD 1 59628 A1; and DE 102014220425 A1.

[0008] It is therefore an object of the present disclosure to provide an improved belt conveyor.

[0009] This object is achieved by a belt conveyor with a direction-dependent optimized coefficient of friction, comprising: a sliding bed with a support surface; and a belt which, in contact with the support surface, is moved along the conveying direction in a sliding manner over the support surface while a piece of goods resting on an outer side of the belt is transported downstream in a conveying direction; wherein a surface of the support surface and / or an inner side of the belt has a topography with an increased coefficient of friction (between the materials of the upper side and the inner side), preferably exclusively in a preferred direction which differs from the conveying direction.

[0010] The topography of the contacting surfaces of the support surface and the belt is adjusted directionally (artificially through machining) by setting the friction coefficient (between the corresponding material pairing) higher in a preselected direction than in another direction, preferably the conveying direction. In other words, this means that the belt simply slides over the support surface in the conveying direction, whereas if the belt moves in an undesirable direction, greater resistance arises between the contacting surfaces due to a higher friction coefficient.

[0011] In the case of an inclined belt conveyor, braking devices are thus unnecessary because the belt cannot slip upstream. The same applies to a downward-sloping belt conveyor.

[0012] In the case of a feed conveyor system, a lateral guide can be dispensed with because the belt of the receiving belt conveyor is deflected less or not at all in the feed direction (of the feed conveyor) by the feeding of piece goods.

[0013] Preferably, the preferred direction (in a plan view) is oriented opposite, at an acute angle, or perpendicular to the conveying direction.

[0014] The preferred direction is oriented opposite to the conveying direction if the belt conveyor is an ascending belt conveyor.

[0015] The preferred direction is oriented at an acute angle or perpendicular to the conveying direction if the belt conveyor is used in a feed conveyor system where the feed conveyors are connected to the centrally arranged belt conveyor either at an acute angle (viewed in the conveying direction) or perpendicularly.

[0016] In particular, the topography is produced (mechanically) by the direct laser interference structuring process.

[0017] The direct laser interference structuring process is characterized by the ability to selectively ablate material with very high resolution (micrometer range and below) using laser interference. This process is ideally suited for modifying the surface texture, i.e., the topography, in a directionally dependent and predeterminable manner.

[0018] Preferably, the topography has a micropattern in the micrometer and submicrometer range, which in particular repeats periodically or is regularly structured.

[0019] Machining the surfaces in contact with each other at the micrometer level enables direction-dependent functionalization of the surfaces, i.e., direction-dependent friction coefficient optimization. This goes beyond the "normal" friction coefficient, which is direction-independent (and area-independent) on a macroscopic scale.

[0020] In particular, the micropattern is formed from a plurality of projections, which preferably have a predetermined profile shape (in side view).

[0021] The surface therefore has a predetermined texture, which a belt conveyor designer can specifically define in advance, particularly depending on the direction. The design is particularly application-specific.

[0022] Advantageously, the projections are arranged in rows. In particular, the rows are aligned perpendicular to the conveying direction.

[0023] The row-wise arrangement and the alignment of the rows increase the order of the projections and therefore result in the desired directional dependence of the optimized friction coefficient.

[0024] Preferably, the projections are tooth-shaped, wherein the projections each comprise in particular a first flank which rises less steeply in a conveying direction than a second flank, and the second flank which adjoins the first flank in the conveying direction.

[0025] This profile shape is particularly well-suited for inclined belt conveyors to prevent the belt from slipping upstream when the belt is stopped. This eliminates the need for brakes.

[0026] Alternatively, the projections may be pyramid-shaped, wherein the projections each preferably comprise a first flank which rises less steeply in the opposite direction to a feed direction than a second flank which is arranged in front of the first flank in the feed direction, and the second flank.

[0027] This profile shape is particularly suitable for infeed conveyor systems where the belt conveyor is centrally located and receives piece goods from one or more infeed conveyors. Lateral deflection of the belt is reduced or even eliminated when infeeding piece goods.

[0028] In particular, the topography is formed in a coating (layer).

[0029] The topography does not have to be created directly on the surface of the sliding bed or the inside of the belt, but can be formed in a separate layer that can have different material properties than the sliding bed or the belt.

[0030] The coating also allows for subsequent application of the topography to the slider bed and / or belt. The topography can be manufactured separately from the slider bed and / or belt. This means that the topography can be bonded to the slider bed and / or belt on-site, for example. This is particularly advantageous for retrofitting existing belt conveyors.

[0031] Preferably, the topography is integrated into the sliding bed. The sliding bed is often made of metal. Laser-based topography generation can be achieved well on metal surfaces (as well as polymer surfaces).

[0032] Metals are abrasion-resistant, so topographical contamination is less significant during the lifetime of the belt conveyor.

[0033] In particular, the topography is only provided in an area of ​​laterally arranged feed conveyors.

[0034] This means that the topography doesn't have to extend the entire length of the belt conveyor. The topography can be implemented in sections. This reduces the cost of the overall system. Topography is only implemented in areas where disruptive forces may occur.

[0035] Furthermore, it is preferred if the topography is (also) integrated into the band.

[0036] It is understood that the features of the invention mentioned above and those to be explained below can be used not only in the combination specified in each case, but also in other combinations or on their own, without departing from the scope of the invention.

[0037] Further features and advantages of the invention will become apparent from the following description of preferred embodiments with reference to the drawings. Fig. 1 is a block diagram of a belt conveyor; Fig. 2 is a side view of a belt conveyor according to Fig. 1; Fig. 3 a perspective detailed view of a topography; Fig. 4 is a schematic plan view (Fig. 4A) and side view (Fig. 4B) of the topography of Fig. 3; Fig. 5 is a perspective view of an ascending belt conveyor; Fig. 6 a perspective detailed view of another topography; Fig. 7 is a schematic plan view of the topography of Fig. 6; Fig. 8 is a plan view of a feed conveyor system; Fig. 9 is a side view of the topography of Fig. 6 along a line IX-IX in Fig. 7; and Fig. 10 a conventional belt conveyor machine frame with a sliding bed (Fig. 10A) and with support rollers (Fig. 10B).

[0038] Fig. 1 shows a block diagram of a belt conveyor 10. The belt conveyor 10 has: a (base) frame 12, a drive 14, a traction means 16, a deflection device 18 and a sliding bed 20. The belt conveyor 10 can further (optionally) comprise: a tensioning device 22 for tensioning the traction means 16 in a conveying direction 23 (cf. Fig. 2) and / or a guide device 24 for guiding the traction means 16 laterally, i.e. transversely or perpendicularly to the conveying direction 23.

[0039] The frame 12 can, for example, be formed by a plurality of (steel) profiles that are configured to accommodate and (directly) support the drive 14, the deflection device 18, and the sliding bed 20. The frame 12 supports the other components, such as the traction device 16, indirectly. The frame 12 is typically configured to be stationary on the floor, a platform, a suspended ceiling, etc. of an (intralogistics) system (distribution system, storage and order-picking system, production system, etc.) or to be suspended from a ceiling to form part of a conveyor system (not shown) that maps a material flow. However, the frame 12 can also stand on lockable rollers to reposition the belt conveyor 10 within the system by sliding it.

[0040] The drive 14 has a motor 26 and at least one roller 28, which is rotatably mounted in the frame 12. The motor 26 can be integrated into the roller 28. The drive 14 is configured to move the traction means 16 in the conveying direction 23, which can be reversible. The movement is continuous.

[0041] The traction means 16 represents a conveying means, on the outer side 42 of which one or more piece goods 30 are transported in the conveying direction 23 along a longitudinal direction X of the belt conveyor 10. The traction means 16 is a belt 32. In an assembled state (see side view of Fig. 2), the belt 32 is self-contained, allowing it to be moved continuously.

[0042] The belt 32 can be a multi-layer (plastic) fabric belt with a cover layer and intermediate layers, a (plastic) link chain belt, or similar. The belt 32 can be coated. The belt 32 can have (raised) knobs, cross cleats, corrugated edges, etc. on its outer side 42 for upward conveying to additionally hold the piece goods 30. The inner side 40 of the belt 32 should be as smooth as possible, i.e., have a low (sliding) friction coefficient to reduce friction losses during transport, i.e., when piece goods 30 are transported with the belt 32.

[0043] The deflection device 18 comprises at least two (deflection) rollers, which are arranged spaced apart in the longitudinal direction X at an upstream end and at a downstream end of the belt conveyor. Additional deflection rollers (not shown) could be arranged in between. Fig. 2 shows only two deflection rollers by way of example, of which the downstream deflection roller is implemented as the aforementioned drive roller 28. It is understood that the other deflection roller could also implement the drive roller 28 (or both).

[0044] The sliding bed 20 comprises at least one support plate 29, see Fig. 2. The sliding bed 20 defines a support surface 34. The support surface 34 can be implemented by an upper side 31 of the support plate 29 or by another surface arranged on top, which is formed, for example, by a coating on top of the support plate 29. The support plate 29 can be formed, for example, by: a sheet metal; a galvanized sheet metal; a powder-coated sheet metal (possibly with Teflon additives, with a hammer finish to achieve 3D effects, or similar); a black sheet metal; a stainless steel sheet metal; wood; plastic; metal; metal alloy; or a combination thereof.

[0045] The support surface 34 is arranged and configured to support the belt 32 in a loaded state by contact from below in order to bear the load (weight) of the piece goods 30, which, in a normal transport state of the conveyor 10, rest on top of an upper run 36 of the belt 32. The belt 32 has the upper run 36 and a lower run 38. In mechanical engineering, a run refers to a part or section of the (endlessly) rotating traction means 16 exerting a tensile force.

[0046] As shown in the schematic side view of Fig. 2, which illustrates an exemplary belt conveyor 10 according to Fig. 1, the support plate 29 - and thus the support surface 34 - is arranged (vertically in the height direction Y) between the upper run 36 and the lower run 38. The support surface 34 is aligned parallel to a (building) floor (not illustrated), i.e. horizontally, because the belt conveyor 10 is oriented horizontally by way of example. It is understood that the support surface 34 can also be aligned inclined relative to the floor if the belt conveyor 10 is used as an inclined conveyor (cf. Fig. 5) or a downward conveyor. However, the support surface 34 is always aligned substantially parallel to the upper run 36, apart from (unintentionally) sagging sections of the belt 32.

[0047] The support surface 34 is preferably arranged at a distance A from the upper run 36. The distance A is set so that the belt 32 can be moved as contactlessly as possible over the support surface 34 in unloaded sections, i.e. where none of the piece goods 30 is at rest, in order to minimize or eliminate the (sliding) friction. The distance A is usually in the order of 2-3 mm. Depending on its length (in the X direction) and belt tension, an underside of the upper run 36, i.e. the inner side 40 of the belt 32, can unintentionally sag partially vertically downwards when the belt 32 is unloaded (not shown in Fig. 2) and thus come into (undesired) contact with the support surface 34. The (optionally provided) tensioning device 22 of Fig. 1 is, among other things,also designed to (permanently) exert a force in the conveying direction 23 on the belt 32 in order to prevent sagging of the belt 32 (in the unloaded state) as far as possible and also to prevent spinning of the (drive) roller 28, e.g. when starting up.

[0048] The support surface 34 can be formed from one or more support plates 29, which are arranged one behind the other in the longitudinal direction X and / or next to one another in the transverse direction Z and form a (uniform) sliding base. Figure 2 shows an example of a (single) support plate 29 that defines the support surface 34. A single support plate 29 is less subject to wear because there are no abutting edges in the conveying direction 23. In Figure 2, the support plate 29 extends essentially along the entire length (X direction) of the upper run 36 between the deflection rollers.

[0049] The support surface 34 preferably defines (macroscopically viewed) a flat, level surface. The support surface 34 extends in the transverse direction Z (perpendicular to the plane of the drawing in Fig. 2) preferably over a (total) width of the belt 32 and possibly even beyond, in order to support the belt 32 from below even in the event of a lateral deflection (in the Z direction, i.e., perpendicular to the plane of the drawing in Fig. 2), as will be explained below for the case of a lateral feed of piece goods 30. However, the width of the belt 32 can also be smaller than a width of the support surface 34.

[0050] The guide device(s) 24 of Fig. 1 serve to guide the belt 32 in the conveying direction 23 and, if necessary, laterally (mechanically). Exemplary guide devices 24 are guide belts (not shown) attached to the inner side 40 of the belt, which extend in the conveying direction 23 and run in grooves (not shown) in the upper side 31 of the support plate 29, wherein the grooves in this case also extend in the conveying direction 23. Alternatively or additionally, clamp-like lateral guides (not shown) can be provided laterally to the edge of the belt 32, which are attached to the frame 12 in order to keep the belt 32 aligned in the transverse direction Z. Alternatively, the belt 32 can be raised on its inner side 40 in the outer edge region in order to grip around the slide bed 12 for lateral guidance in the transverse direction Z (not shown).

[0051] The sliding bed 20 or the support surface 34 (i.e., a sliding base) must be aligned as precisely as possible relative to the rotating belt 32, since they guide the belt 32 very closely due to sliding friction and cause wear through abrasion. The edges of the sliding base should be rounded.

[0052] Sheet steel, hard plastics (Resopal, Duropal, etc.), (glued) plywood panels, etc., are generally used as support surface materials, as already explained above for the support plate 29. These materials, together with the smooth (running) inner surface 40 of the belt 32, result in favorable friction behavior, which is determined by the coefficient of friction of the contacting material pair. Depending on the (macroscopic) surface quality and operating conditions, variations in the corresponding coefficient of friction are generally possible.

[0053] According to the present disclosure, the support surface 34 and / or the inner side 40 of the belt 32, which come into contact with one another during transport, have a special topography 44 comprising a micropattern in the micrometer and submicrometer range, which is machined to result in a direction-dependent friction coefficient optimization, as will be explained in more detail below. The micropattern differs (in the micrometer range and below) from a naturally occurring surface, which is chaotically structured on this scale, by an arrangement (pattern) that is expressed in a regular structure (texture), e.g., a periodically repeating one, as will also be explained in more detail below.

[0054] Direction-dependent friction coefficient optimization is understood to mean an optimization of the contacting surfaces such that the friction coefficient in a selected direction (preferred direction) is higher than in (all) other directions, in particular in the normal conveying direction 23.

[0055] The topography 44 generally describes a surface texture and is formed by a plurality of projections or elevations 48 (see, for example, Figs. 3 and 4). The topography 44 describes both a geometric shape and physical and / or chemical properties of technically used, mutually rubbing surfaces, which in the present disclosure are embodied as functional microstructures or micropatterns. The topography 44 thus describes the regular (2D and 3D) structure of surfaces in the micrometer and submicrometer range.

[0056] Surfaces with deterministic topographies 44 exhibit superior surface properties compared to conventional (natural) surfaces with random roughness. Roughness describes the unevenness of a surface height. Surface roughness can be modified conventionally, for example, by polishing, rolling, grinding, pickling, sandblasting, etching, vapor deposition, or corrosion.

[0057] In the present disclosure, the topography 44 is used to functionalize the surfaces that rub against each other by micro- and / or nanostructuring at least one of these surfaces. The corresponding functional microstructure, i.e. the topography 44, is obtained by machining an ordinary surface by specifically removing material through heating. In the present disclosure, in particular, a method for direct laser interference structuring is used, which is described, among other things, in DE 10 2011 011 734 B4. Direct laser interference structuring is applicable, for example, to metal, polymer and ceramic surfaces, as used in the field of belt conveyors 10. Machining the surface to produce the structure shown below or the corresponding micropattern is not possible.

[0058] Fig. 3 shows a perspective detailed view obliquely from above of a first exemplary topography 44-1, as used, for example, in an ascending belt conveyor 10' illustrated in Fig. 5. Fig. 4A shows a schematic top view and Fig. 4B a schematic side view of the topography 44-1 of Fig. 3.

[0059] Fig. 5 schematically illustrates a belt conveyor 10 according to Fig. 1 as an ascending belt conveyor 10', which rises at an angle α relative to the horizontal H. The piece goods 30 resting on the belt 32 are thus transported vertically upwards (in the Y direction) and simultaneously horizontally forwards (in the X direction) along the conveying direction 23. During transport, the opposing surfaces of the sliding bed 20 (support plate 29) and the belt 32 (inner side 40, see Fig. 2) touch each other. One or both surfaces have a topography 44. For the sake of simplicity, it is assumed below that the sliding surface 34, which is defined by the upper side of the sliding bed 20, has the topography 44-1.

[0060] The topography 44-1 of Figs. 3 and 4 causes a friction coefficient 1 in the conveying direction 23 to be smaller than a friction coefficient 2 in the preferred direction 46. The preferred direction 46 is generally selected depending on the application. In the present example of the ascending conveyor 10' in Fig. 5, the preferred direction 46 is oriented opposite to the conveying direction 23. The friction coefficient is therefore increased in the preferred direction 46 in this application. In this way, the belt 32 is braked should the belt 32 move downstream, which is undesirable. In a case where the belt 32 is stopped, for example, while the piece goods 30 are being transported upwards upstream, slipping of the belt 32 against the conveying direction 23 is inhibited and ideally prevented. In this way, the ascending belt conveyor 10' does not need to have a brake, thus saving costs and maintenance work. The band 32 can be held solely by (adhesive) friction.Nevertheless, the running properties of the belt 32 in the conveying direction 23 are good.

[0061] The topography 44-1, which causes the above-mentioned effects, is illustrated in detail in Figs. 3 and 4. The scale of 3 pm shown in Fig. 3 represents the actual size ratios of the projections 48. The topography 44-1 has a plurality of projections 48. The projections 48 protrude (microscopically) in the height direction Y from the material M (cf. Fig. 4B) of the otherwise (macroscopically) flat sliding surface 34 (directed).

[0062] The projections 48 in Figures 3 and 4, for example, are tooth-shaped. In the side view of Figure 4B, the corresponding tooth shape has a first flank 50 which rises gently at an angle ß in the conveying direction 23 and then a second flank 52 which finally falls more steeply at an angle θ. The approach angle β should be selected to be as flat as possible, i.e. less than 90°, in order to produce minimal resistance during a (relative) movement of the piece goods 30 in the conveying direction 23, whereas the return angle θ is preferably selected to be greater than the approach angle β in order to generate an increased retaining force during a movement counter to the conveying direction 23. Two of the tooth-shaped projections 48-1 and 48-2 are shown as examples in Figure 4B.

[0063] The tooth-shaped projections 48 can be shaped like a shark fin, so that a tip of each projection 48 is slightly rounded and has a plateau, see Fig. 4B. In Fig. 4B, the second flank 52 is oriented perpendicular to the plane of the sliding bed 20. It is understood that the second flank 52 can also be more inclined in order to enclose an obtuse angle 0 with the horizontal H. In this case, the projections 48 function like barbs and can hook into the (rough) topography of the belt 32 if the belt 32 unintentionally moves backwards, i.e. against the conveying direction 23.

[0064] The projections 48 are preferably arranged in rows 54. In the section of Fig. 3, two rows 54-1 and 54-2 are shown, each aligned along the transverse direction Z, i.e., perpendicular to the conveying direction 23. The rows 54 are arranged in the longitudinal direction X, i.e., parallel to the conveying direction 23, at a (row) spacing 56. In Fig. 3, seven to eight projections 48 per row 54 are shown as examples. The projections 48 of each of the rows 54 are preferably arranged spaced apart from one another in the transverse direction Z, cf. tooth spacing 58 in Fig. 4A.

[0065] Each of the teeth in Fig. 3 is approximately 8-9 pm long, less than 1 pm wide, and approximately 3 pm high. The tooth spacing 58 is approximately 2 pm.

[0066] It is understood that each of the rows 54 may also be formed by a single projection 48 (continuous in the Z direction).

[0067] Figure 6 shows a perspective detailed view of a second exemplary topography 44-2 viewed from almost vertically above. Figure 6 shows a realistic size scale of 30 pm. The projections 48 are pyramid-shaped. The projections 48 have a triangular or quadrangular base, and their tips protrude from the (macroscopically flat) sliding surface 34.

[0068] A micropattern corresponding to the arrangement of Fig. 6 is schematically illustrated in a plan view of Fig. 7. The projections 48 are again arranged in a regular pattern. The pattern of Fig. 7 is again defined by rows 54 of projections 48. The rows 54 extend along the transverse direction Z. The rows 54 are aligned in Fig. 7 along the transverse direction Z and in the longitudinal direction X, ie in the conveying direction 23, spaced from each other. The rows 54 of Fig. 7 are preferably arranged overlapping in the longitudinal direction X.

[0069] The topography 44-2 is preferably used for the lateral feeding (infeeding) of piece goods 30 onto a belt conveyor 10, as schematically illustrated in Fig. 8. Fig. 8 shows a plan view of the belt conveyor 10, which is preferably oriented horizontally and which is loaded laterally with piece goods 30, for example, by feed or infeed conveyors.

[0070] The feed conveyors 60-1 and 60-2 move the piece goods 30 (due to their orientation) perpendicularly onto the centrally arranged belt conveyor 10. The first feed direction 62 is thus oriented parallel to the Z direction and perpendicular to the conveying direction 23. It is understood that more or less vertically arranged feed conveyors 60 can be provided, even on different sides of the central belt conveyor 10.

[0071] Furthermore, obliquely oriented feed conveyors 60 can be provided, see feed conveyors 60-3 and 60-4, which adjoin the belt conveyor 10 at an acute angle and define a second feed direction 64.

[0072] 3 to 5, it is again assumed that the support surface 34 is integrated into the sliding bed 20 by way of example, even if, alternatively or additionally, the inner side 40 of the belt 32 could be correspondingly microstructured. Furthermore, it is understood that the surface of the sliding bed 20 does not have to be completely microstructured. This means that the support surface 34 does not have to be provided over the entire surface. In the example of the feed according to Fig. 8, it is recommended that the microstructuring preferably only be provided in sections, i.e. in the immediate area 66 of the feed, which is indicated by dashed lines in Fig. 8. The area 66 does not have to extend over the entire width of the conveyor 10 (not illustrated). It is sufficient to select the area immediately adjacent to the lateral feed.In these areas 66 there is a risk that the supplied piece goods 30 transmits a force transverse to the conveying direction 23 to the belt 32, which results in the belt 32 being moved laterally. in the transverse direction Z. This transverse offset can lead to running disturbances and damage, which must be avoided.

[0073] The above statements regarding the angles ß and θ in Figs. 3 and 4 apply analogously to the application of the lateral feed, which is illustrated by way of example in Fig. 8, wherein an orientation of the preferred direction 46 is to be adjusted accordingly and the orientation of the conveying direction 23 is maintained. The projections 48 are to be designed such that they prevent the belt 32 from being deflected in the feed direction while the piece goods 30 are moved onto the belt 32 in the feed direction.

[0074] Fig. 9 shows a side view of the micropattern of Fig. 7 along a line IX-IX in Fig. 7. The conveying direction 32 in Fig. 9 points perpendicularly into the plane of the drawing.

[0075] The projections 48 are arranged such that an increased coefficient of friction p2 is established opposite to the respective feed direction 62 or 64. It is understood that the coefficient of friction p2 is influenced by the surface structuring in a direction-dependent manner according to the respective feed direction 62 or 64. The rows 54 are oriented in the regions 66 depending on the respective feed direction 62 or 64. In the region of the feed conveyors 60-3 and 60-4, the rows 54 are arranged (in a plan view) at an acute angle to the conveying direction 23 in order to define a right angle with the second feed direction 64.

[0076] Fig. 9 further illustrates that the projections 48 can be formed with different heights along the transverse direction Z in the Y direction in order to effect an automatic resetting of the belt 32 after an (unintentional) lateral deflection of the belt 32 caused by the introduction.

[0077] It is understood that the micropattern according to Figs. 3 and 4 and the micropattern according to Figs. 6 and 8 (or also according to Fig. 9) can be superimposed to achieve both effects (anti-slip and lateral fixation) simultaneously. A resulting micropattern can be used when piece goods 30 are fed laterally onto an inclined belt conveyor (not illustrated).

[0078] Furthermore, it is possible to align the micropattern in such a way that a restoring force is generated in the lateral edge regions of the band 32, which, in the event of a lateral deflection outwards, moves the band 32 back to the center of the band 32 in the Z direction.

[0079] It is clear that the materials of the surfaces in contact with each other (support surface 34 and inner side 40 of the circulating belt 32) should be selected to be as abrasion-resistant as possible to prevent wear of the topography 44 due to abrasion. If the sliding surface is realized by a coating, the coating must be sufficiently thick. Preferably, the coating is designed as an adhesive film that can be applied (subsequently) to the sliding bed 20 and / or the inner side 40 of the belt 32.

[0080] Furthermore, it is understood that, in addition to the tooth and pyramid shapes discussed above, other (cross-sectional) shapes are possible for the projections 48. What is important in this context is the direction-specific optimization of the coefficient of friction, which is increased or decreased in a first direction and lower or higher in an opposite direction.

[0081] The arrangement of the projections 48 is also variable. Row arrangements were discussed in more detail above. However, it is possible to group differently arranged projections 48 that achieve the same functionalization of the (material) surface. List of reference symbols: 10 belt conveyors 12 (Basic) frame 14 Drive 16 traction devices 18 Deflection device 20 sliding bed 22 clamping device 23 Conveying direction 24 guidance device 26 Engine 28 (Drive) roller 29 Support plate 30 general cargo 31 top of 29 32 volumes 34 Support surface 36 Upper Drum 38 Lower strand 40 inside of 32 42 outside of 32 44 Topography 46 Preferred direction 48 projection or elevation50 1st flank 52 2nd flank 54 row 56 (row) spacing 58 tooth pitch 60 feed conveyors 62 1. Feed direction 64 2. Feed direction 66 Feeding area

Claims

A belt conveyor (10) with a direction-specifically optimized coefficient of friction, comprising: a sliding bed (20) with a support surface (34); and a belt (32) which, in contact with the support surface (34), is moved in a sliding manner along the conveying direction (23) over the support surface (34) while a piece of goods (30) resting on an outer side (42) of the belt (32) is transported downstream in a conveying direction (23); wherein a surface of the support surface (34) and / or an inner side of the belt (32) has a topography (44) with an increased coefficient of friction in a preferred direction (46) that differs from the conveying direction (23). Belt conveyor (10) according to claim 1, wherein the preferred direction is oriented opposite, at an acute angle, obliquely, or perpendicular to the conveying direction (23). Belt conveyor (10) according to claim 1 or 2, wherein the topography (44) is produced by the direct laser interference structuring process.The belt conveyor (10) according to any one of claims 1 to 3, wherein the topography (44) has a micropattern in the micrometer and submicrometer range. The belt conveyor (10) according to claim 4, wherein the micropattern is formed from a plurality of projections (48). The belt conveyor (10) according to claim 5, wherein the projections (48) are arranged in rows (54). The belt conveyor (10) according to claim 6, wherein the rows (54) are aligned perpendicular to the conveying direction (23). Belt conveyor (10) according to one of claims 5 to 7, wherein the projections (48) are tooth-shaped, and wherein the projections (48) each preferably comprise a first flank (50) which rises less steeply in the conveying direction (23) than a second flank (52), and the second flank (52) which adjoins the first flank (50) in the conveying direction (23). Belt conveyor (10) according to one of claims 5 to 7, wherein the projections (48) are pyramid-shaped, and wherein the projections (48) each preferably comprise a first flank (50) which rises opposite to a feed direction (62, 64) less steeply than a second flank (52) which is arranged upstream of the first flank (50) in the feed direction (62, 64), and the second flank (52). Belt conveyor (10) according to one of claims 1 to 9, wherein the topography (44) is formed in a coating.Belt conveyor (10) according to one of claims 1 to 10, wherein the topography (44) is integrated into the sliding bed (20). Belt conveyor (10) according to claim 11, wherein the topography (44) is provided only in a region (66) of laterally arranged feed conveyors (60). Belt conveyor (10) according to one of claims 1 to 11, wherein the topography (44) is integrated into the belt (32).

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