Mixing shaft

Abstract

The present 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 has at least one recess into which a mixing blade portion of the at least one mixing blade is received, and a clamping member inserted into the recess is configured to secure the mixing blade portion within the recess, the recess having a first recessed portion and a second recessed portion, the mixing blade portion being disposed within the first recessed portion and the clamping member being at least partially disposed within the second recessed portion, and wherein the first recessed portion and the second recessed portion are disposed adjacent to each other in a plane extending perpendicular to the tool axis.

Description

[Technical Field]

[0001] The present invention relates to a mixing shaft having a tool holder rotatable about a tool axis and at least one mixing blade, the tool holder having at least one recess into which a mixing blade section of the at least one mixing blade is received, and a fastening member configured to be inserted into the recess to secure the mixing blade section in the recess, the recess being divided into a first recess portion and a second recess portion, the mixing blade section being disposed in the first recess portion and the fastening member being at least partially disposed in the second recess portion. [Background technology]

[0002] Mixing shafts of the above type are used in various mixers known from the prior art, where they are usually arranged approximately perpendicular to the bottom of the mixing vessel. To mix the materials to be mixed in the mixer, the tool holder of the mixing shaft often has a number of mixing vanes arranged alternately in a number of planes along the tool axis and extending radially outward from the tool axis of the mixing shaft.

[0003] When the mixing shaft is rotated about the tool axis during operation of the mixer, the material to be mixed flows past the mixing blades, causing them to wear and requiring periodic replacement. It has been found that mixing blades covered by a higher bed height of material to be mixed, i.e., those arranged near the bottom of the vessel, wear much faster than mixing blades that are closer to the surface of the material to be mixed, i.e., located further from the bottom of the mixing vessel.

[0004] For this reason, it is already known from the prior art that the mixing blades can be removed individually from the tool holder and replaced with new mixing blades, the aim being to change the mixing blades as quickly and easily as possible.

[0005] For this purpose, it is known from the prior art to clamp the mixing blade in a recess of a tool holder using a clamping device. A corresponding clamping device is known, for example, from EP 0 999 543 A1. In this case, when viewed in the direction of the tool axis, a first recess portion in which part of the mixing blade is located is arranged above a second recess portion into which a clamping element is inserted to fix the mixing blade. The clamping element is made up of several parts and is fixed in the recess by several screws.

[0006] However, this complex clamping system cannot be installed and removed without much effort. In addition, the clamping elements are sometimes difficult to access because they are located below or above the mixing blades, and the clamping elements are correspondingly exposed to greater wear from the materials to be mixed flowing through them. Finally, this clamping system also requires that mixing blades be employed that are located closest to the bottom of the vessel and, at best, guided as close as possible to the bottom of the vessel. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] European Patent No. 3439774 Summary of the Invention [Problem to be solved by the invention]

[0008] SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide a mixing shaft with a tool holder which makes it possible to simplify the replacement of the mixing blades in particular. [Means for solving the problem]

[0009] The object underlying the present invention is solved by a mixing shaft of the type mentioned at the outset, in which the first recessed portion and the second recessed portion are arranged adjacent to each other in a plane extending perpendicular to the tool axis.

[0010] In other words, the clamping members are arranged in one plane with the mixing vane 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.

[0011] This provides the advantage that the clamping member is easily accessible and is not located below the mixing blade, so that the tools required for replacement can be inserted without hitting the mixing blade.

[0012] In addition, only one recess needs to be fitted into the tool holder in the circumferential direction, and two recesses need not be arranged one above the other. This simplifies not only the removal of the mixing blade from the tool holder, but also the installation of the mixing blade into the tool holder. Overall, these advantages result in a more efficient replacement of the mixing blade compared to the mounting options known from the prior art.

[0013] In one embodiment, the mixing shaft is configured to be rotationally rotated about the tool axis, and the second recessed portion is rotationally disposed downstream of the first recessed portion.

[0014] This has the advantage that the clamping element is located in the flow shadow of the mixing blade and is therefore effectively protected from wear. As a result of the flow above the mixing blade, there is no or very little incident flow through the materials to be mixed.

[0015] In a further embodiment, the clamping member is provided with a corrosion-resistant coating, preferably a cadmium or phosphate coating. This measure also extends the service life of the clamping member. In addition, removal of the clamping member is simplified, since the adhesion of the clamping member is reduced even after a long period of installation and operation of the mixer.

[0016] In another embodiment, the clamping member is fastened to the tool holder in the recess by means of a screw, which preferably extends through a through-hole in the clamping member into a threaded hole arranged in the rear wall of the recess in the tool holder. Preferably, the clamping member is connected to the tool holder radially relative to the tool axis. The clamping system according to the invention is therefore fixed by only a single screw, which allows for quick replacement of the mixing vane.

[0017] In a further embodiment, the release device is configured to release the fastening member from the recess.

[0018] Such a release device may be, for example, a pressure screw engaged with a corresponding force-release screw mounted in the through-hole of the clamping member. Obviously, the force-release screw and the pressure screw have a larger diameter than the screw adapted to fix the clamping member in the recess, so that the fixing screw is guided through the force-release screw to fix the clamping member in the recess. When the fastening screw for removing the mixing blade is removed, the pressure screw is screwed into the force-release thread and exerts a force on the rear wall of the recess, thereby releasing the clamping member from the recess.

[0019] Alternatively, an ejector device may be fastened into the through-hole of the clamping member as a release device, with which the clamping member is ejected from the recess.

[0020] However, these solutions have the drawback that impurities can accumulate in the force-release screw, so that the threads have to be periodically re-cut, which requires an additional work step.

[0021] Therefore, preferably in one embodiment the release device is positively or integrally connected to a portion of the screw, the release device being arranged between the clamping member and the rear wall of the recess, whereby the integral connection is preferably provided by a welded or adhesive connection.

[0022] By providing a release device on the screw for fastening the clamping member, an additional work step for removing the clamping member, for example by means of a pressure screw or an ejector device, is eliminated. When the screw is loosened, the release device brings about the immediate release of the clamping member in the recess.

[0023] In a further embodiment, the release device is formed as a disk, preferably with a rounded outer periphery without corners, which ensures that the release device can also move if the material to be mixed penetrates between the release device and the inner part of the recess, which counteracts clogging of the release device.

[0024] In particular, in a further embodiment, the release device is arranged remotely from the clamping member to prevent jamming with the screw.

[0025] In a further embodiment, a seal, preferably made of a plastic material, particularly preferably polyurethane, is provided, which is arranged over part of the screw between the release device and the rear wall of the recess, such that the threaded opening in the rear wall of the recess is sealed by the screw and the seal when the clamping member is installed. The seal thus protects the threaded opening in the tool holder recess from contamination by the material to be mixed that has entered, thus simplifying removal of the clamping member and thus the mixing blade.

[0026] In a preferred embodiment, the clamping member is formed as an integral member. As a result, in order to replace the mixing vane, it is not necessary to release several parts of the clamping member, thus allowing the replacement to proceed more quickly. An integral connection is understood to mean a connection that cannot be non-destructively disconnected. The clamping member may, for example, be manufactured from a single casting or may be welded together from several parts.

[0027] However, it is self-evident that the clamping member according to the invention can also be designed in two or more parts.

[0028] In a further embodiment, the clamping member and the mixing blade section, and / or the mixing blade section and the tool holder, are configured such that they form a secure connection within the recess. This has the advantage that not only is the mixing blade section forcibly locked within the recess by the clamping member, but the secure connection also ensures that the mixing blade section cannot be removed from the recess without removing the clamping member. The clamping member thus mechanically blocks the mixing blade section. Alternatively or additionally, the mixing blade section is securely connected to the tool holder, which also contributes to a stable fixation of the mixing blade.

[0029] The secure connection between the mixing blade portion on the one hand and the clamping member or tool holder on the other hand is preferably provided by a pin connection, although obviously, a triangular connection, an L-shaped connection or another connection shape can also be used as an alternative for the secure connection.

[0030] In particular, in a further embodiment, the clamping member is disposed between the mixing flight section and the sidewall of the second recessed section opposite the mixing flight section, the clamping member being supported by both the mixing flight section and the sidewall, and both the clamping member and the mixing flight section and / or the sidewall having corresponding wedge surfaces. In the present invention, a wedge surface is understood to mean a surface having a wedge-shaped shape in a plane perpendicular to the tool axis. The advantage of the wedge surface is that not only is the mixing flight section held in the recess by friction due to clamping, but there is also a secure fit between the mixing flight section and the clamping member.

[0031] If the clamping member has a multi-part design, mutually corresponding wedge surfaces can additionally be realized between the individual parts of the clamping member as well.

[0032] In a further embodiment, the clamping member comprises a lubrication device that not only comprises a receptacle for the lubricant but also 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 against the ingress of the material to be mixed or water with grease or another filling medium that acts on the mixing shaft, for example, during operation of the mixer or pressure washing of the mixer.

[0033] In particular, in one embodiment, the clamping member has a first side and a second side alternately arranged in the tool axis direction. Here, the first portion of the lubrication channel is formed as a recess, preferably as a groove on the first side and / or the second side of the clamping member, and the second portion of the lubrication channel provides a connection between the socket and the first portion of the lubrication channel. In other words, this arrangement transports lubricant from the socket to the contact surface of the clamping member with the recess, i.e., the first and / or second side. Obviously, therefore, in one embodiment, the first portion includes at least two sub-portions, one sub-portion arranged on the first side and another sub-portion arranged on the second side.

[0034] In another embodiment, the clamping member includes an outer portion and an inner portion, the outer portion being farther from the tool axis than the inner portion of the clamping member, and the lubrication channel is disposed in the outer portion of the clamping member, thereby supplying lubricant only to the outer portion of the clamping member and the corresponding portion of the recess. Preferably, the outer portion has a radial dimension relative to the tool axis that is at most as large as the radial dimension of the inner portion. In particular, in a further embodiment, a first portion of the lubrication channel extends from a first side of the clamping member that contacts the mixing vane portion in the recess to a second side of the clamping member opposite the first side. This results in the lubricant being effectively distributed throughout the entire circumferential extent of the clamping member within the recess.

[0035] Placing the lubrication channel on the outer part of the clamping member has the advantage that although the lubricant achieves a lubricating effect on the outside, the inner part of the clamping member is only affected by a small amount of lubricant or not affected at all, so that the screw connection of the clamping member to the tool holder is not affected. At the same time, placing the first lubrication channel portion within the outer part of the clamping member according to the present invention also results in a saving of lubricant.

[0036] In a further embodiment, at least one protective element is provided which is arranged within the second recess and is further away from the tool axis than the clamping member, so that the clamping member is covered and the protective element at least partially, preferably completely, closes the second recess. It is obvious that, for example, a plurality of protective elements may also be provided which cover individual holes such as the lubricant receptacle or the screw head within the through-hole of the clamping member. The protective element thus additionally protects the clamping member, in particular the screw head and the lubricant receptacle, against the ingress of moisture or dirt by the mixing material or the cleaning liquid, and thereby extends the service life not only of the clamping member but also of its fastening means.

[0037] Further advantages, features and possible uses will become apparent from the following description of the preferred embodiments and the accompanying drawings. The same parts are given the same reference numerals.

Brief Description of the Drawings

[0038] [Figure 1] It is a perspective view of an embodiment of a mixing shaft according to the present invention. [Figure 2] It is a partial cross-sectional view of the mixing shaft shown in FIG. 1 taken perpendicular to the tool axis. [Figure 3] It is a partial longitudinal cross-sectional view of a further embodiment of a mixing shaft according to the present invention taken parallel to the tool axis. [Figure 4] It is a perspective view of the cross-section of the mixing shaft shown in FIG. 1.

Embodiments for Carrying out the Invention

[0039] 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. Within the tool holder 20 are recesses 21 in which mixing blade sections 31 of the mixing blades 30 are located together with clamping members 40. The clamping members 40 serve to secure the mixing blade sections 31 within the recesses 21.

[0040] The detailed structure of the fixing of the mixing vane section by the fastening member 40 is particularly shown in FIGS.

[0041] As can be seen in Figure 2, recess 21 is comprised of first recess portion 21a and second recess portion 21b. Mixing blade portion 31 of mixing blade 30 is received within first recess portion 21a. Clamping member 40 is disposed within second recess portion 21b. As can be seen particularly in Figure 2, clamping member 40 and mixing blade portion 31 are disposed in a plane extending perpendicular to tool axis 100.

[0042] The clamping member 40 is press-fit into the second recessed portion 21b by means of a screw 41. For this purpose, the screw 41 is threaded through a through-hole 42 in the clamping member 40 and into a threaded hole 22 arranged in the rear wall 23 of the recess 21.

[0043] When the clamping member 40 is disposed and secured within the second recessed portion 21b, the clamping member 40 is disposed between the mixing blade portion 31 and the side wall 24 of the recess 21, thereby clamping the mixing blade portion 31 within the first recessed portion 21a, thereby stably holding the mixing blade 30 within the tool holder 20.

[0044] To further secure the mixing flight section 31 within the first recessed section 21 a, a pin 80 is further provided to form a secure connection between the tool holder 20 and the mixing flight section 31 .

[0045] 1 is rotated counterclockwise, 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 shadow of the mixing blade 30, and the clamping member 40 is subjected to less wear caused by the material to be mixed flowing through it. This results in an increased service life of the clamping member 40.

[0046] However, the mixing flights 30 are also subject to wear from the material to be mixed flowing past them, and this wear additionally varies depending on the position of the mixing flight 30 along the tool axis 100, so the mixing flights 30 must be replaced individually. To remove the mixing flight 30 from the tool holder 20, the clamping members 40 must be removed.

[0047] To release the clamping member 40 from the second recessed portion 21b and replace the mixing blade 30, the screw 41 is provided with a release device 50, shown in FIG. 3, 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.

[0048] In particular, the release device 50 is arranged as an annular washer on the threaded portion of the screw 41 so that there is a distance between the release device 50 and the clamping member 40, thereby preventing clogging of the screw 41 with the clamping member 40 on the one hand and with the material to be mixed that may have been mixed in on the other hand.

[0049] When the screw 41 is unscrewed from the threaded opening 22 in the rear wall 23 of the recess 21, the clamping member 40 is released, thus eliminating the need for an additional operating step to remove the clamping member 40 from the recess 21.

[0050] To protect the threaded opening 22 of the recess 21 from contamination by the materials 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 disc and is made, for example, of polyurethane or another sealing material.

[0051] To further seal the recess 21 against the materials to be mixed, the clamping member 40 further comprises a lubrication device, which is shown in particular in Figure 4. The lubrication device consists of a receptacle 43 for a lubricant and a lubrication channel consisting of a first part 44a and a second part 44b.

[0052] The clamping member 40 is thus configured with first and second sides 40a, 40b that are alternately arranged in the direction of the tool axis 100. The first portions 44a of the lubrication channels are formed as grooves on the first and second sides 40a, 40b of the clamping member (see also FIG. 3). The second portions 44b of the lubrication channels form a connection between the lubricant receiving openings 43 and the first portions 44a of the lubrication channels. The first portions 44a of the lubrication channels may also be continuous with the side surfaces of the clamping member 40 that extend parallel to the tool axis, if necessary, particularly for sealing purposes.

[0053] As can be seen in particular from FIG. 4 , the lubrication channels are arranged in an outer portion of the clamping member 40, which is further from the tool shaft 100 than the inner portion of the clamping member 40. The radial dimension of the outer portion of the clamping member 40 relative to the tool shaft 100 is equal to the radial dimension of the inner portion. This means that only the outer portion of the clamping member 40 and the corresponding portion of the recess 21 are supplied with lubricant, thereby saving lubricant. At the same time, the lubrication of the clamping member 40 serves to seal the second recessed portion 21b against external influences. These influences include, in particular, the inflow of the materials to be mixed, but also influences acting on it during, for example, high-pressure cleaning of the mixing shaft.

[0054] In addition, the screws 41 fixing the clamping members 40 in the second recessed portions 21b are also effectively protected against external influences, so that the clamping members 40 can be loosened in a simple manner even after a longer service life of the mixing shaft 1, and the mixing blades 30 can be replaced particularly easily.

[0055] Finally, a protective element 70 is also provided, which is likewise arranged in the second recessed portion 21b and at a greater distance from the tool axis 100 than the clamping member 40. The protective element 70 is configured such that it covers the radially outer flank of the clamping member 40 and further protects the clamping member from external influences.

[0056] Alternatively, a protective element 70 may also be provided in the radially outer region of the clamping member 40, for example in the form of one or more plugs (see FIG. 2), which cover only the lubricant receiving opening 43 and the through-hole 42. [Explanation of symbols]

[0057] 1 Mixing Shaft 20 Tool holder 21 Depression 21a First recessed portion 21b Second recessed portion 22 threaded opening 23 Back wall 24 Side wall 30 Mixing Blade 31 Mixing blade section 40 Fastening member 40a First side of fastening member 40b second side of the clamping member 41 Screw 42 Through hole 43 Lubricant receiving port 44a: First portion of lubricant channel 44b Second portion of lubricant channel 50 Release device 60 stickers 70 Protection Elements 80 pins 100 tool axes

Claims

1. A mixing shaft (1) comprising a tool holder (20) rotatable around a tool axis (100) and at least one mixing vane (30) protruding from the outer circumferential surface of the tool holder (20), wherein the tool holder (20) has a recess (21) on its outer circumferential surface into which a mixing vane insertion portion (31) of the mixing vane (30) can be inserted, and a clamping member (40) inserted into the recess (21) is configured to fix the mixing vane insertion portion (31) within the recess (21), and the recess (21) A mixing shaft (1) comprising a first recessed portion and a second recessed portion (21a, 21b), wherein the mixing blade insertion portion (31) is located within the first recessed portion (21a), and the tightening member (40) is located at least partially within the second recessed portion (21b), characterized in that the first recessed portion (21a) and the second recessed portion (21b) are located adjacent to each other in a single plane extending perpendicular to the axial direction of the tool shaft (100).

2. The mixing shaft according to claim 1, wherein the mixing shaft (1) is configured to be rotated in a rotational direction around the tool axis (100), and the second recessed portion (21b) is located downstream of the first recessed portion (21a) in the rotational direction.

3. The mixed shaft according to claim 1 or 2, wherein the fastening member (40) is provided with a corrosion-preventive coating, and the corrosion-preventive coating is a cadmium coating or a phosphate coating.

4. The mixing shaft according to claim 1, wherein the fastening member (40) is fixed to the tool holder (20) in the recess (21) by a screw (41), and the screw (41) extends through a through hole (42) of the fastening member into a threaded hole (22) located in the back wall (23) of the recess (21) in the tool holder (20).

5. The mixing shaft according to claim 4, wherein a release device (50) is provided for releasing the tightening member (40) from the recess (21), the release device (50) is securely or integrally connected to a portion of the screw (41), and the release device (50) is positioned between the tightening member (40) and the back wall (23) of the recess (21).

6. The mixing shaft according to claim 5, wherein the release device (50) is formed as a disk, and the outer surface of the disk is formed to be round and without corners.

7. The mixing shaft according to claim 5 or 6, wherein the release device (50) is located away from the tightening member (40).

8. The mixing shaft according to claim 5 or 6, wherein a seal (60) made of a plastic material is provided, and the seal (60) is positioned on a portion of the screw (41) between the release device (50) and the back wall (23) of the recess (21) such that the threaded hole (22) in the back wall (23) of the recess (21) is sealed by the screw (41) and the seal (60) when the fastening member (40) is attached.

9. The mixing shaft according to claim 1, wherein the fastening member (40) is formed as an integral member.

10. The mixing shaft according to claim 1, wherein the combination of the clamping member (40) and the mixing blade insertion portion (31), and / or the combination of the mixing blade insertion portion (31) and the tool holder (20), is configured such that each of the combinations forms a secure connection within the recess (21).

11. The mixing shaft according to claim 1, wherein the clamping member (40) is positioned between the mixing blade insertion portion (31) and the side wall (24) of the second recessed portion (21b) opposite to the mixing blade insertion portion (31), the clamping member (40) is supported both on the mixing blade insertion portion (31) and on the side wall (24), and both the clamping member (40) and the mixing blade insertion portion (31), and / or both the clamping member (40) and the side wall (24) have corresponding wedge surfaces.

12. The mixing shaft according to claim 1, wherein the fastening member (40) is equipped with a lubrication device, the lubrication device comprising a receptacle (43) for a lubricant and lubrication channels (44a, 44b) through which the lubricant can be introduced from the receptacle (43) into the recess (21).

13. The mixing shaft according to claim 12, wherein the clamping member (40) has a first side (40a) and a second side (40b) arranged alternately in the direction of the tool axis (100), the first portion (44a) of the lubrication channel is formed as a recess or groove on the first side (40a) and / or the second side (40b) of the clamping member (40), and the second portion (44b) of the lubrication channel provides a connection between the socket (43) and the first portion (44a) of the lubrication channel.

14. The mixing shaft according to claim 13, wherein the clamping member (40) comprises an outer portion and an inner portion, the outer portion being further away from the tool shaft (100) than the inner portion of the clamping member (40), the lubrication channel being located within the outer portion of the clamping member (40) so that lubricant is supplied only to the outer portion of the clamping member (40) and the corresponding portion of the recess (21), the outer portion including a radial extension relative to the tool shaft (100) which is at most the same size as the radial extension of the inner portion, and the first portion (44a) of the lubrication channel extending from a first side of the clamping member (40) in contact with the mixing vane insertion portion (31) in the recess (21) to a second side of the clamping member (40) opposite to the first side.

15. The mixing shaft according to claim 1, wherein at least one protective element (70) is provided in the second recessed portion (21b) and is located at a greater distance from the tool shaft (100) than the clamping member (40), so that the clamping member (40) is at least partially covered and the protective element (70) at least partially closes the second recessed portion (21b).

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