EP2485946B1 - Strapping machine for tying of packages - Google Patents

Description

The invention relates to a strapping machine for setting packages, in particular wound into coils metal bands, with at least one strapping around a package strapping, wherein a binding head against the package can be adjusted, comprising a tensioning device and for connecting the ends of the stretched under tension strapping a welding device with at least one arranged in an electrode chamber upper, deliverable welding electrode and a temporarily cooperating with this counter electrode, the welding device is associated with the package towards a slide plate.

The basic principle of such various prior art strapping machines is to position a strapping head on a package to be strapped, guide a strapping band around the package, tension the strapping band, and place its ends one behind the other inside the binding head connect to. The overlapping ends of the prestressed strapping band are materially or positively connected to each other. The removed from a supply roll strapping is separated and the binding head lifted from the package, with all operations are automated.

A strapping machine with tensioning and closing device of the type mentioned is by the EP-B1 0 194 627 known. The slidably with the counter electrode in the plane of the overlap area below the Welding electrodes movable slide plate consists of an upper and a lower plate, which slide on each other or on top of each other. The upper plate is guided on the lower slide plate, in which the counter electrode is embedded. When pressed electrodes and superimposed band ends a welding process enabling circuit is closed. This is when the upper plate has been moved so far that it releases the embedded in the lower plate counter electrode, wherein the strap is just above the counter electrode and below the deliverable welding electrode. After the welding process, the upper plate, which then entrains the lower plate, is moved so far that the welded band loop is released or exposed.

The strapping are subject during transport of the packages, z. As bundled rod or tube-like metal products or coils wound to metal bands, very strong, possibly dynamic loads that must be absorbed by the strapping. Depending on the material quality and properties of the packages, one to three strapping around the circumference of the packages are created to protect against cracking and / or to prevent displacement. In any case, the strapping must be strongly biased, which goes to the limits of tensile and tear strength of the material of the strapping and can also lead to banding on the package.

This problem is compounded by the prior art embedded in the steel slide counter electrode. Because the slide plate, which is also guided in a groove of a support plate, must be large in size, especially in thickness to accommodate the welding forces caused by the pressed-on welding electrodes high forces can. Since the welded strap after separating and pulling the steel slide plate with the embedded counter electrode in the closing or overlapping area according to the thickness of the slide plate, including the groove through the additional height to the periphery of the package springs back, wherein the strapping circumferentially closed applies to the surface of the package, an additional bias is required for this.

The invention is therefore an object of the invention to provide an automated strapping machine that allows a safer, the high loads steady mounting the strapping in a structurally simpler way.

This object is achieved in that the slide plate is formed simultaneously as a counter electrode and in the region of the overlapping ends of the strapping on the underside with support directly on the package is used. By virtue of the fact that the electrode chamber in which the resistance electrodes for welding or tungsten electrodes for protective gas applications are located, depending on the welding process, is provided according to the invention directly between the package and the strapping band during the welding operation, so that no current can flow through the package, and is formed immediately as a counter electrode, which advantageously allows a support directly on the package at the forces occurring, can be achieved after pulling or removing the plate from the welding area to secure the package at a constant clamping force a much higher belt tension of the strapping. Because the way that the welded strapping tape has to cover when putting it on the package is determined only by the small thickness of the slide plate. While the strapping back in the known slide plates with embedded counter electrode and additional guide upon application to the periphery of the package about 10 mm, this path is only about 2 mm with the slide plate according to the invention.

The invention provides that the slide plate has a feed tongue opposite the welding electrode and a plate end part connected to a setting means. There is thus a system separation, which on the one hand the unhindered positioning of the Vorkragzunge to the welding electrode or the welding electrodes and on the other hand, the movement of the Anstellmittel, advantageous as for the delivery or the pressing of the welding electrodes a pneumatic cylinder unit, away from the scene of the welding , namely the rear end of the slide plate allows.

The system separation also opens up the possibility that at least the supply tongue of the slide plate made of copper can be elastically formed to conform to the surface of the package. Namely, the feed tongue or the slide plate may be of small thickness, about 6 mm, because it does not have to absorb any forces due to the direct support on the package, which are rather introduced and collected in the binding head housing and / or the housing-like electrode chamber.

The elastic nestling can be further favored by the fact that preferably in the circumferential direction of the package outer edges of the slide plate are provided with a rounding or an outer radius.

An advantageous embodiment of the invention is that the plate end part carries a formed with a coolant circuit, connectable to a coolant supply cooling block. The coolant circuit can be easily manufactured by drilling channels which can be closed by blind plugs at the openings not required for a coolant supply. The cooling block, which can be fastened on the side facing the package countersunk heads screws on the Plattenendteil, ensures a largely constant during the welding process Temperature level, which reduces the electrode wear or erosion and prevents unnecessary heat transfer into the package.

Another advantageous embodiment of the invention provides for a supporting frame receiving the plate end part, which is formed with a vertically extending, integrally formed a compression spring means having vertical guide, wherein the adjusting means engages the vertical guide. The adjusting means thus acts indirectly on the slide plate, which can be adjusted above the package on the support frame in the binding head housing. The integrated compression spring means serves to secure the end position, d. H. after lifting the welding electrode or the welding electrodes, it brings the slide plate back to its original position.

According to one proposal of the invention is on the housing of the binding head downwardly projecting, auflegender on the surface of the package, provided by the Vorkragzunge in Anstellrichtung end stop provided. This limits the maximum Anstellbewegung the slide plate and also absorbs forces or introduces them into the binding head housing, which can be made as a stable welded construction or cast.

If it is preferable to provide a setting cylinder which acts horizontally on the electrode chamber, staggered spot welds can be achieved with a variable point geometry. In this case, for example, four, five or six welding points can be provided which, with a preferred spot or electrode diameter of 6 to 9 mm, should be approximately 18 to 30 mm apart in order to avoid current or voltage gaps between the individual spot welds.

It is inventively provided that at least two binding head units with each associated slide plates individually for themselves next to each other are arranged. This is to be provided in particular if the strapping band required for the product requires a dimension exceeding a maximum width, commercially available 32 mm.

Further details and features of the invention will become apparent from the claims and the following description of illustrated in the drawings embodiments of the invention.

Figur 1

ein Umreifungsautomat als Prinzipskizze;

Figur 2

als Einzelheit eines Umreifungsautomaten eine aus zwei nebeneinander angeordneten Bindekopfeinheiten bestehende Abbindeeinheit, in der Vorderansicht dargestellt;

Figur 3

den Gegenstand der Figur 2 in einer Seitenansicht;

Figur 4

in vereinfachter Darstellung einen Schnitt entlang der Linie IV-IV von Figur 3;

Figur 5

eine teilgeschnittene Schemazeichnung im Schweißbereich von sich überlappenden Enden des Umreifungsbandes mit erfindungsgemäß zwischen dem Umreifungsband und dem Umfang des Packstücks angeordneter Schieberplatte als Gegenelektrode; und

Figur 6

den Schweißbereich wie zuvor, ohne Schweißelektroden gezeigt, nach dem Stand der Technik.

Show it:

FIG. 1

a strapping machine as a schematic diagram;

FIG. 2

as a detail of a strapping a two adjacent juxtaposed binding head units existing setting unit, shown in front view;

FIG. 3

the object of FIG. 2 in a side view;

FIG. 4

in a simplified representation of a section along the line IV-IV of FIG. 3 ;

FIG. 5

a partially sectioned schematic drawing in the welding area of overlapping ends of the strap with inventively arranged between the strap and the circumference of the package slide plate as a counter electrode; and

FIG. 6

the welding area as before, shown without welding electrodes, according to the prior art.

The FIG. 1 shows very schematically a strapping machine 1 for setting packages 2, here in the form of a metal band. From a direct reel 3, with continuous control and brake, a strapping 4 is unwound and conveyed by a tape guide system 5 to the package 2. One of the direct reel downstream pulley 6 directs the strap 4 initially in a roller straightening 7, which ensures that on the one hand the beginning of the belt is conveyed straight and without kinks through the tape guide system 5 into a binding head 8 and on the other hand, the strapping 4 with decreasing Abwickelradius always straight into the tape guide system 5 passes. In the binding head 8, the beginning of the tape is clamped and the excess strapping tape is reversed until the strapping loop rests against the circumference of the package 2. The excess strapping is rewound via a reverse control of the direct reel 3.

The binding head 8 shown in the embodiment consists of two juxtaposed binding head units 8a, 8b, which are equipped to connect the overlap ends 4a, 4b of the strapped strap 4 with welding devices 9a, 9b, which receive welding electrodes 12 arranged in an electrode chamber 10 in an electrode holder 11. Both the binding head 8 and the binding head units 8a, 8b and the welding electrodes 12 can be adjusted against the circumference of the package 2. For this purpose, the electrode holders 11 are acted on by cylinders 13 bolted to the electrode chambers 10, designed as pneumatic cylinders (compare FIGS Figures 2 and 3 ).

For welding, the welding electrodes 12 are temporarily associated with slide plates 14, which are made of thin copper and are formed with support or system directly on the surface of the package 2 at the same time as a counter electrode. Like that Figures 3 and 4 can be seen, each slide plate 14 has a Vorkragzunge 14a and a Plattenendteil 14b, wherein the slide plates 14 so used for welding or adjusted be that the Vorkragzungen 14 a in the weld region of the tensioned, overlapping ends 4 a, 4 b of the strapping 4 opposite the welding electrodes 12.

Like from the Figures 3 and 4 can be removed, on the plate end portion 14b by means of countersunk screws 15, a cooling block 16 is attached. This is provided with a coolant circuit 17 produced by channel bores, which has connections 18 for the inlet and outlet of a coolant (water). The unneeded outlet openings of the channel bores of the coolant circuit 17 are closed by blind plugs 19. The plate end portion 14b of the slide plate 14 including the cooling block 16 is received by a support frame 20, the linear adjustable in the binding head housing 21 (see FIG. 3 ) is arranged.

For adjustment of the support frame 20 and thus positioning of the slide plate 14 is provided as adjusting means 22, a pneumatic cylinder unit which engages with a piston rod 23 to a orthogonal to the support frame 20 extending, columnar vertical guide 24.

The FIG. 3 shows that the binding head housing 21 is formed with a downwardly projecting, the Vorkragzunge 14a of the slide plate 14 at a distance opposite end stop 25 and also a horizontally acting on the electrode chamber 10 Anstellzylinder 26. The adjusting cylinder 26 allows variable, in particular offset welding points.

How out FIG. 5 can be seen, the outer edges of the slide plate 14 in the circumferential direction 27 or in juxtaposition of two slide plates, the respective outer edges of the Vorkragzungen 14a (see FIG. 4 ), which further favors the adaptation or nestling of the anyway because of their small thickness elastic slide plate 14 and 14 a, 14 b on the outer circumference of the package 2.

The FIG. 5 makes comparisons with the in FIG. 6 shown known Schieberplattenausführung in which the dashed line counter electrode 114a is embedded in the lower steel slide 114, wherein the steel slide 114 is also guided in grooves of side walls, the great advantage of the achieved gain in clamping force clearly. Because after FIG. 6 For example, a high amount of stretch of the strapping band is required because a great distance has to be overcome by the steel slider and its side wall guides, which then results in the loss of clamping force when the closed loop springs back against the circumference of the package 2. The extra stretch there can therefore be reduced FIG. 5 largely completely use as clamping force.

LIST OF REFERENCE NUMBERS

1

strapping machine

2

Package / metal band

3

direct reel

4

strapping

4a, 4b

Overlapping ends of the strapping band

5

Tape guide system

6

idler pulley

7

Roll straightener

8th

binding head

8a, 8b

Binding head unit

9a, 9b

welder

10

electrode chamber

11

electrode holder

12

welding electrode

13

Cylinder / pneumatic cylinder for welding electrode delivery

14

slide plate

14a

Vorkragzunge

14b

Plattenendteil

15

countersunk

16

cooling block

17

Coolant circuit

18

Connection / coolant inlet or outlet

19

blind plug

20

supporting frame

21

Binding head housing

22

clamping means

23

piston rod

24

vertical guide

25

end stop

26

Adjusting cylinder

27

circumferentially

28

curve

114

Metal seal

114a

counter electrode

Claims (9)

1. An automatic strapping machine (1) for tying off packages (2), particularly metal strips wound into coils, by means of at least one strapping band (4; 4a, 4b) placed around the package (2), wherein a tying head (8, 8a, 8b) can be placed against the package, wherein said strapping machine comprises a tensioning device, as well as a welding device (9a, 9b) with at least one upper, adjustable welding electrode (12) in an electrode chamber (10) and a counter electrode temporarily interacting with the welding electrode in order to connect the ends (4a, 4b) of the tensioned strapping band (4), and wherein a sliding plate (14) is associated with the welding device (9a, 9b) toward the package (2),
   characterized in
   that the sliding plate (14) is simultaneously realized as counter electrode and used on the underside of the strapping band (4) in the region of its overlapping ends (4a, 4b) while being directly supported on the package (2), wherein the sliding plate (14) features a projecting tab (14a) that lies opposite of the welding electrode (12) and a plate end part (14b) that is connected to an adjusting means (22).
2. The automatic strapping machine according to Claim 1,
   characterized in
   that the plate end part (14b) carries a cooling block (16) that is realized with a coolant circuit (17) and can be connected to a coolant supply.
3. The automatic strapping machine according to Claim 1 or 2,
   characterized
   by a supporting frame (20) that receives the plate end part (14b) and is realized with a vertical guide (24) that extends orthogonal to the supporting frame and features an integrated pressure spring means, wherein the adjusting means (22) engages on the vertical guide (24).
4. The automatic strapping machine according to Claim 3,
   characterized
   by an adjusting means (22) in the form of a pneumatic cylinder unit.
5. The automatic strapping machine according to one of Claims 1 to 4,
   characterized in
   that the sliding plate (14) consists of copper and at least the projecting tab (14a) is realized such that it elastically adapts itself to the surface of the package (2).
6. The automatic strapping machine according to Claim 5,
   characterized in
   that the outer edges of the sliding plate (14; 14a) referred to the circumferential direction (27) of the package (2) are provided with a rounding (28).
7. The automatic strapping machine according to one of Claims 1 to 6,
   characterized in
   that a downwardly projecting end stop (25), which places itself onto the surface of the package (2) and is spaced apart from the projecting tab (14a) in the adjusting direction, is provided on a housing (21) of the tying head (8).
8. The automatic strapping machine according to one of Claims 1 to 7,
   characterized
   by an adjusting cylinder (26) that horizontally engages on the electrode chamber (10).
9. The automatic strapping machine according to one of Claims 1 to 8,
   characterized in
   that at least two tying head units (8a, 8b) with respectively associated sliding plates (14; 14a, 14b) are individually arranged adjacent to one another.

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