TECHNICAL FIELD The present invention concerns a device at cas¬ settes for spring members for a machine e.g. a sweeping machine, which in one embodiment can be proposed i.a. for removing of rubber rests, snow and ice from runways for aircrafts, at which spring members are manufactured of steel, and which in another embodiment can be proposed for removing snow from railway tracks and switches,--at which the spring members are manufactured of plastic. Thus the device is usable at sweeping machines for seve¬ ral different purposes. The cassettes are arranged around the periphery of a rotatable roller and extending mainly in the longitudinal direction of the roller and including units of spring members, as radially extending bristles, which ends are brought in contact with the ground, e.g. a runway, at the rotation of the roller. Each cassette in- eludes a longish bar, which is arranged in facing grooves in brackets which extend along the length of the roller. BACKGROUND TECHNICS

A great number of solutions are known for faste¬ ning of cassettes for bristle bunches arranged around the periphery of a bristle roller, which in its turn is ro- tatably mounted on a sweeping machine or the similar. The Swedish patent publication SE-B-.21 331 describes a bristle roller which shows longish cassettes in which bunches of bristles are arranged in openings along the length of each cassette. Each cassette is acco odated in grooves extending along the length of the bristle roller and is constituted by two facing U-shaped sheet profiles, which show facing openings, in which bristle bunches are arranged with radially projecting bristles. The sheet profile in the cassette by its weight here constitutes a disadvantage as the cassette is exposed to big mass for¬ ces at the rotation of the bristle roller.

Another embodiment of a bristle roller is known by the American patent publication US 4,538,319. A cas¬ sette similar to the one which is described in the patent publication ^' SE-B-421 331 here is arranged between brac- kets which in its turn are attached to a longish roller. The brackets show grooves for sliding lists, which in its turn show sliding grooves in which the cassettes are ac¬ commodated. The sheet profiles in the cassette also here make a disadvantage as their weight make them awkward and giving rise to non desirable mass forces at the rotation of the bristle roller. The present invention i.a. consti¬ tutes an improvement of the device according to US 4,538,319 and is described below. DESCRIPTION OF THE INVENTION The purpose with the present invention is to achieve a device according to the preamble above, which constitutes an improvement of a cassette for spring mem¬ bers which is possible to use at a bristle roller similar to the one described in the patent publication US 4,538,319. The device includes a rotatable roller carrying brackets for the cassettes including units of spring members. Each cassette includes a longish bar, which is arranged in facing grooves in the brackets ex¬ tending along the length of the roller. The invention is characterized in that passages for e.g. removed material, other dustes and water are ar¬ ranged between each groove and the bar extending in the grooves. In a special embodiment of the invention the passages are constituted by a continuous gap or one or more parts of gaps extending along adjacent surfaces on each groove and bar in the cassettes.

By the arrangement of gaps mentioned above a self-cleaning of the rotor with cassettes for spring members has been achieved, at which a clogging of pollu- sions and the similar between the roller and the under¬ side of the cassette has been avoided as between the bar and the grooves in which it is extending. By the

arrangement of a gap in this way the work with exchange- ment of the cassettes is facilitated e.g. after the spring members in the same have been weared out. As the device, which is described in the patent publication US 4,538,319, the brackets for the cassettes preferably are provided with sliding bars, showing grooves in which the cassettes are accomodated. In the device according to present invention each cassette also shows a bar of plas¬ tic, which partly makes the manufacturing of each cas- sette cheaper, partly facilitates the insertion respec¬ tively removal of each cassette at exchange. Further the bar shows opening for bunches of spring members along its radially out-turned side, which also is provided with a metallic cover. Preferably the cover is constituted by a sheet, preferably a steel sheet, which shows edges which are bent mainly radially inwards to the center axis of the roller. Further the cover plate preferably shows col¬ lars projecting downwards in openings in the bar. By the cover plate and its edges and collars a reinforcement of the bar against deformation by the forces arising at using of the rotor is reached. Further a better wear re¬ sistance for the pollution passing in the gap between the bar and the corresponding grooves in each bracket of the rotor roller is reached. In an alternative embodiment of the invention the sliding bars in the brackets can be excluded when the bar of the cassette is made of plastic, at which an addi¬ tional increase of the wear resistance to passing pollu¬ tion and other particles is reached. The insertion and removal of the cassette in this case is facilitated by the plastic in the bar and its eventually concentrated contact to the grooves in the brackets.

Further characteristics of the invention will be clear from the description to drawings below and the en- closed claims.

DESCRIPTION TO DRAWINGS

The invention is described below as an

embodiment according to the enclosed drawings.

Figure 1 fragmentary shows a rotor with casset¬ tes carrying spring members in a cross section to the longitudinal direction of the rotor. Figure 2 shows a part of a cassette with spring members mounted in brackets extending along the length of the rotor.

Figure 3 shows a sliding list to each bracket in a cross section. Figure 4 shows a part of a spring member enlarged.

Figure 5 shows a mounting of spring members in a part of a cassette.

Figure 6 shows a cross section through the cas- sette with spring members along the line A-A in figure 5. Figure 7 separately shows a cover plate to the cassette with spring members according to figure 5 and 6.

Figure 8 shows an alternative embodiment of a cassette in a longitudinal section and without spring members.

Figure 9 shows the cassette according to figure 8 in a view from above.

A rotor for e.g. a sweeping machine comprises a cylinder-shaped, longish roller 1 which carries brackets 2 for longish cassettes 3 with spring members 4 extending along the length of the roller 1 and are arranged close to each other along the periphery of the roller 1. Two adjacent brackets 2 is shown in figure 1 and enlarged in figure 2. The brackets 2 are kept to the roller 1 by means of wedge members 5 which are situated between each bracket 2 and equally spread along the length of the rol¬ ler 1. These bracket 2 and belonging wedge members 5 are known earlier from the patent publication US 4,538,319 which is mentioned above. The brackets 2 show grooves 6 on each side, extending along the full length of each bracket 2, in which sliding lists 7 of plastic are arranged. The sliding lists 7 show facing rectangular

sliding grooves 8 in which a cassette 3 is accomodated and thereby filling up the space between two brackets 2. A gap 8.1 is arranged between each sliding bar 7 and the intermediate cassette 3. Each cassette 3 includes a bar 9 of plastic, which shows mainly cylinder-shaped, cup-shaped means (cups) 10 equally spread along the length of the bar 9. The cups 10 in its turn carries sections of mutually connected cages 11, which are brought into the cups 10 and in which spring members 4 are collected in a way ma¬ king their free ends projecting from each cage 11. The number of projecting spring members 4 in each cage 11 is 100 - 400 and has a diameter of 0,1 - 2,0 mm, particular¬ ly 0,3 -1,0 mm. Each spring member 4 is constituted by a steel wire showing a characteristic diameter (d), waves with a wavelength (1) and a waveheight (h) as shown in figur 4 and with the following dimensiones: 1 = (2 to 20) x d, particularly max 5 x d, h = i (1,5 to 3) x d. A bar 9 to a cassette 3 is shown in a section in figure 5 and in a cross section in figure 6. The bar 9 which is shown in the figures shows a mainly rectangular downwards open cross section. The cups 10 are arranged projecting down from the upper side of the bar 9 and are provided with a bottom 10.1. Between the cups 10 two mu¬ tually parallel supporting walls 10.2 extend, which part¬ ly serve as a stiffener of the bar 9, partly constitute a guide for a locking wire 10.3 which at mounting of the cages is brought through holes in facing sides of the cups 10 and through cages 11 with spring members 4 which are brought down into the cups 10. Further the cages 11 are provided with uppwards projecting basket-like means (baskets) 12, which in its turn are mutually connected with a connecting wall 13. The bar 9 with the cups 10 and the cages 11 with spring members 4 attached therein is known earlier as well as the device to lock the parts together to a cassette 3 -

The bar 9 shown in figure 5 and 6 further is provided with a cover plate 14, which shows edges 14.1, which are bent mainly radially inwards to the roller 1 along the two parallel sides of the bar 9, and collars 14.2 projecting down into the openings at each cup 10 in the bar 9. Preferably the cover plate 14 is constituted by a steel sheet, which increases the stiffness of the bar 9 and its capacity to take up forces from the spring members 4 when they rotate with the rotor and are brought in contact with the ground. A separate cover plate 14 is shown in figure 7 from below. The cover plate 14 can ex¬ tend over the full length of the bar 9.

In an alternative embodiment of the invention, which is shown in figure 8 and 9, the cassette 3 shows a bar 9 of plastic as above, but which is provided with se¬ veral cover plates 14 arranged with a mutual distance. In the embodiment shown each part-cover plate 14 comprises four cages 11 with spring members 4 put together in one unit by the connecting walls 13 mentioned. At each dis- tance the bar shows a projecting party 15 projecting from the surface of a cover plate about 0,2 mm, by which par¬ ties 15 the bar 9 can be pushed into the sliding lists 7 without the cover plate coming in contact with the same. At each end of the bar 9 a projecting party 15.1 is ar- ranged. An insertion of a cassette 3 in the brackets 2 by this can .be made with a very low friction resistance and eventually burrs on the cover plate 14 is prevented from damaging the sliding lists 7. The projecting parties 15 are weard out during the work of the roller 1. In this embodiment of the invention the sliding lists 7 of plas¬ tic can be excluded by that each cassette 3 can slide on the projecting parties 15, 15.1 at insertion in the brac¬ kets 2 on the roller 1.

In another alternative embodiment of the inven- tion, not shown in the figures, the cover plate 14 can be replaced by a collar-like reinforcement projecting down into the bar on each oassette. This embodiment is usuable

at proportionally low strains on the spring members as e.g. at easy sweeping works.

The embodiments of the invention described give a very solid cassette which permits high rotation speed of the roller in use. A roller of a diameter of 300 mm can be given a rotation speed of 600 - 1000 r/min, which corresponds to a periphery speed of about 600 1000 m/min.