EP0707927B1 - Cutting device having a motor - Google Patents

Description

The invention relates to a cutting device for band-shaped materials, which an electromotive drive for driving a slidably mounted Has flat knife and a fixed knife, the slidably mounted Flat knife is laterally stored in a bearing element and that slidable flat knife essentially over its cutting edge attaches to the cutting edge of the fixed knife, so that this results in a three-point bearing of the flat knife can be formed, and that the slidably mounted Flat knife over two essentially symmetrical to the direction of movement of the flat knife running center line arranged drive points can be driven is.

Such a cutting device has been proposed in WO 94/26478 (EP-A 0 693 939), prior art according to Art 54 (3) EPC, and z. B. for cutting paper tapes, such as. B. in printers or Card machines are used.

EP-A 0 519 102 describes a device for cutting off individual cards of continuous card material with a fixed bottom knife and a relative for this purpose longitudinally guided upper knife that from an engine over a Eccentric is known. To be a simple, space-saving and good The upper knife is used to create guidance and storage of the upper knife longitudinal grooves parallel to the direction of movement, into each of which a guide point a bearing roller engages. On each long side of the upper knife attack three such bearing rollers, two of which are on the drive side End of the upper knife on the top and bottom opposite and one Bearing roller is designed as a hold-down device and the upper knife defines the lower knife leads. The upper knife is on both sides of the cutting edge with over these excellent Guide zones formed, which also in the rear end position of the upper knife rest on the lower knife.

From DE-A 40 20 630 is a cutting device for coverings, journal rolls and the like, in which a movable knife on a fixed Knife bar slides past, the movable knife with the drive connected is. For this purpose, the movable knife is mounted on a carrier part. It there are two eccentrically symmetrical support points on which the movable knife rests elastically, with the movable knife in the middle between the support points in the cutting direction and as a three-point bearing is supported.

A cutting device described in DE-OS 35 07 620 works with a fixed cutting edge and a longitudinally movable flat knife, which is stored on a fixed carrier. This creates high Frictional forces that are overcome by the drive of the cutting device have to.

In order to obtain a reliable cutting process, it is known that the flat knife has a V-shaped cutting edge in plan view and seen in section is slightly roof-shaped. Here the flat knife is under tension pressed against the fixed knife, taking the necessary counterforce can be included in side sliding guides. Such a construction has the disadvantage that friction forces in the side guides arise, which are overcome by the drive of the cutting device have to. It is also disadvantageous that the cutting device is subject to high wear. Lubrication in the side guides Sliding knife is only possible to a limited extent because - predominantly when cutting paper-like tapes - the resulting dust on Would set lubricant.

It is also disadvantageous that in known cutting devices often the drive only attaches to a single point on the knife, so asymmetrical tilting forces arise, which are disadvantageous the friction and thus the wear of the cutting device reinforce.

It is therefore an object of the invention to provide a cutting device at the beginning mentioned type in such a way that friction losses are compensated or at least be reduced.

This object is achieved in that the flat knife driving drive part via essentially symmetrically arranged drive levers is connected to the points of attack of the flat knife that the on Flat knife attacking first drive lever at its drive end is connected to the drive and a toothing at its output end has, and that the second drive lever at its drive end another interacting with the toothing of the first output lever Has teeth and at its output end with a pin is connected to the second point of attack of the flat knife.

Advantageous developments of the invention are the subject of Subclaims.

Figur 1

ein erstes Ausführungsbeispiel einer Abschneidevorrichtung in der Draufsicht,

Figur 2

einen Schnitt entlang der Linie G-H der Figur 1,

Figur 3

eine Messerbaugruppe des Ausführungsbeipiels in einer Draufsicht (teilweise geschnitten),

Figur 4

einen Schnitt durch die Figur 3 entlang der Linie E-F,

Figur 5

eine Beispiel einer Abschneidevorrichtung in der Draufsicht, das nicht unter die Ansprüche fällt,

Figur 6

eine Teilansicht gemäß der Figur 5,

und

Figur 7

einen Schnitt durch die Figur 6 entlang der Linie J-K.

Further details and advantages of the invention can be found in exemplary embodiment 1, which is described below with reference to FIGS. 1-4. Show it:

Figure 1

a first embodiment of a cutting device in plan view,

Figure 2

2 shows a section along the line GH in FIG. 1,

Figure 3

a knife assembly of the exemplary embodiment in a plan view (partially cut),

Figure 4

4 shows a section through FIG. 3 along the line EF,

Figure 5

an example of a cutting device in plan view, which does not fall under the claims,

Figure 6

5 shows a partial view according to FIG. 5,

and

Figure 7

a section through Figure 6 along the line JK.

In Figures 1 to 4 is a first embodiment of a cutting device 1, which shows a drive unit accommodated in a housing 2 Flat knife 14, which consists essentially of a drive motor 3 Worm 4 and a worm wheel 5 with a drive pin 6 there. The Drive pin 6 engages in an arranged in the drive end of a connecting rod 8 angular recess 7 a. An output end of the connecting rod 8 is hingedly connected to a drive lever 9 which is mounted on a pin 10 is. A toothing 11 of the drive lever 9 engages in a corresponding toothing 11a one mounted on a pin 10a with the drive lever 9 largely identical another drive lever 9a. As best out of figure 2 can be seen, the two pins 12, 12a engage in corresponding openings 13, 13a of the flat knife 14 and thus form essentially symmetrical to the center line of the flat knife 14 arranged drive points for the flat knife 14 out.

Now the worm wheel driven by the drive motor 3 via the worm 4 5 moves, this rotary movement via the connecting rod 8 on the drive lever 9 transmitted, which thus executes a pivoting movement about the bolt 10. This pivoting movement of the drive lever 9 is via the two toothings 11, 11a transferred to the drive lever 9a, so that with the drive lever 9, 9a up and over the pegs 12, 12a connected flat knives 14 can be moved.

The provided for the cutting device 1 symmetrical drive of the Flat knife 14 over the essentially symmetrically arranged to each other Drive lever 9, 9a has the advantage that in the cutting process in advantageously, asymmetrical tilting forces cannot occur.

The flat knife 14 is - as best seen in FIG. 3 rotated by 90 ° can be seen from Figure 4 - in two laterally arranged notches 21, 21a stored on balls 17-20. This ball bearing of the flat knife 14 in The notches 21, 21a has the advantage of being particularly low-friction Guide. Furthermore, the flat knife 14 of the cutting device 1 slides in the cutting process only with its cutting edge 15 via a with the flat knife 14 cooperating fixed knife 16, so that even in this area a particularly low level of friction is achieved.

In an advantageous manner, the bearing balls 17-20 in the notches 21, 21a fixed in such a way that the flat knife 14 is formed with a pretension is. As a result of the three-point support of the flat knife 14 by means of the side arranged notches 21, 21a with bearing balls 17-20 and the leadership of Flat knife 14 along its cutting edge 15 over the fixed knife 16 is the formed by the flat knife 14 and the fixed knife 16 Knife group arrangement statically stable in an advantageous manner. Moreover is due to the bias of the flat knife 14 in the cutting device 1 ensures an exact system on the fixed knife 16.

The knife can also be stored according to the example of Figures 6 and 7 (claims 3-5).

The cutting device 1 described is also characterized by that in a particularly simple manner both a full cut and can make a partial cut: Through the angular recess 7 in Connecting rod 8 is achieved in an advantageous manner that in one revolution of the worm wheel 5 in a direction of rotation running clockwise in FIG the drive pin 6 in the shallower recess 7 'of the two recesses 7 ', 7 "of the recess 7 engages so that the flat knife 14 then preferably executes the maximum possible stroke, so that the one to be separated Tape is cut off completely.

If the motor 3 is reversed, so that the worm wheel 5 against the aforementioned Direction of rotation rotates, the drive pin 6 engages in the deeper recess 7 "of the recess 7, which causes the stroke of the flat knife 14 becomes correspondingly smaller. Due to the preferably V-shaped cutting edge 15 now the tape to be cut is not cut completely, so that it is possible in a particularly advantageous manner and in a particularly simple manner, too to make a partial cut.

FIGS. 5 to 7 now show an example of a cutting device 100 shown. In this example it is provided that on Housing 2, a geared motor 23 is attached, which via a toothed belt 24th Drive wheels 25 and 25a drives, the drive pins 28, 28a, which engage in the connecting rods 29 and 29a, which in turn are articulated with bolts 10, 10a Levers 30, 30a are connected, which correspond to a flat knife 14 Attack flat knife 32 via connecting bolts 31, 31a. On in this way, it is easily possible for one triggered by the geared motor 23 Rotational movement of the drive wheels 25, 25a in a lifting movement of the lever 30 and 30a and thus the flat knife 32. Optionally, pulleys can also be used 26, 26a can be provided, which the wrap angle of Increase timing belt 24 by a pinion 27 of geared motor 23.

In order to guide the flat knife 32 with as little friction as possible and around one uniform pressure of the flat knife 32 on the cutting edge 37 of the To achieve fixed knife 16 corresponding fixed knife 33 is one with a Stop 38 cooperating guide part 34 (see Figure 7) is provided, which preferably via a slide shoe 35 by means of a spring element 36 sprung on both sides at the level of a cutting edge 37 on the flat knife 32 is. But it is also possible to use the guide part 34 as a self-resilient part to train.

The defined knife guidance that can be achieved thereby between the stop 38, the fixed knife 33 and the guide member 34 advantageously and Assign a defined pressure to the cutting edge 37 'of the flat knife 32 the cutting edge 37 of the fixed knife 32. Such a measure has the The advantage that a self-sharpening effect is achieved.

The advantage of this cutting device of the example in FIGS. 5 to 7 is in the fact that these are particularly easy on different large working widths is variable, since it is essentially only necessary for this to be the length of the To adjust timing belt 24 accordingly.

In summary, it should be noted that the described embodiments the cutting device 1,100 result in a flat design of the same, which is advantageous for versatile use Printers and with automatic cutting processes enabled. As a result the smooth storage of the flat knife 16 or 32 by means of the bearing balls 17-20 or the parts 34, 38 are the friction losses significantly minimized, so that the power consumption of the described Cutting device 1,100 is reduced. This is particularly advantageous on the heat development of the device 1,100.

Claims (6)

1. Cutting device for strip stock which is provided with an electric-motor drive (3) for driving a displaceably supported flat blade (14) and a stationary blade (16; 33), wherein the displaceably supported flat blade (14) is laterally supported on bearing elements (17-20, 21, 21 a), one on each side, and the displaceably supported flat blade (14) contacts substantially only with its cutting edge (15) the cutting edge (15') of the stationary blade (16), so that a three-point support for the flat blade (14) is obtainable, and in this way the displaceably supported flat blade (14; 32) is drivable in two points (13, 13a; 31, 31a) which are substantially located symmetrically with respect to their center line, wherein the drive assembly (3, 4, 5, 6, 7, 8) which drives the flat blade (14) via substantially symmetrically arranged driving levers (9, 9a) is connected with engaging points (13, 13a) of the flat blade (14), the first driving lever (9) attached the flat blade (14) is connected with the drive (3, 4, 5, 6, 7, 8) via its end directed towards the drive, and has at its end opposite to the drive an interlocking (11), and the second driving lever (9a) at its end towards the drive has a further interlocking (11a) which works together with the interlocking (11) of the first driving lever (9) and is connected on its end opposite to the drive with the second engaging point (13a) of the flat blade (14) by a pin (12a).
2. Cutting device according to claim 1, characterized in that the lateral bearing element for flat blade (14) is composed of a guide slot (21, 21a) with roller balls (17-20).
3. Cutting device according to claim 1, characterized in that the bearing element for the flat blade (32) is composed of a sliding shoe (35).
4. Cutting device according to claim 3, characterized in that the sliding shoe (35) is equipped with a resilient guide component (34) which acts upon the flat blade (32).
5. Cutting device according to claim 4, characterized in that the guide component (34) is connected with the sliding shoe (35) by means of a spring element (36).
6. Cutting device according to claim 1, characterized in that for a stroke adjustment between two stroke positions of the flat blade (14) a connecting rod (8) is equipped with an angled opening (7) which is provided with a deeper (7') and a more shallow cutout (7").

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