HK1111971A - Back-edge braking system - Google Patents

Description

Rear edge brake system

Technical Field

The invention relates to a sheet processing machine with a sheet braking device and a method for braking a sheet to a stop state.

Prior Art

Machines for processing sheets conventionally have a sheet feeder, a plurality of sheet processing stations and a delivery. The uppermost sheet is separated from the stack of sheets in the sheet feeder and is transported to the transport system. The transport system transports the sheet through the processing station to the delivery device. One known transport system is an endless running gripper carriage. The gripper carriages each consist of a transverse bar on which grippers are arranged, by means of which grippers the sheet is gripped on its front edge, the ends of which grippers are fastened to lateral chain belts which guide the gripper carriages through the machine. For processing and delivery, the sheet must be braked to a stop. This is achieved, on the one hand, by braking the gripper carriage and, on the other hand, additionally by a further sheet brake. The machine for processing the sheets can be, for example, a sheet-fed printing press or, in particular, a sheet-fed die-cutting-embossing machine.

Cutting with a closed geometric cutting die is referred to as "die cutting" and may be circular, oval or polygonal as well as any type of imaginary shape. Practices such as punch die cutting, chamfering and index die cutting in post-press processing are in the field. The die cutting is performed towards the die cutting seat or towards the punch, partly also the cutting process (see post-press processing, training manuals for bookbinders, federal printing association, 1996, page 351 and below). Packaging materials made of paper, paperboard, cardboard or corrugated paper are primarily die cut to sheet size. Also, groove lines or plain embossing can additionally be produced in the useful part during the die-cutting process. This complex process necessitates that the sheets be individually die cut. Since the end product is a packaging which is extremely demanding in terms of technical and graphic implementation (for example for cosmetics, cigarettes, pharmaceuticals, foodstuffs, etc.), not only are special requirements placed on the packaging material itself, but also, for optimum results, the dies are required to have minimum tolerances and the die cutting machine is particularly accurate and reliable in operation. The platform die cutting machine best meets these requirements. In this case, the sheets printed and stacked on the pallet are fed to the die cutting machine. In this machine, the sheets to be diecut are aligned in a precisely coordinated manner in an alignment device, are taken up by a gripper carriage and are positioned precisely in a die-cutting device between a fixedly arranged lower table and an upper table which can be moved vertically by means of a toggle lever or eccentric drive.

Such a platform die cutting machine is known, for example, from DE 3044083 a 1. The two work stations are equipped with cutting and creasing dies or corresponding counter dies, by means of which useful parts are die-cut from the sheets which are guided through between the work stations in a clocked manner and at the same time the grooves required for the neat folding are pressed out. The waste material is mechanically removed in a subsequent breaking device by a breaking tool. Finally, depending on the machine equipment, the die-cut useful parts are separated in useful part separating devices provided for this purpose.

In both the severing station and the useful part separating station with delivery, the sheet must be braked from the transport speed to a standstill. Since sheets weakened by the preceding cut enter these stations at high speeds, the individual deceleration of the leading gripper bar can cause the trailing portion of the sheet to slip, so-called "bulge". This is to be prevented by an additional braking device acting on the sheet surface. The tensioned sheet can then be processed at a higher speed or laid down with edge accuracy.

Various types of sheet brakes are known from the prior art.

EP 1108671 a2 discloses a sheet braking system for a delivery of a sheet processing machine, having a cyclically operating braking belt. The braking belt has a suction zone that applies suction to the sheet to be braked. The braking belt undergoes periodic deceleration and acceleration phases, i.e. runs in a beat-to-beat fashion with the sheet transport. During the duration of the sheet deceleration phase, the braking portion of the braking band is covered by the sheet to be braked.

DE 4218421 a1 discloses a sheet guide in a delivery of a sheet-fed printing press. Two gripper systems are used: a leading edge gripper system and a trailing edge gripper system each having a sheet gripper for gripping an edge of a sheet. The simultaneous guidance of the sheet on its front and rear edges allows the sheet to be transported and braked without damage and reliably.

In a variant, pneumatic sheet brakes are used, as is known from DE 10259556 a 1. The brake is located directly adjacent to the sheet and provides a negative pressure which acts as a braking force on the sheet moving past the pneumatic sheet brake. The pneumatic sheet brake has the advantage over the mechanical sheet brake that the sheet surface is not damaged and thus marking can be avoided. The working principle of the pneumatic sheet brake is based on the venturi effect.

DE 69500514T 2 discloses a sheet braking device with brushes, for example. The brushes are oriented obliquely with respect to the sheet conveying direction and exert a braking force on the sheet by a light pressure. This has the disadvantage that marks can be formed on the sheet as a result.

DE 102004022235 a1 discloses a device for depositing sheets in a delivery of a sheet-fed printing press. The device has both a sheet brake acting in a force-locking manner over the entire sheet width and a receiving gripper and a suction bar in the rear region of the delivery. Since the sheet has to be gripped and released again at different times for optimal placement depending on the operating state or material properties, the suction bar is movable in the sheet transport direction. A problem with this sheet brake embodiment is that the suction strip is subject to greater wear due to its movability. Furthermore, it is problematic that such sheet brakes cannot be used in the processing stations of sheet-fed processing machines, since otherwise a collision of the processing tools with the suction bar would occur. However, the sheet brake must be adapted to the sheet format to ensure that the sheet brake acts on the sheet until the sheet stops.

Common to all sheet brake systems known from the prior art is that they are always located in the entry region to the processing station and to the delivery and are therefore mounted directly in front of the delivery surface or the processing tool. In practice, however, the length of the delivery and of the processing stations does not always correspond to the length of the currently running sheet. The sheet of small format cannot be braked to a stop by the sheet brake system, since the sheet is transported by the leading edge to a defined final position and is therefore no longer in the range of action of the sheet brake system. In order to still be able to brake the sheets until they stop, they must usually be forced from the front edge.

Disclosure of Invention

The object of the invention is to improve a sheet processing machine in such a way that sheets are coordinated precisely and protected independently of their format, and to provide a corresponding method.

According to the invention, a sheet processing machine for processing sheets of paper, cardboard or the like is proposed, comprising at least one processing station, a delivery device, a sheet transport system with endless gripper carriages which are driven by individually controllable linear drives, a machine control device and in each case one stationary braking device between an entry edge of the delivery device and a rear edge of a stack of sheets and/or one stationary braking device between an entry edge of the at least one sheet processing station and a rear edge of a tool of the processing station, wherein: the respective sheet is aligned in its stop position in the delivery and/or in its stop position in the at least one processing station with reference to its trailing edge, wherein the respective sheet is transported by the linearly driven gripper carriages of the sheet transport system up to a stop position depending on the sheet format, and the braking device acts on the respective sheet until the sheet stops.

According to the invention, a method for braking a sheet to a stop state in a sheet processing machine is also provided, characterized by the following steps: manually determining the specification of the page; inputting the sheet specification into a machine control; calculating, by means of a machine control device (15), a sheet stop position of the sheet in the delivery device and/or in the at least one processing station such that a sheet rear edge of the respective sheet directly overlaps a sheet stack rear edge or a rear edge of a tool of the processing station; the machine is operated, wherein the linear drive and the sheet brake of the sheet transport system are controlled by the machine control device in such a way that the sheet is always coordinated and precisely braked to its sheet stop position.

In the solution according to the invention, the sheet, in particular the sheet of small format, is stopped precisely by the defined position of the rear edge of the sheet.

In an advantageous embodiment, a sheet processing machine for processing sheets made of paper, cardboard and the like has at least one processing station, a delivery device and a sheet transport system with an endlessly operating gripper carriage. The sheet processing machine relates to a sheet punching and embossing machine, so that the processing stations can be embodied as a punching station, a severing station and a useful part separating station. The gripper carriages are driven by individually controllable linear drives. The processing station and the sheet transport system are controlled by a common machine control. The sheets are transported by the sheet transport system from the sheet feeder, i.e., from the rear end of the machine, in the sheet transport direction through the individual processing stations to the delivery, i.e., the front end of the machine.

The braking device is located between the inlet edge of the delivery device and the rear edge of the stack of sheets of the delivery stack. The entry edge of the delivery is one of the station boundaries of the delivery, specifically the edge of the delivery which the moved sheet first passes. The rear stack edge of the delivery stack is formed by the rear sheet edge of the laid-down sheet.

It is also possible for a brake device to be located between the entry edge of a processing station and the rear edge of the tool of a processing station. The entry edge of the processing station is one of the station boundaries of the processing station, specifically the edge of the processing station which is first passed by the moving sheet. The rear edge of the tool of the processing station is the edge of the tool which is first passed by the moving sheet. In order to process the sheet in one of the processing stations and to receive it in the delivery device, the sheet is braked from its transport speed to a stop. The sheet is processed or laid down in its stop position. This stop position of the sheet can be described by the position of the gripper carriage during the stop of the sheet.

The respective sheet is aligned with reference to its rear edge in its stop position in the delivery and/or in its stop position in the at least one processing station. This is achieved by: the respective sheet is conveyed by a linearly driven gripper carriage of the sheet conveying system to a specification-dependent stop position, and a braking device acts on the respective sheet until the sheet is stopped. This prevents "bulging" of the sheet.

In this case, the alignment in the sheet processing machine according to the invention advantageously allows the sheet rear edge of the respective sheet to overlap the sheet stack rear edge of the delivery stack or the rear edge of the tool of the processing station.

The sheet brake can be configured in various alternative embodiments: a sheet-fed sheet brake of the periodic type with a circulating suction belt, a trailing edge gripper system with a circulating trailing gripper for gripping a trailing edge of a sheet, a pneumatic sheet brake with a stationary suction device, a device with a brake brush or a non-periodic sheet brake with a permanently circulating suction belt.

A method for braking sheets, in particular small format sheets, until they are stopped in a sheet processing machine is also part of the invention. Sheets that do not have the maximum sheet length allowed by the size of the processing station are referred to as small format sheets. In a first method step, a sheet format is determined by a machine operator. In a second method step, he inputs the sheet format into the machine control. These two steps can also be combined by automation. In this case, the sheet format is determined by means of a sensor and sent to the machine control. In a third step, the machine control calculates the sheet stop position of each sheet in the delivery or processing station such that the sheet trailing edge of the respective sheet overlaps the sheet trailing edge of the delivery stack or the trailing edge of the tool of the processing station. That is, the sheet alignment is aligned on its rear edge. In a fourth step, the machine can be put into operation, in which the linear drive of the sheet transport system of the sheet processing machine and the sheet braking system directly in front of the processing station or delivery are controlled by the machine control device in such a way that the sheet is always configured to be braked precisely into its sheet stop position.

The method can be monitored by sensors known to the expert and the monitoring result fed back to the machine control.

Drawings

The invention will now be explained in more detail by means of an embodiment. Shown schematically in the drawings:

figure 1 shows a sheet processing machine according to the invention,

figure 2a shows a processing station with a sheet positioning and braking device according to the prior art,

figure 2b shows a view of a processing station with a sheet positioning and braking device according to the invention,

fig. 3 shows a view of a die-cutting station, a processing station and a delivery station with a sheet positioning and braking device according to the invention.

Detailed Description

The principle structure of a sheet punching and creasing machine 100 for punching, breaking and collecting sheets made of paper, cardboard and the like is shown in fig. 1. The sheet punching and embossing machine 100 has a sheet feeder 1, a punching station 2, a cutting station 3 and a delivery 4, which are supported and enclosed by a common machine housing 5.

The sheet 6 is separated from the stack by the sheet feeder 1 and fed, and is gripped at its front edge by a gripper carriage 8 with grippers, which is attached to a circulating chain 7, and is pulled intermittently through the various stations 2, 3 and 4 of the die-cutting and embossing machine 100.

The die-cutting station 2 consists of a lower table 9 and an upper table 10, the lower table 9 being fixedly supported in the machine frame and being provided with a counter plate facing the die-cutting knives. The upper table 10 is supported to be vertically movable up and down. In the entry region of the die-cutting station 2, a sheet brake 20 is provided, for example a clocked sheet brake with a circulating suction belt. The entry area for the die-cutting station is understood to be the area between the entry edge of the station and the rear edge of the die-cutting tool.

Gripper carriages 8 transport the sheets 6 from the die-cutting and creasing station 2 to a following breaking station 3, which is equipped with a breaking tool. In the breaking station 3, the unwanted waste material pieces are pushed down from the sheet 6 by means of a breaking tool, whereby the waste material pieces 11 fall into a container-like carriage 12 pushed under the station. In the entry region of the severing station 3, there is a sheet brake 20. The entry area for the breaking station is understood to be the area between the entry edge of the station and the rear edge of the breaking tool.

The sheets are transported from the separating station 3 to the delivery 4, where they are either simply laid down or the useful parts are separated simultaneously. In the inlet region of the delivery 4, a sheet brake 20 is provided. The delivery device 4 may also comprise a pallet 13 on which the individual sheets are stacked in the form of a stack 14 of sheets, so that after a certain stack height has been reached, the pallet can be removed from the area of the die cutting machine 100 together with the sheets 14 on the stack.

Fig. 2a shows a sheet 6 according to the prior art in its stop position in the processing stations 2, 3. The sheet 6 gripped by the gripper of the gripper carriage 8 with the linear drive is guided in the sheet transport direction F into the processing stations 2, 3. As soon as the front sheet edge BV reaches the catch 20, it acts on the sheet 6 until its rear sheet edge BH also passes the catch 20. In order to machine the sheet 6 between the upper mold 18 and the lower mold 19 between the lower table 9 and the upper table 10, the sheet 6 is aligned in a precisely coordinated manner on its sheet front edge BV according to the prior art. The front edge BV of the sheet coincides with the front edge AB of the tools of the processing station. A distance D results between the sheet trailing edge BH and the trailing edge EB of the tools of the processing station when the sheet 6 format is small. That is to say, the braking device 20 does not act on the sheet 6 until the sheet stops.

Fig. 2b shows the stop position according to the invention of a sheet 6 in the processing stations 2, 3. The sheet 6 entering in the sheet conveying direction F is braked by the braking device 20 as soon as it reaches the braking device. Since the sheet 6 is aligned on its sheet rear edge BH precisely in alignment with the rear edge EB of the tools of the processing station for processing by the lower table 9 and the upper table 10 or the upper die 18 and the lower die 19, the braking device 20 acts on the sheet 6 until it stops. In this case, the sheet rear edge BH and the rear edge EB of the tool of the processing station overlap directly one another.

Fig. 3 shows the stop position of the sheet 6 in its different processing stations 2, 3 and 4. As can be clearly seen in this figure, the rear edge EB of the tool of the processing station always directly overlaps the rear edge BH of the sheet in the processing stations 2, 3. In the delivery station 4, the sheet stack trailing edge EA also directly overlaps the sheet trailing edge BH. This ensures that the braking device 20 can act in the desired manner on the respective sheet 6 to be braked.

Reference mark

1 paper feeding device

2 die cutting station

3 disconnecting station

4 delivery station

5 machine housing

6 pages

7-sheet conveying system

Gripper carriage with linear drive

9 lower workbench

10 upper working table

11 pieces of waste material

12 trolley

13 supporting plate

14 delivery pile

15 control device

16 paper conveying table

18 upper die

19 lower die

20 braking device

BV front edge of page

BH sheet trailing edge

AB processing station tool front edge

Tool rear edge of EB processing station

EA paper pile rear edge

AA pile leading edge

Entrance edge of ES station

Egress edge of AS station

H stop position

F sheet conveying direction

Claims (8)

1. Sheet processing machine (100) for processing sheets of paper, cardboard and the like, having at least one processing station (2, 3), a delivery device (4), a sheet transport system (7) having endless gripper carriages (8) which are driven by linear drives which can be controlled individually, having a machine control device (15) and in each case one stationary braking device (20) between an entry Edge (ES) of the delivery device (4) and a rear Edge (EA) of a stack of sheets and/or between an entry Edge (ES) of the at least one sheet processing station (2, 3) and a rear Edge (EB) of a tool (9, 10, 18, 19) of the processing station (2, 3), characterized in that: the respective sheet (6) is aligned in its stop position in the delivery (4) and/or in its stop position in the at least one processing station (2, 3) with reference to its rear edge (BH), wherein the respective sheet (6) is transported by the linearly driven gripper carriage (8) of the sheet transport system (7) up to a stop position depending on the sheet format, and the braking device (20) acts on the respective sheet (6) until the sheet stops.

2. The sheet processing machine of claim 1, wherein: the sheet brake (20) is a clocked sheet brake with an endless suction belt.

3. The sheet processing machine of claim 1, wherein: the sheet brake (20) is a trailing edge gripper system having an endless trailing gripper for gripping a trailing edge (BH) of a sheet.

4. The sheet processing machine of claim 1, wherein: the sheet brake (20) is a pneumatic sheet brake with stationary suction.

5. The sheet processing machine of claim 1, wherein: the sheet brake (20) is a device having a brake brush.

6. The sheet processing machine of claim 1, wherein: the sheet brake (20) is a non-clocked sheet brake with a permanently circulating suction belt.

7. The sheet processing machine according to one of claims 1 to 6, characterized in that: the sheet processing machine (100) is a sheet punching and embossing machine.

8. Method for braking a sheet (6) in a sheet processing machine (100) until it is stopped, characterized by the following steps:

the specification of the sheet is determined manually,

the sheet format is input into a machine control device (15),

calculating, by means of a machine control device (15), a sheet stop position of the sheet in the delivery device (4) and/or in the at least one processing station (2, 3) such that a sheet trailing edge (BH) of the respective sheet (6) directly overlaps a sheet stack trailing Edge (EA) or a trailing Edge (EB) of a tool (9, 10, 8, 19) of the processing station (2, 3),

the machine (100) is operated, wherein the linear drive and the sheet brake (20) of the sheet transport system (7) are controlled by the machine control device (15) in such a way that the sheet (6) is always coordinately and precisely braked to its sheet stop position.