Ever since the 1970's, various sweeping machines have employed brush elements of a brush wheel type, which are used for assembling the actual brush of a sweeping machine. However, in sweeping machines used particularly for airport sweeping operations, the use of brushes compiled from brush wheels has diminished over the recent years as so-called cassette brushes have become more and more popular, a particular advantage offered by the latter over the brush wheel system being a convenient and quick installation.

Thus, the brush is assembled simply by inserting the cassette brushes through the end of a machine's brush mounting into the interior thereof and into locking grooves present therein.

For example, US patent 5,383, 245 discloses one cassette brush embodiment of this type, wherein the

bristles of a bristle component are attached in the form of bristle tufts to a brush mounting by means of a plastic sleeve and a locking wire, as shown in front and side views of figs. 3a and 3b.

However, the above type of cassette brush solution is plagued today by quite serious drawbacks. Firstly, the interspace between bristle tufts in a brush compiled therefrom always leaves a streaky sweeping trail as a result of bristles wearing down. Another major drawback is that the number of bristles contributing to sweeping performance is always lower in cassette brushes than e. g. in a brush wheel system, nor is it possible to increase the number of bristles in the above type solution, since the employed plastic sleeve cannot accommodate an abundant number of additional bristles. In principle, the above type solution is unnecessarily complicated also in terms of its construction, which is why its assembly requires a plurality of separate operations.

On the other hand, Finnish utility model No. 138 has earlier disclosed a brush element which, although its intended application is other than that of a cassette brush of the above described type, is nevertheless consistent with the present invention in the sense that the cassette brush has its stem component partially manufactured in a bonding material possessing adhesive and bonding qualities, such as a foamed elastomer material, for example polyurethane or resin. In this conjunction, a mounting preform for the brush element, which is manufactured for example by extrusion or some other similar manufacturing process, is first provided with a pattern of holes, followed by inserting bent or folded bristles in the holes. This

is followed by sealing the ends of the mounting preform, the injection of a bonding material into the interior of the stem component being performed at either one or both ends.

A downside in this type of solution is first of all the necessity of using a traditional bristle bunch construction. Thus, on the other hand, when making the bristle bunches from double-folded bristles, it is indeed necessary, in order to achieve a sufficient reliability, to employ suitable binding elements for binding the bristles together despite the presence of a chemically solidifiable bonding material. In practice, however, this does not provide a capacity to guarantee a sufficiently effective miscibility for the bonding material amongst and within the bristle bunches, which is why the bristle bunches may lose some of the bristles as a result of being pulled at one of the bifurcations thereof or, for example, as a result of bristles breaking during use.

Thus, the solution according to the above-cited utility model is not, as such, applicable in sweeping machines used particularly e. g. for airport sweeping, which is a service that requires particularly high operating reliability in the sense that any unintentional loss of bristles from the brush of a sweeping machine cannot be accepted.

It is an object of the present invention to provide a decisive improvement regarding the above problems and, thus, to raise essentially the existing state of the art. In order to fulfil this object, a method of the. invention is principally characterized in that the cassette brush is manufactured by placing a bristle component, provided with an array of bristles

extending continuously in the longitudinal direction, in a casting mould supplied with forming plastics in a fluid state, which, upon solidifying to a solid state, bonds the bristle component to the stem component in such a way that a coupling mechanism present in the stem component is formed concurrently with casting by means of an expansion member, present in the casting mould and having a thickness which, in a cross-sectional sense, exceeds a basic wall thickness of the complementary surface of the stem component.

First of all, it should be appreciated that the most important benefit gained by a method of the invention is the simplicity provided thereby in manufacturing a cassette brush. On the other hand, by casting the stem component of a cassette brush from forming plastics, it is possible to produce an extremely integrated cassette brush, which under no circumstances shall unintentionally lose bristles, regardless of whether the bristle component is provided with plastic and/or metallic bristles; it is indeed the secure and permanent attachment of bristles which is a particularly essential requirement, especially in airport sweeping machines or the like. By virtue of a method of the invention, it is also possible to produce brush assemblies remarkably more homogeneous than those available at present, the cassette brushes used therein having a capacity of operating at high sweeping performance for a significantly longer time than what is achieved by the current counterparts thereof.

Preferred applications for a method of the invention are set forth in the dependent claims directed thereto.

The invention relates also to a cassette brush, as defined more accurately in the preamble of the independent claim directed thereto, the essentially characterizing features thereof being set forth in the characterizing section of the same claim.

The most important benefits gained by a cassette brush of the invention include particularly the simplicity of its construction and operation, whereby the brush, assembled from a cassette brush construction remarkably simpler than those available at present, has a capability of sustaining an optimal sweeping result for significantly longer than what is achieved with solutions available at present. This is particularly by virtue of the fact that the cassette brush is provided with a lengthwise continuous array of bristles, whereby the mutual distance between individual bristle bunches present in cassette brushes of the above-discussed type, or wearing of the bristles, no longer causes similar problems as the array of bristles in a cassette brush is wearing down.

By virtue of this, on the other hand, as little bristle wire material as possible is left in worn-out and discardable brush cassettes. By virtue of the invention, it is also possible to vary the width of a bristle component included in a cassette brush for further contributing to the service life of a cassette brush, this possibility being non-existent in cassette brushes consisting of bristle tufts assembled by means of plastic sleeves. In addition, the brush, assembled from cassette brushes of the invention, provides a sweeping action which is remarkably more homogeneous than that of current cassette brushes and, furthermore, there is virtually no risk of the sweeping action releasing harmful material e. g. on the runway, since there is a very strong attachment

between the bristle component and the forming plastics constituting the stem component.

Preferred embodiments for a cassette brush of the invention are set forth in the dependent claims directed thereto.

The invention will be described in detail in the following specification while reference is made to the accompanying drawings, in which figs. la and lb depict an operating principle for a method of the invention, and a cassette brush manufactured thereby in front and side views, fig. 2 shows by way of example a brush mounting for a sweeping device, figs. 3a and 3b show, in a front view and in a side view, a traditional cassette brush assembled from bristle tufts by means of plastic sleeves and a locking wire, fig. 4 shows, in a cross-sectional view, one preferred alternative embodiment for a method and cassette brush of the invention, and fig. 5 shows, in a perspective view, a cassette brush manufactured according to the principle depicted in fig. 4.

The invention relates to a method for manufacturing a cassette brush, said cassette brush being intended for making a brush consisting of a plurality of consistent cassette brushes attached to a brush mounting R in a sweeping machine. The cassette brush is first of all assembled from an elongated stem component 1, which carries a coupling mechanism integrated therewith for attaching the cassette brush on quick coupling principle, such as by a snap fit coupling, to the brush mounting R of a sweeping machine, and, on the other hand, from a bristle component 2 carried by the stem component in at least a single file essentially in a longitudinal direction s. The cassette brush has its stem component 1 manufactured at least partially in forming plastics, such as polyurethane or the like.

The cassette brush is manufactured by placing, for example on the principle shown in figs. 1b and 4, the bristle component 2, provided with an array of bristles extending continuously in the longitudinal direction s, in a casting mould V supplied with forming plastics in a fluid state, which, upon solidifying to a solid state, bonds the bristle component 2 to the stem component 1 in such a way that a coupling mechanism 3 present in the stem component is formed concurrently with casting by means of an expansion member L, present in the casting mould V and having a thickness which, in a cross-sectional sense, exceeds a basic wall thickness w of the complementary surface of the stem component 1. Consequently, a cassette brush, provided with the coupling mechanism 3 designed as described above, is attachable in place on quick coupling principle by inserting it through the end of a brushing device, e. g. the brush mounting R as shown in fig. 2, into locking grooves LU present therein.

In a preferred embodiment, the forming plastics comprises a chemically solidifying two-component material, such as e. g. polyurethane, epoxy, resin or the like.

In reference to one preferred implementation regarding a method of the invention, depicted particularly in fig. 4, the stem component 1 includes a shell portion 1111, which is placeable in the casting mould V and filled with forming plastics for anchoring the bristle component 2 by one of its ends firstly at the shell portion and, on the other hand, after solidification of the forming plastics, to the stem component 1; 1', 1"'constituted by the forming plastics.

Furthermore, in a solution alternative or complementary to the above embodiment, the stem component 1 is manufactured in two or more processes, the first process comprising, especially in reference to figs. la and lb, the forming of a rigid elementary mounting 1'for the stem component of a cassette brush, the bristle component 2 having its bristles anchored therein by one end thereof, on top of which is cast, after solidification thereof, a substantially more flexible complementary portion 1"for providing an elastic bracing especially for the bristle roots of the bristle component 2.

In a further preferred embodiment, the bristle component 2 is provided with bristles 2', made at least partially from a plastic-based material, such as polypropylene or the like. In an optional solution, the bristle component 2 is provided with bristles 2", made at least partially from a metal material, such as steel, or else with a combination of the above, as shown e. g. in fig. lb. In view of giving more rigidity

and dimensional stability to the array of bristles, the bristle component 2 is generally provided with crimped bristles, although this is not exhibited in the attached figures. Respectively, especially with regard to the bristle component's plastic bristles, it is preferred that those be manufactured as a continuous bristle component preform by fusing the same together in the preparation stage by the anchoring ends thereof.

The invention relates also to a cassette brush for the above purpose, wherein a coupling mechanism 3, present in a stem component 1 of the cassette brush consisting of a stem component manufactured at least partially in forming plastics, such as polyurethane or the like, and of a bristle component 2, provided with an array of bristles extending continuously in a longitudinal direction s, comprises an enlargement L', formed integrally therewith substantially concurrently with the casting of the stem component 1 and having a thickness which, in a cross-sectional sense, exceeds a basic wall thickness w'of the stem component 1.

In a particularly preferred embodiment for a cassette brush of the invention, especially in reference to the solution shown fig. 4, the stem component 1 includes a shell portion 1111, which is filled with forming plastics for anchoring the bristle component 2 firstly by the shell portion and, on the other hand, after solidification of the forming plastics, to the stem component 1; 1', 1"'constituted by the forming plastics.

In a further preferred embodiment, the shell portion 1"'is provided integrally with support elements tv for bracing the bristle component 2 at its root by

limiting the freedom of movement of bristles especially in a lateral direction p. In a cassette brush as shown in figs. 4 and 5, the support elements are constituted by a collar member K, included in the shell portion 1"'and having a bearing surface Ktp bowing out symmetrically on both sides for limiting a lateral movement allowed for the bristles of the bristle component 2. Naturally, the above-described solution can also be utilized in other ways, for example in such a way that the above type of collar member is designed as a separate element, which is anchored by appropriate means for example to the brush mounting R of a sweeping device. On the other hand, it is also possible to employ a collar member which is just unilateral, although a general objective in the present context is to strive for solutions as homogeneous and symmetrical as possible.

In reference to the above, in a solution alternative or complementary thereto, the stem component 1 of a cassette brush, which is manufactured at least partially in a chemically solidifying two-component material, such as e. g. polyurethane, epoxy, resin or the like, comprises a rigid elementary mounting 1', on top of which is provided integrally, as shown in figs. la and lb, a substantially more flexible complementary portion 1", particularly for bracing elastically the roots of the bristles in the bristle component 2.

In a particularly preferred embodiment, the bristle component 2 is provided, along the edges thereof, with bristles 2'made from a plastic-based material, such as polypropylene or the like, and in its middle section, with bristles 2"made from a metal material, such as steel, which are anchored to the stem component 1 by one end thereof. This type of cassette

brushes are useful for conditions with weather changing constantly and rapidly from freezing to slush, the steel brushes eliminating formations of ice and the plastic bristles removing effectively snow/slush.

The shell portion 1"', included for example in a cassette brush of the type shown in figs. 4 and 5, is preferably manufactured in a suitable plastic material, for example by means of extrusion or pultrusion. This enables, for example, the manufacturing of completely plastic-structured cassette brushes. On the other hand, the material for the discussed shell portion may also comprise extruded aluminium or some other equivalent light metal, which is further provided, if necessary, e. g. with a plastic coating.

It is obvious that the invention is not limited to the embodiments discussed or described above, but it can be varied within the scope of the basic inventive concept according to given demands and operating conditions. Hence, first of all, it is obvious that the configuration of a stem component may be other than what is described above, depending on a current way of coupling the same with the brush mounting of a sweeping machine. In addition, its dimensions and appearance are naturally subject to variations, depending on the dimensions of a presently manufactured cassette brush. Applying the inventive method, it is possible to manufacture a bristle component provided, on the one hand, with arrays of bristles extending discontinuously on the stem component of a cassette brush, or else, e. g. in such a way that the bristle component spirals along the stem component with a gentle helix. Furthermore, as

opposed to what is shown in fig. lb, it is also possible to assemble a bristle component in such a way that, in lateral direction, it carries even a larger number of alternating blocks of plastic and metallic bristles.