FI102663B - Pressure roller assembly for fastener roll of a paper cutter - Google Patents

Description

102663

Press roll unit for paper cutter reel

The invention relates to a printing roller unit for a paper cutter reel, which printing roller unit comprises two adjacent rolls around which a belt arrangement operatively connecting the rolls is rotated, and wherein an electric motor driving the roller unit is disposed within the at least one roller.

Electric motors are generally cooled by blowing air on the surface of the motor or through passages inside the motor with a fan mounted on an electric motor shaft or driven by a separate motor. It is essential to provide a sufficiently high velocity for the air flow adjacent the surface to be cooled.

15 In the case of a press roll unit, the electric motor driving it is an external rotor motor mounted inside the press roll, which is not normally cooled. The roll cover belt arrangement is conventionally made of rubber, whereby heat transfer is inadequate because the rubber belt has poor heat conductivity compared to the steel of the roll material.

The object of the present invention is to eliminate the aforesaid drawback, i.e. to provide sufficient cooling of the surface of the motor itself and of the roll at its location. This object is achieved by the printing unit, which according to the invention is characterized in that at least one opening is provided in the belt arrangement for cooling the electric motor and the surrounding roll.

The invention is thus based on the idea of directly contacting the surface of the rotating roll 30 with the ambient air, which ensures an efficient heat transfer from the roll to the air.

It may be most advantageous to use a solution in which the belt arrangement comprises at least two belts arranged at a selected distance from each other to form at least one cooling opening.

102663 2

The invention will now be explained in more detail by means of a few preferred embodiments with reference to the accompanying drawings, in which Figure 1 shows a conventional printing roller unit, Figure 2 shows a preferred printing roller unit according to the invention, and Figures 3 and 4 show alternative embodiments of the invention.

The conventional printing roller unit 10 for the paper cutter reel assembly shown in Figure 1 comprises two adjacent rolls 1 and 2, which are wrapped around a single rubber belt 3 extending across the entire width of the rolls and covering them completely to drive this roller unit. 4. Alternatively, the printing roller assembly may also be driven by an electric motor provided in a single roller.

The printing roller assembly according to the invention shown in Fig. 2 differs from the conventional solution 20 according to Fig. 1 in that the belt arrangement rotating about the rolls 1 and 2 is divided into two belts 30A and 30B spaced apart so that an open space 5 is left between them. to the electric motor 4 located inside the roller 1, 2. In this case, the heat from the motor 4 to the blade 1, 2, due to the speed difference between the ambient air and the roll 1, 2, is effectively transferred to the air, thereby keeping the temperature of the motor 4 and the roll 1, 2 significantly lower than in the previous embodiment.

In an alternative embodiment of the invention shown in Figure 3, the belt arrangement is further divided into a plurality of separate belts 30N, whereby there are several open spaces 5 between the belts 30N which cool the roller 1, 2 and the motor 4. In this case, the heat possibly applied to the ends of the rolls 1,2 may be discharged more efficiently, thereby further reducing the thermal stresses of the roll unit.

Figure 4, in turn, illustrates another alternative embodiment of the invention having one belt 30 which wraps around rollers 5 1, 2 and extends across their entire width, as in the conventional arrangement of Figure 1, but which is perforated (holes 5 ') at least by an electric motor. 4 to provide a direct connection between the roll surface and the ambient air described above and thereby provide cooling 10.

The reduction of thermal stresses described above increases the durability of both the motor 4 and the rollers 1, 2 as well as the belt arrangement itself and also eliminates the harmful thermal expansion due to the uneven heating of the rolls 1, 2.

The invention has been described above with reference only to some advantageous exemplary embodiments thereof. However, one of ordinary skill in the art can freely construct its structure within the limits set forth in the appended claims.

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Claims (5)

102663 A printing roller unit for a paper cutter reel, comprising two adjacent 5 rolls (1, 2) around which a belt arrangement (3; 30A, 30B; 30N; 30) operatively rotates the rolls, and wherein at least one roller is provided with a roller unit. electric motor (4), characterized in that at least one opening (5) is provided in the belt arrangement (30A, 30B; 30N; 30) for cooling the electric motor (4) and the surrounding roll (1, 2). A printing roller assembly according to claim 1, characterized in that the belt arrangement comprises at least two belts (30A, 30B; 30N) arranged at a selected distance from each other to form at least one cooling opening (5). A printing roller assembly according to claim 1, characterized in that the belt arrangement is formed by a single belt (30) around which a plurality of cooling openings (5) are formed. Printing roller assembly according to Claim 3, characterized in that the cooling openings (5) consist of a hole in the belt. Printing roller assembly 25 according to one of the preceding claims, characterized in that the cooling opening (s) (5) are arranged at least at the drive electric motor (4). •> 5,102,663