|
(11) | EP 1 252 833 A1 |
| (12) | EUROPEAN PATENT APPLICATION |
|
|
|
|
||||||||||||||||||||
| (54) | Device for spreading adhesives on shoe soles |
| (57) A device for spreading an adhesive substance on shoe soles, particularly box-type
soles - of the type in which said device is moved forward along the outer periphery
of the sole by way of an automatic system operating on the basis of previously memorised
information concerning the configuration of the sole peripheral edge - comprises a
flexible element (4) provided with bristles (5), formed as a closed ring and rotating
about at least two parallel rotation axes, in a direction such as to bring said bristles
(5) in contact first with a peripheral band of the bottom part of the sole (S) and
then with the inner part of said rim (M). According to a preferred embodiment, there
are two of said rotation axes, and said closed ring has an oval shape with the major
axis parallel to said rim (M) of the sole (S). |
[0001] The present invention concerns a device for spreading an adhesive substance on shoe soles and, in particular, on the so-called box-type soles, in which the outer edge or rim of the sole extends upwards, covering the vamp to an extent varying between a few millimeters and various centimeters. Moreover, said rim may have a regular shape and thus a substantially constant height throughout the perimeter of the sole, or else it may be variably shaped in correspondence of the different sole portions.
[0002] As known to the experts in the field, in the present footwear industry shoes with box-type soles have had an enormous development, particularly in the sector of sports shoes. In fact, in such shoes, the rim of the sole extends upwards, covering the vamp with even variably shaped patterns, so as to give the shoe special aesthetic features and characteristics of stoutness, foot protection and so on.
[0003] The operation for spreading the adhesive substance on this type of soles, in view of the subsequent operation in which the sole is stuck onto the vamp, can be correctly carried out up-to-date only by hand. In fact, the automatic devices for spreading the adhesive substance, used now-a-days for the conventional type soles, cannot be adopted on the box-type soles without causing considerable inconveniences which have positively precluded their application.
[0004] There are substantially two automatic systems for spreading the adhesive substance on shoe soles, known up-to-date in technique, and precisely the spray system and the brush system. Such systems, and the respective technical limits which prevent a satisfactory use thereof in the case of box-type soles, will now be briefly described with reference to figures 1 to 4 of the accompanying drawings.
[0005] A first system - of which a plan view is shown in fig. 1 and a section view in fig. 2 - is based on the use of a spray gun which spreads a finely powdered jet of adhesive substance. The nozzle 1 of the spray gun is moved forward along the rim of the sole S by means of a programmable control device, so that the jet 2 of adhesive substance hits the peripheral portion of the sole S which has to be stuck onto the vamp. This system for spreading the adhesive allows a fast application, but it has the essential drawback of soiling the sole portions close to that having to be covered with the adhesive substance, since it is normally by no means possible to control the spray of liquid vaporized from a spray gun to such a perfect extent as to prevent occasional side splashes spurting out of the main cone of the jet. All the more does this difficulty arise when the liquid being sprayed is an adhesive substance, the high viscosity of which is more likely to cause frequent splashes of said liquid beyond the main conical jet.
[0006] A first drawback of said spray system - when adopted for spreading the adhesive substance on the rim of box-type soles - hence lies in the fact that it would be practically impossible to avoid soiling with adhesive the top part of the rim M while the nozzle 1 is moving forward. Furthermore, since the rim M does not often have a stiffness such as to always keep a vertical and straightened position, but it sometimes tends to deform by partially bending over, it could also happen that, as the nozzle 1 is moving forward, it is the external part of the rim M which gets undesirably covered with adhesive, instead of the inner part thereof.
[0007] To overcome this drawback, or at least reduce its weight, it has been thought to give more inclination to the nozzle 1, so that its axis may be horizontal or almost horizontal, and the jet 2 may hit perpendicularly the inner part of the rim M thereby reducing the soiling of its top part. Nonetheless, due to the mechanical bulk of the spray gun and to the reduced spaces available inside the sole, such a solution can be practically adopted only for soles of larger dimensions, whereby it has no interest from the commercial point of view.
[0008] A second drawback in the use of a spray gun for spreading the adhesive substance lies moreover in the fact that it requires the setup of an automatic system to read and memorize the shape of the sole rim, said system then allowing to guide with precision the gun nozzle 1 while spreading the adhesive. Such a system is however complicated and difficult to realize. In fact, on one hand, it should be considered that the soles, being hot-moulded in a plastic material, each undergo a different shrinkage by cooling; consequently, their final dimensions are not exactly coinciding, whereby it would be necessary to provide for a reading system apt to detect each single sole, and not merely each sole model as it normally happens in the case of footwear. On the other hand, the sole itself has a low mechanical rigidity and is easily subject to distortions or bendings, particularly in correspondence of the rim of box-type soles, whereby the automatic reading of its profile appears to be very complicated also for this reason,
[0009] A third problem is determined by the limited spraying width of the jet of adhesive substance apt to be obtained with a spray gun. In fact, in order to be able to obtain the best possible control on the precision and definition of the jet, its diameter does not normally exceed 20-30 mm. It is thus evident that, when the rim of the box-type sole exceeds this dimension - as it easily occurs in sports shoes, wherein the rim can even reach in some points a height of 100 mm - it is indispensable to program multiple passages of the spray gun with an obvious lengthening of the working times.
[0010] A last drawback being met when the spray gun has to follow a profile of variable height - as is actually often the case of shoes with a box-type sole, whose rim is far higher in the rear part than in the front part of the shoe - is finally determined by the fact that the automatic programming of the path of the nozzle 1 is made by referring to the position of the tip of said nozzle. However, when this latter moves at a certain speed along its trajectory, there is a time lag between the moment in which the adhesive substance is sprayed from the nozzle and the moment in which said substance reaches the rim of the sole, whereby there is a certain mismatching in respect of the position in which the adhesive is applied.
[0011] Said mismatching is evidently not important when the rim of the sole has a constant height, but it can instead determine a lack or excess of adhesive substance when said rim is of variable height whereby the jet of adhesive, foreseen to cover a portion of said rim of specific height, is instead applied in an offset position in which the rim is higher or lower and will thus be insufficiently or exceedingly covered with adhesive substance. To overcome this drawback, it would hence be necessary to introduce a correction factor in programming the forward movement of the nozzle 1, and the correction would obviously depend on the - variable - nozzle moving speed along the sole and would thus be very difficult to obtain and control.
[0012] A second known system - of which a plan view is shown in fig. 3 and a section view in fig. 4 - is to apply the adhesive substance onto the sole by means of a brush. According to this system, a tool with brush 3, rotating about its own axis, is shifted by a suitable automatic control device along the rim of the sole. The brush 3 has a special cylindrical or frustoconical configuration, with an empty middle portion so that the adhesive substance, fed into the brush in correspondence of said empty portion, is spread onto the bristles by rotation and then applied on the sole by said bristles.
[0013] In this type of known systems, adopted to apply the adhesive substance on the conventional non box-type soles, the brush axis is vertical. It is however evident that such an arrangement of the brush 3 allows to apply the adhesive also on box-type soles, but only in the case in which the rim M of the sole is particularly low, i.e. a few millimetres, so as to be reached by the lateral portion of the brush 3. In all the other cases, namely in the greatest majority of the present box-type soles, the brush 3 would have to be positioned, as well as along a vertical axis, also along a horizontal axis, so as to be able to apply the adhesive substance also onto a higher rim M.
[0014] A system of this type has exactly the same drawbacks already cited heretofore for the spray-gun system, particularly for what concerns: the complexity and bulk of the mechanical structure of an operating system allowing to work both with a vertical and with a horizontal axis; the limited size of the brush, which cannot exceed a maximum diameter of 20-30 mm, so as to reach also the angle portions of the sole, and thus the need to pass the brush several times in order to be able to cover particularly high portions of its rim (as well as the passage of the brush positioned along a vertical axis, to cover with adhesive the bottom part of the sole); and, finally, the difficulty to realise a satisfactory automatic reading of the path having to be followed on the sole.
[0015] Moreover, the brush system to apply the adhesive substance, though it does not obviously involve the problem of splashes beyond the area to be covered with adhesive - characteristic of the spray system - involves however another drawback having fully similar consequences; in fact, when the brush is working along a horizontal axis, its rotary motion determines a heaping of adhesive substance onto the top part of the sole rim, which ends up by unacceptably soiling the same.
[0016] Thus, for the reasons explained in detail heretofore, no satisfactory automatic system has been supplied up-to-date to allow spreading an adhesive substance onto the rim of box-type soles; this operation hence continues to be carried out manually, by skilled workmen, with consequent high production costs.
[0017] The object of the present invention is to thus supply a system for spreading an adhesive substance on box-type shoe soles, which allows to automatize this operation without being faced with the drawbacks met in the known systems examined heretofore.
[0018] In particular, a main object of the present invention is to supply a system for spreading an adhesive substance which allows, with a single operation, to cover with a uniform layer of adhesive substance a peripheral band of the bottom part of the sole as well as its upwardly extending rim, while avoiding to soil with adhesive the top part or the external part of said rim.
[0019] Another important object of the present invention is to supply a system for spreading an adhesive substance which does not require a previous reading to memorise the shape of the rim, but which allows a complete and uniform spreading of adhesive on rims of any height and configuration, simply on the basis of the path data concerning the plan shape of the sole.
[0020] According to the present invention, said objects are reached by means of a device for spreading an adhesive substance on shoe soles, particularly box-type soles, of the type in which said device is moved forward along the outer periphery of the sole by way of an automatic system operating on the basis of previously memorised information concerning the configuration of the sole peripheral edge, characterised in that said device for spreading the adhesive substance consists of a flexible element provided with bristles, formed as a closed ring and rotating about at least two parallel rotation axes, in a direction such as to bring said bristles in contact first with a peripheral band of the sole bottom part, and then with the inner part of the sole rim.
[0021] Other characteristics and advantages of the device according to the present invention will anyhow result more evident from the following detailed description of a schematic embodiment thereof, given with reference to the accompanying drawings, in which:
Fig. 1 is a plan view of a box-type shoe sole, on which the adhesive substance is applied with a known spray-gun system;
Fig. 2 is a section view along the line II-II of fig. 1;
Fig. 3 is a plan view of a box-type shoe sole, on which the adhesive substance is applied with a known system comprising a tool with a rotary brush;
Fig. 4 is a section view along the line IV-IV of fig. 3;
Fig. 5 is a plan view of a box-type shoe sole, on which the adhesive substance is applied with the spreading device according to the present invention;
Fig. 6 is a section view along the line VI-VI of fig. 5; and
Fig. 7 is a section view, similar to that of fig. 6, in which the device for - spreading the adhesive substance, according to the present invention, is in a working position.
[0022] The known type systems for spreading an adhesive substance on shoe soles, shown in figs. 1 to 4, have already been described in detail in the introductory part of the present description and will thus not be further expounded herein. However, to make the drawings clearer, it is merely pointed out, in addition to what has already been said, that said figures illustrate only the final portion of the working tool, leaving out the entire operating system - well known per se - apt to move said tool along the preset path, namely along the peripheral edge of the sole (said path being diagrammatically and partially illustrated on the drawings by a continuous line with arrows).
[0023] The system according to the present invention, for spreading an adhesive substance on shoe soles - particularly box-type soles - adopts a spreading device of totally new conception, whose structure can be seen at once on examining figs. 6 and 7. Said device comprises a flexible element 4, formed as a closed ring and outwardly covered with bristles 5, mounted on a pair of pulleys 6, the axes of which are mutually parallel and - in the embodiment illustrated - parallel to the bottom of the sole S.
[0024] Obviously the pulleys 6 are mounted onto a support (not shown) fixed on the movable arm of an automatic control system, fully similar to those used in the known systems described heretofore. One of the two pulleys 6 is then connected to a motion source, so as to impart a rotation on the flexible element 4 in the direction of the arrow F.
[0025] The spreading device according to the present invention is very simple to use and, at the same time, most efficient. After having moved the flexible element 4 into the position shown in fig. 7, in which the bristles 5 are in contact with a peripheral band of the sole S as well as with the rim M, said element 4 is caused to rotate while the adhesive substance is fed to the bristles 5 in any point of the flexible element 4, but preferably in correspondence of its upper portion which is easier to reach. During the rotational movement of the flexible element 4, the bristles 5 come first in contact with a peripheral band of the bottom part of the sole S, and then with the rim M, covering both areas with a layer of adhesive substance, in the wanted manner. Considering the extension in height of the flexible element 4, which can be varied at will by simply varying the distance h between the axes of the pulleys 6, the inner part of the rim M can be covered over its full extension, independently from whether it is higher or lower and without requiring to previously detect and memorise the particular shape of the rim itself. Moreover, by choosing pulleys 6 having a suitably small diameter and by making the best use of the natural flexibility of the bristles 5, it is finally possible to obtain a fully homogeneous spreading of the adhesive substance also in the angle portion A of the sole S, namely in correspondence of the junction line between the bottom of the sole S and the lateral edge M.
[0026] On leaving the rim M, the bristles 5 straighten up, thereby recovering any excess of adhesive substance and thus positively avoiding to soil the top portion of said rim. Thanks to the particular configuration of the flexible element 4, it is finally evident that, should some portions of the rim M be partially bent or flabby, they would be gradually straightened up by the action of the bristles 5 of the vertical upwardly extending branch of said element 4, while the element is moving forward along its working path.
[0027] According to the invention, there are no particular restrictions for what concerns the structure of the flexible element 4. For example, said element may indifferently consist of a strip of textile, rubbery or metallic material, into which are buried the bristles and the inner part of which can be either smooth or toothed, or of a metallic chain, to each link of which there are fixed single bundles of bristles, or it may even involve other solutions of easy and economic construction; the only important feature is that the flexibility of said element 4 should be sufficient to allow it to follow the wanted path around pulleys 6 of small diameter, for example a diameter between 5 and 20 mm. By the term "pulleys" is meant any element, smooth or toothed according to the type of the flexible element, apt to permit the rotation of the flexible element about a predetermined axis; it may thus consist of rollers, toothed wheels, pinions, bushings, and other similar devices.
[0028] Moreover, according to the invention, there are no restrictions as to the kind of path which the flexible element 4 has to follow around the pulleys 6, said path being obviously determined by the number of pulleys and by the lie of the respective axes. A solution, preferred for its simplicity and economy, is that illustrated in the drawings, in which there are only two axes, mutually parallel and parallel to the bottom of the sole S.
[0029] It is however possible to provide for a larger number of axes, and thus of pulleys or other devices to support and move the flexible element 4, without thereby departing from the scope of the present invention. For example, a third pulley can be positioned at the same height as the lower pulley illustrated in figs. 6 and 7, and more inwardly than the same in respect of the sole edge; in this case, the flexible element 4 will be arranged along a right-angled triangular path having a horizontal arm of further length, useful when wishing to increase the width of the peripheral band of the sole bottom having to be covered with adhesive substance. Even the inclination of the axes in respect of the plane of the sole (normally the horizontal plane) can be varied to some extent, in the event that special conditions of mechanical assembly of the pulleys 6 or of positioning of the bristles 5 should make it necessary or appropriate, without thereby departing from the scope of the present invention.
[0030] The inclination of the transversal axis a of the flexible element 4, in respect of the rim of the sole, can instead be varied to a much further extent. According to a basic embodiment of the invention, said inclination is variable along the path so that the axis a is constantly perpendicular to a line tangent to the sole edge at the point of contact thereof with the working tool. In the case of small soles, or having a very closed angle portion A, it can instead be appropriate for said inclination to form an angle even far smaller than 90° - for instance between 5° and 90° - so as to facilitate the insertion of the bristles into the angle portion A of the sole. Preferably, the angle from 5° to 90° is formed in the forward moving direction of the working tool, so that the bristles 5 must never work with their tip pointing against the rim M of the sole. In order to obtain special results in the spreading of the adhesive substance, or to overcome particular problems in the soles having to be stuck to the vamp, it will finally be possible to also vary to a wide extent the direction of insertion of the bristles 5 into the flexible element 4, in respect of the substantially perpendicular direction illustrated on the drawings.
[0031] From the above description it clearly results how the present invention has fully reached the intended objects. The spreading device according to the present invention allows in fact to obtain, with a single passage, a perfect and homogeneous distribution of the adhesive substance over the whole area meant to be treated - consisting of a peripheral band of the shoe sole and of the upwardly extending rim thereof - without creating any problems of burrs or splashes of adhesive substance beyond said area. Moreover, to spread the adhesive substance onto the upwardly extending rim it is not necessary to be previously acquainted with the height or configuration of said rim along the sole path, whereby the step to detect and memorise such information is quite needless. Finally, the spreading device according to the present invention performs an action of support and straightening of the sole rim when this latter, due to its height and flexibility, turns out not to be perfectly straightened when starting the operation for spreading the adhesive substance.
1. Device for spreading an adhesive substance on shoe soles, particularly box-type soles,
of the type in which said device is moved forward along the outer periphery of the
sole by way of an automatic system operating on the basis of previously memorised
information concerning the configuration of the sole peripheral edge, characterised in that said device for spreading the adhesive substance consists of a flexible element (4)
provided with bristles (5), formed as a closed ring and rotating about at least two
parallel rotation axes, in a direction such as to bring said bristles (5) in contact
first with a peripheral band (A) of the bottom part of the sole (S) and then with
the inner part of the sole rim (M).
2. Device for spreading an adhesive substance as in claim 1), wherein there are two of
said rotation axes, and said closed ring has an oval shape with the major axis parallel
to said rim (M) of the sole (S).
3. Device for spreading an adhesive substance as in claim 2), wherein said rotation axes
are parallel to the plane of the sole (S).
4. Device for spreading an adhesive substance as in claim 2), wherein the minor axis
of said closed ring is perpendicular to a line tangent to the edge of the sole (S)
at the point of contact thereof with said bristles (5).
5. Device for spreading an adhesive substance as in claim 2), wherein the minor axis
of said closed ring forms an angle of between 5° and 90° with a line tangent to the
edge of the sole (S) at the point of contact thereof with said bristles (5).
6. Device for spreading an adhesive substance as in claim 1), wherein said flexible element
(4) consists of a strap of textile, plastic or metallic material, incorporating said
bristles (5).
7. Device for spreading an adhesive substance as in claim 1), wherein said flexible element
(4) is a metallic chain, to each link of which there are fixed bundles of bristles
(5).
8. Device for spreading an adhesive substance as in claim 1), wherein said rotation axes
consist of two pulleys (6), at least one of which is a driving pulley.
9. Device for spreading an adhesive substance as in claim 1), wherein there are three
of said rotation axes, and said closed ring is shaped as a right-angled triangle,
the perpendicular sides of which are respectively parallel to the bottom of the sole
(S) and to its rim (M).