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(11) | EP 4 570 722 A1 |
| (12) | EUROPEAN PATENT APPLICATION |
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| (54) | A SUPPORT PLUG FOR A TUBULAR ROLLER SLEEVE |
| (57) A disk-shaped support plug (100) for a tubular roller sleeve comprises a first surface
(101), a second surface on an opposite side of the support plug with respect to the
first surface, a through hole (103) on the center of the support plug, and an outer
rim surface (105) for being against an inner surface of the tubular roller sleeve.
The outer rim surface (105) and a surface (104) of the through hole connect the first
surface to the second surface. The first surface has recessions (106, 107) such that
stiffener ridges (108, 109) are formed between the recessions. The stiffener ridges
extend between different sectors of an outer rim area of the first surface so that
the stiffener ridges bypass the through hole. Thus, the stiffener ridges conduct mechanical
tensions to bypass a rim area of the through hole which is typically a fracture-prone
area.
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Technical field
[0001] The disclosure relates to a support plug for a tubular roller sleeve, especially for a tubular roller sleeve made of cardboard.
Background
[0002] In many cases, paper or another sheet-like product is rolled around a tubular roller sleeve which can be made of e.g. cardboard. The tubular roller sleeve can be however unsuitable for being directly in a mechanical contact with a shaft of a roller machine or another device for handling the tubular roller sleeve, but there is a need for support plugs such that an outer rim surface of each support plug is against an inner surface of the tubular roller sleeve and each support plug has a through hole in the center of the support plug. The through hole is suitable for the shaft of the roller machine or the other device for handling the tubular roller sleeve. A support plug of the kind mentioned above must fulfill given mechanical durability requirements. For example, a support plug must be sufficiently strong against mechanical compression in a radial direction of the support plug so that the support plug does not buckle and/or break under radial compression.
[0003] Typically, support plugs of the kind mentioned above are made of plywood whose thickness ranges from 20 mm to 40 mm. An advantage of a support plug made of plywood is the ability to withstand mechanical compression in radial directions because plywood consists of veneer layers with crossing grain directions. On the other hand, an inconvenience related to support plugs made of plywood is their weight. Furthermore, plywood is virginal material, and this inherently increases costs of the support plugs made of plywood.
[0004] To reduce material costs and to reduce use of virginal materials, there is nowadays a desire to manufacture many elements such as support plugs of the kind mentioned above from recycled materials, such as recycled plastic, and/or from surplus materials, such as sawdust and wood chips, remaining during manufacture of other products.
Summary
[0005] The following presents a simplified summary to provide a basic understanding of some aspects of various invention embodiments. The summary is not an extensive overview of the invention. It is neither intended to identify key or critical elements of the invention nor to delineate the scope of the invention. The following summary merely presents some concepts of the invention in a simplified form as a prelude to a more detailed description of exemplifying embodiments of the invention.
[0006] In this document, the word "geometric" when used as a prefix means a geometric concept that is not necessarily a part of any physical object. The geometric concept can be for example a geometric point, a straight or curved geometric line, a planar or non-planar geometric surface, a geometric space, or any other geometric entity that is zero, one, two, or three dimensional.
[0007] In accordance with the invention, there is provided a support plug for a tubular roller sleeve, especially for a tubular roller sleeve made of cardboard. A support plug according to the invention is disk-shaped and comprises:
- a first surface,
- a second surface on an opposite side of the support plug with respect to the first surface,
- a through hole in the center of the support plug, a surface of the through hole connecting the first surface to the second surface, and
- an outer rim surface connecting the first surface to the second surface and suitable for being against an inner surface of the tubular roller sleeve.
[0008] The above-mentioned first surface has recessions such that stiffener ridges are formed between the recessions. The stiffener ridges extend between different sectors of an outer rim area of the first surface so that the stiffener ridges bypass the through hole. Thus, the stiffener ridges conduct mechanical tensions to bypass a rim area of the through hole which is typically a fracture-prone area. Furthermore, as the stiffener ridges extend between different sectors of the outer rim area, the ridges provide mechanical strength against buckling under radial compression.
[0009] A support plug according to the invention can be made of for example recycled plastic or of composite material comprising recycled plastic and wood fibers.
[0011] Various exemplifying and non-limiting embodiments both as to constructions and to methods of operation, together with additional objects and advantages thereof, will be best understood from the following description of specific exemplifying and non-limiting embodiments when read in conjunction with the accompanying drawings.
[0012] The verbs "to comprise" and "to include" are used in this document as open limitations that neither exclude nor require the existence of unrecited features.
[0013] The features recited in dependent claims are mutually freely combinable unless otherwise explicitly stated.
[0014] Furthermore, it is to be understood that the use of "a" or "an", i.e. a singular form, throughout this document does not exclude a plurality.
Brief description of figures
[0015] Exemplifying and non-limiting embodiments and their advantages are explained in greater detail below in the sense of examples and with reference to the accompanying drawings, in which:
figures 1a and 1b illustrate a support plug according to an exemplifying and non-limiting embodiment and suitable for a tubular roller sleeve.
Description of exemplifying and non-limiting embodiments
[0016] The specific examples provided in the description below should not be construed as limiting the scope and/or the applicability of the accompanied claims. Lists and groups of examples provided in the description are not exhaustive unless otherwise explicitly stated.
[0017] Figure 1a shows a perspective view of a support plug 100 according to an exemplifying and non-limiting embodiment and suitable for a tubular roller sleeve. Figure 1b shows a section view of the support plug 100. The section surface is denoted with a diagonal hatching in figure 1b. The viewing directions related to figures 1a and 1b are illustrated with a coordinate system 199. The support plug 100 is disk-shaped, and the support plug 100 comprises a first surface 101, a second surface 102 on an opposite side of the support plug 100 with respect to the first surface 101, a through hole 103 in the center of the support plug, and an outer rim surface 105 suitable for being against an inner surface of the tubular roller sleeve. The outer rim surface 105 and a surface 104 of the through hole 103 connect the first surface 101 to the second surface 102.The first surface 101 has recessions such that stiffener ridges are formed between the recessions. Two of the recessions are denoted with references 106 and 107 in figures 1a and 1b. Two of the stiffener ridges are denoted with references 108 and 109 in figure 1a. Three of the stiffener ridges are illustrated with dashed lines in figure 1a. The stiffener ridges extend between different sectors of an outer rim area of the first surface 101 so that the stiffener ridges bypass the through hole 103. Thus, the stiffener ridges conduct mechanical tensions to bypass a rim area of the through hole 103 which is typically a fracture-prone area. Furthermore, as the stiffener ridges extend between different sectors of the outer rim area, the ridges provide mechanical strength against buckling under radial compression by forces F and -F shown in figure 1a.
[0018] In a support plug according to an exemplifying and non-limiting embodiment, the stiffener ridges cross each other as illustrated in figure 1a. The stiffener ridges crossing each other form triangles which are inherently stiff mechanical structures.
[0019] In a support plug according to an exemplifying and non-limiting embodiment, the first surface 101 has an annular recession 110 surrounding the through hole 103. In a support plug according to an exemplifying and non-limiting embodiment, the second surface has an annular ridge 111 surrounding the through hole 103. In a support plug according to an exemplifying and non-limiting embodiment, the first surface 101 has an annular recession 112 on the outer rim area of the first surface. In a support plug according to an exemplifying and non-limiting embodiment, the second surface 102 has an annular ridge 113 on an outer rim area of the second surface. In a support plug according to an exemplifying and non-limiting embodiment, a part 115 of the second surface 102 extending from an outer rim area of the second surface 102 to an inner rim area of the second surface 102 surrounding the through hole 103 is conical. A cone angle θ of the conical surface is at least 170 degrees, and the cone angle θ opens in a direction away from the first surface 101, i.e. in the negative z-direction of the coordinate system 199.
[0020] By design of the above-mentioned annular recessions 110 and 112, the annular ridges 111 and 114, and the conicity of the second surface 102 it is possible to adjust tension distribution within the material of the support plug 100 in the axial direction of the support plug 100, i.e. in the z-direction of the coordinate system 199. Thus, the above-mentioned annular recessions, the annular ridges, and the conicity of the second surface 102 can be optimized to maximize mechanical strength of the support plug 100 against buckling with respect to amount of the material of the support plug 100. The annular recessions, the annular ridges, and the conicity of the second surface 102 can be optimized with e.g. prototypes and tests and/or with strength-technical simulations.
[0021] In a support plug according to an exemplifying and non-limiting embodiment, the depths of the recessions of the first surface 101 are such that material thickness between bottoms of the recessions of the first surface 101 and the second surface 102 is substantially constant. In figure 1b, the above-mentioned material thickness is denoted by D. The constant material thickness facilitates avoiding local tension maxima.
[0022] In a support plug according to an exemplifying and non-limiting embodiment, a part of the outer rim surface 105 connected to the second surface 102 has a bevel 114. The bevel 114 makes it easier to install the support plug 100 in a tubular roller sleeve.
[0023] In a support plug according to an exemplifying and non-limiting embodiment, the outer rim surface 105 comprises lumps on the periphery of the support plug 100 to improve a grip between the support plug 100 and an inner surface of a tubular roller sleeve. In figure 1a, one of the lumps is denoted with reference 116.
[0024] A support plug according to an exemplifying and non-limiting embodiment is made of plastic that is advantageously recycled plastic.
[0025] A support plug according to an exemplifying and non-limiting embodiment is made of composite material comprising wood fibers and plastic. The wood fibers and/or the plastic is/are advantageously recycled material.
[0026] A support plug according to an exemplifying and non-limiting embodiment is manufactured with compression molding or some other suitable manufacturing method.
[0027] The specific examples provided in the description given above should not be construed as limiting the applicability and/or interpretation of the appended claims. It is to be noted that lists and groups of examples given in this document are non-exhaustive lists and groups unless otherwise explicitly stated.
1. A support plug (100) for a tubular roller sleeve, the support plug being disk-shaped
and comprising:
- a first surface (101),
- a second surface (102) on an opposite side of the support plug with respect to the first surface,
- a through hole (103) in a center of the support plug, a surface (104) of the through hole connecting the first surface to the second surface, and
- an outer rim surface (105) connecting the first surface to the second surface and suitable for being against an inner surface of the tubular roller sleeve,
wherein the first surface has recessions (106, 107) such that stiffener ridges (108, 109) are formed between the recessions, characterized in that the stiffener ridges extend between different sectors of an outer rim area of the first surface so that the stiffener ridges bypass the through hole.2. A support plug according to claim 1, wherein the stiffener ridges (108, 109) cross
each other.
3. A support plug according to claim 1 or 2, wherein the first surface has an annular
recession (110) surrounding the through hole.
4. A support plug according to any one of claims 1-3, wherein the second surface has
an annular ridge (111) surrounding the through hole.
5. A support plug according to any one of claims 1-4, wherein the first surface has an
annular recession (112) on the outer rim area of the first surface.
6. A support plug according to any one of claims 1-5, wherein the second surface has
an annular ridge (113) on an outer rim area of the second surface.
7. A support plug according to any one of claims 1-6, wherein a part of the outer rim
surface (105) connected to the second surface has a bevel (114).
8. A support plug according to any one of claims 1-6, wherein a part (115) of the second
surface extending from an outer rim area of the second surface to an inner rim area
of the second surface surrounding the through hole (103) is conical with a cone angle
(θ) at least 170 degrees and opening in a direction (-z) away from the first surface.
9. A support plug according to any one of claims 1-8, wherein depths of the recessions
(106, 107) of the first surface are such that material thickness between bottoms of
the recessions of the first surface and the second surface is constant (D).
10. A support plug according to any one of claims 1-9, wherein the outer rim surface (105)
comprises lumps (116) to improve a grip between the support plug and the inner surface
of the tubular roller sleeve.
11. A support plug according to any one of claims 1-10, wherein support plug is made of
plastic.
12. A support plug according to any one of claims 1-10, wherein support plug is made of
composite material comprising wood fibers and plastic.