The invention relates to a brush cassette, which is intended, together with several similar brush cassettes, to form the brush of a sweeper, which brush cassette includes

- an elongated profile,

- a wire bundle for sweeping, consisting of individual brush wires, each brush bundle of which has a first end and a second end, of which the first end is attached to the profile,

- conduit-like support parts, comprising a first end for attaching the wire bundles by their first ends consecutively to the profile, and a second end, which support part widens in the direction away from the profile, to permit the spreading of the brush wires of the wire bundle.

The invention also relates to a corresponding bushing for the brush cassette.

The cleaning of runways at airports is of primary importance for the safety of air traffic. Cleanliness is maintained by cleaning the runways using work machines, in which brushes are used. Traditionally the brushes' wire bundles are attached di rectly to the brush body, so that when the brush wears, the entire brush together with the body must be replaced. In tra ditional brushes, the number of brush wires to the surface area was large and their durability was good, but the work of re placing them was difficult.

Nowadays, brushes consist of individual brush cassettes, which are in turn constructions consisting of wire bundles arranged in rows. The advantage of such a construction compared to a traditional brush is their easy replaceability, as worn brush cassettes can be replaced without detaching the brush body. The drawback of brush cassettes, however, is their limited number in the brush drum, and thus their more rapid wearing, the number of individual wires being smaller.

The cleaning effect of the brush also depends on the number of wire bundles in an individual brush cassette, i.e. on how many brush wires there are in each brush. The number of wire bundles in a brush cassette, in turn, limits the longitudinal surface area of the profile required by the bushings used to attach the wire bundles. In other words, only a limited number of wire bundles can be set in a row in the profile, the free ends of which touch each other and partly overlap at the sides, the bushings being tightly against each other. Publication EP 1534498 B1 discloses such a brush cassette. In such a solution, the shape of the bushing determines over how wide an area the ends of the individual brush wires in the wire bundle spread and how close the bushings, and therefore the wire bundles, can be set in the brush cassette.

The cleaning effect of the brush can also be increased by raising the speed of rotation of the brush or by increasing the pressing of the brush, but this increases the brush's wear.

The invention is intended to create a more durable and effective brush cassette than brush cassettes of the prior art, in which there are more brush wires to the surface area. The character istic features of the present invention are stated in the ac companying Claim 1. The invention is also intended to create a bushing for brush cassettes, with the aid of which more brush wires are obtained than with bushings of the prior art to the surface area in the brush cassette. The characteristic features of this invention are stated in the accompanying Claim 11.

This intention can be achieved by means of a brush cassette, which is intended, together with several similar brush cassettes, to form a sweeper's brush, which brush cassette includes an elongated profile, wire bundles consisting of sev eral individual brush wires for sweeping, of which each wire bundle has a first end and a second end, of which the first end is attached to the profile, and a conduit-like support part, consisting of a first end for attaching the wire bundles by their first ends to the profile consecutively, and a second end. The support part widens away from the profile to permit the spreading of the brush wires, and at least in the case of the second end the shape of the cross-section is greater in the first direction than in the second direction, which is perpen dicular to the first direction, in order to spread the brush wires of the wire bundle in the first direction and to narrow them in the second direction.

In other words, the support part has at least at the second end a flattened cross-sectional shape in a direction of ±45° to the profile, to spread the wire bundle's brush wires in the selected direction and to narrow them perpendicularly to the selected direction .

By means of such a flattened construction of the wire bundles, more wire bundles can be fitted into the length of the profile than by the consecutive setting of the traditional wire bundles, in which the width of the wire bundles in the direction of the profile acting as a limiting factor. The larger number of wire bundles permits a greater sweeping efficiency. The greater num ber of wire bundles also means that more wire bundles are simultaneously in contact with the object being swept, so that the wear of an individual brush wire is reduced and the service life of the brush cassette increases.

The first direction of the support part in the brush cassette is preferably perpendicular to the longitudinal direction of the profile and the second direction is parallel to the longi tudinal direction of the profile. Thus the space taken by an individual wire bundle in the longitudinal direction of the cassette diminishes, whereas it grows in the transverse direc tion thus permitting the use of a greater number of wire bundles in the cassette.

The second direction can alternatively also be at a ±45° angle relative to the profile's longitudinal direction, the first direction then being perpendicular relative to the second di rection .

According to one embodiment, the width of the support part's second end in the first direction is 110 - 300 % of the width of the first end. The wires can then be spread in a wide area in the first direction, whereas in the second direction the width remains small.

According to one embodiment, the width of the support part's second end in the second direction is 100 - 200 % of the width of the first end. The wires of the wire bundle can then spread as an even row in the profile's longitudinal direction, even though the profiles are at a distance from each other on the periphery of the brush.

At least in the case of the second end of the support part, the cross-sectional shape is preferably one of the following: a rectangle, ellipse, or oval. All these shapes permit the brush wires to spread in the transverse direction of the brush cas sette, so that the wire bundles can be place more densely in the brush cassette.

The support part preferably also includes a collar attached to the second end of the support part, in order to maintain the support part's cross-sectional shape. The collar acts to rein force the support part ' s second end, so that the support part ' s cross-sectional shape remains as desired.

At least in the case of its second end, the support part pref erably has a cross-sectional shape that is, in the first di rection, 1.1 - 4-times, preferably 1.2 - 2-times, relative to the second direction perpendicular to the first direction.

The diameter of the first end of the support part is preferably 15 - 30 mm. A sufficient number of wires can then be placed in the support part and the first end can be attached to an ordi nary profile, provided the support part is implemented with the aid of a bushing separate from the profile.

The distance between the first and second ends of the support part can be 20 - 100 mm, preferably 30 - 60 mm. The support part will then support the wires for a sufficient distance, but, on the other hand, will be sufficiently low to allow a large wear margin in the wires of the wire bundles.

The dimension of the cross-section of the support part's second end in the first direction can be 25 - 80 mm, preferably 35 - 60 mm. Thus the individual wires of the wire bundle at the second end of the bushing will spread over a sufficiently wide area .

The cross-sectional dimension of the support part's second end in the second direction can be 15 - 30 mm. Thus the wire bundles can be tightly against each in the profile, creating a dense brush . According to one embodiment, the conduit-like support part can comprise openings to lighten it, or can be mesh-like. Its struc ture will then be lighter.

The wire bundles are preferably in a perpendicular attitude to the profile's longitudinal direction, i.e. the wire bundles are in a perpendicular attitude and do not tilt in the profile's longitudinal direction. The wire bundles then wear essentially evenly at their ends.

The length of a wire bundle can be such that the wire bundle's second end is at a distance of 200 - 350 mm from the surface of the brush's rotation shaft.

According to a first embodiment, each support part is formed in a separate bushing form the brush cassette. The profiles can then be made as pieces separate from the support part and the bushings can, in turn, be set is separate profiles.

The brush cassette's wire bundles are preferably folded in two, thus forming a fold at their first end, the imaginary axis of rotation of which fold, around which the fold is made, is according to the first direction of the cross-section of the second end of the wire bundle, and the brush cassette includes, in addition, a locking wire fitted through the profile between the wire bundle's fold, to lock the wire bundles in the correct attitude in the brush cassette. Thus it can be ensured that the wire bundle cannot turn in such a way that the longer first direction of the second end of the wire bundle turns in the longitudinal direction of the profile. In this context, the term the first end of the wire bundle refers to that portion of the brush wires that is attached to the profile and the term the second end refers, in turn to the free end, which is in contact with the surface being swept. The brush cassettes are preferably set peripherally to form a brush, in which the brush wires are oriented radially outwards.

The support part's first end can be called the attachment end and the second end called the support end.

The wire bundle's first end can be called the bound end and the second end called the free end.

The direction between the first and second ends of the support part is preferably in the brush's radial direction.

The support part preferably grows evenly between the first and second ends. Such a support part is simple to make.

Each bushing can include a cup-like attachment part to attach the wire bundle to the brush cassette, which attachment part is opened at one end, and the conduit-like support part is arranged to attach to the first end of the attachment part, which support part widens away from the attachment part to permit the spreading of the wire bundle's brush wires, the cross-section of the support part's second end being, in the second direction, essentially the size of the attachment part's diameter. It is considerably easier to fit the brush wires into separate bushings than into fixed bushings formed in connection with the profile.

The brush cassette can further include locking means fitted between the bushing and the profile, to lock the bushing in the selected attitude in the profile, which locking means include threads formed in the outer surface belonging to the attachment part and counter-threads formed in the inner surface of the recess belonging to the profile. With the aid of such locking means, the support part's orientation can be ensured by arrang ing the threads so that the support part's attitude is as desired at the end of the threads.

Alternatively the locking means can be formed as a tight fit between the profile's recess and the bushing's attachment part, i.e. friction locking, in which friction locks the bushing to the recess in the correct attitude. In this context, the term a tight fit refers to the tolerance between the recess and the attachment part as being less than 0.2 mm.

According to a second embodiment, the support part is integrated as a fixed part of the profile. A separate bushing is then not needed, but on the other hand the installation of the wires can be more difficult than when using separate bushings. The inte gration of the support part as part of the profile can be implemented, for example, by machining, if the production tech nology permits this.

The purpose of the bushing according to the invention can be achieved by a bushing for the brush cassette of a sweeper, which includes a cup-like attachment part for attaching a wire bundle to a brush cassette, which attachment part is open at one end, and a conduit-like support part comprising a first end for attaching the support part to the attachment part, and a second end. The support part widens away from the attachment part to permit the spreading of the wire bundle's brush wires and at least in the case of the second end larger in the first direction of the shape of the cross-section than is in the second direction perpendicular to the first direction to widen the wire bundle's brush wires in the first direction and narrow it in the second direction, the cross-section of the support part's second end being essentially the size of the attachment part's diameter. In this context, the term cross-section refers to the cross-section relative to the longitudinal direction between the first and second ends.

In other words, at least in the case of the cross-section of the second end, the support part has a flattened shape in the direction of the profile of ±45° to spread the wire bundle's brush wires in the selected direction and to narrow it perpen dicularly to the selected direction.

The bushing according to the invention requires less space in the longitudinal direction of the brush cassette and through that using a brush socket according to the invention the bush ings can be set more densely over a shorter distance, so that there can be more wire bundles and individual brush wires in a brush cassette. In addition, the bushing's "flattened" shape spreads the brush wires laterally over a broader area, when the brush wires of the cassettes placed adjacently lie tightly together. This achieves a greater sweeping effect and wear resistance for the brush.

The bushings in the brush cassette are preferably placed in such a way that the first direction is transverse to the pro file's longitudinal direction and the second direction is the profile's longitudinal direction.

The bushing preferably includes a limiter protrusion arranged between the open end of the attachment part and the first end of the support part to limit sinking of the attachment part on the brush cassette. At the same time, the limiter protrusion also reinforces the bushing, so that it retains better the desired shape of its cross-section.

The bushings are preferably set in the brush cassette in such a way that the first direction is transverse to the profile's longitudinal direction, and the second direction is the pro file's longitudinal direction. Thus, the space taken up by an individual wire bundle diminishes, whereas it grows in the transverse direction, permitting the use of a greater number of wire bundles in the cassette.

The brush wires are preferably of metal or plastic or a corre sponding composite. These are the most commonly used raw mate rials in the case of brush wires.

The bushings in the profile preferably touch each other or are at a distance of at most 10 mm from each other, so that the unused space in the profile is minimized.

The material thickness of the bushing can be 0.5 - 5 mm, 1.5 - 3.0 mm .

The profile preferably includes recesses for placing the wire bundles into or through the profile and locking wires placed longitudinally inside the profile to lock the wire bundles into the profile. The locking of the wire bundles is formed reliably with the aid of the locking wires.

In this context a recess can be a cavity or drill-hole formed in the profile, but the term recess can also refer to an opening extending through the profile.

The diameters of the recesses can be as great as the diameters of the attachment parts belonging to the bushings, in order to form a tight locking.

The bushing is preferably a separate part from the profile. Thus the bushing can be made separately and suitably for its purpose . According to one embodiment, an individual bushing can also include more than one support part, attachment part, and a wire bundle fitted to them. In other words, the bushing can be formed by, for example 2 - 6 support parts attached to each other at the sides, each of which is attached by its first end to an attachment part, one wire bundle being fitted inside each of which support parts.

The bushing is preferably made from an elastic material, thus permitting a temporary deformation of the bushing while attach ing the wire bundle to the bushing. The bushing can then tem porarily deform, for example in the case of its second end, into a completely circular cross-section when installing the wire bundle into the bushing, but then return, in the case of the second end, to a cross-section in which the diameter in the first direction is greater than in the second direction.

The elastic material can be plastic, rubber, or a combination of these, or some other substance suitable for the purpose.

In the brush cassette according to the invention, the term brush rail can also be used for the profile and brush socket, adapter, or cup for the bushing.

When using the brush cassette according to the invention, the number of wire bundles in contact at any particular moment with the surface being swept can be increased considerably, as more wire bundles can be fitted into the brush cassette with the aid of their flattening. 30 % more brush-wire material can be placed in the brush cassette according to the invention than in a brush cassette according to the prior art, as a result of which the service life of a brush according to the invention is about 30 % longer than that of a brush according to the prior art. In addition, the brush cassette according to the invention achieves a better sweeping result than brush cassettes of the prior art, both when new and when worn, because the wire bundles are located closely together and form a nearly or completely unified brush surface, both when new and when worn.

In the following, the invention is described in detail with reference to the accompanying drawings showing some embodiments of the invention, in which

Figure la shows an axonometric view of a brush cassette according to the prior art,

Figure lb shows an axonometric view of a brush cassette according to a first embodiment of the inven tion,

Figure 2 shows an axonometric view of a brush cassette according to the invention, as part of a brush,

Figure 3a shows a view from the end of the brush of a brush cassette according to the prior art, as part of a brush,

Figure 3b shows a view from the end of the brush of a brush cassette according to a first embodiment of the invention, as part of a brush,

Figure 3c shows an enlargement of Figure 3b,

Figure 3d shows the locking means according to one embod iment ,

Figure 4a shows a profile according to the prior art and the bushing attached to it, seen from the side,

Figure 4b shows the bushings according to the invention attached to a profile, seen from the side,

Figure 5a shows axonometrically a profile according to the prior art and the bushings attached to it, with out wire bundles, Figure 5b shows axonometrically bushings according to a first embodiment of the invention attached to a profile, without wire bundles,

Figure 6a shows axonometrically a bushing according to the prior art, shown detached,

Figure 6b shows axonometrically a bushing according to the invention, shown detached,

Figure 7a shows a top view of a profile according to the prior art and the bushings attached to it, shown without wire bundles,

Figure 7b shows a top view of bushings according to a first embodiment of the invention attached to a profile, shown without wire bundles.

In the figures, the following components are referred to using the following reference numbers:

10 brush cassette

10' brush cassette of the prior art

11 brush

12 profile

14 bushing

14' bushing of the prior art

16 front side of the profile

19 first direction

20 individual brush wire

21 second direction

22 wire bundle

24 wire bundle's first end

26 wire bundle's second end

28 bushing's attachment part

30 profile recess

34 profile locking counter-parts

36 brush body

38 brush cassettes' locking rows 42 locking wire

44 end of attachment part

46 limiter protrusion

48 support part

50 support part's first end

52 support part ' s second end

54 collar

56 locking means

58 outer surface of bushing's attachment part

60 threads

62 counter-threads

64 inner surface of recess

Figures la, 3a, 4a, 5a, 6a, and 7a shows brush cassettes 10' and bushings 14' according to the prior art, in which wire bundles 22 are attached to the profile 12 with the aid of bushings 14' according to the prior art. As can be seen from Figure 7a, the bushings 14' have a circular cross-section in the case of the second end 52 of their support parts 48, thus restricting the number of bushings in the profile 12. Thus also the wire bundles 22 attached to the bushings 14' of Figure 3a lie in such a way that the second end of the wire bundles 22 has a cross-section with a circular shape, which restricts the number of wire bundles 22 attached in the longitudinal direc tion of an individual profile 12.

Figure lb shows a brush cassette 10 according to the invention, which includes an elongated profile 12, several bushings 14 arranged on the profile 12 consecutively on one front side 16 in the profile's 12 longitudinal direction, and wire bundles 22 consisting of several individual brush wires 20 for sweep ing. The profile 12 can be, for example, a honeycomb structure moulded from polypropylene or polyethylene or cast from alu minium, in which there can be recess 30, more clearly seen in Figure 3c, for feeding through the first ends 24 of the wire bundles 22. The profile 12 is preferably an elongated structure, with a length of, for example, 0.2 - 2 m and a width of 5 - 10 cm. Figures la - 7b show the wire bundles 22 as pieces with the shape of a cone or flattened cone, but it should be understood that each wire bundles 22 is formed of a large number of indi vidual metal brush wires 20, which are shown in Figure 3c. The brush wires 20 are bundles together at the first end 24 of the wire bundle with the aid of a bushing 14, the second end 26 of the wire bundle 22 being free, so that the individual brush wires 20 are able to disperse over a wide area, which causes the wire bundle's 22 conical shape. The brush wires are pref erably of galvanized steel wire, polypropylene or other plastic fibre or some other similar material suitable for the purpose.

In a first embodiment of the brush cassette 10 according to the invention, the brush cassette 10 includes a bushing, which in turn includes an attachment part 28 and a support part 48, according to Figure 6b. The attachment part 28 is a cup-like structure, to which the wire bundle 22 is attached, for example according to Figure 3c. The attachment part 28 is open at one end 44, and it is to this open end 44 that the conduit-like support part 48 is attached. The attachment part can also have an opening at the other end, to facilitate manufacture. The support part 48 comprises a first end 50 and a second end 52, from which first end 50 the support part 48 attaches to the attachment part 28. The support part 48 widens away from the attachment part 28, in order to permit the spreading of the brush wires 20 of the wire bundles 22. In addition, the support part 48 has a cross-sectional shape at least in the case of its second end 52 that is greater in the first direction 19 than in the second direction 21 that is perpendicular to the first direction 19, in order to spread the wire bundle's 22 brush wires 20 in the first direction 19 and to narrow them in the second direction 21. The cross-section of the support part's 48 second end 52 is in the second direction 21 essentially the size of the diameter of the limiter protrusion 46. In other words, the support part 48 is, from the side, in the shape of a flattened cone.

In the operating position of the brush cassettes according to the invention, their shorter width than that of support parts of the prior art permits the use of a considerably greater number of wire bundles 22 in a brush cassette 10 according to the invention than in a brush cassette according to the prior art, in which all the wire bundles are round in shape and consecutive in the same row. For example, in an 830-mm long brush cassette according to the invention there can be 24 wire bundles, whereas in a brush cassette according to the prior art there can be 19 or 20. This means that the cleaning surface area of the wire bundles increases by at least 20 %. According to one embodiment, in a brush according to the invention the wire bundles can be, in a wider profile than profiles of the prior art, in two adjacent alternating rows, in such a way that the consecutive wire bundles alternate in adjacent rows.

Figure 2 shows a brush cassette 10 according to the invention at an operating site, i.e. as part of a brush 11. In the brush 11 the brush cassettes 10 are attached next to each other on the periphery of the body 36 of the brush's 11 round cross- section. The body 36 includes locking grooves 38 for the brush cassettes 10, which are arranged to correspond to the outer shape of the brush cassettes' 10 profile 12, to achieve shape locking. The locking is preferably shape-locking in such a way that it prevents the brush cassettes 10 from moving radially in the brush 11, but permits movement of the brush cassettes' 10 locking in the longitudinal direction of the brush's 11 body 36. Figures 3a - 3c also show the attachment of the brush cassettes 10 to the brush's 11 body 36. The brush cassette's 10 profile 12 preferably includes locking counter-parts 34 formed longi tudinally on the sides of the profile 12, which correspond in shape to the inner surface of the locking grooves 38 of the brush's 11 body 36. The profiles' locking counter-parts and the body's locking grooves form interlocking means, in which the profiles' locking counter-parts are male tongues and the body's locking grooves are in turn female grooves.

According to Figure 6b, the bushing 14 according to the inven tion has two parts, i.e. the bushing's 14 attachment part 28 and the bushing's 14 support part 48, i.e. its widening. The attachment part 28 is intended to press around the individual brush wires of the wire bundle's 22 first end 24 locking the brush wires into the wire bundle 22. The attachment part 28 can also include a casing structure surrounding the wire bundle's 22 first end, which facilitates pushing the wire bundle 22 into the recess 30 of Figure 3c' s profile 12. The casing structure and bushing can be, for example, of plastic or rubber or a plastic-rubber composition or other similar frost-resistant plastic. The support part 48 in turn permits a gap between the brush wires, which allows the individual brush wires to bend according to the shapes of the surface being swept, which would not be possible if the brush wires were bundled tightly together also at the wire bundle's second end. According to Figure 3c, the profile 12 can include recesses 30, through which the wire bundles' 22 first ends 24 run when the bushings' 14 attachment means are set on top of the profile 12.

The bushing 14 also preferably includes a limiter protrusion 46 and a collar 54, according to Figure 6b. The limiter pro trusion 46 is located annularly between the attachment part 28 and the support part 48. The limiter protrusion's 46 task is to act as a reinforcement between the attachment part 28 and the support part 48 and at the same time to limit the attachment part's sinking into the profile.

According to Figure 3c, the diameter of the profile's 12 recess 30 is preferably the same as the diameter of the bushing's 14 attachment part 28. The first end 24 of the wire bundle 22 pushed folded twice into the recess 30 then lies tightly in the profile 12 and can be locked using a locking wire 42 inside the loop of the wire bundle's first end. In practice, the locking wire can be a thin metal bar running in the profile's longitu dinal direction. The wire bundles are preferably pushed mechan ically into the recesses when making the brush cassettes, so that the recess can be so tight that friction locking is ex tremely powerful. Figure 3c shows more clearly the hollow hon eycomb structure of the profile 12, which is intended to lighten the construction of the profiles and reduce manufacturing costs .

According to a second embodiment of the brush cassette accord ing to the invention, the support part can also be integrated as part of the profile. A recess can then be formed in the profile and a support part in the profile's front side for the wire bundle, which is attached by its first end in the recess to the profile. In such a second embodiment the brush cassette can be implemented without separate bushings .

According to Figure 3d, the bushing 14 can be locked to the desired attitude in the profile 12 with the aid of locking means 56. In Figure 3e the locking means 56 are formed by creating threads 60 in the outer surface 58 belonging to the bushing's 14 attachment part 28, and correspondingly counter threads 62 on the inner surface 64 of the recess 30 belonging to the profile 12. By means of the correct dimensioning of the threads, when the bushing 14 is rotated to the end of the threads 60 the support part 48 will lie at the correct selected direction relative to the profile 12.

According to a third embodiment, the profiles can be so high in the direction of the brush's radius that the support part too is formed as a recess in the profile. The recesses can then be larger in their cross-sectional shape in the first direction than in the second direction perpendicular to the first direc tion, to spread the wire bundles in the first direction and narrow them in the second direction.