Mixing shaft

Abstract

The invention relates to a mixing shaft having a tool holder rotatable about a tool axis and at least one mixing blade, the tool holder comprising at least one recess in which a mixing blade portion of the at least one mixing blade is received, a clamping member inserted into the recess is configured to secure the mixing blade portion in the recess wherein the recess comprises a first recess portion and a second recess portion wherein the mixing blade portion is arranged in the first recess portion and the clamping member is at least partially arranged in the second recess portion, characterized in that the clamping member is configured to clamp the mixing blade portion in the second recess portion. The first recess portion and the second recess portion are arranged adjacently in a plane extending perpendicular to the tool axis.

Description

Technical Field

[0001] The invention relates to a mixing shaft having a tool holder rotatable about a tool axis and at least one mixing blade, wherein the tool holder comprises at least one recess in which a mixing blade portion of at least one mixing blade is received. In order to fix the mixing blade portion in the recess, a clamping member is configured to be inserted into the recess. For this purpose, the recess is divided into a first recess portion and a second recess portion, wherein the mixing blade portion is arranged in the first recess portion and the clamping member is at least partially arranged in the second recess portion. Background Art

[0002] Mixing shafts of the type described above are used in various mixers known in the prior art. The mixing shaft is therefore usually arranged approximately perpendicular to the bottom of the mixing container therein. In order to mix the materials to be mixed in the mixer, the tool holder of the mixing shaft usually comprises a plurality of mixing blades which are arranged one after the other in a plurality of planes along the tool axis and extend radially outwards from the tool axis of the mixing shaft.

[0003] If the mixing shaft rotates about the tool axis during operation of the mixer, the material to be mixed flows through the mixing blades, which are therefore subject to wear and must be replaced regularly. It has been shown that mixing blades which are covered by a higher layer of material to be mixed, i.e. mixing blades arranged close to the bottom of the container, wear much faster than mixing blades which are arranged close to the surface of the material to be mixed, i.e. mixing blades which are far from the bottom of the mixing container.

[0004] Therefore, it is already known from the prior art to be able to remove the mixing blades individually from the tool holder and to replace them with new mixing blades. The object is to replace the mixing blades as quickly and conveniently as possible.

[0005] For this purpose, it is known from the prior art to clamp the mixing blade in a recess of the tool holder with a clamping device. For example, a corresponding clamping device is known from EP 3 439 774 B1. In this case, when viewed in the direction of the tool axis, a first recess portion is arranged above a second recess portion, in which a part of the mixing blade is located, and in which a clamping member for fixing the mixing blade is inserted. The clamping member consists of several parts and is fixed in the recess by means of several screws.

[0006] However, such complex clamping systems can only be mounted and disassembled with great effort. Furthermore, the clamping members are sometimes difficult to access due to their arrangement below or above the mixing blades and are proportionally exposed to high wear caused by the material to be mixed flowing through. Finally, with such clamping systems, the mixing blades must be adjusted since the mixing blades are closest to the top of the container and, in the best case, are guided as close as possible to the bottom of the container. Summary of the invention

[0007] It is therefore an object of the present invention to provide a mixing shaft with a tool holder which allows particularly simple replacement of mixing blades.

[0008] The object of the invention is achieved by a mixing shaft of the type mentioned at the outset, wherein the first recess section and the second recess section are arranged adjacent to each other in a plane extending perpendicularly to the tool axis.

[0009] In other words, the clamping members are arranged in one plane with the mixing blade portion when viewed in the direction of the tool axis, rather than being arranged sequentially along the tool axis as in prior art clamping systems.

[0010] This offers the advantage that the clamping member is easily accessible and is not arranged below the mixing blade. Thus, the tool required for replacement can be inserted without colliding with the mixing blade.

[0011] Furthermore, only one recess needs to be provided in the tool holder in the circumferential direction, rather than two recesses arranged one above the other. This simplifies the removal of the mixing blade from the tool holder and the assembly of the mixing blade in the tool holder. Overall, these advantages enable a more efficient replacement of the mixing blade compared to the mounting options known from the prior art.

[0012] In one embodiment, the mixing shaft is configured to rotate about the tool axis in a rotational direction, wherein the second recess portion is arranged downstream of the first recess portion in the rotational direction.

[0013] This has the advantage that the clamping element is located in the flow shadow of the mixing blade and is thus effectively protected from wear. Due to the flow over the mixing blade, there is no or only a very slight incident flow through the material to be mixed.

[0014] In another embodiment, the clamping member comprises an anti-corrosion coating, wherein preferably the coating is a cadmium or phosphate coating. This measure also prolongs the service life of the clamping member. In addition, the removal of the clamping member is simplified, since even after long-term installation and operation of the mixer, adhesion of the clamping member is reduced.

[0015] In another embodiment, the clamping member is fixed to the tool holder in the recess by means of a screw, wherein the screw preferably extends through a through hole of the clamping member into a threaded hole arranged on the rear wall of the recess in the tool holder. Preferably, the clamping member is connected to the tool holder radially with respect to the tool axis. Thus, the clamping system according to the invention is fastened by only a single screw, which allows a quick replacement of the mixing blade.

[0016] In another embodiment, the release device is configured to release the clamping member from the recess.

[0017] Such a release device can be, for example, a pressure screw which engages with a corresponding forcing-off thread implemented in a through hole of the clamping member. It goes without saying that the forcing-off thread and the pressure screw comprise a larger diameter than the screw suitable for fixing the clamping member in the recess, so that the fixing screw is guided through the forcing-off thread for fixing the clamping member in the recess. As soon as the fastening screw for removing the mixing blade is removed, the pressure screw is screwed into the forcing-off thread and exerts a force on the rear wall of the recess, so that the clamping member is released from the recess.

[0018] Alternatively, an ejector device can be fastened in a through hole of the clamping member as a release device, with which the clamping member is ejected from the recess.

[0019] However, these solutions have the disadvantage that impurities can accumulate in the extruded thread, so that the thread has to be recut regularly, which requires an additional work step.

[0020] Thus, preferably, in one embodiment, the release device is connected to a portion of the screw in a form-fitting or integral manner, wherein the release device is arranged between the clamping member and the rear wall of the recess. Thus, the one-piece connection is preferably provided by a welded or adhesive connection.

[0021] By providing a release device for tightening the clamping member on the screw, an additional work step of removing the clamping member, for example by means of a pressure screw or an ejection device, is eliminated. Due to the release device, unscrewing the screw leads to an immediate release of the clamping member in the recess.

[0022] In another embodiment, the release device is shaped as a disk, wherein preferably the outer circumferential surface of the disk is shaped as a circle and has no sharp edges. This ensures that the release device can also be moved if the material to be mixed has penetrated between the release device and the inner part of the recess. This counteracts interference of the release device.

[0023] In particular, in another embodiment, the release device is arranged at a distance from the clamping member to prevent jamming with the screw.

[0024] In another embodiment, a seal is provided, which is preferably made of plastic material, particularly preferably made of polyurethane, which is arranged on a portion of the screw between the release device and the rear wall of the recess, so that the threaded opening in the rear wall of the recess is sealed by the screw and the seal in the mounted state of the clamping member. The seal thus protects the threaded opening in the recess of the tool holder from contamination by the permeable material to be mixed, which in turn simplifies the removal of the clamping member and thereby the removal of the mixing blade.

[0025] In a preferred embodiment, the clamping member is formed as a one-piece member. Thus, in order to replace the mixing blade, several parts of the clamping member do not need to be released, thereby allowing a faster replacement. A one-piece connection is understood to be a connection that cannot be disconnected non-destructively. For example, the clamping member can be manufactured in a single casting, or welded together from several parts.

[0026] However, it goes without saying that according to the invention the clamping element can also be designed in two or more parts.

[0027] In another embodiment, the clamping member and the mixing blade part and / or the mixing blade part and the tool holder are configured in such a way that the clamping member and the mixing blade part and / or the mixing blade part and the tool holder form a form-fitting connection in the recess. This has the advantage that the mixing blade part is not only force-locked in the recess by means of the clamping member, but the form-fitting connection ensures that the mixing blade part cannot be removed from the recess without removing the clamping member. Therefore, the clamping member mechanically hinders the mixing blade part. Alternatively or additionally, the mixing blade part is connected to the tool holder in a form-fitting manner so that this connection also contributes to the safe fixing of the mixing blade.

[0028] The form-fit connection between the mixing blade part on the one hand and the clamping member or tool holder on the other hand is preferably provided by a pin connection. It goes without saying that, alternatively, a triangular connection, an L-shaped connection or other connection geometries can also be used for the form-fit connection.

[0029] In particular, in another embodiment, the clamping member is arranged between the mixing blade portion and the side wall of the second recess portion opposite the mixing blade portion, wherein the clamping member is supported by the mixing blade portion and the side wall, wherein the clamping member and the mixing blade portion and / or the side wall both comprise mutually corresponding wedge surfaces. In the present invention, a wedge surface is understood to be a surface comprising a wedge-shaped geometry in a plane perpendicular to the tool axis. The advantage of the wedge surface is that the mixing blade portion is not only frictionally held by clamping in the recess, but there is also a form fit between the mixing blade portion and the clamping member.

[0030] If the clamping element has a multi-part design, mutually corresponding wedge surfaces can additionally be realized between the individual parts of the clamping element.

[0031] In a further embodiment, the clamping member comprises a lubrication device, wherein the lubrication device comprises a receptacle for a lubricant and a lubrication channel by means of which the lubricant can be introduced from the receptacle into the recess. By means of the lubrication device, the recess can be protected with grease or another filling medium against penetration of material to be mixed or water, which acts on the mixing shaft, for example during operation of the mixer or during pressure cleaning of the mixer.

[0032] Specifically, in one embodiment, the clamping member includes a first side portion and a second side portion arranged one after another in the direction of the tool axis. Here, the first portion of the lubrication channel is formed as a recess, preferably as a groove, on the first side portion and / or the second side portion of the clamping member, and the second portion of the lubrication channel provides a connection between the receiving portion and the first portion of the lubrication channel. In other words, this arrangement transports lubricant from the receiving portion to the contact surface of the clamping member with the recess, i.e. the first side portion and / or the second side portion. Therefore, it goes without saying that in one embodiment, the first portion includes at least two sub-portions, wherein one sub-portion is arranged on the first side portion and the other sub-portion is arranged on the second side portion.

[0033] In another embodiment, the clamping member comprises an outer part and an inner part, wherein the outer part of the clamping member is farther from the tool axis than the inner part, wherein the lubrication channel is arranged in the outer part of the clamping member so that only the outer part of the clamping member and the corresponding part of the recess are supplied with lubricant. Preferably, the outer part comprises a dimension in a radial direction relative to the tool axis, which is at most as large as the dimension of the inner part in the radial direction. Specifically, in another embodiment, a first part of the lubrication channel extends from a first lateral surface of the clamping member in contact with the mixing blade portion in the recess to a second lateral surface of the clamping member opposite to the first lateral surface. This results in the lubricant being effectively distributed in the entire expansion portion of the clamping member in the recess in a circumferential direction.

[0034] The advantage of arranging the lubrication channel in the outer section of the clamping member is that, although the lubricant achieves a lubricating effect on the outside, the inner section of the clamping member is only affected by a small amount of lubricant, or is not affected by the lubricant at all, and thus does not affect the threaded connection between the clamping member and the tool holder. At the same time, arranging the first lubrication channel section in the outer section of the clamping member according to the present invention can also save lubricant.

[0035] In another embodiment, at least one protective element is provided, which is arranged in the second recess portion and comprises a greater distance from the tool axis than the clamping member, so that the clamping member is covered, wherein the protective element at least partially, preferably completely closes the second recess. It goes without saying that a plurality of protective elements can also be provided, for example covering individual holes in the through-hole of the clamping member, such as the lubricant receiving part or the screw head. Thus, the protective element additionally protects the clamping member, in particular the screw head and the lubricant receiving part, from the penetration of moisture or dust by the material to be mixed or the cleaning fluid, thereby extending the service life of the clamping member and its fastening device. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Further advantages, features and possible applications will become clear from the following description of preferred embodiments and the related drawings. Similar components are marked with the same reference numerals.

[0037] Figure 1 A perspective view of an embodiment of a mixing shaft according to the invention is shown.

[0038] Figure 2 Shows Figure 1 A partial cross-sectional view of the mixing axis perpendicular to the tool axis is shown in FIG.

[0039] Figure 3 A further embodiment of a mixing shaft according to the invention is shown in a partial longitudinal section parallel to the tool axis.

[0040] Figure 4 Shows Figure 1 A cross-sectional perspective view of the mixing shaft is shown in FIG. DETAILED DESCRIPTION

[0041] The mixing shaft 1 shown in the figure comprises a tool holder 20 rotatable about a tool axis 100 and a plurality of mixing blades 30. In the tool holder 20, a recess 21 is provided, in which a mixing blade portion 31 of the mixing blade 30 is arranged together with a clamping member 40. The clamping member 40 is used to fix the mixing blade portion 31 in the recess 21.

[0042] Especially in Figure 2 and Figure 3 The detailed structure of fixing the mixing blade part by means of the clamping member 40 is shown in FIG.

[0043] If you can Figure 2 As can be seen, the recess 21 is composed of a first recess portion 21a and a second recess portion 21b. In the first recess portion 21a, the mixing blade portion 31 of the mixing blade 30 is received. In the second recess portion 21b, a clamping member 40 is arranged. Figure 2It can be seen that the clamping member 40 and the mixing blade portion 31 are arranged in a plane extending perpendicularly to the tool axis 100 .

[0044] The clamping member 40 is force-fitted in the second recess portion 21 b by means of a screw 41. For this purpose, the screw 41 passes through a through hole 42 of the clamping member 40 and is screwed into a threaded hole 22 arranged in the rear wall 23 of the recess 21.

[0045] When the clamping member 40 is disposed and fixed in the second recess portion 21 b , the clamping member 40 is disposed between the mixing blade portion 31 and the side wall 24 of the recess 21 so as to clamp the mixing blade portion 31 in the first recess portion 21 a , thereby firmly holding the mixing blade 30 in the tool holder 20 .

[0046] In order to additionally fix the mixing blade section 31 in the first recess section 21 a , a pin 80 is additionally provided in order to form a positive connection between the tool holder 20 and the mixing blade section 31 .

[0047] when Figure 1 When the mixing shaft is rotated counterclockwise as shown, the second recessed portion 21b is located downstream of the first recessed portion 21a in the direction of rotation. As a result, the second recessed portion 21b is located in the flow cover of the mixing blade 30, so that the clamping member 40 is exposed to less wear caused by the flow of the material to be mixed. This in turn increases the service life of the clamping member 40.

[0048] However, since the mixing blades 30 are also subject to wear due to the material to be mixed flowing therethrough, which wear also varies depending on the position of the mixing blades 30 along the tool axis 100, the mixing blades 30 must be replaced individually. In order to remove the mixing blades 30 from the tool holder 20, the clamping member 40 must be removed.

[0049] In order to release the clamping member 40 from the second recessed portion 21b, thereby replacing the mixing blade 30, the screw 41 includes Figure 3 A release device 50 is shown which is integrally connected to the screw 41 and is arranged between the clamping member 40 and the rear wall 23 of the recess 21 .

[0050] In particular, the release device 50 is arranged as an annular washer on the threaded section of the screw 41 so that there is a distance between the release device 50 and the clamping member 40 to prevent interference of the screw 41 with the clamping member 40 on the one hand and with any material to be mixed that may have penetrated on the other hand.

[0051] If the screw 41 is unscrewed from the threaded opening 22 of the rear wall 23 of the recess 21 , this results in the clamping member 40 being released, thereby eliminating the need for an additional operating step of removing the clamping member 40 from the recess 21 .

[0052] In order to protect the threaded opening 22 of the recess 21 from contamination by the material to be mixed, a seal 60 is provided, which is arranged between the release device 50 and the rear wall 23 of the recess 21 and covers the threaded opening 22 together with the screw 41 and the release device 50. The seal 60 is also formed as an annular disk and is made, for example, of polyurethane or another sealing material.

[0053] In order to additionally seal the recess 21 towards the material to be mixed, the clamping member 40 also comprises a lubricating device, which in particular Figure 4 The lubricating device is composed of a receiving portion 43 for lubricant and a lubricating channel, and the lubricating channel is composed of a first section 44a and a second section 44b.

[0054] Thus, the clamping member 40 is configured with a first side 40a and a second side 40b, which are arranged one behind the other in the direction of the tool axis 100. The first section 44a of the lubrication channel is formed as a recess on the first side 40a and the second side 40b of the clamping member (see also Figure 3 The second section 44b of the lubrication channel forms a connection between the lubricant receiving portion 43 and the first section 44a of the lubrication channel. The first section 44a of the lubrication channel can also be continued, if necessary, in particular for sealing purposes, onto a lateral surface of the clamping member 40 extending parallel to the tool axis.

[0055] If you can Figure 4 It can be seen in particular that the lubrication channel is arranged in an outer section of the clamping member 40, which is farther from the tool axis 100 than the inner part of the clamping member 40. As a result, the size of the outer section of the clamping member 40 in the radial direction relative to the tool axis 100 is equal to the size of the inner section in the radial direction. This means that only the outer section of the clamping member 40 and the corresponding section of the recess 21 are supplied with lubricant, thereby saving lubricant. At the same time, the lubrication of the clamping member 40 results in the sealing of the second recess section 21b from external influences. These influences include in particular the inflow of the material to be mixed, but also influences acting on the mixing shaft, for example during high-pressure cleaning of the latter.

[0056] Furthermore, the screw 41 fixing the clamping member 40 in the second recessed portion 21 b is also effectively protected against external influences, so that even after a long service life of the mixing shaft 1 and the mixing blade 30 , the clamping member 40 can be loosened in a simple manner and can be replaced particularly easily.

[0057] Finally, a protective element 70 is also provided which is likewise arranged in the second recess portion 21b and comprises a further distance from the tool axis 100 than the clamping member 40. The protective element 70 is configured in such a way that it covers the radially outer side of the clamping member 40 and additionally protects the latter from external influences.

[0058] Alternatively, the protective element 70 can also be arranged in the radially outer region of the clamping member 40, covering only the lubricant receiving portion 43 and the through-opening 42, for example in the form of one or more plugs (see Figure 2 ).

[0059] Reference numerals list

[0060] 1 Mixing axis

[0061] 20 Tool holder

[0062] 21 recess

[0063] 21a First concave portion

[0064] 21b Second concave portion

[0065] 22 thread opening

[0066] 23 Back wall

[0067] 24 Sidewall

[0068] 30 Mixing blades

[0069] 31 Mixing blade part

[0070] 40 Clamping member

[0071] 40a First side portion of the clamping member

[0072] 40b Second side portion of the clamping member

[0073] 41 screw

[0074] 42 through holes

[0075] 43 Lubricant channel

[0076] 44a First section of the lubricant channel

[0077] 44b Second section of lubricant channel

[0078] 50 Release device

[0079] 60 Seals

[0080] 70 protection elements

[0081] 80 pins

[0082] 100 tool axis

Claims

1. A mixing shaft (1), comprising a tool holder (20) rotatable about a tool axis (100) and at least one mixing blade (30), wherein: The tool holder (20) comprises at least one recess (21) in which a mixing blade portion (31) of the at least one mixing blade (30) is received, wherein a clamping member (40) inserted into the recess (21) is configured to fix the mixing blade portion (31) in the recess (21), wherein the recess (21) comprises a first recess portion (21a) and a second recess portion (21b), wherein the mixing blade portion (31) is arranged in the first recess portion (21a), and the clamping member (40) is at least partially arranged in the second recess portion (21b), characterized in that the first recess portion (21a) and the second recess portion (21b) are adjacently arranged in a plane extending perpendicular to the tool axis (100).

2. Mixing shaft (1) according to the preceding claim, characterized in that The mixing shaft (1) is configured to rotate about the tool axis (100) in a rotational direction, wherein the second recessed portion (21b) is arranged downstream of the first recessed portion (21a) in the rotational direction.

3. The mixing shaft (1) according to any one of the preceding claims, characterized in that The clamping member (40) comprises an anti-corrosion coating, wherein the coating is preferably a cadmium or phosphate coating.

4. The mixing shaft (1) according to any one of the preceding claims, characterized in that The clamping member (40) is fixed to the tool holder (20) in the recess (21) by means of a screw (41), wherein the screw (41) preferably extends through a through hole (42) of the clamping member into a threaded hole (22) in a rear wall (23) of the recess (21) in the tool holder (20).

5. Mixing shaft (1) according to the preceding claim, characterized in that A release device (50) is provided to release the clamping member (40) from the recess (21), preferably wherein: The release device (50) is connected to a portion of the screw (41) in a form-fitting or integral manner, wherein the release device (50) is arranged between the clamping member (40) and the rear wall (23) of the recess (21).

6. Mixing shaft (1) according to the preceding claim, characterized in that The release device (50) is shaped as a disk, wherein preferably, the outer peripheral surface of the disk is shaped as a circle and has no sharp edge.

7. The mixing shaft (1) according to any one of claims 5 or 6, characterized in that The release device (50) is arranged at a distance from the clamping member (40).

8. The mixing shaft (1) according to any one of claims 5 to 7, characterized in that A seal (60) is provided, which is preferably made of plastic material, particularly preferably made of polyurethane, and is arranged on a part of the screw (41) between the release device (50) and the rear wall (23) of the recess (21), so that the threaded opening (22) in the rear wall (23) of the recess (21) is sealed by the screw (41) and the seal (60) when the clamping member (40) is installed.

9. Mixing shaft (1) according to any one of the preceding claims, characterized in that The clamping member (40) is formed as a one-piece member.

10. Mixing shaft (1) according to any of the preceding claims, characterized in that The clamping member (40) and the mixing blade part (31) and / or the mixing blade part (31) and the tool holder (20) are configured such that the clamping member (40) and the mixing blade part (31) and / or the mixing blade part (31) and the tool holder (20) form a form-fitting connection in the recess (21).

11. Mixing shaft (1) according to any one of the preceding claims, characterized in that The clamping member (40) is arranged between the mixing blade portion (31) and a side wall (24) of the second recess (21b) opposite to the mixing blade portion (31), wherein the clamping member (40) is supported on both the mixing blade portion (31) and the side wall (24), wherein the clamping member (40) and the mixing blade portion (31) and / or the side wall (24) each include wedge-shaped surfaces corresponding to each other.

12. Mixing shaft (1) according to any one of the preceding claims, characterized in that The clamping member (40) comprises a lubrication device, wherein the lubrication device comprises a receptacle (43) for lubricant and lubrication channels (44a, 44b) by means of which lubricant can be introduced from the receptacle (43) into the recess (21).

13. Mixing shaft (1) according to the preceding claim, characterized in that The clamping member (40) has a first side (40a) and a second side (40b) arranged one after another in the direction of the tool axis (100), wherein the first part (44a) of the lubrication channel on the first side (40a) and / or the second side (40b) of the clamping member (40) is formed as a recess, and preferably as a groove, and the second part (44b) of the lubrication channel provides a connection between the receiving portion (43) and the first part (44a) of the lubrication channel.

14. Mixing shaft (1) according to the preceding claim, characterized in that The clamping member (40) comprises an outer part and an inner part, wherein the outer part of the clamping member (40) is farther from the tool axis (100) than the inner part, wherein the lubrication channel is arranged in the outer part of the clamping member (40) so that only the outer part of the clamping member (40) and the corresponding part of the recess (21) are supplied with lubricant, wherein preferably, the outer part comprises an expansion portion in a radial direction relative to the tool axis (100), the expansion portion of the outer part being at most as large as the expansion portion of the inner part in the radial direction, wherein it is particularly preferred that the first part of the lubrication channel (44a) extends from a first lateral surface of the clamping member (40) to a second lateral surface of the clamping member (40), the first lateral surface being in contact with the mixing blade portion (31) in the recess (21), and the second lateral surface being opposite to the first lateral surface.

15. Mixing shaft (1) according to any one of the preceding claims, characterized in that At least one protective element (70) is provided, which is arranged in the second recess portion (21b) and comprises a greater distance from the tool axis (100) than the clamping member (40), so that the clamping member (40) is covered at least in cross section, wherein the protective element (70) at least partially, preferably completely, closes the second recess portion (21b).

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