GB2026342A

GB2026342A - Improvements in or relating to crushing machines

Info

Publication number: GB2026342A
Application number: GB7920693A
Authority: GB
Original assignee: Engelbrecht & Lemmerbrock; Engelbrecht and Lemmerbrock GmbH and Co
Current assignee: Engelbrecht & Lemmerbrock; Engelbrecht and Lemmerbrock GmbH and Co
Priority date: 1978-05-04
Filing date: 1979-06-14
Publication date: 1980-02-06
Also published as: GB2026342B

Abstract

This invention relates to crushing machines of the kind comprising a housing containing two shafts which are drivable so as to counter- rotate, said shafts being fitted with alternate cutters 4, 5 and spacers 6, 7, said cutters having projections spaced around the shaft circumference with recesses therebetween in such a manner that the cutting edges of the projections and the recesses of the one shaft slightly overlap those of the other shaft. According to the invention, each shaft 2, 3, is provided with a large number of axially parallel teeth 2a, 3a, extending over the entire cutting length and the inner circumference of all similar cutters and spacers has the same number of similar axially parallel teeth 4a 5a. <IMAGE>

Description

SPECIFICATION Improvements in or relating to crushing machines The present invention relates to crushing machines and particularly to the cutters and spacers for same, of the kind comprising a housing containing two shafts which are drivable so as to counter-rotate, said shafts being fitted with alternate cutters and spacers, said cutters having projections spaced around the shaft circumference with recesses therebetween in such a manner that the cutting edges of the projections and the recesses of the one shaft slightly overlap those of the other shaft. Hereinafter, such a crushing machine will be referred to as "of the kind described".

In known machines for crushing bulky material, for example tin, wood, paper, plastics or similar material, various methods of mounting the cutters such as cutting blades are mentioned.

According to one method shafts of polygonol shape are used having suitable apertures into which the cutters are inserted; however very high pressures on the edges which result from this operation represent a considerable disadvantage which it would be desirable to avoid.

According to another method of mounting, the cutters are provided at one end with blind bores and at the other end with corresponding lugs so that the lugs of one cutter fit into the blind bores of the next cutter whilst the first and last cutters are so attached to the shaft that the shaft is toothed here and is brought into toothed engagement with the toothing of the first and last cutter. As the projections of the cutter are successively offset by a small peripheral angle so as to obtain a helix of the top edges of the projections for a better cutting distribution for bulky materials it was possible to make all the cutters identical. An assembly with groove and adjusting spring with identical cutting tools should however have an adjusting spring groove offset in the shaft milled for each blade.In this instruction the cutters could only be mounted on detachable shafts as the first and last blades should have a smaller bore than the remaining blades due to the toothing. If the shafts are provided with a continuous adjusting spring groove, each cutter must be provided with an offset adjusting spring groove i.e. the cutters vary in construction.

It is an object of the invention to simplify and facilitate the mounting of the entire cutters in the two cutter shafts and also possible spacers beween the cutting bodies.

Accordingly the invention consists in a crushing machine of the kind described wherein each shaft is provided with a large number of axially parallel teeth extending over the entire cutting length and the inner circumference of all similar cutters and spacers has the same number of similar axially parallel teeth.

This construction enables each cutter to be simply pushed onto its appropriate shaft and secured in relation thereto against rotation it being possible before pushing the cutter onto the shaft by simple circumferential relative rotation to ensure that the successive cutters have their leading edges of their projections offset around the shaft circumference so as to obtain a helical disposition of these leading edges. Since all the cutters and spacers are completely identical it is possible to change them over at any desired position along the shaft.

To put on and to remove the cutting bodies and spacing elements from the shafts it is only necessary to remove the end wall of the rectangular housing facing the shaft drive with two shaft bearings from the shafts so that the ends of the shafts are freely accessible here.

In order that the invention may be more clearly understood reference will now be made to the accompanying drawings which show one embodiment thereof by way of example and in which: Figure 1 is a schematic cross-section through a rigid rectangular housing of the crushing machine accommodating the cutting mechanism without the inlet and without the lower outlet which is provided with a sieve.

Figure 2 is a longitudinal section along the line ll-ll of Fig. 1 through the shaft which is fitted with cutters, Figure 3 is an enlarged side view of a cutter, and Figure 4 is a section along the line IV-IV of Fig. 3.

Referring now to the drawings, there is shown a crushing machine comprising a rigid rectangular housing 1 forming part of a main casing. At one end for example is arranged a gearbox 1 a screwed into the housing 1 and two counter-rotatable shafts 2, 3 are carried by said gearbox, passing through suitable apertures in the limiting wall of the housing so as to run freely therethrough but be freely accessible for fitting purposes by removing the opposite end wall 1 b of the housing 1.

These two shafts 2 and 3 are provided on their circumferences and along their entire length between the end walls of the housing 1 with a large number of axially-parallel longitudinally-extending teeth which are shown at 2a and 3a. The spacing of the teeth from each other, for a number determined according to DIN standards is for example, 8.7 with respect to the shaft axis.

The inner bore of each cutter 4, 5 and any spacer 6, 7 is provided with the same number of identical axially-parallel teeth 4a, 5athe cutters 4, 5 which have flat end faces 8, 9 being provided in this embodiment with a cutting edge 1 3 of hard material around the entire circumference of the equally divided protrusions 10, 11 which are flush with the end faces, and also around the recesses 1 2 between them.

Due to the internal toothing 4a, 5a of the cutters 4, 5 and the spacers 6, 7 these can be easily pushed onto the longitudinally toothed shafts 2, 3 and are thus clearly secured against rotation.

As all the cutters 4, 5 and spacers 6, 7 are completely identical with each other it is possible to stagger the successive cutters 4, 5 on the two shafts around the circumference by an amount represented by the space of at least one tooth for example by 8.7. and then in this position to push on the shafts 2, 3 so that the leading edge of the projections 10, 11 pulling in the material lie practically on a helix.

According to the embodiment the leading edges of the projections 10 and 11 of the two series of projection circumferences of each cutter are already offset to each other by one tooth for example by 8.7 according to the circumference.

After pushing all the cutters 4, 5 and spacers 6, 7 on to the two shafts 2, 3, the end wall 1 b with the shaft bearings is pushed onto the ends of the shafts and is screwed to the rectangular housing whereupon a nut, which presses the cutters 4, 5 and the spacers 6, 7 axially together by means of a spacing ring, is screwed onto the ends of the shafts.

Claims

1. A crushing machine of the kind described wherein each shaft is provided with a large number of axially parallel teeth extending over the entire cutting length and the inner circumference of all similar cutters and spacers has the same number of similar axially parallel teeth.

2. A crushing machine as claimed in claim 1, wherein the cutters succeeding each other on the two shafts are pushed onto the circumference of the shaft, each relatively offset by at least one tooth.

3. A crushing machine as claimed in claim 1 or 2, wherein the cutters each have a flat end face vertical to the axis of the shaft, and are provided on the circumference with two sets of projections flush with the front face and recesses between them of which the projections of the one set are offset, by at least the angular spacing of one tooth with respect to the shaft, to those of the other set.

4. A crushing machine as claimed in claim 1, 2 or 3, wherein the circumferential offset of the cutters or the leading edge of their projections, on each shaft is 8.7 .

5. A crushing machine as claimed in claim 1, 2 or 3, wherein all the cutters and spacers can be removed or pushed onto the one end of the two shafts which is easily positioned with its bearing by detaching an end wall of the housing.

6. A crushing machine substantially as hereinbefore described with reference to the accompanying drawings.