DE102016104334B4 - Mixing tool manufacturing process - Google Patents

Abstract

A mixing tool manufacturing method, comprising the following steps: - providing a metallic core (6); - attaching at least one cemented carbide element (5) to the metal core (6); - placing the metal core (6) with the cemented carbide element (5) in a mold; - filling the mold with a Kunststoffgießmaterial; and curing the Kunststoffgießmaterials to a metal core (6) surrounding the plastic sheath (7).

Description

The invention relates to a method for producing a mixing tool.

Such mixing tools are used to mix building materials, in particular coarse-grained material, for example cement, mortar or concrete. For this purpose, the building material is filled in a mixing container in which the mixing tool, in particular designed as a mixing blade, is rotatably mounted on a mixing arm relative to the mixing container. In this case, either the mixing container can be fixed and the mixing arm can be rotatably mounted, or vice versa.

Due to the contact with the granular building material, it can quickly lead to wear on the mixing tool to minor or major damage to its surface. The mixing tool must then be repaired or even replaced. To increase the durability of the mixing tool, they are often partially or completely covered with a plastic, for example by means of polyurethane. When used in the mixing apparatus, the mixing tool serves not only to mix the building material in the mixing tank, but also to scrape or strip off building material fixed to tank walls of the mixing tank. In this case, in particular scraping along the container wall scraping edge of the mixing tool is extremely stressed. The plastic is slightly damaged and leads to a rapid wear of the mixing tool.

DE 198 56 622 A1 discloses a mixing blade of a stiffening core and a plastic layer enclosing it. In DE 18 83 029 U is described an agitator blade with a steel vane core, which is embedded in a rubber jacket. Another mixer blade is in DE 33 41 830 A1 disclosed. This consists of a carrier plate and attached replaceable wear pads.

It is an object of the invention to provide a method for producing a mixing tool with a longer shelf life.

The object is achieved according to the invention by a mixing tool manufacturing method having the features of claim 1. Advantageous developments of the invention are listed in the subclaims.

The invention is based on the idea to form the scraping edge made of hard metal in a plastic mixing tool. That is, one or more cemented carbide elements are attached to the mixing tool that provide or form the scraping edge. The hard metal element is preferably formed from sintered hard metal, in particular from sintered carbide hard metal. Preferably, it is made as a composite of tungsten carbide and the binder Cobald.

The scraping edge is arranged on a stripping section of the mixing tool and serves to strip mix from the wall of the mixing container. In order to fix the mixing tool on the mixing arm, it has a mounting portion which is rigidly or elastically connected to the stripping section. Fastening portion and stripping together have a metallic core, which is surrounded by a plastic sheath.

The mixing tool is made by first connecting the metallic core to the cemented carbide element. Subsequently, the entire arrangement of core and hard metal element is introduced into a mold, which is then filled with a Kunststoffgießmaterial. The plastic casting material is a precursor of the plastic from which the plastic jacket is formed. In particular, it may be a mixture of two or more components, which then solidify to the desired plastic. Only after the curing of the Kunststoffgießmaterials so the finished plastic jacket with the desired hardness. The curing process can take a few minutes or more. Furthermore, the curing process may occur at ambient temperature or under heat.

Subsequently, the finished mixing tool is removed from the mold and optionally reworked. For example, it may be necessary to remove plastic covering the hard metal element (s). The arrangement of core and hard metal element is preferably arranged in the casting mold before filling with the plastic casting material in such a way that when the casting mold is loaded with the plastic casting material, the hard metal element or at least the scraping edge is essentially not covered. This can be achieved, in particular, by the fact that the scraping edge bears against or touches a casting mold wall of the casting mold.

In a preferred embodiment, provision is made for a first core section assigned to the fastening section to be rigidly connected to a second core section assigned to the stripping section. The connection is preferably a welded connection between the two core sections. Alternatively, the first and second core portions may also be integrally formed, for example, manufactured as a single metal casting. Preferably, however, the core is made of a plurality of metallic elements assembled, which are welded together. The metallic core can in particular be made of steel, for example of tool steel, or have metallic elements made of steel or tool steel.

In an advantageous development, it is provided that a first core section assigned to the fastening section is elastically and / or hingedly connected to a second core section assigned to the wiper section. That the first core portion is associated with the attachment portion means that the attachment portion is formed of the first core portion and the part of the plastic shell surrounding or covering the first core portion. The same applies to the stripping section and the second core section. An elastic and / or articulated connection between the two core sections has the consequence that, due to the plastic jacket surrounding both core sections, the connection between the fastening section and the wiper section is also deformable and preferably elastic. This means that the stripping section is movable relative to the fastening section, preferably elastically movable. Since the wiping edge is formed on the wiper portion, this has the consequence that the wiper can yield when in contact with obstacles, such as dents or smaller bumps in the wall of the mixing container, without risking damage to the mixing tool, for example due to splintering of the cemented carbide element.

In any event, the first core portion has one or more fasteners to secure the mixing tool to the mixing arm. The fastening element may for this purpose for example have an opening, a profile with a groove, for example a C-profile, and / or a threaded element. Furthermore, the plastic sheath is preferably formed in one case from a cast, so in particular has no seams.

The articulated or elastic connection between the two core sections can be formed exclusively by the plastic jacket. Preferably, however, a mechanical joint is additionally or alternatively formed between the two core sections, which also exists without the plastic jacket. In an expedient embodiment, it is provided that one of the two core sections has an extension, in particular a pin-shaped or tongue-shaped extension, which protrudes into a recess in the other core section. In particular, the extension may be formed on the first core portion. Preferably, two or more such extensions are formed on the one core section which are inserted into two or more openings of the other core section during manufacture of the mixing tool. Subsequently, a termination member is soldered or welded to ends of the extensions to establish the hinged connection between the core portions.

In the production of a mixing tool with an articulated or elastic connection between the two core sections, the two core sections are thus movable relative to one another, preferably pivotable relative to one another about an oscillating axis. In this case, it is advantageous to fix the two core sections against each other before or during the placing in the mold. This is preferably done by the mold is formed so that the two core sections can not move against each other therein.

According to a preferred embodiment, it is provided that the hard metal element is welded or soldered to the metallic core. This is preferably done by brazing. In any case, preferably a plurality of cemented carbide elements are strung together along the scraping edge. The hard metal elements are preferably sickle-shaped. At an end face or end edge of the mixing tool and other hard metal elements may be arranged to protect the mixing tool there from wear.

Preferably, it is provided that the metallic core is covered or surrounded by the plastic jacket and / or by the hard metal element to more than 70%, 80%, 85%, 90%, 95% or substantially completely. These percentages relate in particular to the surface of the metallic core. Preferably, the metallic core is substantially completely covered except for end faces and fastening elements, optionally having exposed end faces perpendicular to the wiping edge. This is about protecting the metallic core from wear by means of the plastic sheath or hard metal element.

In a preferred embodiment, it is provided that the metallic core is divided into a plurality of segments attached to one another. The metallic core is preferably segmented along the scraping edge. The segments of the metallic core can in particular be designed essentially identical. These segments may also be secured to each other by means of joining elements, for example by means of welding, prior to the manufacture of the plastic sheath.

Preferably, the hard metal element or the hard metal elements is embedded in the plastic jacket. This means that one, two or more outer surfaces of the cemented carbide element is formed in alignment with a mantle surface of the plastic sheath is / are.

In an advantageous development, it is provided that the plastic sheath is formed from polyurethane. Preferably, the polyurethane has a Shore hardness in a range between 65 and 90 Shore A.

• 1 ein Segment eines Mischwerkzeugs;
• 2 ein weiteres Segment des aus der 2 Mischwerkzeugs;
• 3 eine Querschnittsansicht der Segmentes aus der 2;
• 4 eine Querschnittsansicht der Segmentes aus der 1;
• 5 eine Seitenansicht des metallischen Kerns des Segmentes aus der 1, mit hieran befestigten Hartmetallelementen;
• 6 ein nicht segmentiertes Mischwerkzeug;
• 7 eine Seitenansicht eines gelenkig aufgebauten metallischen Kerns, mit hieran befestigten Hartmetallelementen;
• 8 eine perspektivische Ansicht des Kerns aus der 7 mit Kunststoffmantel; und
• 9 eine Explosionszeichnung der Anordnung aus der 7.

The invention will be explained below with reference to embodiments with reference to the figures. Hereby show:

• 1 a segment of a mixing tool;
• 2 another segment of the out of the 2 Mixing tool;
• 3 a cross-sectional view of the segment of the 2 ;
• 4 a cross-sectional view of the segment of the 1 ;
• 5 a side view of the metallic core of the segment of the 1 with cemented carbide elements attached thereto;
• 6 a non-segmented mixing tool;
• 7 a side view of a hinged metallic core, with attached thereto cemented carbide elements;
• 8th a perspective view of the core of the 7 with plastic sheath; and
• 9 an exploded view of the arrangement of the 7 ,

In the 1 a segment of a mixing tool is shown schematically. It has a fastening section 2 and a scraping section 4 on, with the subdivision in attachment section 2 and stripping section 4 not strictly along a dividing line. The attachment section 2 serves to secure the mixing tool to a mixing arm while the scraping section 4 a scraping edge 41 has, by means of which mix from a wall of a mixing container (not shown in the figures) can be scraped off or scraped off. The wiper edge 41 is by means of hard metal elements 5 formed along the mixing tool in the direction of the wiping edge 41 strung together.

On a frontal surface 11 of the mixing tool segment, it can be seen that the segment consists of a metallic core 6 and one this core 6 surrounding plastic jacket 7 made of polyurethane. The metallic core 6 tool metal is composed of several parts that are welded together. These include a first core section 62 , which is designed as a C-profile and thus has a groove. This groove forms a fastening element with which the attachment of the mixing tool takes place on the mixing arm. Further, the core points 6 a two core section 64 on which the hard metal elements 5 are attached by brazing. Other parts of the metallic core 6 also form a connector 63 which is the first core section 62 rigid with the second core section 64 connects, and a stiffener 65 , which at the first core section 62 is attached and serves that the plastic sheath 7 keeps its shape stable here.

At the in 1 The segment shown may be an end segment or a middle segment of the mixing tool. In certain embodiments, the entire mixing tool can also only one segment as in 1 represented exist. Preferably, the mixing tool in addition to the in 1 still shown in the segment 2 represented segment on which, however, can also serve as an independent mixing tool. It points beside the along the scraper edge 41 arranged hard metal elements 5 two more carbide elements 51 on, at the frontal area 11 are arranged, and there protect a front edge of the mixing tool against wear.

In the 3 is a cross-sectional view of the segment from the 2 parallel to the face 11 shown. Here it becomes visible that the further hard metal elements 51 on support elements 66 soldered as part of the metallic core 6 also with the first core section 62 and the second core section 64 are secured by welding.

The 4 shows a cross section of the segment of the 1 and / or also of the segment from the 2 but farther away from the face 11 at which the other carbide elements 51 are attached. Therefore, the other carbide elements 51 not visible here. Instead, joining elements 8th drawn, which serve to assemble several such segments to a mixing tool. The joining elements 8th are with the metallic cores 6 two or more mixing tool segments welded before the plastic jacket 7 is formed around it.

In the 4 is clearly visible on the cemented carbide element 5 both a front surface 12 , as well as a lower surface 13 with associated surfaces of the plastic sheath 7 finish flush or go into this. This will ensure that the mixing tool has a flat front surface 12 and a flat lower surface 13 having no recesses or elevations, which could be attack surfaces for wear.

In the 5 is the metallic core 6 of the segment from the 1 with the soldered carbide element 5 shown. For the subsequent production of the plastic sheath 7 , the arrangement of the 5 preferably introduced in a direction perpendicular to the image plane in a mold, which in cross-section the shape of the plastic sheath of the 4 having. Subsequently, the mold is charged or filled with a Kunststoffgießmaterial. When the plastic casting material hardens, the plastic sheath is formed 7 ,

The 6 shows a mixing tool, which is not made in segmental construction. Here are just the plastic jacket 7 and the cemented carbide elements 5 visible, which is the wiper edge 41 form. The metallic core 6 which is also present in this embodiment and on which the hard metal elements 5 soldered is not visible, as it is completely covered by plastic 7 and the cemented carbide elements 5 is covered or surrounded. In addition one sees in the 6 fasteners 621 in the form of holes, which serve to attach the mixing tool to a mixing arm.

Another embodiment for a mixing tool will now be described with reference to FIG 7 . 8th and 9 explained. This is a mixing tool, which is also developed in the form of a segment, with one or more other similar segments to a mixing tool with a larger scraping edge 41 can be joined together. Unlike in the 1 to 5 shown mixing tool segments, the mixing tool from the 7 to 9 an elastic connection between the attachment portion 2 and the stripping section 4 on. This is achieved by the fact that the metallic core 6 a joint between the first core section 62 and the second core section 64 forms. If the metallic core 6 then with a plastic jacket 7 is provided, then creates the elastic connection.

In the 7 alone becomes the metallic core 6 with one at the second core section 64 soldered carbide element 5 shown in a side view. The 8th shows the one with the plastic core 7 polyurethane surrounding metallic core 6 from the 7 , And the 9 shows an exploded view of each in the 7 represented parts.

Unlike the blending tool with rigid connection between the first core section 62 and the second core section 64 , In the present embodiment is the connecting element 63 by a first hinge element 631 and a second hinge element 632 replaced, which intervene in each other. These are on the first joint element 631 tongue-shaped joint element extensions 634 formed in the Gelenkelementausnehmung 635 of the second joint element 632 to grab. After insertion of the articular processes 634 in the Gelenkelementausnehmung 635 , becomes a pin-shaped end element 633 at the ends of the articulation element extensions 634 welded to the second hinge element 632 to keep. As a result, the two joint elements 631 . 632 movable against each other to a certain degree. Depending on the strength and elasticity of the plastic sheath 7 In the case of the finished mixing tool, this leads to a more or less elastic mobility between the first core section designed as a fastening element 62 and the cemented carbide elements 5 so that the mixing tool is more or less yielding when touching a survey on the mixing vessel wall at the wiper edge.

In a modified embodiment, the pin-shaped closing element is missing 633 and / or the first joint element 631 , At least in this embodiment, the second hinge element 632 without the plastic jacket 7 not at the first core section 62 coupled. In this case, the second joint element 632 So only by means of the plastic sheath 7 with the first core section 62 connected.

The other elements of the mixing tool according to the 7 to 9 correspond to the elements of the mixing tool according to the 7 to 91 to 5 if they bear the same reference numbers. In addition, also in the mixing tool according to the 7 to 9 further carbide elements 51 at the frontal area 11 a segment be provided.

LIST OF REFERENCE NUMBERS

11 face 12 front surface 13 undersurface 2 attachment section 4 stripping 41 stripping 5 Carbide element 51 another carbide element 6 metallic core 62 first core section 621 fastener 63 joint 631 first joint element 632 second joint element 633 Exit element 634 Joint element extension 635 Joint element recess 64 two core section 65 stiffener 66 support element 7 Plastic sheath 8th joining element

Claims (9)

Blending tool manufacturing method comprising the following steps: - Providing a metallic core (6); - Attaching at least one hard metal element (5) to the metallic core (6); - placing the metallic core (6) with the hard metal element (5) in a mold; - filling the mold with a Kunststoffgießmaterial; and - Curing the Kunststoffgießmaterials to a metallic core (6) surrounding the plastic sheath (7). Mixing tool manufacturing method Claim 1 characterized in that by means of said steps a mixing tool, in particular a mixing blade, is produced with a fastening section (2) for attachment to a mixing arm of a mixing device and a stripping section (4) connected to the fastening section (2), which has a scraping edge ( 41) for stripping mixed material from a wall of a mixing container of the mixing device, wherein the fastening portion (2) and the stripping portion (4) of the metallic core (6) are formed, which is surrounded with the plastic jacket (7) and wherein the scraping edge (41) is formed by at least the hard metal element (5). Mixing tool manufacturing method Claim 2 characterized in that a first core portion (62) associated with the mounting portion (2) is rigidly connected to a second core portion (64) associated with the wiper portion (4). Mixing tool manufacturing method Claim 2 characterized in that a first core portion (62) associated with the mounting portion (2) is resiliently and / or hingedly connected to a second core portion (64) associated with the wiper portion (4). Mixing tool manufacturing method Claim 2 , characterized in that one of the two core sections (62; 64) has a pin-shaped or tongue-shaped extension (634) which projects into a recess (635) in the other core section (64; 62). Mixing tool manufacturing method according to one of the preceding claims, characterized in that the hard metal element (5) is welded or soldered to the metallic core (6). Mixing tool manufacturing method according to one of the preceding claims, characterized in that the metallic core (6) through the plastic jacket (7) and / or through the hard metal element (5) to more than 70%, 80%, 85%, 90%, 95% or is substantially completely covered. Mixing tool manufacturing method according to one of the preceding claims, characterized in that the metallic core (6) is subdivided into several segments attached to one another. Mixing tool manufacturing method according to one of the preceding claims, characterized in that the plastic jacket (7) is formed from polyurethane.

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