BUNDLE OF TUBULAR AND/OR ROD-SHAPED GLASS ARTICLES, METHOD FOR ITS FABRICATION AS WELL AS FOR UNPACKING SAID BUNDLE

Abstract

A method for unpacking a bundle of tubular and/or rod-shaped glass articles has the steps of holding the bundle in a locked position and pulling a thread-like element that is wrapped around the glass articles so that the thread-like element is withdrawn from the bundle. The bundle includes a longest dimension, layers (N.sub.L) of the glass articles, and the thread-like element. The longest dimension extends in a first direction. The glass articles in each layer are arranged side by side in a second direction. The layers are arranged side by side in a third direction. The first, second, and third directions are perpendicular to one another. The thread-like element is around two of the glass articles in at least one layer so that the two glass articles are spaced apart. The thread-like element has a cross section between at least 0.25 mm and at most 4.0 mm.

Claims

1. A method for unpacking a bundle of tubular and/or rod-shaped glass articles, comprising: holding the bundle in a locked position; and pulling a thread-like element that is wrapped around a plurality of the glass articles so that the thread-like element is withdrawn from the bundle.

2. The method of claim 1, wherein the step of pulling the thread-like element includes applying a pulling force or tension in an axial direction that is between 0.1 N and 4 N.

3. The method of claim 1, wherein the step of holding the bundle includes applying a supplemental normal force on the bundle that is not greater than 100 N.

4. The method of claim 1, wherein the thread-like element has a cross section between at least 0.25 mm and at most 4.0 mm, and wherein the thread-like element includes a material with a surface energy of at least 25 mN/m and at most 38 mN/m.

5. The method of claim 1, wherein the thread-like element is twisted from fibers or from strips of material and/or encompasses strings, lines, or cords and has a cross-section of at least 0.25 mm, and wherein the thread-like element is fastened to form a slipped knot or a running knot.

6. The method of claim 4, wherein the cross section is between at least 0.5 mm and at most 2.5 mm.

7. The method of claim 1, wherein the thread-like element is fastened to form a knot with an adhesive force between about 0.1 and 4.0 N.

8. The method of claim 1, wherein the thread-like element has a tensile elasticity (C.sub.S) at least 80 N to at most 700 N, and wherein the tensile elasticity (C.sub.S,) is defined by the following equation: $C_S=L.Math.\frac{\Delta F}{\Delta L}$ wherein L corresponds to an initial length of the thread-like-element, ΔL is an amount by which a length of the thread-like element changes, and ΔF is a change of tensile force in the thread-like element.

9. The method of claim 1, wherein the thread-like element has a minimum cross section (c.sub.r), wherein the thread-like element is wrapped around the glass articles at a plurality of different spaced positions (n.sub.t) along the length of the glass articles, wherein the plurality of different spaced positions and the minimum cross section are selected according to: TABLE-US-00007 C.sub.r-value N.sub.L Less than 3000 6000 . . . 12000 12000 . . . 20000 More than 20000 Less than 8 n.sub.t ≥ 2, n.sub.t ≥ 2, n.sub.t ≥ 3, n.sub.t ≥ 4, c.sub.t ≥ 0.5 mm c.sub.t ≥ 0.5 mm c.sub.t ≥ 0.9 mm c.sub.t ≥ 1.0 mm 8 to 12 n.sub.t ≥ 2, n.sub.t ≥ 2, n.sub.t ≥ 3, n.sub.t ≥ 4, c.sub.t ≥ 0.6 mm c.sub.t ≥ 0.6 mm c.sub.t ≥ 1.0 mm c.sub.t ≥ 1.1 mm More than 12 n.sub.t ≥ 3 n.sub.t ≥ 3, n.sub.t ≥ 3, n.sub.t ≥ 4, c.sub.t ≥ 0.7 mm c.sub.t ≥ 0.7 mm c.sub.t ≥ 1.1 mm c.sub.t ≥ 1.2 mm wherein the C.sub.R-value corresponds to: $C_R=\frac{l^2}{d_o^2+2t_w^2-2d_o.Math.t_w}$ wherein l corresponds to the length of the glass articles in mm, wherein d.sub.o corresponds to an outer diameter of the glass articles in mm, and wherein t.sub.w corresponds to a wall thickness of the glass articles in mm, the wall thickness of a rod-shaped article being equal to one half of the outer diameter.

10. The method of claim 9, wherein the plurality of different spaced positions (n.sub.t) are positioned so that a first distance (a) is between a half-length of the glass articles and a first spacer position, a second distance (b) is between the half-length and a second spacer position, and a third distance (c) is between the half-length and a third spacer position, wherein (a) is smaller than (b), and wherein (b) is smaller than (c), and wherein (a), (b), and (c) are chosen according to: TABLE-US-00008 n.sub.t (a) (b) (c) 2 0.25 ≤ a/L ≤ 0.29 3 −0.015 ≤ a/L ≤ 0.015 0.32 ≤ b/L ≤ 0.40 4 0.10 ≤ a/L ≤ 0.16 0.36 ≤ b/L ≤ 0.43 5 −0.025 ≤ a/L ≤ 0.025 0.18 ≤ b/L ≤ 0.24 0.38 ≤ c/L ≤ 0.44.

11. The method of claim 1, wherein the thread-like element includes a plurality of thread-like elements so that at each of the plurality of different spaced positions (n.sub.t) there is a different one of the plurality of thread-like elements.

12. The method of claim 1, wherein the thread-like element includes between at least 5 and at most 20 strands, and wherein each strand has an outer diameter of at least 0.1 mm and at most 1 mm.

12. The method of claim 1, wherein the strands are twisted so that per 1 centimetre length of the thread-like element there are at least 0.1 windings and at most 1 winding.

14. The method of claim 1, wherein the thread-like element includes a material with a surface energy of at least 25 mN/m and at most 38 mN/m.

15. The method of claim 1, wherein the thread-like element includes a plastic material selected from a group consisting of polypropylene (PP), polyethylene (PE), high-density polyethylene (HDPE), polyethylene wax, polyamide (PA), styrene-acrylonitrile resin (SAN), polyester polyethylene terephthatalate (PET), polybutylene terephthalate (PBT), polyurethane (PU), polycarbonate (PC), acrylonitrile butadiene styrene (ABS), polyether ether ketone (PEEK), and any combinations thereof.

16. The method of claim 1, wherein the thread-like element includes a material with a Young's modulus between of at least 500 MPa and of at most 1000 MPa.

17. The method of claim 1, wherein the two glass articles are spaced apart by a distance of at least 0.5 mm.

18. A method for bundling tubular and/or rod-shaped glass articles to obtain a bundle, comprising: wrapping a thread-like element around at least two of the glass articles in at least two spaced positions to form a first layer of spaced apart glass articles; wrapping another thread-like element around at least two more of the glass articles in at least two spaced positions to form a second layer of spaced apart glass articles; and stacking the first and second layers of spaced apart glass articles.

19. The method of claim 18, wherein a step of pulling the thread-like element when unpacking the bundle of tubular and/or rod-shaped glass articles includes applying a pulling force or tension in an axial direction that is between 0.1 N and 4 N.

20. The method of claim 19, wherein a step of holding the bundle when unpacking the bundle of tubular and/or rod-shaped glass articles includes applying a supplemental normal force on the bundle that is not greater than 100 N.

21. The method of claim 18, wherein the thread-like element includes between at least 5 and at most 20 strands, and wherein each strand has an outer diameter of at least 0.1 mm and at most 1 mm.

22. The method of claim 21, wherein the thread-like element has a minimum cross section (c.sub.r), wherein the thread-like element is wrapped around the glass articles at a plurality of different spaced positions (n.sub.t) along the length of the plurality of glass articles, and wherein the plurality of different spaced positions and the minimum cross section are selected according to: TABLE-US-00009 C.sub.r-value N.sub.L Less than 3000 6000 . . . 12000 12000 . . . 20000 More than 20000 Less than 8 n.sub.t ≥ 2, n.sub.t ≥ 2, n.sub.t ≥ 3, n.sub.t ≥ 4, c.sub.t ≥ 0.5 mm c.sub.t ≥ 0.5 mm c.sub.t ≥ 0.9 mm c.sub.t ≥ 1.0 mm 8 to 12 n.sub.t ≥ 2, n.sub.t ≥ 2, n.sub.t ≥ 3, n.sub.t ≥ 4, c.sub.t ≥ 0.6 mm c.sub.t ≥ 0.6 mm c.sub.t ≥ 1.0 mm c.sub.t ≥ 1.1 mm More than 12 n.sub.t ≥ 3 n.sub.t ≥ 3, n.sub.t ≥ 3, n.sub.t ≥ 4, c.sub.t ≥ 0.7 mm c.sub.t ≥ 0.7 mm c.sub.t ≥ 1.1 mm c.sub.t ≥ 1.2 mm wherein the C.sub.R-value corresponds to: $C_R=\frac{l^2}{d_o^2+2t_w^2-2d_o.Math.t_w}$ wherein l corresponds to the length of the glass articles in mm, wherein d.sub.o corresponds to an outer diameter of the glass articles in mm, and wherein t.sub.w corresponds to a wall thickness of the glass articles in mm, the wall thickness of a rod-shaped article being equal to one half of the outer diameter.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0112] FIG. 1 a schematic and not drawn to scale depiction of a tubular and/or rod-shaped glass article;

[0113] FIGS. 2a-2b are schematic depictions of two-dimensional close packings;

[0114] FIGS. 3a-3b are schematic depictions of cross sections of different glass articles;

[0115] FIGS. 4a-4b are schematic and not drawn to scale depictions of bundles of tubular and/or rod-shaped glass articles;

[0116] FIGS. 5a-5d are four schematic and not drawn to scale depictions of tubular and/or rod-shaped glass articles comprising thread-like elements at different spacer positions;

[0117] FIG. 6 is a schematic diagram as illustration for the determination of the tensile elasticity;

[0118] FIG. 7 is a schematic illustration of the measurement method for determination of circularity; and

[0119] FIGS. 8 to 12 are diagrams depicting pulling forces measured for pulling and withdrawing of thread-like elements comprised by bundles according to embodiments of the disclosure.

[0120] In the figures, like reference numerals refer to like or corresponding elements.

DETAILED DESCRIPTION

[0121] FIG. 1 is a schematic depiction of a tubular and/or rod-shaped glass article 1. The glass article has longest dimension l, likewise depicted in FIG. 1. The longest dimension—or simply length l—of the tubular and/or rod-shaped article 1 extends along a first direction of a Cartesian coordinate system, that is, here in this case, from the left to the right of the figure.

[0122] FIGS. 2a-2b are schematic depictions of a close packing of equal circles in the sense of the present disclosure. Here now, in FIG. 2a, the close packing may be understood in this case as a cross-sectional view of a bundle of rod-shaped glass articles 11, whereas, in FIG. 2b, the close packing may be understood as a cross-sectional view of a bundle of tubular glass articles 12. For the sake of visibility, only one article 11, 12 has been indicated. It is pointed out that the arrangement of circles (as in FIG. 2a) or rings (as in FIG. 2b) each consists, in this case, of four different layers of circles or rings, respectively. These layers may be understood as a layer of rod-shaped glass articles or tubular shaped glass articles, the number of layers, N.sub.L, being, in this case, 4. However, generally, without being bound be the depiction in FIGS. 2a-2b, different, particularly higher, numbers of layers are possible, of course. Further, the circles or rings are spaced apart slightly.

[0123] FIG. 3a is a cross-sectional view of rod-shaped glass article (or glass rod) 11 with outer dimension d.sub.o, the latter being equal to the diameter of the cross-section. In FIG. 3b, a cross-sectional view of tubular glass article 12 is shown. This cross-section can be defined by outer dimension d.sub.o and inner dimension d.sub.i, wherein the wall thickness t.sub.w of the tubular glass article (or glass tube) 12 corresponds to:

t.sub.w=½*(d.sub.o−d.sub.i).

[0124] It is to be noted that in the case of a rod-shaped glass article (or glass rod), the wall thickness corresponds to:

t.sub.w=½*d.sub.o,

[0125] as indicated in the FIG. 3a. That is, the wall thickness t.sub.w may also be understood as the radius of the rod-shaped glass article (or glass rod).

[0126] Now, with regard to FIGS. 4a-4b, two different embodiments of bundles 10 of tubular and/or rod-shaped glass articles 1 are shown.

[0127] FIG. 4a depicts schematically bundle 10, comprising tubular and/or rod-shaped glass articles as well as a thread-like element 2. As can be seen, the cross sections of tubular and/or rod-shaped glass articles 1 form a close packing here. Further, here, thread-like element 2 is positioned to the rear of the bundle 10 as well as near the front region. It may be noted that at both position, that is, to the rear and at the front, thread-like element 2 may be the same, that is, just one thread-like element is first wrapped around the glass articles at least partially at the rear side portions and, after that, at the front side portion. However, if may be more suitable to use, at each spacer position, a separate thread-like element 2. Further, it is to be noted that, according to the actual method used to wrap the thread-like element 2 around the tubular and/or rod-shaped glass article at least partially, more than one thread-like element may be present at a single spacer position, for example, an upper thread-like element and a lower thread-like element.

[0128] In FIG. 4b, another bundle 10 is depicted. In this case, the rod-shaped and/or tubular glass articles have been arranged so that their cross sections form a simple cubic packing. Here, the thread-like element 2 is position at three different spacer positions.

[0129] Now, in FIGS. 5a-5d, a tubular and/or rod-shaped glass article 1 is depicted. It is once again pointed out that these depictions each are merely schematic depictions and not drawn to scale. The tubular and/or rod-shaped glass article 1 in each of FIGS. 5a-5d is bent. However, the amount of bending has been exaggerated for illustrational issues.

[0130] FIG. 5a shows the case where at least one thread-like element 2 has been positioned at to spacer positions n.sub.t along length l of the article 2. These positions may be characterized by distance a, a being a first distance a between the half-length of the tubular and/or rod-shaped articles and at least one first spacer position of at the least one thread-like element.

[0131] Now, if there are, as depicted in FIG. 5b, there are three spacer position n.sub.t, these three positions can be characterized by distances a and b, a being a first distance a between the half-length of the tubular and/or rod-shaped articles and at least one first spacer position of at the least one thread-like element and b being a second distance b between the half-length of the tubular and/or rod-shaped articles and at least one second spacer position of the at least one thread-like element; a being smaller than b.

[0132] Further, in the case shown in FIG. 5c, four spacer positions are distributed along length l. These four position can likewise be characterized by distances a and b, a being a first distance a between the half-length of the tubular and/or rod-shaped articles and at least one first spacer position of at the least one thread-like element and b being a second distance b between the half-length of the tubular and/or rod-shaped articles and at least one second spacer position of the at least one thread-like element; a being smaller than b.

[0133] Furthermore, as shown in FIG. 5d, if five spacer positions are distributed, then these can be characterized by distances a, b, and c, a being a first distance a between the half-length of the tubular and/or rod-shaped articles and at least one first spacer position of at the least one thread-like element, b being a second distance b between the half-length of the tubular and/or rod-shaped articles and at least one second spacer position of the at least one thread-like element, and c a third distance c between the half-length of the tubular and/or rod-shaped articles and at least one third spacer position of at the least one thread-like element, with a being smaller than b and b being smaller than c. Distances a, b and c are chosen according to the following table:

TABLE-US-00005 n.sub.t a b c 2 0.25 ≤ a/L ≤ 0.29 3 −0.015 ≤ a/L≤ 0.015 0.32 ≤ b/L ≤ 0.40 4 0.10 ≤ a/L ≤ 0.16 0.36 ≤ b/L ≤ 0.43 5 −0.025 ≤ a/L ≤ 0.025 0.18 ≤ b/L ≤ 0.24 0.38 ≤ c/L ≤ 0.44

[0134] It may be preferred that the spacer positions are arranged symmetrically, that is, for uneven numbers of spaced positions, when a is 0 or nearly 0.

[0135] For the sake of illustration, values of maximum distances between outermost spacer positions as well as for a, b and c (where applicable) for a length l of 1.5 m are shown in the following table. Here, d.sub.s denotes the maximum distance between spacer positions, that is, the distance between the outermost thread-like elements, and d.sub.a, the average distance between adjacent spacer positions.

TABLE-US-00006 n.sub.t a b c d.sub.s d.sub.a 2 37.5 cm ≤ a ≤ 43.5 cm 75 cm ≤ d.sub.s ≤ 87 cm 75 cm ≤ d.sub.a ≤ 87 cm 3 −2.5 cm ≤ a ≤ 3.75 cm 48 cm ≤ b ≤ 60 cm 96 cm ≤ 120 cm 48 cm ≤ b ≤ 60 cm 4 15 cm ≤ a ≤ 24 cm 54 cm ≤ b ≤ 64.5 cm 108 cm ≤ d.sub.s ≤ 129 cm 36 cm ≤ d.sub.a ≤ 43 cm 5 −2.5 cm ≤ a ≤ 3.75 cm 27 cm ≤ b ≤ 36 cm 57 cm ≤ c ≤ 66 cm 114 cm ≤ d.sub.s ≤ 132 cm 28.5 cm < d.sub.a ≤ 33 cm

[0136] A negative a-value means that the distance deviating from the half length of the glass article to the “left” side (that is, in direction of the “left end”) of the glass article as depicted in FIGS. 5a-5d.

[0137] The average distance d.sub.a between adjacent spacers may be about 28.5 cm or else about 33 cm or else about 36 cm or else about 43 cm or else about 48 cm or else about 75 cm or else about 75 cm or else about 87 cm, the average distance may vary depending upon the number of spacers arranged along the length of the glass articles. Further, the average distance will be less for a greater number of spacers.

[0138] Taking into account the maximum distances between the outermost spacer positions, d.sub.s, the average distance d.sub.a between different spacers positions can be determined. Of course, the actual distance between spacer positions may differ slightly from this average value, especially taking into account the a-value for deviation from a perfect, most preferred symmetrical arrangement of spacer positions, that is, for a value of a≠0 in cases where there is an uneven number of spacer positions.

[0139] In FIG. 6, a schematic diagram for determination of the tensile elasticity is shown.

[0140] It is reminded that C.sub.S, the tensile elasticity, is given according to the following equation:

[00003]$C_S=L.Math.\frac{\Delta F}{\Delta L},$

[0141] wherein L corresponds to the initial length of the thread-like-element (plotted along the y-axis), ΔL is the amount by which the length of the thread-like element changes, and ΔF is the change of the tensile force in the thread-like element, as determined in usual load-strain-curves as shown in the schematic diagram of FIG. 6, that is, by the ratio of the strain (or relative elongation of the respective thread-like element ΔL/L) and the change of the tensile strength, ΔF, in the respective thread-like element.

[0142] FIG. 7 shows schematically the determination of the circularity error, here denoted as ci. The circularity error ci, in this case, is a measure for the deviation of a given shape from the ideal circular shape, Here, a circumferential line of a cross section has to lie in a plane defined by two concentrical circles (that are depicted in FIG. 7 with dotted lines) with a specific, predefined distance from each other. The actual value of the circularity error ci is one half of the maximum difference the outer diameters in the respective plane. In actual practice, instead of the circularity error, the ovality may be given, the ovality being the difference of the maximum outer cross section and the minimum outer cross section in a direction perpendicular to the length l of a rod-shaped or tubular glass article. The ovality is two times the value of the circularity error.

[0143] FIGS. 8 to 12 show diagrams of pulling forces obtained for thread-like elements 2 in bundles 10 according to embodiments of the present disclosure. In all bundles, thread-like elements arranged at a spacer position had been wrapped around the glass articles at least partially in order to space the glass articles apart. Further, the thread-like elements had been wrapped around the glass articles at least partially, forming several knots. These knots were, for each bundle, formed as releasable knots, that is, knots that could easily be untied by pulling one free end of one thread-like element forming the bundle. In each of FIG. 8 to 12, the pulling force (or tension), given in N, has been plotted over the position of the puller used for withdrawal of the at least one thread-like element. Puller position is given in arbitrary units. In each of the diagrams, measurement was conducted for four different layers of glass articles. Furthermore, in all cases, bundles were arranged in a horizontal position. The number of knots, in each of the examples used for measurement, corresponded to the number of glass articles in a layer. Maximum values correspond to untying of the knot and, thus, to the maximum adhesive force of the knot. Therefore, the maximum measured value corresponds to the minimum value of tension needed for untying of a knot.

[0144] In between the maxima, measured tension values correspond to those stages of unpacking wherein simple withdrawal of the thread-like element takes place. In consequence, as no adhesive force of a knot needs to be overcome, much less tension is needed in these stages.

[0145] As can be seen in the five diagrams depicting measured tension values needed for withdrawal and untying of knots in bundles of glass articles with different cross sections, minimum pulling forces required depend upon the cross section of the bundled glass articles.

[0146] FIG. 8 is a diagram depicting pulling forces measured in bundles of tubular and/or rod-shaped glass articles with cross sections of 10.95 mm, indicated as data sets 8-1, 8-2, 8-3 and 8-4. The statistical nature of minimum pulling force or maximum adhesive force of a knot can clearly be seen, as peak values obtained during measurement may range from a value of slightly more than 3 N (data set 8-1, first peak value) to less than 1.5 N or even less (data set 8-3), with an average value of about 2.2 N.

[0147] FIG. 9 depicts pulling force over puller position for bundles of tubular and/or rod-shaped glass articles with a cross section of about 16 mm, indicated as data sets 9-1, 9-2, 9-3 and 9-4. Minimum pulling forces ranged from 1.1 N or even less (data set 9-3) to a value of 2.13 N (data set 9.1), with an average of about 1.6 N.

[0148] In FIG. 10, for data sets 10-1, 10-2, 10-3 and 10-4, obtained for a cross section of the bundled tubular and/or rod-shaped glass articles of 28 mm, the maximum measured pulling force value (corresponding to the minimum pulling force or, in the alternative, to the maximum adhesive force of the knot) was about 2.1 N (set 10-2), whereas very low values were obtained in set 10-3, corresponding to about 0.5 N. The average “minimum pulling force” amounted to about 1.2 N.

[0149] FIG. 11, depicting data sets 11-1, 11-2, 11-3 and 11-4, for cross sections of glass articles of about 8.65 mm, shows a peak value of the pulling force of about 2.4 N (data set 11-2), whereas for some knots, a pulling force as low as 1.4 N (11-3) or even less proved sufficient for releasing tied knots. Average “minimum pulling force” amounted to about 2 N.

[0150] Finally, FIG. 12 depicts data sets 12-1, 12-2, 12-3 and 12-4, for cross sections of bundled glass articles of about 42 mm. A peak value of 1.3 N was obtained for set 12-2, whereas pulling forces for releasing knots could also be as low as 0.7 N (set 12-1) or lesser still, for example 0.4 N (set 12-2). Average was about 0.9 N.

[0151] As can be seen, the force required for untying a knot differs and in general is lower the larger the cross section of the bundled articles. However, for smaller cross sections, that is, for cross sections less than about 12 or 11 mm, there seems to be a plateau or “pedestal” section, with minimum pulling forces varying about an average value of about 1.9-2.3 N.

REFERENCE NUMERALS

[0152] 1 tubular and/or rod-shaped glass article [0153] 11 rod-shaped glass article [0154] 12 tubular glass article [0155] 10 bundle [0156] 2 thread-like element [0157] 8-1, 8-2, 8-3, 8-4 data sets for pulling forces for glass article cross sections of 10.95 mm [0158] 9-1, 9-2, 9-3, 9-4 data sets for pulling forces for glass article cross sections of 16 mm [0159] 10-1,10-2, 10-3, 10-4 data sets for pulling forces for glass article cross sections of 28 mm [0160] 11-1, 11-2, 11-3, 11-4 data sets for pulling forces for glass article cross sections of 8.65 mm [0161] 12-1, 12-2, 12-3, 12-4 data sets for pulling forces for glass article cross sections of 42 mm [0162] a, b, c distances [0163] l length of the glass article [0164] d.sub.o outer dimension of cross section, diameter of a rod, outer diameter of a tube [0165] d.sub.i inner dimension of tubular cross section [0166] t.sub.w wall thickness [0167] ci circularity error