DK173161B1 - Method and machine for cutting corners on a sheet material - Google Patents

Abstract

In a method and a cutting machine according to the invention a pile (1) of sheets can be placed on a feeding plane and then carried into a given position in the cutting machine, wherein a pressing foot (7) secures the pile (1) while four cutting knives (11) are pressed down through the corners (24) of the pile against lower knives (12), which ensures a high cutting capacity and a perfect cutting result, the cutting being uniform in the entire height of the pile (1). The machine may be built up with an adjustable part to the effect that the machine can cut in different widths of sheet, and the individual knives (11, 12) may be adjustable for different lengths of sheet. A universal machine is thus provided, which is easily and quickly adjusted for different formats, in addition to which it is easily operated since the pile (1) can be inserted, cut and removed through the machine in a continuous procedure. <IMAGE>

Description

in DK 173161 B1

The invention relates to a cutting machine according to the preamble of claim 1.

As an example of the use of a sheet material of | eg. metal foil-coated cardboard with cut corners should be mentioned a food substrate such as sliced fish or meat, which is then wrapped in transparent plastic foil to form a sales packaging.

The round corners are partly harmonious to the appearance of the packaging 10 and partly protect against damage to the plastic film, especially where it shrinks on the packaging. j

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Furthermore, the rounded corners are used as a natural form of e.g. playing cards and other cards which need to be handled in a convenient manner and where pointed corners would be troublesome.

Finally, one can mention books, including directories and other reference books, where sharp corners will be worn or bent, while rounded corners provide an ideal page shape.

20: Such rounds are usually made in a cutting machine. An example of such a machine is known from DE 1.268.588, which!

deals with a machine that can round all four corners in one and I

same workflow. This is done using four knives, which! 25 is brought down simultaneously, cutting off the corners of rectangular sheets.

This known machine is preset to a specific format size, e.g. playing cards. A stack of rectangular {30 cards is placed in a side guide tray, after which four knives with press plungers are moved down to cut the four corners.

After the cutting is completed, the knives and pistons are lifted, 35 after which the cut cards can be removed from the tray and a new stack inserted.

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The cutting is done only by means of the four movable blades, Λ which limits the height of the stack and thus the cutting capacity of the machine, since the cutting will be imprecise and the cuts of poor quality if the stack becomes too high.

5 This disadvantage is mainly due to the insufficient control of the blades near the machining site.

Thus, this limits the utility of the machine, being limited to a particular format, partly to a manual feeding and removal of the sheet stack, and partly to a cutting capacity limited to a relatively low stack.

From US-A-3,125,920 a machine according to the preamble of claim 1 is also known.

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Another machine for rounding corners on a stack of paper is known from US Pat. 3656387. This machine is hand operated and is unable to cut all four corners of the stack into one operation. However, it has sub-blades under the cutting blades.

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The disadvantage of the aforementioned known machines is that the cutter on the cutting blades extends in a plane parallel to the sheet, whereby each corner forces its way through a sheet with the total length of the cutter acting simultaneously. In this way it is not possible to make a completely clean and sharp cut.

The object of the invention

It is the object of the invention to remedy these deficiencies and limitations of the known machines for cutting corners 30 on a sheet stack, and this is achieved by providing a cutting machine according to claim 1. The cutting blades extend along an upwardly directed arc between the outermost points of the blades. glow. The cutting blades taper to form a wedge the tips of which are constituted by the lowest points of the cutting, thus extending the outer ends as attack tips through the stack.

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The cutter on each knife successively forces its way through a sheet, and the intermediate and underlying material is compressed during the cutting itself, resulting in a precise and clean cut.

5 A cutting machine of unprecedented high capacity is thus provided, with the effect that the height of the stack can be up to 500 mm with a perfect cutting result, partly due to the combined inserts comprising a cutting knife and a lower knife, thereby ensuring a uniform cutting throughout the entire stack and partly because the presser foot is pressed down to ensure that the stack is firmly held during cutting.

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In addition to the increased cutting capacity and the perfect cutting result, the task of the continuity allowed by the machine is simplified, 15 since a stack can be fed into the machine, continue in the same plane inside the machine and after the cutting is moved out through the opposite end of the machine.

The cutting can thus be automated, the machine becomes a continuous machine, thereby significantly reducing running costs.

Fast feeding and removal is ensured by letting a new stack push the finished stacks out of the machine. This increases the machine's productivity and reduces the manual work of cutting.

By designing the machine so that the blades are adjustable according to the width as well as the length of the stack, it becomes possible to cut different sizes of sheets into one machine.

The machine can be adjusted using a simple adjustment device. j

This enables an unprecedented high degree of customization all). 35 for different sheet sizes and without compromising the machine's unique cutting properties. in 4 DK 173161 B1

By mounting each cutting knife on a knife holder and mounting the holder on a beam or head which is slidable on a column guide by means of a working motor, perfect control and pressing of the knives is ensured, and the distance between the knives can be adjusted by adjusting the knife holders. .

By mounting each lower knife to a holder provided with a guide on which the cutting blades can slide, a perfect cutting result, partly a clean cut, and partly a gentle cutting 10 for the blades is ensured because of the precise interaction between the cutting blades and the lower knife.

By cutting after a circular cut, thereby forming the lower knife as a circular disc shaped blade blank, which can be rotated when worn, a considerable saving and reduction in the number of tool changes is achieved.

The invention will be described in more detail in the following section with reference to the drawing, in which: FIG. 1 shows a cutting machine according to the invention without sheet stack; FIG. 2 shows, in simplified form, a sheet stack during insertion into the machine; FIG. 3 shows the stack after insertion and with the presser foot depressed; FIG. 4 shows the stack during the cutting; FIG. 5 shows the stack on its way out of the machine; FIG. 6 shows details of the cutting blades and their control; FIG. 7 shows the cutting blades during their pressing and cutting; FIG. 8 shows the shape of the knife set, and 5 figure 9 shows the interaction of the knife set.

Description of the embodiment

An example of a cutting machine according to the invention is shown in FIG. First

The machine is built on a frame with legs on which the transport and cutting unit is built.

The transport unit comprises an insertion plane shown to the left of the frame, which plane is provided with a longitudinal guide 2 extending in the machine's conveyor direction and which is adjusted so that a sheet stack not shown can be placed on the plane with its one end face resting against the handlebar 2.

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Hereby, an arm 3, which is moved by a working motor (not shown), can push against the rear edge of the stack and thereby insert the stack into the cutting unit itself.

The cutting unit is made up of two sections whose spacing can be adjusted according to the width of the stack.

Each section comprises a cylinder 8 with a piston rod connected to a bridge or beam 9 which can slide up and down 30 on a column guide 10 which rests on a foundation of the frame.

At the bottom of the column guide, spacer bushes 18 are provided to limit the downward movement.

The work motor 8 is mounted on a fixed bridge or beam 20, resting on the column guide 10.

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The distance between the two sections can be adjusted by means of a handwheel 17 so that the machine can be adjusted to the desired cutting width of the stack.

5 To control the stack during insertion into the machine, four guides 4 are mounted between which the stack can be placed. To limit the stacking insertion into the machine and to determine the stacking position, an end stop 5 is mounted which can be raised and lowered by means of a working motor 6.

The position of the end stop can be adjusted as its motor 6 with bearing can be displaced in a groove 21 on the upper bridge 20 and secured to it.

When the stack is inserted into the machine between the guide 4 and 15 the end stop 5, a presser foot 7 is pressed down by means of a working motor, which presser foot is designed as a plate which compresses and retains the stack during the subsequent procedure.

Finally, there is the cutting device itself, which comprises four cutting knives, each attached to its knife holder 26, which is slidably mounted on the knife holder bridge 9. The distance between the cutting knives can thereby be adjusted according to the length of the stack.

The knife sets each comprise a sub-knife 12, which is secured in a holder 13, which also carries a column guide 14 for the cutting knife holder 26 so that precise control is ensured and thus cooperate between the individual upper and lower knives in each knife set.

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Each holder 13 can be displaced between a guide rail 15 and a guide piece on the foundation such that the distance between the cutting sets can be precisely adjusted in the longitudinal direction of the machine.

35 Opposite the entry plane is a conveyor belt 22,! which can move the pre-cut stack away from the cutting unit.

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Finally, a cabinet 23 is mounted on the frame into which the electrical controls cabinet is built and which controls the individual functions of the machine by means of commonly known hydraulic and / or pneumatic control means for the working motors.

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The cutting machine operates as described below with reference to FIG. 2-9.

The cutting machine is adjusted according to current stack dimensions so that the knife sets 11, 12 are precisely positioned next to the corners of stack 1 when the stack 1, as shown in fig. 2 is located in the machine between the guides 4 and the end stop 5, as shown in Fig. 3.

In this position, the presser foot 7 is pressed down so that the stack 1 15 is held compressed in the cutting position.

Then the cylinders 8 are actuated and the upper knives on the bridges 9 are pressed down through the corners 24 of the stack 1.

20 After cutting the corners, the bridges 9 with the cutting blades 11 are raised at the same time that the presser foot 7 and the end stop 5 are raised, so that the corner cut stack 1 can be carried out on the conveyor belt 22, as shown in Fig. 5.

25 This stacking is effected by means of the moving member 3 as this leads a new stack 1 into the machine for cutting.

After this, the cutting process can be repeated and thus corners can be cut in a continuous automated process.

In this way, up to 30,000 sheets can be cut per piece. which far exceeds the number of sheets which can be cut by the known machines.

When this production capacity can be achieved, it is not due to at least the precise control of the cutting blade movement and the design of the knife set itself.

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As shown in FIG. 6, the cutting blades 11 are mounted on the holder 16, which is guided by the column 14, which in turn is fixed with the lower knife 12. Hereby the cutting blade 11 is guided throughout its stroke, and a completely uniform cutting of the corners 24 is achieved, the control extending in the entire cutting length.

In FIG. 7 is shown how the cutting edge 25 of the cutting knife 11 fixes the sheets in the stack 1 so that the subsequent cutting of the corners 24 takes place in a state where the corner material is compressed and tensioned with respect to the knife edge of the cutting knife 11.

As shown in FIG. 8, the cutting blades 11 are formed with a notch which is circularly cut, and since the knives are at the same time 15 wedge-shaped, it is formed in FIG. 7 shows a sharp cutter 25 with an arcuate intermediate cutter.

When this cut is to be sharpened, this is done by a simple grinding of the inclined underside.

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The lower notch is shown in FIG. 8 and 9. It is formed as a circular disc 27, substantially the same diameter as the cutting knife 11. A screw 28 retains the disc 27 to the holder 12 such that when the circular cutter 30 is worn, the screw 28 25 can be loosened, after which the knife 27 can be turned by means of a handle with a pin in the holes 29, until a new cutter 30 is advanced under the cutting knife 11.

By this extremely simple design of the knife set, 30 can be cut precisely and uniformly through a sheet stack of up to 500 mm in height, and without the cutting edges being severely loaded, thereby making the stand time very high. Furthermore, the quality of the cutting is high, so that the rounding will be the same throughout the height of the stack.

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Claims (5)

9 DK 173161 B1 1. A cutting machine for automatically cutting corners (24) of a stack (1) of preferably identical rectangular sheets of 5 material, in particular cardboard, paper, fabric, plastic, metal foils and combinations of such materials, with four cutting knives (11) movable between a free position above the stack (1) and a lower position, the machine comprising: an insertion plane, for positioning the stack (1) 10 so as to rest with its end surface against a guide (2), which runs in the longitudinal direction of the machine; a first moving means (3) for moving the stack (1) along the guide (2) in the longitudinal direction of the machine into a cutting unit; a presser foot (7) movable back and forth between a free position 15 above the top of the stack and a retained position in which the presser foot (7) is pressed down against the top of the stack 1; means for moving the presser foot (7); means (8) for moving the cutting blades (11) back and forth between a free position over the top of the stack and the lower position, cutting all four 20 corners (24) of the stack (1) simultaneously as the cutting blades (11) move downwardly from their free position to their lower position; and other movable means (22) for moving the stack (1) out of the cutting unit in the same direction as the stack moved into the cutting unit after the presser foot (7) and cutting blades (11) are returned to their respective free positions by their respective means , characterized in that the cutting unit is provided with lateral guide (4) for controlling the stack (1) as it moves in position into the cutting unit, in that an end stop (5) is movable between a stop position by means 30 (6). , in which it may 'abut against the front of the stack, and a free position above the stack, the first moving means (3) moving the stack until the front of the stack abuts the end stop (5); By providing four sub-blades (12), one below S 35 each stacking corner, to support the stack during j in cutting, the sub-blades configuration being essentially! 10 DK 173161 B1 is complementary to the shape of the cutting blades (11) in the area J along which the cutting blades are made, so that the cutting blades (11) and the sub blades (12) can cooperate to give a cutting effect by moving the cutting blades into a position 5 in the cutting edges of which are cut below the upper surfaces of the cutters, and that the cutting blades (11) extend along an upwardly directed arc between the outermost points (25) of the cutters on said cutting blades (11), which simultaneously taper to form a wedge-shaped cut 10 A cutting machine according to claim 1, characterized in that the cutting unit comprises two cutting sections (8, 9, 10), each equipped with two sets of knives (13, 14, 26) having a cutting knife (11) and a lower knife. (12), the distance between said 15 cutting sections can be adjusted according to the width of the stack (1) and the distance between the knife sets for each cutting section can be adjusted according to the length of the stack. A cutting machine according to claim 2 or 3, characterized in that 20 each cutting knife (11) is mounted on a knife holder (26) which is fixed to a beam (9) slidable on a column guide (14) by means of of a working cylinder piston rod. A cutting machine according to claim 3, characterized in that each lower knife (12) is mounted on a holder (13) which is provided with a column guide (14) for the cutting blade holder 26. A cutting machine according to claims 1-4, characterized in that the cutting shape of the blades (11, 12) is a circular section and that the lower knife (12) is formed as a disc (27) with a circular cutter (30) which can be rotated about its center axis (28) and attached to its holder (12).