STRAPPING MACHINE FOR STRAPPING AN ARTICLE WITH A WELDABLE PLASTIC STRAP

Abstract

 A strapping machine for strapping an article, such as a stack of products or a packaging carton, with a weldable plastic strap comprises
- a machine framework (1),
- a machine table (2) for accommodating the article (3) during the strapping operation,
- a feed device (4) for transporting the article (3) onto the machine table (2) in a conveying direction (F),
- a strapping device (UE), which is assigned to the machine table (2) and is intended for strapping the article (3) with the plastic strap (9), and
- a removal device (20) for transporting the strapped article (9) away from the machine table (2) in the conveying direction (F),
wherein an ejecting device (12), which is arranged in the region of the machine table (2) and is intended for ejecting an article (3) directly from the strapping device (UE) in a direction transverse to the conveying direction (F), is provided.

Description

[0001] The invention relates to a strapping machine for strapping an article, such as a stack of products or a packaging carton, with a weldable plastic strap, having the features specified in the preamble of patent claim 1.

[0002] Said features represent basic components of a strapping machine and contain a machine framework, a machine table for accommodating the article during the strapping operation, a feed device for transporting the article onto the machine table in a conveying direction, a strapping device, which is assigned to the machine table and is intended for strapping the article with the plastic strap, and also a removal device for transporting the strapped article away from the machine table in the conveying direction.

[0003] The problem on which the invention is based resides in it being necessary, in a packaging line in which one station is formed by a strapping machine, for defective articles, for example a stack of products comprising too few products or unsatisfactory products or else a damaged packaging carton, having to be taken out of the handling process. In the case of conventional strapping machines, it is not possible, in the standard configuration, for an article which has been marked or identified as being defective to be ejected laterally. Defective packages are ejected via a separate machine component, for example by an ejector which is adjacent to the strapping machine and with the aid of which a defective package is ejected from the handling process in a direction transverse to the conveying direction.

[0004] This additional machine component disadvantageously means that a packaging line which involves a strapping machine requires a greater set-up surface area and overall installation length.

[0005] Proceeding from this point, the invention is based on the object of improving a strapping machine such that an operation of ejecting an article which has been identified as being defective is achieved without any additional set-up surface area and, in particular, overall installation length of the machine.

[0006] This object is achieved in the characterizing part of claim 1, according to which an ejecting device, which is arranged in the region of the machine table and is intended for ejecting an article directly from the strapping device in a direction transverse to the conveying direction, is provided.

[0007] On account of the ejecting device being arranged according to the invention in the region of the machine table, for example in the form of a pusher, which acts on a defective package from the side and ejects the package from the machine table to the side in a direction transverse to the conveying direction, there is no need for any additional set-up surface area and overall installation length for the ejecting device.

[0008] A particularly advantageous embodiment is one in which the ejecting device is integrated in the machine table. This can be realized, for example, by transverse and longitudinal conveyor belts installed in the machine table. This means that there is no need to have any additional structures above the machine table for the integrated ejecting device.

[0009] A preferred embodiment of an integrated ejecting device is provided by a ball-grid conveyor belt, which is known in the field of handling technology, which forms the surface of the machine table and by means of which it is possible to generate two horizontal movement components of the article in and transverse to the conveying direction independently of one another.

[0010] The German expression "Kugelraster-Förderband" (ball-grid conveyor belt) has been coined by the author of this application and relates to a conveyor-belt solution known as "uni QNB ball belt" from Ammeraal Beltech Holding B.V., 1700AA Heerhugowaard, Netherlands, which sells a modular plastic conveyor belt which has separately drivable balls, arranged in grid form in the belt, and goes by the name given above. With the aid of this so-called "ball-grid conveyor belt", an article arranged thereon can be maneuvered in practice in any desired manner in an x-y plane, as can be seen in the YouTube video clip

https://www.youtube.com/watch?v=L BoHoq Tco.

[0011] This allows optimal realization of the ejecting device according to the invention in the machine table of the strapping machine.

[0012] The ejecting device provided according to the invention can be implemented particularly straightforwardly in a longitudinal strapping device.

[0013] In order to vary the further handling of an ejected, defective article, it is possible, in a preferred development, to provide a transverse conveying device alongside the machine table for the purpose of transporting the ejected article onward. Said transverse conveying device can be formed in particular, in turn, by a ball-grid conveyor belt, as explained above, and/or a conventional roller conveyor and/or a corresponding conveyor-belt arrangement. In particular if use is made of a ball-grid conveyor belt, it is possible, once the article has been ejected, for said article to be transported away again in two different directions by said transverse conveying device. A defective article can therefore be fed very straightforwardly selectively to a repair station or to disposal means by virtue of being transported away in different directions.

[0014] Further features, details and advantages of the invention can be gathered from the following description of an exemplary embodiment with reference to the accompanying drawings, in which:

figure 1

shows a perspective illustration of a strapping machine, and

figure 2

shows a plan view of the strapping machine according to figure 1.

[0015] As can be seen from the drawings, the strapping machine has a machine framework 1, on which a machine table 2 serves to accommodate the article 3, which is illustrated in this case by way of example in the form of a packaging carton, during the strapping operation. The strapping machine shown here is a longitudinal strapping machine of fully conventional design, as far as the handling of the strap around the article 3 and also the formation of a welded loop are concerned. Therefore, a feed device 4, which is located upstream of the machine table 2, as seen in the conveying direction F, and is in the form of a corresponding conveyor belt, is used to convey the article 3 onto the machine table 2 in the conveying direction F. The machine table comprises the conventional components of a strapping device UE, such as the lateral guide jaws 5 and the pressing bars 6, which in the case shown are provided for two longitudinal strapping means, are arranged horizontally and in the conveying direction F and can be lowered onto the article 3 from above, under pressure, via corresponding vertical drives 7 on lateral retaining frames 8. The strap 9 itself is stored on supply rolls 10, 11 and, when the article 3 is moved onto the machine table 2 by the feed device 4, is positioned around the article 3, then guided downwards beneath the plane of the machine table 2 on the rear side of the article 3 with the aid of the manipulators, the so-called "needles" 21, arranged at the end of the pressing bars 6, and then drawn around the packaging carton to form a tensioned loop. The strap is then welded beneath the plane of the machine table 2, at an overlap location, with the aid of the welding head (not visible in the figures). This is all well-known prior art and conventional as far as longitudinal strapping machines are concerned, and there is therefore no need for any more specific explanation with reference to drawings.

[0016] Following this strapping operation, a satisfactory article 3 is transported away from the machine table 2 in the conveying direction F with the aid of a removal device 20, which is illustrated in this case in the form of a roller conveyor, for further handling.

[0017] In order for an article 3 which has been identified as being defective at any point in the handling process for the article to be ejected out of the process, the strapping machine according to figures 1 and 2 provides an ejecting device 12, which is integrated in the machine table 2 and is a ball-grid conveyor belt 13. The latter comprises an endless conveyor belt which is made up of links and has balls 15, each projecting beyond the surface of the belt, arranged in a grid-like manner in the links. These balls can be driven in any desired directions, in particular in the x direction and y direction of the plane of the machine table 2, by separate, additional drive belts, which are arranged beneath the conveyor belt 14, and therefore, with the conveyor belt 14 at a standstill in the conveying direction F, the article 3 located thereon can be transported away in the direction transverse to the conveying direction F, that is to say can be transported away to the side in the y direction, by virtue of the balls 15 rotating about an axis of rotation located parallel to the conveying direction F. This means that a defective article 3 can be ejected laterally directly from the machine in the region of the machine table 2, and onto the adjacent ball-grid conveyor belt 16, from where it can be transported onwards, in a direction transverse to the conveying direction F, onto a roller conveyor 17.

[0018] As is not illustrated specifically in the drawings, it is possible for a defective article 3, following the lateral ejecting operation, to be transported away with the aid of the ball-grid conveyor belt 16 not onto the roller conveyor 17, but elsewhere, parallel to the conveying direction F again.

[0019] For a description of the ball-grid conveyor belts 13, 16, reference is also made to the following websites:

https://www.youtube.com/watch?v=b95LXhBzRT4

http://www.unichains.com/en-US/Products/uni-ONB-Ball.aspx?PID

[0020] As can be seen, in particular, from the plan view according to figure 2, an ejecting device 12 integrated in the machine table 2 makes it possible for the overall length L of a strapping machine with an ejecting means to be reduced to the normal dimensions of a strapping machine without such an ejecting means.

Claims

1. A strapping machine for strapping an article, such as a stack of products or a packaging carton, with a weldable plastic strap, comprising

- a machine framework (1),

- a machine table (2) for accommodating the article (3) during the strapping operation,

- a feed device (4) for transporting the article (3) onto the machine table (2) in a conveying direction (F),

- a strapping device (UE), which is assigned to the machine table (2) and is intended for strapping the article (3) with the plastic strap (9), and

- a removal device (20) for transporting the strapped article (9) away from the machine table (2) in the conveying direction (F),

which comprises

- an ejecting device (12), which is arranged in the region of the machine table (2) and is intended for ejecting an article (3) directly from the strapping device (UE) in a direction transverse to the conveying direction (F).

2. The strapping machine as claimed in claim 1, wherein the ejecting device (12) is integrated in the machine table (2).

3. The strapping machine as claimed in claim 2, wherein the ejecting device (12) is realized by a ball-grid conveyor belt (13), which forms the surface of the machine table (2) and by means of which it is possible to generate two horizontal movement components of the article (3) in and transverse to the conveying direction (F) independently of one another.

4. The strapping machine as claimed in one of the preceding claims, wherein the strapping device (UE) is a longitudinal strapping device.

5. The strapping machine as claimed in one of the preceding claims, wherein a transverse conveying device is arranged alongside the machine table (2), as seen in the conveying direction (F), for the purpose of conveying the ejected article (3) onward.

6. The strapping machine as claimed in claim 5, wherein the transverse conveying device is formed by a roller conveyor (17) and/or a ball-grid conveyor belt (16).

Drawing