US20130233477A1

US20130233477A1 - Method for manufacturing at least one part of a sole assembly of a shoe, and sole assembly for a shoe

Info

Publication number: US20130233477A1
Application number: US13/820,031
Authority: US
Inventors: Christian Bier; Stane Nabernik; Thorger Hübner; Tore Strömfors; Frank Jensen; Jakob Møller Hansen
Original assignee: Individual
Current assignee: Individual
Priority date: 2010-09-03
Filing date: 2011-06-16
Publication date: 2013-09-12
Also published as: CA2809324A1; AU2010360089A8; AU2011297907A1; WO2012028206A1; KR20130093116A; US20130160223A1; RU2013114837A; WO2012028348A1; EP2611323A1; KR20130101049A; CA2809317A1; AU2010360089A1; CN103338669A; RU2013114835A; CN103313618A; JP2013536772A; JP2013539388A

Abstract

The invention related to a method for manufacturing at least one part of a sole assembly (7) of a shoe (300) comprising the steps of directing a laser beam towards the at least one part of the sole assembly, which comprises a polymer material, and creating at least one of an opening (55), passage, cavity or engraved pattern in the at least one part of the sole assembly by means of the laser beam, or removing material from the at least one part of the sole assembly by means of the laser beam.

Description

The present invention is related to a method for manufacturing at least one part of a sole assembly of a shoe, and to a sole assembly for a shoe.
Products like shoes are typically mass produced in a way that leaves only little room for customization or fine tuning of details in the mass produced shoe. In order to obtain good economy and scale when manufacturing the shoe, the soles of the shoes are mass produced in high numbers and are almost looking the same. For manufacturing a sole of a shoe or the shoe as a whole, typically an aluminium block is milled to become a mould for a sole. Such moulds are expensive in material and work, and have to be made for the left and right foot respectively and for each shoe size. Thus, a considerable number of moulds have to be made for each sole design, which number of moulds in practice makes customization or fine tuning of a single shoe sole unrealistic. On the other hand, customization and fine tuning of single shoe soles may be desirable for the manufacturer to meet particular or changing customer demands.
It is therefore an object of the invention to provide a method for manufacturing a sole assembly of a shoe or parts thereof which is suitable of making customization or fine tuning of mass produced soles economically viable.
According to an aspect of the invention, there is provided a method for manufacturing at least one part of a sole assembly of a shoe according to the features of claim 1, and a sole assembly for a shoe according to the features of claim 21.
In particular, in an aspect of the invention there is provided a method for manufacturing at least one part of a sole assembly of a shoe comprising the steps of directing a laser beam towards the at least one part of the sole assembly comprising a polymer material and creating at least one of an opening, passage, cavity or engraved pattern in the at least one part of the sole assembly by means of the laser beam, or removing material from the at least one part of the sole assembly by means of the laser beam.
In a further aspect, there is provided a sole assembly for a shoe comprising at least one part which is manufactured from a polymer material, wherein the at least one part of the sole assembly comprises at least one of an opening, passage, cavity or engraved pattern created by means of a laser beam.
According to the invention, a laser beam generated by a laser apparatus may be used in the manufacturing of at least one part of a sole assembly of a shoe, for example for customizing the sole to particular needs or for working on particular parts of the sole assembly for creating one or more openings, passages, cavities or engraved patterns, or for removing left-overs of sole material from the sole casting or injection process. Advantageously, it is not necessary that a number of different moulds are made for manufacturing various sole designs, or that special moulds are manufactured which are provided with a number of pins or other projecting members for creating openings or passages. Rather, a single laser apparatus is sufficient for customization of different sole assemblies or parts thereof, which laser apparatus can be used not only for one type of sole design, but for various types of soles. By means of controlling the laser apparatus in a particular way, variable customization of mass produced shoe soles over various shoe types depending on the current needs may be performed in an economically viable way.
The use of laser in relation to shoes is essentially known in connection with roughing or engraving of the shoe upper, as well as for purposes of cutting leather. Laser is also used for measurement of foot size in order to manufacture custom made shoes. However, laser in connection with manufacturing of shoe soles which comprise polymer material has not been applied. As compared to an upper of a shoe, a polymer based sole is a different element which requires that the polymer material be manufactured and treated in a way that it is still able to withstand a wide variety of environmental influences which are particular for the shoe sole being the part of the shoe which carries the whole weight of the wearer and contacts the ground. The inventors of the present invention found that a polymer based sole of a shoe may be manufactured by use of a laser beam appropriately without compromising the properties of the sole with respect to these environmental influences.
As an example for creating an engraved pattern in the sole for customizing the same, the (mirrored) name of the human wearer may be engraved into the sole in the tread or on the side of the sole. According to another example, the letters of the manufacturer may be engraved, e.g., in the tread of the outsole. Also the shoe size could be engraved. Further, e.g. the country of origin, i.e. the country where the shoe was manufactured, could be engraved. Complex patterns or images such as a digitized photo of the wearer are also possible implementations for using a laser beam in the manufacturing of shoe soles.
A further advantage of using a laser in the manufacturing of a sole is that steps in the manufacturing process of the sole can be automated or improved in different ways. Thus, for example, the laser can be used for fine tuning or trimming the sole if left-overs from the sole casting or injection process are still adhered to the sole. E.g., the sprue extending from the heel of the sole and resulting from the injection of polyurethane can be cut away with the laser. This process is typically a manual operation, wherein by means of the present invention this process can also be automated and improved, such as the accuracy of removing left-over material. Further, for obtaining fast and simplified manufacturing steps, the laser can be used for creating openings, passages or through-holes, or cavities in the sole. For example, openings or passages can be used for ventilation purposes whereby the interior of the shoe is in air communication with the exterior for gaining breathability of the sole assembly.
According to an aspect of the invention, to increase the life time of the shoe sole, the at least one part of the sole assembly comprises a polymer material which is resistant to hydrolysis or contains material which is resistant to hydrolysis. The inventors found that the heat generating laser beam may destroy a potential protecting surface layer of the polymer material and hereby opens the material for entry of water. If the polymer material is not resistant to hydrolysis, the hydrogen atoms of water may react with the carbon atoms and any radicals of the polymer, if any, and may cause breakage of the chemical connections to the radicals over time hereby finally causing hydrolysis. As a result, the sole becomes pulverized over time and prone to mechanical damage at external impacts. After a certain period of time, it may be that the shoe cannot be used anymore. This problem is solved by using sole material that is resistant to chemical hydrolysis, or a sole material that contains material resistant to chemical hydrolysis.
According to an embodiment of the invention, the at least one part of the sole assembly comprises a polyurethane material based on a mixture of an isocyanate and a polyether.
According to another embodiment of the invention, the at least one part of the sole assembly comprises a polyurethane material based on a mixture of an isocyanate and a polyester based polyol, wherein one or more of hydrolysis preventing additives are added to the polyol. For example, one or more of the following hydrolysis preventing additives are added to the polyol: calcium and magnesium carbonate, or calcium and magnesium stearate, preferably in the range of 1% to 10% of the weight of the polyol including process additives, if any.
The inventors found that chemical hydrolysis may happen over the life time particularly in polyester based polyurethane sole material but not in polyether based sole material. The heat generating laser beam may destroy any protecting surface layer of the polyester based polyurethane and hereby opens the material for entry of water. The hydrogen atoms of water then react with the carbon atoms and the radicals of the polyester, which may cause breakage of the chemical connections to the radicals hereby finally causing hydrolysis.
Thus, according to an aspect of the invention, a polyurethane sole material based on a polyether polyol can be used to increase the life time of the shoe. Alternatively, a polyurethane material based on a polyester polyol can be used if hydrolysis preventing additives are added to the composition. Such additives can be calcium and magnesium carbonate totaling a weight percentage in the range of 1%-10% of the weight of the polyester polyol including process additives. Or it can be calcium and magnesium stearate with a total weight percentage of 1%-10% of the weight of the polyester polyol including process additives. This mixture will create a kind of pH-buffer which makes the sole more alkaline and prevents the eroding effect of an acidic hydrolysis attack on polyester based polyurethanes with no hydrolysis preventing additives.
In general the concentration of any hydrolysis preventing additives in the mixture should be low, because they may otherwise damage the reaction. A preferred method used for manufacturing a polyurethane based part of a sole makes use of, in a known way, two tanks, designated for example as tanks A and B. Tank A comprises the polyol, e.g. polyester or polyether, and process additives. According to the invention hydrolysis preventing additives may be added if the tank contains polyester. Tank B comprises the isocyanate. The materials of tanks A and B are typically mixed in the ratio A/B of 100 kg to 121 kg when injected into the sole mould. Alternatively, the materials of tanks A and B can be mixed as a pre-polymer prior to injection into the sole mould.
According to an embodiment, the at least one part of the sole assembly comprises a thermoplastic polyurethane, or a mixture of cork and polyurethane. The invention can be used on soles consisting only of polyurethane, or soles consisting of a mixture of polyurethane and cork. Particularly, a sole consisting of a thermoplastic polyurethane (TPU) can be used because the chemical properties are not changed by the laser process. This is due to the chemical crosslinks in the TPU.
The sole assembly can be adhered directly to the shoe upper in a direct injection process where the polyurethane is injected into a mould where the upper is placed, or the sole assembly can be pre-manufactured and in a later step adhered to the upper by means of gluing. The at least one part of the sole assembly manufactured with the aid of a laser beam can be the whole sole assembly attached below e.g. an insole of an upper assembly, i.e. comprising a tread or outsole engaging with the ground, or it can be the tread or outsole itself, or it can be a midsole which has an outsole attached to it or any other part of the sole. Possible outsoles can be made of TPU, Styrene Butadiene Rubber (SBR rubber), latex, pure cork, or cork pieces mixed with polyurethane.
According to a further embodiment of the invention, the method comprises the step of creating at least one opening or passage by means of the laser beam such that the opening or passage is connecting an interior of the shoe with an outside of the shoe e.g. for air ventilation of the shoe. Thus, such passages can be manufactured custom-made and in a precise way without requiring special moulds. For example, the laser beam creates said passage in a lateral side of the at least one part of the sole assembly, particularly in a lateral side of a midsole of the sole assembly.
For example, the opening or passage has a diameter in the range of 0.1 to 5 millimeters.
According to an embodiment, the point of laser beam focus is placed on a side wall of the at least one part of the sole assembly.
In a further embodiment of the invention, the method further comprises the steps of providing a ventilating sole element having a structure or material allowing for air flow through it, and creating at least one opening in a side wall of the ventilating sole element by means of the laser beam such that the opening is enabling air ventilation from an interior of the ventilating sole element to an outside of the shoe. According to an embodiment, the point of laser beam focus is placed on the side wall of the ventilating sole element.
The method may also comprise the step of creating at least one opening or passage in a side wall of a ventilating sole element, which has a structure or material allowing for air flow through it, by means of directing the laser beam through at least one opening or passage in the outsole or midsole (e.g., a surrounding sole element).
Furthermore, the method comprises the steps of creating a ventilating structure in a ventilating sole element, e.g. channels or passages.
Accordingly, the method of the invention is suitable for manufacturing a sole assembly for a wide variety of usage scenarios. The different components such as midsole, ventilating sole element, surrounding sole element and/or outsole etc., may be manufactured for a wide variety of usage scenarios in a way that they fulfill the particular demands. The interconnection between the structure or material of a ventilating sole element or a midsole and any passages in a surrounding sole element or in an outsole is made in a manufacturing step in which openings or apertures are made in a wall of the ventilating sole element or midsole by directing the laser beam through the passages. In this way, air and water vapour may effectively be transferred out of the shoe via the ventilating sole element or midsole and the passages in the outsole or surrounding sole element, since the laser formed openings in the ventilating sole element or midsole are then exactly aligned with the passages in the outsole or surrounding sole element.
The method of the invention may further comprise the step of creating at least one opening or passage in an outsole, midsole or surrounding sole element of the sole assembly. For example, the opening or passage has a diameter in the range of 0.1 to 5 millimeters.
According to an embodiment, the at least one part of the sole assembly comprises TPU, styrene butadiene rubber, latex or cork material, or any combination thereof.
The at least one of an opening, passage, cavity or engraved pattern may be formed in a lateral, medial, front or back side of the at least one part of the sole assembly.
According to an embodiment, the method may further comprise the step of creating at least one opening or passage in a side wall of a ventilating sole element, which has a structure or material allowing for air flow through it and which is at least partially surrounded by at least a portion of the sole assembly with at least one passage in it, by means of the laser beam directed through the at least one passage in the portion of the sole assembly surrounding the ventilating sole element, in particular the outsole, the midsole or the surrounding sole element.
In a possible implementation of the invention, the laser beam is controlled to generate a power output in a range between 50 W and 500 W at a speed in the range of 20 mm/s to 2000 mm/s.
For example, the laser beam is applied in a laser beam cycle which repeatedly scans over a portion of the at least one part of the sole assembly, wherein the laser beam cycle is repeated within the range of 5 to 30 times.
The method may include, in an embodiment of the invention, providing a controllable robot which is adapted to place the at least one part of the sole assembly in front of the laser beam, wherein the laser beam through a series of repeated laser cycles on the at least one part of the sole assembly creates the at least one of an opening, passage, cavity or engraved pattern, or removes material from the at least one part of the sole assembly.
For example, a point of focus of the laser beam is changed in steps in the following way: a) placing the target of the at least one part of the sole assembly in a point of focus, b) performing a first series of laser cycles which generate a channel with a first penetration depth, c) moving by means of the robot said at least one part of the sole assembly towards the point of focus so that the bottom of the channel is placed in the focus point of the laser beam, and d) performing a second series of laser cycles which deepens the channel in the sole.
According to a further embodiment, a first laser workstation may be used for roughing an upper of the shoe, whereafter the upper is placed in a mould and sole material is injected onto parts of the upper and hereby adhered to the upper, and whereafter the first laser workstation or a second laser workstation is used for creating the at least one of an opening, passage, cavity or engraved pattern, or removing material from the sole material.
For example, a robot is adapted to hold the element comprising at least one part of the sole, in front of a laser apparatus and the laser apparatus through a series of repetitive shots at the element burns away material of the element for making at least one opening, cavity, passage or a design in the element. The at least one opening, cavity or passage may have a length of between approx. 0.5 to 50 mm. The opening, cavity or passage may be formed as an air channel or guide for supporting an air flow therein from one end of the opening to the other.
For such use, different types of lasers can be used as, e.g., diode lasers, infrared lasers and CO2 lasers. In the following an embodiment of the invention will be described which makes use of a CO2 laser. CO2 lasers work with a wave length in the range of 9.4-10.6 micrometers. Usually, a laser is controlled by way of three parameters, such as speed (of the beam), quantity of energy and wavelength.
Making openings or patterns with a laser, particularly a CO2 laser, is possible in elastomeric, i.e. meltable materials such as polyurethane (PU), thermoplastic polyurethane (TPU), ethylene vinyl chloride (EVA), polyvinyl chloride (PVC) or rubber. In these materials the laser will, using a sufficient amount of energy, burn away the targeted sole material which will disappear without leaving debris.
Use of a laser for roughening of a shoe upper is described in DE 10 2009 049 776 A1.
When roughing shoe uppers of leather, techniques exist according to which the laser beam is swept across the surface of the upper in a predetermined time and with a predetermined amount of energy. The beam is swept by a mirror in the laser apparatus that deflect the laser beam in order to reach the surface of the shoe to be roughened while the robot holds the shoe upper in a fixed position during sweeping of the beam. The robot places the shoe in front of the laser and then the mirrors move the beam through the leather. During this process the robot is stopped. If the curvature of the shoe upper becomes too great, i.e. if the focus point of the laser beam is removed too much from the targeted spot, the shoe upper is repositioned anew by the robot. After repositioning, the new target spot is again in focus, and the laser sweeps across one or more spots.
A problem occurs, however, when deep openings in a (elastomeric) sole or part thereof shall be made. Such openings have a depth which is by far larger than the relatively shallow roughing made on leather uppers by the laser. For example, a lasered channel in a leather upper has a depth of 0.5 mm, whereas an opening in the sole may extend from the medial side of the sole to the lateral side, i.e. has a length of 50 mm. If the mirror-solution, which is used for roughing of the upper, with deflecting the laser beam is used for making openings in an element of a shoe, a problem may occur in opening any borders, such as the side wall of the ventilating sole element which may need to be provided with deep and narrow channels.
When using the mirror-solution the deflection of the beam may create an acute angle between the beam itself and the surface of the element. When applied for connecting narrow and elongated channels of lateral passages of a surrounding sole element to the structure or material of a ventilating sole element, such acute angle drives the beam sideways into the channel side wall of the lateral passages and it does not reach the bottom thereof facing the ventilating sole element.
On the other hand, according to an embodiment of the invention, the opening is made in an element of the sole, such as in the side wall of the ventilating sole element, by keeping the beam of the laser in a fixed direction (i.e. no sweeping of the laser beam) and letting the robot position the target spot of the element aligned with the center of the laser lens. This means that the laser beam will not be swept as when roughening a shoe upper. Instead only the robot arm holding the sole is moved. However, there may be applications in which a mirror may be used when making openings or making patterns in an element of a sole.
This method is thus especially useful if the laser beam is shot through a cylindrical passage already present in the sole as is the case if, e.g., the end of a passage in a sole, such as in a surrounding sole element, has to be opened.
According to an example a number of openings are made in a polyurethane sole. The sole material is polyurethane from manufacturer BASF GmbH. The polyurethane used has a relatively low density (0.35 g/cm3) and is often used for shoe midsoles. The following steps may be applied in various ways, in combination or individually depending on the particular implementation and needs. The terms “first, second . . . ” are used only for designation purposes and shall not impose any limitations as to sequence or numbers of steps.
(1) In a first step a sole is placed in front of the laser by a robot. (2) In a second step the target spot on the sole or element thereof is placed orthogonally to the laser beam by the robot. (3) In a third step the laser beam hits the sole material at an angle to the sole (element) surface of approximately 90 degrees. (4) In a fourth step the focus of the laser is kept constant, i.e. unchanged. (5) In a fifth step a series of laser shots towards the target spot is performed (e.g., multiple shots in the same place). The number of shots may be between 1 and 10 depending on the power of the laser and material and depth of entry. Duration per shot may be approx. 1 ms.
When applied for connecting the lateral passages of a surrounding sole element to the structure or material of a ventilating sole element, the laser shots may result in a diameter of the openings in the side wall of the ventilating sole element which equals the diameter of the passages made by pins of an injection mould in the surrounding sole element during injection. In order to get the desired diameter the number of shots can be varied as can the relative position of the shots. During a shot cycle the target can be moved a few millimeters (e.g., the robot moves), and the diameter will increase. In a further step, the robot moves the sole to the next target spot, i.e. the process goes to the second step (2) above.
In relation to the ventilating sole element, the opening of the side wall of the ventilating sole element with laser leaves no debris. Everything is burned away. Hereby any clogging of the air channels caused during manufacturing of the openings is prevented. The method further has the advantage that it is very fast compared e.g. to drilling out the openings.
In the following, particular embodiments and/or variations of the process making use of a laser for creating openings, passages cavities or patterns in a shoe sole are described:
In order to get a cylindrical opening, passage, cavity or pattern with a clean edge the amount of energy per shot may be increased. The focus point may be kept constant. The first laser shots start with a low energy for making a first opening or similar with a diameter of say 2 mm. The next series of shots has an energy increase of 50% per shot. The opening now has a diameter of 4 mm. The third series of shots has again an increase of energy by 50%, increasing the diameter at the beginning of the opening to 6 mm.
Alternatively, or simultaneously, the point of focus of the laser beam can be amended per shot or per series of shots. After a first series of shots the depth of the opening or similar—may be 3 mm. Now the focus has to be changed and moved 3 mm further inwards in the sole. Change of focus is made via software which controls the movement of the lenses in the laser apparatus.
Further, in order to ensure a well defined opening with a well defined edge, the laser beam can be moved in a spiral shape. Such spiral shape can be elliptical or circular. This functions the following way:

- A first series of shots in the centre of the target spot.
- The next series of shots in a neighbouring spot.
- And continuing in a spiral shape until an opening with the desired shape is achieved.

Ideally, in order to create a clean cut in a polyurethane sole, the diameter of the point of focus (spot size) may be between 0.5 mm and 2 mm and the power between 150 watt and 250 watt. It should be noted that these values are to be understood as pure examples without imposing any limitations in connection with the invention.
The robot may serve to position precisely any channels of a ventilating sole element in front of a laser. The robot is one of the preferred solutions because the openings are always in different positions—for instance, the position of a shoe with size 40 is different to the same shoe in size 41. A shoe sole is characterized by 3D-curvatures. It is not only a 2D surface, and therefore the focus point of the laser beam is changed along the 3D surface of the sole.

Aspects of the invention and further embodiments thereof are disclosed in the following description with reference to the drawings, in which:

FIG. 1 is an exploded three-dimensional view of main components of a shoe having a sole assembly, wherein parts of the sole assembly can be manufactured with a method according to the invention,

FIG. 2 is a schematic cross-sectional view of an embodiment of a shoe with passages or openings manufactured with a method according to aspects of the invention,

FIG. 3A-C show an embodiment of a mould and of a semimanufactured product formed in the process of manufacturing a shoe, the semimanufactured product comprising an exemplary outsole and ventilating sole element attached to the outsole,

FIG. 4A-C show a semimanufactured product of FIG. 3 in various process steps for manufacturing the finished shoe,

FIG. 5A-B show exemplary embodiments of laser apparatuses which may be used in the manufacturing of a part of a sole assembly of a shoe in accordance with aspects of the invention,

FIG. 6A-D show schematic results of an exemplary pattern manufactured on a part of a sole assembly according to aspects of the invention,

FIG. 7A-C show further schematic results of exemplary patterns manufactured on a part of a sole assembly according to aspects of the invention,

FIG. 8 shows a schematic view of a manufacturing principle in accordance with aspects of the invention for forming ventilating openings in a part of a sole assembly.

In the following, exemplary embodiments of a method according to the invention applied in the manufacturing of an exemplary shoe will be described. The skilled person will be aware that various changes or adaptations may be made as far as appropriate and depending on the particular needs of the respective shoe or sole construction.
As described in the following in more detail, the principles of manufacturing of at least parts of a sole assembly of a shoe by means of a laser beam in accordance with the invention may be applied basically to any kind of shoe. In an aspect of the invention, the method may be applied to a kind of sole assembly of a shoe as shown in FIGS. 1 and 2. In order to better understand the structure and function of the respective parts of the sole assembly and the particulars involved in the laser beam manufacturing, at first an explanation will be given as to the structure and function of the main elements of the shoe.
FIG. 1 shows an exploded three-dimensional view of main components of a shoe 300 according to an embodiment. The shoe 300 comprises a sole assembly 7 and an upper assembly 8. The sole assembly 7 in turn comprises, from bottom to top in the exploded view, an outsole 90, a shank 172, a ventilating sole element 60, a comfort layer 40, and a surrounding sole element 80.
The position of a vertical plane including horizontal line Y-Y corresponds to the position of the cross-sectional plane depicted in FIG. 2. It is pointed out that the embodiment of FIG. 2 is different from the shoe 300, but that the position and viewing direction of the depicted vertical cross-sectional plane can be inferred from the line Y-Y and the associated arrows, which represent the viewing direction.
The outsole 90 comprises a tread or corrugated structure on its lower surface for improving the grip characteristics of the shoe during walking. The shank 172 is provided in the shoe 300 to give it additional stability. The shank 172 is optional and may be made of metal or any other suitable material. Due to the illustrative nature of FIG. 1, the shank 172 is shown as a separate element. However, in most embodiments, the shank 172 is positioned within the ventilating sole element 60.
The ventilating sole element 60 comprises a channel structure, in particular a channel grid, at its upper side. The channel structure comprises transverse channels, generally designated with reference numeral 181. Channels 184 cross the transverse channels 181.
A distinction is made between at least one peripheral channel being formed in a peripheral region of the channel structure and longitudinal channels. For the sake of simplicity in describing different shoe constructions, the channels 184 are generally referred to as longitudinal channels, although one or more of the channel cross-sections shown may belong to one or more peripheral channels.
The ventilating sole element 60 has an upper surface 606, a lower surface 604 and a lateral surface 602. In an assembled state of the shoe 300, the lower surface 604 of the ventilating sole element 60 is partly adjacent the shank 172 and partly adjacent the outsole 90, the upper surface 606 of the ventilating sole element 60 is adjacent the comfort layer 40, and the lateral surface 602 of the ventilating sole element 60 is adjacent a lateral inner surface 802 of the surrounding sole element 80. Regarding the engagement/connection of the individual components, more details are given below.
The channel structure, in particular the transverse channels 181, is in air communication with a plurality of openings 55. The openings 55 extend through a side wall of the ventilating sole element 60, particularly they extend from the channel structure of the ventilating sole element 60 to lateral passages 50 of the surrounding sole element 80.
The surrounding sole element 80 has a varying height across its circumference, with the lateral passages being arranged at different heights. In this way, the positions of the lateral passages account for the uneven surface structure of the ventilating sole element 60, which takes into account the wearer's foot and its positioning during walking. Exemplary embodiments of the components are described in greater detail below.
FIG. 2 is a schematic cross-sectional view of a shoe 301 a in accordance with an embodiment. FIG. 2 is in particular schematic in that it shows a u-shaped shoe portion. It is apparent to a person skilled in the art that the shoe is closed on top, in particular in a forefoot region.
The shoe 301 a comprises an upper assembly 8 and a sole assembly 7. The upper assembly 8 has an upper portion 10 and a bottom portion 20. The upper portion 10 comprises, from outside to inside, a breathable outer material 11, also referred to as upper material, a mesh 12, an upper membrane 13, and a textile lining 14. The mesh 12, the upper membrane 13 and the textile lining 14 are provided as a laminate, also referred to as upper functional layer laminate 17. The upper membrane 13 is breathable and waterproof. With all of the upper material 11, the mesh 12 and the textile lining 14 being breathable, i.e. water vapour permeable, the upper portion 10 as a whole is breathable and waterproof.
The upper material 11 may be any breathable material suitable for forming the outside of a shoe, such as leather, suede, textile or man made fabrics, etc.
The upper functional layer laminate (i.e. mesh 12, upper membrane 13 and textile lining 14) may be any suitable waterproof and breathable laminate, such as commercially available GORE-TEX® laminate from W.L. Gore & Associates.
A lower portion of the outer material 11 is comprised of a netband 15. The netband 15 may be attached to the remainder of the outer material 11 through any suitable way of connection, for example stitching or gluing. In the exemplary embodiment of FIG. 2, the netband 15 is attached to the remainder of the outer material 11 via stitching 16, as illustrated by a connecting line. As the term netband suggests, this portion of the outer material is not a continuous material, but comprises voids in the material that allow for the penetration of fluid sole material therethrough, as will be explained later. Instead of providing a netband, the lower portion may also be comprised of the same material as the remainder of the outer material, with the voids being generated by puncturing or perforating the outer material in the lower portion.
The bottom portion 20 comprises, from bottom to top, a lower membrane 21 and a supporting textile 22. The textile may be a woven, non-woven or knitted textile, for example Cambrelle®. The lower membrane 21 and the supporting textile 22 are provided as a laminate, also referred to as bottom functional layer laminate 24. The lower membrane 21 is waterproof and breathable. With the supporting textile 22 being breathable, an overall breathable and waterproof bottom functional layer laminate 24 is provided. The bottom functional layer laminate 24 may be any suitable laminate, for example commercially available GORE-TEX® laminate from W.L. Gore & Associates.
The upper portion 10 and the bottom portion 20 are connected to each other at their respective end areas. Particularly, a lower end area of the upper functional layer laminate 17 is connected to a side end area of the bottom functional layer laminate 24. In the embodiment of FIG. 2, this connection also connects an end area of the netband 15 to the upper functional layer laminate 17 and the bottom functional layer laminate 24. The bottom functional layer laminate 24, the upper functional layer laminate 17 and the netband are stitched together, for example by a strobel stitch or a zigzag stitch. Accordingly, a connection 30, also referred to as bond 30, in the form of a sewn or stitched seam is formed connecting the bottom functional layer laminate 24, the outer material 11 (via the netband 15) and the upper functional layer laminate 17. This seam 30 is sealed in a waterproof manner by sole material, as will be explained later, such that a waterproof structure is formed by the upper portion 10 and the bottom portion 20.
The upper functional layer laminate 17 and the bottom functional layer laminate 24 may be positioned end-to-end before being connected and sealed together, as shown in FIG. 2. Both laminates may also be bent downwards, such that respective portions of the upper sides of the laminates are positioned adjacent each other. In these different positions, the laminates may be connected, for example through stitching as shown, and the connection region may be sealed. The netband 15 of the outer material 11 may be positioned corresponding to the upper functional layer laminate 17, i.e. in an end-to-end or overlap or bent relation with respect to the bottom functional layer laminate 24, such that the connection 30 also connects the netband 15 to the bottom functional layer laminate 24 and the upper functional layer laminate 17. The netband 15 may also extend through the connection 30, which is uncritical due to its porous structure. These different options for forming the connection 30 may be applied to all embodiments described herein.
In the embodiment of FIG. 2, the connection 30 between the upper functional layer laminate 17 and the bottom functional layer laminate 24 is located at the substantially horizontal portion of the inside of the shoe 301 a, which is intended to support the underside of the wearer's foot. In the cross-sectional plane of FIG. 2, the connection 30 is close to the lateral end of said substantially horizontal portion, i.e. close to the point where the portion for supporting the weight of the foot transitions into the side wall of the shoe. Due to the nature of the shoe 301 a, the bottom functional layer laminate 24 is a substantially foot-shaped structure, with the upper functional layer laminate 17 being connected thereto perimetrically. It is pointed out that the terms horizontal and vertical refer to the horizontal and vertical directions present when the shoe is placed with the sole on an even ground.
The sole or sole assembly 7 of the shoe 301 a, i.e. the portion of the shoe 301 a below the upper assembly 8, which consists of the upper portion 10 and the bottom portion 20, is comprised of a ventilating sole element 61, a comfort layer 40 and a surrounding sole element 81.
The ventilating sole element 61 comprises a channel structure 160 that allows for air communication between the upper side of the ventilating sole element 61 and openings 55. Lateral passages 50 extend through a side wall 702 of the surrounding sole element 81 and the openings 55 extend through a side wall 608 of the ventilating sole element 61. For an easier reading of FIG. 2, the reference numerals 608 and 702 are provided with brackets illustrating lateral extensions of the side wall of the ventilating sole element and side wall of the surrounding sole element, respectively. It is, however, understood that the reference numerals 608 and 702 are meant to denote the side wall of the ventilating sole element and the side wall of the surrounding sole element themselves. The channel system 160 of the embodiment of FIG. 2 comprises a plurality of longitudinal channels 184, arranged in the longitudinal direction of the shoe 301 a, and a plurality of transverse channels 181, arranged in the transverse direction of the shoe 301 a, i.e. in the direction orthogonal to the longitudinal direction of the shoe.
The cross-sectional view of FIG. 2 cuts through a transverse channel 181 of the channel structure 160 along the horizontal line Y-Y of FIG. 1. Therefore, the transverse channel 181 of the ventilating sole element 61 is not shown in a shaded manner, as the cross-sectional cut reaches through the open channel. In contrast thereto, the portions of the ventilating sole element 61 surrounding the channel structure 160 and the surrounding sole element 81 are shown in a shaded manner illustrating that the cross-section of FIG. 2 slices through these shoe elements in the depicted cross-sectional plane. Correspondingly, the upper assembly 8 and the comfort layer 40 are shown in a shaded manner.
In the cross-sectional view of FIG. 2, the longitudinal channels 184 are seen in their cross-sectional shape, which is a u-shape reaching from the upper surface 606 of the ventilating sole element 61 some distance towards the lower surface 604 of the ventilating sole element 61. The transverse channel 181 cut in the cross-section of FIG. 2 is confined by a surface made of the portions between the longitudinal channels lying behind the cross-sectional plane. Accordingly, the transverse channel 181 depicted extends longitudinally behind the cross-sectional plane of FIG. 2, with the non-shaded portions of the ventilating sole element 61, which surround the u-shaped longitudinal channels 184, forming a trans-verse boundary surface. Only the u-shaped longitudinal channels 184 form a longitudinal air flow permitting connection to further transverse channels behind and in front of the cross-sectional plane of FIG. 2.
The u-shape of the longitudinal and transverse channels allows for a good compromise between providing sufficient channel volume for fluid communication and providing a strong ventilating sole element structure for supporting the wearer's foot and transferring the wearer's weight to the ground and/or the surrounding sole element 81. Also, the u-shaped channels can be manufactured easily and quickly, particularly in the case of an injection-moulded ventilating sole element 61, because the rounded channel side walls allow for an easy parting of the ventilating sole element 61 and the mould after the moulding operation. Of course the channels may also be manufactured using a laser beam.
It is pointed out that the channels of the ventilating sole element 61 may have any suitable cross-section that allows for an efficient transfer of water vapour from the upper side of the ventilating sole element 61 to the lateral passages 50 in the surrounding sole element 81. At the same time, the ventilating sole element 61 should provide a stable structure for the sole of the shoe. It is also pointed out that the channels may have varying cross-sections along their length in order to form a channel system having desired properties.
The exemplary embodiment of FIG. 2 comprises five longitudinal channels 184, which are distributed across the width of the ventilating sole element 61 in a uniform manner. It is also possible that the longitudinal channels have varying widths and/or are distributed non-uniformly across the width of the ventilating sole element 61. Further, it is possible that these channels are at an angle with respect to the longitudinal direction of the shoe 301 a, such that any suitable channel structure 160 may be formed.
The transverse channel 181 connects the longitudinal channels 184 to each other and to the openings 55 and lateral passages 50 in the surrounding sole element 81. At its lateral ends, the transverse channel is equipped with air and moisture discharging ports 182. The air and moisture discharging ports 182 are arranged laterally outside from the laterally outmost longitudinal channel. In particular, the air and moisture discharging ports 182 are arranged directly adjacent the side wall 608 of the ventilating sole element 61. The air and moisture discharging ports 182 are formed by recesses in the floor of the transverse channels 181. In other words, the floor of the transverse channels 181 extends deeper down into the ventilating sole element 61 in the region of the air and moisture discharging ports 182 than throughout the remainder of the transverse channels 181. The air and moisture discharging ports 182 allow for an efficient collection of moisture/water vapour from the inside of the shoe, from where the water vapour can be carried away effectively through the openings 55 and lateral passages 50. All or only a subset of the transverse channels may 181 have air and moisture discharging ports. The ports too may be manufactured by the use of a laser beam.
All or only a subset of the transverse channels 181 may provide for the connection with openings 55 and lateral passages 50. There may also be transverse channels 181 that are not in air communication with openings 55 and lateral passages 50, but end in dead ends. The transverse channels of the ventilating sole element 61, one of which is being shown in FIG. 2, allow for air communication between the channel system 160 of the ventilating sole element 61 and the openings 55 and lateral passages 50 extending through the side walls 608 and 702, respectively. With the bottom functional layer laminate 24 being breathable, water vapour transport from the inside of the shoe to the lateral outside of the sole 7 is ensured through the ventilating sole element structure, which allows the water vapour containing air to pass through it.
It is pointed out that the transverse channels 181 may have the same, a smaller or greater height than the longitudinal channels 184. They may be channels that reach from the top of the ventilating sole element towards the inside of the ventilating sole element, such that they can also be seen as grooves or tranches. It is also possible that the transverse channels lie below a portion of the ventilating sole element 61 and are therefore not readily visible from the top of the ventilating sole element 61. Also, the longitudinal channels may be grooves, as shown, or channels concealed from the upper surface of the ventilating sole element 61.
In the present embodiment, the channel system 160 of the ventilating sole element 61 is a channel grid. The channels of the channel grid extend from the top of the ventilating sole element 61 to the inside thereof. The channels may be longitudinal channels 184 and transverse channels 181, which intersect for allowing air communication therebetween. The channels may also be diagonal channels, when seen from the top of the ventilating sole element. In general, such a channel grid may have any combination of longitudinal, transverse and diagonal channels.
It is pointed out that any channel structure may be embodied in all other constructions of the remainder of the shoe, in particular in combination with all other upper assembly constructions and all other constructions relating to the remainder of the sole 7.
The lateral passages 50 extend through the side wall 702 of the surrounding sole element 81 and the openings 55 extend through a side wall 608 of the ventilating sole element 61 of the shoe 301 a, allowing for air communication between the channel structure of the ventilating sole element 61 and the lateral outside of the shoe 301 a. In the exemplary embodiment of FIG. 2, the lateral passages 50 and openings 55 are depicted as transverse passages and openings being horizontal. However, the terms lateral passage and openings may not be understood in such a restricting manner. A lateral passage or opening may be any passage or opening, respectively, that allows for an air communication between the inside of the ventilating sole element and a lateral outside of the surrounding sole element, i.e. the outside of the surrounding sole element that is not the underside of the shoe 301. The principles of the invention, however, may also be applied with any kind of opening, cavity or passage, including those which are open to the underside of the shoe. In the present embodiment, the lateral passages 50 and/or openings 55 may be inclined with respect to the horizontal direction, in particular with the outer end lower than the inner end of the ventilation passage. This inclination has the advantage that water can drain out more easily from the ventilating sole element and surrounding sole element. However, horizontal lateral passages and openings have the advantage of providing a favourable path for air or water vapour flow, particularly if a continuous passage from the right side of the ventilating sole element to the left side of the ventilating sole element or vice versa is present. The lateral passages 50 and/or openings 55 may also be inclined with the outer end being higher than the inner end of the ventilation passage. This helps when creating the openings by laser operation without any danger of damaging the delicate membrane 21 of the bottom functional layer laminate 24. Moreover, water vapour, which is warm due to the wearer's body temperature, may effectively exit the ventilating sole element through such inclined lateral passages in a chimney-like manner. When viewed from the top of the ventilating and surrounding sole element, the lateral passages 50 may be in a longitudinal direction of the shoe, in a transverse direction of the shoe, or in any direction therebetween. For example, in the front or the back of the shoe, the ventilation channels may be substantially in a longitudinal direction of the shoe.
The ventilating sole element 61 of the shoe 301 a also comprises a circular lip 101. The circular lip 101 is arranged at the upper lateral edge of the ventilating sole element 61. As the ventilating sole element 61 is a three-dimensional structure, the circular lip 101 surrounds the perimetric upper edge of the remainder of the ventilating sole element 61. In other words, the circular lip 101 is arranged at the periphery of the upper lateral portion of the ventilating sole element 61. Accordingly, the term circular is not intended to be understood as referring to the shape of a circle. Instead, it is understood as referring to a structure surrounding an inner space or as referring to a loop structure. However, the term is also not intended to require a closed lip or collar structure. The lip may be continuous around the perimeter of the ventilating sole element 61, but is may also be made of a plurality of spaced apart lip sections distributed around the perimeter of the ventilating sole element 61. The lip also does not need to be arranged right at the upper lateral edge of the ventilating sole element 61. It may also be attached to the lateral surface 602 or the upper surface 606 thereof. However, a positioning in the vicinity of an upper circumferential edge of the ventilating sole element may be beneficial, as will be discussed below.
The circular lip 101 may perform one or more of the functions described as follows. As shown in FIG. 2, the circular lip 101 extends to the position of the connection 30. The connection 30 includes the circular lip 101, such that it connects the upper portion 10, the bottom portion 20 as well as the ventilating sole element 61. In particular, the strobel stitch 30 connects the upper functional layer laminate 17, the netband 15 of the upper material 11, the bottom functional layer laminate 24 and the circular lip 101 of the ventilating sole element 61. Hence, the circular lip 101 allows for an attachment of the ventilating sole element 61 to the upper assembly 8. This attachment is independent from the attachment of the ventilating sole element 61 to the upper assembly 8 via the surrounding sole element 81. During the manufacture of the shoe 301 a, the ventilating sole element 61 may be attached to the upper assembly 8 in a fixed position through the connection 30 along the circular lip 101, which may also leave the comfort layer 40 in a fixed position. This allows for a more accurate production of the shoe 301 a, as the fixed position of the ventilating sole element 61 ensures that the surrounding sole element 81 surrounds the ventilating sole element 61 in the desired manner and location.
It is also possible that the ventilating sole element 61, comprising the circular lip 101, is attached to the upper assembly by gluing the circular lip 101 onto the upper assembly 8 or by effecting an attachment between the circular lip 101 and the upper assembly 8 through a local injection-moulding operation in the region of the circular lip 101, particularly only in the region of the circular lip 101.
The upper portion of the surrounding sole element 81 is located above the circular lip 101 of the ventilating sole element 61, i.e. below a part of the bottom functional layer laminate 24, as well as underneath the circular lip 101 and underneath a part of the upper portion 10 of the upper assembly 8 as well as adjacent a part of the upper portion 10 of the upper assembly 8 that is arranged in a substantially vertical direction. In other words, the surrounding sole element 81 wraps around the corner of the upper assembly 8 where the inside of the shoe is patterned to match a wearer's foot. In yet other words, the surrounding sole element 81 covers a part of the underside of the upper assembly 8 as well as parts of the lower lateral sides of the upper assembly 8. Sole material of the surrounding sole element 81 is penetrated through the netband 15, through the strobel stitch 30, through the mesh 12, onto the upper material 11, onto the upper membrane 13, around at least a portion of the circular lip 101 and onto the bottom membrane 21. This penetrated sole material seals the strobel stitch 30 in a waterproof manner on the one hand and attaches the ventilating sole element to the upper assembly 8 on the other hand. The sealing provides a completely waterproof upper assembly 8 made up of the upper functional layer laminate 17 and the lower functional layer laminate 24 surrounding the interior of the shoe and being sealed in a waterproof manner to each other. The sealed upper functional layer laminate 17 and bottom functional layer laminate 24 form a waterproof, breathable functional layer arrangement. Thus the upper assembly 8 is waterproof, which allows the sole assembly to be non-waterproof. The surrounding sole material also penetrates through the connection 30 to the upper sides of the bottom functional layer laminate 24 and the upper functional layer laminate 17, which is illustrated by the circle sector covering the upper side of the strobel stitch 30 and extending onto the bottom functional layer laminate 24 and the upper functional layer laminate 17 in FIG. 2. In particular, the surrounding sole material penetrates through the space between the two laminates upwards. The surrounding sole material also penetrates somewhat in between the circular lip 101 and the bottom functional layer laminate 24. In this way, the whole region of the strobel stitch 30 is penetrated with surrounding sole material, such that all holes generated in the upper membrane 13 and the bottom membrane 21 through the strobel stitching operation are reliably sealed by surrounding sole material. However, the penetrating surrounding sole material is kept to such a low volume that the comfort for the wearer as well as the breathability of the upper assembly 8 is essentially unimpeded.
Above the ventilating sole element 61, a comfort layer 40 is provided in the shoe 301 a. The comfort layer 40 is positioned on top of the ventilating sole element 61. The comfort layer 40 may be loosely positioned there or may be attached before further manufacturing of the shoe. Such attachment may be achieved by a spot-gluing or circumferential gluing or by gluing making use of breathable glue, such that the flow of water-vapour from the inside of the shoe to the ventilating sole element 61 is not prevented. Also, the full surface of the ventilating sole element 61 can be glued, and in order to prevent glue to enter the channels a highly thixotropic glue should be used. The comfort layer 40 is inserted for increasing the soft walking feel for the wearer, particularly for ensuring that the wearer does not feel bothered by the channel system 160 of the ventilating sole element 61. In the exemplary embodiment of the shoe 301 a, the comfort layer 40 has a greater lateral extension than the channel system 160 of the ventilating sole element 61 and extends somewhat above the region of the circular lip 101. However, the comfort layer does not extend to the lateral edges of the circular lip 101 where it is attached to the upper assembly 8. In general, the comfort layer may have the same or smaller or larger lateral dimensions as/than the ventilating sole element.
The ventilating and surrounding sole elements are produced and attached to the upper assembly 8 in a several stage process. As a first step, the ventilating sole element 61 is produced, for example through injection-moulding of a polyurethane (PU) into a mould with the channels being produced either by the mould being shaped accordingly or by the use of a laser beam. Polyurethane is one of a plurality of suitable materials that can be used in order to form a ventilating sole element 61 that has high stability to support at least a portion of the weight of the wearer during use, such as during walking, while having some flexibility in order to enhance the wearer's comfort during walking. Depending on the preferred use of the shoe, a suitable material can be chosen. Examples of such materials besides polyurethane is EVA (Ethylene Vinyl Acetate). etc.
As a next step, the comfort layer 40 is placed on top of the ventilating sole element 61 and attached to it using an adhesive. The ventilating sole element 61 and the comfort layer 40 are then placed in the desired position with respect to the upper assembly 8 in a mould, wherein the surrounding sole element material is injection-moulded onto the upper assembly 8 and the ventilating sole element 61. In this way, the surrounding sole element 81 adheres to the upper assembly 8 as well as to the sole ventilating element 61, such that a lasting, integral joint of these elements is achieved through the sole material of the surrounding sole element 81. Suitable materials for the surrounding sole element are polyurethane, EVA, PVC or rubber, etc.
In the embodiment of FIG. 2, the netband 15 wraps around the corner of the upper portion 10, i.e. the part of the upper portion 10 where the upper functional layer laminate 17 and the netband 15 of the upper material 11 are bent from a substantially horizontal orientation to a substantially vertical orientation. The part having a substantially vertical orientation forms the side walls for the wearer's foot. Accordingly, the sole material of the surrounding sole element 81 may penetrate through the netband 15 and onto the upper membrane from the underside and from the lateral sides of the upper assembly 8. In this way, a strong, multi-directional attachment between the surrounding sole element 81 and the upper functional layer laminate 17 is achieved, as well as a good seal provided between the laminates 17, 24.
In the exemplary embodiment of FIG. 2, the surrounding sole element 81 reaches further down than the ventilating sole element 61, which leads to a supporting of the wearer's weight by only the surrounding sole element 81 on a plane surface. This may be desired, as only a portion of the sole needs to be designed for continuous load bearing of the wearer, whereas the material used for the ventilating sole element 61 may be chosen based on the manufacturing characteristics for producing the channel system 160 and/or based on a minimisation of weight of the ventilating sole element 61 and therefore of the centre portion of the sole 7 of the shoe 301 a in which the ventilating sole element 61 is situated.
Even though, according to the exemplary embodiment of FIG. 2, the sole 7 of the shoe 301 a is not shown to have an outer sole, it is pointed out that such an additional sole element could be provided therewith. Also, the undersides of the ventilating sole element 61 and the surrounding sole element 81 are not provided with a tread structure for improving the grip of the sole assembly 7 on the ground during use of the shoe. It is, however, pointed out that tread elements may be provided at the underside of the sole in all embodiments described. Such tread elements may e.g. be formed by the use of a laser beam.
In the following, an exemplary method for manufacturing a shoe in accordance with principles of the invention will be described. The skilled person will be aware that various changes or adaptations may be made in manufacturing the shoe as far as appropriate and depending on the particular needs of the respective shoe construction.
In a process of forming an upper assembly, a bottom portion 20 of the upper assembly is attached to an upper portion 10 thereof. This can be done in any suitable way, for example using commonly known methods such as gluing, stitching etc. For example, the bottom portion may comprise a breathable insole or a waterproof, breathable functional layer laminate with a membrane being waterproof and water vapour permeable. The bottom portion may extend between lower end areas of the upper portion such as shown in the examples of FIGS. 1 and 2. Particularly, the bottom portion may be seen as the lower part of the upper assembly extending between the seams 30. Accordingly, it may encompass also parts of the side portions of the upper assembly.
In the examples of FIGS. 1 and 2 as described above, the bottom portion 20 of the upper assembly comprises a waterproof, breathable bottom functional layer laminate. In an embodiment, a 2-layer bottom functional layer laminate is stitched (“strobeled”) to a waterproof, breathable upper functional layer laminate at a stitched seam 30 according to the Strobel method as described above. For example, the laminate may have a textile layer 22 on top towards the foot and a membrane, which is waterproof and breathable, below towards the sole.
In the process of forming a sole assembly, an outsole, e.g. of rubber, is made in a respective manufacturing step as commonly known. The rubber is vulcanized and shaped into an outsole. Afterwards, the outsole may optionally be chemically primed by brushing “TFL Primer” (commercially available from the company Forbo Adhesives) on the surface facing the foot. Priming is carried out on open rubber cells in a well known manner to improve the connection to the polyurethane of the ventilating sole element which is later injected. After such priming, glue (for example, Helmipur® GPU from Forbo Adhesives) is applied to that area of the outsole where the ventilating sole element is to be placed later. The outsole is dried for a particular period of time as necessary, for example half an hour at 25-40° C.
In a further step, the outsole is then placed on a piston of a mould, which is in the present embodiment a first injection form or mould and is shaped to mould the ventilating sole element. An exemplary injection mould 210 is shown in FIG. 3A. It comprises side frames 211 which are shown in a closed position surrounding a bottom portion 213 of the mould. The structure visible on top of the bottom portion 213 is arranged to form the channel structure in the ventilating sole element, as can been seen in FIG. 3C with channel structure 162. The outsole may be placed on another part of the mould 210, for example on a top piston as the top part of the mould. For example, as shown in FIG. 3B, an outsole 191 is placed on top of a top piston 212 of the mould 210. In a subsequent step, the side frames 211 of the mould 210 close from an opened state into the state as shown in FIG. 3A, wherein the top piston 212 with the outsole 191 facing the inner space of the mould is lowered and seals the mould 210 from the top (not shown).
Afterwards, the material forming the ventilating sole element, such as polyurethane, is injected into the mould 210. In an embodiment of the invention, this may be the same polyurethane which is used for a surrounding sole element (which may also be seen as a midsole) later on. In another embodiment the polyurethane of the ventilating sole element is softer (Shore A value of e.g. 30-45) than a polyurethane used for the surrounding sole element (Shore A value of e.g. 45-65). This increases comfort for the wearer. During injection the formed ventilating sole element is bonded to the outsole. After completion of the injection process, these two components now form a monolithic entity, as can be seen in FIG. 3C. Subsequently, the edges of the ventilating sole element may be manually treated for superfluous material, if any, or left-over material may be removed by use of a laser beam of a laser apparatus.
The manufacturing steps as described above may be performed and finished in a particular manufacturing site independently from other parts of the shoe, for example by a sub-supplier, who will deliver to the shoe manufacturer, for instance, a finished semimanufactured product comprising the ventilating sole element attached to an outsole. An embodiment of a ventilating sole element 161 attached to an outsole 191 is shown in FIG. 3C. In other embodiments, according to the aspects as described with reference to FIGS. 1 and 2, a semimanufactured product comprising any type of ventilating sole element with or without an outsole component and/or stilts may be manufactured in a first stage of a manufacturing process, e.g. by a sub-supplier.
As illustrated in FIG. 4A, a breathable comfort layer 40 is fixed on the surface of the ventilating sole element, e.g. by glue being manually spread on the edge of the ventilating sole element or over parts of or the full surface of the ventilating sole element. According to an embodiment, before assembling the material on the ventilating sole element, mechanical pressure is applied to the material, which is compressed, e.g., from 2 mm to 1 mm in thickness. This may be done to make the material more compact and hence to lower the amount of water absorbed. This advantageously prevents the material from acting as sponge which nurtures growth of fungus and the like.
The ventilating sole element with the outsole and the comfort layer is then placed in an injection mould, such as a second injection mould 220 as shown in FIG. 4B. For example, the outsole 191 with the ventilating sole element 161 and the comfort layer 40 is placed on top of a bottom piston 222. With the second injection mould the surrounding sole element is formed in injection process. In this particular example, the second injection mould 220 incorporates pins 221 in the side frames for making lateral passages in a surrounding sole element.
At the beginning of the moulding process, the last with the upper portion 10 of the shoe is lowered into the second injection mould 220. The bottom piston 222 is then raised until the ventilating sole element has firm contact with the bottom portion 20 of the shoe upper assembly placed on the last. The contact between ventilating sole element with comfort layer and the bottom portion 20 must be so tight that polyurethane from the upcoming injection does not enter between bottom portion 20 and comfort layer. In order to achieve a tight sealing a lip extends vertically from the surface of the ventilating sole element. The lip could be arranged around the full upper circumferential edge of the sole element, but preferably a U-shaped lip of approx 2 mm height is made in the heel area, and a 1 mm high lip is made in the forefoot area. When raising bottom piston 222 against bottom portion 20 an extra mechanical pressure is exerted on the lip in order to deform it a bit. Due to the force impact the lip will bend outside and away from the ventilating sole element, and with the aid of the comfort layer make a tight seal which prevents entry of polyurethane. After raising the bottom piston the side frames with pins 221 close the mould 220, as shown in FIG. 4C. The pins 221 contact the side wall of the ventilating sole element so as to form lateral passages 50 in the surrounding sole element to be injected, but do not penetrate it.
Thereafter, an injection with surrounding sole material, particularly PU, is made, hereby creating a surrounding sole element. After a certain curing time (e.g. 3.5 minutes) the side frames are opened and last with the shoe is lifted. Any remaining sprue is manually removed from the surrounding sole element with a knife or automatically with a laser beam.
In a subsequent step, openings 55 are made in the side wall of the ventilating sole element, e.g. with a laser beam as outlined in more detail below with reference to FIG. 8.
According to another embodiment, if no pins 221 are provided in the second injection mould 220, the lateral passages 50 in the surrounding sole element and the openings 55 in the side wall of the ventilating sole element may be made with a laser beam which removes wall material appropriately, for example in a process as described in more detail below.
The creation of openings 55 in the side wall of the ventilating sole element connects the lateral passages 50 of the surrounding sole element to the structure or material of the ventilating sole element, so that water vapour can flow and/or diffuse through the bottom portion of the upper assembly and then flow through the structure or material of the ventilating sole element together with the air flowing therethrough and then through the lateral passages in the surrounding sole element to the outside of the shoe, that is the ambient air. The structure or material of the ventilating sole element and the lateral passages in the surrounding sole element are interconnected by making apertures or openings in the ventilating sole element through the lateral passages, so that thereafter there is a reliable path for air to communicate between the structure or material of the ventilating sole element and an outside of the surrounding sole element, that is the ambient air.
In the following, a possible implementation for making openings, passages or cavities in a part of a sole assembly of a shoe, or for removing material from a sole assembly is described by way of examples.
For example, in the manufacturing of at least one part of a sole assembly the following two embodiments of laser work stations may be used. First as shown in FIG. 5A, there is provided a laser work station 70 with a laser apparatus 71 (in the present example, a CO2 laser) and a non-moving sole target 76, which is at least one part of a sole assembly of a shoe, placed on a carrier 77. The laser apparatus 71 emits a laser beam 75 which is appropriate to generate heat for removing sole material from the sole target. Further, there is provided a scan head 72 and a mirror 73 for deflecting the laser beam 75 appropriately. The laser beam 75 is guided through a focus lens 74 and vertically down to the sole target 76, where the laser beam is swept across the sole target 76, which is mechanically fixed to the carrier such as a non-moving table 77, by means of the scan head 72 and mirror 73. A control unit 78 controls the position of the mirror 73 for deflecting and sweeping the laser beam in a way that one or more of desired openings, passages, or cavities may be generated in the sole target by removing sole material from the sole target appropriately. A laser work station following this principle is manufactured, e.g., by the company CEI Companhia de Equipamentos.
FIG. 5B shows another possible laser work station 90 following a working principle as proposed by the applicants. During operation the laser beam 95 of this work station runs with automatic variable speed in the range of 50-15000 mm/s. The laser work station comprises a laser source 91 and a control unit 92, which controls a robot 98 and the position of a mirror 93 in a scan head 94. A laser beam 95 is sent via focus lens 96 to a sole target 97, and hits the sole target in focus point F. The sole target 97 is positioned in front of the laser beam 95 by means of robot 98, which has a moveable arm 99. The arm 99 is able to position nearly all parts of the sole target 97 in the focus point F, and can make minute movements back and forth.
For example, both laser workstations use a CO2 laser manufactured by the company Synrad, which is of the Firestar series, model FSF201SB (dual tube laser). It is able to give a maximum of 700 W at wavelength 10200-1060 nm (EN 60825-1), but tests were made in the range up to 300 W. The scan heads 72 and 94 used are manufactured by the company Raylase AG. The laser can be run in either continuous wave power output mode (CW) with a lower maximum output, or in a pulsed wave power output mode (PW) with close to maximum power output. In PW mode the modulation frequency is up to 25 kHz and the duty cycle variable, but typically set to 50%. The programming language used for the laser work station 70 is Visual Basic, and after compiling the program, the software is downloaded to the laser machine. The laser work station 90 uses a programming software developed by the company Raylase AG. If images are to be engraved in a sole, different data formats can be used, e.g. the well known formats jpeg or dxf which can be loaded into the programming software of both laser work stations.
The polyurethane used in the tests below is based on polyester. Similar tests have been made with polyether based polyurethane with the same or nearly the same results. All tests were made in PW mode.
Generally, a laser beam of a laser apparatus for being used in accordance with aspects of the invention can be controlled with several parameters input to the laser apparatus, namely continuous wave (CW) mode or pulsating wave (PW) mode, power (W), speed (mm/s), number of cycles and focus control. Controlling the point of focus, i.e. of maximum power, can be made via the laser apparatus itself; the apparatus typically has a scan head with mirrors for moving the laser beam, and by adding an extra lens the point of focus can be moved along a z-axis. Alternatively, focus control can be made by moving the target into and out of focus, e.g. through use of a controllable robot arm. Both continuous wave and pulsating wave mode can be used; the pulsating wave modus mainly creating dots, whereas the CW mode is preferred for creating lines without showing the dot effect. The power of the laser is varied in the range of 5% to 100%. In the examples given below the power range was chosen up to 300 W, but higher power can also be used. The speed of the laser beam is the speed with which the beam moves across the surface of the respective part of the sole. In our experiments we worked in the range of 50 mm/s to 16000 mm/s. The number of cycles denotes how many times a predetermined route of the laser beam is repeated, or how many shots are made in the same place. For example, for making a cylindrical through-hole, opening or passage the laser beam will describe in the respective part of the sole a circle in a first cycle, then repeat the circle in a second cycle and so on until the hole, opening or passage has been created. In our experiments the number of cycles has been in the range 5 to 30. For controlling the width of a line when engraving letters or a drawing, the predetermined route of the laser beam can be offset, e.g. 0.5 mm, to one side after finishing the first series of cycles. Then a second series of cycles is executed. In this way a wider line is created.
When lasing in a respective part of the sole, however, some unwanted effects may occur. If lasing is done with too high energy, with too many cycles or too slowly, melting of the sole material in the area of lasing can occur. The result of this melting is an unwanted shining of the areas lasered, and especially the PU also sometimes gets sticky. The shining effect in letters or images can be alleviated by afterwards filling or covering the bottom of the lasered channel with paint. This enhances also the visibility of the lasered letters or image. Alternatively, the shining can be avoided by finding through experiments the best settings of speed, power and number of cycles. Another side effect is in relation to creating cylindrical through-holes or passages in the sole. The circular area next to the edge of the hole or passage where the laser beam enters shows in some situations melting effects; the sole material is in these areas slightly deformed and shiny. This is especially the case if holes with a large diameter (>5 mm) are to be made, because a high amount of energy is needed.
In the following, a number of examples and results thereof are described:

Example 1

A PU sole with a polyurethane based on polyester contains hydrolysis preventing additives calcium and magnesium in a concentration of 5% of the weight of the polyol of a tank A. The polyol contains both process additives and hydrolysis preventing additives. In a tank B the isocyanate (MDI 4.4 (Methyl Di Isocyanate)) is contained, and a mixture of A and B in the ratio of 100 to 121 is injected into a sole mould. The polyurethane has a density of 0.5 g/cm³, a shore A hardness of approximately 41, and free density rise of 300 gram/liter.
In order to engrave the letter “A” with lines five points of the A were defined, see FIG. 6 d. Left leg low is point 200, top of legs is 210, right leg low is 220, middle of left leg is point 230 and middle of right leg is point 240. These digitized points are loaded into the laser software program of the laser workstations of FIGS. 5A and 5B, and the program will look like this:
From point 200 to 210: laser on
From point 210 to 220: laser on
From point 220 to 230: laser off
From point 230 to 240: laser on

Ends

In another test, the letter “A” was then engraved through lasing into a smooth surface of the PU sole. Laser workstation of FIG. 5B was used. PW mode, 50% power, 20 cycles. After ending the first series of cycles the laser route was offset a bit to one side in order to get wider lines of the A. The result was a 2 cm high, 1.5 mm wide and about 0.2 mm deep A, see FIG. 6A. The edges of the A had an acceptable sharpness, and the bottom of the A was not shining. In order to obtain an A with deeper lines, the test was repeated but the number of cycles changed to 30.
In another test, the edge 250 was sharp and acceptable, but the bottom 251 of the channel was rough showing peeks and valleys in the surface and clear melting effects, see FIG. 6B.
In this case too much heat was generated in target area of the PU sole. In a further test an A in outline was generated, see FIG. 6C. Here, using the laser workstation of FIG. 5A, the laser beam has made channels 252 but left the interior surface of the A untouched. This A was 30 mm in height, depth into the sole 1 mm, PW mode with 30% power and speed 30 mm/s. The result was very good with clean sharp edges and a smooth bottom in the channels of the A. A repetition of the test with 100 mm/s gave a very weak A with a depth of approximately 0.1 mm. The A was nearly not visible in the sole.

Example 2

A logo “ECCO with a stripe” (FIG. 7A) was lasered into a PU sole by means of the laser workstation of FIG. 5A. Power 20%, speed 16000 mm/s, number of cycles 5. There was a melting effect in the lasered areas 400 which melting could be visually covered by using paint as described. Further, the sole showed some discoloring 410 meaning that there was created an irregular white surface layer next to the letters. The layer was to a certain extent removable just by wiping it off or using a wet towel, and was caused by smoke from the burned PU. In order to avoid this further manufacturing step during production, a fan or an exhaust device was used for removing smoke generated by the laser beam. In a second trial the logo “GORE” with an arrow was lasered in the PU sole in an outline format as shown in FIG. 7B. The power used was 100%, the speed 500 mm/s and the number of cycles 5. The result was a logo with well defined sharp edges. The channels 420 of the outline of the logo were approx. 0.8 mm wide and 0.4 mm deep.

Example 3

A lion image 430 (FIG. 7C) was created in CorelDraw™ and downloaded as a dxf-file into the laser workstation of FIG. 5A. In a first trial the power of the laser was set to 50% and the laser speed to 1227 mm/s, the number of cycles was 5. The width of the resulting line was approx. 0.5 mm. The sole was a PU sole as described. The result was a good copy of the original drawing with a depth of approx. 0.2 mm. Repeating the lasing in a second trial but with 100% power the depth became approx. 0.5 mm. In a third trial the laser speed was lowered to 500 mm/s while the power was 100%, and this gave the best result with a depth of approx 0.9 mm and a clearly visible lion. No discoloring or melting effect was observed in the PU.

Example 4

A grey outsole of styrene butadiene rubber (SBR), intended to be adhered to a polyurethane midsole and having a profiled tread, was used. The thickness of the outsole varied between five and two millimeters. A circle with a diameter of four centimeter was lasered in the tread—by the variable speed laser workstation of FIG. 5B. Laser power was 80%, number of cycles 20. The result is a circle which is nearly cut fully through the outsole, but not completely. The outsole smelled bad, but the smell disappeared after a few months. There was a white discolouring at the edge of the circle of the grey SBR outsole.

Example 5

A black latex outsole with a thickness of 2 millimeters is intended to be adhered to a PU midsole as the tread. The latex outsole was lasered by the workstation of FIG. 5B with a circle under the same conditions as in example 4. The edge was sharp and clean, but the outsole smelled bad. As with the SBR outsole of example 4 the smell disappeared after a few months.

Example 6

A sole consisting of a mixture of small pieces of cork and PU was lasered by the FIG. 5B workstation in the tread with a circle having a diameter of 4 cm. The power was 80%, the number of cycles 15. The laser beam cut 5 mm into the 10 mm thick sole. The edge of the circle had an acceptable sharpness, and there was no debris. It had a bad smell which disappeared after a few months. This type of sole is better suited for making through-holes, openings or passages than for engraving letters or images.

Example 7

The laser workstation of FIG. 5B is used. A TPU outsole was lasered with a circle of 4 cm in diameter, 15 cycles, 80% power. The thickness of TPU outsole was 2 mm, and it was nearly lasered through. Burn and melting effects visible on the edges, but the sharpness of the edge was acceptable.

Example 8

This trial concerns making a through-hole or passage in a PU sole which PU has the same characteristics as described under example 1. The approx. 12 mm thick PU sole was subjected by the laser workstation of FIG. 5A to lasing in a vertical direction of the sole, i.e. from the upper surface towards the tread. The power was 80%, the number of cycles 20 and the speed was set to 500 mm/s. A cylindrical through-hole with a diameter was created by the laser beam which lasered a circle line having a channel width of approx. 1.3 mm. The cylindrical left-over in the middle of the through-hole could afterwards be removed. The edge of the through-hole was sharp.
Further trials for making through-holes in a PU sole were made. A 1 mm hole was made in a 15 mm PU sole in the vertical direction of the sole. The through-hole had a sharp edge and there was no debris left. The entry of the hole was circular with a 1 mm diameter, whereas the exit hole was a bit smaller, approx. 0.8 mm. Thus the laser beam basically creates a conical channel or passage when creating a hole. The laser power was set to 100%, laser speed 500 mm/s and the number of cycles was 5. This size of holes is well-suited for a sole which has to have ventilating characteristics.
Several small through-holes or passages can thus be distributed across the surface of the tread of a sole or across the bottom or side surface of a midsole. Through these holes, which can number between e.g. 25 to 200, the sweat and moisture from the interior of the shoe can be guided to the exterior of the shoe, hereby improving the climate comfort of the foot.
In a further trial with the same parameters as above, but with only one cycle, the result was a hole or cavity of 1 mm diameter and 12 mm deep, i.e. not a through-hole. In an even further trial a 4 mm through-hole was made with power set to 100%, speed 50 mm/s and number of cycles 5. The through-hole showed the same conical characteristic as described above.

Example 9

A laser workstation according to FIG. 5B was used. In this test, a lateral (particularly horizontal) hole was shot into a midsole corresponding, in principle, to surrounding sole element 80 of FIG. 1 to make the lateral passages 50 by means of a laser beam instead of using pins in the mould. The midsole was subjected to a 90% power, 30 cycles trial. The diameter of the hole was 5 mm at the outside of the midsole, but narrowed in a bit inside the midsole. The depth of the passage made was 30 mm. Larger penetration depths would be possible by increasing the power or decreasing the speed.

Example 10

A laser workstation according to FIG. 5B was used. This test concerns shooting a hole or opening 55 (FIG. 1) in the side wall of a ventilating sole element formed by PU, which corresponds, in principle, to the ventilating sole element 60 of FIG. 1, while shooting through a lateral passage 50 in the midsole, which passage was previously made by pins of an aluminium mould for forming the midsole.
For example, the opening was made in the side wall of the ventilating sole element by keeping the beam of the laser in a fixed direction (i.e. no sweeping of the laser beam) and letting the robot position the target spot of the element aligned with the center of the laser lens. This means that the laser beam was not swept. Instead only the robot arm holding the sole was moved. However, there may be applications in which a mirror may be used when making such openings in an element of a sole.
In FIG. 8, as an example for illustrating principles of the invention, a schematic manufacturing environment is shown for forming openings 55 in the side wall 602 of a ventilating sole element 60. As can be seen from FIG. 8, the laser beam 95-1 will open the hole or opening in the side wall 602 because there is no beam deflection with respect to the lateral passage 50 where the laser beam is shot through. On the other hand, if the laser apparatus 91 is equipped with laser mirrors for deflecting the laser beam, a deflected laser beam such as laser beam 95-2 will not reach the bottom of the passage 50 in case the passage has a certain length as in the present application.
According to an example a number of openings can be made in a polyurethane sole. The sole material used may be Elastollan™ from manufacturer Elastogran GmbH. Elastollan has a relatively low density (0.35 g/cm³) and is often used for shoe midsoles. The following steps may be applied in various ways, in combination or individually depending on the particular implementation and needs.
(1) In a first step the sole target is placed in front of the laser by the robot. (2) In a second step the target spot on the sole or element thereof is placed orthogonally to the laser beam by the robot. (3) In a third step the laser beam hits the sole material at an angle to the sole (element) surface of approximately 90 degrees. (4) In a fourth step the focus of the laser is kept constant, i.e. unchanged. (5) In a fifth step a series of laser shots towards the target spot is performed (e.g., multiple shots in the same place). The number of cycles may be between 1 and 10 depending on the power of the laser and material and depth of entry. Duration per cycle may be approx. 1 ms.
When applied for connecting the lateral passages of the surrounding sole element to the structure or material of the ventilating sole element, the laser shots may result in a diameter of the openings in the side wall of the ventilating sole element which equals the diameter of the passages made by the pins in the surrounding sole element during injection. In order to get the desired diameter the number of cycles can be varied as can the relative position of the shots. During a shot cycle the target can be moved a few millimeters (e.g., the robot moves), and the diameter will increase. In a further step, the robot moves the sole to the next target spot, i.e. the process goes to the second step (2) above.
In relation to the ventilating sole element, the opening of the side wall of the ventilating sole element with laser leaves no debris. Everything is burned away. Hereby any clogging of the air channels caused during manufacturing of the openings is prevented. The method further has the advantage that it is very fast compared to drilling out the openings.
In the present example, the diameter of the opening 55 in the wall 602 should be a bit smaller than the diameter of the passages 50 already present in the surrounding sole element; otherwise the laser beam would aesthetically damage the visible edge of the passage.
example, the ventilating sole element is made of a polyurethane based on polyether. The laser beam was applied with 70% power, and the number of cycles was 5. A 2 mm diameter opening was made in the wall of the ventilating sole element. No damage of the walls or side of the midsole occurred.

Claims

What is claimed is:

1. A method for manufacturing at least one part of a sole assembly of a shoe comprising the steps of directing a laser beam towards the at least one part of the sole assembly comprising a polymer material and creating at least one of an opening, passage, cavity or engraved pattern in the at least one part of the sole assembly by means of the laser beam, or removing material from the at least one part of the sole assembly by means of the laser beam.

2. The method according to claim 1, wherein the at least one part of the sole assembly comprises a polymer material which is resistant to hydrolysis or contains material which is resistant to hydrolysis.

3. The method according to claim 1, wherein the at least one part of the sole assembly comprises a polyurethane material based on a mixture of an isocyanate and a polyether.

4. The method according to claim 1, wherein the at least one part of the sole assembly comprises a polyurethane material based on a mixture of an isocyanate and a polyester based polyol, wherein one or more of hydrolysis preventing additives are added to the polyol.

5. The method of claim 4, wherein one or more of the following hydrolysis preventing additives are added to the polyol: calcium and magnesium carbonate, or calcium and magnesium stearate, particularly in the range of 1% to 10% of the weight of the polyol including process additives, if any.

6. The method according to claim 1, wherein the at least one part of the sole assembly comprises a thermoplastic polyurethane, or a mixture of cork and polyurethane.

7. The method according to claim 1, comprising the step of creating at least one opening or passage by means of the laser beam such that the opening or passage is connecting an interior of the shoe with an outside of the shoe for air ventilation of the shoe.

8. The method according to claim 1, comprising the step of creating at least one opening or passage by means of the laser beam, wherein the opening or passage has a diameter in the range of 0.1 to 5 millimeters.

9. The method according to claim 8, wherein the point of laser beam focus is placed on a side wall of the at least one part of the sole assembly.

10. The method according to claim 1, further comprising the steps of

providing a ventilating sole element having a structure or material allowing for air flow through it, and

creating at least one opening in a side wall of the ventilating sole element by means of the laser beam such that the opening is enabling air ventilation from an interior of the ventilating sole element to an outside of the shoe.

11. The method according to claim 1, comprising the step of creating at least one opening or passage in an outsole, midsole or surrounding sole element of the sole assembly,

12. The method according to claim 10, further comprising the step of creating at least one opening or passage in a side wall of the ventilating sole element, which has a structure or material allowing for air flow through it and which is at least partially surrounded by at least a portion of the sole assembly with at least one passage in it, by means of the laser beam directed through the at least one passage in the portion of the sole assembly surrounding the ventilating sole element, in particular the outsole, the midsole or the surrounding sole element.

13. The method according to claim 1, wherein the at least one part of the sole assembly comprises at least one of the following materials: TPU, styrene butadien rubber, latex or cork.

14. The method according to claim 1, comprising the step of creating at least one of an opening, passage, cavity or engraved pattern in a lateral, medial, front or back side of the at least one part of the sole assembly.

15. The method according to claim 1, wherein the laser beam is controlled to generate a power output in a range between 50 W and 500 W at a speed in the range of 20 mm/s to 2000 mm/s.

16. The method according to claim 1, wherein the laser beam is applied in a laser beam cycle which repeatedly scans over a portion of the at least one part of the sole assembly, wherein the laser beam cycle is repeated within the range of 5 to 30 times.

17. The method according to claim 1, further providing a controllable robot which is adapted to place the at least one part of the sole assembly in front of the laser beam, wherein the laser beam through a series of repeated laser cycles on the at least one part of the sole assembly creates the at least one of an opening, passage, cavity or engraved pattern, or removes material from the at least one part of the sole assembly.

18. The method according to claim 17, wherein a point of focus of the laser beam is changed in steps in the following way:

a) placing the target of the at least one part of the sole assembly in a point of focus,

b) performing a first series of laser cycles which generate a channel with a first penetration depth,

c) moving by means of the robot said at least one part of the sole assembly towards the point of focus so that the bottom of the channel is placed in the focus point of the laser beam,

d) performing a second series of laser cycles which deepens the channel in the sole.

19. The method according to claim 1, wherein the at least one part of the sole assembly is formed by sole material injected onto an upper of the shoe, or is part of a pre-assembled part of the sole to be glued to an upper of the shoe.

20. The method according to claim 1, wherein a first laser workstation is used for roughing an upper of the shoe, whereafter the upper is placed in a mould and sole material is injected onto parts of the upper and hereby adhered to the upper, and whereafter the first laser workstation or a second laser workstation is used for creating the at least one of an opening, passage, cavity or engraved pattern, or removing material from the sole material.

21. Sole assembly for a shoe comprising at least one part which is manufactured from a polymer material, wherein the at least one part of the sole assembly comprises at least one of an opening, passage, cavity or engraved pattern created by means of a laser beam.

22. The sole assembly according to claim 21, wherein the at least one part of the sole assembly comprises a polymer material which is resistant to hydrolysis or contains material which is resistant to hydrolysis.

23. The sole assembly according to claim 21, wherein the at least one part of the sole assembly comprises a polyurethane material based on a mixture of an isocyanate and a polyether.

24. The sole assembly according to claim 21, wherein the at least one part of the sole assembly comprises a polyurethane material based on a mixture of an isocyanate and a polyester based polyol, wherein one or more of hydrolysis preventing additives are added to the polyol.

25. The sole assembly of claim 24, wherein one or more of the following hydrolysis preventing additives are added to the polyol: calcium and magnesium carbonate, or calcium and magnesium stearate, particularly in the range of 1% to 10% of the weight of the polyol including process additives, if any.

26. The sole assembly according to claim 21, wherein the at least one part of the sole assembly comprises a thermoplastic polyurethane, or a mixture of cork and polyurethane.