MXPA98009891A - Appliance to flejar paque - Google Patents

Abstract

An apparatus for strapping packages with a band (7) made of weldable plastic, composed of a belt supplying unit, a belt conveyor and tensioner unit, a belt conveyor and tensioning unit, a closing unit, which is provided as a separate unit, and has a stop plate, and a band guiding unit and has at least one band clamp (15) with a clamped clamp part mounted with pivoting movement (10). The clamp of the band (15) is formed by a specific recessed section (14) in the stop plate (5) and the clamping part (10), a curved operating surface (40) that is provided on the part of the clamp (10). clamping, and band clamp (15) that are automatically secured. In making the selection that the clamping angle W of the band clamp (7), between the clamping part (10) and the recessed section (14), be as long as possible, it will mean that the release of the clamp of the band is easier when the band is tensioned. The apparatus makes it possible for the strip strips to be applied, even with the application of a high voltage, without slipping during the closing operation.

Description

Apparatus for Filing Packs The invention relates to an apparatus for strapping packages with a band, in particular made with a weldable plastic, having a band supplying unit, a conveyor and band tensioning unit, a closing unit, which is provided as a separate unit and has a stop plate, and a guide unit for the band according to the preamble of the patent in claim 1. The apparatus for strapping packages with weldable plastic bands, in particular the apparatus in which The closure unit is provided as a separate unit, they are already known through a large number of publications. The methods of closure used in these cases are usually welding methods such as friction welding or welding through elements of welding tongs. Thus, for example, in CH-A-686 079 a disclosure is made on an automatic device for binding packages with a closing unit of the aforementioned type, in this case there is a first and second device for clamping arranged directly under a sliding plate which can be moved from back to front. This sliding plate serves to absorb the force when the plastic band is firmly clamped during the closing operation, but is moved to move it away after concluding the closing operation with it. order to release the package. The devices for clamping are toothed parts that can be moved downwards and upwards, or with other suitable shapes for clamping the plastic band between the movable parts and the sliding plate. In DE-A-44 25 908, DE-A-40 14 307 and EP-0 490 477 the disclosure of clamping devices of similar construction is made. In the case of all these apparatuses, the clamping action of the device for clamping is achieved through a translation movement of the clamping part. Devices of this type have the disadvantage that, with a high application of tension there is a risk that the plastic band will slip when it is firmly clamped. US-A-011 807 and EP-A-0 099 606 disclose apparatuses with clamping parts, mounted with pivoting movement with curved operating surfaces. However, also in the case of these apparatuses there is a risk that when applying a high tension, the plastic band slips when it is firmly clamped with the clamp. The object of the invention is to specify an apparatus for strapping packages which ensures that, even at high tension, the strapping band does not slip. This object is obtained according to the invention, according to Claim 1 of the patent, making use of band clamps with automatically insurable parts, fixed with pivoting movement. The band clamps with clamping parts mounted with pivoting movement can be designed in a non-bending manner such that they are automatically secured and thus produce a clamping force that is proportional to tension. Use is preferably made in this case of parts for clamping with curved operating surfaces, which, in order to increase the clamping effect, can be provided with a fine tooth arrangement. The curvature of the operative surfaces, in this case, can be cylindrical, that is, they can be constant with a radius, but it is also possible to use curves with variable curvatures. In a particularly advantageous configuration, the clamping parts with curved operating surfaces are designed in such a way that they are also easier to release when the band is tensioned. For this purpose, on the one hand, the band clamps are configured in such a way that the range of the angle covered by the curved operating surface is selected to be as long as possible, and on the other hand, the clamp of the band is formed, in the actual clamping region, in such a way that the point or the fixing area of the main active clamping force changes direction, during a pivoting movement of the clamping part, on the operative surface of the clamping part in a direction opposite to the pivoting movement. Other advantageous embodiments of the apparatus, according to the invention, are explained in greater detail in the following description. These relate, inter alia, to the arrangement of a closure plate and to the pivoting arrangement of the welding tongs and to a band saw. Taken as a whole, the features mentioned in the patent claims allow a particularly compact and straight construction of an apparatus that is designed to strapping packages and that also operates reliably and safely with the application of tension force up to 4000 N An exemplary embodiment of the invention will be explained in more detail with reference to the drawings in which: Figure 1 shows a schematic illustration of the strapping apparatus, Figure 2 shows the closing unit during the advancement of the band, Figure 3 shows the closing unit while the band is pulled back and tensioned, Figure 4 shows the closing unit during the closure of the band, Figure 5 shows the closing unit during the release of the strip , Figure 6 shows the clamp of the band before starting the tension application operation, and Figure 1 shows a Band clamp at the end of the tensioning operation. Figure 1 shows a schematic illustration of the apparatus for strapping packages 1. The apparatus is essentially composed of a band supplying unit 2, a conveyor and band tensioning unit 3, a closing unit 4, with a stop plate 5, and a guide unit of the band 6 for guiding the band 7. Figure 2 shows a front view and a side view of the closure unit 4 during the first phase of the band operation, namely the feeding of the band 7. The band 7 is first pushed completely through the closing unit 4, which is located in the initial position, in direction A through the conveyor unit of the belt and the tension application unit 3 and continues to be pushed through the band guiding unit 6 (see Figure 1) until finally, it comes in contact with the band guiding unit ß again from the direction B. The feeding of the band 7, which is an operation controlled by a control unit (not illustrated), is performed first between the stop plate 5 and the first clamping part 10 and then between the stop plate 5 and a band cutter 11, the band cutter 11 carries the mechanism of interruption 12 which sends the signal to conclude the feeding of the band. The first clamping part 10, which is pivotally mounted around a first pivot shaft 13, forming together with the stop plate 5, has a first formed section 14, and a first band clamp 15. It is also provides a second clamping part 16, which is mounted with pivoting about a second pivot axis and next to the stop plate 5, which has a second section 18 formed, forming a second band clamp 19. The first band clamp 15 serves to clamp securely the end of the band that is pushed in before tension is applied to the band 7 through the elements of the conveyor and belt tensioning unit. The second band clamp 19 similarly serves to securely clamp the band with tension, on the opposite side, before the band is welded and cut. The band clamps referring to Figures 6 and 7 are described below in greater detail. The first clamping band 10 is moved by a counter cutter 20, which is adapted in a slider 21. The slider 21 is driven by a plurality of eccentric disks 22, which are seated on an axis of eccentric disks 23. The second clamping part 16 is moved by a link plate 24, which is adapted on a push rod 25. The push rod 25 is also driven by an eccentric disc.

Between the push rod 25 and the slider 21 another push rod 26 is located, which is equally driven through an eccentric disc 22 and at the upper end thereof there is a closure plate 27 mounted in such a way that could be pivoted about an axis of rotation 28 contrary to a spring (not shown). In the rest position, the closing plate 27 is arranged obliquely with respect to the longitudinal extension of the stop plate 5 and is held in this position by a cutter 29. The cutter 29 is adjusted in the same way on another rod push 26. The arrangement of the closing plate 27 in the rest position facilitates the introduction of the band 7. In the operative position, the closing plate 27 can move with pivoting towards the stop plate 5 moving through the elements of another push rod 26. The stop plate 5 has a fixed connection with the casing of the pivot 30, which is adapted on the main casing 32 in such a way that it can be rotated about an axis 31. This can be observed from the side view in which the band cutter 11, which is similarly driven by an eccentric disk 22, is similarly adapted on the main casing 32 so that it can be rotated around the other In addition, welding tongs 34 for melting the bands are also driven by an eccentric disc 22 and are mounted on the housing of the pivot 30 so that they can be rotated about another axis 35. The the band 11 and the welding tongs 34 are driven in such a way that both the band cutter 11 and the welding tongs can be pivoted below the stop plate 5. Figure 3 shows a front view and a side view of the closing unit 4 during a second phase of the strap operation, in which the strip 7 is pulled back and tensioned. The first part of the clamp 10 is pushed against the first recessed section 14 of the stop plate 5 through the slider 21 and firmly clamps the tip of the band located therebetween. Subsequently, the band 7 is withdrawn backwards through the conveyor and belt tensioner unit 3 and subsequently tension is applied through a tensioning force in direction C. Figure 4 shows a front view and a side view of the unit of closure 4 during a third phase of the strap operation, in which the closure of the band 7 is performed. The second clamping portion is urged against the second recessed section 18 of the stop plate 5 through of a push rod 25 and firmly clamped the curl of the band located therebetween. After this, the operation of cutting the band and the closing operation is performed. First the cutter 29 is pushed towards the stop plate 5 through another push rod 26 and, in the process, cuts off the part of the band that is directed to the band 2 supply unit. At the same time, the plate of closure 27 is rotated about the axis of rotation 28 until it is located parallel to the stop plate 5. After this, the cutter of the strip 11 is retracted backwards respectively pivoted outwards and the welding tongs 34 are pushed respectively in inward pivoting movement, resulting in the welding tongs 34 separating to rest between the two ends of the bands. From this, another push rod 26 pushes the closing plate 27 towards the stop plate 5 and in this way the surfaces of the two ends of the band are driven to make contact with the welding tongs 34, resulting in that the surfaces of the ends of the bands are fused.

The closing plate 27 is withdrawn slightly backwards, the welding tongs 34 are withdrawn respectively with pivoting movement outwards and the closing plate 27 is extended towards the stop plate 5 with full extension, and, in the process, push the two ends of the band together to their full extent. This concludes the closing operation. Figure 5 shows a front view and a side view of the closure unit 4 during the release of the strap. Firstly, the closing plate 27 is retracted back to its full extent and the two clamps of the strip 15, 19 are released. The casing of the pivot 30 is moved away with pivot movement and releases the strap. In order to make the apparatus available for another cycle of strap, the casing of the pivot 30 is pivoted rearward again and the cutter of the strip 11 is pushed and / or pivoted down the stop plate 5 again. Figure 6 shows the first band clamp at the start of the tension application operation to the band 7. In this position the first clamping part 10 is pushed against the first recessed section 14 of the stop plate 5. , when being rotated around the first pivot axis 13, in such a way that the band 7 is clamped between one of the clamping regions. The tension force 5 acts in the direction D. The clamping part 10 has a curved operating surface 40, which can be provided with a tooth arrangement. The first recessed section 14 of the stop plate 5 has an operative surface coupled in a similar manner, and equally curved. In the following, the operating surface 40 is intended to be the section of the surface of the first clamping part 10 on which the clamped band lies. The first clamping part 10 and the corresponding first part of the recessed section 14 of the stop plate 5 are specifically designed in order to achieve an easier release. Thus, the curved operating surface 40 of the first clamping part 10 has a radius of curvature r ?, of which the center point is compensated with respect to the first pivot axis 13 and preferably a little smaller than the radius of curvature R? of the first recessed section 14. Both the curved operating surface 40 and the first recessed section 14 are preferably cylindrical and, in this case, have the radii r and R, but it is also possible to select surfaces with different curvatures in both cases. If other curvatures are selected, then the curved operating surface has (in a mathematical sense) a multiplicity (locally) of radii with different curvature r ?, where the central points of the curvature are compensated with respect to the first pivot axes 13. In order to achieve an easier release of the band clamp, the starting point will be that the band clamp is formed in the actual clamping region, such that the point or the clamping area of the clamp The mainly active clamping force rotates during the pivoting movement of the clamping portion on the operating surface of the clamping portion in a direction opposite to the movement of the pivot. This is achieved essentially through the first clamping part formed as mentioned above. If it is assumed that the aforementioned fixing point is the point at which the operating surface 40 of the first clamping part 10, in which the distance from the coupled operating surface of the first recessed section is the smallest in each and every point in time, the torsional action of the tensioning force of the band S is that which produces the clamping force mainly active Nk at this fixing point. It is assumed here that the fixing point, in the example of Figure 6, is first located on the apex of the curved operating surface 40. Finally, Figure 7 shows a band clamp after the tension force has been applied or the tensile force S to the band. The tensioning force S of the band rotates the first part of the clamping 10 in a clockwise direction through the angle A. This rotation is produced by a certain elasticity of the first band clamp 15 and of the band plastic 7, this elasticity is always present. In the example shown, the clamping point of clamping of the mainly active force rotaon the curved operating surface 40 to the left, counterclockwise.

The triangle of forces that is produced in the respective fixing points is described in Figures 6 and 7. The active forces here represent the tensioning force S of the band (tangent at the attachment point) and the mainly active clamping force with clamp N? (normal for the fixation point), it can also be taken as a measure to release the force that is applied. In this case, the following equation is valid: N? = S - co t (W?) Where? is the angle of clamping The following equation is valid for Figure 6: N = S • co t (W) Correspondingly, the following equation is valid for Figure 7: It can be seen from the geometric relationships of the triangles of forces that the angle of clamping Wx in the triangle of the forces of Figure 7 is greater than the clamping angle in the force triangle of Figure 6, and that, correspondingly, the force of release that is applied and that corresponds to clamping force N? (produced by automatic securing), decreases at the time when clamping angle? is increased. The geometrical formation of the clamping parts 10 and 16 and of the recessed sections 14 and 18 of the stop plate 5 of this embodiment are advantageously selected in such a way that the clamping angle k can be so long as possible. For this purpose, the range of the angle covered by the curved operating surface 40 of the clamping portion 10 has to be selected to be as long as possible. The curved operating surface of the clamping part is also advantageously provided with a fine-tooth arrangement, so that the clamping part is reliably gripped even in the case of a clamping angle with Clamp be long. Of course, it is also possible to provide tooth arrangements for both the surfaces of the clamping parts and for the coupled operating surfaces of the corresponding recessed sections in the stop plate. The arrangements of the moving components also allow a particularly compact and straight construction of the closing unit 4. This is achieved in particular through the arrangement of the welding tongs 34 and the band cutter 11 on the opposite sides. of the pivot case 30, it being the case that either the welding tongs 34 or the band cutter 11 are pivoted under the stop plate during the closing operation. This reduces the overall height. For the purpose of releasing the closed band 7, it is also possible that the casing of the pivot 30, with the stop plate 5, are pivoted outwards. Additionally, the construction of the closing unit shown makes it possible for operators to have greater security. The side views of FIGS. 2 to 5 show that the welding tongs 34 are widely covered by the stop plate 5 in the initial condition and are completely covered by the stop plate 5 during the welding operation and the release of the seal. band. The part of the welding tongs that comes into contact with the plastic band is always covered by the stop plate 5.

List of designations: 1. Package 2. Band supplying unit 3. Belt conveyor and tensioner unit 4. Locking unit 5. Stop plate 6. Band guide unit 7. Band 8. -9. - 10. First clamping part 11. Band cutter 12. Interrupt mechanism 13. First pivot shaft 14. First recessed section 15. First band clamp 16. Second clamping part 17. Second pivot shaft 18. Second recessed section 19. Second band clamp 20. Cutter counter 21. Slider 22. Eccentric disc 23. Eccentric disc shaft 24. Link plate 25. Push rod 26. Another push rod 27. Closing plate 28. Axis of rotation 29. Cutter 30. Pivot casing 31. Axle 32. Main carcass 33. Other axis of rotation 34. Welding tongs . Another axis 36. - 37. - 38. -39. - 40. Operational surface

Claims (9)

1. CLAIMS 1. An apparatus for strapping packages (1) with a band (7), in particular made of a weldable plastic, having a supplying band unit (2), a belt conveyor and tensioning unit (3), a closing unit (4), which is provided as a separate unit and has a stop plate (5), and a band guide unit (6), at least one band clamp (15, 19) with a clamping part mounted with a pivoting movement (10, 16) and provided with a curved operating surface (40), that band clamp (15, 19) characterized by having an automatic securing. The apparatus according to Claim 1, characterized in that between a formed section (14, 18) of the stop plate (5) and the operative surface (40) of the clamping part (10, 16), the clamp of the band (15, 19) has a region for clamping the band (7), a point or area of fixation which rotates during a pivoting movement of the clamping part (10, 16) , on the operative surface (40) of the clamping part (10, 16) in a direction opposite to the movement of the pivot, the fixing point or zone is the location or the region where the distance between the formed section (14) , 18) of the stop plate (5) and the operating surface (40) of the clamping part (10, 16) is more the small one. The apparatus, according to Claim 2, characterized by a curved operating surface (40) of the clamping part (10, 16) having at least one radius of curvature r ?, of which the central point is compensated with respect to the axis of the pivot (13, 17) of the clamping part (10, 16), and that the radius of the curvature r? is preferably less than a radius of curvature R? of the formed section (14, 18) of the stop plate (5). The apparatus of Claim 2, characterized in that the curved operating surface (40) of the clamping part (10, 16) is circular and is provided with a radius of curvature r, the radius of curvature r, is less than the radius of curvature R of the formed section (14, 18) of the stop plate (5). The apparatus according to any one of Claims 1 to 4, characterized in that the curved operating surface (40) of the clamping part (10, 16) is serrated at least in the region of a * "point or A fastening zone 6. The apparatus according to any of Claims 1 to 5, is characterized in that the clamping part (10, 16) is mounted on a pivoting casing (30) which is fixedly connected to the stop plate (5) 7. The apparatus according to any of claims 1 to 6, characterized in that a mounted closing plate with pivoting movement (27) is provided in a rest position, and is disposed obliquely. with respect to a surface that exerts pressure on the stop plate (5) 8. The apparatus according to claim 7, characterized in that the closing plate (27) can be pivoted in an activating position by moving it towards the stop plate (5) 9. The apparatus according to any of claims 1 to 8, characterized by welding tongs (34) and / or a band cutter (11) which can be pivoted below the stop plate (5), and that part of the welding tongs (34) placed in contact with the band are always covered by the stop plate '(5).