EP0110665B1

EP0110665B1 - Comminuting apparatus

Info

Publication number: EP0110665B1
Application number: EP19830307148
Authority: EP
Inventors: Stuart Geoffrey Gibbins Bloor
Original assignee: PEAK PATTERN CO Ltd
Current assignee: PEAK PATTERN CO Ltd
Priority date: 1982-11-27
Filing date: 1983-11-23
Publication date: 1987-06-10
Also published as: DE3371966D1; EP0110665A3; EP0110665A2

Description

This invention relates to roller crushers, which are machines for crushing materials, typically minerals, usually to reduce them to particles of a particular maximum size. Roller crushers comprise at least one, and usually two contra-rotating, roll assembly(ies), each provided with crushing members, e.g. teeth, on their periphery.
It is obviously important that the crushing members on each roll assembly are effectively prevented from movement relative to the roll assembly, as this would seriously detract from the crushing action. Thus, it is known to provide a solid shaft or a drum with spaced annular discs formed with teeth at their peripheries, and to weld or bolt the discs to the drum or shaft. It is also known to provide a square sectioned shaft with a series of discs having a central hole to fit the shaft, the centre hole extending to lobes, and with concrete run down the aligned lobes to key the discs to the shaft. With such constructions, any wear or damage to, particularly, the teeth on the discs, occasions considerable time being spent in the removal of the existing discs from the shaft or drum and hence the apparatus being out of commission for considerable periods of time. Equally, such apparatus cannot readily be modified to suit different crushing requirements, again because of the problem of removing one set of discs and their replacement by discs of a different tooth profile or disc diameter.
German Auslegeschrift 1 221 081 discloses a roll for a roller crusher which comprises a plurality of tooth bearing segments which are detachably mounted on a roll body. In this specification, each tooth bearing segment is secured to the roll body by means of a plurality of screws. Thus, in orderto change one or more of the tooth bearing segments, considerable time and effort is required, to access, release and subsequently retighten the fixing screws.
U.S. Patent Specification 4 219 291 discloses a plurality of circular elements which are assembled side-by-side on a drum. However, this specification does not disclose a roll which is suitable for use in a roller crusher. Rather, it discloses a rotary cutter, in which the circular elements co-operate with a bed knife assembly, to cut strands of filaments into pellets. More importantly, however, the circular cutting discs can be removed from the drum only by removing the drum assembly from its bearings, and then disassembling the apparatus, so that the cutting disc can be removed in turn from the drum, in a direction only axially thereof.
The present invention aims to provide roll assemblies for roller crushers, which may be improved in terms of ease of replacement of tooth bearing elements.
According to a first aspect of the invention, there is provided a roll assembly for a roller crusher, the assembly comprising a roll body which is formed on its periphery with a plurality of grooves, a plurality of tooth bearing segments detachably mounted on the roll body and each having an arcuate portion of which an outer surface cooperates with corresponding outer surfaces of the remaining rooth bearing segments to form an outer cylindrical surface of the roll, from which cylindrical surface teeth project radially outwardly, each said arcuate portion having an inner surface which fits closely the periphery of the roll body, and each tooth bearing segment being further provided with a radially inwardly extending projection which is engaged within a respective one of the grooves, characterised in that the tooth bearing segments are arranged side-by-side in rows extending along the grooves, are axially located in their operative positions by abutment means which are disposed at both ends of the roll body and maintain the tooth bearing segments in abutting side-by-side relationship, and are radially located in their operative positions by the interengagement of said projections in said grooves, the arrangement being such that, upon releasing at least one of the abutment means, the tooth bearing segments may be slid axially along the grooves into positions in which the projections are disengaged from the grooves, to permit removal of the tooth bearing segments from the roll in a direction radially of the roll.
Said grooves may extend parallel to the axis of the roll body. Alternatively, they may be dispoed helically on the roll body.
Said rows may extend parallel to the axis of the roll body, or alternatively, may be disposed helically on the roll body.
For each said row of tooth bearing segments, the locations of the teeth on the tooth bearing segments may be offset with respect to the axis of the roll body. Said locations may be so offset in an irregular pattern.
The roll body may be of one-piece construction. Alternatively, it may comprise a plurality of annuli arranged side-by-side. The length of each of said annuli may be substantially equal to the length of each of said tooth bearing segments, in a direction axially of the roll body. The annuli may be mounted on a common shaft, and both the annuli and the shaft may be provided with a keyway to permit movement of the annuli axially but not angularly of the shaft.
Endmost ones of the tooth bearing segments may be secured to the roll body, to provide at least one of the abutment means.
In a preferred arrangement, at least one of the abutment means comprises clamping half-rings which are secured to one end of the roll body.
The teeth may be integrally formed with the tooth bearing segments. In an alternative arrangement, the teeth may be in the form of removable picks, which are located in respective pick boxes formed in or provided on the tooth bearing segments.
Each of said projections may have a cross-section which substantially fills the cross-section of the respective groove.
Said grooves and/or said projections may be of substantially dovetail section.
Substantially the whole of the inner surface of said arcuate portion, other than said radially inwardly extending portion, may fit closely the periphery of the roll body.
According to a second aspect of the invention there is provided a roller crusher comprising a housing and a roll assembly mounted in bearings in the housing and definig a nip between the roll assembly and a further member, such that material may enter the nip and be crushed by the roll assembly, wherein the roll assembly is in accordance with the first aspect of the invention, and the roll assembly is so mounted in the housing as to afford between at least one end of the roll assembly and its respective bearing a spacing which is at least equal to the width of one of the tooth bearing segments such that, upon releasing the respective abutment means, the tooth bearing segments may be slid axially along the grooves into positions in which they may be removed from the roll assembly in a direction radially of the roll assembly, without removing the roll assembly from its bearings.
Such a roller crusher may comprise two said roll assemblies mounted for contra-rotation and adapted to co-operate with one another to define said nip.
The roller crusher may further comprise a wear plate which is detachably mounted on said housing to cover at least part of said spacing.
The invention will now be described by way of example with reference to the accompanying drawings in which:-

Figure 1 is a semi-diagrammatic perspective view of a roller crusher embodying the invention, with part broken away for clarity.
Figure 2 is a vertical section through one roll assembly of Figure 1, showing one construction of tooth bearing segment;
Figure 3 is a side elevational partial view similar to Figure 2, but showing tooth bearing member provided with pick boxes to accept conventional picks;
Figure 4 corresponds to Figure 3 but shows tooth bearing members formed to serve as pick boxes for conventional picks;
Figure 5 corresponds to Figure 1 but shows an alternative roll assembly construction; and
Figure 6 is a perspective view of one roll body forming annulus.

In Figure 1, a roller crusher comprises two contra-rotating roll assemblies 1, 2, the shafts 3, 4 of which are located in bearings at each end of the apparatus, the apparatus being provided with drive means for the roll assemblies within a housing generally indicated at 5. As is generally indicated in Figure 1 and more particularly in Figure 2, each roll assembly 1, 2 has a body provided with a number of longitudinally disposed parallel dovetail-like grooves 6, and tooth bearing members 12 are formed with dovetail-like projections 7 to fit in the grooves 6.
The teeth are so formed and located on the rolls that those on the roll face 1 face those on the roll 2, and such that when the rolls are located in the machine and caused to rotate, the teeth will grip and crush material falling into the nip of the rolls.
For each roll assembly 1, 2, a plurality of individual tooth bearing segments are provided, disposed side-by-side in rows along the grooves 6. As seen in cross-section in Figure 2, there are eight rows 6, and eight segments 12, spaced equally at 45° intervals around the periphery of each roll assembly 1, 2. Each segment 12 is formed with an integral tooth 11, or indeed more than one tooth if so required, and each segment 12 is formed with a respective dovetail-like projection 7 to fit in respective ones of the dovetail-like grooves in the roll body surface. With an abutment plate 9 secured at one end of the roll body, the requisite number of segments 12 can be slid onto the roll body from the opposite end, and another abutment plate 10 secured to the roll body to hold the segments 12 in position. As shown in Figure 1, each abutment plate 9, 10 may be secured to the end face of the roll body by means of screws which engage apertures in the roll body. The abutment plate 9 may, if desired, be fixed, and the plate 10 removable.
The apparatus illustrated in Figures 1 and 2 provides for the replacement of the teeth of the roll assemblies considerably more simply and with drastically reduced down time of the machine, in comparison with the prior art, such that segments with worn or damaged teeth may be replaced by new segments, with the roll assemblies in situ. Thus, the abutment plate 10 may be released, and slid along the shaft by a distance at least equal to the width of each segment 12. With, then, the abutment plate 10 spaced from the end of the roll body, the segments 12 can be slid along the roll body into the gap between the roll body and the plate 10, and then removed for replacement, radially of the roll assembly 1, 2.
It will be appreciated that, if the abutment plates 10 take the form of clamping half-rings, then each half-ring may be removed radially of the roll assembly 1, 2, after release from the end face of the roll body.
In the forms of construction shown in Figures 3 and 4, provision is made for the use of conventional point-attack picks as the teeth on the roll bodies. Thus, as is shown in Figure 3, each segment 12 may have secured to its outer periphery a relatively conventional pick-box 13 in which a point-attack pick 14 is located. In Figure 4, a still further alternative is shown where the segment 12 itself serves as the pick-box, by being formed with an appropriately shaped bore 15 angularly disposed within the segment 12 and in which the pick 14 can be located. With the constructions of Figure 3 and 4, in any instance where there is only wear or damage to the picks, they can simply be removed and replaced without the removal of the segments from the roll assembly, but there is the retention of the advantage that in any instance where there is wear or damage to both the pick and the segment, the segment can be removed as has been described above.
In Figure 1, the roll assemblies are so formed that the teeth (whether they be integral or formed by removable picks) are set in straight rows longitudinally of the roll. However, it may be advantageous for adjacent teeth in any one row to be offset. Thus, as is illustrated in Figures 5 and 6, each roll body is formed by a shaft 16 and a number of drum-like annuli 17 adapted to fit the shaft 16, each annulus at its periphery being formed with a number of parallel dovetail-like slots 6 to receive a number of segments 12, each provided with a corresponding dovetail-like projection 7. The centre bore 18 of each annulus is formed with a keyway slot 19 to locate it on the shaft 16 and by strategically positioning each keyway slot 19 on the number of annuli involved, adjacent annuli can be set on the shaft such that the teeth on the segments on the adjacent annuli are offset. The offsetting can be set to provide straight rows of teeth at any required angular disposition in relation to the shaft axis, to provide rows of teeth that are helically disposed along the length of the roll, or if desired, to provide a random distribution of teeth.
It will be appreciated that, in the arrangement shown in Figures 5 and 6, the individual annuli 17 may be moved their own length along the shaft 16, after removal of the abutment plate 10, to enable a gap to be formed between any two adjacent annuli 17, to allow the removal and replacement of tooth bearing segments 12, without disconnecting the roll assembly from its bearings.
There may be seen in both Figures 1 and 5 wear plates 8, which are detachably secured to the housing, to cover the clearance space between the respective end of the roll bodies and the housing, and therefore prevent oversized debris from falling through this clearance space, whilst the machine is working. Of course, it will be appreciated that, in order to remove and replace tooth bearing segments 12 on the roll bodies, the wear plates 8 are firstly removed.
In Figures 5 and 6, the tooth bearing segments 12 are of substantially the same width as the annuli 17.
Although, in the illustrated embodiments, each section shows eight tooth bearing segments 12 at 45° intervals, it will be appreciated that alternative configurations of tooth bearing segments may be provided. For example, in cross-section, there may be provided two tooth bearing segments each subtending an angle of 180°, and each having four projections 7 to fit the four corresponding grooves 6 in the respective roll body.
As an alternative to the abutments 9, 10 other means may be provided, such as, for example, locking endmost tooth bearing segments 12 to the respective roll body.
Each roll body, whether of one piece construction or formed from a plurality of annuli, may be formed by casting. Alternatively or additionally, the grooves 6 may be formed by suitable machining. Each roll body may be of a suitably tough material such as mild steel, keyed to a suitable, relatively small diameter, alloy shaft. The tooth bearing members 12 are preferably cast from a hard wearing and impact resistant tool steel, such as manganese steel.

Claims

1. A roll assembly for a roller crusher, the assembly comprising a roll body which is formed on its periphery with a plurality of grooves, a plurality of tooth bearing segments (12) detachably mounted on the roll body and each having an arcuate portion of which an outer surface cooperates with corresponding outer surfaces of the remaining tooth bearing segments to form an outer cylindrical surface of the roll, from which cylindrical surface teeth (11) project radially outwardly, each said arcuate portion having an inner surface which fits closely the periphery of the roll body, and each tooth bearing segment (12) being further provided with a radially inwardly extending projection (7) which is engaged within a respective one of the grooves, characterised in that the tooth bearing segments (12) are arranged side-by-side in rows extending along the grooves (6), are axially located in their operative positions by abutment means (9, 10) which are disposed at both ends of the roll body and maintain the tooth bearing segments (12) in abutting side-by-side relationship, and are radially located in their operative positions by the interengagement of said projections (7) in said grooves (6), the arrangement being such that, upon releasing at least one of the abutment means (9, 10), the tooth bearing segments (12) may be slid axially along the grooves (6) into positions in which the projections (7) are disengaged from the grooves (6), to permit removal of the tooth bearing segments (12) from the roll in a direction radially of the roll.

2. A roll assembly according to Claim 1, wherein said grooves extend parallel to the axis of the roll body.

3. A roll assembly according to Claim 1, wherein said grooves are disposed helically on the roll body.

4. A roll assembly according to Claim 1, 2 or 3, wherein said rows extend parallel to the axis of the roll body.

5. A roll assembly according to Claim 1, 2 or 3, wherein said rows are disposed helically on the roll body.

6. A roll assembly according to any. preceding claim, wherein, for each said row of tooth bearing segments, the locations of the teeth on the tooth bearing segments are offset with respect to the axis of the roll body.

7. A roll assembly according to Claim 6, wherein for each said row of tooth bearing segments, said locations are offset in an irregular pattern.

8. A roll assembly according to any preceding claim, wherein said roll body is of one-piece construction.

9. A roll assembly according to any of Claims 1 to 7, wherein said roll body comprises a plurality of annuli arranged side-by-side.

10. A roll assembly according to Claim 9, wherein the length of each of said annuli is substantially equal to the length of each of said tooth bearing segments in a direction axially of the roll body.

11. A roll assembly according to Claim 9 or 10, wherein said annuli are mounted on a common shaft.

12. A roll assembly according to Claim 11, wherein said annuli and shaft are provided with a keyway to permit movement of the annuli axially but not angularly of the shaft.

13. A roll assembly according to any preceding claim, wherein endmost ones of the tooth bearing segments are secured to the roll body, to provide at least one of the abutment means.

14. A roll assembly according to any preceding claim, wherein at least one of the abutment means comprises clamping half-rings secured to one end of the roll body.

15. A roll assembly according to any preceding claim, wherein the teeth are integrally formed with the tooth bearing segments.

16. A roll assembly according to any one of Claims 1 to 14, wherein the teeth are in the form of removable picks, located in respective pick boxes formed in the tooth bearing segments.

17. A roll assembly according to any one of Claims 1 to 14, wherein the teeth are in the form of removable picks, located in respective pick boxes provided on the tooth bearing segments.

18. A roll assembly according to any preceding claim, wherein each of said projections has a cross-section which substantially fills the cross-section of the respective groove.

19. A roll assembly according to any preceding claim, wherein said grooves are of substantially dovetail section.

20. A roll assembly according to any preceding claim, wherein said projections are of substantially dovetail section.

21. A roll assembly according to any preceding claim, wherein substantially the whole of the inner surface of said arcuate portion, other than said radially inwardly extending projection, fits closely the periphery of the roll body.

22. A roller crusher comprising a housing and a roll assembly mounted in bearings in the housing and defining a nip between the roll assembly and a further member, such that material may enter the nip and be crushed by the roll assembly, wherein the roll assembly is in accordance with any one of the preceding claims, and the roll assembly is so mounted in the housing as to afford between at least one end of the roll assembly and its respective bearing a spacing which is at least equal to the width of one of the tooth bearing segments such that, upon releasing the respective abutment means, the tooth bearing segments may be slid axially along the grooves into positions in which they may be removed from the roll assembly in a direction radially of the roll assembly, without removing the roll assembly from its bearings.

23. A roller crusher according to Claim 22, comprising two said roll assemblies mounted for contra-rotation and adapted to co-operate with one another to define said nip.

24. A roller crusher according to Claim 22 or 23, further comprising a wear plate which is detachably mounted on said housing to cover at least part of said spacinq.