Impact bar

Abstract

An impact bar for installation in an axis-parallel impact bar mount of a rotor of an impact crusher includes front-side and backside holding regions between end faces, and longitudinal ribs projecting beyond the end faces. Each holding region is bordered by two longitudinal ribs which have a trapezoidal cross section to define a base and a topside at a distance to the base, with the base being wider than the topside. The longitudinal ribs have each an inner inclined flank and an outer flank, with the inner and outer flanks extending between the base and the topside and with the inner flank extending at a flank angle of 20 to 27 in relation to the x direction and configured such that only the inner flank is supportable in the installation position for transmission of a force into the impact bar mount at the rotor.

Claims

1. An impact bar for installation in an axis-parallel impact bar mount of a rotor of an impact crusher, said impact bar defining within a Cartesian coordinate system a longitudinal axis which extends in z direction in parallel relation to the impact bar mount in an installation position, a vertical axis which extends in y direction and is directed towards a radial head face of the impact bar, and a transverse axis which extends in x direction and is directed towards a length side of the impact bar, said length side of the impact bar having end faces, said impact bar comprising: front-side and backside holding regions between the end faces; and longitudinal ribs projecting beyond the end faces, each of the front-side and backside holding regions being bordered by two of the longitudinal ribs, said longitudinal ribs being arranged as mirror images in relation to an y-z plane and an x-z plane and having a trapezoidal cross section to define a base and a topside at a distance to the base, with the base having a width which is greater than a width of the topside, said longitudinal ribs having each an inner inclined flank and an outer flank, with the inner and outer flanks extending between the base and the topside and with the inner flank extending at a flank angle of 20 to 27 in relation to the x direction and configured such that only the inner flank is supportable in the installation position for transmission of a force into the impact bar mount at the rotor.

2. The impact bar of claim 1, wherein the impact bar has a width, measured in the x direction, with the width being sized as great in a region between the two longitudinal ribs as a width in a region of the end faces.

3. The impact bar of claim 1, wherein the inner flanks of the longitudinal ribs are arranged diagonally oppositely in pairs and extend in a common plane.

4. The impact bar of claim 1, wherein the outer flank forms in the installation position a shoulder for protection of an adjacent component of the rotor.

5. The impact bar of claim 1, wherein a cross sectional area of the impact bar has in an x-y plane a wearing part and a non-wearing part, with the wearing part representing at least 50% of the cross sectional area.

6. The impact bar of claim 5, wherein the wearing part has a width, with a ratio between the width of the wearing part of the impact bar and a minimum distance between the inner flanks of the longitudinal ribs being 1.8-2.2 to 1.

7. The impact bar of claim 1, wherein the inner flanks of the two longitudinal ribs are spaced from one another by a minimum distance, with a ratio of the minimum distance between the inner flanks to a height of the longitudinal ribs being 1.8-2.2 to 1.

8. The impact bar of claim 1, wherein a cross sectional area of the impact bar has in an x-y plane a wearing part and a non-wearing part, with the wearing part representing 55% of the cross sectional area.

9. A rotor, comprising: at least two impact bar mounts; and at least two impact bars received in the at least two impact bar mounts in one-to-one correspondence, each of the impact bars defining within a Cartesian coordinate system a longitudinal axis which extends in z direction in parallel relation to the impact bar mount in an installation position, a vertical axis which extends in y direction and is directed towards a radial head face of the impact bar, and a transverse axis which extends in x direction and is directed towards a length side of the impact bar, said length side of the impact bar having end faces, said impact bar comprising front-side and backside holding regions between the end faces, and longitudinal ribs projecting beyond the end faces, each of the front-side and backside holding regions being bordered by two of the longitudinal ribs, said longitudinal ribs being arranged as mirror images in relation to an y-z plane and an x-z plane and having a trapezoidal cross section to define a base and a topside at a distance to the base, with the base having a width which is greater than a width of the topside, said longitudinal ribs having each an inner inclined flank and an outer flank, with the inner and outer flanks extending between the base and the topside and with the inner flank extending at a flank angle of 20 to 27 in relation to the x direction and configured such that only the inner flank is supportable in the installation position for transmission of a force into the impact bar mount at the rotor, wherein each impact bar mount includes confronting impact bar clamps with projections for engagement between the longitudinal ribs, said projections having a same flank angle as a flank angle of the inner flanks of the longitudinal ribs.

10. The rotor of claim 9, wherein the impact bar has a width, measured in the x direction, with the width being sized as great in a region between the two longitudinal ribs as a width in a region of the end faces.

11. The rotor of claim 9, wherein the inner flanks of the longitudinal ribs are arranged diagonally oppositely in pairs and extend in a common plane.

12. The rotor of claim 9, wherein the outer flank forms in the installation position a shoulder for protection of an adjacent component of the rotor.

13. The rotor of claim 9, wherein a cross sectional area of the impact bar has in an x-y plane a wearing part and a non-wearing part, with the wearing part representing at least 50% of the cross sectional area.

14. The rotor of claim 13, wherein the wearing part has a width, with a ratio between the width of the wearing part of the impact bar and a minimum distance between the inner flanks of the longitudinal ribs being 1.8-2.2 to 1.

15. The rotor of claim 9, wherein the inner flanks of the two longitudinal ribs are spaced from one another by a minimum distance, with a ratio of the minimum distance between the inner flanks to a height of the longitudinal ribs being 1.8-2.2 to 1.

16. The rotor of claim 9, wherein a radially innermost contact zone between the impact bar and the impact bar clamps is located at the inner flanks of radially inner ones of the longitudinal ribs.

17. The rotor of claim 9, wherein a radially outermost contact zone between the impact bar and the impact bar clamps is located at the inner flanks of radially outer ones of the longitudinal ribs.

18. The rotor of claim 9, wherein the impact bar mount has an inner first region which widens in the x direction for receiving one of the end faces of the impact bar, and a second region which is narrower in the x direction than the first region and located between the projections, with a rounded transition zone being arranged between the first and second regions and extending at least 50% of a height of the topside of inner ones of the longitudinal ribs.

19. The rotor of claim 9, further comprising protective rotor plates arranged on the rotor and configured to cover the impact bar mounts in one-to-one correspondence, each said protective rotor plate having a border side which is arranged directly opposite to the topside of the longitudinal ribs.

20. The rotor of claim 9, wherein the impact bars have different heights.

21. The rotor of claim 9, wherein a cross sectional area of the impact bar has in an x-y plane a wearing part and a non-wearing part, with the wearing part representing 55% of the cross sectional area.

22. An impact crusher, comprising a rotor, said rotor comprising at least two impact bar mounts, and at least two impact bars received in the at least two impact bar mounts in one-to-one correspondence, each of the impact bars defining within a Cartesian coordinate system a longitudinal axis which extends in z direction in parallel relation to the impact bar mount in an installation position, a vertical axis which extends in y direction and is directed towards a radial head face of the impact bar, and a transverse axis which extends in x direction and is directed towards a length side of the impact bar, said length side of the impact bar having end faces, said impact bar comprising front-side and backside holding regions between the end faces, and longitudinal ribs projecting beyond the end faces, each of the front-side and backside holding regions being bordered by two of the longitudinal ribs, said longitudinal ribs being arranged as mirror images in relation to an y-z plane and an x-z plane and having a trapezoidal cross section to define a base and a topside at a distance to the base, with the base having a width which is greater than a width of the topside, said longitudinal ribs having each an inner inclined flank and an outer flank, with the inner and outer flanks extending between the base and the topside and with the inner flank extending at a flank angle of 20 to 27 in relation to the x direction and configured such that only the inner flank is supportable in the installation position for transmission of a force into the impact bar mount at the rotor, wherein each impact bar mount includes confronting impact bar damps with projections for engagement between the longitudinal ribs, said projections having a same flank angle as a flank angle of the inner flanks of the longitudinal ribs, wherein the impact crusher is reversible.

Description

BRIEF DESCRIPTION OF THE DRAWING

(1) Exemplary embodiments of the invention will be described hereinafter in greater detail with reference to purely schematic drawings.

(2) It is shown in:

(3) FIG. 1 a plan view of a rotor of an impact crusher;

(4) FIG. 2 a section through the rotor of FIG. 1 along the line II of FIG. 1;

(5) FIG. 3 a detail III of FIG. 2; and

(6) FIG. 4 a cross section of an impact bar.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

(7) FIG. 1 shows a rotor 1 of an otherwise not shown impact crusher. The rotor 1 includes a horizontal rotor shaft 2 which is mounted in bearings 3, 4. The rotor shaft 2 extends horizontally between the bearings 3, 4 and is driven by a pulley 5. Impact bars 6 are dispersed about the circumference of the rotor 1. The uppermost impact bar 6 in the drawing plane of FIG. 1 extends like all other impact bars 6 in parallel relation to the rotation axis D of the rotor shaft 2.

(8) The following description of the impact bars 6 relates to a Cartesian coordinate system. The origin of the coordinate system is situated in the middle of the impact bar 6, i.e. at half length (z axis), height (y axis) and width (x axis) of this impact bar 6. Referring to the impact bar 6 which is uppermost in the drawing plane and perpendicular to the rotation axis D, the x direction extends tangentially to the rotor 1. The y axis is the radial direction and points away from the rotor shaft 2. The z axis extends parallel to the rotation axis D.

(9) As is apparent from the sectional view of FIG. 2, a total of four impact bars 6 are evenly dispersed about the circumference of the rotor 1. The four impact bars 6 are identical, as are the associated impact bar mounts 7 within the rotor 1. The impact bar mounts 7 represent pockets that extend in length direction of the rotor, i.e. parallel to the rotation axis D of the rotor shaft 2. With reference to the coordinate system introduced in FIG. 1, the pockets extend in z direction.

(10) The impact bars 6 are configured in cross section substantially rectangular. With reference to the y-z plane and also with reference to the x-z plane, the impact bars are mirror images. They have each radial head faces which extend in substantial parallel relation to the x-z plane. As the impact bars 6 involve cast parts, the head faces 8 may have a slight draft as caused by casting. The length sides 9, 10 of the impact bar 6 extend at a parallel distance to one another and as a result extend substantially perpendicular to the head faces 8.

(11) Two terminal end faces 11, 12, 13, 14 are situated at the length sides 9, 10 and provide impact surfaces. Provided between the end faces 11-14 of each length side 9, 10 are undercuts, respectively, which are designated as holding regions 15, 16. The holding regions 15, 16 are respectively limited by two longitudinal ribs 17, 18, 19, 20 as is apparent also by the illustration of FIGS. 2 to 4. All longitudinal ribs 17-20 are of identical configuration and have the same cross section. The longitudinal ribs 17-20 have a trapezoidal cross section and a have a wider base 21 and a narrower topside 22 (FIG. 4). Inclined flanks extend between the base 21 and the topside 22. Inner flanks 23-26 confront one another and limit the holding regions 15, 16. Outer flanks 27 form the transition to the end faces 11-14. All edges are rounded.

(12) Arrow P1 in FIG. 2 symbolizes the rotation direction of the rotor shaft 2 and thus of the rotor 1. Due to the rotation direction, the end face 11 represents the impact surface that is subject to stress. At this rotation direction, also the designations front side and backside of the impact bar 6 could be used. As the rotation direction is reversible, the opposite end face 14 may likewise serve as impact surface, when operation is reversed.

(13) A rotary movement is transmitted via the rotor 1 and the impact bar mounts 17 onto the impact bars 6. The impact bars 6 are pushed into the impact bar mounts 7 in a manner not shown in greater detail in z direction, i.e. in length direction of the rotor 1. The impact bars are secured in the installation position against axial displacement. As a result of the formfitting engagement of impact bar clamps 28, 29 between the longitudinal ribs 17-20, the impact bars 6 are held captive in the rotor 1. The impact bar clamps 28, 29 rest upon the inner flanks 23-26 of the impact bar 6, respectively. Due to the inclined inner flanks 23-26, the undercut region, i.e. the respective holding region 15, 16, has a trapezoidal cross section with rounded corners.

(14) As becomes apparent from the enlarged illustration of FIG. 3, a contact zone is established between the flanks 23-26 and the impact bar clamps 28, 29. The impact bar clamps 28, 29 have for that purpose opposing identical projections 30, 31 with a geometry and in particular with support faces which conform to the flank angles of the inner flanks 23-26. The flank angle W1 is depicted in FIG. 4.

(15) FIG. 3 shows that the radially outermost contact zone between the impact bar clamps 28, 29 and the impact bar 6 is formed by the radially inner flanks 23, 24 of the radially outer longitudinal ribs 17, 19. Likewise, the radially innermost contact zones are located between the inner flanks 25, 26 and the respective projections 30, 31 of the impact bar clamps 28, 29. There are no further contact zones radially above or below the mentioned regions. Thus, the radial outer longitudinal ribs 17, 19 project beyond the impact bar clamps 28, 29 and radially rest virtually from outside against the rotor 1. They are protected by protective rotor plates 32 which are screwed onto the rotor 1 radially from outside. The protective rotor plates 32 cover the impact bar clamps 28, 29 and protect them against wear. The protective rotor plates 32 have each a border side 33 which confronts the topsides 22 of the longitudinal ribs 17, 19. In this way, the longitudinal ribs 17, 19 are protected in this region against wear. The protective rotor plates 32 are detachably secured.

(16) FIG. 3 shows an enlarged view of the area III according to FIG. 2. Various wear lines are plotted in the radially outer part of the impact bar 6. The wear lines show that the rotor 1 has been operated at the beginning counterclockwise, since the left upper corner of the impact bar 6 has been stripped off at first. Subsequently, the rotation direction has been reversed, so that the end face 11 on the right-hand side of the drawing plane serves as impact surface. Thus, the right upper corner of the impact bar 6 has been stripped. After multiple reversals of the rotor 1, the wear limit V has been reached. The wear limit V is located approximately in prolongation of the radially outer flanks 27. The wear limit V is the limit for maximum use of the impact bar 6. The impact bar 6 has in this state an approximately triangular remaining cross section at the wear limit V.

(17) When the wear limit V has ultimately been reached, the impact bar 6 is pulled out of the impact bar mount 7 in length direction of the rotor 1 and can be turned about its length axis, so that the previously inner end faces 13, 14 now face outwards. There is no preferential direction of the impact bar 6, when turning by 180 degrees. It is irrelevant, whether the impact bar 6 is turned about its length axis only, or turned at the same time during turning about its vertical axis. The rotational symmetry of the impact bar 6 enables both insertion directions into the impact bar mount 7.

(18) FIG. 3 shows that the impact bar mount 7 is configured relatively wide in the region of the impact bar 6 that is not in engagement. In the impact bar mount 7, there is an inner region 34 which is widened in x direction. The width of this inner region 34 is greater than the width of the impact bar 6, measured across the longitudinal ribs 18, 20. A region 35 that is narrower in x direction is situated between the projections 30, 31. The wider region 34 is connected to the narrower region 35 by a transition zone 36. The transition zone 36 is rounded. Rounding of the transition zone 36 extends across at least 50% of the height of the topside 22 of the inner longitudinal ribs. The provision of the great rounding radius prevents stress in this region of the impact bar clamps 28, 29. This is important because this region of the impact bar clamps 28, 29 needs to absorb not only the centrifugal forces that are exerted from the impact bar 6 onto the rotor 1 but also because the torque of the rotor 1 has to be transmitted from the impact bars 6 onto the material being comminuted. The impact bar according to the invention includes for this purpose special proportions which will be described hereinafter with reference to FIG. 4.

(19) The impact bar 6 includes in this exemplary embodiment a height H1 of 320 mm at a width B1 in its impact zone of 80 mm. The ratio of height to width is 4:1.

(20) The impact bar 6 is slightly wider in its mid mounting portion that is not subject to wear than in the impact zone. The longitudinal ribs 17-20 have each a height of 20 mm, measured from the terminal end faces 11-14 (width B2). Their topsides 22 have a height H2 of 20 mm. The height H3 is measured at the base 21 and indicates the minimum distance of the inner flanks 23-26 of the longitudinal ribs 17-20.

(21) FIG. 4 further shows that the flank angles W1 are identical for all plotted flanks of the longitudinal ribs 17-20. They amount to 25 degree. The inner flanks 23-26 extend each radially from a center point M of the impact bar 6. Thus, the illustrated dash-dot lines intersect as prolongation of the respective inner flanks 23-26 in the center point M. The center point M lies on the length axis of the impact bar 6 (z axis), about which the mounted impact bar 6 can theoretically swing within the impact bar mount 7 during operation within the scope of the provided tolerances.

(22) When a clockwise rotation direction of the rotor 1 is involved, i.e. in direction of arrow P1 (FIG. 2), a force originating from rotor 1 is applied onto the inner flanks 24, 26. At the same time, both radial inner flanks 25, 26 of the lower longitudinal ribs 18, 20 maintain the impact bar 6 in position. The centrifugal forces of the impact bar 6 are absorbed there. When impacting material exerts a force onto the end face 11, predominantly the upper longitudinal rib 19 on the left-hand side of the drawing plane and in addition the longitudinal rib 18 on the lower right-hand side are exposed to stress, because a torque in direction of arrow P2 about the center point M is applied upon the impact bar 6. The resultant forces are taken up via these inner flanks 25, 26 and introduced into the impact bar clamps 28, 29. This involves normal forces, i.e. forces which extend perpendicular upon the flanks.

(23) FIG. 4 further shows that the width B3 of the impact bar 6, which is measured across the topsides 22 of the longitudinal ribs 18, 20, is sized 1.5 times the width B1 of the impact bar 6 in the region of its impact zone. In the holding region 15, 16 in the middle of the impact bar 6, the width B4 is sized at least as the width B1 in the region of the end faces 11, 12, thereby preventing the presence of any notch as material weakening. In this exemplary embodiment, the width B4 in the region between the longitudinal ribs 17-20 is 85 mm as compared to 80 mm in the impact zones.