Abstract
The invention relates to a scraper bar (20) for a scraper blade (68) of a road milling machine, having a carrier (10) that comprises a front side and a rearward installation surface (17), the carrier (10) comprising a cutting-element receptacle (13), cutting elements (30) being held, serially arranged along a longitudinal axis (L) extending in a width direction of the carrier (10), on or in the cutting-element receptacle (13), and the cutting elements (30) comprising a cutting edge (35.1) that transitions indirectly or directly into a rake surface (35). In order to improve the working result, provision is made according to the present invention that at least for some of the cutting elements (30), the cutting edge (35.1) is set at least locally not parallel to the longitudinal axis (L).
Claims
1. A scraper bar for a scraper blade of a road milling machine, the scraper bar comprising: a carrier including a front side, a rear-side installation surface, and a cutting-element receptacle; and a plurality of cutting elements serially arranged along a longitudinal axis extending in a width direction of the carrier on the cutting-element receptacle, each of the cutting elements including a cutting edge that transitions indirectly or directly into a rake surface; wherein the cutting edge of at least some of the cutting elements extends along the width direction and is at least partially set at an inclination angle not parallel to the longitudinal axis.
2. The scraper bar of claim 1, wherein: at least some of the cutting elements include two of the cutting edges, the two cutting edges being at an angle to one another, and the two cutting edges each being at least partially set at an inclination angle not parallel to the longitudinal axis.
3. The scraper bar of claim 1, wherein: at least some of the cutting elements include two limbs at an angle to one another, each of the two limbs including one of the cutting edges at least partially set at an inclination angle not parallel to the longitudinal axis.
4. The scraper bar of claim 1, wherein: at least some of the cutting elements include a secondary cutting edge extending transversely to the cutting edge.
5. The scraper bar of claim 1, wherein: at least some of the cutting elements include abutment surfaces, the serial arrangement of the cutting elements being provided by abutment of the abutment surfaces of adjacent cutting elements with one another; and the cutting edge of each of the cutting elements extends in a region between the abutment surfaces of the respective cutting element.
6. The scraper bar of claim 5, wherein: the cutting edge of each of the cutting elements extends to the abutment surfaces of the respective cutting element.
7. The scraper bar of claim 1, wherein: at least some of the cutting elements include two of the rake surfaces, the two rake surfaces adjoining one another indirectly or directly at a secondary cutting edge of the respective cutting element; and the two rake surfaces are at a roof-shaped angle to one another.
8. The scraper bar of claim 1, wherein: the plurality of cutting elements serially arranged along the longitudinal axis are arranged such that the cutting edges form a zigzag-shaped structure.
9. The scraper bar of claim 1, wherein: the plurality of cutting elements serially arranged along the longitudinal axis are arranged such that the cutting edges form a sawtooth-shaped structure.
10. The scraper bar of claim 1, wherein: the inclination angle of the cutting edges is in an angle range between 2 degrees and 28 degrees with respect to the longitudinal axis.
11. The scraper bar of claim 10, wherein: the angle range is between 10 degrees and 20 degrees.
12. The scraper bar of claim 1, wherein: the carrier includes a bottom surface adjacent to the cutting elements, the bottom surface extending rearward relative to the cutting edges; and the scraper bar includes one or more skid runners arranged on the bottom surface, the skid runners being made of a hard material harder than the carrier.
13. The scraper bar of claim 12, wherein: the bottom surface of the carrier has one or more receptacles recessed into the bottom surface, and each of the one or more skid runners is at least partly received in a respective one of the receptacles.
14. The scraper bar of claim 12, wherein: the carrier is configured such that when the scraper bar is installed on a scraper blade of a milling machine, the bottom surface of the carrier is inclined rearwardly upward with respect to a horizontal line.
15. The scraper bar of claim 1, wherein: the carrier includes an extension projecting rearward beyond the rear-side installation surface, the extension including a support surface such that the rear-side installation surface and the support surface enclose an angle.
16. The scraper bar of claim 1, wherein: the cutting-element receptacle includes a plurality of elevations, and at least some of the cutting elements include a depression, each of the elevations engaging a respective one of the depressions.
17. The scraper bar of claim 16, wherein: the cutting-element receptacle is assembled from a plurality of sub-receptacles, each sub-receptacle including at least one of the elevations.
18. The scraper bar of claim 1, wherein: the cutting-element receptacle includes a plurality of depressions, and at least some of the cutting elements include an elevation, each of the elevations engaging a respective one of the depressions.
19. The scraper bar of claim 18, wherein: the cutting-element receptacle is assembled from a plurality of sub-receptacles, each sub-receptacle including at least one of the depressions.
20. The scraper bar of claim 1, wherein: the cutting-element receptacle includes a flat placement surface extending along the longitudinal axis; and the cutting elements are each joined to the placement surface with a solder material.
21. The scraper bar of claim 1, wherein: the carrier has a width parallel to the longitudinal axis, a height perpendicular to the longitudinal axis, and a depth perpendicular to the width and the height, wherein the width is greater than the height and the width is greater than the depth.
22. The scraper bar of claim 1, wherein: the carrier includes receptacles defined through the rear-side installation surface for receiving fasteners for attaching the carrier to a scraper blade.
23. The scraper bar of claim 22, wherein: the front side of the carrier includes a scraper surface extending generally parallel to the rear-side installation surface; and the receptacles penetrate the scraper surface and the rear-side installation surface.
24. The scraper bar of claim 1, wherein: at least some of the cutting edges of the cutting elements lie in one plane.
25. The scraper bar of claim 1, wherein: at least some of the rake surfaces of the cutting elements are arranged parallel to one another.
26. The scraper bar of claim 1, in combination with: a height-adjustable scraper blade for a road milling machine; and a plurality of additional scraper bars, the scraper bars all being mounted on an underside of the scraper blade.
Description
BRIEF DESCRIPTION OF THE DRAWINGS
(1) The invention will be explained in further detail below with reference to exemplifying embodiments depicted in the drawings, in which:
(2) FIG. 1 is a side view of a road milling machine;
(3) FIG. 2 is a side view of a milling unit of the road milling machine according to FIG. 1;
(4) FIG. 3 is a vertical section of the milling unit according to FIG. 2;
(5) FIGS. 4 and 5 are perspective depictions of a first exemplifying embodiment of a scraper bar;
(6) FIG. 6 is a perspective depiction of a cutting element of the scraper bar according to FIGS. 4 and 5;
(7) FIG. 7 is a perspective depiction of a corner cutting element for the scraper bar according to FIGS. 4 and 5;
(8) FIG. 8 is a perspective view from below of a second variant embodiment of a scraper bar;
(9) FIG. 9 is a side view of the scraper bar according to FIG. 8;
(10) FIG. 10 is a perspective view of a third variant embodiment of a scraper bar;
(11) FIG. 11 is a side view of the scraper bar according to FIG. 10; and
(12) FIG. 12 is a view from below of the scraper bar according to FIGS. 10 and 11.
DETAILED DESCRIPTION
(13) FIG. 1 is a side view of a road milling machine 50. Road milling machine 50 possesses a chassis 51 that is carried by four propelling units 55. Two front propelling units 55 and two rear propelling units 55 are provided. Each propelling unit 55 is coupled to chassis 51 via a lifting column 54. Chassis 51 can be displaced in height with respect to propelling units 55 via lifting columns 54. Propelling units 55 are embodied in the present case as crawler track units. Chassis 51 furthermore carries a control cabin 52 for a machine operator. Control elements for road milling machine 50 are arranged here so that the machine driver can operate and drive road milling machine 50. A milling unit 60 is arranged between propelling units 55. A receiving belt 56 is associated with milling unit 60. The material milled off by milling unit 60 can be transported away via the receiving belt. Adjacently to receiving belt 56, the milled-off material falls onto a conveyor device 53. Conveyor device 53 can encompass a circulating conveyor belt. The milled material is loaded onto a truck by means of conveyor device 53.
(14) The configuration of milling unit 60 is depicted in more detail in FIGS. 2 and 3. As these drawings show, milling unit 60 comprises a milling drum 61. Milling drum 61 possesses a milling drum tube. Bit holders or quick-change bit holder systems 62 are mounted on the outer surface of the milling drum tube. When quick-change bit holder systems 62 shown in FIGS. 2 and 3 are used, a lower part of the quick-change bit holder system is mounted on the surface of the milling drum tube, for example bolted fixedly thereonto. An upper part, for example a bit holder, can be joined replaceably to the lower part. The bit holder possesses a bit receptacle. A milling bit 63 can be mounted replaceably in the bit receptacle. Milling drum 61 described above can be received rotatably in a milling drum housing 64. Milling drum 61 is driven by a drive unit of road milling machine 50.
(15) Milling drum housing 64 preferably surrounds milling drum 61 on all sides with the exception of its lower side. Milling unit 60 accordingly possesses two side panels 65 that are arranged in the region of the longitudinal ends of milling drum 61. These side panels 65 extend in the travel direction of road milling machine 50, which corresponds to the advance direction indicated in the drawings. Side panels 65 can be displaced as to height, i.e. vertically, separately from one another via a respective displacement mechanism 67. Side panels 65 comprise runners 66 at the bottom. Side panels 65 are set, with these runners 66, on the surface of the roadway during milling operation.
(16) Arranged in front of milling drum 61 in the travel direction is a front panel of milling drum housing 64, which panel comprises a passage. A physical connection between receiving belt 56 and milling drum 61 is created via the passage. Milling drum housing 64 is closed off at the top by a top panel. A rear panel is arranged at the rear. A scraper blade 68 is arranged at the lower end of the rear panel. Scraper blade 68 comprises a lower horizontal edge that proceeds, in FIG. 3, in a depth direction into the image plane.
(17) During milling operation, milling drum 61 is set onto the surface of the roadway that is to be worked. This is done by displacing lifting columns 54; milling drum 61 then rests with its lower side on the roadway surface. When a rotational motion is then imparted to milling drum 61, it mills off the surface of the roadway using milling bits 63. Quick-change bit holder systems 62 are positioned in the form of clearing and loading helices on the surface of milling drum 61. The milled material is transported by these clearing and loading helices to a predetermined location on milling drum 61, for example to the center of the milling drum, where ejectors of milling drum 61 are arranged. These throw the milled material onto receiving belt 56 so that it can be transported out of the working region. Scraper blade 68 does not, however, sit directly with its lower edge 68.1 on the roadway surface; instead, scraper bars 20different variants of which are shown in FIGS. 4 to 14are installed there. Those Figures will be discussed below.
(18) Scraper bars 20 have a carrier 10. The latter can be constituted, for example, from a steel material. Carrier 10 can be embodied, for example, as a forged part as shown in FIGS. 4 and 5. It is also possible for carrier 10 to be embodied as a milled part. Cutting elements 30 of scraper bar 20 are mounted on carrier 10. Cutting elements 30 are made of a hard material. It is conceivable to use metal carbide or ceramic as a hard material. Cutting elements 30 are preferably joined intermaterially to carrier 10; for example, it is conceivable for cutting elements 30 to be soldered to carrier 10. It is furthermore advantageous if, in addition or alternatively to a selected type of join, for example an intermaterial join, cutting elements 30 are also joined in positively engaging fashion to carrier 10.
(19) FIG. 4 shows, by way of example, a carrier 10. The latter comprises at the front a scraper surface 11, and at the rear an installation surface 17. Scraper surface 11 can be embodied parallel to installation surface 17. As FIG. 4 shows, one or several bolt receptacles 12 can be provided in the carrier. These bolt receptacles 12 penetrate through both scraper surface 11 and installation surface 17, and are thus embodied as through holes. A cutting-element receptacle 13 is arranged in the region of the lower horizontal edge of carrier 10. Cutting-element receptacle 13 is arranged with a setback to the rear with respect to scraper surface 11. Carrier 10 can have a cuboidal structure, having a longitudinal axis L that extends in a width direction. Carrier 10 has a component height, perpendicular to longitudinal axis L, that is considerably less than the component width. Carrier 10 furthermore has a component depth that once again is less than the component height. A cutting-element receptacle 13 can extend along longitudinal axis L.
(20) As also shown in FIG. 4, cutting-element receptacle 13 is embodied in segmented fashion. It accordingly comprises sub-receptacles 13.1. Sub-receptacles 13.1 each have support surfaces 13.2, 13.3. These support surfaces 13.2, 13.3 are arranged at an angle to one another. Support surfaces 13.2, 13.3 thus form elevations 13.5 that face toward the region of scraper surface 11. Facing away from scraper surface 11, support surfaces 13.2, 13.3 comprise transitions 13.4 that are embodied in set-back fashion. Cutting-element receptacle 13 also comprises a wall 14. The latter can be arranged, for example, perpendicularly to scraper surface 11 or at any other angle with respect to said scraper surface 11. In the case of scraper bar 20 shown in FIGS. 4 and 5, a corner receptacle 15 is provided at one of the longitudinal ends of cutting-element receptacle 13. The corner receptacle forms a support segment 15.1 that can be embodied in the form of a support surface. Corner receptacle 15 furthermore comprises connecting surfaces 15.2. Adjacently to corner receptacle 15, cutting-element receptacle 13 continues in the component height direction. In the depth direction, an adjoining surface 16 adjoins cutting-element receptacle 13 below cutting-element receptacle 13. This surface can extend perpendicularly to scraper surface 11 or to installation surface 17. Advantageously, adjoining surface 16 can also extend at an angle of more than 270 with respect to scraper surface 11.
(21) Be it noted at this juncture that the configuration features of carrier 10 explained above with reference to FIG. 4 are intended to apply not only to the embodiment according to FIGS. 4 to 7 of a scraper bar 20. These statements are instead intended to apply also to the other variant embodiments of scraper bars 20 described below, or to other scraper bars 20 according to the present invention.
(22) Cutting elements 30 can be mounted on cutting-element receptacle 13. Cutting elements 30 are depicted in more detail in FIG. 6. As is evident from that depiction, cutting elements 30 have two limbs 33 that are at an angle to one another. Limbs 33 terminate at the bottom in flank surfaces 31. A secondary cutting edge 36 is arranged at the front in connecting region 32 in which limbs 33 meet one another. This secondary cutting edge 36 connects two rake surfaces 35 that are at an angle to one another. Rake surfaces 35 form a roof-shaped geometry. Cutting edges 35.1 are formed in the transition region between flank surfaces 31 and rake surfaces 35. Cutting edges 35.1 can be arranged so that they are guided as far as connecting region 32. Cutting edges 35.1 are preferably embodied so that they meet one another in the connecting region. It is also conceivable for cutting edges 35.1 that meet one another to meet at secondary cutting edge 36. As is further evident from FIG. 6, rake surfaces 35 transition via segments 37 into abutment surfaces 34. The two oppositely located abutment surfaces 34 are preferably parallel to one another.
(23) Cutting elements 30 can be mounted on sub-receptacles 13.1 of cutting-element receptacle 13 through the intermediary of an intermaterial join, for example solder material or adhesive material. For that purpose, cutting elements 30 are placed with their limbs 33 onto support surfaces 13.2, 13.3 of cutting-element receptacle 13. Those sides of cutting element 30 which are located opposite flank surfaces 31 are pushed against wall 14. Exact positioning and alignment of cutting elements 30 is thereby achieved. Flank surface 31 preferably transitions flush into adjoining surface 16. Cutting elements 30 are serially arranged along longitudinal axis L, and abutment surfaces 34 of the adjacent cutting elements 30 abut against one another. Abutment surfaces 34 do not need to meet one another directly. It is instead preferably also conceivable for intermaterial joins, for example a solder join or an adhesive join, to be arranged between abutment surfaces 34. A corner cutting element 40 can be inserted into corner receptacle 15. Corner cutting element 40 is shown in FIG. 7. As is evident from this depiction, corner cutting element 40 comprises abutment surfaces 41, 42 at an angle to one another. A placement surface 44 is provided on the bottom, and a rake surface 45 oppositely from it. A connecting surface 46 is provided in the region in which the two abutment surfaces 41, 42, located at an angle to one another, meet one another. Connecting surface 46 can also merely comprise a radius. Oppositely from connecting surface 46, deflection surface 45 possesses a cutting edge 47. This cutting edge 47 is configured in a curved shape in the present instance. A flank surface 43 adjoins cutting edge 47. As in the exemplifying embodiment shown, that flank surface 43 can extend from cutting edge 47 as far as placement surface 44. It is also conceivable for flank surface 43 to extend only over a sub-region. Flank surface 43 can preferably be embodied as a convexly curved wall, as in the exemplifying embodiment shown.
(24) FIG. 5 shows the completely installed scraper bar 20. As is evident from this depiction, the cutting elements form a zigzag-shaped cutting edge in the region of the underside of scraper bar 20. With a corresponding conformation of cutting elements 30 it would also be possible to implement a wave-shaped cutting edge if cutting edges 35.1 of cutting element 30 were not set at an angle to one another but instead were arranged in a wave shape. In this case it is recommended that rake surfaces 35 also be arranged in a wave shape with respect to one another.
(25) FIGS. 8 and 9 show a further variant embodiment of a scraper bar 20 in which a sawtooth-shaped cutting edge is implemented. As FIG. 8 shows, in contrast to the configuration according to FIGS. 4 to 7, a segmented cutting-element receptacle 13 having sub-receptacles 13.1 is not used. What is present here instead is a cutting-element receptacle 13 that is continuous along longitudinal axis L. It is conceivable here as well, of course, to implement a segmented cutting-element receptacle 13 having sub-receptacles 13.1. Cutting elements 30 are serially arranged in cutting-element receptacle 13. Cutting elements 30 again form a bottom-side flank surface 31 that transitions via a cutting edge 35.1 into rake surfaces 35. Oppositely from flank surface 31, cutting element 30 again possesses an abutting surface for abutment against a wall 14 of cutting-element receptacle 13. Cutting elements 30 form, at oppositely located sides, abutment surfaces 34 by way of which they are serially arranged. Cutting edges 35.1 of cutting elements 30 do not extend parallel to longitudinal axis L but instead are set at an angle with respect thereto.
(26) With the variant embodiment according to FIGS. 8 to 9, a rear-side extension 18 is provided on carrier 10. Extension 18 projects beyond installation surface 17 and is joined in one piece to carrier 10. Extension 18 forms a support surface 18.1. Installation surface 17 and support surface 18.1 enclose an angle. In the region of the underside, carrier 10 possesses receptacles 16.1 that are recessed into the underside of carrier 10. Skid runners 70 made of hard material are inserted into receptacle 16.1. Metal carbide, ceramic, or another hard substance can again be used as a hard material. Skid runners 70 are preferably held intermaterially in receptacles 16. They are arranged so that they project a little way beyond the underside of adjoining surface 16, as shown in FIG. 9. Skid runners 70 thus provide wear protection for the underside of carrier 10. The use of a rearward extension 18 and of the above-described skid runners 70 is not limited to the present exemplifying embodiment. These conformations can instead also be provided, individually or in combination, in the context of other exemplifying embodiments and in particular as desired in conjunction with the invention.
(27) As FIG. 9 further shows, cutting elements 30 are inserted into cutting-element receptacle 13.1 in such a way that flank surface 31 is embodied with an inclination with respect to the bottom horizontal line extending parallel to the advance direction. In particular, the bottom horizontal line and flank surface 31 enclose an acute angle. This feature as well can be utilized in all embodiments of the invention.
(28) FIGS. 10 to 12 show an exemplifying embodiment of the invention which is embodied analogously to the exemplifying embodiment according to FIGS. 8 and 9, so that reference may be made to the statements above. The only difference between the two embodiments is that a rear-side extension 18 is not utilized in the context of scraper bar 20 according to FIGS. 10 to 12. As FIG. 11 shows and as has been described above with reference to FIGS. 8 and 9, the bottom-side adjoining surface 16 is inclined with respect to the bottom horizontal line (angle ). When scraper bar 20 is in the installed position, the front-side scraper surface 11 is slightly tilted with respect to the vertical plane which is perpendicular to the advance direction (angle ). It is apparent from FIG. 12 that cutting edges 35.1 of cutting elements 30 are, in accordance with the invention, at an angle () with respect to longitudinal axis L. It is also evident from FIG. 12 that in the installed position, scraper bar 20 is oriented so that advance direction V extends transversely to longitudinal extent L. Cutting edges 35.1 of cutting elements 30 are accordingly also set with respect to the advance direction at an angle which is greater than 90.
(29) Skid runners 70 that are inserted into the underside of carrier 10 are also used in the exemplifying embodiment according to FIGS. 10 to 12.
(30) Scraper bars 20 described above can be installed on lower edge 68.1 of a scraper blade 68, as has been described above. Several scraper bars 20 are installed next to one another in order to populate lower edge 68.1 at least in part. It is conceivable for physically identical scraper bars 20 always to be installed next to one another on scraper blade 68. It is also possible for scraper bars 20 having corner cutting elements 40 to be installed at the longitudinal ends of scraper blade 68. FIGS. 4 to 7 show an exemplifying embodiment of an end-located scraper bar 20 of this kind. The step that occurs in the milled pattern and is produced as a consequence of milling drum 61 is also reworked with such end-located scraper bars 20, and corner cutting elements 40 ensure a clean and exact termination. It is therefore conceivable in the context of the invention to utilize a scraper blade 68 in which scraper bars 20 are serially arranged, the two last scraper bars 20 of that series comprising a corner cutting element 40. It is also conceivable, in the context of those two, or one, end-located scraper bar(s), for at least one cutting element 30 to adjoin corner cutting element 40 on both sides, as shown e.g. by FIG. 5.
