MIXING SHAFT

Abstract

A mixing shaft has a tool holder rotatable about a tool axis and at least one mixing blade. The tool holder includes 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 fix the mixing blade portion in the recess. The recess includes a first and a second recess portion. The mixing blade portion is arranged in the first recess portion and the clamping member is arranged at least partly in the second recess portion, wherein the first recess portion and the second recess portion are arranged adjacently in one plane extending perpendicularly to the tool axis.

Claims

1. A mixing shaft comprising 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 the at least one mixing blade is received, wherein a clamping member inserted into the recess is configured to fix the mixing blade portion in the recess, wherein the recess comprises a first and a second recess portion, wherein the mixing blade portion is arranged in the first recess portion and the clamping member is arranged at least partially in the second recess portion, and wherein the first recess portion and the second recess portion are arranged adjacently in one plane extending perpendicularly to the tool axis.

2. The mixing shaft according to claim 1, wherein the mixing shaft is configured to be rotated in a rotational direction about the tool axis, wherein the second recess portion is arranged downstream of the first recess portion in the rotational direction.

3. The mixing shaft according claim 1, wherein the clamping member comprises a coating against corrosion.

4. The mixing shaft according to claim 1, wherein the clamping member is fixed to the tool holder in the recess by a screw wherein the screw extends through a through hole of the clamping member into a threaded hole arranged in a back wall of the recess in the tool holder.

5. The mixing shaft according to claim 4, wherein a release device is provided to release the clamping member from the recess wherein the release device is arranged between the clamping member and the rear wall of the recess.

6. The mixing shaft according to claim 5, wherein the release device is shaped as a disk.

7. The mixing shaft according to claim 5, wherein the release device is arranged at a distance from the clamping member.

8. The mixing shaft according claim 5, wherein a seal is provided, which is arranged between the release device and the rear wall of the recess on a portion 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 in the mounted state of the clamping member.

9. The mixing shaft according to claim 1, wherein the clamping member is formed as one-piece member.

10. The mixing shaft according to claim 1, wherein the clamping member and the mixing blade portion and/or the mixing blade portion and the tool holder are configured in such a way that the clamping member and the mixing blade portion and/or the mixing blade portion and the tool holder form a positive connection in the recess.

11. The mixing shaft according to claim 1, wherein the clamping member is arranged between the mixing blade portion and a side wall of the second recess portion opposite the mixing blade portion, wherein the clamping member is supported both on the mixing blade portion and on the side wall, wherein both the clamping member and the mixing blade portion and/or the side wall comprise wedge surfaces corresponding to each other.

12. The mixing shaft according to claim 1, wherein the clamping member comprises a lubrication device, wherein the lubrication device comprises a receptacle for lubricant and a lubrication channel by which lubricant can be introduced from the receptacle into the recess.

13. The mixing shaft according to claim 12, wherein the clamping member has a first side and a second side arranged one after the other in the direction of the tool axis, wherein a first portion of the lubrication channel is shaped as a recess and as a groove on the first side and/or the second side of the clamping member, and a second portion of the lubrication channel provides a connection between the receptacle and the first portion of the lubrication channel.

14. The mixing shaft according to claim 13, wherein the clamping member comprises an outer portion and an inner portion, wherein the outer portion is more distant from the tool axis than the inner portion of the clamping member, wherein the lubrication channel is arranged in the outer portion of the clamping member so that only the outer portion of the clamping member and a corresponding portion of the recess are supplied with lubricant, wherein the outer portion comprises an expansion in a radial direction to the tool axis which is maximally as large as an expansion of the inner portion in the radial direction, wherein the first portion of the lubrication channel extends from a first lateral surface of the clamping member which is in contact with the mixing blade portion in the recess to a second lateral surface of the clamping member which is opposite to the first lateral surface.

15. The mixing shaft according to claim 1, wherein 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 at least section-wise, wherein the protective element closes the second recess portion at least partially.

16. The mixing shaft according to claim 3, wherein the coating is a cadmium or phosphate coating.

17. The mixing shaft according to claim 5, wherein the release device is positively or integrally connected to a portion of the screw.

18. The mixing shaft according to claim 6, wherein an outer peripheral surface of the disk is shaped round and without edges.

19. The mixing shaft according to claim 14, wherein the outer portion comprises an expansion in a radial direction to the tool axis which is maximally as large as an expansion of the inner portion in the radial direction.

20. The mixing shaft according to claim 14, wherein the first portion of the lubrication channel extends from a first lateral surface of the clamping member which is in contact with the mixing blade portion in the recess to a second lateral surface of the clamping member which is opposite to the first lateral surface.

Description

[0036] Further advantages, features and possible applications will be apparent from the following description of a preferred embodiment and the accompanying figures. Identical components are marked with the same reference numbers.

[0037] FIG. 1 shows a perspective view of an embodiment of the mixing shaft according to the invention.

[0038] FIG. 2 shows a partial cross-section through the mixing shaft shown in FIG. 1 perpendicular to the tool axis.

[0039] FIG. 3 shows a partial longitudinal section of a further embodiment of the mixing shaft according to the invention parallel to the tool axis.

[0040] FIG. 4 shows a perspective view of a section of the mixing shaft shown in FIG. 1.

[0041] 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. In the tool holder 20, recesses 21 are provided in which a mixing blade portion 31 of the mixing blades 30 is arranged together with a clamping member 40. The clamping member 40 serves to fix the mixing blade portion 31 in the recess 21.

[0042] The detailed structure of the fixing of the mixing blade portion by means of the clamping member 40 is shown in particular in FIGS. 2 and 3.

[0043] As can be derived from FIG. 2, the recess 21 consists 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, the clamping member 40 is arranged. As can be seen in particular from FIG. 2, the clamping member 40 and the mixing blade portion 31 are arranged on one plane extending perpendicularly to the tool axis 100.

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

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

[0046] For additional fixation of the mixing blade portion 31 in the first recess portion 21a, a pin 80 is additionally provided to form a positive connection between the tool holder 20 and the mixing blade portion 31.

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

[0048] However, since the mixing blades 30 are likewise subject to wear due to the material to be mixed that flows past, which wear additionally 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 dismount the mixing blade 30 from the tool holder 20, the clamping member 40 must be removed.

[0049] To release the clamping member 40 from the second recess portion 21b and thereby replace the mixing blade 30, the screw 41 comprises a release device 50 shown in FIG. 3, that is integrally connected to the screw 41 and arranged between the clamping member 40 and the rear wall 23 of the recess 21.

[0050] In detail, the release device 50 is arranged as an annular washer on a threaded section of the screw 41 in such a way that there is a distance between the release device 50 and the clamping member 40 to prevent jamming 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, thus eliminating the need for an additional operational step for removing the clamping member 40 from the recess 21.

[0052] 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 shaped as an annular disc and is made, for example, of polyurethane or another sealing material.

[0053] For additional sealing of the recess 21 towards the material to be mixed, the clamping member 40 further comprises a lubricating device, which is shown in particular in FIG. 4. The lubrication device consists of a receptacle 43 for lubricant and a lubrication channel, which consists of first sections 44a and a second section 44b.

[0054] Thereby, the clamping member 40 is configured to have a first side 40a and a second side 40b, which are arranged one after the other in the direction of the tool axis 100. The first sections 44a of the lubrication channel are shaped as a groove on the first side 40a and the second side 40b of the clamping member (see also FIG. 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. The first sections 44a of the lubrication channel can also be continued, if necessary, in particular for sealing purposes, onto the lateral surfaces of the clamping member 40, which extend parallel to the tool axis.

[0055] As can be derived in particular from FIG. 4, the lubrication channel is arranged in an outer section of the clamping member 40 which is more distant from the tool axis 100 than an inner section of the clamping member 40. A dimension of the outer section of the clamping member 40 in radial direction to the tool axis 100 is thereby equal to a dimension of the inner section in radial direction. This means that only the outer section of the clamping member 40 and a corresponding section of the recess 21 being supplied with lubricant, so that lubricant is saved. At the same time, the lubrication of the clamping member 40 leads to a sealing of the second recess portion 21b against outside influences. These include, in particular, the inflow of material to be mixed, but also influences acting on the mixing shaft, for example during high-pressure cleaning of the latter.

[0056] In addition, the screw 41 fixing the clamping member 40 in the second recess portion 21b is also effectively protected against outside influences, so that the clamping member 40 can be loosened by simple means even after a longer service life of the mixing shaft 1 and the mixing blade 30 can be replaced particularly easily.

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

[0058] Alternatively, protective elements 70 can also be provided in a radially outer region of the clamping member 40, covering the lubricant receptacle 43 and the through hole 42 only, for example in the form of one or more plugs (see FIG. 2).

REFERENCE NUMBERS

[0059] 1 mixing shaft [0060] 20 tool holder [0061] 21 recess [0062] 21a first recess portion [0063] 21b second recess portion [0064] 22 thread opening [0065] 23 back wall [0066] 24 side wall [0067] 30 mixing blade [0068] 31 mixing blade portion [0069] 40 clamping member [0070] 40a first side of clamping member [0071] 40b second side of clamping member [0072] 41 screw [0073] 42 through hole [0074] 43 lubricant channel [0075] 44a first section of lubricant channel [0076] 44b second section of lubricant channel [0077] 50 release device [0078] 60 seal [0079] 70 protective element [0080] 80 pin [0081] 100 tool axis