The present invention relates to a machine with a device for applying glue onto soles of footwear and to a method for applying the glue using such a machine.
In the production of footwear it is known that there exists the problem of managing to distribute suitably the glue on the soles so that it is uniformly distributed over the whole surface to be glued, while however preventing the glue from spilling out over the edge of the sole and soiling the part of the sole which will be visible after mounting on the footwear.
This problem occurs in particular in the case of soles with a raised edge or “box” soles. In fact, in the case of these soles it is required to spread the glue both on the bottom and on the inside of the raised edge with great precision in order to avoid deficient gluing or defects resulting from the spilling over of the glue onto the outer part of the sole and the footwear.
This problem is particularly important since it is becoming increasingly more common to use shoes types (i.e. sports shoes, working footwear, mountain or military boots) which have this type of sole instead of a flat sole. The edge of these soles often is not uniform and may have significant and discontinuous variations in height.
In the industrial production of footwear, the operations of distributing the glue on the bottom of the soles are performed in most cases using industrial machines or robots, generally having a tool with a rotating brush or a spray nozzle.
These machines or robots usually have a system for moving the tool in space so that it is able to follow suitable paths on the surface of the sole which is fixed inside a suitable seat in the machine. The movement system may be for example a movement system with Cartesian axes or a polar system with sufficient degrees of freedom such that it is able to follow with reasonable precision the inner surface of the sole and apply the glue thereon.
Usually, the applicator tool mounted on the application system is a glue spraying nozzle or an axially rotating brush with the glue being dispensed from the inside thereof and supplied to its front end which is in contact with the sole.
Gluing of the raised edge of the sole must in any case be performed manually also in situations where a high productivity is required since there exists no tool which is able to distribute the glue without imperfections on the raised edge. As mentioned above significant and irregular variations in height of the edge also complicate matters further.
In the case of machines with spray gluing systems the spraying nozzle makes it difficult to adjust the amount of said glue being dispensed and there is also the risk of the glue being sprayed beyond the edge of the sole. Moreover, for the gluing of soles a brush with bristles is preferred since its mechanical glue spreading action improves the final strength of the bond since it favours the penetration and contact adhesion of the glue. The result, however, is not always satisfactory, in particular in the case of soles with a particular edge, for example rounded edge, or soles with a raised edge.
In fact, a rotating brush by nature has edges which are not precise and well-defined and the glue application zone is consequently less precise and risks causing the glue to spill over the edge of the sole.
Attempts to automate the operation of distributing the glue also onto the raised edge of the soles have therefore hitherto not provided satisfactory results and the operation of distributing the glue along the edge of the sole is therefore performed mainly manually, for example using a small brush, similar to a tooth brush, with an obvious enormous increase in the amount of time and therefore labour required, in particular in the case of high production outputs (for example 1000/1200 pairs or more per day). This manual operation requires furthermore skilled operators who are sufficiently experienced in distributing glue in a precise and uniform manner.
The general object of the present invention is to overcome the drawbacks of the prior art, by providing a machine with a device for applying glue onto the soles of footwear which is able to ensure a satsifactory degree of precision during application of the glue also on soles with particular edges and in particular soles with a raised edge.
In view of this object the idea which has occurred, according to the invention, is to provide a machine for applying glue onto a sole of footwear, comprising a support for a sole, a glue dispensing device and a movement system for moving the device relative to the support under the control of a control system of the machine so as to follow, with the device, gluing paths along a sole placed on the support, characterized in that the glue dispensing device comprises a radial brush which is motorized to rotate about its central axis and is designed to pass lightly with its radial periphery along a sole to be glued placed on the support, and a dispensing unit designed to dispense glue on the periphery of the radial brush, the support for the sole being designed to fix a sole with an inner side of the sole directed towards the dispensing device.
Still in view of the aforementioned object, the idea which has also occurred, according to the invention, is to provide a method for applying glue onto a sole by means of the aforementioned machine, characterized in that the control system moves the radial brush along paths on the sole with a rotation axis of the radial brush which is kept substantially parallel tangentially to the edge of the sole on the support so as to spread the glue along this edge.
In order to illustrate more clearly the innovative principles of the present invention and its advantages compared to the prior art, examples of embodiments applying these principles will be described below with the aid of the accompanying drawings. In the drawings:
With reference to the figures,
The movement may be automated by means of a per se known computerized control system 15 (for example a suitably programmed microprocessor system).
Advantageously the movement system 13 of the machine 10 comprises a head 16 on which the device 14 is mounted and a support 17 designed to receive and fix in position, in the zone 11, the sole to be glued. As can be clearly seen in the figures, the support for the sole is designed to fix a sole with an inner side of the sole directed towards the dispensing device. “Inner side of the sole” is obviously understood as meaning the side of the sole intended to be glued to the bottom of a shoe.
The head 16 and the support 17 are movable relative to each other by means of drives which allow the glue application device 14 to follow the desired paths. The movements may be for example interpolated by the control system 15 so as to follow the desired paths, in a manner substantially known per se to the person skilled in the art.
The movement system 13 may be of the type substantially known and able to be easily imagined by the person skilled in the art and will not be described nor shown in detail here. Essentially, this movement system 13 may comprise the necessary degrees of freedom of movement in the space in order to follow the desired paths with the desired inclination of the operating end of the device 14.
For example, four or five degrees of freedom for relative positioning of the device 14 and support 17 may be advantageously provided.
As will become clear below, the movement may be performed so that the necessary degrees of freedom may be obtained with a movement of the head 16 alone, while keeping the support 17 stationary in the machine, or by means of a combination of relative movements of head 16 and support 17.
In particular, as schematically shown in
Advantageously, the movement along one of the Cartesian axes (for example the axis 18 in
In the example of embodiment, a motorized carriage 21 moves along the axis 20 and supports a track 22 which extends along the axis 19 and supports in turn a motorized carriage 23. The motorized carriage 23 has, arranged thereon, a further motorized carriage 24 for movement of the head 16 along the axis 18. In this way the controlled movement of the head along the three orthogonal Cartesian axes 18, 19 and 20 may be easily obtained.
Alternative embodiments may, however, be easily imagined by the person skilled in the art. For example, the track 22 may be designed so as to move on the carriage 21 along the axis 18 such that the head 16 is moved vertically without the need for the carriage 24.
Advantageously, the head 16 comprises further drives for performing desired inclination movements of the device 14 relative to the sole 12. In particular, the head 16 may be provided with a first motorized axis of rotation 25 arranged parallel to the axis of displacement 18 so as to allow an orientation movement of the device 14 generally in the plane of the sole (as will be explained below).
Advantageously, the head 16 will also comprise a second motorized axis of rotation 26, arranged at angle with respect to the axis 25. As may be easily imagined by the person skilled in the art, the combination of coordinated rotations of the two axes 25 and 26 thus allows inclination of the device 14 so as to orient it within space while it follows the path along the sole.
In the embodiment described here by way of example, the four axes 18, 19, 20 and 25 essentially allow positioning of the head, while the angled axis 26 allows inclination of the brush to be performed.
All the motorized movements of the machine may be controlled by the known electronic control unit 15 in which the paths to be followed may be programmed depending on the model and size of the sole being machined, as is well-known to the person skilled in the art. A suitable known man/machine interface (not shown), for example provided with keyboard and display or touch screen display) may also be provided in order to enter the path data, also by means of self-learning, start and stop the various machine operations, carry out tests and calibrations, etc., as is known to the person skilled in the art for this type of machine.
In order to fix the sole to the support 17, the support 17 may comprise suitable gripping members 27, 28 which are arranged opposite each other and are suitably shaped so as to fix between them the sole 12, gripping it between the front and rear ends (as can be seen also in
The gripping members may be advantageously two shaped jaws which are movable towards each other (manually or preferably by means of a motor or cylinder movement) so as to grip the sole between them.
The system for gripping and fixing the sole may also be different from that shown. For example, it may comprise a known suction system or other systems which ensure the grip and the stability of the sole 12 on the support 17.
Obviously, the support 17 may be shaped so as to receive soles which have a form which is not necessarily flat (for example soles also with a very high heel), as may be easily imagined by the person skilled in the art.
This device 14 comprises in an innovative manner a radial brush 30 which rotates about a motorized axis 31. Preferably, the radial brush 30 has radial bristles which are grouped together along the circumference of the brush to form groups of radial bristles arranged in several planes parallel to each other and transverse to the axis of rotation 31. For example, there may be three planes as can be clearly seen in
The radial brush 31 is designed to be driven rotationally with its periphery against the sole so as to spread glue over it, as schematically shown in the figures. The speed of rotation of the brush 30 may be for example between 50 and 150 rpm and preferably is in the region of 100 rpm. The speed may also be programmed depending on the requirements and the machining operations. If desired, the maximum speeds may be even greater than 150 rpm, for example up to 450-500 rpm.
The device 14 also comprises a dispensing unit 33 designed to dispense the glue on the periphery of the radial brush 30. As shown in
Preferably, the dispensing unit 33 comprises at its front end a small brush 34 which rests with its end against the periphery of the radial brush. In particular, the brush 34 lies along an axis 35 arranged radially with respect to the radial brush 30 so as to rest radially against the periphery of the radial brush 30.
In the centre of the brush 34 there is advantageously a nozzle 36 which is supplied by a suitable source of glue known per se (for example comprising a duct for receiving glue under pressure from a supply tank). The glue may be of any type considered suitable. For example, it may be a solvent-based glue.
Essentially, the nozzle 36 dispenses the glue between the bristles of the end brush 34 and the brush 34 in turn spreads this glue on the tips of and between the bristles of the radial brush 30.
The brush 34 is advantageously motorized so as to rotate about its axis 35.
This improves the uniform dispensing of the glue on the radial brush 30.
The rotation of the radial brush about the axis 31 allows the glue to be spread uniformly over the entire periphery of the radial brush 30 and the consequent uniform transfer of the glue onto the sole.
The combined rotation of the end brush 34 and the radial brush 30 ensures an even more uniform glue spreading action.
Advantageously, during operation of the machine the radial brush 30 will be brought into contact with the sole with an orientation such that the radial brush 30 rotates with a direction of rotation such as pass lightly along the sole towards the free end of the edge of the sole. For example, the rotation of the brush will be anti-clockwise in
This has been found to be advantageous for a precise application as far as the end of the sole edge, avoiding spreading of glue over the sole part which will be visible after it has been mounted on the footwear.
An applicator device such as that described according to the invention has been found to be particularly advantageous with these types of sole since any spreading of glue beyond the top end of the sole edge is avoided, while the glue is applied over the whole inner surface of the raised edge and over the zone of the bottom of the sole close to this edge.
If desired, the movement of the radial brush may naturally continue also towards the centre of the sole such as to glue also more central portions of the sole.
Advantageously, the applicator device 14 may also comprise a protection 38 (for example formed with a metal or plastic strip) arranged along a portion of the periphery of the radial brush 30 so as to prevent the rotation of the brush from causing, owing to the centrifugal force, glue to be propelled in the direction opposite to the edge of the sole, thus soiling zones of the sole which are not intended to be glued. The protection may, if necessary, be adjustable position wise.
Adjustment of the position of the protection 38 may also allow the point of “attack and contact” of the brush 30 on the sole to be modified.
A motor 40 may cause rotation of the head about the axis 25, while a motor 41 may cause rotation of the head about the angled axis 26.
A motor 42 may cause rotation of the axial brush 33 which contains advantageously the glue dispending nozzle 36.
Finally a motor 43 may cause rotation of the radial brush 30 about the axis 31. The motor 43 may be connected to the brush 30 by means of a suitable drive 44, for example a double right-angled transmission, so as to reduce the dimensions of the head in the region of the brush 30 and allow the brush to be easily moved towards the sole to be glued.
The device 10 comprises an inlet duct 45 for the glue 45 which must be dispensed and must reach the nozzle 36. Advantageously, the glue passes from the inlet duct 45 to the nozzle 36 via a supply duct 36 which preferably houses inside it a stem 47 which also allows adjustment of the glue flow, for example by means of an adjustable axial movement thereof, allowing opening or closing of the aperture for through-flow of the glue towards the outlet of the nozzle 36. A suitable known rotatable hydraulic joint 48 may be provided in order to allow transfer of the glue from the inlet 45 to the duct 46 which rotates together with the brush 33.
Owing to the device according to the invention, it has been found that the glue may be spread rapidly, with great precision and without spillage on soles formed with a raised edge, be it with a constant or variable height, advantageously using automatic machines.
The machine according to the invention has also been found to be particularly suitable for gluing soles without a raised edge, being able to glue perfectly and rapidly the edge of the sole without spillage of glue, whatever the form of the edge.
For example,
A further advantage of the applicator device provided according to the invention is that of being able to apply adequately the glue onto the inner part of soles of the internally ribbed type, as shown in the cross-section of
In the case of these soles, spreading of the glue into the open chambers between the ribs may be damaging because, in addition to wastage of glue, gas is formed inside the chambers during setting of the glue once the sole has been applied to the bottom of the shoe. This gas remains trapped between the sole and the bottom of the shoe and may result in weakening of the glued joint and other known problems.
The known glue spreading systems are unable, however, to prevent the glue entering into the chambers between the ribs.
The device according to the invention allows, instead, the rotating brush to spread the glue substantially only on the ends of the ribs, which will come into contact with the bottom of the shoe, without any glue spreading into the chambers between the ribs, as can be clearly seen from
The protection 38 also helps protect the point of contact between the bristles of the brush 30 and the ends of the ribs so as to prevent the transfer of the glue into the zones close to the surface to be glued.
The movement of the rotating brush shown in
If need be, the dispensing unit 33 may in any case spread the glue also on other points of the surface of the sole as well as in the zone close to the edge. For example, the dispensing unit (in particular with the axial brush) may be used to spread the glue over the entire surface of a sole to be glued.
This cleaning device 52 comprises a tank 53 containing two cleaning brushes 54, 55 arranged with their bristles facing and spaced from each other. The cleaning brushes 54 and 55 are advantageously cylindrical and are supported by a coaxial shaft 56 controllably rotated by a motor 57. The tank contains advantageously a cleaning liquid which is suitable for the glue used and within which the cleaning brushes are partially immersed. For example, this liquid may be a suitable solvent, such as acetone, for solvent-based glues or also water for water-based glues, etc.
Periodically the machine may move the dispensing unit 33 (and in particular the axial brush 34) and/or the rotating brush 30 into the space between the cleaning brushes. This space is such that the bristles of the cleaning brushes interact for example with the bristles of the axial brush 34 and/or with the bristles of the rotating brush 30, as is clear from
In this way, the cleaning brushes may remove the excess and/or partially dried glue. The motor 57 may periodically cause rotation of the cleaning brushes so as, in turn, to clean the glue from them by immersing them in the liquid inside the tank. The liquid which remains on the cleaning brushes may also ensure better cleaning of the axial brush 34 and the rotating brush 30 which are also rotationally operated during the cleaning cycle.
It is also possible to provide scraper elements 58, 59 (for example two elongated elements such as a pin or blade) which are inserted radially into the brushes 54, 55 so as to slide along their bristles and help remove the glue from the cleaning brushes during rotation of the brushes.
At this point it is clear how the objects of the invention are achieved.
With a machine having the glue application device according to the invention it is possible to perform satisfactory gluing operations on soles which also have a very high raised edge; soles with a varying height along the edge (without having to vary dynamically and precisely the height of the dispensing head since small variations in height of the edge are compensated for by the flexibility of the bristles of the radial brush); soles with internal ribs; soles with lined edges; flat soles; welted soles; etc.
The direction of rotation of the radial brush may also be easily reversed (also by merely rotating through 180 degrees the plane of the radial brush) if it is required to apply glue onto particular types of edges (for example edges which are not raised, but have deep folds on the sole part to be glued).
Alternatively or in addition, it is also possible to reverse rapidly the rotation of the brush by inverting the direction of rotation of the motor 43, from anti-clockwise to clockwise and vice versa, also dynamically during formation of the profile.
Obviously the above description of embodiments applying the innovative principles of the present invention is provided by way of example of these innovative principles and must therefore not be regarded as limiting the scope of the rights claimed herein.
For example, the movement structure of the head and the structure of the head itself may be different from that shown for moving the applicator device within space. For example, a machine provided with an anthropomorphic arm which terminates in the applicator device may be used. The unit for dispensing glue onto the radial brush may also be different from that shown. For example, it is possible to provide a gluing roller, instead of the axial brush, or a dispensing nozzle, for example of the spray type, which deposits the glue onto the radial brush.
During the specific implementation of the characteristics of the present invention other known footwear processing systems may be incorporated in the machine. For example, the machine may be a machine combined with a station for gluing and/or roughing also the bottom of a shoe.
Number | Date | Country | Kind |
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102018000008323 | Sep 2018 | IT | national |
This application claims priority to Italian Application No. 102018000008323, filed Sep. 4, 2018, the teachings of which are incorporated herein by reference.