EP0368759B1 - Rotor for a hammer mill - Google Patents

Description

The present invention relates to a hammer crusher rotor, in particular a crusher rotor used for shredding metallic or composite objects, such as the carcasses of motor cars or household appliances.

The crushers targeted by the invention comprise a fixed casing housing a rotor whose central drive shaft carries several flanges. Hammers are pivotally mounted between the flanges, on eccentric axes passing through these flanges parallel to the central shaft.

The internal walls of the fixed casing comprise an anvil-forming part which contributes with the hammers of the rotor to shred the metallic objects brought in by a feed ramp. The rotor shaft is coupled to a motor which drives it at such a speed that the hammers perform the shredding work, under the cumulative effect of their kinetic energy and the centrifugal force which energetically returns them to the position of maximum radial distance from their center of gravity.

To prevent the periphery of the discs from being subjected to high wear by abrasion and impact, it is known to surround the discs with removable protective plates of steel of wear and impact resistant grade.

According to FR-A-2 522 536, these plates are removable caps covering only the periphery of the flanges, to which they are fixed by means of screws. These caps are complicated to make, their assembly is long and tedious because using very many screws which in addition, in service, are exposed to contact with objects being shredded. In addition, these caps do not close the spaces between flanges.

According to FR-A- 2 304 404 and DE-A- 35 24 725, the protective plates together constitute a sleeve completely covering the side wall of the rotor with the exception of passages provided for hammers. According to DE-A-35 24 725, the elementary protective members are two half-shells comprising the notches necessary for the passage of the hammers. According to FR-A-23 04 404, the elementary protective members are tiles arranged in axial rows each associated with one of the hammer-carrying shafts. Each tile has an axial dimension corresponding to the step of succession of the flanges. According to the two documents, the protective members have on their internal face retaining ears engaged between the flanges and each crossed by one of the hammer-carrying axes.

The protective members known from FR -A-2 304 404 or DE-A- 35 24 725 have drawbacks. These are parts produced for example by molding, therefore costly to manufacture, in particular in the case of half-shells (DE-A). In the case of FR-A-23 04 404, the weight of the ear required for each protective tile considerably increases the rotor, and therefore increases its cost price. In the two known devices, the centrifugal force undergone by the protective members is transmitted to the rotor structure by the hammer-carrying shafts, which increases the loading undergone by them and promotes wear of the bores of the flanges.

According to US - A - 3,727,848, the protective members are caps covering the end of the hammer-carrying arms. These caps are also provided with an ear crossed by the hammer-carrying shaft. These ears are provided with conformations which interact with complementary conformations of the arms to ensure restraint with regard to centrifugal force. However, the protection is even more localized than according to FR - A - 2 522 536, and the parts (caps and arms) are very complex.

The object of the invention is to overcome the above drawbacks and more particularly to rationalize the protective elements and the structure by which they are associated with the other elements of the rotor.

According to the invention, the hammer crusher rotor, intended in particular for shredding cars or household appliances, comprising flanges fixed at an axial distance from each other along a motor shaft of which they are integral in rotation, these flanges supporting eccentric shafts parallel to the drive shaft, while a hammer is mounted oscillating on one of the eccentric shafts in each space between two successive flanges, and that protective covers covering the periphery of the flanges partially close the periphery of the rotor by defining between them passages for the hammers, is characterized in that each cover has, on the side facing the motor shaft, engagement conformations with complementary conformations formed at the periphery of the flanges, these conformations being oriented axially to allow the axial sliding of the cover, and having in cross section shapes such that they r radially hold the hood.

Thus, the protective covers are retained directly by the flanges with respect to the centrifugal force. This load is therefore no longer transmitted by the hammer carrier shafts, and is no longer supported by the bores provided in the flanges for the hammer carrier shafts. In addition, the amount of material required to achieve the radial attachment between the protective covers and the flanges can be limited to the minimum strictly necessary from the mechanical point of view, and the mass gained can be transferred to the hammers to make them even more effective. . On the contrary, in this regard, the ears of the prior art are far from optimal since only their end portions located beyond the associated hammer-carrying shaft is effective, the rest of the ear having a role of transmission of the retaining force between said end portion and the tile or the protective half-shell. The mounting of the protective covers by axial sliding according to the invention is very convenient. In addition, the covers may consist of sections of section cut to length. Their manufacture is then very economical, and assembly is facilitated because the number of covers can then be considerably reduced: each group of successive inter-flange intervals in which a hammer-carrying shaft carries no hammer can be covered by a single cover of appropriate length.

Other features and advantages of the invention will emerge from the description below.

• la figure 1 est une vue partielle en perspective montrant schématiquement un rotor de concasseur à marteaux conforme à l'invention ;
• la figure 2 est une vue partielle en élévation longitudinale du rotor de la figure 1, partiellement en coupe selon le plan II-II de la figure 3 ;
• la figure 3 est une vue en coupe transversale selon le plan III-III de la figure 2 ; et
• la figure 4 est une vue illustrant schématiquement le montage du rotor.

In the appended drawings, given by way of nonlimiting examples:

• Figure 1 is a partial perspective view schematically showing a hammer crusher rotor according to the invention;
• Figure 2 is a partial view in longitudinal elevation of the rotor of Figure 1, partially in section along the plane II-II of Figure 3;
• Figure 3 is a cross-sectional view along the plane III-III of Figure 2; and
• Figure 4 is a view schematically illustrating the mounting of the rotor.

As shown in Figures 1 to 3, the rotor 1 comprises a central drive shaft 2 supported by bearings 3 and driven by a motor not shown. On the shaft are fixed coaxially with it several flanges 4 in the form of discs arranged at regular axial intervals from one another. There are nine disks 4 in the example. Each disc 4 is crossed by four bores 5 located at equal radial distance from the shaft 2 and distributed at regular angular intervals (90 °) around of the axis of the central shaft 2. Each bore 5 of a disk 4 has a common axis with a bore 5 of each of the other disks 4, an axis which is parallel to the axis of the central shaft 2. Each row of coaxial bores is traversed by a hammer-carrying shaft 6 parallel to the shaft 2 and eccentric with respect thereto. In each interval between two neighboring discs 4, one and only one of the hammer carrier shafts 6 carries a hammer 7 which can pivot freely around said hammer carrier shaft. To this end, each hammer 7 has a through bore 17 in which the associated hammer-carrying shaft 6 is threaded.

Protective covers 8 cover the periphery of the discs 4 and the interdisc spaces, while providing the right of each interdisc space, an opening 18 for the corresponding hammer 7.

In the example shown comprising four hammer-carrying shafts, each cover has an outer surface in the form of a quarter cylinder. The covers are aligned in four axial rows each associated with one of the hammer-carrying shafts. Each cover is arranged symmetrically with respect to a plane passing through the axis of the associated hammer-carrying shaft, and through the axis of the central shaft 2. In each row, the successive covers have between them an axial interval defining one of the openings 18.

Each cover 8 has two opposite longitudinal flanges 11, bent towards the shaft 2 and engaged in corresponding notches 13 formed in the periphery of the discs 4. There are four notches 13 at the periphery of each disc, angularly distributed at 90 ° the each other around the axis of the shaft 2. Each notch 13 is located at equal angular distance, measured around the axis of the shaft 2, of two successive bores 5 of the same flange. The two side walls 14 of each notch 13, located on either side of a bottom wall 16, are parallel to each other and symmetrical with respect to an axial plane 19. This makes the notches 13 very easy to produce, in particular thanks to the absence of undercut. Each notch 13 receives in service two flanges 11 belonging to two covers 8 succeeding each other in the circumferential direction.

Thanks to their different angular position around the shaft 2, the notches 13 define between them bosses 21 in the form of a dovetail (FIG. 3) each delimited by two walls 14 and by the periphery in the form of a cylindrical sector which presents each disc between two successive notches. Thus, each disc has on its periphery four dovetail bosses 21 separated by four notches 13. In service, each boss 21 is engaged in a recess of corresponding shape of a cover 11, recess defined by the inner faces of the two edges 11 and by the cylindrical inner face of the cover. This interengaging of the boss 21 in the correspondingly shaped recess of the cover effectively retains the cover 8 with regard to any movement of radial distance from the shaft 2.

The two flanges 11 received in each notch 13 fill the latter almost completely, apart from the assembly clearances. In service, under the effect of the centrifugal force exerted on each cover 8, the flanges 11 are biased, by a bending force tending to separate them from one another to escape the notches 13. However, thanks when the notches are completely filled, the flanges 11 do not have the space to bend enough to escape radially outwards.

The notches 13 of the successive discs are aligned along four axial lines. The covers 8 are profiled sections, each of which is cut to the desired length taking into account the axial positions where it is desired to make the openings 18 in order to house a hammer 7 there (in the example shown, when considering the entire rotor, the openings 18 are arranged along a propeller). Thus, some of the covers 18 cover several interdisc spaces. Between two axially aligned openings 18, or respectively each opening 18 and the adjacent axial end of the rotor, there is always only one cover 8 of suitable length. The flanges 11 can therefore, depending on the length of the cover to which they belong, occupy several successive notches 13 aligned axially.

The successive covers 8 of the same axial row have edges 23 towards each other which define between them one of the openings 18 and which project into the interdiscal space associated with this opening. Thus, the flanges 11, which extend over the entire axial length of each cover 8, even occupy the notches 13 adjacent to the openings 18. In addition, the hammers 7, which are mounted with the possibility of sliding along the carrier shafts hammers 6 are positioned axially by the two edges 23 between which they are mounted.

The interengagement of the flanges 11 and the notches 13 is, by itself sliding parallel to the axis of the motor shaft 2. In particular, during assembly, the covers 11 are mounted by sliding from one end of the rotor, parallel to the axis of the motor shaft 2.

More particularly, as shown in FIG. 4, for mounting, after having assembled the discs 4 on the shaft 2, the covers 8 are slidably engaged on the discs, distributing them over the length of the rotor so as to form the openings 18 at the locations provided. Then, a hammer-carrying shaft 6 is threaded into the row of bores 5 associated with the hoods in place, while presenting in each opening 18 of this row the corresponding hammer 7 so that the hammer-carrying shaft 6 also passes through the bore 17 of this hammer. We see in Figure 4 a hammer 7 already crossed by the shaft 6 and a hammer 7 that is being brought to an opening 18 that will reach the front end from shaft 6 being threaded.

FIG. 4 shows the assembly of a row of hoods and hammers, and the assembly of the corresponding shaft 6. The same is done for the other rows. One can, as a variant, set up all the covers beforehand, then successively set up the shafts 6 and the hammers of each row. According to another variant, it is possible to successively put in place in each row a cover, a hammer, a cover, etc.

The blocking of the assembly is ensured, at each end, by four stop plates 22, each of which is fixed by two nuts 10, therefore in a removable manner, to the external face of the terminal disc so as to close one of the bores 5 from this disc and to project radially outward to prevent the adjacent cover from escaping axially.

The considerable simplifications provided by the embodiment which has just been described result from the fact that the covers, while being of very simple structure, are reduced in number and are assembled by simple axial sliding without any other locking means than locking. of each axial row at its two ends.

Of course, the invention is not limited to the example described and shown.

In particular, the number of hammer-carrying shafts and the number of hammers may be different.

Claims (9)

1. A rotor for a hammer crusher, intended inter alia for crushing motor vehicles or domestic appliances, comprising plates (4) fixed at an axial distance from one another along a drive shaft (2) to which they are connected for rotation, the plates supporting eccentric shafts (6) parallel to the drive shaft, while a hammer (7) is mounted oscillatorily on one of the eccentric shafts in each space between two successive plates, protective covers (8) which cover the periphery of the plates partially closing the periphery of the rotor and defining between them passages (18) for the hammers, characterised in that each cover (8) has, on the side facing the drive shaft (2), formations (11) for inter-engagement with complementary formations (13) provided on the periphery of the plates, said formations (11, 13) being oriented axially to allow axial sliding of the cover, and having in cross-section shapes such that they radially retain the cover.
2. A rotor according to claim 1, characterised in that the formations (13) on the periphery of the plates (4) comprise notches distributed angularly between the eccentric shafts (6), and define between them, at the periphery of the plates, dovetail-shaped projections (21) which in operation engage in recesses of corresponding shape in the covers (8).
3. A rotor according to claim 1, characterised in that the formations of the covers (8) comprise rims (11) bent towards the drive shaft, and in that the formations on the periphery of the plates comprise notches (13) each designed to receive side by side two such rims (11) belonging to two covers (8) disposed successively in the circumferential direction.
4. A rotor according to claim 2 or 3, characterised in that each notch (13) has, on either side of a bottom wall (16), two walls (14) which are substantially parallel to one another and symmetrical with respect to an axial plane (19).
5. A rotor according to any one of claims 1 to 4, characterised in that the formations (13) on the successive plates correspond to one another in an axial direction so as to form together, for the covers (8), slideways extending over the entire axial length of the rotor.
6. A rotor according to any one of claims 1 to 5, characterised in that each eccentric shaft (6) is associated with an axial row of protective covers (8), and in that along each row, each of the axial gaps between the hammers (7), and between a hammer (7) and an axial end of the rotor, respectively, is occupied by a single protective cover of appropriate length.
7. A rotor according to any one of claims 1 to 6, characterised in that the protective covers (8) are profiled elements cut to length.
8. A rotor according to any one of claims 1 to 7, characterised in that the hammers (7) are axially positioned by abutting against edges (23) of the protective covers (8).
9. A rotor according to any one of claims 1 to 8, characterised by demountable end abutments (22) which, relatively to an outside surface of each of two end discs of the rotor, limit the axial deflection of the eccentric shafts (6) and of the protective covers (8).

Images