GB1562006A - Device for butt-jointed tape sealing of flat objects - Google Patents

Description

(54) DEVICE FOR BTT-JOINTED TAPE SEALING OF FLAT OBJECTS (71) We, NEUBRONNER KG of Neubronnerstrasse, 6370 Oberursel/TS, Federal Republic of Germany; a German company do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement: The present invention relates to a device for manufacturing a butt-jointed tape seal on packages, blank cuts or webs or sheets of paper, cardboard, plastics material, wood and, especially, plastics coated cardboard materials.

The invention finds particular application in the butt-jointed tape sealing of the "factory seal" of box blank cuts.

It is known to use a device for buttjointed tape sealing of the "factory seal" of box blank cuts having a support for mounting a supply roll holding a continuous length of adhesive tape and tape roller for pressing against the cut tape length after activation of the adhesive layer of the tape, wherein between the support for the supply roll and the tape roller a device for heating the adhesive layer of the tape is provided.

However, it has been found, that with this device, the possible advantages, especially with regard to the advance speed respectively the production rate, cannot be achieved to a sufficient extent. Also, with the presently known sealing machines the requirements regarding the accuracy of the removal of the tape from the supply roll and the accuracy of the tape cutting caused by the increase of the production rate cannot be met.

It is an object of the present invention to at least minimize the disadvantages referred to above.

According to the present invention there is provided a device for manufacturing a butt-jointed tape seal on flat objects such as packages, blank cuts, or webs or sheets of paper, cardboard, plastics material, wood and plastics coated cardboard materials, by means of adhesive tape, substantially comprising a supply roll for the adhesive tape a cutting device for cutting off tape lengths needed for the tape sealing, as well as a transporting device for conveying the tape to an activating means provided with a heater for heating the adhesive layer of the tape length, means for advancing the objects along a travel path, wherein a light barrier is disposed in the path of the advancing object said light barrier acting on two counters, a first one of said counters being operatively coupled with a drive for drawing off tape from said supply roll to start the advance movement of the tape, and the second one of said counters is operatively coupled with the tape advance drive for termination of the tape advance movement and also is operatively coupled with said tape cutting device for starting the tape cutting action.

The term "light barrier" as used throughout the specification and claims is used in its normal connotation as meaning the combination of a light emitting device and a sensor.

In an advantageous embodiment, the counters are formed by a light source/light receiver assembly with a continuously rotating toothed disk disposed between the light source and the light receiver, as well as two series connected adjustable pulse counters, the inputs of both counters being coupled to said light receiver and the counters being intercoupled and coupled to said light barrier, so that the counting in said first pulse counter is started when the light beam in said light barrier is interrupted and the counting in said second pulse counter is started when a preset count is reached in the first pulse counter.

In a suitable embodiment the drive for the tape advance movement and the drive for the cutting knife in said cutting device are supplied by means of a respective solenoid actuated combination of a coupling and a brake.

In a further advantageous embodiment of the invention a disk is disposed on the drive shaft for the cutting knife and is provided with a single slit and cooperates with a light barrier transmitter for generating pulses stopping said tape cutting knife through a solenoid brake.

In a further embodiment of the device according to the invention which contains a hot air activating system, the activating system is formed by an air nozzle in which a heater cartridge is disposed, and a drum revolving on a shaft is disposed in the region of the air jet of said air nozzle and has a perforated shell or periphery, wherein the interior space of said drum is subdivided into a chamber facing towards said air nozzle and a chamber facing away from said air nozzle, and said chamber facing the air nozzle is connected to a control valve, for example in the form of a control clappet, adapted to open the air path through the nozzle during the working cycle and to close the air path through said air nozzle during the idle cycle.

The present invention will be further illustrated, by way of example, with reference to the accompanying drawings, in which: Figure 1 shows, in a somewhat schematic representation, a device for tape sealing the factory seal of box blank cuts with an activation by means of a hot air nozzle, which is suited with the tape control in accordance with the invention.

Figure 1A shows a plan view of a box blank cut in the position in which it is advanced into the device of Figure 1.

Figure 2 shows an enlarged, somewhat schematic representation of the hot air activating system of Figure 1 and additional details of the tape control.

Figure 3 is a view of the control panel of the device of the Figure 1 and 2.

Referring to Figure 1 of the drawings, there is illustrated a device with hot air activation for tape sealing of the factory seal of a box blank cut. The device essentially consists of a supply roll 20 for storing the adhesive tape 21 until it is drawn off to be used for tape sealing, the tape advance roller 22 together with its drive means (not shown) and a retractable counter roller 22a as well as a cutting device 23, known per se, and a roller conveyor means 24 for moving the box blank cuts 52 on which the factory seal is to be provided by means of buttjointed tape sealing of the appropriate edges of the box blank. The activating system comprises a hot air blower containing an air nozzle 26 in the interior of which a heater cartridge 27 and a drum 29 rotating around a shaft 28 and provided with a perforated peripheral surface 29a.The interior space of the drum 29 is subdivided by means of baffles 30 secured to the shaft 28 into a first chamber 31a facing towards the air nozzle 26 and a second chamber 31b facing away from the air nozzle 26. The chamber 3 1a is connected to a suction blower (not shown).

The connection, in the example illustrated here, is provided by forming the shaft 28 as a hollow shaft and by providing radial bores 28a in the wall of the shaft connecting the interior of the hollow shaft 28 with the first chamber 31a. The supply line 32 to the air nozzle 26 is connected to the exhaust pipe of the suction blower which is connected to the hollow shaft 28 through a control valve. In the illustrated example the control valve consists of a simple control clappet 33 which is provided with an air slot 34. This form of the clappet 33 with the air slot 34 serves to obtain a heating of the carrier material of the sealing tape. If an operation without such heating of the carrier material is desired, a clappet 33 without an air slot is used.

Figure 1A shows a plan view of a folding box blank cut 52. In this the open flap edges are shown in dashed lines and the flap folding edges are shown in dash-dot lines.

The edge to which the factory seal is to be applied is shown in a solid line and is designated by the reference number 53. The blank cut is inserted into the machine in a horizontal position and in the direction of the arrow, i.e. in a position normal to the plane of the drawing.

A light barrier 54 acting on two path length counters is provided in the path of the advancing box blank cut 52. A first one of these path length counters (not shown in Figure 1) acts on the tape advance drive 22a, 22b (see Figure 1) in the sense of starting the tape advance movement, and the other path length counter acts on the tape drive 22a, 22b in the sense of terminating the tape advance movement, by which the tape is drawn off the supply roll 20, and also initiates the cutting off of a tape length by actuating the knife 55 (see Figure 2). In the embodiment illustrated in the drawings, the cutting knife 55 is actuated through an eccentric cam disk 57 which is rotated by a drive and acts on a spring loaded swivel arm respectively a swivel plate 56.

Figure 2 shows a partial view of the activating device of Figure 1 with the cutting device 23 and part of the path length counter assembly.

The path length counters comprise a light source/light receiver arrangement with a continuously revolving toothed disk 60 between said source and receiver, and also two series connected, presettable electronic pulse counters, which are known as such (not illustrated in the drawing). The input of each pulse counter is coupled to the light receiver 59, and the two pulse counters are mutually coupled and coupled to the light barrier 54 in the advance path of the box blank cut (see Figure 1) in such a manner, that the counting in the first pulse counter is started in response to a blocking of the light barrier 54 by a blank cut moving into its light beam, and the counting in the second pulse counter is started when the preset pulse count of the first pulse counter is reached.

In each drive for the tape advance means 22a, 22b (see Figure 1) and for the cutting knife 55 one solenoid actuated combined coupling/brake assembly 61 respectively 62 is provided. A revolving disk 65 with a single slit 63 and cooperating with a light barrier transmitter 64, e.g. comprising a light source and a light receiver, is attached on the drive shaft of the cutting knife 55.

When a pulse is generated by the slit 63 on the disk 65 passing through the light barrier transmitter 64 the cutting knife 55 is stopped by means of the solenoid brake 62.

The device illustrated in the Figures 1 to 3 operates as follows: In preparation of applying the factory seal to folding box blank cuts of a batch with uniform size the flap length A (see Figure 1A) is preset on the adjustment control 66 of the control panel 67 (see Figure 3). This setting of the control corresponds to an analog circumferential length on the toothed disk 60 and also to an analog pulse count at the first pulse counter. similarly, the length B of the factory seal (see Figure 1A) is set on the control 69. This setting corresponds to an analog circumferential distance on the toothed disk 60 as well as to an analog pulse count at the second pulse counter.

During the operation of the device the main drive operates continuously and correspondingly the drives for the advance move ment of the folding box blank cut or roller conveyor 24 and for the toothed disk 60 run continuously, since they are rigidly coupled to the main drive. The rigid coupling between the main drive and the drive for the roller conveyor 24 on one hand and the drive for the toothed disk 60 on the other hand is one of the basic requirements for the exact cutting off of tape lengths and for the accurate disposition of the tape edge on the blank cut, even for highest production rates or throughput rates.

After the box blank cut is moved into the roller conveyor 24, the light barrier 54 is interrupted and by light electrical means and therefore without delay the counting in the first pulse counter is started by the corresponding signal generated in the light barrier. Upon reaching the pulse count preset at the control 66 and correspondingly to the flap length A, this first pulse counter also without delay operates the solenoid coupling of the tape drive 22a, 22b (see Figure 1) and on the other hand starts the count in the second pulse counter. Consequently, the adhesive tape 21 is drawn off the supply roll 20 with a velocity corresponding to the speed of advance of the blank cut on the roller conveyor 24.After the interruption of the light barrier 54 by the advancing blank cut and after the preset pulse count for the flap length A has been reached on the first path length counter the lifting solenoid 22b is actuated and the counter roller 22a is pressed against the tape advance roller 22 and by this the tape is transported in the direction of the drum 29.

Simultaneously, the air control clappet 33 is moved into its position as shown in the drawing, in which the air path through the nozzle 26 is completely opened. As soon as the tape 21 reaches the drum 29, it is drawn against the drum due to the vacuum existing in the interior of the drum and transmitted through the bores 29a. From this time on the drum 29 takes over the transport of the tape, so that the tape transport device comprising the two rollers 22, 22a may be released by appropriate control of the solenoid 22b. The tape 21 is now passed below the air nozzle 26 by the revolving drum 29 and a jet of hot air is directed against the adhesive layer, which is facing upwards.In this, the adhesive layer of the tape containing an adhesive material which is meltable by heat is activated and simultaneously the side of the tape 21 containing the carrier for the adhesive layer is drawn against the peripheral surface of the drum 29 due to the vacuum in the interior of the drum. A firm surface contact between the carrier layer and the surface of the drum 29 is caused and ensures a good transfer of the heat stored in the material of the drum 29 into the tape 21. The heat contained in the carrier layer of the tape ensures a sufficiently extended activated time after the tape has passed out of the activating zone. After the drum has revolved through such a distance, that the leading edge of the tape reaches the second chamber 31b of the drum 29, the tape lifts off the drum 29 due to the now lacking vacuum and is passed out and downwards through a deflecting plate.

After a length of revolution of the drum determined by the length of the factory seal the required length of the tape has moved past the cutting device and the cutting device 23 is now actuated by the second path length counter through the solenoid coupling 62. The leading edge of the tape contained on the supply roll 20 is now disposed in the plane of the cutting knife 55 until the next advance cycle of the rollers 22, 22a, while the cut off tape length is passed through the activation zone.

In this, the movement of the leading edge of the tape 21 by means of the transport device 22 and the drum 29 on one hand, and the advance movement of the folding box blank cut 52 on the roller conveyor 24 on the other hand are adapted by means of synchronization of the drives for both devices and by means of suitable dimensions of the drum 29, so that the leading edge of the factory seal region on the box blank cut 52 and the leading edge of the cut tape length 21 move towards each other.

By means of the light barrier 54 in the conveyor path of the box blank cut 52 and of the control of the two path length counters and the drawing off of the tape 21 from the supply roll 20 by this light barrier, an exact meeting of the leading edge of the cut tape length and the beginning of the region for application of the factory seal 53 on the box blank cut 52 is achieved. In this the flap length A is taken into consideration by introducing a corresponding time delay of travel shift by the first path length counter and its associated pulse counter for the flap length, where this delay or travel shift is relative to the passage of the front edges of the box blank cut 52 past the light barrier 54. This results in an exact meeting of the leading edge of the cut tape length and the beginning of the factory seal 53 on the box blank cut 52, even for high production rates.

The exact length of the cut tape 21 and therefore of the finished applied factory seal is achieved as follows: after the second pulse counter reaches the pulse count preset on the control 69 (see Figure 3), a control signal is supplied to the solenoid brake 61 and the solenoid coupling is disengaged at the same time, the solenoid coupling 62 for the drive of the cutting knife 55 is actuated and both pulse counters are reset to zero. The solenoid brake 61 also operates without a delay and this results in an instantaneous stopping of the removal of tape from the supply roll 20. Thus, the use of solenoid actuated combined coupling/ brake assemblies which operate without delay is desired for ensuring the high accuracy required, even with continuous cycling and in view of the high production rate.

The cutting of the tape lengths for the factory seal from the continuous tape 21 drawn off the supply roll 20 is carried out by actuating the knife arm 56 by means of the excenter 57. In accordance with the high production rates and the corresponding high speed with which tape 21 is drawn off the supply roll 20 the excenter drive is also rotated at high speed. The switching disk 65 revolves together with the excenter 57 and upon passage of the slit 63 through the light beam of the light barrier 64 the solenoid coupling 62 is automatically disengaged and the solenoid actuated brake is energized.In this manner a lagging movement of the excenter 57 is prevented and thus it is ensured that the excenter only carries out a revolution which is sufficient for the cutting action and that the cutting device remains in its disengaged condition and does not inhibit the advance movement of the next succeeding tape length.

The tape length 21, which has been accurately cut in this manner and has been activated and has been placed accurately on the beginning of the region for the factory seal 53, is then pressed onto the factory seal region on the box blank cut 52 by means of suitable pressure rollers (not shown).

As can be seen from the above description of the embodiments in connection with the drawings, the device according to the invention provides a butt-jointed tape sealing of the factory seal on box blanks, especially such blanks consisting of plastic coated cardboard, and ensures a proper sealing with a high quality of the seal and a high accuracy of the contact position between tape and box blank, wherein the high production rates which are possible with the use of an adhesive layer with heat activation can be safely achieved. Thus production rates of 120 to 160 meter/minute or more are achieved, which are much higher than has heretofore been possible It should be understood, of course, that the foregoing disclosure describes only preferred embodiments of the invention and that it is intended to cover all changes and modifications of these examples of the invention which fall within the scope of the

Claims (9)

appended claims. WHAT WE CLAIM IS:

1. A device for manufacturing a buttjointed tape seal on flat objects such as packages, blank cuts, or webs or sheets of paper, cardboard, plastics material, wood and plastics coated cardboard materials, by means of adhesive tape, substantially comprising a supply roll for the adhesive tape, a cutting device for cutting off tape lengths needed for the tape sealing, as well as a transporting device for conveying the tape to an activating means provided with a heater for heating the adhesive layer of the tape length, means for advancing the objects along a travel path, wherein a light barrier is disposed in the path of the advancing object, said light barrier acting on two counters, a first one of said counters being operatively coupled with a drive for drawing off tape from said supply roll to start the advance movement of the tape, and the second one of said counters is operatively coupled with the tape advance drive for termination of the tape advance movement and also is operatively coupled with said tape cutting device for starting the tape cutting action.

2. A device as claimed in claim 1, wherein each said counter comprises a light source/light receiver assembly with a continuously revolving toothed disk rigidly coupled with the transporting device for the object to be taped and disposed between said light source and said light receiver, as well as two series connected presettable pulse counters, both having their input coupled to said light receiver and being electrically coupled with each other and with said light barrier for starting the count in the first pulse counter in response to an interruption of said light barrier by the object to be taped, and for starting the counting in the second pulse counter upon reaching the preset pulse count in said first pulse counter.

3. A device as claimed in claim 1 or 2, wherein the drive for the tape advance device and for the cutting knife are each connected to a solenoid actuated combined coupling/brake assembly.

4. A device as claimed in any preceding claim wherein a disk provided with a single slit and cooperating with a light barrier transmitter is attached to the drive shaft for said cutting knife and a solenoid brake for said cutting knife is provided and coupled to receive actuating pulses generated by said light barrier transmitter.

5. A device as claimed in any preceding claim wherein the activating means comprises an air nozzle with a heater cartridge provided in its interior, and a drum with a perforated periphery revolving on a shaft and disposed in the range of the jet from said air nozzle, the interior of said drum being subdivided in a first chamber facing towards said air nozzle and a second chamber facing away from said air nozzle, where said first chamber facing towards the air nozzle is connected to a suction blower and furthermore a control valve is provided in the air nozzle, said valve being disposed and adapted for opening the air path through the air nozzle during the working period and closing said air path during the idle period of the operation cycle.

6. A device as claimed in claim 5, wherein said drum shaft is formed as a hollow shaft and is provided with radial bores directed towards said first chamber in said drum which is facing towards said air nozzle.

7. A device as claimed in claim 5 or 6, wherein the control valve actuated by the system is connected to the exhaust line of said suction blower, which is connected to said drum respectively to said hollow shaft.

8. A device as claimed in claim 5, 6 or 7, wherein said control clappet is provided with an air passage slot.

9. A device for manufacturing a buttjointed tape seal on an object by means of an adhesive tape, substantially as hereinbefore described with reference to and as illustrated in the accompanying drawings.