WO1998023418A1

WO1998023418A1 - Device and procedure to break out and remove residual stampings from panels or sheet material, particularly for use in automatic flat-bed punching and/or stamping machines.

Info

Publication number: WO1998023418A1
Application number: PCT/EP1997/005779
Authority: WO
Inventors: Robert Walther
Original assignee: Rowapack Gmbh Verpackungsdesign Und Stanztechnik
Priority date: 1996-11-26
Filing date: 1997-10-20
Publication date: 1998-06-04
Also published as: AU5120398A; EP0942813B1; DE59706800D1; EP0942813A1; ATE215005T1; DE19648952C1

Abstract

This invention consists of a device and procedure to break out and remove residual stampings cut from panels or sheet material, particularly for use in automatic flat-bed punching and/or stamping machines. Needle-shaped stripping devices (12) are fitted to a stripping mould in such a way that they remain resilient and elastic around the points where they are embedded in or attached to the mould. The stripping needles (12) consist a conical or arched section which tapers to a tip (14) and accounts for more than half the total length of the needle. Preferably, the ratio R of needle length l to maximum needle diameter d should be between 6 and 80, whereby the maximum needle diameter is </= 2 mm. Stripping needles fitted on or inside the stripping mould can be combined with established cutting tools, rigid stripping pins or stripping punches.

Description

Device and method for breaking out and removing

Waste stamping parts from sheets or material sheets, especially for flat bed stamping and / or embossing machines

Description;

The invention relates to a device and a method for breaking out and removing waste punched parts from sheets or material sheets, in particular for flat-bed punching and / or embossing machines, comprising a stripping board for receiving the sheet or material sheet, an upper and / or lower stripping form as a stripping tool holding plate, the The stripping mold with stripping tools can be moved vertically towards the stripping board, further comprising recesses or openings provided in the stripping board, which are spanned by the respective waste stamped part of the material sheet.

DE 41 24 098 Cl discloses a device for removing stripped parts from a sheet of material containing blanks or the like. The sheet of material rests on a carrier plate in which openings with continuous vertical walls are provided. Each stripped part of the sheet of material spans the associated opening and, as mentioned, rests on the support plate with corresponding contact surfaces. Stripping tools made of steel strip are arranged on the tool holding plate which can be moved towards and away from the carrier plate. The stripping tools have vertical and horizontal narrow sides. Any of the known stripping tools Steel strip has at least one tip towards the carrier plate as the end of the respective vertical narrow side. The angle between the tip and the surface extending from it to the adjacent horizontal narrow side facing the carrier plate and projected into the narrow side center plane should be in a range from 20 ° to 50 °.

With the help of the technically very complex to train tip or tips, the stripping part should not slip when pressed into the respective opening, so that a safe separation and throwing off of the waste piece is possible even without additional stripping elements in the carrier plate. In order to improve the desired effect, it is proposed that the surface extending from the tip to the carrier-side horizontal narrow side of the stripping tool made of strip steel be designed so that it has the shape of an isosceles triangle, the acute angle of which is preferably 60 °. It is obvious that the corresponding grinding is production-intensive, especially when it is assumed that the tips are subject to considerable wear, so that a frequent tool change is also necessary.

From German utility model 90 03 329 it is known to use rotationally symmetrical pins with tips as stripping tools, the tips cooperating with elastic abutments arranged in the lower region of the stripping form.

When the stripping pin returns in connection with the

The stripping part is removed from the abutment. However, the rigid embodiment of the rotationally symmetrical is disadvantageous

Pins in conjunction with the elastic abutments, which are extremely susceptible to wear.

Stripping pins are known from the company publication BOBST SA, 1992, DOCtraining, the smallest diameter of which is approximately 4 mm with a free length of 35 mm. The stripping pins are hammered or inserted from the front into corresponding holes in a stripping mold and have a shoulder for this, so that the desired length Positioning can be achieved. A large number of strippers arranged in this way then serve to remove waste stampings, as already described above.

The known stripping pins are particularly unsuitable for very small waste and stripping parts. In known stripping tools, flat band-shaped elements or stamps of larger diameter are at best provided with a tip, so that there is a corresponding change of band steel or stamp and tip. The stamp and tip are fixed in shape or flat, serrated on the head or provided with a corrugated structure.

Due to the size geometry of the known stripping elements, considerable problems arise when stripping on fast-moving automatic punching machines. On the one hand, as already mentioned, the known stripping elements are too large for very small parts to be stripped, so that they cannot be removed with sufficient success. Due to the fixed active connection between the tip and the punch or steel strip, the tips cannot attack at the critical points of the cutting geometry. Due to the predetermined lines of action of the known tips in connection with the vertical narrow side of the tool according to DE 41 24 098 Cl, it is not possible to prevent torques of the parts to be broken out, so that

Malfunctions in the automatic operation of a flat bed punch are the result.

Due to the geometrical design of known tips, a large counterforce is required when touching the material sheet surface and for locking the waste punched part, which is not present in the normal punching pattern, so that additional breakpoints in the stripping or punching form are necessary.

Ultimately, the additional stops increase the

Required pressure in the stripping station of a flat-bed punching machine. In addition, undesirable vibrations of the material sheet build up, which adversely affect the positioning and rest position during the stripping process. Due to the previously mentioned problems, it was previously necessary to use bottom pins.

It is therefore an object of the invention to provide a device and a method for breaking out and removing waste punched parts from sheets or material sheets, in particular for flat-bed punching and / or embossing machines, which enables the incoming material sheet with reduced pressure force requirement in the stripping station to hold securely, to smooth and to position, as well as to safely and completely remove even the smallest waste stampings.

The object of the invention is achieved with an object according to the features of claim 1, reference being made to the solution according to claim 10 with regard to the method. The subclaims represent at least expedient further developments or refinements of the invention.

An essential basic idea of the invention is to leave the previous rigid system between the stripping mold or stripping tool holding plate and stripping tool in such a way that the stripping tools are at least partially designed as stripping needles which are flexible in the stripping form relative to their respective clamping or fastening point are flexibly movable. Due to the correspondingly slim and elongated needle shape, the desired elastic mobility is established, so that there is a safe breakout and removal, in particular of very small breakout parts.

According to the invention, the positioning of the knock-out needles is carried out in such a way that preferably three needles form a group that spans an equilateral, isosceles or uneven triangle, the needles being freely positionable in relation to critical break-out points.

For the safe and successful breaking out of larger waste stampings, such as the tapering critical ones Having sections, according to the invention a combination of the stripping needles with known stripping tools can be used.

In a preferred embodiment, the stripping needles have a greater height than the stripping tools used in combination, and it is ensured that the elastic mobility of the respective needle relative to its respective clamping or fastening point is maintained compared to neighboring stripping tools.

The needles according to the invention can be set independently, so that the number of breakpoints can be reduced or breakpoints can be dispensed with entirely.

The needle-shaped stripping tools fulfill the function of prepositioning the material sheet, pressing and holding the same, and smoothing the sheet starting from a gripper section on all sides, so that the material sheet lies flat on the stripping board. Here, too, the elasticity of the knock-out needles and the provision of specific differences in height or length of the needles from the gripper or geometric center of gravity, starting from the outside, are advantageous. Overall, undesirable swinging of the material arches and bulging of the sudden

Braking in the stripping section of an automatic punching machine is prevented, which increases the productivity and quality of the processed material sheets.

It is within the meaning of the invention that the knock-out needles can also interact with tools for edge separation or with holding blocks for severing or breaking out larger parts, but the desired elastic movement around the clamping or fastening point of the respective needle must be ensured.

The break-out needles according to the invention have a conical or arcuate section which forms a tip, this section being essentially half the length of the needle occupies. In a preferred embodiment of the break-out needles, the ratio V of needle length 1 to the largest diameter d of the needle is in the range from 6 to 80, the largest diameter of the break-out needles being in the range <2 mm.

For all-round smoothing of a sheet of material entering the stripping section of the flat-bed punching machine or a so-called blank, the stripping needles are arranged starting from the center or the geometric center of gravity of the stripping form and / or from the gripper section for fixing the sheet of material on the stripping board so that here the needles have a greater free length or height in relation to the other areas or directions. This is to be understood in such a way that the needles in the other directions, starting from the gripper or geometric center of gravity, have a decreasing length or height, so that when the stripping mold is lowered and the stripping needles are placed on the material sheet, the material sheet is smoothed on all sides in accordance with the flat stripping board he follows.

According to the invention, the stripping needles are inserted from the back into the stripping mold and fastened in this. The stripping mold, which consists of multilayer plywood glued, preferably has holes which are produced by laser radiation and which have a slightly smaller diameter than that of the needles. In order to achieve exact height and length positioning of the stripping needles in relation to the stripping mold, the stripping needles have a V-shaped or cup-shaped fastening shaft that is flush with the back of the stripping mold.

The needles are therefore inserted or hammered into the laser bores or breakthroughs produced in some other way, the fastening shaft forming a stop.

On the process side, after the stripping needles have been positioned accordingly in the stripping mold, a known relative movement between the stripping needles and the stripping needles is carried out _ _η _,

Stripping mold and the stripping board having a sheet of material. As the sheet begins to be touched by the break-out needles, the sheet is pressed, smoothed and held in the preposition. As the movement continues, the desired breaking out of the waste part is carried out with a lower pressure force requirement in relation to the prior art. Ultimately, using the knock-out needles according to the invention, when carrying out the method, it is prevented that position-changing vibrations of the arc occur. The existing ones

Lateral forces that the bow generates when swinging are absorbed by the opposing forces due to the needle elasticity of the firmly clamped needles, so that the bow is flat and overall there is a highly productive and effective automatic removal of waste parts, largely without the use of pencils.

In summary, the stripping needles represent elements which allow punctiform, elastic gripping on the waste punched part, the stripping needles not having a fixed, direct connection to other stripping tools known per se.

In particular, an upper stripping mold has stripping needles that take up a greater height on the gripper and / or inner surface section in relation to the right, left and rear edge sections, so that smoothing of the incoming material sheets is ensured.

Thanks to the needle geometry, even very small parts can be fixed at critical points, so that these small parts can be broken out successfully. The triangular arrangement of the stripping needles effectively counteracts undesirable torques of the stripping or waste parts. The punctiform contact or contact surface of the stripping needles with respect to the material sheet reduces the pressure force requirement of the stripping station.

Jamming of the waste stamping parts is effectively countered by the fact that the individual needles, known in terms of height, are used in combination.

As explained, the stripping needles can be combined with stripping lines, the stripping lines according to the invention being designed as flexible, elastic or partially elastic stripping walls. These resilient, partially elastic stripping walls, preferably made of a rubber or rubber-like plastic material, can have a conical shape, i.e. have a shape tapering away from the tool. In addition, there is the possibility of providing recesses in the tool, in particular on the stripping board, which form air discharge channels, as a result of which displaced air can escape when the panel runs in.

The invention will be explained in more detail below using an exemplary embodiment and with the aid of figures.

Here show:

1 shows a schematic diagram of a flat-bed punching machine with a stripping station;

2 shows a basic illustration of the arrangement of the stripping board and stripping mold within the stripping station and

Fig. 3 is a schematic representation of a stripping needle according to the embodiment.

The flat-bed punching machine shown in FIG. 1 has a loading and planting station 1 which has means for feeding the individual material sheets 2 to a punching station 3. Waste punched parts 6 or stripping parts remaining after punching in the punching station 3 are removed in a stripping station 4. The stripping station 4 contains a tool frame 5 for upper and lower tools and for a stripping board. After the waste stamping parts 6 have been removed, the material sheets 2 thus processed arrive at a stack delivery and discharge station 7. The performance of known flat-bed punching and / or embossing machines is in the range from 5000 to 6000 material sheets per hour, the maximum punching force being 600 t. Maximum sheet formats are in the range of 1020 x 1500mm. The gripping edge setting range for holding the material sheets takes up about 10 to 15 mm. Punching and embossing machines can process paper with a basis weight of at least 70g / sqm and cardboard or solid cardboard up to a basis weight of 2000g / sqm or corrugated cardboard up to a total thickness of approximately 4mm.

The specified sheet outputs per hour result in considerable sheet movement or transport speeds with corresponding forces when braking or accelerating the material sheets in the respective station, with the result of bulges, in particular when holding within the punching and stripping station. In addition, it is necessary to achieve positioning accuracies of the material sheets that are of a magnitude that is smaller than the smallest stripping parts.

With the aid of FIG. 2, a device for breaking out and removing waste punched parts, which are located within the breaking out station 4 according to FIG. 1, will now be explained in more detail.

The device, as shown in FIG. 2, has a stripping board 8 which is used to hold the panels or the material sheets 2. The stripping board 8 has cutouts or openings 9 in accordance with the position of the waste punched parts. Above the stripping board 8 is an upper stripping mold 10, which consists of layered and glued plywood. The stripping mold 10 serves as a stripping tool holding plate and can be moved vertically relative to the stripping board 8. The direction of movement is symbolized by an arrow. The stripping mold 10 has longitudinal bores 11 into which stripping tools 12, in the example shown in the form of a stripping needle, can be inserted and fastened. The knock-out needle 12, which is inserted into the stripping mold 10 from the rear and fastened to a clamping point 13, is capable of performing an elastic movement around the fixed clamping point 13 due to its given relationships between diameter and length.

When lowering the stripping mold 10 with the stripping needles 12, the needles 12 first touch the surface of the material sheet 2, hold and smooth it and then penetrate into the cutouts or openings 9 in the stripping board 8 with the removal and removal of the waste punched part 6.

In a further exemplary embodiment, the stripping needles 12 have a larger free, i.e., starting from a gripper section or the geometric center of gravity of the stripping board 8 or stripping mold 10. length protruding from the stripping mold 10 in comparison to the edge sections, so that with the lowering or the relative movement of the stripping mold 10 and the stripping board 8 towards one another, a smoothing of the inserted material sheets 2 takes place from the center towards the edge region, so that a safe and optimal flat, ie level contact of sheet of material 2 on the surface of the stripping board 8 is given. In order to enable a correspondingly rapid displacement of air between the material sheet 2 and the stripping board 8, holes can be provided in the stripping board.

Breaking needles are assigned to the critical sections of these parts, particularly in the case of very small waste parts.

In the case of larger pieces of waste, the stripping needles 12 can be combined with stripping tools known per se, for example in the form of stripping lines. In the latter case, however, an unimpeded lateral, elastic movement of the break-out needles around their respective clamping point, ie a corresponding lateral distance from the rigid break-out lines or break-out punches, must be observed. In addition, there is a vertical distance between the stripping needle and another stripping tool. FIG. 3 shows a particularly preferred embodiment of a knock-out needle 12. This knock-out needle 12 has a conical or arcuate section 14 forming a tip, this section 14 taking up essentially half of the free needle length 1. The maximum diameter of the needle 12 is denoted by d.

The ratio V of needle length 1 to the largest diameter d of the needle is essentially in the range from 6 to 80, the largest diameter d of the needle being <2 mm.

The end of the fastening shaft 15 of the knock-out needle 12 has a V-shaped or conical end 16 which serves to lock or knock the knock-out needle into the bores of the knock-out mold. The stripping needles are fastened in the stripping mold in such a way that the V-shaped or conical end 16 of the fastening shaft is flush with the back of the stripping mold. In a particularly preferred embodiment, the total needle length is approximately 50 mm with a tip section of 25 mm. The breakout needle is inserted with its fastening shaft and the conical end into a 15mm thick wooden plate that forms the breakout shape. The diameter of the needle according to the preferred embodiment is approximately 1.2 mm.

Especially in the case when the longitudinal bores 11 are made in the stripping mold 10 by means of a laser, the cross-sectional area of the bore with alternating micro-recesses and projections results in a firm press connection between the stripping needle 12 and the stripping mold 10, with the V or conical shape of the end 16 the desired height positioning is secured and unwanted twisting of the needle can be prevented. The exact fit or the exact attachment of the stripping needles in the stripping mold can be checked or ascertained by a quasi tuning fork test, ie striking the stripping needles. In the device for breaking out and removing waste punched parts according to the exemplary embodiment described, first of all in terms of process technology, the relative movement known per se between the stripping form having the stripping needles and the one having a sheet of material is used

Stripping board executed. When the sheet of material begins to be touched, the needles are used to preposition, press and smooth and hold the sheet. As the movement continues, the desired breakout of the waste part occurs with less pressure force in the

Comparison to the state of the art. The elasticity of the knock-out needles prevents an undesirable position-changing swinging of the sheet, so that there is a higher productivity or sheet output per unit of time.

Reference character list

1 loading and planting station

2 sheets or sheet of material

3 punching station

4 stripping station

5 tool frames

6 waste stamping part

7 stack delivery and delivery station

8 stripping board

9 cutouts or openings

10 stripping mold

11 longitudinal holes

12 stripping tools or stripping needles

13 clamping point

14 tip section

15 fastening shaft

16 V or conical end of the fastening shaft

Claims

claims

1. Device for breaking out and removing waste punched parts (6) from sheets or material sheets (2), in particular for flat bed punching and / or embossing machines, comprising a stripping board (8) for receiving the sheet or material sheet (2), an upper and / or lower stripping mold (10) as a stripping tool holding plate, the stripping mold (10) with stripping tools (12) being movable vertically towards the stripping board (8), recesses or openings (9) provided in the stripping board (8), which are separated from the respective waste punching part (6 ) of the material sheet (2) are spanned, characterized by substantially vertically fixed in the stripping mold (10) needle-shaped stripping tools (12), the stripping needles (12) thus formed being resiliently movable about their respective clamping or fastening point (13).

2. Apparatus according to claim 1, characterized in that for breaking out the smallest waste punched parts (6) preferably a combination of three arranged in irregular or regular triangular breakout needles (12) are each fixed in the breakout mold (10).

3. Apparatus according to claim 1 or 2, characterized in that the break-out needles (12) have a conical or arcuate, tip-forming section (14), this section occupying substantially half the needle length.

4. Device according to one of the preceding claims, characterized in that the ratio V of needle length 1 to the largest diameter d of the needle substantially in the range of

V = 6 to 80, the largest diameter being <2mm.

5. Device according to one of the preceding claims, characterized in that in addition to the stripping needles (12), the stripping mold (10) has known rigid cutting-like stripping tools, stripping pins and / or stripping punches, the other stripping tools only indirectly via the stripping mold (10) communicate with the knock-out needles (12).

6. The device according to claim 5, characterized in that the stripping needles (12) protrude relative to the other stripping tools and are laterally spaced from them so that the elastic mobility around the clamping or fastening point (13) is retained.

7. Device according to one of the preceding claims, characterized in that the stripping needles (12) on the stripping mold (10) from the center or the geometric center of gravity of the stripping mold (10) and / or of the gripper section for fixing the sheet of material (2nd ) starting from the stripping board (8) have a greater free length or height relative to all other areas or directions, so that the stripping mold is lowered - 10 -

(10) and attaching the break-out needles (12), the material sheet (2) is smoothed on all sides.

8. Device according to one of the preceding claims, characterized in that the stripping needles (12) from the back of the stripping mold (10) are inserted and secured in this.

9. The device according to claim 8, characterized in that the stripping needles (12) have a V- or conical or goblet-shaped end (16) of the fastening shaft (15), this end (16) flush with the back of the stripping mold (10) completes.

10. A method for breaking out and removing waste stampings with a device according to one of claims 1 to 9, characterized by

Carrying out a relative movement between the stripping mold (10) having stripping needles (12) towards the stripping board (8) receiving a material sheet (2), the incoming movement to be braked (2) being pressed, smoothed and held to maintain a flat position with the relative movement and as the relative movement continues, the waste parts (6) break out and position-changing machine vibrations or swinging of the bow (2) are prevented by the needle elasticity.