The object of the application is a guide jacket for filter segments for the apparatus for feeding sets of filter segments of the tobacco industry.

In machines manufacturing multi-segment filters used in cigarettes, there is a need of feeding multiple different filter segments from multiple feeding apparatuses. Among known segment feeding apparatuses are apparatuses for feeding sets of filter segments, where one set of segments is formed by cutting one filter rod conveyed on a drum conveyor using a cutting head provided with circular knives. Known segment feeders are provided with arched rod guides the function of which is to hold and guide the rods along an arched guiding path, before cutting, during cutting of the rods as well as to guide cut filter segments, whereas as many guides are used as many segments a filter segment is cut into. The guides of this type are known from GB 1 029 127 A and GB 1 043 706 A.

The GB 1 029 127 A publication disclosed multiple situated parallel to each other segment guides, whereas circular knives together with the elements fastening the knives are situated in spaces between adjoining guides, and the width of a guide in the embodiment corresponds at most to a half of the segments' length.

Similar guides with a similar proportion of the guide length to the segment length was disclosed in the GB 1 043 706 A publication.

They are fastened and adjusted independently from each other, what is time-consuming, and in addition creates the risk that differences in the adjustment of guides for particular segments of the set of segments may exist. Furthermore, the length of the filter segments is several times greater than the width of the guide, which causes an increase of unit pressures on the lateral segment surface and can lead to segment damage.

The problem solved by the invention is to avoid the abovementioned drawbacks, in particular to eliminate the unit pressures on lateral surfaces of a filter rod segment. The object of the invention is also to shorten the time of replacement of the guiding elements and to simplify the system assembly, adjustment and maintenance.

The object of the invention is a jacket guiding filter rods for an apparatus for feeding filter segments provided with a drum conveyor having flutes for crosswise transferring filter rods and a cutting head having a plurality of circular knives mounted in a housing of the head, characterized in that it has a uniform principally cylindrical surface guiding filter rods and, in addition, having a plurality of slots for circular knives of the cutting head.

Preferably a jacket according to the invention is characterized in that the outer surface of the jacket has depressions formed for the elements fastening the circular knives.

Preferably a jacket according to the invention is characterized in that the depressions formed are cylindrical.

Preferably a jacket according to the invention is characterized in that in the outer surface of the jacket the depressions for spacers between the circular knives are formed.

Preferably a jacket according to the invention is characterized in that the depressions formed are as cylindrical.

A guiding jacket according to the invention replacing multiple single guides permits shortening the assembly time of the apparatus for feeding sets of segments. A filter rod, and then cut segments are guided at their maximum possible length because the sections in the jacket have a width only slightly greater than the thickness of the knives what results in that the unit pressures on the surface of the rods and the segments are reduced, which is very significant for the quality of fed filter segments, especially when rods made of a hard, brittle material are cut. The rigid construction of the jacket ensures that during the operation of the apparatus no risk of its deformation or damage exists, e.g. in case of filter rod jamming.

A guiding jacket according to the invention shortens the time of replacement of the guiding elements and simplifies the system assembly, adjustment and maintenance. The object of the invention is shown in a preferred embodiment in a drawing in which:

Fig. 1 - shows a view of an apparatus for feeding sets of filter segments,

Fig. 2 - a perspective view of a cutting head with two knife shafts,

Fig. 3 - a perspective view of the cutting head of Fig. 2 with a guiding jacket,

Fig. 3a - a perspective view of the guiding jacket of Fig. 3,

Fig. 4 - a knife unit and a cross-section of a guiding jacket,

Fig. 5 - a knife unit and a cross-section of guides known from the state of the art,

Fig. 6 - a guiding jacket in a view from the side of the drum conveyor,

Fig. 7 - a guiding jacket in a view from the side of the cutting head.

Fig. 1 shows an apparatus for feeding sets of filter segments provided with a hopper 1 for filter rods 2 fastened to a main plate 3. Beneath the hopper 1 there is a drum conveyor 4 provided with a plurality of flutes 5 on the circumference into which the filter rods 2 from the hopper 1 are inserted and in which the said rods are conveyed. The filter rods 2 are conveyed crosswise to their axes in accordance with the direction of rotation of the drum conveyor marked with an arrow, along an arched guiding path 12 situated between the drum conveyor 4 and an inner principally cylindrical guiding surface 14 of a guiding jacket 13. During the movement along the guiding path 12 the filter rods 2 are cut into segments by circular knives 6 attached to knife shafts 7 mounted in a housing 8 of a cutting head 9, whereas during the operation the circular knives 6 are pushed into slots formed in the jacket 13 and into peripheral grooves formed in the drum conveyor 4. Depending on the quantity of filter segments into which the filter rods 2 are cut, the cutting head 9 is provided with one of more sets of circular knives 6 attached to the knife shafts 7. Hereinafter, the knife shaft 7 with knives 6, distance sleeves, distance pieces and bearings will be referred to as a knife unit 10. The rotation axis X of the knife unit 10 is situated at the outer surface 15 of the jacket 13 in order to make pushing the circular knife 6 above the guiding surface 14 and consequently cutting of a filter rod 2 possible. A set of filter segments 11 formed by cutting a filter rod 2 is picked up usually in the lowest position of the flute 5 at the drum conveyor 4.

Fig. 2 shows a cutting head 9 provided with a plurality of knives 6 attached to two knife units 10. The unit 10 is disposed in a housing 8 in positioning pockets 18 and 19. For reasons of simplification, the connecting elements fastening the knife unit 10 to the housing 8 have been omitted in the drawing. The head 9 shown in Fig. 2 can be provided with one more knife unit 10. Fig. 3 shows a cutting head presented in Fig. 2, whereas the knives 6 of the units 10 are pushed into slots 20 of a guiding jacket 13. For reasons of simplification the fastening elements of the guiding jacket 13 have not been shown. The guiding jacket 13 itself having the slots 20 has been shown in Fig. 3a.

Fig. 4 shows a knife unit 10 with knives 6 which are attached by means of fastening elements 21 situated between spacers 22. A jacket 13 in a cross-section which plane passes through the rotation axis X of the knife unit 10 is also shown. In an outer surface 15 of the jacket 13 depressions 23 and 24 are formed, the purpose of which is to make pushing of the knife unit 10 close to the outer surface 15 of the jacket 13 possible so that the blades of the circular knives 6 protrude at an appropriate distance beyond an inner guiding surface 14 in order to make cutting of filter rods 2 possible. The depression 23 is adjusted to the shape and the dimensions of spacers 22, whereas the depression 24 is adjusted to the shape and the dimensions of the fastening elements 21. For comparison, Fig. 5 shows a solution known from the state of the art in which cut segments of a filter rod 2 are guided by separate independent guides 30.

Fig. 6 shows a guiding jacket 13, adapted to the cooperation with two knife units 10, presented from the side of a drum conveyor 4. In the jacket 13, a plurality of longitudinal slots 20 with a width slightly greater than the thickness of a circular knife 6 are formed, where the said width allows inserting the knife 6 into the slot 20. The position of the knife units 10 relative to the guiding jacket 13 is indicated by shown rotation axes X of the said units. Fig. 7 shows the same guiding jacket 13 from the side of a cutting head 9. Depressions 24 corresponding to fastening elements 21 are formed in this embodiment as cylindrical depressions. Similarly, depressions 23 corresponding to spacers 22 are cylindrical. In practice, other shapes of the depressions 23 and 24 are also possible.

A jacket 13 can be also formed as a thin-walled element without depressions for spacers and circular knife fastening elements while maintaining its essential function of guiding filter rods and segments at the greatest possible length of their lateral surface.