EP0204019A1 - Device for applying a web to a support - Google Patents

Abstract

Device for attaching a tape (70) to a support, especially a tear- open tape to corrugated cardboard, cardboard, paper or the like, which is transported at a predetermined speed, with a stand, attachment means arranged in the stand for selectively applying the tape to the support, at least one supply roll (20) which is mounted rotatably in the stand and from which the tape is fed to the attachment means, and a control device for controlling the attachment means. A controllable drive device can be selectively coupled to the roll which is assigned a movable deflecting roller (42) connected to an adjusting device. The roll can be selectively coupled to a controllable braking device (31, 32), and the control device so activates the adjusting device, approximately simultaneously with an activation of the drive for accelerating the roll or with the activation of the braking device for decelerating the roll, that the deflecting roller (42) lengthens the path of the tape (70) to the attachment means.

Description

The invention relates to a device for applying a tape to a base, in particular a tear tape on corrugated cardboard, cardboard, paper or the like, which is transported at a predetermined speed, with a frame, application means arranged in the frame for optional application of the tape against the Base, at least one supply roll rotatably mounted in the frame, from which the tape is fed to the application means, and a control device for controlling the application means.

It is known to tape corrugated cardboard in front of or behind a cutting and creasing device with a tear tape.

The tear tape is usually self-adhesive on one side and is unwound from a supply roll. This is done in that a pressure roller presses the tape against the running corrugated cardboard web after the previous signal, so that the corrugated cardboard web automatically unwinds the tape from the supply roll. At the end of this process or when changing the format, it is necessary to cut the tape. It has already been proposed to arrange a cutting device near the pressure roller and to assign a pressure-retaining device to the pressure roller, which optionally holds or releases the tape (European patent application 85102379.6). In the event of a format change, for example, the cutting device cuts the tear tape, for example with the aid of a translationally operated knife. At the same time or somewhat earlier, the holding device grips the tape and temporarily holds it. If a band is to be applied again, the holding device lets go of the band so that it is placed against the web in the usual way with the aid of the pressure roller.

The corrugated cardboard web is known to run through the plant at high speeds. At the start of the application of the tape, it is accelerated to the speed of the corrugated cardboard web. Unless special precautions are taken, the supply or unwinding roll must be brought to a rotational speed which corresponds to the web speed. Especially when the roll is full, it has a not inconsiderable moment of inertia. This gives the tape great tensile stress and there is a risk of the tape tearing. Conversely, when the tape is cut, the unwinding roller tends to continue rotating due to its inertia. If no precautions are taken, a more or less length of tape will unwind, which is understandably highly undesirable as this can lead to malfunctions. The invention has for its object to provide a device for applying a tape to a base with which a tape can be applied in a flawless manner even at higher speeds of the base.

This object is achieved in that a controllable drive device can be optionally coupled to the roller, the roller is assigned a movable deflection roller which is connected to an adjusting device, the roller can optionally be coupled to a controllable braking device and the control device approximately simultaneously with a control of the drive for accelerating the roller or with the control of the braking device for decelerating the roller drives the adjusting device so that the deflection roller the path of Tape extended to the application agent.

The device according to the invention provides a drive device which, when coupled to the roller, rotates it and accelerates it to a specific speed value. The signal for the activation of the drive device comes from the control device which also controls the application means, i.e. for example the pressure roller for pressing the tape against the base, the knife for cutting the tape and possibly the holding device for holding the tape shortly before and after being cut by the knife. If the actuating device for the pressure roller receives the control command to put the tape against the support, then the drive device can be switched on simultaneously or shortly beforehand in order to drive the roller and accelerate it to a predetermined speed. The roller is preferably driven somewhat earlier than the actuation of the pressure roller, for example 200 to 500 milliseconds, so that the roller has already reached a speed which approximately corresponds to the speed of the support in order to keep the tension as low as possible. After the acceleration process, the drive device is switched off again and the unwinding roll should rotate freely if possible so that the support can unwind the tape automatically from the roll.

Accelerating the roll before unwinding through the driven pad creates a unwound length that is not yet used up. The adjusting device ensures that the deflecting roller increases the deflecting path and thereby takes up the band length which is initially not required. After the unwinding roller has accelerated to the operating unwinding speed, the deflection roller can return to its starting position. This is preferably done gradually so as not to get any slack in the band.

The braking device of the device according to the invention is actuated when the application of the tape to the base is to be ended. As already mentioned above, the application is ended by cutting off the tape with a knife, the adjusting device for the knife receiving its control command from a control device. At the same time, the control command for the braking device can be generated. This brakes the unwinding roll. At the same time, the deflection roller is adjusted again to increase the deflection path. In this way, the deflection roller catches the excess tape that has still been unwound. Shortly afterwards, the deflection roller returns to its normal position, for example 100 to 300 milliseconds after the start of braking.

With the aid of the device according to the invention, it is possible to apply a tape even at very high transport speeds of the base. Inadmissible tape tensions and excess tape lengths are avoided. With the aid of the device according to the invention, it is also possible to provide a tape for relatively short documents, for example cardboard cuts, which are transported at high speed.

According to one embodiment of the invention, the drive device can be connected to the roller via a controllable coupling. With the help of the controllable clutch, which according to a further embodiment of the invention is an electromagnetically or pneumatically actuable friction clutch, the drive time for the winding roll can be set precisely.

There are various options for a transmission between the drive device and the take-up reel. According to the invention, a particularly simple one is that a drive wheel can be coupled to the roller, a wrap-around tension means wraps around the drive wheel and a deflection wheel, and the drive device drives the deflection wheel or wrap-around tension means. An endless chain is preferably used, which is guided around the driving wheel and around the steering wheel. According to a further embodiment, the drive device is a Adjusting cylinder, which is coupled to the traction mechanism. A relatively long-stroke adjusting cylinder is sufficient to accelerate the unwinding roll to a desired rotational speed. According to a further embodiment of the invention, the adjusting cylinder is assigned end position transmitters which give end position signals to the control device. The end position sensors ensure that the pressure medium supply is interrupted when the end position is reached. They can also be used to generate a control command for the clutch. If the adjusting cylinder has reached its corresponding end position during the acceleration process of the winding roller, the clutch is separated so that the unwinding roller can now rotate freely.

The deflection roller can be movably mounted in different ways. A particularly preferred embodiment of the invention provides that the deflection roller is freely rotatably mounted on a swivel arm. The axis of rotation can coincide with the axis of rotation of the unwinding roll. The adjusting device for the swivel arm can be formed by an adjusting cylinder which holds the deflection roller in the normal operating position during normal operation and adjusts the deflection roller in a catch position when the roller is accelerating or decelerating. The adjusting cylinder can interact with a tension spring that is tensioned in the normal position. In the normal In the operating position, therefore, the adjusting cylinder is pressurized to hold the deflection roller, for example on the swivel arm, against the spring tension in the normal operating position. In the event of acceleration or deceleration of the unwinding roller, the adjustment cylinder can be relieved, as a result of which the spring moves the deflection roller into the catch position. The extent of the adjustment depends on the tensile force acting on the pulley. The gear between the adjusting cylinder and swivel arm can also be formed by a chain drive. An end position transmitter can also be assigned to the second adjustment cylinder in order to send a signal to the control device when the adjustment cylinder has reached its normal operating position.

If a friction clutch is used, it is advantageous to use it as a braking device. However, it can also be advantageous to provide an additional brake, for example to connect a brake disc to the roller that interacts with a brake cylinder. The brake disc can also serve as a flywheel to avoid abrupt changes in speed or vibrations of the unwinding roller.

As already mentioned above, the signal for accelerating the unwinding roll is given by the control device, which receives a corresponding start signal from another signal generator. In the device according to the invention, it is also possible to derive the start signal for the acceleration from the device according to the invention itself. For this purpose, according to a further embodiment of the invention, a deflection tension sensor is assigned to the deflection roller, which gives a tension signal to the control device and the control device actuates the drive device when the application pressure reaches an upper limit value and actuates the brake device when the application voltage reaches a lower limit value. The placement of the tape on a support is noticeable by a tensile stress in the tape, which is detected in this way. It then triggers the acceleration of the take-up roll. Conversely, cutting off the tape leads to a reduction in the tension, which is detected in a corresponding manner and leads to braking of the unwinding roll. The tension measuring transducers can be formed by a pressure transducer which is assigned to the second adjusting cylinder for the deflection roller.

• Fig. 1 zeigt schematisch in Seitenansicht, teilweise im Schnitt die Vorrichtung nach der Erfindung.
• Fig. 2 zeigt einen Schnitt durch die Darstellung nach .Fig. 1 entlang der Linie 2-2.
• Fig. 3 zeigt eine Draufsicht der Vorrichtung nach Fig. 1 unter Weglassung des Schwenkarms.
• Fig. 4 zeigt schematisch Teile der Vorrichtung nach den Figuren 1 bis 3 mit einem Steuerschema.

The invention is explained in more detail below with reference to drawings.

• Fig. 1 shows schematically in side view, partly in section, the device according to the invention.
• Fig. 2 shows a section through the representation according to. 1 along line 2-2.
• FIG. 3 shows a top view of the device according to FIG. 1 with the swivel arm omitted.
• Fig. 4 shows schematically parts of the device according to Figures 1 to 3 with a control scheme.

Before going into the details shown in the drawings, it should be stated that each of the features described is of importance for the invention, either individually or in conjunction with features of the claims.

A frame 10 with a peripheral edge 11 is connected to a frame, not shown. An axis 12 is fixedly connected to the plate 10 at 13 in a manner not described in detail. A bushing 16 is rotatably mounted on the axis 12 by means of ball bearings 14, 15. A compression bushing 17, which has an inner circumferential recess 18, is seated in a rotationally fixed manner on the bushing 16. An unwinding roll 20 has a winding cylinder 21, which is on the press bush 17 is slidable. It carries wound strip material 22. The axis 12 has an axial channel which is connected at one end at 23 to a compressed air connection. Via a rotatable line coupling 24 and a line 25, the pressure space 26 formed by the recess 18 can optionally be acted upon by compressed air or atmospheric pressure. When pressurized, the press bushing 17 expands somewhat radially and thereby clamps the winding cylinder 21 tightly. However, this principle is known per se and is not the subject of the invention.

The bearing bush 16 has at the right end a radial flange 27 to which a flywheel 28 is screwed with the aid of screws 29. The disc has the radial extent of the winding roller in its full state. It is intended to compensate for the different moment of inertia as a function of the filling state of the unwinding roll 20.

A clutch disc 31 is fixedly connected to the radial flange 27 with the aid of screws 30. A counter disc 32 is connected to a retaining ring 33 by means of screws 34, which is rotatably seated on the axis 12 via a ball bearing 35. On the other side of the bearing ring 33, a chain wheel 36 is attached by means of screws 37. A bushing 38 is seated with the aid of two ball bearings 39 rotatable on the axis 12. Radially projecting from the bush 38, a swivel arm 40 is welded on. It is connected at the outer end to a bearing pin 41 which runs parallel to the axis 12 and on which a deflection roller is freely rotatably mounted at a short distance from the unwinding roller 20.

A sprocket 43 is attached to the right end face of the bush 38 by means of screws 44.

From Fig. 1 it can be seen that the plate 10 is elongated in the horizontal direction. It is used to support two deflection sprockets 45, 46 at a distance from the sprockets 36 and 43 (Fig. 2). Drive chains 47, 48 are wrapped around the chain wheels or deflection wheels (FIGS. 1 and 3). A first adjusting cylinder 50 is attached to plate 10 at 51. Its piston rod 52 has at the end a connecting piece 53 which is connected to an arm 54 which is returned parallel to the piston rod 52. At 55, the free end of arm 54 is connected to drive chain 48. The diameter of the chain wheel 36 and the associated deflection wheel 46 is such that the chain course lies in the same direction as the extension of the arm 54 or the direction of adjustment of the adjusting cylinder 50. In Fig. 1, the adjusting cylinder 50 is shown in the fully extended position. The adjusting cylinder 50 is actuated and the piston with the piston rod 52 retracted, the arm 54 pulls the chain 48 counterclockwise and drives the sprocket 33 also counterclockwise.

A further adjusting cylinder 56 is arranged above the adjusting cylinder 50 and further to the front of the plate 10. Its piston rod 57 runs parallel to the connecting line of the centers of the two chain wheels 43, 45. At the end of the piston rod 57, a cross piece 58 is attached, to which an arm 59 is fastened, which runs below the piston rod 57 and parallel at a distance from it. At the end of the arm 59, a guide member 60 is fastened which slidably sits on a guide rod 61 which extends parallel to the adjusting cylinder 56 or to the piston rod 57 at a distance from the latter. Arranged around the guide rod 61 is a tension spring 62 which is supported at the left end on an abutment 63, to which the guide rod 61 is also connected. The other end of the spring 62 is attached to the guide piece 60.

The guide piece 60 is also connected at 64 to the chain 47. In Fig. 4, the functional parts shown in Figures 1 to 3, insofar as they are important for the invention, are shown schematically. For reasons of clarity, the chain drives are shown separately, as is the arrangement of a clutch to actuate the unwinding roller 20. From FIG. 4 it can be seen that the adjusting cylinder 50 is assigned two end position sensors 61, 62. An end position sensor 63 is assigned to the adjusting cylinder 56. A pressure transmitter 64 is also assigned to the adjusting cylinder 56.

All actuatable or controllable functional parts are operatively connected to a control device 60. This is indicated by corresponding lines of action. The control device also serves to control the application means, not shown, as indicated by the action lines at 65.

The device shown works as follows.

In the idle state, ie when the take-up reel 10 is immovable, the adjusting cylinder 50 has the position indicated in FIG. 4 or FIG. 1 with the piston rod 52 fully extended. The adjusting cylinder 56 also has the position shown in FIG. 4 with the piston rod 57 almost completely extended. Da the spring 62 is a tension spring, the cylinder is acted upon by a pressure medium, for example compressed air. The spring 62 is tensioned until the piston reaches the end stop. This position corresponds to the position of the swivel arm 40 almost in the twelve-guide position. The friction clutch 31, 32 is in one gripped what is done by a corresponding actuation via the control device 60. The beginning of the tape on the unwinding roll 20 is guided to the application means and can be held there mechanically, pneumatically, etc. by suitable means.

If the control command now comes to apply the tape to a substrate transported at a certain speed, for example a corrugated cardboard web, the application means receive a corresponding control command so that, for example, the pressure roller presses the tape against the substrate while the holding means release the tape. About 100 to 300 milliseconds before the band is pressed against the support, the adjusting cylinder 50 receives pressure and thereby moves the piston rod 52 inwards. As a result, the chain 46 is driven counterclockwise. Accordingly, the unwinding roller 20 is rotated counterclockwise. The goal here is to accelerate the rotational speed of the unwinding roller 20 to the speed of the pad. Simultaneously with the actuation of the adjusting cylinder 50, the adjusting cylinder 56 is vented. The spring 62 pulls the piston rod 57 to the left into the cylinder 56. As a result, the chain 57 is also driven counterclockwise. The swing arm 40 is also opposed pivoted clockwise. The extent of the pivoting, however, depends on the tension of the belt 70 (shown in broken lines), which is guided by the roller clockwise (according to FIG. 4) around the deflection roller 42. Since a certain length of tape is unwound with the aid of the adjusting cylinder 50 at a relatively strong acceleration of the unwinding roller 20 before it is pulled off by being placed on the support, the swivel arm 40 is pivoted into the position shown in dashed lines (five or six o'clock position). With the help of the swivel arm 40 and the deflecting roller 42, the length of the released tape is therefore taken up, so that the entire tape remains under tension. If the piston of the adjusting cylinder 50 is completely retracted, this is reported to the control device 60 by the position transmitter 62, for example a reed contact. This disconnects the clutch 31, 32, and the unwinding roller 20 can rotate freely. The tape 70 is now unwound from the roll 20 by the tensile force of the base. The adjusting cylinder 56 is then pressurized again so that the piston and thus the piston rod 57 can move into the position shown in FIG. 4. The position transmitter 63, for example a reed contact, reports the position assumed. This retraction of the adjusting cylinder 55 takes place slowly, which is not least caused by the spring 62.

The position of the arm 40 shown in Fig. 1 is arbitrary. If necessary, the arm can also assume other positions in the normal position, e.g. the dash-dotted line in the two o'clock position of the deflection roller 42.

If the application of the tape is ended, a corresponding control signal is given by the control device 60 to a knife which cuts the tape. The clutch 31, 32 receives a control signal from the control device 60 and engages. Due to the existing inertia, however, the unwinding roll 20 cannot come to a standstill immediately, but rotates further by a certain angle. In order to catch the material being unwound, the adjusting cylinder 56 is again vented and the spring 62 pivots the swivel arm 40 again counterclockwise, to the extent that there is excess tape length. After 100 to 300 milliseconds after the start, the adjusting cylinder 56 is pressurized again. The swivel arm 40 therefore returns to the twelve-drive position shown in FIG. 4. The clutch 31, 32 is released again. The piston rod 52 of the adjusting cylinder 50 is then returned to the position shown in FIG. 4 pulled out. The chain 48 moves clockwise. The excess strip material is wound up again on the unwind roll 20. When the adjusting piston has reached the end position, as determined by the position transmitter 61, the compressed air is switched off. Furthermore, the clutch 31, 32 is engaged again. A new work cycle can then begin.

The braking process described occurs in that the clutch 31, 32 can also be regarded as a friction brake. It goes without saying that an additional braking device can be used, for example a brake cylinder which interacts with the flywheel 28 (FIGS. 2 and 3).

It is also possible to use the pressure transmitter 64 on the adjusting cylinder 56 as a measurement transmitter for the tension on the belt 70. An increase in the pressure, for example when accelerating, of the tape to be unwound can be detected by the control device 60 and used in an actuation signal for the adjusting cylinder 50 in order to accelerate the unwinding roller 20 so that it provides the tape length sufficiently quickly. Conversely, a drop in pressure in the adjusting cylinder indicates a decrease in the band tension, which takes place, for example, by cutting off the band. From this, the control device 60 can derive a brake signal lead, for example, for actuating the friction clutch 31, 32. Finally, with the help of the pressure sensor 64 and the supply or discharge of pressure in the actuating cylinder 56 on the other side of the piston, a targeted control or regulation of the tension of the band 70 can be obtained.

Claims (18)

1. Apparatus for applying a tape to a base, in particular a tear tape on corrugated cardboard, cardboard, paper or the like, which is transported at a predetermined speed, with a frame, application means arranged in the frame for optional application of the tape against the base, at least one in the frame rotatably mounted supply roll, from which the tape is fed to the application means, and a control device for controlling the application means, characterized in that with the roller (20) a controllable drive device (50) can be optionally coupled, the roller (20) a movable Deflection roller (42) is assigned, which is connected to an adjusting device (56), the roller (20) can be optionally coupled to a controllable braking device (31, 32) and the control device (60) approximately simultaneously with a control of the drive (50) to accelerate the roller (20) or with the control of the braking device (31, 32) for Ver delay of the roller (20) controls the adjusting device (56) so that the deflecting roller (42) extends the path of the belt (70) to the application means. 2. Device according to claim 1, characterized in that the drive device (50) via a controllable coupling (31, 32) with the roller (20) can be connected. 3. Apparatus according to claim 2, characterized in that the clutch (31, 32) is an electromagnetically or pneumatically actuated friction clutch. 4. Device according to one of claims 1 to 3, characterized in that a drive wheel (36) with the roller (20) can be coupled, a wrap (48) wraps around the drive wheel (36) and a deflection wheel (46) and the drive device ( 50) drives the deflection wheel (46) or belt tensioning means (48). 5. The device according to claim 4, characterized in that an endless chain (48) around the drive wheel (36) and deflection wheel (46) is guided. 6. The device according to claim 4 or 5, characterized in that a first adjusting cylinder (50) with the traction means (48) is coupled. 7. The device according to claim 6, characterized in that the adjusting cylinder (50) end position transmitter (61, 62) are assigned, which give end position signals to the control device (60). 8. Device according to one of claims 1 to 7, characterized in that the deflection roller (42) on a swivel arm (40) is freely rotatable. 9. Device according to one of claims 1 to 8, characterized in that the adjusting device contains an adjusting cylinder (56) which holds the deflection roller (42) in the normal operating position during normal operation and the acceleration roller (42) upon acceleration or deceleration of the roller (20) ) in a catch position. 10. The device according to claim 9, characterized in that the adjusting cylinder (56) cooperates with a tension spring (62) which is tensioned in the normal position. 11. Device according to one of claims 8 to 11, characterized in that a drive wheel (43) is connected to the swivel arm (40) coaxially to the pivot axis, an endless traction means (47) around the drive wheel (43) and a deflection wheel (45) looped around and the adjusting device (56) engages the traction means (47). 12. The apparatus of claim 9 and 11, characterized in that the adjusting cylinder (56) engages on a chain (47). 13. Device according to one of claims 9 to 12, characterized in that the normal operating position of the adjusting cylinder (56) is assigned an end position transmitter (63) which gives a signal to the control device (60). 14. Device according to one of claims 3 to 13, characterized in that the braking device is formed by the friction clutch (31, 32). 15. The device according to one of claims 1 to 14, characterized in that with the roller (20) a disc (28) is coupled with which a brake cylinder cooperates. 16. The apparatus according to claim 15, characterized in that the disc (28) is designed as a flywheel. 17. The device according to one of claims 1 to 16, characterized in that the deflecting roller (42) is assigned a tension measuring transducer (64) which is a train voltage signal to the control device (60) and the control device (60) actuates the drive device (50) when the tension reaches an upper limit value and actuates the braking device (31, 32) when the tension voltage reaches a lower limit value. 18. The apparatus of claim 9 and 17, characterized in that a pressure transducer (64) assigned to the second adjusting cylinder (56) measures the tensile stress.

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