GB2183504A - Crushing apparatus - Google Patents

Abstract

A crushing apparatus is fitted with hammers which preserve the hammer spindle. The bores of these hammers have a wall which is made curved away from the hammer spindle towards the two edges, leaving a shorter, straight middle piece. Thus the individual hammer can execute a limited rolling movement on the hammer spindle, without unfavourably influencing the hammer spindle in doing so. Likewise the edges of the hammer are also expediently rounded so that the stressing of the rotor discs by the hammer is minimised. As well as the usual hammers, usual striker rings can also be formed so that the hammer spindle cannot be deformed or destroyed by them. <IMAGE>

Description

SPECIFICATION Crushing Apparatus The invention relates to a crushing apparatus, especially a hammer crusher for crushing scrap having a fast-rotating cylindrical rotor provided with hammers arranged articulatedly between the rotor discs, where the hammers possess appropriately large bores for the passage of the hammer spindles mounted in the rotor discs.

Such crushing apparatuses are used especially for the crushing of hard mass goods in coarse pieces or for example for the crushing of scrap, in that the hammers arranged movably, that is pivotably, on the fast-rotating rotor shutter the material for crushing. By reason of the articulated arrangement of the individual hammers, sufficient play must also remain for them between the rotor discs, which has a disadvantageous effect as regards wear. Increased wear here occurs as well due to the fact that the hammer spindle and also the adjacent rotor discs are additionally stressed by an oblique loading of the hammer. The hammer, which is fitted on to the hammer spindle, here presses upon the hammer spindle with the corner of the bore opposite to the loading, and leads to stresses here, especially deformations.Likewise the rotor disc is heavily stressed by the in part sharp edges of the lower part of the hammer when the hammer is correspondingly placed or loaded obliquely.

Attempts have been made to reduce the wear by slight bluntings of the edges of the bore. In that case it appeared that thus only a shift of the stressing occurs, without appreciable reduction of the total wear. The stressing of the hammer spindle by the edges of the bore in the hammer has an especially disadvantageous effect because thus grooves and beads are produced which in the one case attenuate the hammer spindle and in the other make passage through the rotor discs and pushing on of the hammers more difficult. In the case of heavy stresses of the hammer spindle finally fracture of this spindle can occur.

The invention is based upon the problem of minimising the wear of the hammers and accessories, especially the hammer spindles.

In accordance with the invention the problem is solved in that the walls of the bores of the hammers are made curved away from the hammer spindle towards both edges, leaving a shorter, straight middle piece.

Contrary to the expectation of persons acquainted with the art, with hammers of such formation a substantially lower wear occurs, especially a distinct relieving of the hammer spindles. Due to the corresponding formation of the curves and due to their deliberate formation the hammer is prevented from tilting away without any oblique loading and then leading to unnecessary wear. On the other hand when oblique loading does occur the hammer can safely yield so far that it leaves the hammer spindle practically unloaded. Channels and beads no longer occur on the hammer spindles, leading to longer lives and substantially simplified fitting. It is also surprising that the crushing effect is not thereby impaired, but rather even improved.This is presumably attributabie to the fact that the hammers, which now are also laterally limitedly movable, act optimally upon the material for crushing.

In addition to the rounding of the walls of the bores it is also possible to make the wall bevelled towards the edges away from the hammer spindle.

In this case the transitions should again each be rounded off to such extent that shear stressing of the hammer spindle does not occur.

Unintended oblique placing of the hammer without loading is prevented, for one part, and an expedient yielding under oblique loading is achieved for the other part if, as provided according to the invention, the middle piece has a length of 113 or less of the entire bore. Such a formation can also be produced without great expense in manufacturing technique, especially in the case of cast hammers where the finishing work then necessitates only slight expense.

According to the utilisation of the crushing apparatus, especially according to what material is to be crushed, it is advantageous if the hammer is formed as a striker ring with extension pieces arranged in distribution and a stepped bore. Here again the stepped bore is formed so that a straight middle piece remains centrally.

In order that the rotor discs too may be stressed as little as possible by the hammers placing themselves obliquely, it is provided in accordance with the invention that the edges of the lower part of the hammer are also rounded off. If these edges are adapted, as regards their rounding, to the roundings of the bores, success is achieved in largely reducing the wear. The roundings permit rolling for the one part on the hammer spindle and for the other on the rotor discs.

Another possibility of blunting the edges of the lower part is that where the edges of the lower part of the hammer comprise rounded-off extension pieces. These extension pieces likewise render possible limited rolling of the hammer edges on the rotor discs with substantial reduction of the stressing of the rotor discs. The extension pieces should here expediently be shaped leaving a channel between them and forming additional support faces for the hammer. The extension pieces can here approximately double the length and width of the lower part, without the weight of the entire hammer thereby being unfavourably varied. The channel and the corresponding formation of the extension pieces contribute to this. Since the extension pieces are rounded off, thus again the wear is minimised.

A uniform rolling movement of the hammer on the hammer spindle and on the rotor discs is ensured, as already mentioned further above, if the roundings of the edges, extension pieces and bore are formed in conformity with one another. The striking edges of the hammer should here also be rounded in order thus to counteract any occurring stresses when the hammers enter and turn through the gap formed between the adjacent rotor discs.

The invention is especially distinguished in that the lives of the crushing parts of hammer crushers and the like crushing apparatuses can be substantially lengthened in that the wear as a whole is concentrated upon the hammers, while it is substantially kept away from the retaining parts such as the hammer spindles and also the rotor discs. The extra production expense is slight, especially it It is a matter of castings, since the roundings and slopes can here be produced relatively simply. On the other hand the hammer spindles, which come high in the production expense, remain unaltered, which has a further advantageous effect.

Further details and advantages of the object of the invention appear from the following description of the accompanying drawing, in which a preferred example of embodiment is represented with the details and individual parts necessary for this purpose, and wherein:- Figure 1 shows a diagrammatic lateral elevation of a hammer crusher, Figure 2 shows a hammer in longitudinal section, Figure 3 shows a hammer in lateral elevation, Figure 4 shows two hammers of different formations between rotor discs, in section, Figure 5 shows a striker ring in section and Figure 6 shows a striker ring in lateral elevation.

The crushing apparatus as represented in Figure 1 is a hammer crusher 1 with a cylindrical rotor 2 on which several hammers 3 are movably provided, arranged at intervals. These hammers can rotate about the hammer spindles 4 so that in the case of excessive resistance they can yield to this resistance and turn away between the rotor discs 5, which are here merely indicated. The material for crushing, introduced into the hammer crusher 1, is discharged continuously through the floor after conclusion of the crushing operation.

Figure 2 shows one of the hammers 3 in section.

This hammer 3 comprises in the lower half a bore 6, the wall of which extends straight and parallel to the upper and under sides of the hammer not throughout but rather only in the region of the relatively narrow middle piece 8. Thence the wall 7 then extends arcuately or even obliquely towards the edges 9 and 10. The arcuate course as indicated in Figures 2 and 3 has the advantage that the hammer 3 can practically roll laterallv on the hammer spindle 4.

The wall 7 is formed with arcuate course in the region of both the upper part 12 and the under part 13, and also has rounded-off edges 14 in the region of the under part 13. Likewise the striking edges 15 in the region of the upper part 12 are rounded, so that extensive preservation of the rotor disc5 is guaranteed.

Figure 3 shows the hammer 3 in lateral elevation, the special formation of the bore achieved by the obliquity or rounding being made clear in the region of the bore 6. The rounded-off edge 14 is also visible in the region of the under part 13.

Figure 4 shows two inserted hammers 3, 3', where the hammer 3 corresponds to that shown in Figure 2, while the hammer 3' comprises extension pieces 16, 17 formed on to the under part 13. Due to this lengthening of the under part 13 an additional support face 18, 19 is produced which additionally limits the oblique placing of the hammer 3', admittedly without thereby additionally stressing the rotor disc 5. This is prevented by the fact that the extension pieces 16, 17 are rounded. Centrally between them a channel has remained so as not unnecessarily greatly to alter the weight ratio of the hammer 3'.

Figures 5 and 6 show a striker ring 20 which corresponds in function to the hammer 3 or 3', for which purpose the striker ring comprises several extensions 21. Here again the bore 22 is of stepped formation exactly as in the hammer 3, so that the striker ring 20 can carry out a certain rolling movement on the hammer spindle 4.

Claims (10)

1. Crushing apparatus, especially hammer crusher for crushing scrap with a fast-rotating cylindrical rotor provided with hammers arranged articulated between the rotor discs, the hammers comprising correspondingly large bores for the passage of the hammer spindles mounted in the rotor discs, characterised in that the walls (7) of the bores (6) of the hammers (3) are made curved away from the hammer spindle (4) towards the two edges (9, 10), leaving a shorter, straight middle piece (8).

2. Crushing apparatus according to Claim 1, characterised in that the wall (7) is bevelled away from the hammer spindle (4) to the edges (9, 10).

3. Crushing apparatus according to Claim 1, characterised in that the middle piece (8) has a length of 1/3 or less of the entire bore (6).

4. Crushing apparatus according to Claim 1, characterised in that the hammer (3) is made as a striker ring (20) with extension pieces (21) arranged in distribution and a stepped bore (22).

5. Crushing apparatus according to Claim 1, characterised in that the edges (14) ofthe under part (13) of the hammer (3) are also rounded.

6. Crushing apparatus according to Claim 1, characteriseo In that the edges (14) of the under part (13) of the hammer (3) comprise rounded-off extension pieces (16, 17).

7. Crushing apparatus according to Claim 6, characterised in that the extension pieces (16, 17) are shaped leaving a channel between them and forming additional support faces (18, 19) for the hammer (3).

8. Crushing apparatus according to Claim 1 and Claim 5 or Claim 6, characterised in that the roundings of the edges (14), extension pieces (16, 17) and of the bore (6) are formed in correspondence with one another.

9. Crushing apparatus according to Claim 1, characterised in that the striking edges (15) of the hammer (3) are also rounded.

10. A crushing apparatus as claimed in claim 1, substantially as described herein with reference to and as illustrated by the example shown in the accompanying drawings.