Tobacco – Cigar or cigarette making – Molding or forming
Reexamination Certificate
2000-03-03
2001-11-27
Silverman, Stanley S. (Department: 1731)
Tobacco
Cigar or cigarette making
Molding or forming
C131S286000, C131S027100, C131S057500, C131S058000, C131S084100, C131S084200, C131S064100, C131S064200
Reexamination Certificate
active
06321756
ABSTRACT:
BACKGROUND OF THE INVENTION
The invention relates to a device for assembling a continuous strand of tobacco, including a suction strand conveyor belt which is operationally connected with a suction chamber along an assembly track and which is conducted around a contact wheel that revolves along with the suction strand conveyor belt in the strand inlet area of a shaping arrangement that forms the strand of tobacco into a wrapped strand of cigarettes.
Individual and loosened tobacco fibers usually are sprinkled on a strand conveyor in the shape of an endless conveyor belt revolving in a tobacco channel to form a fiber strand for producing a strand of cigarettes. The strand is continuously transported out of the area of the strand formation and evened out before it is deposited on a strip of wrapping material, for example a strip of cigarette paper, which is moved into a shaping arrangement by means of a revolving shaping belt. The strip of wrapping material enters the inlet area of the shaping arrangement still flat and then is molded into a U-shape around the fiber strand during its passage through the shaping arrangement before it is placed completely around the strand and is closed around the strand, as a rule by gluing, along an overlapping seam to form a cylindrical wrapping.
The suction strand conveyor belt usually comprises an air-permeable textile tape on which tobacco particles can be caught and released again at another location. Because of the applied underpressure and/or because of the mechanical pressure in the course of the compression of the fiber strand, the correct transfer of all particles in the strand to the shaping arrangement is prevented. To assure that all particles in the strand, even those which have become stuck to the strand conveyor, are transferred to the shaping arrangement, the latter has a device for stripping off tobacco particles, a so-called scraper, at its inlet end. The scraper consists of a base body and has a scraper edge, which is positioned closely near the surface of the suction strand conveyor belt and scrapes the tobacco particles of the strand away from the belt. The transfer zone of the tobacco strand in which the fiber strand is transferred from the upper suction strand conveyor belt onto the lower cigarette paper strip, conveyed by the shaping belt into the shaper, should be made as short as possible, or respectively should extend as closely as possible next to the shaping belt.
To this end, good results have been achieved with the use of a contact wheel for reversing the suction strand conveyor belt. The contact wheel, which should be as small as possible, creates large centrifugal forces for the better removal of the tobacco strand and permits an optimal placement and design of a scraper assigned to the suction strand conveyor belt. However, a relatively tightly designed belt reversal is extremely sensitive to tobacco dust that is inevitably generated in this area. The tobacco dust acts destructively on the bearing of the contact wheel and is deposited on the circumferential surface of the wheel, so that the suction strand conveyor belt is lifted off and can be destroyed by the scraper.
An attempt to remove dust deposits from the circumferential surface of the contact wheel by placing the scraper against it has not lead to satisfactory results.
SUMMARY OF THE INVENTION
It is an object of the invention to increase the functional dependability of such a contact wheel as used for reversal of the suction strand conveyor belt, and thus optimize its operation in respect to improved strand formation, as well as to increase its service life.
The above and other objects are accomplished in accordance with the invention, wherein in the context of a device for assembling a continuous strand of tobacco as first describe above, the contact wheel is delimited by an air channel in a belt free area of a circumferential section thereof, and the air channel has a flow connection with an interior bearing space of the contact wheel, and another flow connection with the suction chamber.
As a result of the arrangement according to the invention, all inner and outer dust-catching surfaces of the contact wheel are evenly cleaned due to a permanently acting suction draft. In accordance with a further development, the inner surfaces are best reached by the suction draft in that the flow connection with the inner bearing space of the contact wheel is provided by air slits opening on both sides at the circumferential edge of the contact wheel, which are suitably designed in the shape of at least eight radial edge slits.
Shortly before turning around the contact wheel, the suction strand conveyor belt is usually guided along a fixed thrust travel block which, in accordance with a further development, is used to form the air channel by provision of a recess in the thrust travel block guiding the suction strand conveyor.
In accordance with a further development, the efficiency of the air channel is optimized in that it is laterally bordered by lateral walls, which are designed as knife strips and have openings which connect the air channel with the atmosphere.
Even more effective dust catching and dust aspiration is achieved in accordance with another aspect of the invention wherein the thrust travel block is provided underneath the openings of the lateral walls terminating in the air channel with a scraper-like particle retaining wedge, which engages a nip formed between the lower circumferential section of the contact wheel and the suction strand conveyor belt.
In accordance with a further aspect of the invention, a dust removal zone is achieved in that the air channel, which essentially runs concentrically in relation to the contact wheel, extends between the lower retaining wedge of the thrust travel block and an upper scraper, which is connected with the thrust travel block and placed against the contact wheel.
Dust removal from the inner bearing space of the contact wheel is made easier yet in that the front faces of the contact wheel have openings.
The advantage achieved by the invention lies in that, because of the permanent dust removal, or respectively freedom from dust, of the particularly sensitive functional areas, in particular of the bearings and the strand conveyor belt guide surface of the contact wheel, the operational dependability of the latter is maintained over a long time under full load conditions and, along with this, a dependable strand conveyor belt guidance and therefore an increase of the service life of the belt is also assured.
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Hauni Maschinenbau AG
Kinberg Robert
Lopez Carlos
Silverman Stanley S.
Venable
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