SCRAPER WITH EASILY INTERCHANGEABLE SCRAPING ELEMENT

Abstract

A scraper 18 for a conveyor belt 12, a scraper module 26, 126 for the same, a conveyor belt 10 with the present, and a method for exchanging a scraping element 42 in a scraper 18 or conveyor belt 10 are described. The scraper 18 according to the invention includes a system carrier 24 with at least one scraper module 26, 126. The scraper module 26, 126 has a base element 32 accommodated in the system carrier 24 and a scraping element 42 for abutting the conveyor belt 12. In order to make it possible to change the scraping element 42 particularly easily, the scraping element 42 is rotatably attached with a rotary coupling about a rotation axis 64 with respect to the base element 32.The rotational coupling is configured so that, in a rotational position of the scraping element 42 within a fixed angular range 68b, the scraping element 42 is firmly coupled to the base element 32 in the direction of the rotation axis 64. In a rotational position of the scraping element 42 within a release angular range 68a, the scraping element 42 can be separated from the base element 32 in the direction of the rotation axis 64.

Description

SCRAPER WITH EASILY INTERCHANGEABLE SCRAPING ELEMENT FIELD OF INVENTION The invention relates to a scraper for a conveyor belt, a scraper module for the same, a conveyor belt equipped with the same, and a method for exchanging a scraper element. BACKGROUND OF THE INVENTION The use of scrapers is common on conveyor belts used to transport a wide variety of goods. By placing a scraper against the moving conveyor belt, any transported goods adhering to it are scraped off. Known scraper systems have a system carrier aligned transversely to the direction of travel of the conveyor belt, on which a plurality of scraper modules with scraper elements are located. DE 10 2013 006 821 A1 describes a belt scraper system consisting of modules for the return region of conveyor belts. A system carrier is positioned transversely to the direction of operation of the conveyor belt. Multiple scraper modules are attached side by side to the system carrier. Each scraper module carries a scraper blade that contacts the belt in a detachable manner. WO 95 / 19310 describes a device for scraping contaminants from conveyor belts in conveyor systems. A system carrier is attached to a bearing frame system carrier for the conveyor belt. A scraping element, having a scraper blade attached to a blade holder, is arranged so that it abuts the conveyor belt in the operating position in a detachable manner. The scraping element has a torsion spring joint, in which the blade holder is guided in a pivoting and spring-loaded manner around a horizontal pivot axis so that when it encounters obstacles that adhere firmly to the conveyor belt, it can pivot away and then pivot back to the operating position.The blade holder is pivotally mounted by means of a swivel bearing with a limited rotation angle so that the scraper blade that touches the belt mesh can be adapted to the contour of the belt mesh through automatic rotation. The scraping elements that come into contact with the conveyor belt during operation are subject to considerable wear and must be changed and replaced regularly. The objective is to propose a scraper, a scraper module for it, a conveyor belt with the scraper, and a method for exchanging a scraping element within the scraper, thus enabling simple scraping element replacement. The objective is achieved by means of a scraper according to claim 1, a scraper module therefor according to claim 13, a belt conveyor according to claim 14 and a method according to claim 15. The dependent claims relate to convenient embodiments of the invention. BRIEF DESCRIPTION OF THE INVENTION The scraper according to the invention has at least one scraper module, preferably multiple scraper modules, on a system carrier. Each scraper module includes at least one base element accommodated on the system carrier and a scraping element provided to contact the conveyor belt. The scraping element can be, for example, a scraping block made of a flexible material, particularly if the scraper is provided as a pre-scraper, i.e., for arrangement in the region of a deflection of the conveyor belt. The scraper can preferably be accommodated in the return region of the conveyor belt. The scraping element most preferably has a scraping edge, particularly preferably made of metal, for example, carbide. The scraping element can be detachably abutted against the conveyor belt. The base element of the scraper module can be attached to the system carrier in various ways and, preferably, can be detached. It is preferably mounted to the system carrier by means of a retaining clamping device. According to the invention, the scraping element is attached to the base element by means of a rotary coupling so that it can be rotated around a rotation axis. The rotary coupling is configured so that, depending on the rotational position of the scraping element with respect to the rotation axis, a different coupling results: in the case of a rotational position within an angular range, referred to herein as the fixed angular range, the scraping element—with respect to movement in the direction of the rotation axis—is firmly coupled to the rest of the scraper module, i.e., in particular the base element; whereas, in a rotational position within an angular range, referred to herein as the release angular range, in the direction of the rotation axis, it can be separated from the rest of the scraper module, i.e., in particular the base element. The rotational coupling then ensures a capacity of rotation of the scraping element around the axis of rotation so that alignment with respect to the belt surface is possible and, therefore, during operation, the scraping element has good contact with the conveyor belt and can follow, for example, slightly loosely, the shape of the conveyor belt. The rotary coupling also guarantees, within the fixed angular range, a fixed coupling in terms of longitudinal movement in the direction of the rotation axis. That is, in a rotational position within the fixed angular range, the scraping element can indeed be rotated, but it cannot be separated from the base element. During a rotation of the scraping element such that it assumes a rotational position within the release angular range, the rotary coupling, in contrast, releases the scraping element so that it can be separated—preferably removed, for example, for servicing purposes—in the direction of the rotation axis. The fixed angular range and the preferred release angular range can be selected such that the scraping element, during operation (i.e., with the scraping element in contact with the conveyor belt), is constantly within the fixed angular range, and there is a sufficient distance from the release angular range so that the latter is not reached with sufficient certainty during operation. In other words, rotation of the scraping element within the release angular range is prevented by contact with the conveyor belt. The fixed angular range, for example, can be selected such that a horizontal alignment of the scraping element or an alignment of the scraping element parallel to the system carrier lies within the fixed angular range, preferably at least substantially centrally.This position can be assumed to be the mid-position, where the fixed angular range extends, starting from the mid-position, preferably at least over + / - 30°, more preferably at least over + / - 40°, and particularly preferably at least over + / - 60°. Therefore, the release angular range, particularly preferably, only begins at the tightest twist around the axis of rotation, for example, 90° + / - 20°, so that a firm engagement is consistently guaranteed in all normally expected operating positions. Furthermore, the scraping element can be easily separated from the base element, and therefore from the system carrier, for maintenance purposes simply by rotating it around the axis of rotation far enough to reach the angular release range. The scraping element can then be removed along the axis of rotation without having to disconnect any additional connections. The result is a scraper with an easily interchangeable scraping element, achieved through a very simple design. The ability to rotate around the axis of rotation serves two purposes: first, to align the scraping element during operation, and second, to detach the scraping element if it needs to be replaced. The scraping element can preferably be rotated manually without tools. To change, i.e., replace, for example, a worn scraping element with a new one, it is sufficient to rotate the old scraping element within its release angle (for which reason it might be necessary beforehand to move the system carrier to a position where the scraping element is far enough from the conveyor belt to allow rotation). The scraping element can then be separated from the base element, and a new scraping element, positioned within its release angle, can be attached to, or inserted into, the base element. This new scraping element can then be rotated to a fixed locking angle within its rotational range. The rotational coupling can be obtained in different ways to fulfill the function according to the invention. According to a preferred embodiment, it has a coupling element and an insertion opening for the same, configured so that the coupling element can be guided through the insertion opening in a first rotational position within the release angular range, and the coupling element can be secured to the insertion opening in a second rotational position within a fixed angular range. The insertion opening and its flange can be part of the base element or attached to it, and the coupling element can be provided on the scraping side or vice versa. The coupling element, preferably, can be accommodated on a shaft that can be inserted into an insertion sleeve, wherein the insertion opening is formed within the insertion sleeve. A flange of the insertion opening can be configured to project inward into the insertion sleeve. The preferred shaft is connected to the scraping element, for example, firmly and immovably attached to it, while the insertion sleeve is fixed to the base element. The rotational capability of the scraping element is ensured by the rotational capability of the shaft within the insertion sleeve. Preferably, the shaft and / or the insertion sleeve, and particularly preferably also the axis of rotation, can extend at least substantially perpendicular to a scraping edge of the scraping element, or at least at an angle θ of more than 45°, preferably 60° or greater. The axis of rotation is also preferably positioned at least substantially perpendicular to the system carrier, or at least at an angle γ of more than 60°. Therefore, viewed from above or below, the axis of rotation is preferably at least substantially parallel to the direction of travel of the conveyor belt. Viewed from the side, i.e., horizontally and transversely to the direction of travel of the conveyor belt, the axis of rotation may enclose a relatively small angle γ of, for example, 0.35° with the direction of travel of the conveyor belt, in preferred embodiments. However, alternative convenient embodiments are also possible, in which the axis of rotation is positioned considerably more gradually with respect to the direction of travel of the conveyor belt, i.e., at larger angles γ. According to a preferred embodiment, the rotation of the scraping element around the axis of rotation is slightly damped or deliberately delayed, so that no free rotation occurs under the influence of, for example, only gravitational forces acting on the scraping element. In contrast, the rotational engagement is so smooth that, under the influence of forces arising from the contact of the scraping element with the conveyor belt, free rotation and alignment of the scraping element is possible. Due to the targeted damping or slowing, the installation of the scraping element is simplified because it is then possible to predefine a desired alignment of the scraping element, for example, by manual rotation, without undesirable alteration.In the case of the preferred configuration of the rotary coupling having a shaft that can be inserted into an insertion sleeve, damping can be effected, for example, by means of a friction element that is provided to contact the shaft and / or an inside of the insertion sleeve to dampen relative movement, in particular rotation, between the shaft and the insertion sleeve. Furthermore, in the preferred configuration of the rotary coupling with a shaft and an insert sleeve, a sealing element can be provided to seal between the shaft and the inside of the insert sleeve to prevent the ingress of contaminants. The sealing element can preferably encompass the entire shaft, for example, as a Tonca gasket. In particular, the sealing element can also be used to achieve the desired damping of relative movement between the shaft and the insert sleeve. According to a further development of the invention, the scraper module may have a joint by means of which the scraping element can be pivoted with respect to the system carrier. A pivot axis of the joint may preferably be aligned at least substantially parallel to the system carrier. It is further preferred that a pivot axis of the joint be aligned at least substantially perpendicular to the axis of rotation of the rotary coupling, or at least at an angle of at least 60° to it. By pivoting the scraping element on the joint, variable contact with the conveyor belt can preferably be achieved; in particular, the possibility of pivoting the scraping element away from the belt surface by means of a pivoting movement on the joint is preferred, to allow obstacles to be bypassed. A spring element can be provided to apply a pressing force to the scraper element in the direction of the conveyor belt. This ensures resilient contact between the scraper element and the conveyor belt. Any type of spring element, such as a torsion spring, coil spring, tension spring, or compression spring, can be used for this purpose. A rubber torsion spring, preferably housed within the seal, is particularly preferred. According to a convenient arrangement, a stop is provided for the pivoting movement of the scraping element at the joint. As a result, the movement of the scraping element in the direction of the conveyor belt can be limited. Preferably, the stop is positioned so that, even in the stopped position, there is still some deviation in the direction of the conveyor belt surface. The preferred scraping element can be connected via a scraper arm to the joint, where the rotary coupling is formed on the scraper arm. The scraper module according to the invention of claim 13 is provided as part of the described scraper and includes at least the base element, the scraping element, and the rotation coupling. When the scraper is deployed on a belt conveyor according to the invention of claim 14, the system carrier is aligned transversely to the conveyor belt and the scraping element, or preferably a plurality of scraping elements, come into contact with the conveyor belt. BRIEF DESCRIPTION OF THE FIGURES The embodiments of the invention are described in greater detail below, with reference to the figures, where: Figures 1, 2 show perspective views of a part of a belt conveyor having a conveyor belt and a scraper according to a first embodiment; Figure 1a shows an enlarged perspective view of a clamping device of Figure 1; Figure 3 shows a side view of the scraper from Figures 1, 2; Figures 4, 5 show a scraper module of the scraper of Figures 1 to 3 in a top view as well as in a partially cut side view; iviA / a / ¿u¿o / uui ¿ Figure 6 shows a cross-section through the scraper module of Figure 5 along line A..A; Figure 7 shows a perspective view of the scraper module from Figures 4, 5 which has a separate scraper element; Figures 8a, 8b, 8c, 8d, and 8e show perspective views of various positions of scraper parts according to the first modality during system carrier extraction; and Figures 9a, 9b and 9c show perspective views of the scraper according to the first modality when an extraction aid is used; Figure 10 shows a cross-sectional view along line B..B of Figure 8b; Figure 11 shows a perspective view of a portion of a belt conveyor having a conveyor belt and a scraper according to a second embodiment; Figure 12 shows a top view of a scraper system carrier from Figure 11; Figure 13 shows a side view of the scraper from Figures 11, 12; Figure 14 shows a view similar to Figure 10 for the scraper in Figures 11 to 13 according to the second modality. DETAILED DESCRIPTION OF THE INVENTION Figures 1 and 2 show perspective views, for a first modality, of a part of a belt conveyor 10 having a conveyor belt 12 which is diverted around a hiker pulley 14. A shaft of the hiker pulley is mounted on a belt scaffold 16, only parts of it are shown here in schematic form. In the belt conveyor 10, a scraper 18 having a plurality of scraper modules 26 is provided with a system carrier 24 and a clamping device 20 and counter support 22 for attachment to the belt scaffold 16. The clamping device 20 and the counter support 22 each have a joining part that is attached to the strap scaffold 16 or is part of the strap scaffold 16, herein, in each case, in the form of joining plates 28. A fastening element in the form of a fastening plate 30 in each case is attached to the joining plates 28. In the embodiment shown, the system carrier 24 is a tube of continuous round cross-section. The clamping plates 30 each have round recesses with sliding plastic bushings 33 inserted therein, in which the system carrier 24 is rotatably mounted. In Figure 3, two scraper modules 26 are shown in a side view. Each scraper module 26 includes a base element 32 that is detachably attached to the system carrier 24 by a retaining clamping device 34. A scraper arm 36 is attached to the base element 32 to allow it to pivot about a pivot axis 38. A scraper element holder 40, which has a scraper element 42 in each case, is accommodated at the end of the scraper arm 36. As can be seen, for example, from Figure 2, multiple scraper modules 26 are arranged side by side on the system carrier 24. The system carrier 24 extends in the direction of the width of the conveyor belt 12, that is, transversely to its direction of travel. In the first configuration, the side-by-side scraper modules 26 each have alternating shorter and longer scraper arms 36, such that the scraper elements 42 are arranged in two staggered rows. When viewed in the direction of travel of the conveyor belt, a slight overlap is consistently provided between the scraper elements 42 of the two rows. The scraper modules 26 are positioned side by side so that the rows extend at least substantially across the entire width of the conveyor belt 12. During the operation of the conveyor belt 10 and the scraper 18, the edges of the scraper elements 42, as shown in Figure 3, abut against the surface of the conveyor belt 12 in a detachable manner, in the example shown in the return region of the conveyor belt 12. The scraper elements 42 are pressed resiliently against the surface of the conveyor belt 12. Contaminants and adherent conveyed goods are therefore scraped off the moving conveyor belt 12 by the scraper elements 42. In Figures 4 and 5, one of the scraper modules 26 is shown in great detail. As shown there, a joint 44 is provided between the base element 32 and the scraper arm 36 so that the scraper arm 36 can be pivoted about a pivot axis 38. As shown, the joint 44 includes a stirrup 46 spanning the base element 32. A rubber torsion spring (not shown), which applies a twist to the scraper arm 36, acts inside the seal 44. A projection tab is provided as a stop 48 on the base element 32. In a stop position, a portion of the stirrup 46 rests against the stop 48 so that the scraper arm 36 can no longer pivot about the pivot axis 38. The rubber torsion spring is configured so that it acts on the scraper arm 36 in the direction of the stop, where a deflection 48 of the spring prevails in the stop position shown in Figure 5. Due to the effect of the respective springs of the scraper modules 26, the scraper elements 42 are pressed against the surface of the conveyor belt 12, but can undertake an evasive action by pivoting at the joints 44 during the influence of corresponding forces during operation, for example, due to damage to the stationary belt, elevations or the like on the surface of the conveyor belt 12 by means of a corresponding pivoting movement of the scraper arm 36 around the pivot axis 38 against the effect of the spring. A deviation of the entire scraper 18, with which the entire scraper elements 42 are pressed against the conveyor belt 12, is predefined by pre-establishing a rotation position of the system carrier 24. Therefore, a tensioning device 50 is provided in the clamping device 20 between the clamping plate 30 and the system carrier 24. Figure 1a shows the clamping device 20 in an enlarged representation. A clamping ring attached to the system carrier 24 has a tensioning arm 54 projecting radially from the system carrier 24, which can be tensioned by means of a tensioning screw 56 with respect to a joint firmly fixed to the clamping plate 30. By adjusting the tensioning screw 56, the system carrier 24 can then be rotated and a deflection of the scraper module springs 26 can be adjusted. As further shown in Figures 1, 1a, a plate-shaped support element 80, which is accommodated in the manner shown between the joining plate 28 and the clamping plate 30, is also attached to the joining plate 28 of the clamping device 20. The form and function of the support element 80 are explained in more detail below, with reference to Figures 8a to 8d and Figure 10. During the operation of scraper 18, the scraper elements 42 experience constant wear, necessitating regular inspection and maintenance. Scraper 18 is designed with a particularly simple attachment to the conveyor scaffold 16 and to the scraper modules 26. As is evident in particular from Figures 4, 5 and 7, the scraper arm 36 includes two elements that are detachably attached to each other, namely a shaft 58 connected to the scraper element holder 40 and a sleeve 60 connected to the base element 32, specifically attached to the stirrup 46 of the joint 44. The shaft 58 is inserted into the sleeve 60 (Figure 5) and is secured by means of a rotating lock 62 in the direction of a longitudinal axis 64 of the scraper arm 36. The longitudinal axis 64 extends in the configuration shown, and is evident from Figures 2 and 3, in a vertical view parallel to the direction of travel of the conveyor belt 12 and, therefore, also perpendicular, i.e., at an angle β of 90° (see Figure 8e), to the longitudinal axis of the system carrier 24. In a horizontal view from the side (Figure 3), the longitudinal axis 64 extends at an angle γ of approximately 90° to the direction of travel of the conveyor belt 12. The longitudinal axis 64 in the configuration shown is aligned perpendicular, i.e., at an angle Ζ� of 90°, to the contact edge of the scraping element 42 (see Figure 4). The shaft 58 can be freely rotated within the sleeve 60 around the longitudinal axis 64, which is why the longitudinal axis 64 is also referred to as the axis of rotation. However, a sealing ring 66 is provided which, on the one hand, seals the interior space of the sleeve 60 with respect to the shaft 58 and, on the other hand, due to friction caused by contact with the inner side of the sleeve 60, creates a certain slowness in the movement of the shaft 58 relative to the sleeve 60. The swivel lock 62 includes, on the sleeve side 60, an elongated window 62a accommodated inside, which has an edge projecting into the sleeve 60, and includes, on the shaft side 58, an elongated plate-shaped coupling element 62b that is firmly attached to the end of the shaft 58 in an extension 63 having a smaller diameter. As is evident in particular from the cross-sectional view in Figure 6, the coupling element 62b and the window 62a are formed such that the coupling element 62b, when aligned parallel to the window 62a (dash representation), can be inserted through the latter in the direction of the longitudinal axis 64, while it is locked in a twisted position with respect to parallel alignment as shown (solid line) at the edge iviA / a / zuzó / uu i ¿ ia of the window 62a. Therefore, there is a dependence of the rotation position in terms of the fixation of shaft 58 to sleeve 60 in the axial direction of the longitudinal shaft 64. In a position of the coupling element 62b parallel to the window 62a (dash representation), the shaft 58 with the scraper element 42 and the scraper element holder 40 attached thereto is located in a position within an angular release range 68a. In a rotational position within the angular release range, the rotating lock 62 is released and the shaft 58 can be freely displaced in the longitudinal direction with respect to the sleeve 60. When the shaft 58 is further twisted with respect to the sleeve 60, the ends of the coupling element 62b engage behind the edge of the window 62a so that the shaft 58 is fixed in the longitudinal direction with respect to the sleeve 60. The corresponding rotation positions of the shaft 58 are within a fixed angular range 68b, in which the rotating lock 62 is locked. As shown, the angular release range 68a is centered around the rotation position shown with dashes in Figure 6, in which the front edge of the scraper element 42 provided to abut the conveyor belt 12 is at 90° to the longitudinal direction of the system carrier 24 and to the pivot axis 38 of the scraper module 26. In contrast, the fixed angular range 68b is centered around a rotation position that is rotated 90° relative to this and is shown in Figure 6 with a solid line. In this rotation position, the edge of the scraper element 42 is aligned parallel to the longitudinal direction of the system carrier 24 and to the pivot axis 38 of the joint 44. Due to the free rotation of shaft 58 within sleeve 60, the respective scraper element 42, during contact with the conveyor belt 12, can align itself according to its contour. In practice, this alignment will not be consistently flat across the entire width of the belt but will curve, for example, towards the edges. Due to the contact pressure, the scraper element fasteners 40 are constantly positioned so that the scraper elements 42 follow the shape of the conveyor belt 12. However, a rotational position within the angular release range 68a is not achieved under any operating conditions. The rotary lock 62 therefore remains constantly within the fixed angular range during contact of the scraper element 42 with the conveyor belt 12, thus ensuring the attachment of the respective scraper modules 26 to the base element 32. In order to allow work on the scraper 18 and the scraper modules 26, in particular to make it possible to change the unit comprising the scraper element 42, the scraper element holder 40 and the shaft 26, the system carrier 42 with the scraper modules 26 attached to it can be separated in a particularly simple manner and are pulled out laterally, as explained below with reference to Figures 8a to 8e. Therefore, on the side of the clamping device 20, a particular connection of the clamping plate 30 to the connecting plate 28 is provided, and on the side of the counter support 22, a bearing of the system carrier 24 in the bearing bushing 33 of the clamping plate 30 is provided so that the latter can move freely in its longitudinal direction. As shown in Figure 1a, the clamping plate 30 is fixed to the joining plate 28 of the clamping device 20 by two socket connections 70 and one screw connection 72. The socket connections 70 are formed by two bolts arranged parallel to each other at a distance from each other on the joining plate 28, which are received so as to fit precisely into the perforations of the clamping plate 30. The socket connections 70 can be separated by removing the clamping plate 30 from the joining plate 28 in the longitudinal direction of the system carrier 24. The screw connection 72 formed between the plug connections 70 includes a screw aligned parallel to the bolts, with that screw the clamping plate 30 is screwed to the joining plate 28. In an operating arrangement for operating the belt conveyor 10 and the scraper 18, the clamping plate 30 is fixed to the joining plate 28 by means of the screw connection 72. If the operation is interrupted, parts of the scraper 18 that are to be retained can be removed by transferring the scraper 18 to an assembly arrangement. By releasing the screw connection 72, the clamping plate 30 can be separated from the joining plate 28, subsequently also separating the plug connections 70a, 70b by pulling in the direction of the longitudinal axis of the system carrier 24. A handle 74 is provided for this purpose. Figure 8a shows, starting from the operational arrangement, first of all the release of the screw connection 72. The clamping plate 30 is subsequently removed from the joining plate 28, together with the system carrier 24 in the longitudinal direction thereof, where the plug connections 70a, 70b are separated. As already mentioned, the clamping device 20 between the joining plate 28 and the clamping plate 30 includes the support element 80. The support element 80 has, as is evident from Figure 8b, a hook-shaped clamping portion 82 extending in the direction of the system carrier 24 and partially encompassing it, which forms a recess 86. The clamping portion 82 and the recess 86 have, as shown, an inner contour (in this case round) in some sections corresponding to the outer contour (in this case round) of the system carrier 24. The clamping portion 82 is accommodated in the operating arrangement, i.e., if the clamping plate 30 is attached to the joining plate 28, such that it does not touch the system carrier 24, but remains at a certain distance of a few millimeters from it.Above the clamping portion 82, the support element 80 has a cutout 84 through which the system carrier 24 passes. In the assembly arrangement, i.e., following the separation of the screw connection 72 and the socket connections 70a, 70b (Figure 8b), the system carrier 24 is slightly submerged and subsequently rests on the clamping portion 82 of the support element 80 in the recess 86. After separating the connection between the clamping plate 30 and the joining plate 28, the support element 80 then assumes the clamping of the system carrier 24. As shown, the support element 80 is clamped to the clamping plate 28 and thus to the strap scaffold 16. As shown in Figure 10, the clamping portion 82 spans the system carrier 24. 1 over a circumferential region at approximately 135° in the hollow 86 and supports the system carrier 24 from below so that the latter does not fall off. In the next step, the system carrier 24 is now removed along its longitudinal axis, along with the clamping plate 30 and the tensioning device 50 (Figure 8b). During this process, the support element 82 supports the system carrier 24, preventing it from falling. Due to the system carrier 24's ability to move within the bearing bushing 33 of the counter-support 22, it can be easily removed partially. The scraper modules 26 can pass through the joining plate 28 and the support element 80 because the hook shape of the clamping portion 82 only partially spans the system carrier 24, with the cutout 84 leaving sufficient clearance so that when the system carrier 24 is removed, the scraper modules 26 can be transferred to an extracted position outside the belt region (Figure 8d). The scraper modules 26 can then be guided through a clear area in the plane of the support element 80 and the joining plate 28 without impact. The cutout 84 of the support element 80 forms part of this clear area. In the extended position, the scraper modules 26 are easily accessible and can be inspected and maintained. In particular, worn scraper elements 42 can be replaced by separating the respective units made of the scraper element 42, the scraper element holder 40, and the shaft 58 from the respective scraper module as described above, by twisting them around the rotation axis 64, separating them by removing them in the longitudinal direction, and then joining new elements in the same manner. Therefore, the inspection and maintenance process for the scraper 18 becomes particularly easy. In the configuration shown, the system carrier 24 and the scraper modules 26 can be removed laterally simply by loosening a single screw (screw connection 72). Thanks to the support provided by the support element 80, this can be carried out by a single person. If sufficient space is available on the side of the conveyor belt 12, handling the system carrier 24 can be made even easier when it is removed using an extraction aid. For this purpose, as shown in Figure 9a, an adapter 76 can first be fitted laterally onto the system carrier 24 and clamped to it or otherwise fixed to it. Subsequently, a tube can be attached to the adapter 76; this tube serves as an extraction aid 78 and is attached as an extension of the system carrier 24. By means of the extraction aid 78, the system carrier 24 can be handled particularly well, especially in connection with the support at the clamping portion 82 of the support element 80. A scratcher 118, according to a second modality, is shown in Figures 11 to 14. Scratcher 118 according to the second modality corresponds, in numerous details, to scratcher 18 according to the first modality, so that only the differences are explained in greater detail below, and reference is made in other respects to the description mentioned above. The same reference numbers denote elements that correspond between the modalities. Meanwhile, in the case of scraper 18 according to the first modality as described and shown, the scraper elements 42 are arranged in two rows, scraper 118 according to the second modality includes a single-row arrangement of scraper elements 42 in scraper modules 126 which are identical in length and which are arranged next to each other in the system carrier 24. As is particularly evident from Figure 12, the scraping edges of the scraper elements 42 are not aligned in the transverse direction of the conveyor belt 12, as in the first mode, but obliquely to it at an angle which, in the example shown, is approximately 15°. However, the scraper arms 36 extend with their longitudinal axis 64, as in the first mode, in the longitudinal direction of the conveyor belt 12, that is, as in the first mode, at an angle β of 90°. The scraper elements 42 are attached obliquely at an angle δ of approximately 75° to the scraper arms 36. Adjacent scraper modules 126 on the system carrier 24 are arranged so closely that, viewed in the longitudinal direction of the conveyor belt 12, a slight overlap of the scraper elements 42 occurs, thus resulting in a scraping effect over the entire width of the belt. In other respects, the scraper 118 according to the second embodiment is identical in terms of structure and function to the scraper 18 according to the first embodiment, that is, in common with the scraper 18, each scraper 118 includes the base element 32 which is detachably attached to the system carrier 24 in the retention clamping device 34 as well as the scraper arm 36 which is pivotally attached about a pivot axis 38 and at each end of which is accommodated a scraper element holder 40 which has the scraper element 42. The deflected torsion spring imparts a twist so that, during the operation of the scraper 118, the scraping edges of the scraper elements 42 abut against the surface 12 of the conveyor belt 12 in a detachable manner and are resiliently pressed against the surface 12 thereof to scrape contaminants.If there are stationary obstacles in the path of the conveyor belt 12, the scraper elements 42 can take evasive action due to a pivoting movement of the scraper arm 36 around the pivot axis 38 against the effect of the spring. Figure 13 shows, for the second mode, a horizontal view from the side, from where the angle γ between the direction of travel of the conveyor belt 12 and the longitudinal axis 64 can be observed. Depending on the arrangement and configuration, the angle γ can be, for example, between 0 and 20°; in the mode shown, the angle γ is approximately 15°. In the second configuration as well, the scraper arm 36 includes the shaft 58 attached to the scraper element holder 40, where the shaft is inserted into the sleeve 60 and can be rotated around the longitudinal axis 64 within it. The rotating lock 62 ensures that the shaft 58 can only be removed from or inserted into the sleeve 60 in the corresponding alignment, i.e., rotated from the normal position defined by the belt contact 60.

Claims

1. A scraper for a conveyor belt (12), characterized in that it has - a system carrier (24) with at least one scraper module (26, 126), - wherein the scraper module (26, 126) has a base element (32) accommodated in the system carrier (24) and a scraping element (42) for abutting the conveyor belt (12), - wherein the scraping element (42) is rotatably connected with a rotary coupling about a rotation axis (64) with respect to the base element (32), wherein the rotary coupling is configured such that, - in a rotational position of the scraping element (42) within a fixed angular range (68b), the scraping element (42) is firmly coupled to the base element (32) in the direction of the rotation axis (64), - and in a rotational position of the scraping element (42) within a release angular range (68a),The scraping element (42) can be separated from the base element (32) in the direction of the rotation axis (64).

2. The scraper according to claim 1, further characterized in that - the rotary coupling has an insertion opening (62a) and a coupling element (62b) which are configured such that the coupling element (62b) in a rotational position within the angular release range (68a) can be guided through the insertion opening (62a) and the coupling element (62b) is secured to the insertion opening (62a) in a rotational position within the fixed angular range (68b).

3. The scraper according to claim 2, further characterized in that the coupling element (62b) is accommodated on a shaft (58) which can be inserted into an insertion sleeve (60), wherein the insertion opening (62a) is formed within the insertion sleeve (60), - wherein a flange of the insertion opening (62a) is configured to project inwards into the insertion sleeve (60).

4. The scraper according to claim 3, further characterized in that - the shaft (58) or the insertion sleeve (60) is firmly connected to the scraping element (42).

5. The scraper according to any of the preceding claims, further characterized in that - the axis of rotation (64) has an angle (β) of more than 60° with respect to the system carrier (24), preferably accommodated at least substantially perpendicular.

6. The scraper according to any of the preceding claims, further characterized in that - the fixed angular range (68b) extends, starting from a mid-position, at least over + / 30°.

7. The scraper according to any of the preceding claims, further characterized in that - the rotary coupling has a shaft (58) which can be inserted into an insertion sleeve (60), - wherein a friction element (66) for stopping against the shaft (58) and / or an inside of the insertion sleeve (60) is provided to dampen relative movement between the shaft (58) and the insertion sleeve (60) against each other.

8. The scraper according to any of the preceding claims, further characterized in that - the rotary coupling has a shaft (58) which can be inserted into an insertion sleeve (60), - wherein a sealing element (66) is provided to seal between the shaft (58) and an inside of the insertion sleeve (60).

9. The scraper according to any of the preceding claims, further characterized in that - the scraper module (26, 126) has a joint (44), wherein the scraping element (42) can be pivoted on the joint (44) with respect to the system carrier (24).

10. The scraper according to claim 9, further characterized in that - a spring element is provided to act on the scraping element (42) in the direction of the conveyor belt (12).

11. The scraper according to claim 9 or 10, further characterized in that - the scraping element (42) is connected via a scraper arm (36) to the joint (44), - wherein the rotation coupling is formed in the scraper arm (36).

12. The scraper according to any of claims 9 to 11, further characterized in that - a stop (48) is provided for the pivot movement of the scraping element (42).

13. A scraper module (26, 126) for a scraper (18, 118) according to any of the preceding claims, characterized in that it has - a base element (32) and a scraping element (42), wherein the scraping element (42) is rotatably attached with a rotary coupling about a rotation axis (64) with respect to the base element (32), - wherein the rotary coupling is configured such that - in a rotational position of the scraping element (42) within a fixed angular range (68b), the scraping element (42) is firmly coupled to the base element (32) with respect to movement in the direction of the rotation axis (64), - and in a rotational position of the scraping element (42) within a release angular range (68a), the scraping element (42) can be separated from the base element (32) in the direction of the rotation axis (64).

14. A belt conveyor, characterized in that it has - a conveyor belt (12), - and a scraper (18, 118) according to any one of claims 1 to 12, - wherein the system carrier (24) is aligned transversely to the conveyor belt (12) - and the scraper element (42) abuts the conveyor belt. 5 15.A method for exchanging a scraping element (42) in a scraper (18, 118) according to any of claims 1 to 12 or in a belt conveyor (10) according to claim 14, characterized in that - the system carrier (24) is brought to a position in which the scraping element (42) is at a sufficient distance from the conveyor belt (12) so that it can be rotated to a rotational position within the angular release range (68a), - the scraping element (42) is separated from the base element (32), - a new scraping element (42), placed in a rotational position within the angular release range (68a), is attached to the base element (32) and is rotated to a rotational position within the fixed angular range (68b).

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