Conveyor belt scraper

Abstract

A scraper (60) or cleaner tip for a belt (11) of a conveyor belt machine (10) has a retaining body (62) made of a first metal or alloy material. The retaining body is configured or adapted to be connected to a mounting assembly (20) of the conveyor belt machine. The blade also has a blade element (64) coupled to the retaining body. The scraper element is configured or adapted to scrape from the belt any transport material (12) adhering to the belt. The blade element has a single tungsten carbide blade (70) joined to a backing strip (66) by brazing. The backing strip is made of a second metal or alloy material having the same or similar thermal properties as the first metal or alloy material of the holding body. The backing strip of the so assembled blade element (64) is then joined to the retaining body. The blade thus provided allows the single tungsten carbide blade to substantially extend the length of the retention body.

Description

Technical Field

[0001] This disclosure relates to a conveyor belt scraper, also known as a conveyor belt cleaner tip, for removing residual material that adheres to or is attached to the surface of a conveyor belt machine.

[0002] This invention is particularly applicable to conveyor belts for conveying bulk materials such as coal, coke and iron ore, but is not limited thereto, and can have a wider range of applications, such as conveying any material with adhesive properties.

[0003] This invention can have a wider range of applications in machines, chute slots or other components where individual tungsten carbide blades need to be reliably and efficiently connected to a body made of stainless steel or low-carbon steel. Background Technology

[0004] Over the years, many conveyor belt cleaning systems have been developed that include belt scrapers, which have a body that holds specialized teeth or blades on the surface of the conveyor belt to scrape off material adhering to the return side of the belt while maintaining the strength and integrity of the belt to ensure its long-term use.

[0005] For example, in the Australian coal industry, conveyor belts that transport coal and coke utilize belt scrapers made of a stainless steel or low-carbon steel body, also known as a retainer body, which holds scraper elements having multiple (usually three or four) tungsten carbide blades (also known as inserts) arranged to be brazed to a common edge of the body, but protruding end-to-end from that common edge at a desired common angle, tightly separated segments.

[0006] Multiple such belt scrapers arranged end-to-end need to extend across (and provide sufficient scraper elements to scrape) the entire (or effective) width of the conveyor belt. The angle at which the scraper elements protrude from the steel body varies depending on the type of belt scraper, especially those known as H-type, P-type, and R-type scrapers, each of which is particularly suitable for cleaning the belt at different locations.

[0007] In the prior art, the aforementioned scraper with blades is employed and widely used. This scraper utilizes multiple end-to-end but closely separated tungsten carbide blade segments as scraper elements, rather than a single tungsten carbide blade that essentially extends the length of the steel body. This has limitations, particularly in the manufacturing stage. This is mainly because, during manufacturing, brazing is used to melt the silver-based filler material, allowing it to flow and form a joint between the multiple tungsten carbide blades and the steel body. However, at the high temperatures achieved through brazing, the steel expands (and then contracts during cooling) significantly more than the tungsten carbide due to the very different thermal properties of steel and tungsten carbide, especially their coefficients of thermal expansion.

[0008] During the subsequent cooling phase, as the joint solidifies, the shrinkage of the steel body far exceeds that of the tungsten carbide blade, causing the steel body to continue shrinking even after the tungsten carbide blade has stopped shrinking. Since the steel body connecting two adjacent blades is still shrinking, the end surfaces facing any two adjacent tungsten carbide blades come closer together, thus reducing the gap between them.

[0009] While this process (including the presence of gaps) reduces the likelihood of manufactured scrapers becoming noticeably bent, deformed, or even cracked, it is not without its limitations, as it is still possible (and not uncommon) to produce scrapers that are slightly bent, requiring manual physical straightening if they are to be used.

[0010] This problem is particularly severe when attempting to braze a single tungsten carbide insert along essentially the length of the scraper-bearing steel body, thus hindering the adoption and widespread use of any such single-insert scraper-bearing insert. However, the problem is less severe when brazing multiple tungsten carbide inserts along the length of the scraper-bearing steel body, although it is still a concern.

[0011] In addition to these manufacturing issues, there are also problems associated with the performance and long-term use of this existing belt scraper. It is not uncommon for the portion of the facing end surface (especially the corner edge of the blade closest to the belt) that crosses the gap between any two adjacent tungsten carbide blades, especially under the strong impact of the conveyed bulk material, to crack or break abruptly, causing damage to the belt. Furthermore, with prolonged use, as the large amount of material conveyed on the belt causes wear on the corner edges of the blades and other scraping surfaces, the gap between adjacent blades gradually widens, which reduces the scraping efficiency of this belt scraper over time.

[0012] The object of the present invention is to provide a conveyor belt scraper that overcomes or at least substantially improves the aforementioned problems and disadvantages of the prior art, or at least provides a useful alternative.

[0013] Another object of the present invention is to provide a conveyor belt scraper having a single tungsten carbide blade that substantially extends to maintain the length of the body, and is easier to manufacture and does not have the manufacturing problems associated with scrapers or cleaner tips having multiple tungsten carbide blades, and has a longer service life than prior art scrapers. Summary of the Invention

[0014] According to one aspect of the present invention, a scraper for a belt in a conveyor belt machine is provided, the scraper comprising: (a) A retaining body made of a first metal or alloy material and having a certain length, the retaining body being adapted to be connected to an installation assembly of a conveyor belt machine, and (b) A scraper element, which is connected to a retaining body and adapted to scrape any conveying material adhering to the belt from the belt, the scraper element comprising a single tungsten carbide blade having a length substantially extending the length of the retaining body, the single tungsten carbide blade being brazed to a backing strip made of a second metal or alloy material having thermal properties the same as or similar to the first metal or alloy material of the retaining body, the backing strip of the scraper element thus assembled being connected to the retaining body such that the single tungsten carbide blade substantially extends the length of the retaining body.

[0015] In a preferred embodiment, the retaining body includes a variable protruding wall portion to which a backing strip for the scraper element is connected, wherein the variable protruding wall portion extends along its length from the mounting wall portion to different height ranges, and a weld joint is formed along a variable path that follows the outer line / outer contour of the variable protruding wall portion.

[0016] The backing strip is preferably an L-shaped cross-section backing strip.

[0017] Alternatively, the backing strip can be a flat-section backing strip.

[0018] The variable protruding wall portion is preferably arranged in a serrated pattern.

[0019] In this preferred form, the weld joint is a serrated weld joint.

[0020] Alternatively, the variable protruding wall portion can be arranged with a corrugated surface.

[0021] In this preferred form, the weld joint is a weld joint with a corrugated surface shape.

[0022] Preferably, the first metal or alloy material is selected from stainless steel or low-carbon steel.

[0023] Preferably, the second metal or alloy material is selected from stainless steel or low-carbon steel.

[0024] The backing strip of the scraper element can be welded to the retaining body.

[0025] Individual tungsten carbide blades can be connected to the backing strip via induction brazing.

[0026] Preferably, the metal filler material is used for induction brazing.

[0027] The preferred metallic filler material is a silver-based filler material.

[0028] Preferably, the silver-based filler material is in the form of a trilay structure.

[0029] According to another aspect of the present invention, a method for assembling a scraper for a conveyor belt machine is provided, the method comprising the following steps: (a) Provide a retaining body made of a first metal or alloy material and having a certain length, (b) Provide a single tungsten carbide blade having a length that substantially extends the length of the retaining body. (c) Provide a backing strip made of a second metal or alloy material, the thermal properties of which are the same as or similar to those of the first metal or alloy material of the retaining body. (d) Brazing individual tungsten carbide blades to a backing strip to form an assembled scraper element, and (e) Connect the assembled scraper element to the retaining body such that the individual tungsten carbide blade substantially extends the length of the retaining body.

[0030] Preferably, the step of brazing a single tungsten carbide blade to the backing strip is performed by induction brazing.

[0031] Preferably, the step of connecting the assembled scraper element to the retaining body is by welding.

[0032] Therefore, the more important features of the invention have been outlined rather extensively in order to better understand and practice the following detailed description of the invention, and to better appreciate the contribution to the art.

[0033] Other features of the invention will be described below. Therefore, those skilled in the art will understand that the concepts upon which this disclosure is based can readily be used as the basis for designing other structures, components, method steps, and system configurations to achieve the objectives of the invention. Therefore, it is important that the general outline of the invention described above be considered to include these equivalent features, provided they do not depart from the spirit and scope of the invention. Attached Figure Description

[0034] Figure 1 It is an isometric view of one end of a conventional conveyor belt machine, to which a prior art conveyor belt scraper or conveyor belt cleaner tip engages to clean adhering particulate material from the surface on the return side of the belt.

[0035] Figure 2 yes Figure 1 The side view of the conveyor belt machine shown.

[0036] Figure 3 This is an isometric view of the existing H-type scraper.

[0037] Figure 4 It is an isometric view of the existing R-type with scraper.

[0038] Figure 5This is an isometric view of the existing P-type with a scraper.

[0039] Figure 6 yes Figure 3 An isometric exploded view of the existing H-type scraper.

[0040] Figure 7 yes Figure 3 The existing technology H-type with scraper side sectional view.

[0041] Figure 8 yes Figure 5 A side sectional view of the existing P-type scraper.

[0042] Figure 9 yes Figure 4 The existing technology R-type with scraper side sectional view.

[0043] Figure 10 This is a top isometric view of the tip of a (H-type) conveyor belt scraper or conveyor belt cleaner according to the first embodiment of the present invention.

[0044] Figure 11 yes Figure 10 An isometric view of the conveyor belt scraper from below.

[0045] Figure 12 yes Figure 10 and Figure 11 An isometric exploded view of a scraper element of a conveyor belt scraper, which can be fixed to a retaining body for connection to a mounting assembly of a conveyor belt machine.

[0046] Figure 13 yes Figure 12 A side sectional view of the scraper component during assembly.

[0047] Figure 14 yes Figure 13 An isometric view of the assembled scraper element, which is adjacent to the retaining body to which it will be fixed.

[0048] Figure 15 yes Figure 10 and Figure 11 A side sectional view of a conveyor belt scraper, wherein Figure 14 The scraper element and the retaining body are fixed together.

[0049] Figure 16 yes Figure 15 An isometric view of the conveyor belt scraper, with Figure 10 same.

[0050] Figure 17 This is an isometric view of the tip of a (P-type) conveyor belt scraper or conveyor belt cleaner according to a second embodiment of the present invention.

[0051] Figure 18 This is an isometric view of the tip of a (R-type) conveyor belt scraper or conveyor belt cleaner according to a third embodiment of the present invention.

[0052] Figure 19 yes Figure 18 A side sectional view of the R-type with a scraper.

[0053] Figure 20 yes Figure 17 A side sectional view of the P-type with a scraper.

[0054] Figure 21 This is a side view of the end portion of a conventional conveyor belt machine, to which a prior art HT-type belt scraper or belt cleaner tip engages for initial cleaning of adhering particulate material on the return side of the belt.

[0055] Figure 22 yes Figure 21 The image shows a top isometric view of the prior art HT type with a scraper.

[0056] Figure 23 yes Figure 22 An isometric view of the HT type with a scraper from below.

[0057] Figure 24 yes Figure 22 and Figure 23 Side view of the HT type with scraper.

[0058] Figure 25 This is a top isometric view of the tip of a (HT type) conveyor belt scraper or conveyor belt cleaner according to the fourth embodiment of the present invention.

[0059] Figure 26 yes Figure 25 An isometric view of the HT type with a scraper from below.

[0060] Figure 27 yes Figure 25 and Figure 26 Side view of the HT type with scraper. Detailed Implementation

[0061] Figure 1 and Figure 2 The conventional conveyor belt machine 10 shown conveys particulate or bulk materials 12 (such as coal, coke, and iron ore) on its belt 11 in the direction indicated by arrow A, and any residual "carry-back" material of those materials 12 does not fall off from the end of the belt 11, but rather adheres or sticks to the surface on the return side 13 of the belt 11. This material is substantially removed by the sequential action of prior art H-type scrapers 14, P-type scrapers 16, and R-type scrapers 18, each of which is respectively connected to a dedicated suspension arm and mounting assembly 20, 22, 24 of the conveyor belt machine 10.

[0062] Figure 3 and Figure 7 The prior art H-type scraper 14 shown has an H-type retaining body 26 to which the scraper element 28 is fixed.

[0063] like Figure 6 and Figure 7 As shown more clearly in the diagram, the scraper element 28 includes a conventional three-layer structure 30 for brazing processes. This three-layer structure 30 is made of a conventional metallic filler material, such as laminated foil or a filler material in the form of a three-layer structure known as a "trimetallic brazing alloy," sandwiched between the stepped portion 32 of the retaining body 26 and four tungsten carbide sheets or tungsten carbide blades 34. As those skilled in the art will appreciate, the three-layer structure 30 is a three-layer structure having two outer silver-based brazing filler materials that are wrapped around a copper intermediate layer (or carrier filler material) in a suitable 1:2:1 (1:2:1) size ratio. In this example of the prior art, an induction brazing process is used to melt the metallic filler material of the three-layer structure 30, allowing it to flow and effectively connect the four tungsten carbide blades 34 to the retaining body 26. Although induction brazing is used in this example of the prior art, other suitable brazing techniques, such as silver brazing, sometimes also called hard brazing, can be used alternatively.

[0064] During the manufacture of the H-type scraper 14, when the assembled components of the scraper 14 are heated and cooled, the presence of an expansion joint 36 or gap between any two adjacent tungsten carbide blades 34 typically accommodates the expansion and contraction effects of different metals. It is well known that tungsten carbide cools from high temperatures at a very different rate than steel because the thermal properties of the two materials are very different.

[0065] Figure 5 and Figure 8 The prior art P-type scraper 16 shown has a P-type retaining body 38 to which the scraper element 40 is fixed.

[0066] The scraper element 40 includes a conventional three-layer structure 30 sandwiched between the stepped portion 42 of the retaining body 38 and three tungsten carbide sheets or tungsten carbide blades 44. For the reasons described above, the three tungsten carbide sheets or tungsten carbide blades 44 are separated end to end by expansion joints 46, and the three tungsten carbide blades 44 are connected to the retaining body 38 by a brazing process as described above.

[0067] Figure 4 and Figure 9 The prior art R-type scraper 18 shown has an R-type retaining body 48 to which the scraper element 50 is fixed.

[0068] The scraper element 50 includes a conventional three-layer structure 30 sandwiched between the stepped portion 52 of the retaining body 48 and three tungsten carbide sheets or tungsten carbide blades 54. For the reasons described above, the three tungsten carbide sheets or tungsten carbide blades 54 are separated end to end by expansion joints 56, and the three tungsten carbide blades 54 are connected to the retaining body 48 by a brazing process as described above.

[0069] In a broad form of the invention, and as illustrated in the accompanying drawings depicting various specific embodiments of the invention, a scraper 60, 90, 110, 160, or cleaner tip is provided for a belt 11 of a conveyor belt machine 10. The scraper has a retaining body 62, 92, 112, 162 made of a first metal or alloy material and having a certain length. The retaining body is configured or adapted to be connected to mounting assemblies 20, 132 of the conveyor belt machine. The scraper also has scraper elements 64, 164 connected to the retaining body. The scraper elements are configured or adapted to scrape away any conveyor material 12 adhering to the belt. The scraper elements have a single tungsten carbide blade 70, 170, the length of which substantially extends the length of the retaining body, and the single tungsten carbide blade is brazed to a backing strip 66, 168. The backing strip is made of a second metal or alloy material, the thermal properties of which are the same as or similar to the first metal or alloy material of the retaining body. The backing strip of the scraper element, thus assembled, is then connected to the retaining body. The scraper thus provides a single tungsten carbide blade that substantially extends the length of the retaining body.

[0070] More specifically, Figures 10 to 16 A conveyor belt scraper or conveyor belt cleaner tip 60 according to a more specific first embodiment of the invention is shown. The scraper 60 is H-shaped but has an improved H-shaped retaining body 62, which is preferably made of stainless steel but may also be made of low carbon steel or other suitable metal or alloy material, and the improved scraper element 64 is fixed to the improved H-shaped retaining body 62.

[0071] like Figures 12 to 15 As shown more clearly in the diagram, the scraper element 64 includes: a central L-shaped cross-section three-layer structure 68 for brazing processes and preferably made of conventional filler material; a thin L-shaped cross-section backing strip 66 or plate on one side of the three-layer structure 68, preferably made of stainless steel, but may alternatively be made of low-carbon steel or other suitable metal or alloy material; and a single tungsten carbide blade or blade 70 on the other side of the three-layer structure 68, which provides a scraping edge 71.

[0072] L-shaped cross-section backing strip 66 is connected to retaining body 62 along at least one of its first surfaces.

[0073] The L-shaped cross-section backing strip 66 is also connected to a single tungsten carbide blade 70 via a three-layer structure 68 along at least one of its opposite second surfaces.

[0074] In the first step of assembling the scraper 60, an L-shaped cross-section three-layer structure 68 is securely brazed between the L-shaped cross-section backing strip 66 and the individual tungsten carbide blades 70 using a suitable brazing process to form or assemble the scraper element 64. In this embodiment, an induction brazing process is used to melt the filler material of the three-layer structure 68, allowing it to flow and effectively connect the individual tungsten carbide blades 70 to the retaining body 62. Although induction brazing is used in this embodiment of the invention, other suitable brazing techniques, such as silver brazing, sometimes also called hard brazing, can be used alternatively.

[0075] As is well known to those skilled in the art, in order to form a brazed joint between two metal or metal alloy surfaces, the L-shaped cross-section three-layer structure 68 must include a filler material with a melting point lower than that of the two surfaces being joined. For example, a metallic filler material having two outer strips (or layers) primarily composed of silver with lower concentrations of other common filler metals (such as zinc, nickel, manganese, and optionally cadmium) can be used, coated on a copper core strip. When sufficiently heated by electromagnetic induction, the filler material melts and then flows capillarily upon cooling, bonding the two surfaces together to form a joint.

[0076] Then, in the second step of assembling the scraper 60, the L-shaped backing strip 66 of the assembled scraper element 64 is fixed to the L-shaped step portion 72 of the retaining body 62 by a suitable welding process (such as laser welding, or possibly by plasma welding, or by conventional TIG welding or MIG welding) or by a suitable fastening process using mechanical fasteners or other connecting devices.

[0077] In this embodiment, before fixing the assembled scraper element 64 to the retaining body 62 in the second step, induction brazing is used as the first step in assembling the scraper element 64. Furthermore, the use of a backing strip 66 in the induction brazing process results in a significantly lower torsional force on the scraper element 64 (particularly the individual tungsten carbide blades 70 included in the scraper element 64) during shrinkage under the high temperatures applied in the aforementioned induction brazing process compared to the scraper elements of prior art scrapers. Without being bound by theory, this is likely primarily due to the use of the backing strip 66 to which the individual tungsten carbide blades 70 are brazed, and that the backing strip is made of the same or similar material (particularly its thermal properties) as the retaining body 62. These features enable the facing surfaces of the backing strip 66 and the retaining body 62 to be joined in a second step by heating (e.g. by welding) at a lower temperature than that used in the prior art, where the backing strip is not used, and multiple tungsten carbide blades are joined to the retaining body via a three-layer structure using a high-temperature brazing process to form or assemble the prior art scraper in a single step.

[0078] The H-shaped retaining body 62 has a serrated arrangement 73 that forms a variable protruding wall portion 74, which extends vertically along its length from a larger mounting wall portion 76 to different height ranges (e.g., ...). Figure 10 , Figure 14 and Figure 16 as shown in detail).

[0079] Bolts or studs are adapted to pass through holes 78 in the mounting wall portion 76 to connect the scraper 60 to the cantilever arm and mounting assembly 20 of the conveyor machine 10 (see...). Figure 1 and Figure 2 ).

[0080] like Figure 15 As shown, the surface 80 of the protruding wall portion 74 facing away from the bolt hole 78 and the adjacent surface 82 of the mounting wall portion 76 (located on the side of the protruding wall portion 74 opposite to the side facing the bolt hole 78) form an L-shaped step portion 72 for retaining the main body 62, and the L-shaped cross-section backing strip 66 of the assembled scraper element 64 is welded to the L-shaped step portion 72.

[0081] In this embodiment of the invention, such as Figure 10 and Figure 16 As shown, the serrated weld joint 84 is formed along a variable path that follows the outer line (or profile) of the serrated arrangement 73 of the variable protruding wall portion 74. Because the path of the serrated weld joint 84 between the body 62 and the scraper element 64 is not linear, the non-linear or variable path of the serrated weld joint 84 significantly extends the service life of the scraper 60 compared to the shorter service life of prior art scrapers.

[0082] As long as at least some portions of the serrated weld joint 84 between the scraper element 64 and the variable protruding wall portion 74 have a sufficiently strong bond, the scraper 60 can remain operational, even though prolonged use may cause gradual wear on portions of both the scraper element 64 and the variable protruding wall portion 74, as well as on the scraping edge 71 of the serrated weld joint 84 closer to the scraper element 64 than on the mounting wall portion 76.

[0083] like Figure 11 and Figure 15 As shown, in addition to the sawtooth welded joint 84, there is also a linear welded joint 86 formed along the exposed joint of the L-shaped cross-section backing strip 66 and the mounting wall portion 76.

[0084] Figure 17 and Figure 20 Another conveyor belt scraper or conveyor belt cleaner tip 90 according to a more specific second embodiment of the invention is shown. The scraper 90 is P-type, but has an improved P-type retaining body 92, which is preferably made of stainless steel, but may also be made of low carbon steel or other suitable metal or alloy material, on which the same improved scraper element 64 as used in the H-type scraper 60 is fixed.

[0085] The same features of the same scraper element 64 in the P-type scraper 90 and the H-type scraper 60 are identified by the same numerals in the accompanying drawings and the following description. Due to the identical structure of the scraper element 64, and due to the use of a suitable brazing process in the first step of assembling the scraper 90 to firmly braze the three-layer structure between the backing strip and the individual tungsten carbide blade to form or assemble the scraper element 64, and because the backing strip of the assembled scraper element 64 is then fixed to the holding body 92 by heating at a lower temperature (e.g., by welding) in the second step of assembling the scraper 90, the torsional force experienced by the P-type scraper 90 during the shrinkage period (in its manufacture) from the high temperature applied in the above-described brazing process is also significantly less than that experienced by prior art scrapers, for the reasons described above with reference to scraper 60.

[0086] The P-type retaining body 92 also has a serrated arrangement 93 that forms a variable protruding wall portion 94, which in this embodiment extends along its length from the mounting wall portion 96 longitudinally or in the same direction to different height ranges (e.g., Figure 17 as shown in detail).

[0087] Bolts or studs 98 passing through holes in the mounting wall portion 96 connect the scraper 90 to the suspension arm and mounting assembly 22 of the conveyor belt machine 10 (see...). Figure 2 ).

[0088] The L-shaped step portion 102 is formed on the retaining body 92, and the L-shaped cross-section backing strip 66 of the assembled scraper element 64 is welded to the retaining body 92 along a variable path following the outer line (or contour) of the serrated arrangement 93 to form the aforementioned serrated weld joint 84. There is also a linear weld joint 86 formed along the exposed joint of the L-shaped cross-section backing strip 66 and the mounting wall portion 96.

[0089] For the reasons described above with reference to scraper 60, the serrated weld joint 84 of scraper 90 significantly extends the service life of scraper 90 compared to the shorter service life of existing scrapers.

[0090] Figure 18 and Figure 19 Another conveyor belt scraper or conveyor belt cleaner tip 110 according to a more specific third embodiment of the invention is shown. The scraper 110 is R-shaped but has an improved R-shaped retaining body 112, which is preferably made of stainless steel but may alternatively be made of low carbon steel or other suitable metal or alloy material, on which the same improved scraper element 64 as used in the H-shaped scraper 60 and P-shaped scraper 90 is fixed.

[0091] The same features of the same scraper element 64 in the R-type scraper 110, H-type scraper 60, and P-type scraper 90 are identified by the same numerals in the accompanying drawings and the following description. Due to the identical structure of the scraper element 64, and because a suitable brazing process is used in the first step of assembling the scraper 110 to firmly braze the three-layer structure between the backing strip and the individual tungsten carbide blade to form or assemble the scraper element 64, and because the backing strip of the assembled scraper element 64 is then fixed to the holding body 112 in the second step of assembling the scraper 110 by heating at a lower temperature (e.g., by welding), the torsional force experienced by the R-type scraper 110 during shrinkage (in its manufacture) from the high temperature applied in the aforementioned brazing process is also significantly less than that experienced by prior art scrapers, for the reasons described above with reference to scrapers 60 and 90.

[0092] The R-shaped retaining body 112 also has a serrated arrangement 113 that forms a variable protruding wall portion 114, which in this embodiment extends along its length from the mounting wall portion 116 longitudinally or in the same direction to different height ranges (e.g., Figure 18 as shown in detail).

[0093] Bolts or studs 118 passing through holes in the mounting wall portion 116 connect the scraper 110 to the suspension arm and mounting assembly 24 of the conveyor machine 10 (see...). Figure 2 ).

[0094] The L-shaped step portion 122 is formed on the retaining body 112, and the L-shaped cross-section backing strip 66 of the assembled scraper element 64 is welded to the retaining body 112 along a variable path following the outer line (or contour) of the serrated arrangement 113 to form the aforementioned serrated weld joint 84. There is also a linear weld joint 86 formed along the exposed joint of the L-shaped cross-section backing strip 66 and the mounting wall portion 116.

[0095] For the reasons described above with reference to scrapers 60 and 90, the serrated weld joint 84 of scraper 110 significantly extends the service life of scraper 110 compared to the shorter service life of prior art scrapers.

[0096] Figures 21 to 24 The prior art HT-type scraper 130 shown is connected to a dedicated suspension arm and mounting assembly 132 of the conveyor belt machine 10 (see...). Figure 21 ).

[0097] Figure 21 and Figure 2 The same features of the same conveyor belt machine 10 shown are identified by the same numbers in the accompanying drawings and the following description.

[0098] The existing HT-type scraper 130 has an HT-type retaining body 134, on which two scraper elements 136 and 138 are fixed.

[0099] like Figures 22 to 24 As shown more clearly, a first scraper element 136, utilizing four tungsten carbide sheets or blades 140, initially cleans the conveyor material adhering to the return side 13 of the belt 11. Meanwhile, a second scraper element 138, also utilizing four tungsten carbide sheets or blades 144 but located on a retaining body 134 further away from the belt 11, physically protects the stud 141 and its nut from damage caused by collisions with conveyor bulk material falling from the top of the belt 11. The falling conveyor bulk material collides with the four tungsten carbide blades 144 of the second scraper element 138, rather than colliding with and damaging the stud 141 and its nut. This protection of the stud 141 and its nut extends the service life of the prior art HT-type scraper 130.

[0100] The prior art HT-type scraper 130 includes two conventional three-layer structures 30 sandwiched between corresponding stepped portions 146, 148 of the retaining body 134 and corresponding tungsten carbide blades 140, 144. For the reasons described above, the tungsten carbide blades 140, 144 are separated end-to-end by expansion joints 150, 152, and the tungsten carbide blades 140, 144 are connected to the retaining body 134 on opposite sides by a brazing process.

[0101] However, this configuration of the prior art scraper 130 requires the two opposing scraper elements 136, 138 to be separated from each other by the upper extension of the retaining body 134. This increases the amount of steel required to construct such a retaining body, thus significantly increasing the cost of manufacturing such a scraper 130. The prior art scraper 130 configuration also requires brazing on opposite sides of the retaining body 134, which increases the complexity and difficulty of the brazing process and further increases the manufacturing cost of such a scraper 130.

[0102] Figures 25 to 27 Another conveyor belt scraper or conveyor belt cleaner tip 160 according to a more specific fourth embodiment of the invention is shown. The scraper 160 is of the HT type, but has an improved HT type retainer body 162, which is preferably made of stainless steel, but may also be made of low carbon steel or other suitable metal or alloy material, on which an improved scraper element 164 with a different structure than that used in the H type scraper 60, P type scraper 90 and R type scraper 110 is fixed.

[0103] like Figure 27 As shown more clearly in the diagram, the scraper element 164 includes: a three-layer structure 166 with a central plane or planar cross-section, used in the brazing process and preferably made of a conventional filler material; a thin planar or planar cross-section backing strip 168 or plate on one side of the three-layer structure 166, preferably made of stainless steel, but may alternatively be made of low-carbon steel or other suitable metal or alloy material; and a single tungsten carbide sheet or blade 170, which provides a scraping edge 171 on one side of the three-layer structure 166 and a physical protective edge 172 for the stud 174 and its nut on the other side of the three-layer structure 166.

[0104] A planar backing strip 168 is connected to a retaining body 162 along at least one of its first surfaces. The planar backing strip 168 is also connected to a single tungsten carbide sheet 170 via a three-layer structure 166 along at least one of its opposite second surfaces.

[0105] In the first step of assembling the scraper 160, a suitable brazing process is used to securely braze the planar three-layer structure 166 between the planar backing strip 168 and the individual tungsten carbide blades 170 to form or assemble the scraper element 164. In this embodiment, an induction brazing process is used to melt the filler material of the three-layer structure 166, allowing it to flow and effectively connect the individual tungsten carbide blades 170 to the retaining body 162. Although induction brazing is used in this embodiment of the invention, other suitable brazing techniques, such as silver brazing, sometimes also called hard brazing, can be used alternatively.

[0106] As is well known to those skilled in the art, in order to form a brazed joint between two metal or metal alloy surfaces, the three-layer structure 166 must include a filler material with a melting point lower than that of the two surfaces being joined. For example, a metallic filler material having two outer strips (or layers) primarily composed of silver with lower concentrations of other common filler metals (such as zinc, nickel, manganese, and optionally cadmium) can be used, coated on a copper core strip. When sufficiently heated by electromagnetic induction, the filler material melts and then flows capillarily upon cooling, bonding the two surfaces together to form a joint.

[0107] Then, in the second step of assembling the scraper 160, the flat-section backing strip 168 of the assembled scraper element 164 is fixed to the flat top surface of the retaining body 162 by a suitable welding process (such as laser welding, or possibly by plasma welding, or by conventional TIG welding or MIG welding) or by a suitable fastening process using mechanical fasteners or other connecting devices.

[0108] In this embodiment, before fixing the assembled scraper element 164 to the retaining body 162 in the second step, induction brazing is used as the first step in assembling the scraper element 164. Furthermore, the use of a backing strip 168 in the induction brazing process results in a significantly lower torsional force on the scraper element 164 (particularly the individual tungsten carbide blades 170 included in the scraper element 164) during shrinkage under the high temperatures applied in the aforementioned induction brazing process compared to the torsional force experienced by scraper elements in prior art scrapers. Without being bound by theory, this is likely primarily due to the use of the backing strip 168 to which the individual tungsten carbide blades 170 are brazed, and that the backing strip is made of the same or similar material (particularly its thermal properties) as the retaining body 162. These features enable the facing surfaces of the backing strip 168 and the retaining body 162 to be joined in a second step by heating (e.g. by welding) at a lower temperature than that used in the prior art, where a backing strip is not used, and multiple tungsten carbide blades are joined to the retaining body via a three-layer structure using a high-temperature brazing process to form or assemble the prior art scraper in a single step.

[0109] The HT-type retaining body 162 has a corrugated surface arrangement 180 that forms a variable protruding wall portion 182. In this embodiment, the variable protruding wall portion 182 extends vertically along its length from a larger mounting wall portion 184 to different height ranges (e.g., Figure 26 as shown in detail).

[0110] Bolts or studs 174 passing through holes in the mounting wall portion 184 connect the scraper 160 to the suspension arm and mounting assembly 132 of the conveyor belt machine 10 (see...). Figure 21 ).

[0111] In this embodiment of the invention, and unlike the retaining bodies 62, 92, 112 of scrapers 60, 90, 110, the retaining body 162 of scraper 160 does not have an L-shaped stepped portion. The flat-section backing strip 168 of the assembled scraper element 164 is flatly positioned on the adjacent top surface of the variable protruding wall portion 182 and the mounting wall portion 184 of the retaining body 162, and welded thereto along a variable path that follows the outer line (or contour) of the wave-shaped surface arrangement 180 of the variable protruding wall portion 182 to form a wave-shaped weld joint 186. Because the path of the wave-shaped weld joint 186 between the retaining body 162 and the scraper element 164 is not linear, the non-linear or variable path of the wave-shaped weld joint 186 significantly extends the service life of scraper 160 compared to the shorter service life of prior art scrapers.

[0112] like Figure 27 As shown, in addition to the wave-shaped welded joint 186, there is also a linear welded joint 188 formed along the exposed joint at the top of the flat section backing strip 168 and the mounting wall portion 184 of the retaining body 162.

[0113] As long as at least some portions of the corrugated surface-shaped weld joint 186 between the scraper element 164 and the variable protruding wall portion 182 have a sufficiently strong bond, the scraper 160 can remain operational, even if prolonged use may cause gradual wear to portions of both the scraper element 164 and the variable protruding wall portion 182, as well as portions of the corrugated surface-shaped weld joint 186 closer to the scraper element 164 than to the mounting wall portion 184.

[0114] The preferred scraper-bearing retainer bodies 62, 92, 112, and 162 of the present invention can be made of any suitable metal or alloy material, as an alternative to stainless steel or low-carbon steel, provided that such material is compatible with the material used to make the backing strip and at least has substantially similar thermal properties (the reasons for which are obvious from the above description). The backing strip can also be made of any suitable metal or alloy material.

[0115] In other suitable embodiments of the invention, the weld joints 84, 186 may take different shapes, forms, and configurations depending on the structure or shape of the protruding wall portion. For example, the protruding wall portion may include one or more holes (of any suitable shape), and a weld joint may be formed along the inner edges of these holes or each inner edge between the backing strip of the assembled scraper element and the protruding wall portion of the retaining body. Furthermore, the outer contour structure (or protruding edge shape) of the protruding wall portion may be a castle-celled arrangement or any other suitable outer contour structure or shape, rather than the serrated arrangement 113 or the wavy surface arrangement 180.

[0116] This invention is applicable to many types of conveyor belt scrapers, not only to the H, R, P and HT types mentioned above, but also to Y, HEL and HMLL type scrapers, or any other suitable scraper type.

[0117] When an L-shaped cross-section backing strip is required instead of a flat cross-section backing strip or other configured backing strips, the scraper of the present invention does not always require the formation of an L-shaped stepped portion in its retaining body. This is because the L-shaped cross-section backing strip itself provides an L-shaped stepped portion when one of the two outer flat sides of the L-shaped cross-section backing strip is fixed to a flat surface area of ​​the mounting wall portion, or to a flat surface area of ​​a protruding wall portion located at the end of the mounting wall portion. For this type of scraper, at least some portions of the weld joint between the scraper element and the selected flat surface area of ​​the wall portion still need to have sufficiently strong bonding to ensure that the scraper remains functional during prolonged use.

[0118] In addition to the advantages described above derived from the present invention, another significant advantage is that only a single tungsten carbide sheet or blade is needed to create an assembled scraper element that substantially extends the length of the retaining body of the scraper, and this helps to significantly save time, labor and cost in manufacturing such a scraper.

[0119] Upon reading the description of the embodiments of the present invention, those skilled in the art will also readily understand that alternative embodiments of the conveyor belt scraper falling within the scope of the present invention may exist. Any prior publications (or information derived therefrom) or any known matters mentioned in this specification are not and should not be construed as an admission or confession, or in any way imply that prior to the filing date of this patent application, such prior publications (or information derived therefrom) or known matters constituted part of the general knowledge of the field of business to which this specification pertains.

Claims

1. A doctor blade for a belt of a conveyor belt machine, the doctor blade comprising: (a) a retaining body made of a first metal or alloy material and having a length, the retaining body being adapted to be connected to a mounting assembly of the conveyor belt machine, and (b) a doctor blade element joined to the retaining body and adapted to scrape from the belt any conveyed material adhering to the belt, the doctor blade element comprising a single tungsten carbide blade having a length that substantially extends the length of the retaining body, the single tungsten carbide blade being joined to a backing strip made of a second metal or alloy material by brazing, the second metal or alloy material having thermal properties that are the same or similar to the first metal or alloy material of the retaining body, the backing strip of the doctor blade element so assembled then being joined to the retaining body such that the single tungsten carbide blade substantially extends the length of the retaining body.

2. The doctor blade of claim 1, wherein the retaining body comprises a variable projection wall portion to which the backing strip of the doctor blade element is joined, wherein the variable projection wall portion extends to different height ranges along its length from a mounting wall portion and a weld joint is formed along a variable path that follows an outer line of the variable projection wall portion.

3. The doctor blade of claim 1, wherein the backing strip is an L-shaped cross-section backing strip.

4. The doctor blade of claim 1, wherein the backing strip is a flat cross-section backing strip.

5. The doctor blade of claim 2, wherein the variable projection wall portion is a sawtooth arrangement.

6. The doctor blade of claim 5, wherein the weld joint is a sawtooth-shaped weld joint.

7. The doctor blade of claim 2, wherein the variable projection wall portion is a wave surface arrangement.

8. The doctor blade of claim 7, wherein the weld joint is a wave surface shaped weld joint.

9. The doctor blade of claim 1, wherein the first metal or alloy material is selected from stainless steel or mild steel.

10. The doctor blade of claim 1, wherein the second metal or alloy material is selected from stainless steel or mild steel.

11. The doctor blade of claim 1, wherein the backing strip is joined to the retaining body by welding.

12. The doctor blade of claim 1, wherein the single tungsten carbide blade is joined to the backing strip by induction brazing.

13. The doctor blade of claim 1, wherein a metal filler material is used for the brazing.

14. The doctor blade of claim 13, wherein the metal filler material is a silver-based filler material.

15. The doctor blade of claim 14, wherein the silver-based filler material is in the form of a three-layer structure.

16. A method of assembling a doctor blade for a belt of a conveyor belt machine, the method comprising the steps of: (a) providing a retaining body made of a first metal or alloy material and having a length, (b) providing a single tungsten carbide blade having a length that substantially extends the length of the retaining body, (c) providing a backing strip made of a second metal or alloy material having thermal properties that are the same or similar to the first metal or alloy material of the retention body, (d) brazing the single tungsten carbide blade to the backing strip to form an assembled doctor blade element, and (e) joining the assembled doctor blade element to the retention body such that the single tungsten carbide blade extends substantially the length of the retention body.

17. The method of claim 16, wherein the single tungsten carbide blade is brazed to the backing strip by induction brazing.

18. The method of claim 16, wherein the assembled doctor blade element is joined to the retention body by welding.

Images