AU2014218487B2 - Ejector or ejector unit for a road milling machine or the like - Google Patents

Abstract

The invention relates to an ejector, in particular for a road milling machine, with which maintenance outlay can be considerably simplified. 5724514_1 (GHMatters) P87883.AU.1 ANDREAS WO 2010/108743 PCT/EP2OI 0/052290 FFig. 2

Description

EJECTOR OR EJECTOR UNIT FOR A ROAD MILLING MACHINE OR THE LIKE The invention relates to an ejector, in particular for the milling drum of a road milling machine or a surface miner, etc. Road milling machines usually comprise a milling tube on whose surface are mounted a plurality of bit holders. The bit holders are usually part of a bit holder changing system that also encompasses a base part. The base part is welded onto the surface of the milling tube, and replaceably receives the bit holders. The bit holder serves for mounting of a cutting bit, usually a round-shaft cutting bit, as known e.g. from P 37 01 905 Al. The bit holders are arranged on the surface of the milling tube so as to yield spiral-shaped helices. The helices proceed from the edge region of the milling tube and rotate toward the center of the milling tube. The respective helices that proceed from the oppositely located edge regions therefore meet at the center of the milling tube. One or more ejectors are also then arranged in this region. The helices convey to the ejectors the material removed by the cutting bits. The ejectors then transport it out of the working region of the milling tube. The ejectors are subject to severe abrasive attack, and must therefore be regularly checked and replaced. For this, the ejector welded onto the milling tube must be detached and a new one welded on. Attention must be paid to the exact positioning and alignment of the ejector in order to achieve ideal discharge performance. This replacement work in the confined working area of the milling tube is laborious. It would be advantageous if the present invention would make available an improved ejector that enables simple machine maintenance. 1 5724514_1 (GHMatters) P87883.AU.1 ANDREAS The present invention provides in a first aspect an ejector being suitable for mounting on a carrier of a milling drum of a road milling machine or a surface miner or the like, the ejector comprising: a conveying surface at a front side; and a support surface at a rear side, the support surface having a convexly shaped or crowned portion for engagement with a concavely shaped or hollowed receiving portion of the carrier. The ejector may comprise at least one mounting receptacle for receiving a bolt for mounting the ejector on the carrier. The support surface may comprise at least one mounting or securing extension for positioning the ejector relative to the carrier and may be arranged such that the ejector is reversibly mountable on the carrier in at least two mounting positions. Further, the support surface may be arranged such that the ejector is reversibly mountable on the carrier in at least two mounting positions in which respective regions of the ejector face away from the milling drum. The conveying surface may have a hollowed or concave and/or scoop-like cross sectional shape. The ejector may be curved along at least a part of a length of the ejector such that the conveying surface is concave or hollowed and/or scoop-like lengthwise and the support surface is convex or crowned lengthwise. The mounting or securing extension may be lengthwise extending and/or the mounting or securing extension may be widthwise extending. The support surface may, at least at the convexly shaped or crowned portion for engagement with the carrier, be symmetrical about a lengthwise centre line of the 2 5724514_1 (GHMatters) P87883.AU.1 ANDREAS mounting or securing extension in a widthwise direction and/or the support surface may at least at that portion be symmetrical about a widthwise centre line of the mounting or securing extension in a lenghtwise direction. The mounting receptacle may comprise at least one of: a protruding mounting or securing extension and a recessed securing receptacle. The ejector may be generally rectangular and the support surface may, at least at the convexly shaped or crowned portion for engagement with the carrier, be symmetrical about a plane that is perpendicular to at least a portion of the length of the ejector. Alternatively or additionally, the ejector may be generally rectangular and the support surface may, at least at the convexly shaped or crowned portion for engagement with the carrier, be symmetrical about a plane that is perpendicular to at least a portion of the width of the ejector. The ejector may be reversibly mountable on the carrier in a first mounting position and a second mounting position and the ejector may be rotated about a rotation axis that is normal to a portion of the support surface by approximately 180 when mounted in the first mounting position compared with the second mounting position. The support surface may at least at the convexly shaped or crowned portion for engagement with the carrier, be symmetrical about the rotation axis. The ejector may symmetrical about the rotation axis. The at least one mounting receptacle may have an axis and that axis may be parallel to the rotation axis. The at least one mounting or securing extension may have an axis of symmetry and that axis may be parallel to, or may coincide with, the rotation axis. 3 5724514_1 (GHMatters) P87883.AU.1 ANDREAS The at least one mounting receptacle may comprise a bolt hole defined through the ejector body between the front conveying surface and the rear support surface. The bolt hole may penetrate through a portion of the mounting or securing extension. An axis of the at least one mounting receptacle may lie on a lengthwise centre line of the mounting or securing extension. The at least one receptacle may open toward the conveying surface of the ejector into a bolt head receptacle in which a bolt head is positionable in a manner such that the bolt head is not rotatable.The bolt head receptacle may be a polygonal shape fastener head receptacle defined in a recess. One or more stiffening ribs may be arranged on the support surface. The mounting receptacle may be arranged such that displacement of the ejector for at least one direction in a plane transverse to a feed direction can be limited in a positively engaged fashion. The mounting or securing extension may be arranged such that displacement of the ejector for at least one direction in a plane transverse to a feed direction can be limited in a positively engaged fashion. The conveying surface may comprise one or more depressions. At least one wear protection element, made of a material more wear-resistant than the conveying surface, may be arranged in the region of the conveying surface. The wear protection element may be provided in the form of a hard-material element or a welded material. 4 5724514_1 (GHMatters) P87883.AU.1 ANDREAS The present invention provides in a second aspect a unit for a road milling machine or surface miner, the unit comprising: the ejector in accordance with the first aspect of the present invention; a carrier that carriers the ejector; and a milling drum on which the carrier is mounted. The present invention provides in a third aspect an ejector, such as for a drum of a road milling machine or a surface miner, comprising: a conveying surface that is directed in a feed direction when the ejector is in use; a rear side in use facing away from the conveying surface, the rear side forming a mounting side having at least one support surface; and mounting receptacle, such as at least one of: a screw receptacle and a mounting extension.. The ejector typically is suitable for a milling drum of a road milling machine or a surface miner. With this mounting side, the ejector can be placed onto a component mounted on the milling tube, for example onto a carrying part welded thereon. By way of the at least one support surface of the carrying part, the loads occurring during tool use are reliably dissipated at least in part. The ejector is equipped with a mounting receptacle or mounting extension, so that it is replaceably mountable. In this fashion it can easily be changed in the event of damage or wear. According to a preferred variant embodiment of the invention, provision may be made that the conveying surface of the ejector is arranged transversely to the feed direction of the ejector unit, and is at least locally embodied in concave fashion or is assembled, in the hollowed region, from line segments and/or curve segments. The concave or hollowed conformation enables a scoop-like geometry that improves the discharge rate. 5 5724514_1 (GHMatters) P87883.AU.1 ANDREAS If provision is made that one or more depressions are introduced into the conveying surface, material removed during tool use can become deposited in the depressions. A "natural" wear protection layer forms there. According a variant of the invention, provision may be made that at least one screw receptacle is used as a mounting receptacle, and that the screw receptacle opens, toward the front side of the ejector, into a screw head receptacle in which a screw head of a mounting screw is at least locally nonrotatably receivable. Rapid and problem-free ejector replacement is possible with the screw connections. Countersunk or partly countersunk reception of the screw head prevents abrasive attack on the countersunk head region. In addition, loosening of the screw at this point is prevented. To allow the ejector to be reliably braced on a carrying part, provision may be made that at least one protruding securing extension, or a recessed securing receptacle, is arranged on the side facing away from the conveying surface. Transverse forces that occur can then be transferred, in particular, in positively engaged fashion from the ejector into the carrying part. This is possible in particular when provision is made that by means of the at least one securing extension or the at least one securing receptacle, any displacement of the ejector in a plane transverse to the feed direction can be limited in positively engaged fashion. If the conformation of the ejector is such that one or more shaped-on stiffening ribs are arranged on the rear side facing away from the conveying surface, a sufficiently rigid ejector can then be designed with little material outlay. Provision may be made according to an embodiment of the present invention that the screw receptacle is guided through the securing extension or securing receptacle. The carrying part is then utilized for a sufficient clamping length of the mounting screw. 6 5724514_1 (GHMatters) P87883.AU.1 ANDREAS A preferred configuration of the invention is such that the mounting side is embodied in such a way that the ejector is installable in different operating positions. The ejector may, in particular, be embodied in mirror-symmetrical fashion, or may be embodied in the region of a mounting side in such a way that it enables installation reversibly in two different operating positions. Also conceivable is an ejector that enables three or four different operating positions. This is based on the recognition that the ejector becomes worn substantially on its region facing away from the milling tube. Once the worn state is achieved there, the ejector is removed and put back on having been rotated, for example, 180 degrees. A preferred configuration of the invention is such that the mounting side comprises a convex or crowned or spherical mounting portion for contact against a concave or hollowed receiving portion of a carrier. This connection creates a large connecting surface that ensures good energy transfer even when the conveying surface is asymmetrically loaded. A further improvement in service life is achieved by the fact that at least one wear protection element, made of a material more wear-resistant than the conveying surface, is arranged in the region of the conveying surface. In this context, provision may be made in particular that the wear protection element is constituted by a hard-material element, for example carbide or ceramic, or by an applied coating, for example a hardfacing. In accordance with a fourth aspect of the present invention there is provided a unit of a road milling machine or surface miner, the unit comprising the ejector of the first aspect of the present invention and a drum arranged for mounting of the ejector. The present invention provides in a fifth aspect an ejector for a milling drum of a road milling machine or a surface miner or the like, the ejector being suitable for mounting on the milling drum using a carrier and comprising: a conveying surface, 7 5724514_1 (GHMatters) P87883.AU.1 ANDREAS a support surface at a rear side that in use faces towards the carrier and in a direction that is opposite to that of the conveying surface, the support surface comprising a mounting receptacle for engagement with a bolt or with a mounting extension to position the ejector relative to the carrier and being arranged such that the ejector is reversibly mountable on the carrier in at least two mounting positions in which respective regions of the ejector face away from the milling drum; wherein the ejector, when in use and mounted on the milling drum, becomes worn at a region that is facing away from the milling drum and the ejector can then be rotated such that another region of the ejector is facing away from the milling drum. The present invention provides in a sixth aspect a unit for a road milling machine or surface miner, the unit comprising: the ejector of the first or second aspect of the present invention; a carrier that carriers the ejector; and a milling drum on which the carrier is mounted. The invention will be more fully understood from the following description of embodiments of the invention. The description is provided with reference to the accompanying drawings, in which: FIG. 1 is a front view of a milling drum of a road milling machine; FIG. 2 is a side view of the milling drum according to FIG. 1; FIG. 3 shows the view according to FIG. 2, enlarged and with a slightly modified depiction; FIG. 4 is a perspective front view of an ejector unit; 8 5724514_1 (GHMatters) P87883.AU.1 ANDREAS FIG. 5 is a perspective rear view of the ejector unit according to FIG. 4; FIG. 6 is a perspective rear view of a carrier of the ejector unit according to FIG. 5; FIG. 7 is a perspective view of the carrier according to FIG. 6; FIG. 8 is a perspective front view of an ejector of the ejector unit according to FIG. 6; FIG. 9 is a perspective rear view of the carrier according to FIG. 8; FIG. 10 is a perspective rear view of a second embodiment of an ejector unit having an ejector and a carrier; and FIG. 11 is a perspective front view of the arrangement according to FIG. 10. FIG. 1 shows a milling drum having a cylindrical milling tube 10 onto whose drum surface 10.1 are welded a plurality of base parts 11 of bit holder changing systems. Base parts 11 carry replaceable bit holders 12. A cutting bit 13, specifically a round shaft cutting bit, is replaceably received in each bit holder 12. Base parts 11 are arranged with respect to one another so that they form a helix, specifically a transport helix. The helix rotates, proceeding from the side of milling tube 10 on drum surface 10.1, toward the milling tube center formed between the two sides. For better clarity, only some of the bit holder changing systems are depicted in FIGS. 1 and 2. Dashed lines that represent the center longitudinal axis of cutting bits 13 are shown as substitutes for the bit holder changing systems (not shown). As is evident from these lines, multiple transport helices are located on either side of the milling tube center. The transport helices meet in pairs in the region of the milling tube center. As is evident from FIG. 1, at least one respective ejector unit is arranged there. FIG. 3, as compared 9 5724514_1 (GHMatters) P87883.AU.1 ANDREAS with the depiction in FIG. 2, does not show the bit holder changing systems, redirecting attention to the ejector unit. As is evident from this depiction, the ejector unit is constituted by a carrying part 30 and an ejector 20. FIGS. 4 and 5 show the ejector unit in isolation. Firstly the design of carrying part 30 will be explained with reference to FIGS. 6 and 7. Said part comprises a mounting foot 31 that forms on its underside a mounting surface 33. With this, carrying part 30 can be placed onto drum surface 10.1 and welded at the sides. Shaped onto mounting foot 31 is an upwardly projecting support part 35 that forms a rear side 36. Mounting foot 31 is widened by means of an extension 32 over rear side 36, so that it forms a wide mounting surface 33 having a large support spacing. The widened cross section produced by extension 32 furthermore brings about a reinforcement of the highly stressed transition region between mounting foot 31 and carrying part 35. A further widening of mounting surface 33 is achieved with a front-side protrusion 34 that, like extension 32, extends over the entire width of carrying part 30. Carrying part 30 comprises on the front side a support surface 37 that extends over the front side of carrying part 35 and also over part of mounting foot 31. This embodiment of support surface 37 enables strength-optimized bracing of ejector 20. Two receptacles 37.1, 37.2 are inset into support surface 37. The two receptacles 37.1, 37.2 are recessed into support surface 37 so that they form trough-like hollows. Ejector 20 will be explained below with reference to FIGS. 8 and 9. It is embodied in plate-shaped fashion as a drop forged part, and is therefore particularly rigid. Ejector 20 comprises a front-side conveying surface 21. Said surface is equipped with recesses 21.1, 22. Located between recesses 21.1 are ribs that are at an angle to the vertical and are thus inclined toward the center of the ejector. The recesses receive removed material during operational use, thus forming a "natural" wear protector. A particularly good conveying rate is furthermore achieved by 10 5724514_1 (GHMatters) P87883.AU.1 ANDREAS the fact that conveying surface 21 is embodied in concave, and thus scoop-shaped, fashion. Recess 22 comprises two oblique surfaces 22.1 that are at an angle to conveying surface 21 and assist the conveying action. Located between the two recesses 22 is a thickened extension 23 that receives two screw receptacles 29 embodied as through holes. Screw receptacles 29 transition on the front side into hexagonal screw head receptacles 29.1. FIG. 9 shows the rear side of ejector 20. As is evident from this depiction, rib-like securing extensions 26.1, 26.2 project from ejector 20 on the rear side. Securing extensions 26.1 and 26.2 are adapted, in terms of their arrangement and dimensioning, to the arrangement and shape of receptacles 37.1 and 37.2 of carrier 30. Screw receptacles 29 are guided through securing extension 26.1. As is further evident from FIG. 9, stiffening ribs 27 are arranged in the rear-side corner regions of ejector 20. Said ribs are connected to the horizontal securing extension 26, thus yielding optimum energy dissipation. In order to mount ejector 20, it is placed with its rear side onto support surface 37 of carrier 30. Securing extensions 26.1, 26.2 then engage into the corresponding receptacles 37.1, 37.2. This results in a crosswise splining that prevents any displacement of ejector 20 with respect to carrier 30 in the axial and radial direction of milling tube 10. By way of this splined connection, large portions of the forces occurring during tool use can be dissipated. Screw receptacles 29, 36.1 of ejector 20 and of carrier 30 are in alignment, so that mounting screws 24 (see FIGS. 4 and 5) can be inserted through them. The screw head of mounting screws 24 is accommodated in screw head receptacle 29.1, where it is held nonrotatably. Preferably self-locking nuts 28 can be screwed onto mounting screws 24, and ejector 20 can thus be secured on carrier 30. 11 5724514_1 (GHMatters) P87883.AU.1 ANDREAS It is chiefly the radially projecting region of ejector 20 that wears during tool use. As is evident from FIGS. 8 and 9, ejector 20 is embodied symmetrically with respect to the center transverse plane. When the wear limit is reached, it can therefore be removed and put back on having been rotated 180 degrees. FIGS. 10 and 11 show a further variant embodiment of an ejector unit according to an embodiment of the present invention. Said unit once again encompasses an ejector 20 and a carrier 30. Ejector 20 again possesses a hollowed conveying surface 21 that faces in the processing direction, the hollow being recessed concavely in a direction opposite to the processing direction. Facing away from conveying surface 21, ejector 20 comprises on its rear-side mounting side 25 a mounting extension 20.1. The latter protrudes in block fashion oppositely to the processing direction. It possesses two screw receptacles that can be arranged in alignment with screw receptacles of carrier 30. Mounting screws 24 can be passed through the screw receptacles, and nuts 28 can be threaded onto their threaded studs. Ejector 20 is thereby fixedly clamped, in particular braced, against a support surface 37 of carrier 30. As is evident from the drawings, ejector 20 is equipped in the region of mounting side 25 with cutouts 20.2. Upper cutout 20.2 receives the heads of mounting screws 24 and thus protects them, behind conveying surface 21, from the abrasive attack of the removed material. Lower cutout 20.2 extends in skirt fashion over carrier 30 and protects it there. Ejector 20 is symmetrical with respect to the central transverse axis, and can therefore be mounted reversibly in two operating positions, rotated 180 degrees, on carrier 30. 12 5724514_1 (GHMatters) P87883.AU.1 ANDREAS

Claims (28)

1. An ejector being suitable for mounting on a carrier of a milling drum of a road milling machine or a surface miner or the like, the ejector being arranged for transporting material cut by cutting bits of the milling drum away from the milling drum, the ejector comprising: a conveying surface at a front side, at least a portion of the conveying surface having a generally concave and/or scoop-like shape ; and a support surface at a rear side, the support surface having a convexly shaped or crowned portion for engagement with a concavely shaped or hollowed receiving portion of the carrier.

2. The ejector of claim 1 comprising at least one mounting receptacle for receiving a bolt for mounting the ejector on the carrier.

3. The ejector of claim 1 or 2 wherein the support surface comprises at least one mounting or securing extension for positioning the ejector relative to the carrier.

4. The ejector of any one of the preceding claims, wherein the support surface is arranged such that the ejector is reversibly mountable on the carrier in at least two mounting positions.

5. The ejector of claim 4 wherein the support surface is arranged such that the ejector is reversibly mountable on the carrier in at least two mounting positions in which respective regions of the ejector face away from the milling drum.

6. The ejector of any one of the preceding claims wherein the ejector has a length and is curved along at least a portion of the length such that the conveying surface is concave or and/or scoop-like lengthwise and the support surface has a portion that is convexly curved lengthwise. 13 7578082_1 (GHMatters) P87883.AU.1

7. The ejector of claim 3 or any one of claims 4 or 5 when dependent on claim 3 wherein the ejector has a length and a width and wherein mounting or securing extension is lengthwise extending and/or the mounting or securing extension is widthwise extending.

8. The ejector of claim 7 wherein the ejector has a length and a width and wherein the support surface is, at least at the convexly shaped or crowned portion for engagement with the carrier, symmetrical about a lengthwise centre line of the mounting or securing extension in a widthwise direction and/or the support surface is least at that portion symmetrical about a widthwise centre line of the mounting or securing extension in a lenghtwise direction.

9. The ejector of claim 2 or any one of claims 3 to 8 when dependent on claim 2 wherein the mounting receptacle comprises at least one of: a protruding mounting or securing extension and a recessed securing receptacle.

10. The ejector of any one of the preceding claims wherein the ejector is generally rectangular and wherein the support surface is, at least at the convexly shaped or crowned portion for engagement with the carrier, symmetrical about a plane that is perpendicular to at least a portion of the length of the ejector.

11. The ejector of any one of the preceding claims wherein the ejector is generally rectangular and has a length and a width and wherein the support surface is, at least at the convexly shaped or crowned portion for engagement with the carrier, symmetrical about a plane that is perpendicular to at least a portion of the width of the ejector.

12. The ejector of any of the preceding claims wherein the ejector is reversibly mountable on the carrier in a first mounting position and a second mounting 14 7578082_1 (GHMatters) P87883.AU.1 position and wherein the ejector is rotated about a rotation axis that is normal to a portion of the support surface by approximately 180 when mounted in the first mounting position compared with the second mounting position.

13. The ejector of claim 12 wherein the support surface is, at least at the convexly shaped or crowned portion for engagement with the carrier, symmetrical about the rotation axis.

14. The ejector of claim 12 or 13 wherein the ejector is symmetrical about the rotation axis.

15. The ejector of claim 12or 13 when dependent on claim 2 wherein the at least one mounting receptacle has an axis and wherein that axis is parallel to the rotation axis.

16. The ejector of claim 12 or 13 when dependent on claim 3 wherein the at least one mounting or securing extension has an axis of symmetry and wherein that axis is parallel to, or coincides with, the rotation axis.

17. The ejector of claim 3 when dependent on claim 2 or anyone of claims 4 to 16 when dependent on claims 2 and 3 wherein the at least one mounting receptacle comprises a bolt hole defined through the ejector body between the front conveying surface and the rear support surface.

18. The ejector of claim 17 wherein the bolt hole penetrates through a portion of the mounting or securing extension.

19. The ejector of any one of claims 16 to 18 wherein an axis of the at least one mounting receptacle lies on a lengthwise centre line of the mounting or securing extension. 15 7578082_1 (GHMatters) P87883.AU.1

20. The ejector of any one of claims 17 to 19 wherein the at least one receptacle opens toward the conveying surface of the ejector into a bolt head receptacle in which a bolt head is positionable in a manner such that the bolt head is not rotatable.

21. The ejector of claim 20, wherein the bolt head receptacle is a polygonal shape fastener head receptacle defined in a recess.

22. The ejector of any one of the preceding claims, wherein one or more stiffening ribs are arranged on the support surface.

23. The ejector of claim 2 or any one of claims 3 to 22 when dependent on claim 2 wherein the mounting receptacle is arranged such that displacement of the ejector for at least one direction in a plane transverse to a feed direction can be limited in a positively engaged fashion.

24. The ejector of claim 3 or any one of claims 4 to 23 when dependent on claim 3 wherein the mounting or securing extension is arranged such that displacement of the ejector for at least one direction in a plane transverse to a feed direction can be limited in a positively engaged fashion.

25. The ejector of one of the preceding claims, wherein the conveying surface comprises one or more depressions.

26. The ejector of any one of the preceding claims, wherein at least one wear protection element, made of a material more wear-resistant than the conveying surface, is arranged in the region of the conveying surface. 16 7578082_1 (GHMatters) P87883.AU.1

27. The ejector of claim 26, wherein the wear protection element is provided in the form of a hard-material element or a welded material.

28. A unit for a road milling machine or surface miner, the unit comprising: the ejector of any one of the preceding claims; a carrier that carriers the ejector; and a milling drum on which the carrier is mounted. 17 7578082_1 (GHMatters) P87883.AU.1