Mixing shaft

Abstract

The present invention relates to a mixing shaft having a tool holder, which is rotatable about a tool axis, and at least one mixing vane, wherein the tool holder has at least one cutout in which a mixing vane portion of the at least one mixing vane is received, wherein a clamping part, which is inserted into the cutout, is provided for fixing the mixing vane portion in the cutout, wherein the cutout has a first and a second cutout portion, wherein the mixing vane portion is arranged in the first cutout portion and the clamping part is arranged at least partially in the second cutout portion, characterized in that the first cutout portion and the second cutout portion are arranged next to each other in a plane which runs perpendicular to the tool axis.

Description

[0001] Mixing shaft

[0002] The present invention relates to a mixing shaft with a tool holder rotatable about a tool axis and at least one mixing blade. The tool holder has at least one recess in which a mixing blade section of the at least one mixing blade is received. A clamping part inserted into the recess is provided to fix the mixing blade section in the recess. For this purpose, the recess is divided into a first and a second recess section, with the mixing blade section being arranged in the first recess section and the clamping part being arranged at least partially in the second recess section.

[0003] Mixing shafts of the type mentioned above are used in various mixers known from the prior art. The mixing shaft is typically arranged approximately perpendicular to the bottom of the mixing container. To thoroughly mix the material in the mixer, a tool holder of a mixing shaft often has several mixing blades arranged one behind the other in several planes along the tool axis and extending radially outward from the tool axis of the mixing shaft.

[0004] When the mixing shaft rotates around the tool axis during operation, the mix flows past the mixing blades, causing them to wear and require regular replacement. It has been shown that mixing blades covered by a higher layer of mix, i.e., those positioned close to the bottom of the vessel, wear significantly faster than mixing blades positioned close to the surface of the mix, i.e., further away from the bottom of the vessel.

[0005] It is therefore already known from the prior art to be able to individually remove the mixing blades from the tool holder and replace them with new ones. The aim is to make the replacement of the mixing blades as quick and easy as possible. For this purpose, it is known from the prior art to clamp the mixing blades in the recess of the tool holder using a clamping device. A corresponding clamping device is known, for example, from EP 3 439 774 B1. A first recess section, in which a section of the mixing blade is arranged, is arranged above a second recess section, viewed in the direction of the tool axis, in which second recess section a clamping part for fixing the mixing blade is inserted. The clamping part consists of several components and is fixed in the recess by means of several screws.

[0006] However, this complex clamping system is difficult to install and remove. Furthermore, due to their location below or above the mixing blade, the clamping components are sometimes difficult to access and are subject to significant wear from the flowing mix. Finally, with this clamping system, the mixing blade, which is positioned closest to the tank bottom and ideally positioned as close to the tank bottom as possible, also requires adjustment.

[0007] The present invention is therefore based on the object of providing a mixing shaft with a tool holder which allows a particularly simple replacement of the mixing blades.

[0008] The object underlying 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 next to one another in a plane which runs perpendicular to the tool axis.

[0009] In other words, the clamping part is arranged in the same plane as the mixing blade section when viewed in the direction of the tool axis and not, as in clamping systems known from the prior art, one behind the other along the tool axis.

[0010] This offers the advantage that the clamping part is easily accessible and is not located beneath a mixing blade. Therefore, tools required for replacement can be used without colliding with the mixing blade.

[0011] In addition, only one recess in the circumferential direction is required in the tool holder, rather than two recesses arranged one above the other. This simplifies the removal of the mixing blades from the tool holder and their installation in the tool holder. These advantages lead to a more efficient replacement of the mixing blades compared to prior art mounting options.

[0012] In one embodiment, the mixing shaft is intended to be rotated in a direction of rotation about the tool axis, wherein the second recess section is arranged after the first recess section in the direction of rotation.

[0013] This offers the advantage that the clamping part is positioned in the flow shadow of the mixing blade, thus effectively protecting it against wear. Due to the flow over the mixing blade, there is no or only very little flow through the mixing material.

[0014] In a further embodiment, the clamping part has a corrosion-resistant coating, preferably a cadmium or phosphate coating. This measure also extends the service life of the clamping part. Furthermore, removal of the clamping part is simplified, as adhesion of the clamping part is reduced, even after extended periods of installation and operation of the mixer.

[0015] In a further embodiment, the clamping part is fixed to the tool holder in the recess using a screw, wherein the screw preferably extends through a through-hole in the clamping part into a threaded opening arranged in a rear wall of the recess in the tool holder. Preferably, the clamping part is connected to the tool holder radially relative to the tool axis. The clamping system according to the invention is thus secured using only a single screw, which allows for quick replacement of the mixing blades.

[0016] In a further embodiment, a release device is provided to release the clamping part from the recess.

[0017] Such a release device can, for example, be a pressure screw that is brought into engagement with a corresponding forcing thread that is implemented in the through-hole of the clamping part. It is understood that the forcing thread and the pressure screw have a larger diameter than the screw that is intended to fasten the clamping part in the recess, so that the fastening screw is passed through the forcing thread to fasten the clamping part in the recess. As soon as the fastening screw for removing the mixing blade has been removed, the pressure screw is screwed into the forcing thread and exerts a force on the rear wall of the recess, causing the clamping part to be released from it. Alternatively, a knock-out device can be fastened in the through-hole of the clamping part as the release device, with which the clamping part is knocked out of the recess.

[0018] However, these solutions have the disadvantage that impurities can become trapped in the forcing thread and the threads therefore have to be re-cut regularly, which requires an additional work step.

[0019] In one embodiment, the release device is therefore preferably connected to a portion of the screw in a form-fitting or integral manner, with the release device being arranged between the clamping part and the rear wall of the recess. The integral connection is preferably established by a welded or adhesive connection.

[0020] By providing a release mechanism on the screw for securing the clamping part, the additional step of removing the clamping part, such as using a pressure screw or a removal device, is eliminated. Unscrewing the screw, the release mechanism immediately releases the clamping part in the recess.

[0021] In a further embodiment, the release device is designed as a disc, with an outer peripheral surface of the disc preferably being round and edgeless. This ensures that the release device can move even if mixing material has penetrated between the release device and an inner part of the recess. This prevents the release device from jamming.

[0022] In particular, in a further embodiment, the release device is arranged at a distance from the clamping part in order to prevent jamming with the screw.

[0023] In a further embodiment, a seal, preferably made of plastic and particularly preferably made of polyurethane, is provided, which is arranged between the release device and the rear wall of the recess on a section of the screw in such a way that the threaded opening in the rear wall of the recess is sealed by the screw and the seal when the clamping part is installed. The seal thus protects the threaded opening in the recess of the tool holder from contamination caused by mixing material that has penetrated it, which in turn simplifies the removal of the clamping part and thus the mixing blade. In a preferred embodiment, the clamping part is designed in one piece. Therefore, to replace the mixing blade, several components of the clamping part do not have to be removed, which allows for a faster replacement. A one-piece connection is understood to be a connection that cannot be removed again without causing damage.The clamping part can, for example, be made in one casting or welded together from several components.

[0024] It is understood, however, that the clamping part according to the invention can also be designed in two or more parts.

[0025] In a further embodiment, the clamping part and the mixing blade section and / or the mixing blade section and the tool holder are designed such that the clamping part and the mixing blade section and / or the mixing blade section and the tool holder form a positive connection in the recess. This offers the advantage that the mixing blade section is not only fixed in the recess with the help of the clamping part in a force-fitting manner, but also a positive connection ensures that the mixing blade section cannot be removed from the recess without removing the clamping part. The clamping part is thus mechanically in the way of the mixing blade section. Alternatively or additionally, the mixing blade section is positively connected to the tool holder, so that this connection also contributes to the secure holding of the mixing blade.

[0026] The positive connection between the mixing blade section on the one hand and the clamping part or tool holder on the other hand is preferably achieved via a pin connection. It is understood that a triangular connection, an L-shaped connection, or other connection geometries are also possible for a positive connection.

[0027] In particular, in a further embodiment, the clamping part is arranged between the mixing blade section and a side wall of the second recess section opposite the mixing blade section, wherein the clamping part is supported both on the mixing blade section and on the side wall, wherein both the clamping part and the mixing blade section and / or the side wall have mutually corresponding wedge surfaces. In the context of the present invention, a wedge surface is understood to be a surface that has a wedge-shaped geometry in a plane perpendicular to the tool axis. The wedge surfaces offer the advantage that the mixing blade section is not only held in the recess by force-fitting means by clamping, but also that there is a positive connection between the mixing blade section and the clamping part.If the clamping part is designed in several parts, the corresponding wedge surfaces can also be additionally realized between the individual components of the clamping part.

[0028] In a further embodiment, the clamping part has a lubricating device, wherein the lubricating device has a receptacle for lubricant and a lubrication channel through which lubricant can be introduced from the receptacle into the recess. The lubricating device can be used to protect the recess with grease or another filling medium against the ingress of mixing material or water, which, for example, can act on the mixing shaft during operation of the mixer or during pressure cleaning of the mixer.

[0029] In particular, in one embodiment, the clamping part has a first side and a second side, which are arranged one behind the other in the direction of the tool axis. A first section of the lubrication channel is designed as a recess and preferably as a groove on the first side and / or the second side of the clamping part, and a second section of the lubrication channel provides a connection between the receptacle and the first section of the lubrication channel. In other words, this arrangement transports lubricant from the receptacle to the contact surfaces of the clamping part with the recess, i.e. the first and / or second side. It is understood that in one embodiment, the first section therefore consists of at least two parts, one part being arranged on the first side and the other part on the second side.

[0030] In a further embodiment, the clamping part has an outer section and an inner section, wherein the outer section is spaced further from the tool axis than the inner section of the clamping part, wherein the lubrication channel is arranged in the outer section of the clamping part, so that only the outer section of the clamping part and a corresponding section of the recess are supplied with lubricant. Preferably, the outer section has an extension in a radial direction to the tool axis that is at most as large as an extension of the inner section in the radial direction. In particular, in a further embodiment, the first section of the lubrication channel extends from a first side surface of the clamping part, which is in contact with the mixing blade section in the recess, to a second side surface of the clamping part, which is opposite the first side surface.This results in the lubricant being effectively distributed over the entire circumferential extent of the clamping part in the recess. The arrangement of the lubrication channel in the outer section of the clamping part has the advantage that, while the lubricant achieves an outward lubricating effect, the inner section of the clamping part is exposed to little or no lubricant, thus unaffected by the screw connection between the clamping part and the tool holder. At the same time, the inventive arrangement of the first lubrication channel section in the outer section of the clamping part also leads to lubricant savings.

[0031] In a further embodiment, at least one protective element is provided, which is arranged in the second recess section and is at a greater distance from the tool axis than the clamping part, such that the clamping part is covered, wherein the protective element at least partially, preferably completely, closes the second recess section. It is understood that a plurality of protective elements can also be provided, which, for example, cover individual bores such as the lubricant receptacle or the screw head in the through-opening of the clamping part. The protective element thus additionally protects the clamping part, in particular the screw heads and the lubricant receptacle, from the penetration of moisture or dirt through the mixing material or cleaning fluids, and thus extends the service life of the clamping part and its fastening means.

[0032] Further advantages, features, and possible applications will become clear from the following description of a preferred embodiment and the accompanying figures. Identical components are designated by the same reference numerals.

[0033] Figure 1 shows a perspective view of an embodiment of the mixing shaft according to the invention.

[0034] Figure 2 shows a partial cross-section through the mixing shaft shown in Figure 1 perpendicular to the tool axis.

[0035] Figure 3 shows a partial longitudinal section of a further embodiment of the mixing shaft according to the invention parallel to the tool axis.

[0036] Figure 4 shows a perspective view of a section of the mixing shaft shown in Figure 1.

[0037] The mixing shaft 1 shown in the figures comprises a tool holder 20 rotatable about a tool axis 100 and a plurality of mixing blades 30. Recesses 21 are provided in the tool holder 20, in which a mixing blade section 31 of the mixing blades 30 is arranged together with a clamping part 40. The clamping part 40 serves to fix the mixing blade section 31 in the recess 21.

[0038] The detailed design of the fixation of the mixing blade section by means of the clamping part 40 is shown in particular in Figures 2 and 3.

[0039] As can be seen from Figure 2, the recess 21 consists of a first recess section 21a and a second recess section 21b. The mixing blade section 31 of the mixing blade 30 is received in the first recess section 21a. The clamping part 40 is arranged in the second recess section 21b. As can be seen in particular from Figure 2, the clamping part 40 and the mixing blade section 31 are arranged on a plane perpendicular to the tool axis 100.

[0040] The clamping part 40 is fixed in the second recess section 21b by means of a screw 41. For this purpose, the screw 41 is passed through a through-hole 42 of the clamping part 40 and engaged with a threaded opening 22 arranged in a rear wall 23 of the recess 21.

[0041] When the clamping part 40 is arranged and fixed in the second recess portion 21b, the clamping part 40 is arranged between the mixing blade portion 31 and a side wall 24 of the recess 21 such that it clamps the mixing blade portion 31 in the first recess portion 21a, so that the mixing blade 30 is securely held in the tool holder 20.

[0042] For additional fixing of the mixing blade section 31 in the first recess section 21a, a pin 80 is also provided, which creates a positive connection between the tool holder 20 and the mixing blade section 31.

[0043] If the mixing shaft shown in Figure 1 is rotated counterclockwise, the second recess section 21b is arranged after the first recess section 21a in the direction of rotation. Thus, the second recess section 21b is located in the flow shadow of the mixing blade 30, so that the clamping part 40 is exposed to less wear from the mixing material flowing past. This, in turn, increases the service life of the clamping part 40. However, since the mixing blades 30 are also subject to wear from the mixing material flowing past, which also varies depending on the position of the mixing blades 30 along the tool axis 100, the mixing blades 30 must be replaced individually. To detach the mixing blade 30 from the tool holder 20, the clamping part 40 must be removed.

[0044] In order to release the clamping part 40 from the second recess section 21 b and thus to be able to replace the mixing blade 30, the screw 41 has a release device 50 shown in Figure 3, which is integrally connected to the screw 41 and is arranged between the clamping part 40 and the rear wall 23 of the recess 21.

[0045] In detail, the release device 50 is arranged as an annular disk on a threaded portion of the screw 41 such that a distance exists between the release device 50 and the clamping part 40 in order to prevent jamming of the screw 41 with the clamping part 40 on the one hand and with possibly penetrated mixing material on the other hand.

[0046] If the screw 41 is unscrewed from the threaded opening 22 of the rear wall 23 of the recess 21, this leads to a release of the clamping part 40. An additional work process for removing the clamping part 40 from the recess 21 is thus eliminated.

[0047] To protect the threaded opening 22 of the recess 21 from contamination by the mixing material, 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 designed as an annular disc and is made, for example, of polyurethane or another sealing material.

[0048] For additional sealing of the recess 21 from the mixing material, the clamping part 40 further comprises a lubricating device, which is particularly illustrated in Figure 4. The lubricating device consists of a receptacle 43 for lubricant and a lubricating channel, which consists of first sections 44a and a second section 44b.

[0049] The clamping part 40 is designed such that it has 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 sections 44a of the lubrication channel are formed as a groove on the first side 40a and the second side 40b of the clamping part (see also Figure 3). The second section 44b of the lubrication channel forms a connection between the lubricant receptacle 43 and the first sections 44a of the lubrication channel. If necessary, in particular for sealing purposes, the first sections 44a of the lubrication channel can also be extended to the side surfaces of the clamping part 40, which extend parallel to the tool axis.

[0050] As can be seen in particular from Figure 4, the lubrication channel is arranged in an outer section of the clamping part 40, which is further spaced from the tool axis 100 than an inner section of the clamping part 40. An extension of the outer section of the clamping part 40 in the radial direction to the tool axis 100 is equal to an extension of the inner section in the radial direction. This results in only the outer section of the clamping part 40 and a corresponding section of the recess 21 being supplied with lubricant, thus saving lubricant. At the same time, the lubrication of the clamping part 40 seals off the second recess section 21b against external influences. This includes, in particular, the flow of mixing material, but also influences that act on the mixing shaft, for example, during high-pressure cleaning of the mixing shaft.

[0051] In addition, the screw 41, which fixes the clamping part 40 in the second recess section 21b, is also effectively protected from external influences, so that the clamping part 40 can be loosened with simple means even after a longer downtime of the mixing shaft 1 and a replacement of the mixing blade 30 can be carried out particularly easily.

[0052] Finally, a protective element 70 is also provided, which is also arranged in the second recess section 21 b and has a greater distance from the tool axis 100 than the clamping part 40. The protective element 70 is designed such that it covers a radially outer side of the clamping part 40 and additionally protects it from external influences.

[0053] Alternatively, protective elements 70 can also be provided in a radially outer region of the clamping part 40, which only cover the lubricant receptacle 43 and the through opening 42, for example in the form of one or more plugs (see Figure 2).

[0054] Reference symbol

[0055] 1 mixing shaft

[0056] 20 tool holders

[0057] 21 recess

[0058] 21a first recess section

[0059] 21b second recess section

[0060] 22 threaded opening

[0061] 23 Rear wall

[0062] 24 side wall

[0063] 30 mixing blades

[0064] 31 mixing wing section

[0065] 40 clamping part

[0066] 40a first side of the clamping part

[0067] 40b second side of the clamping part

[0068] 41 Screw

[0069] 42 passage opening

[0070] 43 Lubricant intake

[0071] 44a first section of the lubricant channel

[0072] 44b second section of the lubricant channel

[0073] 50 release device

[0074] 60 Seal

[0075] 70 protective element

[0076] 80 pen

[0077] 100 tool axis

Claims

Patent claims 1. Mixing shaft (1) with a tool holder rotatable about a tool axis (100) (20) and at least one mixing blade (30), wherein the tool holder (20) has at least one recess (21) in which a mixing blade section (31) of the at least one mixing blade (30) is received, wherein a clamping part (40) inserted into the recess (21) for fixing the mixing blade section (31) in the recess (21) is provided, wherein the recess (21) has a first and a second recess section (21a, 21b), wherein the mixing blade section (31) is arranged in the first recess section (21a) and the clamping part (40) is arranged at least partially in the second recess section (21b), characterized in that the first recess section (21a) and the second recess section (21b) are arranged next to one another in a plane which runs perpendicular to the tool axis (100).

2. Mixing shaft (1) according to the preceding claim, wherein the mixing shaft (1) is intended to be rotated in a direction of rotation about the tool axis (100), wherein the second recess portion (21b) is arranged after the first recess portion (21a) in the direction of rotation.

3. Mixing shaft (1) according to one of the preceding claims, wherein the clamping part (40) has a coating against corrosion, wherein the coating is preferably a cadmium or phosphate coating.

4. Mixing shaft (1) according to one of the preceding claims, wherein the clamping part (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-opening (42) of the clamping part into a threaded opening (22) which is arranged in a rear wall (23) of the recess (21) in the tool holder (20).

5. Mixing shaft (1) according to the preceding claim, wherein a release device (50) is provided to release the clamping part (40) from the recess (21), wherein preferably the release device (50) is positively or integrally connected to a portion of the screw (41), wherein the release device (50) is arranged between the clamping part (40) and the rear wall (23) of the recess (21).

6. Mixing shaft (1) according to the preceding claim, wherein the release device (50) is designed as a disc, wherein preferably an outer peripheral surface of the disc is round and without edges.

7. Mixing shaft (1) according to one of claims 5 or 6, wherein the release device (50) is arranged at a distance from the clamping part (40).

8. Mixing shaft (1) according to one of claims 5 to 7, wherein a seal (60), preferably made of plastic and particularly preferably made of polyurethane, is provided, which is arranged between the release device (50) and the rear wall (23) of the recess (21) on a section of the screw (41) in such a way that the threaded opening (22) in the rear wall (23) of the recess (21) is sealed by the screw (41) and the seal (60) in the installed state of the clamping part (40).

9. Mixing shaft (1) according to one of the preceding claims, wherein the clamping part (40) is designed in one piece.

10. Mixing shaft (1) according to one of the preceding claims, wherein the clamping part (40) and the mixing blade section (31) and / or the mixing blade section (31) and the tool holder (20) are designed such that the clamping part (40) and the mixing blade section (31) and / or the mixing blade section (31) and the tool holder (20) form a positive connection in the recess (21).

11. Mixing shaft (1) according to one of the preceding claims, wherein the clamping part (40) is arranged between the mixing blade section (31) and a side wall (24) of the second recess section (21 b) opposite the mixing blade section (31), wherein the clamping part (40) is supported both on the mixing blade section (31) and on the side wall (24), wherein both the clamping part (40) and the mixing blade section (31) and / or the side wall (24) have wedge surfaces corresponding to one another.

12. Mixing shaft (1) according to one of the preceding claims, wherein the clamping part (40) has a lubricating device, wherein the lubricating device has a receptacle (43) for lubricant and a lubricating channel (44a, 44b) with which lubricant can be introduced from the receptacle (43) into the recess (21).

13. Mixing shaft (1) according to the preceding claim, wherein the clamping part (40) has a first side (40a) and a second side (40b) which are directed in the direction of the tool axis (100) are arranged one behind the other, wherein a first section (44a) of the lubrication channel is formed as a recess and preferably as a groove on the first side (40a) and / or the second side (40b) of the clamping part (40), and a second section (44b) of the lubrication channel provides a connection between the receptacle (43) and the first section (44a) of the lubrication channel. Mixing shaft (1) according to the preceding claim, wherein the clamping part (40) has an outer section and an inner section, wherein the outer section is spaced further from the tool axis (100) than the inner section of the clamping part (40), wherein the lubrication channel is arranged in the outer section of the clamping part (40) so that only the outer section of the clamping part (40) and a corresponding section of the recess (21) are supplied with lubricant, wherein the outer section preferably has an extension in a radial direction to the tool axis (100).which is at most as large as an extension of the inner section in the radial direction, wherein the first section of the lubrication channel (44a) particularly preferably extends from a first side surface of the clamping part (40), which is in contact with the mixing blade section (31) in the recess (21), to a second side surface of the clamping part (40) that is opposite the first side surface. Mixing shaft (1) according to one of the preceding claims, wherein at least one protective element (70) is provided, which is arranged in the second recess section (21b) and is at a greater distance from the tool axis (100) than the clamping part (40), so that the clamping part (40) is covered at least in sections, wherein the protective element (70) closes the second recess section (21b) at least partially, preferably completely.

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