Ejector unit for a road milling machine or the like

Abstract

The invention relates to an ejector unit, in particular for a road milling machine, having an ejector that is replaceably mounted on a carrier. In one aspect the ejector is curved in a scoop-like fashion. In another aspect the ejector is reversible upon the carrier to allow the ejector to be reversed after one wear surface is worn, thus presenting a new second wear surface.

Claims

1. A milling drum for a road milling machine, the milling drum comprising: a cylindrical milling tube rotatable about a rotational axis, the rotational axis defining an axial direction parallel to the rotational axis; a plurality of cutting bits mounted on the milling tube; and at least one ejector assembly mounted on the milling tube, the ejector assembly including: a carrier mounted on the milling tube, the carrier including first and second carrier mounting holes defined through the carrier, the carrier mounting holes being spaced apart in the axial direction; an ejector body having a length and a width, the length being greater than the width, the ejector body having a front conveying side and a rear mounting side, the front conveying side having first and second forward facing conveying surfaces adjacent lengthwise edges of the front conveying side, the first and second forward facing conveying surfaces being curved along at least part of the length of the ejector body, the ejector body including two body mounting holes defined through the ejector body from the front conveying side to the rear mounting side, the body mounting holes being spaced apart in the axial direction, and the body mounting holes being aligned with the carrier mounting holes and the ejector body being configured so that the ejector body can be reversibly mounted on the carrier in either of two mounting positions rotated 180 from each other about an ejector body rotational axis extending through the front conveying side and the rear mounting side; and first and second fasteners extending through the aligned carrier mounting holes and body mounting holes to mount the ejector body on the carrier.

2. The milling drum of claim 1, wherein: the ejector body has a lengthwise center line so that the lengthwise edges of the ejector body are symmetrical about the lengthwise center line.

3. The milling drum of claim 2, wherein: the body mounting holes have mounting hole axes intersecting with the lengthwise center line.

4. The milling drum of claim 1, wherein the ejector body rotational axis is normal to the rear mounting side.

5. The milling drum of claim 1, wherein: the first and second forward facing conveying surfaces are curved along at least a majority of the length of the ejector body.

6. The milling drum of claim 5, wherein: the first and second forward facing conveying surfaces are curved along the entire length of the ejector body.

7. The milling drum of claim 1, wherein: the first and second forward facing conveying surfaces are curved along at least a majority of the length of the ejector body; the axes of the mounting holes lie on a lengthwise center line of the ejector body; the front conveying side has defined therein a recess between the first and second forward facing conveying surfaces, the recess having a recess length and a recess width, the recess length being parallel to the length of the ejector body and being longer than the recess width; the first and second mounting holes communicate with the recess of the front conveying side; and at least a part of the recess is defined by a recess bottom located between two recess sides extending at widthwise oblique angles to the recess bottom.

8. An ejector unit for a milling drum of a road milling machine, the ejector unit comprising: a carrier including a mounting foot having a foot mounting surface shaped to be received on the milling drum, and a support portion extending upwardly from the mounting foot, the support portion including a forward facing support surface; and an ejector including a front conveying side and including a rear mounting side received against the forward facing support surface of the carrier, the ejector having a length and a width, the length being greater than the width, and the length extending transverse to the upwardly extending support portion; and wherein the carrier and ejector each include at least two mounting holes extending through the support portion of the carrier and through the ejector, the mounting holes through the ejector extending through the front conveying side and the rear mounting side, the mounting holes through the ejector being spaced apart along the length of the ejector and the ejector being configured so that the ejector can be reversibly mounted on the carrier in either of two mounting positions rotated 180 from each other about a rotational axis extending through the front conveying side and the rear mounting side; wherein the front conveying side includes first and second forward facing conveying surfaces adjacent lengthwise edges of the front conveying side, the first and second forward facing conveying surfaces being curved along at least part of the length of the ejector.

9. The ejector unit of claim 8, wherein the ejector has a lengthwise center line and the mounting holes have mounting hole axes intersecting the lengthwise center line.

10. The ejector unit of claim 8, wherein the rotational axis is normal to the rear mounting side.

11. The ejector unit of claim 8, wherein: the first and second forward facing conveying surfaces are curved along at least a majority of the length of the ejector.

12. The ejector unit of claim 11, wherein: the first and second forward facing conveying surfaces are curved along the entire length of the ejector.

13. The ejector unit of claim 8, wherein: the first and second forward facing conveying surfaces are curved along at least a majority of the length of the ejector; the axes of the mounting holes lie on a lengthwise center line of the ejector; the front conveying side has defined therein a recess between the first and second forward facing conveying surfaces, the recess having a recess length and a recess width, the recess length being parallel to the length of the ejector and being longer than the recess width; the first and second mounting holes communicate with the recess of the front conveying side; and at least a part of the recess is defined by a recess bottom located between two recess sides extending at widthwise oblique angles to the recess bottom.

14. An ejector for a road milling machine, comprising: an ejector body having a length and a width, the length being greater than the width, the body having a front conveying side and a rear mounting side, the front conveying side having first and second forward facing conveying surfaces adjacent lengthwise edges of the front conveying side, the first and second forward facing conveying surfaces being curved along at least part of the length of the ejector body; and first and second lengthwise spaced mounting holes defined through the ejector body between the front conveying side and the rear mounting side, the ejector body being reversibly mountable in either of two mounting positions rotated 180 from each other about a rotational axis normal to the rear mounting side; wherein the first and second forward facing conveying surfaces are curved along at least a majority of the length of the ejector body.

15. The ejector of claim 14, wherein: the first and second forward facing conveying surfaces are curved along the entire length of the ejector body.

16. The ejector of claim 14, wherein axes of the mounting holes lie on a lengthwise center line of the ejector body.

17. The ejector of claim 14, wherein: each of the forward facing conveying surfaces has at least one depression defined therein, so that debris can pack into the depressions during use to create an abrasion resistant debris layer on the front conveying side.

18. An ejector for a road milling machine, comprising: an ejector body having a length and a width, the length being greater than the width, the body having a front conveying side and a rear mounting side, the front conveying side having first and second forward facing conveying surfaces adjacent lengthwise edges of the front conveying side, the first and second forward facing conveying surfaces being curved along at least part of the length of the ejector body; and first and second lengthwise spaced mounting holes defined through the ejector body between the front conveying side and the rear mounting side, the ejector body being reversibly mountable in either of two mounting positions rotated 180 from each other about a rotational axis normal to the rear mounting side; wherein the front conveying side has defined therein a recess between the first and second forward facing conveying surfaces; and wherein the first and second mounting holes communicate with the recess of the front conveying side.

19. The ejector of claim 18, wherein: at least a part of the recess is defined by a recess bottom located between two recess sides extending at widthwise oblique angles to the recess bottom.

20. The ejector of claim 14, wherein: the axes of the mounting holes lie on a lengthwise center line of the ejector body; the front conveying side has defined therein a recess between the first and second forward facing conveying surfaces, the recess having a recess length and a recess width, the recess length being parallel to the length of the ejector body and being longer than the recess width; the first and second mounting holes communicate with the recess of the front conveying side; and at least a part of the recess is defined by a recess bottom located between two recess sides extending at widthwise oblique angles to the recess bottom.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) The invention will be further explained below with reference to an exemplifying embodiment depicted in the drawings, in which:

(2) FIG. 1 is a front view of a milling drum of a road milling machine;

(3) FIG. 2 is a side view of the milling drum according to FIG. 1;

(4) FIG. 3 shows the view according to FIG. 2, enlarged and with a slightly modified depiction;

(5) FIG. 4 is a perspective front view of an ejector unit;

(6) FIG. 5 is a perspective rear view of the ejector unit according to FIG. 4;

(7) FIG. 6 is a perspective rear view of a carrier of the ejector unit according to FIG. 5;

(8) FIG. 7 is a front perspective view of the carrier according to FIG. 6;

(9) FIG. 8 is a perspective front view of an ejector of the ejector unit according to FIG. 4;

(10) FIG. 9 is a perspective rear view of the ejector according to FIG. 8;

(11) FIG. 10 is a perspective rear view of a second embodiment of an ejector unit having an ejector and a carrier; and

(12) FIG. 11 is a perspective front view of the arrangement according to FIG. 10.

DETAILED DESCRIPTION OF THE INVENTION

(13) 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.

(14) 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 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.

(15) FIGS. 4 and 5 show the ejector unit in isolation.

(16) 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.

(17) 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.

(18) 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 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.

(19) 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.

(20) 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.

(21) 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.

(22) 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.

(23) 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.

(24) 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.

(25) FIGS. 10 and 11 show a further variant embodiment of an ejector unit according to 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.

(26) 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 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.

(27) FIG. 3 is an end view of the milling tube 10 which can also be referred to as a milling drum 10. The milling drum 10 rotates in the feed direction indicated by the arrow V. The milling drum rotates about an axis indicated by the + in the center of the milling drum in FIG. 3. Directions generally parallel to the rotational axis may be referred to as axial directions and directions extending generally radially outward from the axis may be referred to as radial directions. Both the axial and radial directions can be considered to be generally transverse to the feed direction V.

(28) The ejector 20 seen in perspective in FIGS. 8 and 9, and in end view in FIG. 3, can be described as being generally rectangular in shape having a width which extends in a generally radial direction and a length extending in a generally axial direction. The conveying surface 21 of the ejector 20 may be described as generally forward facing or as facing in the working direction V.

(29) As best seen in FIG. 3, the carrier 30 may support the ejector 20 at an angle to a radius of the milling drum, which angle may be in a range of +/20 degrees, and more preferably a negative angle from about 5 degrees to about 20 degrees.