EP3891075B1 - Band guide frame with magnetic closure device - Google Patents

Description

The invention relates to a strapping machine with a strap guide frame with a strap guide channel and a plurality of closing elements distributed over the length of the channel, which can be moved from a position that closes the channel into a position that opens the channel against a restoring force, the closing elements having a closing force that is generated by a magnetic closing device is generated, can be fixed in the position closing the channel, the magnetic closing device comprising two cooperating and magnetically attracting closing parts, one of which is fixed to a closing element and the other of which is fixed to the tape guide frame. The invention also relates to a method for strapping objects with such a strapping machine.

Such a strapping machine is known from the publication EP 1 702 844 B1 and the JP 2000 203514 A . The magnetic closing device reliably and wear-free generates a closing force that keeps the strap guide channel closed. After the strapping has been completed, a retraction drive pulls the strapping back out of the strap guide channel, the strap being pulled against the closing elements and the closing elements opening against the closing force. In the embodiment described here, the closing elements are flap-shaped and pivotably attached to the tape guide frame in such a way that they cover the tape guide channel when the closing parts on the tape guide frame and the closing element abut against one another, the magnetic force of the closing parts fixing the closing element in this closed position. When the closing elements are opened by pulling the strapping out of the strapping channel, a force greater than the magnetic force must act is to open the closing elements. The result of this is that the strapping slips past the edge of the closing element with increased force when it is opened, as a result of which considerable wear occurs, which leads to increased maintenance and repair costs. The pamphlet DE 25 07 717 C3 discloses a strapping machine with a locking device for channel flaps, which are operated via cables. A tensile force is applied to the ropes by a spring, a weight, a pneumatic or hydraulic piston, or electromagnetically.

In addition, the strap shifts due to the undefined opening movement of the flaps. As a result, the strapping cannot be precisely positioned on the product.

Another significant disadvantage is that a minimum distance between the product and the frame must be maintained so that the flaps open reliably. The choice of flap geometry also depends to a large extent on the dynamic processes when opening the flaps by pulling out the tape. The flap geometries cannot be chosen freely with the aim of providing the best possible frame coverage, but must be defined in such a way that the flaps can be opened safely.

The noise generated by the flaps when they are opened when the strap is pulled out is also very high. The effort required to open the flaps, which are subjected to magnetic force, also means that a drive motor with a gear stage is used to generate the necessary retraction force for the strapping band.

The object of the invention is to create a strapping machine in which at least some of the aforementioned disadvantages are eliminated. The aim is to reduce the wear on the closing elements (flaps), to avoid displacement of the strapping when the flaps are opened, to enable the flap geometries to be freely selected, to reduce noise and the required retraction force.

This object is achieved according to the invention by the features of claims 1 and 9, respectively.

The position of part of the magnetic closing device can be changed by the displacement means in such a way that the closing force drops to zero. This is the case, for example, when a magnetic closure part is moved from a position in which it faces and attracts another magnetic closure part so that it faces a non-magnetic material section, e.g. made of plastic, so that a magnetic closure force is no longer generated . The locking parts can then be opened without resistance. If the closing parts are arranged pivotably at the bottom on a horizontally extending section of the tape guide frame, the closing parts can pivot into the open position due to their weight when the closing force is removed. By eliminating the closing force, wear and tear on the closing parts when the strap is opened is largely avoided.

However, the displacement means can also be used to configure the magnetic closing device such that in an open position two magnetic closing parts with opposite polarity face one another, one of which is arranged on the tape guide frame and one on the movable closing element. The two closing parts then repel each other and generate an opening force that pushes the closing element into the open position. In this way, any contact between the strap and the closing part when the strap loop formed in the strap guide channel is pulled together can be avoided.

The closure members may be flap-shaped and pivotally attached to the tape guide frame. In the closed position, they cover the tape guide channel. Flap-shaped closure elements are the most common Embodiments of closing elements. The locking elements can be L-shaped, with their lateral legs being pivotably attached to the tape guide frame and the legs pointing towards the center of the tape guide frame covering the tape guide channel. But there are also other flap-shaped closing elements known, for example from EP 1 702 844 B1 . What is important is that the sections of the closing elements which cover the strap duct can be moved in such a way that the strap duct is released and a strap in the strap duct can be pulled out in order to form a tight-fitting loop around a package. Typically, a plurality of closure elements are distributed along the length of the tape guide frame. Each of the closing elements can form a flap. In the case of L-shaped closure elements, it is also known to use respective pairs of closure elements, each of which covers half of the belt duct. These pairs of flap-shaped closing elements then unfold like wings when the tape guide channel is opened.

In practice, the magnetic locking means may comprise two cooperating locking members, one fixed to a locking member and the other fixed to the tape guide frame. One of the two closing parts should be permanent magnetic in order to generate the closing force when aligned with the second closing part. The other closure part can be either permanent magnetic or ferromagnetic and is magnetically attracted to the first closure part.

As mentioned above, in practice the displacement means can displace one of the cooperating closing parts. For the several closing elements of the tape guide frame, the magnetic closing device can have a displacement means which causes the closing force to be canceled for each closing element, for example by displacement of one of the two interacting closing parts. Thus, by activating the displacement means, for example a displacement, all the closing elements of the sliver guide frame can be opened or at least made powerless at the same time.

In practice, the displacement means can displace the adjustable closure part from a closed position, in which it is close to the fixed closure part, to an open position, in which it is remote from the fixed closure part. Due to the greater distance, no effective magnetic closing force is then generated.

Furthermore, the magnetic closing device may have an opening part which is close to a closing part in the opening position. If the affected closing part and the opening part are both permanent magnets and like poles of the closing part and the opening part face each other, a repelling magnetic force arises between this closing part and the opening part, which pushes the closing element into the open position. In the open position of the closing element, the strap guide channel can be completely open, so that the strapping strap can emerge from the strap guide channel without coming into contact with the closing element.

As mentioned, the magnetic closing device can have a closing part on each closing element and a second closing part which is assigned to this closing part and is fastened to the tape guide frame. These two closure parts magnetically pull the closure element into the closed position.

The displacement means can in practice be attached to the tape guide frame. The displacement means can have an adjustment drive which effects the displacement of the closing parts on the strap guide frame. The adjusting drive can effect a displacement of the adjustable closing part in both directions, ie into the closed position and into the open position. However, the adjusting drive can also only act on one side and generate an opening force with which the adjustable closing part is shifted into the open position. The closing parts that interact with one another can generate an oppositely acting magnetic closing force, with which the adjustable closing part is displaced into the closed position.

In a particular embodiment of the strapping machine, each of the two pivotable closing elements located opposite one another can have a limb projecting towards the middle of the strap guide frame, with two free end faces of these limbs adjoining one another in the position closing the channel and with each of these limbs starting from the respective free end face having a Has a gap and the opposite columns together form the tape guide channel. In other words, the mutually facing short legs of the L-shaped flaps form an integrated strap channel, because they have parallel and aligned gaps starting from their free end faces, each of which forms one half of the strap guide channel. A corner member of the strap guide frame may have similar strap channel halves integrated into the flaps and running along a 90° circular path. These strap channels or sections of the strap channels integrated into the flaps enable the strapping to be guided very precisely with little play.

The invention also relates to a method for strapping objects with a strapping machine which has a strap guide frame with a strap guide channel and a plurality of closing elements arranged distributed over the channel length, which can be moved against a restoring force from a position closing the channel into a position opening the channel, wherein the closing elements can be fixed in the position closing the channel by means of a closing force which is generated by a magnetic closing device. In order to reduce the wear on the closing elements, the closing force is canceled out by adjusting the magnetic closing device or an opening force directed counter to the closing force is generated.

The magnetic locking device may comprise two cooperating locking parts, one of which is fixed to a locking element and the second of which is fixed to the tape guide frame and one of which is permanent magnetic and the other of which is either permanent magnetic or is ferromagnetic, one of the locking parts being displaced to adjust the magnetic locking device.

The adjustable closure member is translatable from a closed position near the fixed closure member to an open position remote from the fixed closure member.

The magnetic closing device may have an opening part which is close to one of the closing parts in the open position, this closing part and the opening part being permanent magnets and like poles of the closing part and the opening part facing each other.

In practice, an adjusting drive can generate an opening force with which the adjustable closure part is displaced into the open position, with the interacting closure parts generating a magnetic closing force with which the adjustable closure part is displaced into the closed position.

Fig. 1

eine schematische Seitenansicht einer Umreifungsmaschine;

Fig. 2

eine isolierte Seitenansicht eines Bandführungsrahmens (Klappenrahmen), der auf der Seite liegend angeordnet ist, so dass der in Fig. 2 untere Schenkel der linke Schenkel in Fig. 1 ist;

Fig. 3

eine Schnittansicht durch den in Fig. 2 linken Schenkel des Bandführungsrahmens aus Fig. 2;

Fig. 4

eine Seitenansicht der Einzelheit IV des Bandführungsrahmens aus Fig. 2 mit geschlossenen Schließelementen, wobei ein Schließelement entfernt ist;

Fig. 5

eine Schnittansicht entlang der Schnittlinie V - V in Fig. 4;

Fig. 6

eine Schnittansicht entlang der Schnittlinie VI - VI in Fig. 4;

Fig. 7

eine Seitenansicht eines Abschnitts des Bandführungsrahmens mit geöffneten Schließelementen, wobei ein Schließelement entfernt ist;

Fig. 8

eine Schnittansicht entlang der Schnittlinie VIII - VIII in Fig. 7;

Fig. 9

eine Schnittansicht entlang der Schnittlinie IX - IX in Fig. 7;

Fig. 10

eine vergrößerte Ansicht der Einzelheit X in Fig. 3, welche eine Ecke des Bandführungsrahmens zeigt;

Fig. 11

eine Entlang der Schnittlinie XI - XI geschnittene Ansicht der Ecke des Bandführungsrahmens aus Fig. 10;

Fig. 12, 13

vergrößerte Ansichten der Schnittdarstellungen der Fig. 5 und 6;

Fig. 14

eine vergrößerte Ansicht einer Schnittdarstellung einer alternativen Ausführungsform des Bandführungsrahmens mit geschlossenen Schließelementen;

Fig. 15

eine Schnittdarstellung des Bandführungsrahmens aus Fig. 14 mit geöffneten Schließelementen.

Further practical embodiments and advantages of the invention are described below in connection with the drawings. Show it:

1

a schematic side view of a strapping machine;

2

an isolated side view of a tape guide frame (flap frame) arranged lying on its side so that the in 2 lower limb the left limb in 1 is;

3

a sectional view through the in 2 left leg of the tape guide frame 2 ;

4

Figure 12 shows a side view of detail IV of the tape guide frame 2 with closure members closed with one closure member removed;

figure 5

a sectional view along line V - V in 4 ;

6

a sectional view along line VI - VI in 4 ;

7

Figure 14 is a side view of a portion of the tape guide frame with latches open, with one latch removed;

8

a sectional view along line VIII - VIII in 7 ;

9

a sectional view along line IX - IX in 7 ;

10

an enlarged view of detail X in 3 12 showing a corner of the tape leader;

11

Figure 12 shows a sectional view of the corner of the tape guide frame along section line XI - XI 10 ;

12, 13

enlarged views of the sectional views of the Figures 5 and 6 ;

14

Figure 12 is an enlarged sectional view of an alternative embodiment of the tape guide frame with the closure members closed;

15

shows a sectional view of the tape guide frame 14 with open closing elements.

The one in the 1 The strapping machine 1 shown is used for strapping objects 7 with a strap 2 which is drawn off from a supply roll 3 by a pull-in device 4 and fed to a tape magazine 5 . From there, the strap 2 is fed by a strap conveyor device 6 through a tensioning device 8 to a strap channel on a strap guide frame 9, so that the strap 2 forms a loop. The strapping band 2 is then pulled back by the drive of the band conveyor device 6 so that the band loop lies snugly against the object 7 . Now the clamping device 8 is activated, so that the strap loop is pulled around the object 7 with a predetermined high clamping force. The belt conveyor device 6 and the tensioning device 8 together form the belt drive. They can also be combined to form a drive device.

The tensioned loop is then cut off from the tape supply. The start of the loop is connected to the end of the loop by means of a closing unit 10 . In practice, the closure unit 10 consists, for example, of a welding device which welds the two ends of the packing tape loop that has been formed to one another. The closure unit 10 welds the film-like plastic material from which the strap is made. The conveyor that transports the item 7 in and out of the strapping zone within the strap guide frame is in 1 not shown.

The 2 shows an isolated representation of the tape guide frame 9, which is designed as a flap frame, in side view. The tape guide frame 9 in 2 is 9 in. from the tape guide frame 1 rotated 90° anti-clockwise so that the interrupted leg, on which the locking unit is arranged, is on the right. The 3 Figure 13 shows a sectional view of the left leg of the tape guide frame 2 . In 2 it can be seen that along the straight sections of the tape guide frame 9 several successive flaps 11 are arranged, which closing elements for the tape guide channel 24 (see 12 ) form. Only some of the flaps 11 of each of the three continuous legs of the tape guide frame 9 are in 2 provided with reference numbers.

4 shows an enlarged side view of detail IV in 2 , which covers a section of the in 2 underlying leg of the tape guide frame 9 represents. Here is a flap 11 shown in full and two flaps 11 partially. A flap has been removed in the middle to better explain the function.

The figure 5 shows a representation of the cut along the section line VV 4 . The section line VV runs through a bearing pin 13, which in particular figure 5 can be seen and which pivotally supports the flap 11 and connects it to the tape guide frame 9 . It can be seen that the flap 11 has approximately the cross section of an L rotated by 180°, the short leg of which projects towards the center of the tape guide frame 9 into the Figures 5, 6 , 8, 9 , 12:13 runs horizontally and is at the top. The long leg runs parallel to the side surface of the tape guide frame 9 and is pivoted on it by the bearing pin 13 . The short leg covers the left half of the tape guide channel 24, the particular in the enlarged view of the 12 and 13 can be seen. The right half of the tape guide channel 24 is covered by an opposite flap 12, which is formed as a mirror image of the flap 11 and is held at the opposite end of the bearing pin 13 so that it can pivot. Each flap 11, 12 is pivotally attached to the tape guide frame 9 by the ends of two pivot pins 13. As shown in FIG.

The 6 FIG. 12 shows a view of the tape guide frame 9 cut along the section line VI-VI 4 . The section line VI-VI runs through a magnetic closing part 14 which is arranged in the center of the flap 11. The opposite flap 12 also has a magnetic closing part 15 in its center. The Figures 4 to 6 show the flaps 11 and 12 in a closed position. In this closed position, the two magnetic closing parts 14, 15 of the flaps 11, 12 are aligned with a steel bolt 16 which is arranged in the tape guide frame 9 between the flaps 11, 12 so as to be displaceable. The steel bolt 16 is ferromagnetic and exerts a magnetic closing force on the adjacent magnetic closing part 14 or 15 . The magnetic closing parts 14, 15 are permanent magnets in practice. For each of the magnetic closure parts 14, 15, the steel bolt 16 forms a complementary magnetic closure part. The polarity of the magnetic closing parts 14,15 is to be chosen so that both sides of the steel bolt 16 a sufficiently large closing force is generated. For this purpose, the two surfaces of the magnetic locking parts 14, 15 facing the steel bolt 16 preferably have opposite polarity.

Below in connection with the Figures 12 and 13 enlarged views of Figures 5 and 6 explained, which reveal the structure of the tape guide frame 9 in particular.

The Figures 7 to 9 correspond to the Figures 4 to 6 , but show the flap-shaped closing elements 11, 12 in the open position. In the tape guide frame 9, a plastic strip 17 is slidably mounted, in which a plurality of steel bolts 16 are embedded. Each steel bolt 16 forms a ferromagnetic closing part and is associated with a pair of permanent magnetic closing parts 14, 15 which in turn are each attached to a closing element (flap) 11 and 12, respectively. The plastic strip 17 can be displaced in the longitudinal direction of the strap guide frame 9 and forms a displacement means for the sliding, ferromagnetic closing part 16. An opening magnet 18 is arranged on the plastic strip 17 in the longitudinal direction of the strap guide frame 9 adjacent to the steel bolt 16 and forms an opening part of the magnetic closing device. An opening magnet 18 is assigned to each steel bolt 16 . In 7 It can be seen that the plastic strip 17 is shifted in the open position in such a way that the opening magnet 18 is aligned with the two fixed, magnetic closing parts 14 and 15 . The opening magnet 18 has such a polarity that the same poles of the magnetic closing parts 14, 15 and the opening magnet 18 face each other. The opening magnet 18 consequently repels the magnetic closing parts 14 and 15 and moves the flaps 11, 12 to the open position, which is shown in Figures 8 and 9 can be seen. In this open position the strap guide channel is completely open and a strapping strap held in the strap guide channel can emerge from the strap guide channel without touching one of the closing elements (flaps 11,12).

The figures 10 and 11 show a corner area of the tape guide frame 9, which is 3 is marked as detail X. In 11 Two ends of the plastic strips 17 of two mutually right-angled legs of the tape guide frame 9 can be seen. In the 11 the adjusting drive for two plastic strips 17 can be seen. Each plastic strip 17 is coupled to a rotatably mounted drive pulley 20 via a drive rod 19 . As in 10 As can be seen, the drive pulley 20 is moved by a drive motor 21 with a slipping clutch 22 into two discrete positions, namely the open position and the closed position. The plastic strips 17 are also shifted into the open position or the closed position via the drive rods 19, in which on the one hand the opening magnets 18 as opening parts are opposite the magnetic closing parts 14 and 15 of the flap-shaped closing elements 11, 12 and on the other hand the steel bolt 16 on the plastic strip 17 the magnetic Closing parts 14, 15 of each flap 11, 12 opposite, the steel bolt forming a ferromagnetic closing part for each of the two closing elements 11, 12.

The plastic strip has oblong holes 25 for receiving the bearing pins 13 which guide and fasten the plastic strip 17 to the tape guide frame 9 . The pierced by the bearing pins 13 slots 25 of the plastic strip 17 are in z 11 to recognize.

In detail, the structure of the tape guide frame in the Figures 12 - 13 to recognize. The structural strength of the tape guide frame 9 is ensured by a rectangular hollow profile 23 made of sheet metal, which surrounds the plastic strip 17 and in which the plastic strip 17 is slidably received. A U-shaped cover profile 26 is arranged on the outside of the hollow profile 23 and covers the outside of the hollow profile 23 and the bearings for the flaps 11, 12 in a protective manner. On the inside of the hollow profile 23 pointing towards the inside of the strap guide frame 9 there is a strap guide profile 27 made of plastic, the surface of which pointing into the inside of the strap guide frame forms the guide surface 28 for the strapping strap 2 . The strap 2 is in the figure 12 and 13 to recognize. In order to keep the friction between the strapping band 2 and the guide surface 28 as small as possible, the guide surface 28 has webs 30 which are interrupted by grooves 29 and which form the support for the strapping band 2 . The flaps 11, 12 and 13 are made of plastic and lie laterally against the side walls of the tape guide profile.

It can be seen that the flaps 11, 12 are closed by moving the plastic strip 17 from the open position to the closed position and the flaps 11, 12 are opened by moving it from the closed position to the open position. For this purpose, the plastic strip 17 is in the open position in relation to the magnetic closing parts 14, 15 of the flaps 11,12 in such a way that one opening magnet 18 is aligned with the opposite magnetic closing parts 14,15 and between the opening magnet 18, which forms the opening part, and the closing parts 14, 15 an opening force arises because each end of the opening magnet 18 is opposite an end of a magnetic closing part 14,15.

A person skilled in the art can see that the opening magnet 18 on the plastic strip 17 can be omitted. In this case, no opening force is generated when the plastic strip 17 is moved into the open position, but the flap-shaped closing element 11, 12 is held without force on the tape guide frame 9, because each magnetic closing part 14, 15 is opposite a non-magnetic plastic section of the plastic strip 17.

In the closed position, on the other hand, the ferromagnetic steel bolt 16 is opposite the magnetic closing parts 14,15, so that the closing parts 14,15 are magnetically attracted.

It is also recognizable for the person skilled in the art that the displacement of the plastic strips 17 or the displacement of the steel bolts 16 as the ferromagnetic closing part or the opening magnet 18 as the opening part other than can be effected by a drive motor. The displacement can be generated by any other actuator or linear motor, for example a solenoid linear motor. It is also possible to use the magnetic force that prevails between the magnetic closing parts 14, 15 on the flaps 11, 12 and the magnetic closing part on the plastic strip 17 to move the plastic strip in 17 into the closed position. In this closed position, the closing parts attract each other, so that this magnetic force causes the moving plastic strip to move into the closed position.

The Figures 14 and 15 12 show a section cut through the bearing pins 13 of an alternative embodiment of a tape guide frame whose closing elements 11', 12' have an integrated tape path. The closing elements 11', 12' are in turn designed as an L-shaped pivotable flap. Each of the closing elements 11', 12' has a leg 111,121 which projects towards the center of the tape guide frame and which fits into the Figures 14 and 15 is at the top and runs horizontally. Each of these legs 111, 121 has a gap 113, 123 which opens into the respective free end face 112, 122 of the horizontal leg 111, 121. The free end faces 112, 122 adjoin one another in the channel-closing position of the closing elements 11', 12', so that the two opposing gaps 113, 123 together form the tape guide channel (see Fig. 14 ). When the flap-shaped closing elements 11', 12' swing open, the gaps 113, 123 move away from each other and expose the strapping band 2 lying between them (see Fig. 15 ). The corner elements of the tape guide frame may have similar flap-shaped closure elements, but with the gaps having a curved course along an arc of a circle of 90° and forming a curved section of the tape duct.

The features of the invention disclosed in the present description, in the drawings and in the claims can be essential both individually and in any combination for the realization of the invention in its various embodiments. The invention is not limited to the described embodiments. It can be varied within the scope of the claims and taking into account the knowledge of the person skilled in the art.

Reference List

1

strapping machine

2

strapping

3

supply roll

4

retraction device

5

tape magazine

6

Belt conveyor device, belt drive

7

Object

8th

clamping device

9

tape guide frame

10

closure unit

11,11'

closing element, flap

12,12'

closing element, flap

13

bearing pin

14

magnetic locking part

15

magnetic locking part

16

Steel bolt, locking part

17

Plastic strip, means of displacement

18

Opening magnet, opening part

19

drive rod

20

drive pulley

21

drive motor

22

slip clutch

23

hollow profile

24

tape guide channel

25

Long hole

26

cover profile

27

tape guide profile

28

guide surface

29

groove

30

web

111

leg protruding towards the center of the tape guide frame

112

free face

113

gap

121

leg protruding towards the center of the tape guide frame

122

free face

123

gap

Claims (12)

1. A strapping machine (1) comprising a strap guide frame (9) having a strap guide channel (24) and a plurality of closing elements (11, 12; 11', 12') which are arranged in a distributed manner over the length of the channel and which can be moved from a position closing the channel into a position opening the channel counter to a restoring force, wherein the closing elements (11, 12; 11',12') can be fixed in the position closing the channel via a closing force which is generated by a magnetic closure device, wherein the magnetic closure device has two closing parts (14, 16; 15, 16) which interact with one another and attract each other magnetically, of which one (14; 15) is fastened to a closing element (11; 12) and the other (16) is fastened to the strap guide frame (9), characterized in that the magnetic closure device has a displacement means (17) for displacingthe closing part (16) fastened to the strap guide frame (9), as a result of which the closing force is canceled or an opening force directed counter to the closing force is generated.
2. The strapping machine (1) as claimed in claim 1, characterized in that the closing elements (11, 12; 11',12') are flap-shaped and are fastened pivotably to the strap guide frame (9) and cover the strap guide channel (24).
3. The strapping machine (1) as claimed in claim 1 or 2, characterized in that one of the closing parts (14; 15) is permanent-magnetic and the other closing part (16) is either permanent-magnetic or ferromagnetic.
4. The strapping machine (1) as claimed in any one of the preceding claims, characterized in that the displacement means (17) displaces the displaceable closing part (16) from a closing position close to the stationary closing part (14; 15) into an opening position remote from the stationary closing part (14; 15).
5. The strapping machine (1) as claimed in claim 4, characterized in that the magnetic closure device has an opening part (18) which, in the opening position, lies close to a closing part (14, 15), wherein this closing part (14; 15) and the opening part (18) are permanent-magnetic and identical poles of the closing part (14, 15) and the opening part (18) face one another.
6. The strapping machine (1) as claimed in any one of the preceding claims, characterized by at least one of the following features:

   the magnetic closure device has at each closing element (11, 12; 11',12') a closing part (14, 15) and a second closing part (16) assigned to this closing part (14,15) and fastened to the strap guide frame (9);

   the displacement means (17) is fastened to the strap guide frame (9);

   the displacement means (17) has an actuating drive (19-22).
7. The strapping machine (1) as claimed in claim 6, characterized in that the actuating drive (19-22) generates an opening force with which the displaceable closing part (16) is displaced into the opening position, and that the closing parts (14, 15, 16) which interact with one another generate a closing force with which the displaceable closing part (16) is displaced into the closing position.
8. The strapping machine (1) as claimed in any one of preceding claims 2 to 7, characterized in that each of the two opposite and pivotable closing elements (11', 12') has a limb (111, 121) which projects toward the center of the strap guide frame, where two free end faces (112, 122) of these limbs (111, 121) adjoin one another in the position closing the channel and wherein each of these limbs (111, 121) has, proceeding from the respective free end face (112, 122), a gap (113, 123) and the gaps (113, 123) which lie opposite one another jointly form the strap guide channel.
9. A method for strapping items with a strapping machine (1) as claimed in claim 1, characterized in that, by displacing the closing part (16) fastened to the strap guide frame (9) by means of the displacement means (17), the closing force is canceled or an opening force directed counter to the closing force is generated.
10. The method as claimed in claim 9, characterized in that the displaceable closing part (16) is displaced from a closing position close to the stationary closing part (14; 15) into an opening position remote from the stationary closing part (14; 15).
11. The method as claimed in claim10, characterized in that the magnetic closure device has an opening part (18) which, in the opening position, lies close to one of the closing parts (14; 15), wherein this closing part (14; 15) and the opening part (18) are permanent-magnetic and identical poles of the closing part (14; 15) and the opening part (18) face one another.
12. The method as claimed in any one of claims 9 to 11, characterized in that an actuating drive generates an opening force with which the displaceable closing part (16) is displaced into the opening position and that the closing parts (14; 15, 16) which interact with one another generate a closing force with which the displaceable closing part (16) is displaced into the closing position.

Images