EP0697940B1 - Device, clamping tool and process for breaking away cuttings when cutting out blanks from cardboard - Google Patents

Abstract

PCT No. PCT/EP94/01569 Sec. 371 Date Nov. 14, 1995 Sec. 102(e) Date Nov. 14, 1995 PCT Filed May 14, 1994 PCT Pub. No. WO94/26480 PCT Pub. Date Nov. 24, 1994In a device and a process, as well as a clamping tool for breaking away blank cuttings during the cutting out of cardboard in an automatic cutting press with a breaking away tool comprising breaking away shafts (9), a matrix (11) and a clamping tool for holding the cutting (6) to be broken away through the matrix openings (12) and hanging on a cardboard bridge (13) on the cardboard blank (7), the clamping tool is constructed as a one or multiple-part, flat element (16), which supports flat the matrix (11) and is in elastic operative connection with the breaking away shafts over the cuttings (6) at the time of breaking away. According to a further development of the invention, the flat element (16) is covered with an elastic covering layer (17) and with a multi-part construction the flat element (16) comprises clamping segments cyclically rotatable about its longitudinal axis, so that during rotation openings are freed between the clamping segments for discharging the separated cuttings (16). The proposed device can be used for different blank types and is suitable for reequipping conventional automatic cutting presses.

Description

• mit einer Matrizenplatte, deren Öffnungen geringfügig größer als die auszubrechenden Abfallteile sind,
• und mit oberhalb der Matrizenplatte angeordneten, taktweise senkrecht bewegbaren Ausbrechwerkzeugen
• sowie mit unterhalb der Matrizenplatte taktweise senkrecht bewegbaren Klemmwerkzeugen zum Erfassen und Abtrennen der Abfallteile im Zusammenwirken mit den Ausbrechwerkzeugen.

The invention relates to a device, to a clamping tool and to a method for breaking out cutting waste when punching cardboard in an automatic punching machine.

• with a die plate, the openings of which are slightly larger than the waste parts to be broken out,
• and with stripping tools arranged above the die plate, which can be moved vertically in cycles
• as well as with clamping tools that can be moved vertically at intervals below the die plate for grasping and separating the waste parts in cooperation with the stripping tools.

As stripping tools, stripping pins or equivalent pressure stamps or the like which can be placed on the waste parts from above can be used.

DE-U-90 03 329 describes a device of the type mentioned at the outset for breaking out cutting waste. The clamping tools are abutments, which are arranged movably or resiliently within the respective opening. In their rest position, the abutments reach under each of the waste parts that are located in the cardboard sheet. When the waste parts are moved through the stripping tools, in particular stripping pins, the waste parts can be transferred at an angle to the cardboard sheet. The abutments are formed in the various embodiments by one or more tongue-like springs, by sections of one or more rotatable bodies or by elastic lugs or bristles.

JP-A-4 201 100 describes an apparatus for breaking out cutting waste when punching cardboard in an automatic punching machine. The device has a flat support plate which has a sponge-like flat elastic layer on its top. The device works in cycles. The flat elastic layer is arranged on the support plate such that it can move in the vertical direction below a die plate.

In the known high-speed automatic punching machines for punching cardboard sheets, for example for the production of folding boxes, the waste parts remaining after the punching process between the cardboard blanks are held on small cardboard bridges, so that the cutting waste does not fall off the punching plate and can hinder the subsequent punching process punched cardboard sheets that are still sufficiently connected due to the cardboard bridges then reach the stripping station via gripping devices the punching machine, in which the cutting waste is broken out of the cardboard sheet and falls into a waste container. During the stripping process, the punched cardboard sheet lies on a die plate such that its openings are congruent with the waste parts of the cardboard sheet. The cutting waste is now gripped or clamped by a stripping tool or clamping tool brought up from above or below in the form of stripping pins and opposing, usually resiliently mounted clamping pins and, when the two tools move downwards together, pressed through the die opening and thus broken out of the cardboard sheet. While the tool with the clamping pins moves further down to ensure that the cut waste that has been broken out can be removed effortlessly, the stripping pins move up again immediately to enable the following cardboard sheet to be fed.

There are also stripping devices in which no clamping or lower pins are provided. But when the blank waste is broken out without appropriate guidance or clamping from below, faults easily result from stuck - because not completely broken - waste.

The upper and lower stripping or clamping tools, like the die plate, are advantageously fastened in slide-in frames which are used in slides in the break-out station.

The stripping pins and the clamping pins are usually set by hand exactly in accordance with the shape and arrangement of the openings in the die plate or the cutting waste, with a larger portion per waste part Number of stripping pins must be exactly opposite to individual clamping pins. While the arrangement of the stripping pins according to the respective shape of the cutting waste is already programmable for the different types of cutting and can be done by inserting them into automatically generated holes in a mounting plate, the clamping pins are manually moved on rails that can be moved in a frame - between which the waste parts in the Litter bins can fall - precisely aligned with the stripping pins.

The manual, precise positioning of the clamping pins requires a lot of skill and experience and is also very time-consuming, especially from the point of view that the clamping pins have to be set each time the blank is changed. On the other hand, the stocking of many frames with clamping pins already set earlier according to the respective type of cutting is very space-consuming and, above all, also cost-intensive due to the expensive frames.

It is therefore an object of the invention to provide a device and a method of the type mentioned above for breaking out cutting waste, which makes the time-consuming, manual setting of the clamping pins on the lower slide-in frame corresponding to the respective cutting type and flush with the break-out pins and one for all or Provides as many types of cuts as possible for universally usable stripping and clamping tools, which at the same time ensure that the broken-out waste parts are discharged safely.

• das Klemmwerkzeug als flächenhaftes Element ausgebildet ist,
• das die Öffnungen der Matrizenplatte übergreifend mit seiner Oberfläche an die Matrizenplatte andrückbar und
• mit den Ausbrechwerkzeugen über die Abfallteile zum Ausbrechen derselben in Wirkverbindung bringbar ist.

According to the invention the object is achieved in a stripping device for cutting waste according to the preamble of claim 1 in that

• the clamping tool is designed as a flat element,
• the surface of the openings of the die plate can be pressed against the die plate and
• can be brought into operative connection with the stripping tools via the waste parts for stripping the same.

As a result of the two-dimensional design of the clamping tool, which extends beyond the contours of the openings, the die plate is contacted over the entire area from below and can consequently be made with a small thickness. Due to the resulting small depth of the die opening, an elastic clamping connection between the stripping pin, the waste part and the clamping surface of the clamping tool can be achieved even with a flat design of the clamping tool, whereby a flat contact between the waste part and the clamping tool is achieved for reliable grasping of the waste part the extremely small distance between the stripping pin and the flat element prevents the stripping pin from sliding off the waste part and a clamp connection is established.

The invention also relates to an embodiment in which the break-out or die plate is made as thin as, for example, a film and is supported by a flat element without an elastic surface. In this case, the waste part is clamped after an extremely short path of the break-out pins after they have been placed on the waste part. Because this short path corresponds approximately to the thickness of the wafer-thin die plate.

The elastic operative connection between the clamping tool designed as a flat element and the knock-out pins is produced in a particularly simple manner according to a development of the invention in that the clamping tool is formed by a flat, elastic cover layer with a smooth surface arranged on a solid, flat base. In an embodiment of the invention, the elastic cover layer consists of a foam that compresses when the clamping tool designed as a flat surface is pressed onto the die plate and bulges into the die openings and thereby clamps the waste part between the stripping pin and the flat clamping tool and causes this during the downward movement of the Stripping and clamping tool also retained, thus ensuring the safe holding and breaking out of the waste part.

In the case of a one-piece design of the clamping tool designed as a flat element, the separated waste parts are removed by wiping or blowing devices.

According to a development of the invention, the clamping tool in the case of a multi-part design consists of rotatable clamping segments for the cyclical formation of openings in the clamping surface, in order to thereby cause the broken-off waste parts to be thrown off and carried away.

The clamping segments are preferably around their longitudinal axis in time with the upward and downward movement of the insertion frame for the clamping tool, preferably by 90 ° rotatable, in the initial length on the die plate a flat, contiguous clamping surface and, during the downward stroke, components with the cross section of an equilateral triangle, whereby the outer surfaces with the elastic cover layer are occupied. As a result, a different clamping surface is available for the clamping process in each stripping cycle, while when the clamping surface changes due to the rotation of the clamping segment, the separated waste parts fall off the previous clamping surface and pass through a hole formed between the clamping segments.

Alternatively, the clamping tool according to the invention is formed from plate-like clamping segments rotatable about its longitudinal axis with an elastic cover layer provided on both sides, the plate-like clamping segments for forming openings between the clamping segments and for throwing off the waste parts after a breakout stroke during the downward or upward stroke, in each case by at least 90 ° are rotated.

Preferably, the plate-shaped clamping segment is covered on one side with the elastic cover layer and is folded in the work cycle to form ejection openings during the downward stroke by a certain at least 90 ° bearing angle and folded back into the starting position on the subsequent upward stroke, in order to thereby separate the separated waste parts from the clamping surface remove.

To generate the cyclical rotary movement of the clamping segments, drive motors are attached to the mounting frame of the device, which are operatively connected to the axes of the clamping segments for the rotary drive thereof and are controlled synchronously with the drive system of the automatic punching machine. The drive motors are otherwise controlled so that the clamping segments are driven in the same direction of rotation during the downward stroke and the upward stroke, unless it is used to swing back and forth plate-shaped clamping segments. In the latter case, a plate-like clamping segment is just a folding movement executes and then folds back into the starting position, a single drive which effects the reciprocating movement of the clamping segment is provided.

Alternatively, the clamping tool, without the elastic cover layer, is designed as an overall elastic or elastically supported, single or multi-part flat element, or the stripping pins are elastically supported and the single or multi-part flat element itself is not elastic, as already explained above .

The present invention provides a universal tool, that is to say for different types of cuts and arrangement of cuts, for cutting out scrap waste of various shapes, sizes and arrangements, which can also be used without problems in conventional stripping stations and allows simple retrofitting of existing systems (cf. claim 19 ).

There is no need for the known stripping tools for each individual type of cutting, which can only be carried out by hand by setting the lower clamping pins in exactly the correct position to the upper stripping pins, which is very time-consuming and also requires skill and experience. On the other hand, cost-intensive storage with a high space requirement is not necessary for the frames to be equipped with the lower clamping pins or even provided with clamping pins for different types of cutting. The function of the tool proposed according to the invention is simple and reliable, since the flat design of the clamping tool is suitable for any shape of the waste part to be broken out or the die opening and is also very narrow Cutting waste can be detected by the clamping tool. The intermittent opening of the clamping surface in a multi-part clamping tool formed from clamping segments ensures, on the one hand, that the waste separated from the cardboard blanks is safely discarded without additional aids and can also be driven on the drive side by simple drives with a synchronization to the lifting movement, e.g. B. a conventional slide-in frame for the clamping pins.

Further refinements of the invention can be found in the subclaims.

Part of the invention is also a clamping tool according to claims 20 and 21 and furthermore a method according to claims 22-23.

An embodiment of the invention is explained in more detail with reference to the drawings.

Fig. 1

eine perspektivische Ansicht der Ausbrechstation eines Stanzautomaten mit einem Aufnahmerahmen für das Ausbrechwerkzeug, einer Matrizenplatte und einem Klemmwerkzeug und

Fig. 2 - 5

eine schematische Darstellung des Ausbrechvorgangs unter Verwendung eines flächigen Klemmwerkzeugs.

Show it:

Fig. 1

a perspective view of the stripping station of an automatic punching machine with a receiving frame for the stripping tool, a die plate and a clamping tool and

Figs. 2-5

a schematic representation of the stripping process using a flat clamping tool.

The stripping station of an automatic punching machine for cardboard blanks essentially consists of the three holding frames 1, 2 and 3 for the stripping tools, which are arranged one above the other and can also be designed as insertion frames for retrofitting, the die plate 11 and the clamping tools.

In the holding frame 1 there is a holding plate 4, into which holes 8 are made in accordance with the shape, size and arrangement of the waste parts 6 to be broken out of the cardboard blank 7, in which knockout pins 9, which form the knockout tool, are fastened. Elastic, block-shaped hold-down devices 10 for the cardboard blanks 7 are also attached to the underside of the receiving plate 4.

Another receiving frame 2 with lateral holding rails 15 serves to receive the die plate 11, in which the waste parts 6 between the cardboard blanks 7 in the form and arrangement are provided identical die openings 12 which are slightly larger than the waste parts 6. The cardboard sheet 5 punched in the punching device is held together by small cardboard bridges 13 left between the waste parts 6 and the cardboard blanks 7, so that the cardboard sheet 5 can be completely removed from the punching device by means of grippers and an accident due to loose waste parts 6 in the punching area is excluded. In Fig. 1, the punched cardboard sheet 5, which is in the correct position on the die plate 11 before the waste parts 6 are broken out and is essentially identical to the latter in plan view, is indicated by the dashed line 14.

The clamping tool is finally received by a further receiving frame 3. The clamping tool is designed as a multi-part, flat element 16, which consists of triangular cross-sectionally, on the end faces of the mounting frame 3 rotatably mounted clamping segments 16a. The outer surfaces of the clamping segments 16a form firm, flat bases 17b and have an elastic cover layer 17, which represents the actual clamping element.

The rotationally movable clamping segments 16a are driven in synchronism with the usual cyclical upward and downward movement of the receiving frame 3 via a gear (not shown) arranged on the receiving frame 3 and provided with a drive motor. In this way, a clockwise and preferably modulatable rotary movement of the clamping segments 16a takes place by a certain angular amount.

The function of the cutting device for cutting waste shown is described as follows:

According to the shape, size and arrangement of the cardboard blanks 7 to be produced with the waste parts 6 in between, the bores 8 in the mounting plate 4 and the die openings 12 in the die plate 11 are automatically generated according to a predetermined program and the stripping pins 9 are inserted into the bores 8 as well as the Hold-down device 10 attached to the mounting plate 4. After the mounting plate 4 has been inserted into the mounting frame 1 and the die plate 11 into the holding rails 15 of the mounting frame 2, the mounting frames 1, 2 thus prepared are pushed into the stripping station of the automatic punching machine.

For the accommodation of the clamping tool, a mounting frame 3, which is usually used in break-out stations for fastening the clamping pins serving as counterholders for the waste part, is preferably used as the receiving frame 3. This makes it possible to retrofit break-out stations of conventional punching presses with the new clamping tools in a simple manner or to use differently designed clamping tools or optionally to use the frames with the conventional clamping pins.

The functional effect of the clamping tool in the form of a flat element with an elastic cover layer 17 in connection with the stripping pin 9 is described below with reference to FIGS. 2 to 5, FIG. 2 the position before stripping, FIG. 3 the position at the beginning of the stripping process, FIG 4 shows the position after breaking out and FIG. 5 shows the position when the clamping segment tilts to remove the waste part and cardboard sheet newly placed on the die plate 11.

The punched cardboard sheet 5 deposited on the die plate 11 by means of a gripper (not shown) is held on the die plate 11 by the hold-down device 10 after the holding frame 1 has moved downward. At the same time, the entire surface of the flat element 16 with the clamping segments 16a presses against the die plate 11 from below. On the one hand, the die plate 11 is supported from below and, since it now only has to absorb small forces during the breaking-out process, can be of comparatively small thickness will. The low thickness of the die plate and the elastic design of the surface of the clamping segments 16a, on the other hand, cause the elastic cover layer 17 made of foam to bulge into the die opening 12 and, as can be seen from FIG. 3, this bulge 17a elastically against the underside of the waste part 6 presses and thus clamps the waste part 6 between the bulge 17a and the stripping pin 9. In the following stripping process - during the downward movement of the stripping pin 9 and the clamping tool 16 - the waste part 6 is supported flatly and taken along until the cardboard bridge 13 is torn off between the cardboard blank 7 and the waste part 6 and the subsequent ejection from the die opening 12, so that sliding of the stripping pin 9 on the waste part 6 is avoided and safe stripping is ensured.

The elastic bulging of the elastic cover layer 17 made of foam is not required if the die plate 11 is extremely thin and the flat element 16 is not elastic (not shown), so that the underside of the waste part 6 already touches the flat element 16 when the cardboard sheet 5 is placed on it or almost touched, but at the latest after placing the stripping pin 9 on the top of the waste part 6.

While the receiving frame 1 with the stripping tools then moves upwards and a new punched cardboard sheet 5 is placed on the die plate 11, the downward stroke of the receiving frame 3 is continued in order to perform a further function of the clamping tools designed as a flat element 16, namely the ejection process for the separated waste part 6, to effect. During the downward movement of the receiving frame 3, the gear, not shown, gives the clamping segments 16a a rotary movement of at least 60 °, but preferably of 90 °. The clamping surfaces of the clamping segments 16a go into an inclined position (FIG. 5) and then at a 90 ° rotation into a vertical position (not shown), so that the waste part 6 slides securely from the clamping surface and through the rotation of the clamping segments 16a passes between these intermittently formed openings into a waste container (not shown) arranged below the receiving frame 3. At the end of the downward stroke, the triangular clamping segments 16a assume the position shown in broken lines in FIG. 1 with a vertical (60 ° rotation) or oblique (90 ° rotation, not shown), upward-pointing tip.

During the subsequent upward movement of the receiving frame 3, the rotational movement of the clamping segments 16a is continued by a further angle of 60 ° with a 60 ° rotation for a downward stroke and of 30 ° for a 90 ° rotation with a downward stroke. As a result, the waste part can still fall off the clamping surface of the clamping segment 16a during the upward stroke if, in exceptional cases, it has not already fallen off during the downward stroke.

No matter how you choose the angle of rotation of the clamping segments 16a and their modulatable rotational speed, at the end of the upward stroke there is always a new, closed, elastic surface available for grasping the waste parts and for the next stripping process.

In order to ensure an exact horizontal position of the respective clamping surfaces of the clamping segments 16a after each upward stroke of the slide-in frame 3, a trailing brake is expediently integrated into the drive system.

Claims (23)

1. Device for breaking away blank cuttings during the cutting out of cardboard in an automatic cutting press,

   - with a matrix (11), whose openings (12) are slightly larger than the cuttings (6) to be broken away,

   - and with cyclically vertically movable breaking away tools positioned above the matrix (11),

   - as well as with cyclically vertically movable clamping tools below the matrix (11) for gripping and separating the cuttings (6) in conjunction with the breaking away tools, characterized in that

   - the clamping tool is constructed as a flat element (16),

   - engaging over the openings (12) of the matrix (11) with its surface it can be pressed onto said matrix (11) and

   - is operatively connectable with the breaking away tools over the cuttings (6) for breaking away the latter.
2. Device according to claim 1, characterized in that the element (16) is in one or more parts and has a flat, elastic covering layer (17).
3. Device according to claim 2, characterized in that the flat, elastic covering layer (17) is made from foam with a smooth surface.
4. Device according to claim 2 or 3, characterized in that the elastic covering layer (17) for supporting the cuttings (6) on pressing on the matrix (11) curves in with outward curves (17a) into the openings (12) of the matrix (11) until engagement takes place with the lower face of the cuttings (6) for jamming, entraining and breaking out the cuttings (6) jamed between the breaking away tools and the outward curves (17a).
5. Device according to one of the claims 1 to 4, characterized in that the element (16) in multipart construction comprises rotary clamping segments (16a) forming a cohesive, planar surface on the matrix (11) in a starting position, for the cyclic production of openings in the clamping face between the clamping segments (16a) spaced from the matrix (11) and for ejecting the cuttings (6) for the removal thereof from the breaking away station.
6. Device according to one of the claims 1 to 5, characterized in that the clamping tool forming a planar clamping and supporting face comprises clamping segments (16a) provided on all sides with the elastic covering layer (17), cross-sectionally assuming the shape of an equilateral triangle and rotatable about the longitudinal axis with the cycle of the downward movement of the receiving frame (3) by an angle of e.g. 60 or 90° or more.
7. Device according to one of the claims 1 to 5, characterized in that the clamping tool is formed from plate-like clamping segments rotatable about the longitudinal axis in the cycle of the upward and downward movement of the receiving frame (3) and closely engaging for forming a through clamping face in the starting position.
8. Device according to claim 7, characterized in that the plate-like clamping segments are covered on all sides with the elastic covering layer and in a working cycle are in each case rotatable by 180°, namely by in each case 90° during the down stroke and the up stroke.
9. Device according to claim 7, characterized in that the plate-like clamping segments are covered on one side with the elastic covering layer and in each working cycle can be tilted backwards and forwards by a given angle α.
10. Device according to claim 9, characterized in that the angle α is at least 90°.
11. Device according to one of the claims 1 to 8, characterized in that for driving the rotary clamping segments on the receiving frame (3) for the clamping tool is provided a motor driven gear controlled synchronously with the drive system of the automatic cutting press for the down or up stroke of the receiving frame (3) and connected with the rotary mounted clamping segments for the driving thereof.
12. Device according to claim 9 or 10, characterized in that for producing the tilting movement of the plate-like clamping segments provided on one side with the elastic covering layer a drive bringing about a reciprocating tilting movement in the machine cycle is provided.
13. Device according to one of the claims 1 to 4, characterized in that in a multipart construction of the clamping tool constructed as a flat element (16) mutually displaceable clamping segments are provided for the cyclic release of openings.
14. Device according to claim 1, characterized in that the clamping tool is provided with mechanical or pneumatic means for removing the broken away cuttings (6) from the surface of the flat element (16).
15. Device according to claim 14, characterized in that the clamping tool is constructed as a belt conveyor with an elastic covering layer, which can be raised and lowered cyclically and synchronously with the breaking away tools and with a conveying direction at right angles to the device transporting direction.
16. Device according to claim 14, characterized in that air nozzles are so arranged and cyclically subject to the compressed air that they blow off the broken away cuttings.
17. Device according to one of the preceding claims 1 and 5 to 16, characterized in that the clamping tool is constructed as a completely elastic or elastically mounted, one or multiple-part, flat element with a fixed, non-elastic surface.
18. Device according to one of the preceding claims 1 and 5 to 16, characterized in that the clamping tool is constructed as a one or multiple-part, flat element with a non-elastic surface, whereas the breaking away tools constructed as breaking away shafts are elastically mounted in the breaking away direction.
19. Device according to one or more of the preceding claims, characterized in that the matrix (11), breaking away tool and clamping tool are in each case located in a slide-in frame (1, 2, 3).
20. Clamping tool for a device for breaking away blank cuttings during the cutting out of cardboard in an automatic cutting press,

    - with a matrix (11), whose openings (12) are slightly larger than the cuttings (6) to be broken away,

    - and with cyclically vertically movable breaking away tools positioned above the matrix (11),

    - as well as with cyclically vertically movable clamping tools below the matrix (11) for gripping and separating the cuttings (6) in conjunction with the breaking away tools,
    characterized in that

    - the clamping tool is constructed as a flat element (16),

    - engaging over the openings (12) of the matrix (11) with its surface it can be pressed onto said matrix (11) and

    - is operatively connectable with the breaking away tools over the cuttings (6) for breaking away the latter.
21. Clamping tool according to claim 20, characterized in that it is further developed according to one or more of the claims 2 to 19.
22. Process for breaking away blank cuttings during the cutting out of cardboard in an automatic cutting press,

    - with a matrix (11), whose openings (12) are slightly larger than the cuttings (6) to be broken away,

    - and with cyclically vertically movable breaking away tools positioned above the matrix (11),

    - as well as with cyclically vertically movable clamping tools below the matrix (11) for gripping and separating the cuttings (6) in conjunction with the breaking away tools,
    characterized in that

    - the top surface of the cuttings (6) are engaged by the breaking away tools and the bottom surface by a clamping tool engaging over the openings (12) of the matrix (11) and constructed as a flat, one or multiple-part element (16) and

    - during the down stroke of the working cycle remains jammed between the breaking away tools moved down jointly with the element (16) and the surface of said element (16) and

    - for breaking away is transported downwards, released and discharged.
23. Process according to claim 22, characterized in that the jamming of the cuttings (6) between the breaking away tool and the clamping tool is only brought about during the down stroke of the working cycle and is optionally cancelled out before reaching the bottom dead centre for the immediate discharge of the cuttings (6).

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