EP3798145B1 - Fastening means for strap channel of a strapping machine - Google Patents

Description

The invention relates to a strapping machine with a strap guide frame which has a strap channel for a flat strap, according to the preamble of patent claim 1.

Tape guide frames are part of a strapping machine for strapping objects such as stacks of newspapers, packages or the like using a flat strap. The objects are usually transported on a conveyor into the belt guide frame so that they protrude through the plane of the belt guide frame. A flat strap is fed into the strap channel in the strap guide frame by the strap drive. The tape guide frame is then opened, the tape loop formed being released in the radially inward direction and surrounding the object to be strapped. The strap loop is then tightened until it is tight about the item to be strapped. In this state, the formed loop of tape is separated from the supply of tape, and the two ends of the loop of tape are pressed against and connected to each other. The loop ends are usually connected by welding. The strap guide frame has a flat strap channel that is open on a narrow side, from which the strap exits. The open strap channel is covered while the strap is being fed in. A relative movement between the sliver duct and the cover exposes the narrow side of the sliver duct.

The pamphlet WO 2008/019991 A1 describes a strap guide frame for a strapping machine, which has a flat strap channel, an opening device being arranged on the strap guide frame which opens a narrow side of the flat band channel by actuating at least one movable cover element which, in a closed position, covers the narrow side of the band channel and, in an open position, releases the narrow side of the band channel. At least one ejector is arranged on the strap guide frame, which pushes the strap loop formed in the strap channel through the open narrow side out of the strap channel when the opening device is in the open position.

Strapping machines with strap guide frames composed of corner elements and straight elements connected to each other, each corner element having a curved portion of the strap channel and each straight element having a straight portion of the strap channel, are e.g. from the references JP S53-57 088 U , U.S. 3,572,237 A and EP 0 223 988 B1 known. The frame elements are usually not designed as load-bearing components. The strapping machine has a support frame that is made, for example, from sheet metal that is several millimeters thick. The frame elements are usually attached to this support frame with screws.

From the pamphlet JP 2000 - 203 514 A a strapping machine with a fastening clip is known according to the preamble of claim 1. The fastening clip has a back section, which is followed by two mutually parallel legs. One leg of the fastening clip has a retaining projection at its end, which engages behind an edge of a groove in a first side surface of the element in a form-fitting manner. The second leg of the fastening clip has a holding projection which positively engages behind an edge of a groove in a second, opposite side face of the element. The back portion of the mounting clip is fastened with nuts to a threaded rod which in turn is fastened to the frame with nuts. Such a fastening is complicated and expensive to manufacture.

the JP S49 - 146 087 U on the other hand, discloses a mounting clip that simultaneously engages around a member of the tape guide frame and a support rod. Here the element of the strap channel is designed with resilient elements which swing open when the strapping strap is pulled out of the strap channel. A support frame made of sheet metal for the sliver channel is in the JP S49 - 146 087 U not provided. From the EP 0 223 988 spring detents are known for securing two members of the tape leader frame together. the JP S53 - 57 088 U describes screw fastenings for frame elements.

The object of the invention is to simplify the fastening means for the frame elements and, in particular, to enable flexible production of different frame sizes.

This object is achieved according to the invention by the features of patent claim 1 in their entirety.

As mentioned above, the frame elements are usually fastened by means of a screw connection. A screw connection is one of the most common types of connection. It is inexpensive, very durable and easy to assemble. It is necessary for the components that are screwed together to be matched to one another. Screw holes in one component must line up with screw holes in another component. Additional parts such as washers and nuts are often required.

It is also known to at least partially attach the frame elements to the support frame by means of resilient attachment clips. This results in an inexpensive and simple attachment of the parts, which can be used quite flexibly. In particular, there is flexibility when the frame elements in question have grooves into which the locking projections of the fastening clips snap. The mounting clips can then be placed at different locations along the length of the frame members are arranged so that a flexible mounting position of these frame members can be achieved. However, the screw fastening of the frame elements is again quite complex and requires various separately manufactured fastening elements.

It is now proposed, by means of a fastening clip, which consists of a back section and two legs parallel to one another, the ends of the legs latching into grooves in the side surfaces of the element of the belt guide frame, not only to connect to the frame element but also to the support frame made of folded sheet metal produce. For this purpose, the support frame has at least one opening through which the fastening clip protrudes, so that the side of the back section facing the element rests against the support frame and thus fixes the element to the support frame.

In other words, the fastening clip, the support frame and the element of the tape guide frame are matched to one another such that the fastening clip latches onto the frame element and not only fixes the frame element but also creates the connection between the fastening clip and the support frame. The essentially U-shaped protrudes through an opening in the sheet metal of the support frame and lies with the side of the back section facing the frame element against the sheet metal of the support frame. By snapping into the grooves of the element of the tape guide frame, this element is thus fixed to the fastening clip and to the support frame at the same time.

The constructive solution of allowing the fastening clip to latch with grooves running in the longitudinal direction of the frame elements enables relative movements between the frame element and the support frame. These relative movements avoid stress or deformation due to temperature changes. With a support frame made of metal and frame elements made of plastic, different expansions occur when the temperature changes. On the one hand, these expansions can be compensated for by the spring-loaded fastening clips, because their resilient material section can follow the deformation of the frame elements and possibly the support frame. On the other hand, the frame element can be shifted in the longitudinal direction to the fastening clip and thus also move relative to the support frame, because the holding projections of the fastening clips can be displaced in the grooves of the frame elements.

In practice, the back portion of the fastening clip can be curved so that it elastically draws the element of the tape guide frame towards the support frame. The fastening clip consists of an essentially U-shaped sheet metal strip. At its two ends are the projections that engage with the grooves of the frame member. The intermediate section of the sheet metal strip, which forms the back section, is curved, with its curvature being convex towards the frame element and towards the supporting frame clamped between the frame element and the back section. When the projections engage in the grooves of the element, the sheet metal strip that forms the fastening clip is bent in the area of the concave curvature, so that the projections elastically pull the element against the supporting frame and press both firmly against one another.

In practice, only one leg of the fastening clip can protrude through the opening in the support frame. However, both legs can also be guided through openings. The openings in the material of the support frame can be closed bores but also recesses.

In practice, the joined elements of the tape guide frame may comprise corner elements and straight elements connected together, each corner element having a curved section of the belt channel and each straight element having a straight section of the belt channel. Such a construction offers a particular advantage, namely that any frame size can be realized in a simple manner. The elements can be standard elements that have the same structure for every corner and for every frame size. The straight elements can be cut to the required length and placed between two corner elements. In this way, a series of strapping machines of different sizes can be implemented with very simple means.

In practice, the straight elements can be fixed to the support frame by means of fixing clips. The corner elements can be bolted to the support frame in a conventional manner. To vary the frame size, it is sufficient to be able to change the length of the frame legs. The curve radius, on the other hand, does not have to be varied. It can be consistently implemented with standard corner components that have proven themselves in practice.

As mentioned, the fastening clips engage behind the contour of the element fastened with them in a form-fitting manner. In other words, the frame elements, which are fastened with fastening clips, can have grooves in which latching elements of the fastening clips engage in a form-fitting manner. In particular, the straight elements can have mutually opposite side surfaces on which grooves running in the longitudinal direction are arranged. The fastening clips have holding projections which engage in the grooves. The straight elements with the grooves and the straight section of the belt chute can be made from an extruded profile. It is therefore possible to create long profiles, from which the straight elements are made, in a proven and cost-effective manufacturing process of extrusion. In their cross-section, these profiles have grooves on opposite side surfaces, in which, if necessary, catch engages behind. Furthermore, these profiles have a slot that forms the tape guide channel. The support frame has openings through which the fastening clips protrude, which connect the support frame and the straight element to one another in a clipping process. The extruded profiles can be manufactured or cut to the specified length so that the belt guide frame can be manufactured in the correct size to meet the requirements.

In practice, the corner elements can have indentations on the end faces, into which the ends of a straight element can be inserted, so that the sections of the sliver channel in the corner elements and the straight elements are aligned with one another. In other words, recesses are attached to the end faces of the corner elements, which recesses each receive one end of a straight element in such a way that the band channel sections in the corner element and the straight element are aligned with one another. This ensures that the frame elements are securely connected to one another, even if there is a certain amount of play between consecutive frame elements due to manufacturing tolerances or thermal expansion.

In practice, the corner elements can be connected to the supporting frame by means of fastening screws. Fastening screws ensure that the corner elements are dimensionally stable. This is important for strapping machines because incorrectly aligned corner elements can lead to strapping malfunctions. In particular, the support frame can have at least one holding opening through which a holding projection of a corner element protrudes and engages, with an internal thread being arranged at a distance from this holding opening, into which a fastening screw protruding through the corner element is screwed. In the case of a support frame made of sheet metal, openings can be made particularly easily by laser cutting. Pushing through a form-fitting retaining projection and screwing the corner elements into place ensures a firm connection to the support frame.

Fig. 1

zeigt eine schematische Vorderansicht einer Umreifungsmaschine.

Fig. 2

zeigt eine Vorderansicht eines erfindungsgemäßen Tragrahmens mit Bandkanal.

Fig. 3

zeigt den Ausschnitt A aus Figur 2 in vergrößerter Darstellung.

Fig. 4

zeigt die Rückansicht des Tragrahmens aus Figur 2.

Fig. 5

zeigt ein entlang der Schnittlinie V-V geschnittene Darstellung des Tragrahmens aus Figur 4.

Fig. 6

zeigt eine vergrößerte Darstellung der Einzelheit B aus Figur 5.

Fig. 7

zeigt eine vergrößerte Darstellung der Einzelheit C aus Figur 4.

Fig. 8

zeigt eine vergrößerte Darstellung der Einzelheit D aus Figur 5.

Fig. 9

zeigt eine vergrößerte Darstellung der entlang der Schnittlinie IX-IX in Figur 4 geschnittenen Darstellung.

Fig. 10

zeigt eine linke obere Ecke einer alternativen Ausführungsform eines Tragrahmens.

Fig. 11

zeigt eine entlang der Schnittlinie XI-XI geschnittene Darstellung des Tragrahmens aus Fig. 10.

Fig. 12

zeigt eine vergrößerte Darstellung der Einzelheit E aus Figur 11.

Fig. 13

zeigt eine dreidimensionale Darstellung eines Abschnitts eines geraden Elements mit Bandkanal.

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

1

shows a schematic front view of a strapping machine.

2

shows a front view of a support frame according to the invention with a sliver channel.

3

shows section A figure 2 in an enlarged view.

4

shows the rear view of the support frame figure 2 .

figure 5

shows a representation of the support frame cut along the section line VV figure 4 .

6

shows an enlarged view of the detail B from figure 5 .

7

shows an enlarged view of detail C from figure 4 .

8

shows an enlarged view of detail D from figure 5 .

9

shows an enlarged view of the along the section line IX-IX in figure 4 cut representation.

10

Figure 12 shows an upper left corner of an alternative embodiment of a support frame.

11

shows a representation of the support frame cut along the section line XI-XI 10 .

12

shows an enlarged view of detail E from figure 11 .

13

Figure 12 shows a three dimensional representation of a section of a straight ligament channel member.

The one in the figure 1 The strapping machine 1 shown is used to strap objects 7 with a strap 2, which is pulled from a supply roll 3 by a pull-in device 4, and a strap magazine 5 is supplied. From there, the strap is fed by a strap conveyor device 6 through a tensioning device 8 to a strap channel in 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 foil-like plastic material from which the strapping band 2 is made. The conveyor that transports the item 7 in and out of the strapping zone within the strap guide frame 9 is in figure 1 not shown.

In figure 1 only an outer protective frame of the tape guide frame 9 can be seen. Inside the outer protective frame there is a support frame 11 on which the elements of the tape guide frame 9 with the tape channel and closing devices for the tape channel and ejectors 17 are arranged. A support frame 11 according to the present invention is in figure 2 shown in front view. It is made from sheet steel by folding and laser cutting. Such a steel sheet typically has a thickness of 3 to 6 mm.

Corner elements 12 and straight elements 13 are fastened to the support frame 11 . An enlarged view of the corner element 12 and the end portions of two straight elements 13 connected thereto is shown in FIG figure 3 shown. The corner member 12 includes a curved portion 14 of the ligament channel. Each straight element 13 comprises a straight section 15 of the ligament channel. It should be noted that the front ends of the curved portions 14 and straight portions 15 of the tape chute in the tape conveying direction each have a funnel-shaped extension 16 . This funnel-shaped extension 16 facilitates the entry of the sliver conveyed through the sliver channel at high speed into the next section 14, 15 of the sliver channel.

In the middle of the corner element 12 there is an ejector 17 designed as a long, pivotable arm, with which the strap can be ejected from the curved section 14 of the strap channel.

the figure 4 shows the back of the support frame 11. The support frame 11 has a plurality of mounting openings 18 with which the support frame 11 can be attached to the outer protective frame. In figure 4 only two of the mounting openings 18 are provided with a reference number.

Furthermore, fastening clips 19 can be seen at regular intervals on the back of the supporting frame 11, with which the straight elements 13 are fastened to the supporting frame 11. the figure 5 shows a sectional view according to section line VV in figure 4 . It can be seen that the sheet metal of the support frame 11 is bent and has a horizontal leg 20 which stiffens the support frame 11 . Details from the figures 4 and 5 are in the Figures 6 to 8 shown enlarged.

the figure 6 shows a sectional view of the fastening clip 19. The fastening clip 19 fastens a straight element 13 with a straight section 15 of the belt guide channel to the supporting frame 11. For this purpose, the supporting frame 11 has an opening 21 through which the fastening clip 19 protrudes. The fastening clip 19 consists of a sheet metal strip bent over in a substantially U-shape. It has a back section 22 to which two mutually parallel legs 23, 24 are connected. The leg 23 of the fastening clip 19 protrudes through the opening 21 of the Support frame 11 and has at its end an angled retaining projection 25 which engages behind the edge of a groove 26 in a first side surface 27 of the straight element 13. The second leg 24 of the fastening clip 19 has a resilient holding projection 28 which engages behind an edge of a groove 29 in the second side face 30 of the straight element 13 . The back section 22 of the fastening clip is arched so that it draws the straight element 13 of the tape guide frame 9 elastically towards the support frame 11 . The curvature of the back section 22 extends convexly in the direction of the two legs 23, 24. The curved back section 22 rests against the section of the support frame 11 next to the opening 21. To lock the two retaining projections 25 and 28 in the grooves 26 and 29 of the straight element 13 of the tape guide frame, the arched back section 22 is bent up slightly so that, after locking, it presses the section of the support frame 11 and the straight element 13 together with an elastic clamping force .

It can be seen that the fastening clips 19 can be used to fasten the straight element 13 of the tape guide frame 9 very quickly, inexpensively and reliably. The straight element 13 can be made from an extruded profile made of plastic or light metal, which has essentially the same profile cross section over its length. It has grooves 26, 29 on the mutually parallel side surfaces 27, 30, which can be used to interact with the fastening clips 19 at any desired location. Furthermore, the profile of the straight element 13 has a straight section 15 of the belt guide channel.

the figure 9 shows schematically the fastening of the corner element 12 in a corner of the support frame 11. For this purpose, the metal sheet of the support frame 11 has a retaining opening 31, through which a hook-shaped retaining projection 32 of the corner element 20 protrudes, the hook-shaped retaining projection 32 touching the edge of the retaining opening 31 behind.

Furthermore, the corner element 12 is fixed by a fastening screw 33 which is screwed into an internal thread in the sheet metal material of the support frame 11 . The corner element 12 is securely fastened to the support frame 11 by this simple method of attachment.

the Figures 10 to 12 show an alternative construction of the support frame 11'. Here the opening 21', through which a leg 23 of the fastening clip 19 extends, is arranged in the horizontal leg 20' of the support frame 11'. The straight element 13 is not only pulled against the rear side of the support frame 11' by the fastening clip 19, but also against its horizontal leg 20' and is thereby additionally stabilized.

the figure 13 13 shows a three-dimensional representation of the profile of the straight element 13. The straight section 15 of the tape guide channel with the funnel-shaped expansion 16 at one end can be seen. Furthermore, the grooves 26, 29 can be seen in two opposite, parallel side surfaces 27, 30 of the straight element 13, by means of which the straight element 13 can be fixed at any point by a fastening clip 19 on the support frame 11. The straight element 13 can be cut to the required length and fastened with the fastening clips 19 on the support frame 11, 11' between two corner elements 12.

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 embodiments described. 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'

supporting frame

12

corner element

13

straight item

14

curved section

15

straight section

16

funnel-shaped expansion

17

ejector

18

mounting hole

19

mounting clip

20, 20'

horizontal leg

21,21'

opening

22

Back section of the mounting clip

23

Leg of the mounting clip

24

Leg of the mounting clip

25

retaining projection

26

groove

27

side face

28

resilient retaining projection

29

groove

30

side face

31

holding hole

32

retaining projection

33

mounting screw

Claims (10)

1. A strapping machine (1) comprising a strap guide frame (9) having a strap channel for a flat strap (2), wherein the strap guide frame (9) comprises a plurality of elements (12, 13) joined to each other, each element (12, 13) having a portion of the strap channel and being attached to a support frame (11), at least some of the elements (13) being fastened to the supporting frame (11) by means of resilient fastening clips (19), and the fastening clip (19) having a back portion (22) which is adjoined by two mutually parallel legs (23, 24), one leg (23) of the fastening clip (19) having at its end a retaining projection (25) which positively engages behind an edge of a groove (26) in a first side face (27) of the element (13), and the second leg (24) of the fastening clip (19) having a retaining projection (28) which positively engages behind an edge of a groove (29) in a second side face (30) of the element (13), characterized in that the supporting frame (11) is made of folded sheet metal and has at least one opening (21) through which the fastening clip (19) projects, so that the side of the back portion (22) facing the element (13) rests against the supporting frame (11) and thus fixes the element (13) to the supporting frame (11).
2. Strapping machine (1) according to claim 1, characterized in that the back portion (22) of the fastening clip (19) is curved so as to elastically pull the element (13) of the strap guide frame toward the supporting frame (11).
3. Strapping machine (1) according to claim 1 or 2, characterized in that at least one leg (23) of the fastening clip (19) projects through the opening (21) of the supporting frame (11).
4. Strapping machine (1) according to claim 1, 2 or 3, characterized in that the joined elements of the strap guide frame comprise corner elements (12) and straight elements (13) joined to one another, each corner element (12) having a curved portion (14) of the strap channel and each straight element (13) having a straight portion (15) of the strap channel.
5. Strapping machine (1) according to claim 4, characterized in that the straight elements (13) are fixed to the supporting frame (11) by means of fastening clips (19).
6. Strapping machine (1) according to claim 4 or 5, characterized in that the straight elements (13) have opposing side faces (27, 30) on which longitudinally extending grooves (26, 29) are arranged, and in that the fastening clips (19) have retaining projections (25, 28) which engage in the grooves (26, 29).
7. Strapping machine (1) according to claim 6, characterized in that the straight elements (13) are made of an extruded profile.
8. Strapping machine (1) according to one of the preceding claims 4 to 7, characterized in that the corner elements (12) have recesses at the end faces, into which recesses the ends of a respective straight element (13) can be inserted, so that the sections of the strap channel in the corner elements (12) and the straight elements (13) are aligned with one another.
9. Strapping machine (1) according to any of the preceding claims 4 to 8, characterized in that the corner elements (12) are connected to the supporting frame (11) by means of fastening screws (33).
10. Strapping machine (1) according to claim 9, characterized in that the supporting frame (11) has at least one retaining opening (31) through which a retaining projection (32) of a corner element (12) projects and is engaged behind, and in that an internal thread is arranged at a distance from this retaining opening (31), into which internal thread a fastening screw (33) projecting through the corner element (12) is screwed.

Images