GB1558925A - Beater bar for impact crusher rotors - Google Patents

Description

(54) BEATER BAR FOR IMPACT CRUSHER ROTORS (71) We, HAZEMAG DR. E. ANDREAS GmbH & Co., a German Company, of Rosnerstrasse 6-8, D-44 Minster, German Federal Republic do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is performed, to be particularly described in and by the following statement:: The invention relates to a beater bar for impact crusher rotors having, with a view to reversibility, a mirror-symmetrical elongate profile of approximately constant breadth perpendicular to the or each beating surface, which bar on the rearward side, in the direction of rotation of the rotor, has at least one surface which abuts rearwards and radially from the inside against a support member mounted securely on the rotor and, on the front side, at least one backing surface for a key which keeps the beater bar in engagement with the support member.

Such reversible but non-rotatable beater bars are known in various embodiments. They are particularly suitable for impact crusher rotors which comprise several discs fixed on a shaft, which are provided on the periphery with recesses in which the beater bars are inserted. Thus in the case of these rotors, the beater bars between the discs are exposed to wear additionally on the inner halves of their front sides. so that these surfaces cannot be used as backing surfaces on the rear side. In the event of reversal. i.e. upon swivelling about a central transverse axis, the rear side remains at the rear and the front side remains at the front, the difference being that the inner half is then at the outside and vice versa.

Such a beater bar is known for example from the German OS 2 148 752. Like many other known beater bars, it has an elongate profile of constant breadth perpendicular to the beating surface and a straight course. Since the outer part of the front surface of the beater bar serving as a beating surface should be inclined, preferably radially or only slightly forwards, so as to obtain a satisfactory comminuting action, in this design of the beater bar an essentially radial position of the entire beater bar in the recesses of the rotor discs is obtained. This has the result that these recesses have to be indented forwards, on account of the keys disposed in front of the beater bars in the direction of rotation of the rotor and the pressure devices for the keys.This amounts to a weakening of the rotor jaws which engage from the front round the beater bar and which, in any case, are weaker in view of the fact that they are set back radially in relation to the rear rotor jaws.

Since the backing surfaces for the keys also extend radially in the case of these beater bars, the abutting surface in the edge recesses has to extend obliquely inwards and forwards, which gives rise to undercuts which are difficult to machine. Moreover, in order to achieve a simple beater-bar configuration. the support members arranged securely on the rotor have to be provided with longitudinal ribs or grooves which are equally difficult to machine. Finally, in these known beater bars the backing surfaces for the keys are provided outside the plane of symmetry of the beater bar. which has the result that, after the reversal of the beater bar, the keys have to be applied against surfaces which previously have been subjected to at least some degree of wear and, therefore, are no longer accurately plane.

It is the object of the invention to devise a beater bar having a simple as possible a profile, which can be tightly locked in a rotor which need not have the aforementioned disadvantages, and which itself also has few and readily machinable surfaces, and, in addition is also rigid.

This is achieved surprisingly easily in accordance with the invention in that the profile of the beater bar is of rearwardly bent shape in relation to the direction of rotation of the rotor, the at least one backing surface for the key(s) being provided in the centre of the front side perpendicularly to the plane of symmetry of the beater bar. The kink in the profile of the beater bar gives rise to a beater bar which in foundry technology is no more complicated than a beater bar which is of continuous rectangular profile. However, on its rear side it has a surface such as is suitable for backing and for engaging behind the support member of the rotor.Furthermore, the kink in the profile improves the bending strength of the beater bar, which is particularly advantageous in the case of bars made of high-manganese steel, since the beater bar when struck from the side by comminution material tends to stretch on account of the initially soft nature of its material, whereby a bending moment occurs. On the front side it is readily possible to provide at least one backing surface for the key(s) which can be easily machined, even if it does not take the form of a casting reinforcement. These backing surfaces are completely covered by the keys in operation, so that they are not subject to any wear and, therefore, can serve undamaged to back the keys even in the case of a reversed beater bar.

As a result of the inclination of these backing surfaces in relation to the two outer surface portions of the front side, they are also inclined in relation to the radial direction in the case of a beater bar installed with a radial beating surface. This makes it possible to select the keys so that the surfaces of the rotor-disc recesses, against which the keys abut, extend parallel to the backing surfaces of the support members, against which the beater bar abuts with its rear side, so that both surfaces can be machined in a clamping position of the rotor.

Finally, the already mentioned inclined position of the backing surfaces for the keys results in a somewhat outwardly directed pressure direction which brings about very satisfactory clamping of the beater bar, in cooperation with the backing surfaces of the support members which are intended to be located further toward the exterior so as satisfactorily to take up the shocks occurring with impacts on the beater bar.

Particular satisfactory clamping of the beater bar is obtained if the two surfaces of the rear side of the beater bar, which surfaces extend at an obtuse angle to one another, each project to some extent beyond the plane of symmetry of the beater bar and are then directed rearwards at an angle, so that two longitudinal grooves are formed. It is then possible for the support members of the rotor to have an internal surface running approximately in a peripheral direction, against which the beater bar abuts radially from inside. The integrallycast longitudinal grooves can be machined relatively easily by grinding, as necessitated by inaccuracies arising in casting, especially as the surfaces to be ground are not large.In view of the fact that the longitudinal grooves are situated on rear side of the beater bar subjected to pressure, they are quite acceptable, especially as this side abuts fully with its backing surfaces.

The angle of the grooves is preferably 90".

The inner portions, i.e. the portions, adjacent to the plane of symmetry, of the surfaces of the rear side extending at an obtuse angle to one another, are preferably slightly raised and machined in relation to the outer portions.

In fact, United States Patent Specification No. 2 747 803 discloses a beater bar in which the rear surface exhibits a rearward kink in its basic course. However, the front side is straight in its basic course, so that the beater bar has a very wide outer surface which lead to high frictional wear. Its profile is also complicated thereby. In this case provision is made for the backing surface provided on the front side of the beater bar to be recessed, since it is not possible here to machine this type of surface without special stepped portions, as is possible in the present beater bar. In spite of this it is even necessary here to arrange a connecting piece between the beater bar and key, so that the key can move freely in relation to the beater bar.

The same is true of the beater bar according to the German Patent Specification No. 1143 380, in which the front surface is additionally bent forwards.

Beater bars are also known in which the front side and rear side are bent in the same direction, so that a kinked profile is produced, e.g. as in Figure 3 of German Patent Specification 930 839. These beater bars do not, however, have the simple profile as in the beater bar of the invention. They are also provided in the rotor exactly in reverse, i.e. bent forwards in the rotational direction of the rotor, so that the advantages obtained with the invention cannot be achieved.

An impact crusher rotor equipped with beater bars according to the invention also forms part of the subject-matter of the invention, in which these beater bars with an approximately radially directed outer part are so clamped that the inner part is angled rearwards in the rotational direction of the rotor. since in this case the recesses provided on the periphery, whose contours are diverted as closely as possible round the parts required for clamping the beater bars and round the beater bars themselves, can be formed very favourably in respect of the configuration of the jaws between which the beater bars are clamped. This is particularly important in the case of rotors which comprise a plurality of rotor discs mounted on a common axis.

With regard to the machining of the surfaces provided on the rotor, between which the beater bars are clamped, it is advantageous if the surfaces of the support members, against which the beater bar abuts rearwards, and the surfaces, against which the keys bear on the rotor, extend parallel to one another.

The drawing shows diagrammatically two examples of embodiment of the beater according to the invention installed in an impact crusher rotor.

The beater bar 1 is installed in a rotor which comprises a plurality of rotor discs 2 which are mounted on a shaft (not shown). These discs have on their periphery several recesses 3, e.g.

four, to whose trailing edges 4 (in relation to the rotational direction - arrow a) there is attached by welding a support member in the form of a continuous backing bar 5. The front surface of the backing bar, against which the beater bar abuts rearwardly, comprises an outer, approximately radially directed portion 6 and a portion 7 extending at an angle thereto and pointing markedly inwards to a greater or lesser extent.

At the leading edge 8 of the recess 3 there is provided a protective cap 9 which engages over the edge and is provided with a projecting edge 10 which engages in a corresponding groove 11 of the edge 8. The cap has on its rear side a guide groove 12 in which a key 13 can slide, which key can be pressed outwards by a hydraulic ram 14 provided at the bottom of the recess 3.

The beater bar 1 has mirror-symmetrical kinked profile. The plane of symmetry b of the beater bar passes through the axis shown in dash-dot line. The rear side of the beater bar has two outer surface portions 15, and two inner surface portions 16 adjoining the plane of symmetry which are slightly raised and machined in relation to the surface portions 15. The front side of the beater bar has two outer surface portions 17 serving as beating surfaces and a central surface portion 18 which extends perpendicularly to the plane of symmetry b, which serves as backing surface for the key 13 and is likewise machined. The surface portion 18 needs to be provided in each case only at those locations where a key is situated, i.e. in the zone of the rotor discs 2. Between the discs the outer surface portions can converge up to the plane of symmetry, as indicated by dashed lines.The keys 13 can thus additionally serve to prevent longitudinal displacement of the beater bar.

In the case of the beater bar illustrated in Figure 2, the inner surface portions 16 are extended beyond the plane of symmetry b. In this way there are formed two grooves 19 which are bounded externally by surfaces 2(), with which the beater bar abuts radially from inside against the correspondingly extending portion 7 of the backing surface 6, 7 of the backing bar 5. This design of the beater bar results in a simpler conformation of the backing bar and better retention of the beater bar in the rotor. Since the grooves are located on that side of the beater bar subjected to pressure, they do not delecteriously affect the durability of the beater bar.

The outer surface portions 17 can. however. in contrast to the illustration of the drawing, also extend over the entire width of the beater bar only as far as the central surface portions 18, in which case for better machinability of the backing surfaces it is possible for the surface portions 18 to be made slightly raised within the width of the wedges.

WHAT WE CLAIM IS: 1. A beater bar for an impact crusher rotor having. with a view to reversibility, a mirror-symmetrical elongate profile of approximately constant breadth perpendicular to the or each beating surface. which bar on the rearward side, in the direction of rotation of the rotor. has at least one surface which is adapted to abut rearwards and radially from the inside against a support member mounted securely on the rotor and, on the front side, at least one backing surface for a key which keeps the beater bar in engagement with the support member, wherein the profile is kinked rearwardly in shape, and the backing surface for the key is provided in the centre of the front side of the beater bar perpendicular to the plane of symmetry.

2. A beater bar as claimed in claim 1, wherein two abutting surfaces are provided on the rearward side. which extend towards one another at an obtuse angle and are each projected to some extent beyond the plane of symmetry and are then directed rearwardly at an angle, so that two longitudinal grooves are formed in the beater bar.

3. A beater bar as claimed in claim 2, wherein the second angle is 90 .

4. A beater bar as claimed in claim 2 or claim 3, wherein the inner portions of the two abutting surfaces of the rear side are slightly raised and machined in relation to the outer portions of the abutting surfaces.

5. A beater bar for an impact crusher rotor substantially as hereinbefore described with reference to and as illustrated in the accompanying drawing.

6. A rotor for an impact crusher including at least one beater bar as claimed in any one of the preceding claims.

7. A rotor as claimed in claim 6 wherein the portion of the support member against which the beater bar abut rearwardly, and the surface of the rotor disc, against which the key bears, extend parallel to one another.

8. An impact crusher including a rotor as claimed in claim 6 or claim 7.

**WARNING** end of DESC field may overlap start of CLMS **.

Claims (8)

**WARNING** start of CLMS field may overlap end of DESC **. rotor, extend parallel to one another. The drawing shows diagrammatically two examples of embodiment of the beater according to the invention installed in an impact crusher rotor. The beater bar 1 is installed in a rotor which comprises a plurality of rotor discs 2 which are mounted on a shaft (not shown). These discs have on their periphery several recesses 3, e.g. four, to whose trailing edges 4 (in relation to the rotational direction - arrow a) there is attached by welding a support member in the form of a continuous backing bar 5. The front surface of the backing bar, against which the beater bar abuts rearwardly, comprises an outer, approximately radially directed portion 6 and a portion 7 extending at an angle thereto and pointing markedly inwards to a greater or lesser extent. At the leading edge 8 of the recess 3 there is provided a protective cap 9 which engages over the edge and is provided with a projecting edge 10 which engages in a corresponding groove 11 of the edge 8. The cap has on its rear side a guide groove 12 in which a key 13 can slide, which key can be pressed outwards by a hydraulic ram 14 provided at the bottom of the recess 3. The beater bar 1 has mirror-symmetrical kinked profile. The plane of symmetry b of the beater bar passes through the axis shown in dash-dot line. The rear side of the beater bar has two outer surface portions 15, and two inner surface portions 16 adjoining the plane of symmetry which are slightly raised and machined in relation to the surface portions 15. The front side of the beater bar has two outer surface portions 17 serving as beating surfaces and a central surface portion 18 which extends perpendicularly to the plane of symmetry b, which serves as backing surface for the key 13 and is likewise machined. The surface portion 18 needs to be provided in each case only at those locations where a key is situated, i.e. in the zone of the rotor discs 2. Between the discs the outer surface portions can converge up to the plane of symmetry, as indicated by dashed lines.The keys 13 can thus additionally serve to prevent longitudinal displacement of the beater bar. In the case of the beater bar illustrated in Figure 2, the inner surface portions 16 are extended beyond the plane of symmetry b. In this way there are formed two grooves 19 which are bounded externally by surfaces 2(), with which the beater bar abuts radially from inside against the correspondingly extending portion 7 of the backing surface 6, 7 of the backing bar 5. This design of the beater bar results in a simpler conformation of the backing bar and better retention of the beater bar in the rotor. Since the grooves are located on that side of the beater bar subjected to pressure, they do not delecteriously affect the durability of the beater bar. The outer surface portions 17 can. however. in contrast to the illustration of the drawing, also extend over the entire width of the beater bar only as far as the central surface portions 18, in which case for better machinability of the backing surfaces it is possible for the surface portions 18 to be made slightly raised within the width of the wedges. WHAT WE CLAIM IS:

1. A beater bar for an impact crusher rotor having. with a view to reversibility, a mirror-symmetrical elongate profile of approximately constant breadth perpendicular to the or each beating surface. which bar on the rearward side, in the direction of rotation of the rotor. has at least one surface which is adapted to abut rearwards and radially from the inside against a support member mounted securely on the rotor and, on the front side, at least one backing surface for a key which keeps the beater bar in engagement with the support member, wherein the profile is kinked rearwardly in shape, and the backing surface for the key is provided in the centre of the front side of the beater bar perpendicular to the plane of symmetry.

2. A beater bar as claimed in claim 1, wherein two abutting surfaces are provided on the rearward side. which extend towards one another at an obtuse angle and are each projected to some extent beyond the plane of symmetry and are then directed rearwardly at an angle, so that two longitudinal grooves are formed in the beater bar.

3. A beater bar as claimed in claim 2, wherein the second angle is 90 .

4. A beater bar as claimed in claim 2 or claim 3, wherein the inner portions of the two abutting surfaces of the rear side are slightly raised and machined in relation to the outer portions of the abutting surfaces.

5. A beater bar for an impact crusher rotor substantially as hereinbefore described with reference to and as illustrated in the accompanying drawing.

6. A rotor for an impact crusher including at least one beater bar as claimed in any one of the preceding claims.

7. A rotor as claimed in claim 6 wherein the portion of the support member against which the beater bar abut rearwardly, and the surface of the rotor disc, against which the key bears, extend parallel to one another.

8. An impact crusher including a rotor as claimed in claim 6 or claim 7.