Brake Device For Braking and Depositing Blanks Extending Laminarly

Abstract

A braking device for braking and depositing two-dimensionally extending workpieces, particularly cardboard packaging, which are fed so as to be spaced apart from one another, the workpieces are fed to a braking roller whose circumferential speed is slower than the feed speed of the workpieces, and at least one cam presses a workpiece passing the braking roller against the braking roller at the end of the workpiece in the feed direction and reduces the speed of the workpiece.

Description

PRIORITY CLAIM

This is a U.S. national stage of Application No. PCT/DE2009/001606, filed on Nov. 16, 2009, which claims priority to German Application No: 10 2008 058 337.5, filed: Nov. 20, 2008, the contents of which are incorporated herein by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The invention is directed to a braking device for braking two-dimensionally extending workpieces, particularly such as blanks of cardboard packaging, or the like, of flexible materials that are fed so as to be spaced apart from one another and for depositing them on a stack.

2. Related Art

A variety of devices for processing two-dimensionally extending materials, e.g., printers and embossing machinery, cutting devices, and comparable production lines have high processing speeds and a high transporting speed for transporting the material to be processed or that has been processed. Speeds of about 10 m/second are quite common.

The problem arising at the end of a production line of this kind is that of braking and depositing the workpieces particularly made of flexible material such as blanks or the like in a manner that is not stressful to the material.

Braking the workpieces by having them run against stops is not gentle on the material. Further, it is seldom possible to deposit the workpieces in a neatly stacked manner. Usually, the braked workpieces then simply fall into a collecting bin. Braking systems of this kind for mostly robust workpieces are not suitable for flexible materials such as sheets that are to be deposited in stacks, because such materials are deformed when striking a stop. This results in an unacceptable, uneven depositing of the workpieces on a stack.

A so-called rear edge braking system is described in DE 20 2007 012 356 U1 particularly for braking sheets of paper, cardboard, or the like which resorts to an elaborate pneumatic sheet braking system.

SUMMARY OF THE INVENTION

One embodiment of the invention provides a braking device of the type mentioned above constructed in a mechanically simple manner to brake fed workpieces in a gentle manner and which can be adapted in a simple manner to a wide variety of workpieces.

The array of technical problems mentioned above is solved in a braking device for braking and depositing two-dimensionally extending workpieces, particularly cardboard packaging, which are fed so as to be spaced apart from one another in that the workpieces are fed to a braking roller whose circumferential speed is slower than the feed speed of the workpieces, and in that at least one cam presses a workpiece passing the braking roller against the braking roller at the end of the workpiece in the feed direction and reduces the speed of the workpiece.

The braking device according to one embodiment of the invention provides a number of advantages. In particular, it is best suited to cardboard packaging or other non-self-supporting workpieces comprising, e.g., foils, which would be deformed by running against a stop. This deformation is prevented in that the end of the workpiece is grasped between the cam and the braking roller. Also, a non-self-supporting, easily deformable workpiece such as cardboard or the like maintains an extended position, or the workpiece has the time to resume an extended position before being deposited on a stack.

Further, in one embodiment, the cam can project over a roller. This simple constructional solution allows the speed components comprising roller and braking roller to be adapted to one another simply by adjusting a drive. In particular, in this case the circumferential speed of the roller is adjusted in such a way that the cam executes a revolution in the time that it takes to feed a workpiece. Therefore, when the fed workpieces are advantageously uniformly spaced, it can be ensured in a simple manner that the cam always only engages the end of the workpiece in order to press the workpiece against the braking roller and therefore brake it.

The preferably rounded contact pressing surface of the cam pressing the workpiece against the braking roller and the surface of the braking roller can run one upon the other in the manner of the surfaces of a pair of rollers, there routinely being a difference in speed in the circumferential speeds of the contact pressing surface of the cam and the braking roller. However, the forces brought about in this way on the workpiece can be minimized through the selection of and shape of the cam surface so that the workpiece cannot be damaged by the braking process.

In one embodiment, the roller is arranged above the braking roller, and the axes of the roller and of the braking roller lie in a common plane transverse to the feed direction. These steps allow a simple bearing support of the two rollers and their drives in the manner of calender rolls.

Further, the horizontal arrangement results in a gap between the roller and the braking roller which, in case of a constant circumferential speed of the roller and, therefore, of the cam, is periodically opened and closed by the cam. The feed of the workpieces is carried out in a plane extending between the roller and the braking roller so that the workpiece enters the open gap and the end of the workpiece is only pressed down on the braking roller by the cam when the gap is closed. With flexible workpieces such as sheets of cardboard or the like, an upwardly directed deflection is brought about owing to the initially free entry of the workpiece into the gap between the roller and the braking roller and the downward movement of the end of the workpiece during braking.

It has proven to be advantageous when the cam and/or the roller are/is operationally exchangeable. This removes the difficulties in adapting to the material thickness of the workpiece because the height of the cam above the roller can be adjusted depending upon the material thickness of the workpiece. Further, the surface condition of the workpiece can be taken into account by the choice of material for the cam, for example, stainless steel, plastic, or rubber, so that the workpieces are pressed against carefully even when there is a speed difference in the circumferential speeds of the braking roller and cam. This can also be taken into account by the surface condition of the contact pressing surface, e.g., by a coating or texture, for example, scales, grooves, or the like.

Further, it has proven to be advantageous when the cam is displaceable transverse to the feed direction. In particular, the cam can be secured so as to be axially displaceable on the roller so that printed cardboard packaging, for example, can be grasped and braked outside the actual print area. In this way, the print image of cardboard packaging of this kind remains reliably unimpaired. Further, this step can take into account punched out portions for a carrying handle.

Further, in the braking device according to the invention the angular speed of the roller supporting the cam is adjustable. In this way, the time interval within which the open gap remains between the braking roller and the roller can be preset so that a workpiece can enter into this gap unimpeded. The cam first presses the end of the workpiece down against the braking roller at the end of the workpiece. This step takes into account different lengths of the workpieces.

Further, when the dimensions of workpieces change frequently or when the spacing between the workpieces varies, sensors can be provided to measure the length of and/or distances between workpieces in feed direction, and a control of the angular speed is adjusted in such a way that the cam presses each workpiece against the braking roller at the end of the workpiece. Accordingly, it is possible to adapt to different lengths of the workpieces in a simple manner, and nonuniformities in the process of feeding the workpieces can also be compensated without difficulty. The point of application of the cams on the workpieces can also be adjusted.

In braking devices of the type under discussion for braking and depositing two-dimensionally extending workpieces, the workpieces routinely become backed up in the braking zones. To remedy this problem, after running through the braking device according to the invention workpieces are fed in a falling motion to a storage, a pallet, or the like in a shingled manner but so as to be spaced one above the other. This is ensured in that the roller is followed in the feed direction by at least one guide belt revolving above the workpiece. This reliably prevents the workpiece from upward excursion because of deflection due to the free entry into the gap and due to the end of the workpiece being pressed down against the braking roller. Rather, the workpieces lying one over the other in a shingled manner are moved along at a distance from the guide belt and are deposited, e.g., on a pallet or in a storage in falling motion.

Cams and guide belts can be staggered transverse to the feed direction. In particular, when a central guide belt is arranged in the middle, this guide belt is enclosed by two cams simultaneously. Particularly unstable workpieces such as cardboard packaging or comparable sheets which routinely bend during the braking process are reliably guided and deposited in this way.

It is further provided in an advantageous manner that the circumferential speed of the guide belt approximately corresponds to, particularly is also equal to, the feed speed of the workpieces, so that the workpieces do not undergo any reduction in speed when entering the gap between the roller and braking roller, for example, when sheets contact the guide belt due to bending.

In a constructional embodiment, a driveshaft of a drive and a driveshaft of the guide belt can be connected to one another by a belt so as to obviate an independent drive of the guide belt. The idea in this case is, in particular, that the driving of the guide belt is carried out by a belt drive jointly with the driving of the conveyor devices such as conveyor belts, or the like, which feed the workpieces to the braking device.

In production lines for workpieces, particularly in-line production lines, the braking device mentioned above is arranged at the end. After stacking the workpieces, they can be transferred to a stack turning unit which then turns the stack and deposits it on a conveyor belt or other conveying device. Further, in order to increase capacity a points switch can be arranged upstream of two braking devices according to the invention. In so doing, the braking devices following the points switch are preferably arranged so as to be offset in height and a transfer device preferably transfers the stacked bundles from the braking devices to a stack turning unit. This makes it possible to construct a high-capacity production line in a space-saving manner.

BRIEF DESCRIPTION OF DRAWINGS

The invention will be described in more detail in the following with reference to drawings in which the embodiment examples are shown schematically. The drawings show:

FIG. 1 is an isometric diagram of a braking device according to the invention;

FIG. 2 is a side view the breaking device of FIG. 1;

FIG. 3 is a top view the breaking device of FIG. 1;

FIG. 4 is an enlarged view of a portion of the breaking device of FIG. 1; and

FIG. 5 is an illustration of the use of the braking device.

DETAILED DESCRIPTION OF DRAWINGS

FIG. 1 is an isometric diagram showing a braking device 1 according to one embodiment of the invention for braking and depositing two-dimensionally extending workpieces 4, preferably cardboard packaging which is, for example, printed, punched and singled in a production line 2, not shown in more detail, which are fed particularly in a uniformly spaced manner to the braking device at high speed, e.g., 500 m/min and with a high cycle rate of about 10 pieces/sec.

Workpieces 4 (shown in FIG. 4) of this kind which are braked by the braking device 1, are deposited, e.g., in a storage 3 so as to be stacked in an exact manner.

In the present embodiment example as shown in FIGS. 3 and 4, the workpieces 4 are fed to a braking roller 7 in the feed direction 8 indicated by the arrow on a rod linkage 5 of a conveyor belt 6. The braking roller 7 rotates according to the arrow 9 and has a belt drive 10 has a circumferential speed which is appreciably lower than the feed speed at which the sheets 4 are fed in the feed direction 8.

Another roller 11 is arranged above the braking roller 7, the axis 12 of the braking roller 7 being arranged in a plane transverse to the feed direction 8 with the axis 13 of the roller 11.

The feed of the workpieces 4 is carried out in a plane 22 of the gap between the roller 11 and the braking roller 7.

Two cams 14, 15 project above the roller 11 and, as is shown in FIGS. 3 and 4, press the end of a workpiece 4 passing the braking roller 7 downward against the braking roller 7 and accordingly reduce the speed of the workpiece 4.

The angular speed of the shaft 11 is adjusted in such a way that the cams 14, 15 always press the workpiece 4 against the braking roller 7 at the end of the workpiece 4, wherein a revolution of the cams 14, 15 lasts for the duration of the feed of a workpiece 4 taking into account the distance between the workpieces 4.

The cams 14, 15 or, as the case may be, the roller 11 in its entirety can be exchanged in operation and/or the cams can be displaceable transverse to the feed direction 8 so that it is possible to adapt to different workpieces 4 without difficulty. If the workpiece 4 is, e.g., a sheet with printing on its upper surface, the cams 14, 15 are adjusted in such a way that a workpiece 4 of this kind can be pressed at its end against the braking roller 7 on unprinted surfaces by the cams 14, 15 while passing the braking roller 7. This precludes damage to the print image on the upper side of the workpiece 4. Geometries of the workpieces 4, e.g., punched out portions, can also be taken into account in a corresponding manner.

Further, by the steps mentioned above, the preferably rounded contact pressing surface 16 can be adapted to a coating or surface texture on the workpieces 4 by a suitable choice of material for the cams 14, 15 for purposes of a careful pressing against the braking roller 7.

Further, in order to take into account different lengths of workpieces 4, the angular speed of the roller 11 is adjustable so that the interval in which the cams 14, 15 strike the braking roller 7 while enclosing a workpiece 4 is adjustable. This can be automated in that sensors, not shown in the drawing, can measure the length of workpieces and/or the distance between workpieces 4 in the feed direction 8, whereupon a control adjusts the angular speed of the shaft 11 in such a way that the cams 14, 15 press each workpiece 4 down against the braking roller 7 exactly at its end so as to be synchronized with the feed.

When the workpieces 4 are sheets which bend relatively easily, they will bend, as is shown in FIG. 4, when entering the free gap between the roller 11 and the braking roller 7 and also when braked and, after being released by the cams 14, 15, will queue until their front edge strikes a guide belt 17 revolving above the workpieces 4. Owing to the high cycle rate of braked workpieces 4, these workpieces 4 will lie one on top of the other so as to be spaced in a shingled manner as is shown and will be fed to the storage 3 by the guide belt 17 and deposited in a falling motion so as to be neatly stacked.

FIG. 3 further shows that the cams 14, 15 and the guide belt 17 are staggered; in this case, the guide belt 17 is arranged centrally between the cams 14, 15 simultaneously.

The circumferential speed of the guide belt 17 corresponds substantially, preferably exactly, to the feed speed of the workpieces 4 in feed direction 8 in front of the braking device 1. Accordingly, it is ensured that there will be no reduction in the speed of the workpiece 4 when the workpiece 4 bends as it freely enters the gap between the braking roller 7 and the roller 11 and braking and its front edge contacts the guide belt 17.

A driving of the guide belt 17 can be carried out in a simple manner by a belt 18 which is driven by an electric-motor drive 19 of the feed devices of the workpieces 4 along with the conveyor belt 6. The braking roller 7 and the roller 11 each have their own drive 20, 21 so that the circumferential speeds of the two rollers 7, 11 can be adjusted independently from one another in a simple manner.

FIG. 5 shows a transporting device 23 on the right-hand side, e.g., two conveyor belts enclosing a workpiece, at the end of a production line, not shown in more detail, for two-dimensionally extending workpieces. These two-dimensionally extending workpieces, such as cardboard packaging, which are fed from the right-hand side with respect to FIG. 5 so as to be spaced apart stop on a points switch 24 at the end of the transporting device 23, two braking devices 25, 26 according to the invention being served by this points switch 24.

The braking devices 25, 26 deposit the workpieces in a braked manner as stacks 27, 28. This stacking of the workpieces is carried out so as to be offset in time so that one of the stacks 27, 28, when finished, can be transferred to a vertically adjustable transfer device 31 by transporting devices 29, 30. This transfer device 31, which is provided with a vertically adjustable conveying device 32 shown in two positions in FIG. 5, transfers stacks 33 to a stack turning unit 34 which, after the received stacks have been turned, deposits the stacks, for example, on a transporting device 35 for shipment.

Thus, while there have shown and described and pointed out fundamental novel features of the invention as applied to a preferred embodiment thereof, it will be understood that various omissions and substitutions and changes in the form and details of the devices illustrated, and in their operation, may be made by those skilled in the art without departing from the spirit of the invention. For example, it is expressly intended that all combinations of those elements and/or method steps which perform substantially the same function in substantially the same way to achieve the same results are within the scope of the invention. Moreover, it should be recognized that structures and/or elements and/or method steps shown and/or described in connection with any disclosed form or embodiment of the invention may be incorporated in any other disclosed or described or suggested form or embodiment as a general matter of design choice. It is the intention, therefore, to be limited only as indicated by the scope of the claims appended hereto.

Claims

1-17. (canceled)

18. A braking device for braking and depositing two-dimensionally extending workpieces that are fed spaced apart from one another, comprising:

a braking roller to which the workpieces are fed, whose circumferential speed is slower than a feed speed of the workpieces; and

at least one cam configured to press a respective workpiece passing the braking roller against the braking roller at an end of the workpiece in a feed direction to reduce the speed of the workpiece.

19. The braking device according to claim 18, wherein the at least one cam projects from a roller.

20. The braking device according to claim 19, wherein the at least one cam is configured to execute one revolution in a time that it takes to feed a workpiece.

21. The braking device according to claim 19, wherein the roller is arranged vertically above the braking roller, and in that respective axes of the roller and of the braking roller are in a common plane transverse to the feed direction.

22. The braking device according to claim 21, wherein the feed of the workpieces is carried out in a plane extending between the roller and the braking roller.

23. The braking device according to claim 18, wherein one or more of the at least one cam and the roller is operationally exchangeable with the at least one cam.

24. The braking device according to claim 18, wherein the cam is displaceable transverse to the feed direction.

25. The braking device according to claim 18, wherein an angular speed of the roller supporting the cam is adjustable.

26. The braking device according to claim 25, further comprising at least one sensor configured to at least one of measure the length of and distance between workpieces in the feed direction, and in that the angular speed of the roller is adjusted such that the cam presses each workpiece against the braking roller at the end of the workpiece.

27. The braking device according to claim 19, wherein the roller is followed in the feed direction by at least one guide belt vertically above the workpiece.

28. The braking device according to claim 27, wherein the cam and the at least one guide belt are staggered transverse to the feed direction.

29. The braking device according to claim 27, wherein a circumferential speed of the at least one guide belt substantially corresponds to the feed speed of the workpieces.

30. The braking device according to claim 27, wherein a driveshaft of a drive and a driveshaft of the guide belt are connected by a belt.

31. A production line for workpieces, comprising at least one braking device provided at an end of the production line, the braking device comprising:

a braking roller to which the workpieces are fed, whose circumferential speed is slower than a feed speed of the workpieces; and

at least one cam configured to press a respective workpiece passing the braking roller against the braking roller at an end of the workpiece in a feed direction to reduce the speed of the workpiece.

32. The production line according to claim 31, further comprising a stack turning unit arranged downstream of the braking device.

33. The production line according to claim 31, further comprising a points switch arranged upstream of two braking devices.

34. The production line according to claim 33, wherein the two braking devices following the points switch are arranged so as to be offset in vertical height, and in that a transfer device transfers the stacked bundles from the braking devices to a stack turning unit.

35. The braking device according to claim 18, wherein the workpieces are cardboard packaging.