CA2101511A1

CA2101511A1 - Package strapping machine

Info

Publication number: CA2101511A1
Application number: CA002101511A
Authority: CA
Inventors: Peter Ludtke
Original assignee: Maschinenfabrik Gerd Mosca AG
Current assignee: Maschinenfabrik Gerd Mosca AG
Priority date: 1992-08-01
Filing date: 1993-07-28
Publication date: 1994-02-02
Also published as: DE4225480A1; EP0582161A1

Abstract

ABSTRACT OF THE DISCLOSURE

A machine for strapping packages having a package table possessing a slot in the strapping plane through which a strapping material may pass; a strap wrap-around device possessing a gripper consisting of an upper part and a lower part which in its starting position grips the leading section of the strapping material below the package table, and then rotates around the package in the strapping plane, at the same time withdrawing the strapping material from a roll, and then returns to its starting position; a tensioning device which tensions the loop formed by the strapping material around the package; a sealing device which bonds or welds together overlapping sections of the loop, and which consists of an anvil plate slidingly arranged immediately beneath the package in the overlapping zone of the loop, and of a sealing head which can be moved against the overlapping sections and the anvil plate; a first clamp which holds the leading section of the loop close to the end of the anvil plate facing towards the strapping feed-in point; a second clamp which holds the rear section of the loop close to the end of the anvil plate facing away from the feed-in point of the strapping material; a cutting device, which severs the loop from the strapping material once the gripper has gripped the leading section for the subsequent loop, characterized in that the first clamp is arranged at the same height as the anvil plate and below this clamp and above the gripper in its end and starting position, a pusher is arranged which pushes the leading section of the loop below the underside of the anvil plate after the clamp has closed and the gripper has opened, the said pusher device being retractable to its starting position before the sealing head moves upwards, and further characterized in that the feed-in point of the strapping material is arranged on a level higher than the underside of the upper part of the gripper in its starting position, and after the clamp has closed the lower part of the gripper can be moved out of the strapping plane and, before the sealing head and the movable blade move upwards, the lower part of the gripper can be moved back into the strapping plane to grip the leading edge of the subsequent loop.

Description

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A Package Strapping Machine The invehtion relates to ~ machine consisting of the following components for strapping or banding packages:

- a package table having a slot arranged in the strapping 05 plane through which strapping material can pass;

- a wrap-around device having a gripper comprising an upper and a lower part which, in its starting position below the package table, grips the leading part of the strapping material and then rotates around the package in the strapping plane, at the same time withdrawing strapping material from a roll of same, and then returns to its starting position;

- a tensioning device which tightens the loop formed by the strapping material around the package - a sealing device which bonds or welds together the overlapping sections of the loop and comprises an anvil plate slidinglY arranged immediately below the package in the overlapping range of the loop, as well as a sealing head which can be moved into contact against the overlapping sections and the anvil plate;

- a first clamp which holds the leading section of the loop close to the end of the anvil plate facing towards the feed-in point of the strapping;

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- a second clamp which holds the rear section of the loop close to the end of the anvil plate facing away fro~ the feed-in pOillt of the strapping, and 05 - a cutting device which cuts the loop of strapping material once the gripper has taken hold of the start of the strapping for the next loop.

8trapping machines of this type are known from German Patent ~pplications DE-OS 22 25 297 and DE-OS 22 25 298.

In these prior art machines the first clamP as well as the second clamp operate against the underside of the anvil plate and, once the first clamp is closed and while the overlapping ends of strapping are being welded, the wrap-around device reverses and the gripper is returned to its starting position, where it picks up a new leading section of strapping material to start the next strapping cycle. Because of the relativelY large distances ~' through which the gripper must travel in order to wrap the strapping around the package, the known machines operate relatively slowly~ In addition, both parts of the gripper must be moved out of the strapping plane so that the gripper can be returned from the end position of the strapping cycle to the starting position~ These movements of the sripper also consume a lot of time and require a great deal of control input. In the known strapping machines the strapping material is a relatively :, .. . . . .

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thick plastic strap, the overlapping sections of which are partially melted by means of a heating el0ment before the sealing head presses the overlapping and partiallY melted sections against each other and against the anvil plate, thereby joining 05 the ends of th0 loop.

In other strapping machines, described in German Patent DE-PS 1 297 538 and German Patent ~pplication DE-OS 1 956 425, in which~
the gripping devices encircle the package, the gripper transfers ~- the strapping material, after the latter has been wrapped around the package, to clamps operating in conjunction with the sealing devicei during the sealing and cutting process, one clamp holds the end of the strapping material coming from the roll, and then takes and passes on the new leading end of the strapping to the gripper. This clamp which, in addition to holding the strapping fast, must also perform the function of an intermediate transporting device, requires the provision of relatively complex control mechanisms in the prior art machines~

It is the purpose of the invention to design strapping machines of the kind described at the beginning, and in such a way that their operating speed can be considerably increased while at the same time the control mechanism is simplified~

Thi~ task is solved in the manner according to the invention by arranging the first clamp at the same level as the anvil plate ' below this clamp and above the gripper in its end and starting position is arranged a pusher which, once the clamp has closed and the gripper has opened, pushes the start of the loop below the underside of the anvil plate, after which it returns to its S starting position before the sealing head moves upwards; also the feed-in point of the strapping material is arranged at a higher level than the underside of the upper part of the gripper in its starting positioni and, once the clamp has closed, the lower part of the gripper can be moved out of the straPping plane and then, before the sealing head and the movable blade travel upwards, it can be moved back into the strapping plane to grip the leading section of the next loop.

The strapping machine according to the invention offers the advantage that the starting position of the gripper prior to the start of strapping cycle, and the end position of the gripper at the end of the strapping cycle, are exactlY the same. The wrap-around device can move very rapidly and the starting and end .
positions of this device and of the griPper can be defined by a pivotable stop. By briefly moving the lower part of the griPperout of the strapping plane, the strapping material is positioned in such a way that after moving the lower part of the gripper back into the strapping plane, and by closing the two parts of the device, the start of the next loop in the sequence is engaged in the gripper. The movements of the movable stop, of the clamps, of the pusher for the start of the loop, of the lower part of the , ~ .
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gripper, of the sealing head and of the movable blade, can all be relatively small, and those of the wrap-around device bearing the gripper can be rapid1 so that a high operating speed is attained. `

05 The wrap-around device which moves the gripping element around the package maY be a power-driven ring-shaped element completely encircling the package and the package table 9 or it may be a crank arm whose free end carrying the griPper extends as far as the strapping plane. However, the griPper may also be arranged on o a conveyor chain or belt which encircles the package table and the package in or near the strapping plane. A movable stop is arranged on the frame of the machine in such a way as to engage with a stoP on the wrap-around device to arrest the motion of the latter when the gripper has reached its end/starting position.
When the new strapping cycle commences, the frame-mounted stop is pivoted brieflY out of the path of the stop which is mounted on the wrap-around device.

The sealins head is advantageously an ultrasonic welding head, so that even relativelY thin, untreated plastic foil can be used as the strapping material.

The outlet of an adhesive dispensing system is advantageously arranged below the anvil Plate and in the area above the sealing head. Through this outlet a section of a plastic tape or an adhesive can be inserted, at right angles to the strapping plane, : , ' ' ' , :
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between the overlapping end sections, which are to be joined together, of the looP of strapping material encircling the package. This adhesive dispensing system makes it possible to use as strapping material not only weldable plastic straps but also 05 strapping made of paper, woven strapping, non-woven fibre strapping and similar. The adhesive is activated by means of the ultrasonic sealing head.

Further features of the invention can be taken from the sub-claims.

In the following description, an embodiment of the invention is explained in more detail, making reference to the drawings, which show Fig. 1: ~ diagrammatic view of the package strapping machine according to the invention, showing the essential parts which come into operation during the strapping of a package.

Fig. 2: The essential operational parts after the strap has been placed around the package.

Fig. 3: The parts of the machine after the gripper has opened up.

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Fig. 4: The parts of the machine in operation when the leading section of the loop is guided below the anvil plate.

Fig. 5: The parts of the machine in operation when the loop is 05 closed and when this loop is severed from the rest of the strapping material.

~s can be seen in Fig. 17 the package 1 which is to be strapped is placed on a table 2 which is provide with a gap in the strapping plane through which the strapPing material 4 can be passed. The package table 2 and the package 1 are surrounded by a wrap-around device 8 which, in the embodiment described here, ]5 takes the form of a ring~shaped element driven by a drive belt.
gripper 7 and 7', which is arranged on this wrap-around device 8, takes the leading section of the strapping material 4 around the package 1, at the same time drawing straPPing material from the roll 3. The strapping material 4 is guided from the roll 3 via a tensioning device 5 and a deflector roll 6 and then through a cutting device 16, 17. The frame of the machine possesses a stop 20 which acts in conjunction with a stop 21 on the wrap-around device 8. ~t the start of the strap wrap-around motion the stop 20 is briefly moved out of the path of the stop 21 attached to 2s the ring-shaped wrap-around device 8, so that the ring 8 can be rotated through 360 until its stop 21 again comes into contact 5 ~ ~

with stop 20. This is the position illustrated in Fig~ 2. The tensioning device 5 keeps the strapping material 4 under tension so that the clamps 11 and 12 can hold the loop 4' while it is under tension. The first clamp 11, which secures the leading 05 section of the loop 4' near the end of the anvil plate 10 facing towards the feed-in point 18 of the strapping material, is arranged on the same level as the anvil plate 10 and clamps the strapping material 4 between itself and the edge of the anvil plate 10 facing towards the feed-in point 18 of the strapping 0 material. The second clamp 12 holds the strapping material 4 in the rear section of the loop 4' between itself and the underside of the anvil plate 10, near the edge of the anvil plate 10 facing away from the feed-in point 18 of the strapping material~

To ensure that the leading section of the loop 4' comes to rest between the anvil plate 10 and the rear section 15 of the loop 4', a pusher 13 is provided which pushes the leading section 14 of the strapping under the anvil plate 10, after the gripper 7, 7' has opened and the lower part of the gripper 7' has been retracted from the strapping plane. The pusher 13 for the leading section of the strapping 14 moves substantially parallel to the underside of the anvil plate 10~ This pusher 13 maY be designed in such a way that, rather like a flatiron, it presses the leading section of the strapping 14 against the underside of the anvil plate 10~ Because the feed-in point 18 of the strapping material is arranged at a higher level than the upper part 7 of ... .
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the gripper, the strapping material 4 springs back against the upper part 7 of the gripper, after the lower part 7' has been rel;racted, so that this lower part 7' can then be moved back into the strapping plane (see Fig~ 4) J and the gripper 7, 7~ can be 05 closed again, so that it grips the leading edge of the next loop.

As is shown in Fig. 5, by raising up a sealing head and a movable blade 17, the loop 4' can be severed from the rest of the strapping material 4, and the rear section 15 of the loop 4' is joined with the leading section 14 of the loop 4'. If the strapping material 4 consists of a weldable plastic, then the sealing head 9, which preferably takes the form of an ultrasonic weldins head, can weld together end sections 14 and 15 of the loop 4'. If the strapping material 4 ~oes not consist of a weldable material, but for example of paper or a woven textile fabric, the strapping machine can be provided with an adhesive supply system 19, shown in Fig. 3, which inserts a section of plastic tape or adhesive between the ends 14 and 15 of strapping, at right angles to the strapping plane, before the sealing head 9 presses the end section 15 of the loop 4' against the leading section 14 of the loop 4' and joins the ends 14 and 15 of the strapPing together by means of ultrasound.

supplyins a section of plastic tape and bonding together the ends of a loop of paper or fabric strapping material by means of an ultrasonic generator is particularlY advantageous because it is - ,. .

, 2 ~ ral very easy to supply a section of plastic tape, and when ultrasound is used the heat ~enerated does not exceed the amount needed to melt the plastic.

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List: of reference numbers 1 Package 2 Package table 05 3 Roll of strapping material 4 Strapping material 4~ Loop Tensioning device 6 Deflector roll lo 7 Upper part of gripper 7' Lower part of gripper 8 Strap wrap-around device 9 Sealing head Anvil Plate 11 First clamp 12 Second clamp 13 Pusher for leading section of loop 14 Leading section of loop Rear section of loop 16 Fixed blade 17 Movable blade 18 Strapping feed-in point 19 Adhesive dispenser Stop mounted on machine frame 21 Stop mounted strap wrap-around ring - :. -, ..
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Claims

1. A machine for strapping packages (1) having - a package table (2) possessing a slot in the strapping plane through which a strapping material (4) may pass;

- a strap wrap-around device (8) possessing a gripper consisting of an upper part (7) and a lower part (7') which in its starting position grips the leading section (14) of the strapping material (4) below the package table (2), and then rotates around the package (1) in the strapping plane, at the same time withdrawing the strapping material (4) from a roll (3), and then returns to its starting position:

- a tensioning device (5) which tensions the loop (4') formed by the strapping material (4) around the package (1);

- a sealing device (9, 10) which bonds or welds together overlapping sections (14, 15) of the loop (4'), and which consists of an anvil plate (10) slidingly arranged immediately beneath the package (1) in the overlapping zone (14-15) of the loop (4'), and of a sealing head (9) which can be moved against the overlapping sections (14, 15) and the anvil plate (10);

- a first clamp (11) which holds the leading section of the loop (4') close to the end of the anvil plate (10) facing towards the strapping feed-in point (18);

- a second clamp (12) which holds the rear section of the loop (4') close to the end of the anvil plate (10) facing away from the feed-in point (18) of the strapping material;

- a cutting device (16, 17), which severs the loop (4') from the strapping material (4) once the gripper (7, 7') has gripped the leading section for the subsequent loop, characterized in that the first clamp (11) is arranged at the same height as the anvil plate (10) and below this clamp (11) and above the gripper (7, 7') in its end and starting position, a pusher (13) is arranged which pushes the leading section of the loop (14) below the underside of the anvil Plate (10) after the clamp (11) has closed and the gripper (7, 7') has opened, the said Pusher device being retractable to its starting position before the sealing head (9) moves upwards, and further characterized in that the feed-in point (18) of the strapping material (4) is arranged on a level higher than the underside of the upper part (7) of the gripper in its starting position, and after the clamp (11) has closed the lower part (7') of the gripper can be moved out of the strapping plane and before the sealing head (9) and the movable blade (17) move upwards, the lower part (7') of the gripper can be moved back into the strapping plane to grip the leading edge of the subsequent loop.

2. A machine according to Claim 1, characterized in that the first clamp (11) holds the strapping material (4) at the front end of the loop (4') between itself and the edge of the anvil plate (10) facing the feed-in point of the strapping material.

3. A machine according to Claims 1 or 2, characterized in that the second clamp (12) holds the strapping material (4) at the rear end of the loop (4') between itself and the underside of the anvil plate (10) close to the edge of the anvil plate (10) facing away from the feed-in point (18) of the strapping material.

4. A machine according to one of the Claims 1 to 3, characterized in that the cutting device (16, 17) is arranged in the direction of feed (18) of the strapping material immediately behind the gripper (7, 7') in its starting position, and the upper stationary blade (16) is arranged at approximately the same height as the upper Part of the gripper (7).

5. A machine according to one of the Claims 1 to 4, characterized in that sealing head (9) is an ultrasonic sealing head.

6. A machine according to one of the Claims 1 to 5, characterized in that a device (19) dispensing a meltable plastic or adhesive at right angles to the strapping plane is arranged below the anvil plate (10) and in the area above the sealing head (9), and once the pusher device (13) has returned to its starting position, and prior to the sealing head (9) moving upwards, this device (19) dispenses a section of plastic tape or adhesive between the two overlapping sections (14, 15) of the loop (4').

7. A machine according to one of the Claims 1 to 5, characterized in that the strap wrap-around device (8) possesses a stop (21) which acts in conjunction with a stop (20) arranged on the frame of the machine, and this latter stop can be moved out of the path of the stop (21) on the wrap-around device (8) at the start of the strapping cycle.

8. A machine according to one of the Claims 1 to 7, characterized in that the strap wrap-around device (8) is a ring-shaped element mounted on at least three rollers.