BE1030024B1 - A METHOD FOR MANUFACTURING A PRODUCT WITH AN OUTER SURFACE OF AT LEAST TWO ELEMENTS - Google Patents

Abstract

A method of manufacturing a product having an outer surface of at least two elements is provided, the method comprising the steps of: providing the two or more elements to provide the surface of the product; • assembling the two or more elements into an intermediate product, whereby seams between two or more elements are visible on the surface of the intermediate product; • vacuum coating the intermediate product until at least the seams are invisible.

Description

1 BE2021/5987

A METHOD OF MANUFACTURING A PRODUCT WITH

AN OUTER SURFACE OF AT LEAST TWO ELEMENTS

Technical area

[01] The invention relates to methods of manufacturing a product with an outer surface of at least two elements. In particular, the invention relates to methods of manufacturing an earplug, which earplug comprises a part which is a product with an outer surface of at least two elements.

State of the art

[02] Products with an outer surface of at least two elements are known. These are often polymeric products, the outside of which is provided by parts of the product that fit together. Seams are visible on the outside. The presence of seams is often regarded as a sign of inferior or lower quality compared to comparable products that are made from one solid piece. However, such massive one-piece products are more difficult or sometimes impossible to manufacture.

Summary of the invention

[03] It is an object of the invention to provide methods for manufacturing a product with an outer surface of at least two elements, which products give the impression of being one solid whole.

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[04] According to a first aspect of the invention, there is provided a method of manufacturing a product having an outer surface of at least two elements, the method comprising the steps of: e providing the two or more elements which are in the surface of the product provides; e assembling the two or more elements into an intermediate product, wherein seams between two or more elements are visible on the surface of the intermediate product; e coating the intermediate product until at least the seams are invisible, whereby one or more coating layers are applied, at least one coating layer is applied by vacuum coating.

[05] One, several or all coating layers can be applied by vacuum coating.

[06] The method has the advantage that the seams between two or more elements on the outside of the product, hereinafter also referred to as a multi-element product, are hidden, thus giving the product the appearance of a solid and robust one-piece product. The seams are also perfectly sealed. By sealing and hiding the seams, the inside of the product is also shielded from environmental elements, such as light, humidity and noise, that prevail outside the product. The method further has the advantage that the surface of the product is smooth and evenly coated, which can reduce or prevent the adhesion of dirt.

[07] The use of a vacuum-coated layer as at least one layer of the coating has the further advantage that even very small, minute gaps at the seams will be sealed.

[08] In some embodiments, the at least one vacuum coated coating layer may be a metal coating layer.

[09] As an example, the vacuum coated coating layer may be made of ferrous or non-ferrous metals or alloys, which metals or alloys

3 BE2021/5987 can be deposited on the surface of the intermediate product via vacuum coating. Examples of metals and alloys used are steel and stainless steel, chromium, titanium (or titanium), copper, silver, gold, aluminum, zirconium, bronze, or nitrides such as titanium nitride, which gives a golden appearance, chromium nitride which gives a silver appearance, zirconium nitride which gives a rose gold appearance, titanium aluminum nitride, titanium boron nitride, titanium oxynitride, titanium carbonitride, zirconium oxynitride, aluminum nitride, etc.

A thin but even coating can thus be provided, while the thickness of the coating will typically be slightly thicker at the seams. However, the coating at the level of these seams will be even and smooth, so that the surface will not show the traces of an underlying seam. The product takes on a metallic appearance and can create the illusion of a robust one-piece metal object. A total coating thickness of minimum 0.015mm is preferably applied. A total coating thickness between 0.018mm and 0.050mm can be applied, for example a coating thickness between 0.020mm and 0.036mm. For example, a coating consisting of three layers may include a primer layer with a thickness in the range of 11 to 20 um (for example, between 12 and 18 um), a vacuum coated layer with a thickness of between 3 and 10 um (for example, between 4 and 8 um) and a finishing layer with a thickness between 4 and 12 um (for example between 5 and 10 um).

[10] This metal coating will protect the underlying material, often polymer, against influences such as UV light, oxygen, moisture, and the like, so that the aging of the underlying material is delayed or prevented.

[11] In some embodiments, coating the intermediate product may include applying a primer coating layer, applying the vacuum coated coating layer, and applying a finishing layer.

[12] In some embodiments, the two or more elements may be polymeric elements.

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[13] All elements can be made of the same polymer, or they can be made of different polymer.

[14] In some embodiments, the polymeric elements may comprise thermoplastic polymer.

[15] The polymeric elements may be made of thermoplastic polymer. Possible polymers are, for example, polyvinyl chloride (PVC), polyethylene (PE), polypropylene (PP) or acrylonitrile-butadiene-styrene (ABS).

[16] In some embodiments, the polymeric elements

Acrylonitrile Butadiene Styrene (ABS).

[17] In some embodiments, at least one of the two or more elements, and preferably all elements, may be injection molded.

[18] According to alternatives, one or more elements are formed by, for example, injection molding, casting, milling, 3D printing or compression molding.

[19] The two or more elements are assembled or assembled into a multi-element intermediate product of these two or more elements. The multiple elements are fastened together. This can be done, for example, by providing a click connection between one or more pairs of adjacent elements. The fastening may also include gluing together one or more pairs of adjacent elements, optionally in addition to providing a snap connection. The fastening may also include welding together one or more pairs of adjacent elements, optionally in addition to providing a snap connection. This welding may include thermal or ultrasonic welding. This ultrasonic welding has the advantage that no additional seams or grooves are formed, but can be done very precisely.

[20] In some embodiments, one or more pairs of adjacent elements may be welded together by ultrasonic welding.

[21] In some embodiments, the product may comprise a hollow open torus, with a tubular body attached to the torus whose outer wall connects to the torus. The internal cavity of the tubular body is separated from the cavity of the hollow open torus, for example, by the wall of the torus 5 passing through and the internal cavity or channel of the tubular body close to the contact side between the tubular body and the torus. Radial reinforcing ribs can be provided in the cavity of the hollow open torus.

[22] A torus is a three-dimensional body of revolution, which is created by revolving a circle about a line or axis that is in the plane of the circle. Open tori are also called donut shapes. The hollow open torus has a cavity or channel internally which surrounds or encircles the axis. In alternative embodiments, the product may comprise a torus-like hollow body of revolution, obtained by revolving a closed 2D figure around an axis, for example an ellipse or a polygon, optionally with rounded corners, for example a triangle, quadrilateral, pentagon or hexagon. In open torus-like bodies of revolution, the axis does not intersect the revolved figure.

[23] According to some embodiments, the axis of the tubular body and the axis of the torus can form an angle (α) between 0° and 60°

[24] Preferably, the axis of the tubular body and the axis of the torus form an angle (α) between 0° and 45°. The angle between the two axes is defined as the smallest angle measurable between these two axes when the axes are perpendicularly projected onto a plane parallel to both axes.

The axis of the tubular body is the axis of the straight part of the tube, and does not take into account the direction of the axis in the connection part to the torus.

An angle of 0° gives an axis of the tubular body and the axis of the torus that are parallel. An angle of 90° is formed when the axis of the tubular body extends radially with respect to the torus.

[25] Since the center plane of the torus is perpendicular to the axis of the torus, the angle between the center plane of the torus and the axis of the tubular body is preferably between 90° and 150°, for example 100°. This corner will be

6 BE2021/5987 measured in the plane defined by the axis of the cylindrical body, which plane is perpendicular to the center plane of the torus.

[26] The torus has a minimum or inner diameter preferably between 5 and 15mm, and a maximum or outer diameter preferably between 10 and 20mm.

[27] The tubular body need not necessarily be straight along its entire length, but may be partially curved. The outer diameter of the tubular body is preferably identical to the diameter of the circle whose revolution forms the torus. Alternatively, the outer diameter of the tubular body may be different from the diameter of the circle whose revolution forms the torus.

[28] In some embodiments, the product may include an outer surface consisting of two elements.

[29] In some embodiments, the first element may comprise the tubular body and a first of two sections of the hollow open torus, the two sections being formed by cutting the hollow open torus with an imaginary cutting plane perpendicular to the axis of the hollow open torus.

The second element may comprise the second of two sections of the hollow open torus.

[30] In some embodiments, the two sections may each form half of the torus.

[31] The imaginary section plane thus intersects the torus at the level of the circle formed by the positions of the center of the revolving circle, which is at the level of the center plane of the torus. This means that the imaginary cutting plane is coplanar with this center circle.

[32] According to an alternative embodiment, the product comprises a hollow open torus and a tubular part or body. The tubular body has

7 BE2021/5987 an axis, which axis forms an angle α with the axis of the hollow open torus and which axis intersects with the center circle of the hollow open torus.

[33] The product consists of two elements. The product is cut by two imaginary cutting planes. A first cutting plane cuts the torus perpendicular to the axis of the torus into two equal halves. The one imaginary cutting plane thus cuts the ring into two equal halves above and below the center circle of the ring. The second imaginary plane cuts the tubular body into two halves, and this cutting plane is coplanar with the axis of the tubular body. The two imaginary cutting planes are oriented relative to each other in such a way that the two cutting planes themselves intersect along a line that coincides with the tangent to the center circle of the hollow ring at the height of the intersection of this center circle with the axis of the tubular body. This line is perpendicular to the axis of the boot-shaped body.

[34] A first element is the part of the product which lies above the two imaginary intersections, the second element is the part of the product which lies below these two imaginary intersections. These two elements, one forming the upper part of the product, the other the lower part, are preferably made of ABS and can be glued or welded together, for example with ultrasonic welding.

[35] In general, the elements are preferably polymeric, more preferably ABS elements, which are welded together with an ultrasonic weld.

[36] The weld can consist of two circles, one circle on the outside of the hollow open torus, and one circle on the inside of the hollow open torus, at the level of the center plane of the torus.

[37] The wall thickness of the elements is preferably between 0.6mm and 2mm.

[38] In some embodiments, the hollow open torus may have an opening on the inside of the hollow open torus at where the tubular body attaches or couples to the hollow open torus.

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[39] In some embodiments, the product may be part of an earplug.

[40] According to some embodiments, the product may provide the outer portion of the earplug.

[41] According to a second aspect of the invention, there is provided a method of manufacturing an earplug, the method comprising the steps of forming a product by a method according to the first aspect of the invention, the product comprising the outer ear portion of the ear plug includes; e applying a plug to the outer ear part of the earplug.

[42] The plug is the inner ear part, also known as the earmold. The earplug may also include a filter. Preferably, this filter is attached to the outer ear part, for example glued or attached with double-sided tape, with, for example, modified acrylic as adhesive, at the level of the transition between the outer ear and the inner ear part. The filter is preferably suitable for acoustic purposes. The filter may consist of one, two or more layers, and each layer may be suitable for acoustic applications. The layer or layers can for instance be meshes, or foams, membranes, etc. The layer or layers can be glued together. One or more layers may be pressed into the cavity of the outer ear portion.

[43] In the embodiments where the outer ear portion comprises a hollow open torus and a tubular body, or tubular portion, the filter may be glued to the end of the tubular body.

[44] The independent and dependent claims specify specific and preferred features of the embodiments of the invention.

Features of the dependent claims may be combined with features of the independent and dependent claims, or with features described above and/or below, in any suitable manner as would be apparent to a person skilled in the art.

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[45] The above and other features, properties and advantages of the present invention will be elucidated with the aid of the following examples of embodiments, possibly in conjunction with the drawings.

[46] The description of these exemplary embodiments is provided for the purpose of illustration, without the intention of limiting the scope of the invention.

Reference numerals in the following description refer to the drawings. Same reference numerals in possibly different figures refer to identical or similar elements.

Brief description of the figures

[47] In order to better demonstrate the features of the invention, some preferred embodiments are described below by way of example without any limiting character, with reference to the accompanying drawings. e Figure 1 is a schematic representation of an embodiment of a method according to the invention. e Figure 2 is a schematic representation of two elements which together form a product with an outer surface of at least two elements. Figures 3 and 4 show a schematic representation of a first product formed according to the method of Figure 1. Figure 3 is a plan view, whereas Figure 4 is a side view of the product. e Figure 5 shows a cross-section of a first product formed according to the method of Figure 1.

[48] Like reference numerals refer to similar or identical features or objects in the various figures.

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Description of Examples of Embodiments

[49] The present invention is described below using specific embodiments.

[50] It should be noted that the term "comprising", for example as used in the claims, should not be interpreted in a limiting sense, limiting to the following elements, features and/or steps. The term "comprising" does not exclude the presence of other elements, features or steps.

[51] Thus, the scope of an expression "an object comprising the elements A and B" is not limited to an object containing only the elements

contains A and B. The scope of an expression "a method comprising steps A and B" is not limited to a method containing only steps A and

B contains.

[52] In the light of the present invention, these terms mean only that the relevant elements and steps for the invention are elements and steps A and B, respectively.

[53] In the specification that follows, reference is made to "an embodiment" or "the embodiment." Such reference means that a specific element or feature described with reference to this embodiment is included in at least this one Embodiment.

[54] However, the occurrence of the terms "in one embodiment" or "in the embodiment" at different places in this specification does not necessarily refer to the same embodiment, although it may refer to the same embodiment.

[55] Furthermore, the properties or features may be combined in any suitable manner in one or more embodiments, as would be apparent to those skilled in the art.

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[56] An example of a method 1 for manufacturing polymeric products according to the invention is schematically represented in Figure 1. In step 10, at least two, and in this example two elements 110 and 120 that provide the surface of the product, are formed by injection molding. The polymer used is ABS. Two such elements 110 and 120 are depicted in Figure 2.

[57] The elements to be assembled are possibly slightly touched up in step 20, for example to remove burrs or to remove small irregularities.

[58] In step 30, elements 110 and 120 are brought together, assembled and bonded together by ultrasonic welding. An intermediate product is formed where the seams between the elements are visible. In step 40, the intermediate product is vacuum coated with a metal coating, for example a coating of titanium nitride, chromium nitride or zirconium nitride. A coating consisting of three layers was provided, comprising the primer layer with thickness in the range of 12 and 18 µm, a vacuum coated layer with thickness between 4 and 8 µm and a finishing layer with thickness between 5 and 10 µm. Due to this total coating, the seams 250 under the coating are hidden and sealed, and traces of seams are no longer visible on the outside of the coated product. The product now looks like a solid piece of metal.

[59] The first element 110 comprises the tubular body 220 and a first 111 of two sections of the hollow open torus 210, which two sections 111 and 112 are formed by cutting the hollow open torus 210 with an imaginary cutting plane perpendicular to the axis 211 of the hollow open torus. The second element 120 comprises the second 112 of two sections of the hollow open torus.

The two sections thus each comprise half of the torus shapes. The imaginary plane of intersection thus intersects the torus at the level of the circle formed by the positions of the centers of the revolving circle.

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[60] The manufactured product may be part of an earplug. The manufacture of this earplug may further include providing a plug, for example a silicone polymer conical plug, which fits onto the end of the tubular portion of the first element. This plug is plugged onto this end of the tubular part of the first element, possibly after an acoustic filter has been applied, for example glued, to the end of the tubular part.

[61] A first product 100 that forms part of an earplug, and which part is manufactured according to method 1 described above, is shown in Figure 3 and Figure 4.

[62] The product 100 comprises an open torus 210 with a tubular body 220 attached thereto which has an apex 221 that connects to the torus. The opposite side 222 includes coupling ribs 223 for coupling to another product. The open torus is formed by revolving a circle of diameter 219 about a central axis 211, the center of the circle itself describing a circle 218 about axis 211. A radial section of the torus 210 is shown in Figure 5. The torus 210 is hollow inside. A channel-shaped cavity 240 is provided, which has, for example, two straight walls 241 which are connected to each other by two curved walls 242. Other shapes for this cavity are possible. The two elements 110 and 120, each providing a part of the torus 210, touch each other along an abutting surface 243. The abutting surface has such a shape that the outer seam 250 does not extend radially towards the channel-shaped cavity 240, but that the inner part of the seam 250 forms a zigzag line in the radial direction. Given the circular outer surface of the torus on the one hand and the channel-shaped shape of the cavity on the other hand, the thickness of the wall of the torus varies between 0.6mm and 2mm, for example between 1.3mm and 2mm.

[63] Attached to the torus is a tubular body 220, with a diameter that varies along the axis of the tubular body 220. The wall thickness varies between 0.6 and 2mm, with a channel internally provided with diameter

13 BE2021/5987 of about 2.5mm, for example. The angle α between the axis 225 of the tubular body and the axis 211 of the torus is approximately 10°. The angle B between the center plane 212 of the torus 210 and the axis 225 of the tubular body 220 is approximately 100°.

[64] The tubular body is slightly bent near the connection point of the cylindrical body to the torus. At the connection of the tubular body and torus, the outer diameter of the tubular body is identical to the diameter of the circle whose revolution forms the torus. The wall of the torus defines and closes the channel of the tubular body at the connection point.

[65] The torus has a central opening 215 with a minimum or inner diameter 216 in the range of 5mm to 15mm; the torus has a maximum or outer diameter 217 in the range of 10mm to 20mm.

[66] At the connection of the channel of the tubular body and the torus, an opening 270 is provided on the inside of the torus.

[67] The product 100 is provided with a metal coating applied by vacuum coating.

[68] This product 100 is the outer ear part of an earplug. Pushed onto the side 222 of the tubular body is the plug of the earplug, which is conical and has a central cavity to receive the tubular body. The inside of the plug has recesses that correspond to the one or more coupling ribs 223. The plug can be made of silicone polymer, be frosted and optionally be provided with a dirt-repellent silicone layer.

[69] An acoustic filter can be provided on the side 222 of the tubular body. The filter is bonded to the side 222 of the tubular body with an adhesive, for example an acrylic adhesive. The filter is suitable for acoustic purposes and can consist of, for example, two layers.

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[70] It is understood that while the embodiments and/or the materials for providing embodiments of the present invention have been discussed, various modifications or changes may be made without departing from the scope and/or spirit of this invention. .

The present invention is by no means limited to the embodiments described above, but can be realized in various variants without departing from the scope of the present invention.

Claims (19)

15 BE2021/5987 Conclusions 1.- A method of manufacturing a product with an outer surface of at least two elements, the method comprising the steps of: e providing the two or more elements to provide the surface of the product; e assembling the two or more elements into an intermediate product, wherein seams between two or more elements are visible on the surface of the intermediate product; e coating the intermediate product until at least the seams are invisible, whereby multiple coating layers are applied, more than one or all of these multiple coating layers are applied by vacuum coating. A method according to claim 1, wherein all of these multiple coating layers are applied by vacuum coating. A method according to any one of claims 1 to 2, wherein at least one vacuum coated coating layer is a metal coating layer. A method according to any one of claims 1 to 3, wherein coating the intermediate product comprises applying a primer coating layer, applying the vacuum coated coating layer and applying a finishing layer. A method according to claim 4, wherein the primer layer has a thickness in the range of 11 to 20 µm, the coating layer has a thickness in the range of 12 to 18 µm and the finishing layer has a thickness in the range of 4 to 12 µm. A method according to any one of the preceding claims, wherein the two or more elements are polymeric elements. 16 BE2021/5987 7.- A method according to claim 6, wherein the polymeric elements comprise thermoplastic polymer. 8.- A method according to claim 7, wherein the polymeric elements comprise Acrylonitrile Butadiene Styrene (ABS). 9. A method according to any one of the preceding claims, wherein at least one of the two or more elements, and preferably all elements, are manufactured via injection moulding. 10.- A method according to any one of the preceding claims, wherein one or more pairs of adjacent elements are welded together by ultrasonic welding. 11. A method according to any one of the preceding claims, wherein the product comprises a hollow open torus, with a tubular body attached to the torus, whose outer wall connects to the torus. 12.- A method according to claim 11, wherein the axis of the tubular body and the axis of the torus form an angle (α) between 0° and 60°. A method according to any one of claims 11 or 12, wherein the product comprises an outer surface consisting of two elements. 14.- A method according to claim 13, wherein the first element comprises the tubular body and a first of two sections of the hollow open torus, which two sections are formed by cutting the hollow open torus with an imaginary cutting plane perpendicular to the axis of the hollow open torus, and the second element comprises the second of two sections of the hollow open torus. 15.- A method according to claim 14, wherein the two sections each form half of the torus. A method according to any one of claims 11 to 15, wherein the hollow open torus has an opening on the inside of the hollow open torus at the location where the tubular body attaches to the hollow open torus. 17 BE2021/5987 17.- A method according to any of the preceding claims, wherein the product forms part of an earplug. 18.- A method according to claim 17, wherein the product provides the outer portion of the earplug. 19. A method of manufacturing an earplug, the method comprising the steps of forming a product by a method according to any one of claims 1 to 18, the product comprising the outer ear portion of the earplug; e applying a plug to the outer ear part of the earplug.