WO2005094623A1

WO2005094623A1 - A method and device for inspecting the interior of a footwear

Info

Publication number: WO2005094623A1
Application number: PCT/IB2005/000767
Authority: WO
Inventors: Rosetta Lombardo
Original assignee: Elettrotecnica B.C. S.P.A.
Priority date: 2004-03-30
Filing date: 2005-03-24
Publication date: 2005-10-13
Also published as: BRPI0508198A; CN1937932A; ITMI20040620A1; EP1729606A1

Abstract

A method for inspecting the inside of a shoe, comprising the following steps: a. arranging at least one inflatable body within the shoe (1,4,101a,101b,101c,104); b. inflating, by means of a controlled amount of fluid, said inflatable body within the shoe (9,10) until the inflatable body, or a part thereof, is substantially rested on at least a portion of an inner wall of the shoe; c. after inflation, measuring and/or evaluating the internal pressure of the inflatable body and/or the force applied by said portion of an inner wall of the shoe against said inflatable body, or vice versa.

Description

"A method and device for inspecting the interior of a footwear" ******

FIELD OF THE INVENTION

The present invention relates to a method for inspecting the inside of a shoe (or a footwear) and a device for implementing the same method. PRIOR ART

In the shoe manufacture field, it is known to manufacture a shoe (i.e. a footwear), such as a shoe, a boot, a slipper, etc., by the mutual and subsequent assembly of its various components, such as the upper (or vamp), reinforcements, arch support, sole, heel and footstraps (or insole).

Particularly, according to a very simplified procedure, this assembly is carried out using a support last, which by reproducing a user's foot allows to assemble the various parts before they are definitely fixed to each other. Thereby, the upper is first temporarily fastened to the support, then the footstraps is usually removably fixed to the last, and then the arch support is fixed to the upper, and the sole to the arch support. These operations of fixing the last to the support, or optionally fixing the various parts of the shoe to each other in a non-definitive manner are usually carried out by means of mechanical clamping means, which are thin pointed in order to penetrate the various parts of the shoe; normally, they are nails, brads, clips, fasteners, hobnails or the like, either made of plastic or metal. These mechanical clamping elements are usually removed prior to the soling, and however prior to the final finishing of the shoe.

At the end of said finishing operations, a quality check on the shoe is normally carried out, which also comprises the inspection of the inside of the shoe, which may be visual, tactile and/or at least partially carried out by a detection device.

This inspection of the inside of the shoe has the double task of checking for any mechanical clamping elements that may be unduly present and may have escaped removal, or other contusive elements, and checking the geometrical conditions, i.e. the shape, the mutual arrangement and position of the various parts inside the shoe, such as the upper, reinforcements and footstraps defining the "instep" (or "fitting") of the shoe, i.e. the comfort of use of the same. As regards to the inspection of the shape, position and mutual arrangement of the upper, reinforcements, footstraps and the other inner parts of the shoe, it is a common practice to resort to a skilled operator, who is capable of identifying any misshapes or assembly errors according to his tactile sensations by putting his hand or foot inside the shoe. To these necessary tactile inspections aiming at measuring the instep in terms of quality, there can be associated quantitative measurements of the shoe inner geometry that are obtained by means of the so-called "podometer", a tool suitable to measure the width of the instep girth within the shoe, as well as by means of a measuring tape. The inspection of the inner geometrical conditions of the shoe is particularly important while testing the prototypes, which operation precedes the mass production of the shoes. In fact, thanks to the prior inspection of the inner geometry of a shoe prototype all those variations to the support last, upper, reinforcements, arch support, sole, heel and footstraps defining an optimum "instep" (or "fitting") of the shoe can be carried out.

While carrying out said tactile inspection, the operator can also perceive the undue presence of any mechanical clamping elements, but he is subjected to the hazard of being pricked and lacerated. To this purpose, several techniques of automated inspection of the inside of a shoe have been developed aiming at identifying mechanical clamping elements which may have escaped removal, before the subsequent tactile inspection step. Patent GB 0.717.487 in the name of BRITISH UNITED SHOE MACHINERY COMPANY, LTD., as well as patent US 2.385.271 in the name of HILTON, teaches to use a metal detector, either of type in which variations in an electro-magnetic field (EMF) or variations in an electric current circulating in a suitable circuit are detected, in order to identify temporary clamping elements that may be present inside the shoe. This solution, though being automated, cannot be used in the case where the mechanical clamping elements are made of plastic and is also poorly reliable in the event that the shoe is provided with decorative or structural accessories made of metal, such as buckles, rings or eyelets.

In the latter case, in fact, the metal detector readings would be wrong due to the presence of these metal objects, and therefore they would be substantially unusable for the purpose of identifying the presence of metal clamping elements. The patent US 1.707.989 in the name of MOLYNEUX describes a device for identifying and removing hobnails in a shoe, which provides optical means facilitating the visual inspection of the inside of the shoe by an operator. Particularly, the MOLYNEUX device provides the use of a light source and a mirror that are arranged such as to be inserted within the shoe for an operator to carry out a visual inspection of the interior of the shoe in an easy manner.

While being suitable to identify the presence of any hobnail that can be also made of plastic material, the MOLYNEUX device proves to be poorly effective, since it relies on an operator's skill to identify these hobnails, and is also complicated in terms of structure and use. Finally, devices for identifying mechanical clamping elements within a shoe are known which are based on inspections of the shoe by means of X-rays, or other high penetration radiations. Besides being poorly effective in identifying clamping elements made from plastic material or detecting metal clamping elements in the presence of other metal accessories, these devices are also very expensive and require to be used by skilled operators, because their operation is complicated. An object of the present invention is to provide a method and a device for inspecting the inside of a shoe that does not suffer from the prior art drawbacks such as stated above.

Another object of the present invention is to provide a method and device for inspecting the inside of a shoe which allows to carry out an accurate and reliable detection of any mechanical clamping elements, either made from metal or plastic, or other contusive elements that may be present within the shoe, and either alternatively or simultaneously, allows to identify the geometrical conditions of the different inner parts of the shoe. Another object of the present invention is to provide a device for inspecting the inside of a shoe which is structurally non-complicated and easy to use.

A further object of the present invention is to provide a method for inspecting the inside of a shoe that is reliable and easily feasible and does not provide any tactile inspection by an operator. SUMMARY OF THE INVENTION

These and other objects are achieved by the method for inspecting the inside of a shoe according to the first independent claim and the subsequent dependent claims and the device for inspecting the inside of a shoe according to the sixteenth independent claim and the subsequent claims depending thereon.

The method for inspecting the inside of a shoe, according to the present invention, comprises the following steps: a. arranging at least one inflatable body within the shoe; b. inflating, by means of a controlled amount of fluid, said inflatable body within the shoe until the inflatable body, or a part thereof, is substantially rested on at least a portion of an inner wall of the shoe. c. after inflation, measuring and/or evaluating the internal pressure of the inflatable body and/or the force applied by said portion of an inner wall of the shoe against said inflatable body, or vice versa.

It should be understood from the detailed description below that any anomalies within the shoe, such as the presence of mechanical clamping elements or wrong arrangements or shapes of the different parts of the shoe can be identified by measuring the internal pressure, and/or the force applied by the inner wall/s of the shoe against the inflatable body, or vice versa, possibly by carrying out a comparison with the expected pressure and/or force values. It should be observed that with "inflatable body" is meant herein and below a generally closed body, except for at least one inlet/outlet nozzle for a fluid, which is provided with at least one membrane, either non-elastic or elastic, being capable of changing its spatial layout, and/or capable of being elastically deformed when a fluid, either a liquid or gas, being fed within the body tends to occupy a greater volume than that available when the membrane is in its starting condition, or non-deformed condition. This inflatable body, according to the above meaning, can then comprise, for example, only elastically qeformable walls, and be thus similar to a latex balloon, or comprise non-elαsticαlly deformαble walls, for example from a folded condition to a stretched condition and vice versa, or still comprise one or more completely non-deformable walls that are fastened to at least one elastically or non-elastically deformable membrane, or any suitable combination of the above walls. With the term "fluid" is meant herein to designate not only those materials in the liquid or gaseous state, but also those materials with a fluidic behaviour, such as foams or powders dispersed in a fluid bed. , According to a preferred aspect of the present invention, the inflatable body is at least partially made of a material having a low tear strength, such as nylon, polyvinylchloride (PVC) or polyethylene, such that when following inflation this tearable part comes in contact with one or more inner walls of the shoe, the mechanical clamping elements, or other contusive elements that may be present can cause the tearing of the inflatable body and a sudden pressure drop within the same. In this case, the method of the present invention provides that the integrity of the inflatable body can be checked for the presence of these clamping elements or other contusive elements. According to another aspect of the present invention, the method provides that the measurement of the pressure, or force being applied against the inflated body, or by the inflated body, is carried out locally, such as to identify any undue gradients of pressure, or force, which may be present within the inflatable body, after it has been inflated. These gradients, when they do not fall within a range of expected values, may indicate the presence of misshaping, wrong mutual arrangements or positions of the various parts making up the inside of the shoe. According to a preferred aspect of the method according to the present invention, this inflatable body can advantageously consist of a number of fluidically separated and hence individually inflatable compartments, each being provided with a sensor for detecting the pressure or force being applied by the external environment or by the inflatable body on the external environment. By this configuration the inflatable body can closely match the shape of the inner region of the shoe to be inspected.

In a particular embodiment of the method according to the present invention, the application of the method is repeated several times during the various steps of manufacturing a shoe, and particularly the method is carried out both before and after the finishing of the shoe. This allows one to obtain a very reliable detection of any contusive body or wrong geometrical conditions of the various parts within a shoe. According to a further aspect of the present invention, there is provided a device comprising at least one inflatable body and a device for inflating the inflatable body, by means of a predetermined fluid. The device also comprises means for detecting the internal pressure of said inflatable body after inflation and/or the force applied by the external environment against said inflatable body, when inflated, or vice versa.

In a preferred embodiment of the device according to the present invention, this also comprises a control apparatus, either manual or automatic, for adjusting the inflating device. Preferably the inflatable body, which may either be replaceable or have a replaceable portion, is made of a material having a low tear strength, such as nylon, PVC or polyethylene, such that, when inflated, this inflatable body coming in contact with a contusive element may tear off, thereby causing a sudden drop of the measured pressure. After the inflatable body has been restored, one can restart inspecting the inside of other shoes. BRIEF DESCRIPTION OF THE FIGURES

Several embodiments of the method, and several embodiments of the device according to the present invention will be described below by way of non-limiting examples, with reference to the annexed figures, in which: Figure 1 is a diagram of a device according to a particular aspect of the present invention; Figure 2 is a three-dimensional, partially cut-away view of a shoe with an inflatable body of the type employed in the device from Figure 1 being placed therein; Figure 3 is a partially sectional, and partially cut-away side view of a shoe, with an inflatable body to be employed with the device from Figure 1 being placed therein; Figure 4 is a partial sectional view of a shoe with an inflatable body configured according to a particular aspect of the present invention being placed therein; Figure 5 is a simplified block diagram of a preferred embodiment of the method according to the present invention; and Figure 6 is a simplified block diagram of another particular embodiment of the method according to the present invention; and Figure 7 is a diagram of a particular fluid circuit that can be implemented in a device according to the present invention. DETAILED DESCRIPTION OF SEVERAL EMBODIMENTS OF THE PRESENT INVENTION

Figures 1-3 illustrate a particular embodiment of a device for inspecting the inside of a shoe according to the present invention. Generally, the device shown in Figure 1 comprises an inflatable body 1 , 4, an inflating device 2 for said body 1 , 4 with a determined fluid, and preferably though not necessarily, an apparatus 1 1 for controlling, either manually or automatically, the inflation parameters as carried out by the device 2 (such as flow rate and/or pressure and/or volume of the fluid being delivered).

When atmospheric air is used as the inflation fluid, the device 2 can simply consist of a pump with an inflow section vented to the atmosphere, whereas the device 2 can consist of a suitable pump connected to a reservoir (not shown) for the inflation fluid when a different fluid, for example an inert gas such as helium or nitrogen, or a liquid such as water is used.

This device 2 can alternatively comprise means for producing and delivering a foam (for example expanded polyurethanes) or simply comprising a valve nozzle for manual inflation. The device according to the present invention also comprises means 3 for detecting the internal pressure of the inflatable body 1 , 4, such as a common manostat. Alternatively to, or in combination with, said pressure detecting means 3, the device illustrated can comprise suitable means for detecting the force applied by the inflatable body 1 , 4 against the inner walls of a shoe 9 or 10, or vice versa, for detecting the force applied by the inner walls of the shoe 9 or 10 against the inflatable body 1 , 4, when the latter is inflated. The detecting means 3 can thus comprise manostats, force sensors, pressure gauges, load cells and weight transducers, and can be arranged on the inflatable body along one or more of the inner and/or outer walls of the latter.

In a particular embodiment of the device according to the present invention, when the device is used for detecting any contusive bodies within the shoe 9 or 10, these detecting means 3 can comprise a flowmeter being interposed between said inflating device 2 and the inflatable body 1 , 4.

Any pressure drop occurring within the inflatable body 1 , 4 may be thereby quickly detected by this flowmeter. As will be described below, Figure 7 shows a particular diagram of a fluid circuit providing the use of a flowmeter for detecting a pressure drop within the inflatable body 1 , 4.

The particular device from Figure 1 also comprises means 5, such as a display, that are capable of showing the pressure and/or force values detected by the detecting means 3 to an operator, or showing a signal related to at least one preset force/pressure value being detected. Thereby, for example, the display 5 can only warn the operator about the presence of anomalous conditions of pressure and/or force, by signalling that values have been detected which are below the lower threshold value such as defined through a previous calibration of the device, or it can signal these detected pressure/force values immediately after the inflatable body 1 , 4 has been inflated. In the latter embodiment, the means 5 can simply consist of an analogue dial (not illustrated) of the indicator of a common pressure gauge 3.

The device for inspecting the inside of a shoe as illustrated in Figure 1 also comprises a processing system 6 for the data supplied by the detecting means 3. By this processing system 6, which can be easily programmed by the operator, the pressure and/or force values detected by the means 3 can be compared with corresponding preset expected values (for example, obtained by a previous calibration of the device and stored in the system 6), or can automatically adjust, by means of the control equipment 1 1 , the inflation of the body 1 , 4, or still it can determine which information based on the pressure and/or force values being detected by the means 3 should be sent to the display 5.

This allows one to adapt the device to the various inspection procedures provided for the inside of the shoe and thereby customize the data to be made available to the operator by means of the display 5.

In the particular embodiment illustrated in the Figures 1-3, the inflatable body employed by the device described so far, is of the type comprising a single inflatable section consisting of a deformable membrane 1 being fixed to a rigid support structure 4, which carries an inflation nozzle 12, and a manostat 3 inside the membrane 1. As may be seen in Figure 1 , the manostat 3 is operatively connected to the display 5 (shown in Figure 1 ) and/or the data processing system 6 (not shown) by means of electric cables 7, whereas the nozzle 12 is fluidically connected to the inflating device 2 by means of duct 8. The deformable membrane 1 , which can be made of any elastic material, such as latex, nylon, EPR, or substantially non-elastic material, such as polyethylene, is shaped such that, when inflated, it comes in contact with at least one portion of an inner wall of the shoe 9 or 10, and is thereby subjected to a force being applied by said portion of the inner wall (even the simple constraint reaction). As may be seen in Figures 2 and 3, the membrane 1 is preferably shaped such that, after it has been inserted within the shoe 9 or 10 and suitably inflated, it abuts at least on the whole lower wall of the inside of the shoe, for example the footstraps or arch support . The membrane 1 can be made of any elastically or non-elastically deformable material, such as latex, nylon, polyethylene, polyvinylchloride (PVC), polyurethane, EPR (ethylene-propylene rubber), synthetic and natural rubbers that are capable to match the shape of the inner region of the shoe to be inspected. When the membrane 1 is made of an elastically deformable material, there results an improved adaptability of its shape to the inner region of the shoe 9 or 10.

On the contrary, a membrane 1 made of a substantially non-elastic material allows to give a particular desired shape to the inflatable body 1 , i.e. the shape considered as the one that the inner region of the shoe 9 or 10 should have in order to obtain, by means of said detecting means 3, pressure and/or force values which are more precisely related to the geometrical conditions of the inside of the shoe 9 or 10, hence to the "instep" thereof.

According to a preferred aspect of the present invention, furthermore, the material making up the deformable membrane 1 can be selected such as to have a low tear strength, such that, when the membrane 1 comes in contact with a contusive element, for example the tip of a temporary clamping element, such as a nail, hobnail, or clip, this material tears off, thereby causing a sudden pressure drop within the inflatable body 1 , 4. As will be seen below, this is a basic requirement for implementing a particular operating mode of the method for inspecting the inside of a shoe 9 or 10 according to the present invention.

This low tear strength of the membrane 1 can be obtained, as is known in the art, by carefully selecting the thickness and material of the membrane 1.

The membrane 1 of the inflatable body 1 , 4 is shaped such as to be easily replaced in the event it tears off during an inspection, or when the shape of the inflatable body 1 , 4 requires to be changed for being adapted to another shoe 9, 10 to be inspected. Alternatively, the device illustrated can comprise suitable means (not illustrated) for facilitating the replacement of the whole inflatable body 1 as a function of the various inspection requirements that may occur while using the device. As already mentioned above, when the device of the present invention is used to detect any contusive object inside the shoe 9 or 10, a circuit diagram as illustrated in Figure 7 can be employed, in combination with the use of an easily tearable material for the membrane 1 , in order to identify any tearing of the inflatable body 1 , 4.

In the particular embodiment depicted in Figure 7, the detecting means 3 can comprise a reservoir 222 and a flowmeter 203 placed downstream of the inflating device 2, which can in turn comprise an air compressor 202 and a solenoid valve (i.e. an electically operated valve) 220.

In greater detail, in the diagram from Figure 7, the inflow line of the inflating air for the body 1 bifurcates immediately downstream of the solenoid valve 220 due to a T-shaped union 221 , in order to deviate the air from the compressor 202 towards said inflatable body 1 , and also towards the reservoir 222, and said flowmeter 203 is interposed between the reservoir 222 and the inflatable body 1 , 4. The solenoid valve 220 allows to isolate the circuit tract comprising the reservoir 222, flowmeter 203 and inflatable body 1 , 4. During the operation of the device implementing this circuit from Figure 7, after the pressure inside the body 1 , and hence within the reservoir 222 has been set higher than the atmospheric pressure, for example by controlling the amount of air being fed by the compressor 202, the subsequent closure of the solenoid valve 220 would have the function of causing the isolation of the fluidic system consisting of the inflatable body 1 , reservoir 222 and flowmeter 203, such that any pressure drop of the inflatable body 1 can be immediately detected. In fact, the smaller tearing of the inflatable body 1 , in its inflated state, would result in a pressure drop within said body 1 which would cause a sudden air flow from the reservoir 222 (at a higher pressure than the ambient pressure) to the body 1 (which is torn and accordingly at ambient pressure), this air flow being immediately detected by the flowmeter 203 and the operator as well. On the other hand, when after a suitable time nothing has been detected by the flowmeter 203, the operator could deflate the body 1 and carry on inspecting another shoe.

Figure 4 shows an alternative embodiment of an inflatable body 101 a, 101 b, 101 c, 104 suitable to be inserted in the shoe 10 from Figure 3. . The inflatable body from Figure 4 consists of a plurality of deformable compartments 101 a, 101 b, 101 c hold by the same rigid support 104, which are fluidically separated, each being provided with an inflating nozzle connected to a corresponding bundle 108 of ducts directed towards an inflating device (not shown). Each compartment 101 a, 101 b, 101 c is also provided with its own force sensor 103a, 103b, 103c, which by being placed after inflating the compartments 101 a, 101 b, 101 c between the inner wall of the shoe 10, against which the compartments 101 a, 101 b, 101c are rested and the latter, has the function of detecting the force (pressure) being applied by the corresponding compartment 101 a, 101 b, 101 c against the inner rest wall of the shoe 10, or vice versa.

Preferably, the sensors 103a, 103b, 103c are load cells or weight transducers.

The signals from the sensors 103a, 103b, 103c are then sent, by means of cable 107, to a display or data processing system (not shown). As will be better understood below, by locally detecting the force (pressure) applied by the inflatable body against the inner rest wall of the shoe 10 (or more inner walls), the presence of local misshapes on the rest wall of the shoe (or on the inner walls being detected) can be assessed, by comparing this detection with the expected values that have been set in advance by way of testing.

It should be observed that, although an embodiment is described in which the local detection of the force applied by the inflatable body on at least one inner wall of the shoe, or vice versa, is associated with the presence of fluidically separated compartments of the inflatable body, this local detection can be carried out by simply arranging several sensors on the contact surface between the inflatable body and said at least one inner wall of the shoe, without any inner separation of the inflatable body being required. The division of the inflatable body into fluidically separated sectors has the main function of adapting the shape of the inflatable body within the shoe in a simple manner by changing the inflation pressure of the individual compartments, and allowing more accurate detections of the force applied by the body against the inner wall of the shoe, or vice versa, in the case of sensible geometric variations of the inner wall of the shoe to be inspected.

In view of this, the use of sensors for detecting the internal pressure (such as in the embodiment from Figures 1-3) with an inflatable body consisting of several fluidically separated compartments (such as in the embodiment from Figure 4) is not only contemplated within the scope of the present invention, but can also be particularly advantageous due to the high adaptability of the inflatable body to the shoe shape.

With reference also to Figures 5 and 6, several operating modes of the method for inspecting the inside of α shoe according to the present invention, which can be implemented for example on any of the above devices, will be described below.

Generally, the method for inspecting the inside of a shoe, according to the present invention, comprises the following steps: a) arranging an inflatable body 1 , 4; 101 a, 101 b, 101 c, 104, inside a shoe 9; 10 b) inflating with a controlled amount of a fluid, such as air, helium or nitrogen, said inflatable body 1 , 4; 101 a, 101 b, 101 c, 104 until at least one part of the inflatable body 1 , 4; 101 a, 101 b, 101 c, 104 rests on at least one portion to be inspected of an inner wall of the shoe 9, 10; c) after inflation, measuring or evaluating the internal pressure of the inflatable body 1 , 4; 101a, 101 b, 101 c, 104, or the force applied against the inflatable body by said portion to be inspected of an inner wall of the shoe 9; 10, or vice versa.

By measuring or evaluating the internal pressure of the inflatable body

1 , 4; 101a, 101 b, 101 c, 104, or the force applied against the inflatable body by at least one portion of an inner wall of the shoe 9; 10 to be inspected, or vice versa, different evaluations of the condition of the inner region of the shoe 9, 10 can be carried out. In fact, when the set of pressure and/or force values thus detected is acceptable, which set had been previously defined in a step of calibrating or setting the device, any anomaly in the geometry of the inner region of the shoe 9, 10 can be easily obtained by simply comparing the set of acceptable values as detected for a given shoe 9, 10 with this set of acceptable values.

Thus, for example, a wrong position taken for example by the footstraps, or the wrong arrangement of the reinforcements relative to the upper, or still the undesired presence of creases or folds on the arch support, or other defects that may be present inside the shoe 9, 10 can be easily detected by analyzing the signals relative to the internal pressure or the force applied by or against the inflatable body by the inspected wall, or the inspected portion thereof, of the shoe 9, 10 and comparing the same with a set of preset acceptable values. When the method of the present invention mainly aims at identifying these possible defects of the geometrical conditions of the inner region of a shoe 9, 10, and hence evaluating the "instep" of the latter, then the local detection, i.e. in several different locations (see the device described in relation with Figure 4), of the internal pressure of the inflatable body 1 , 4; 101 a, 101 b, 101 c, 104 and/or the force applied by/against the inflatable body 1 ,4 against/by the inner region of the shoe 9, 10 allows to identify not only the presence of any misshape, but also its location inside the shoe 9, 10.

Furthermore, when the inflatable body 1 , 4; 101 a, 101 b, 101c, 104 is made, at least partially, of a substantially non-elastic material and has a theoretical shape to which the inner region of the shoe should tend to, then the inflation of said body 1 , 4; 101a, 101 b, 101c, 104 within the shoe 9 or 10 and the local detection of said pressure and/or force values allows to immediately identify any anomaly of the shoe in a highly precise manner.

This method of internal inspection, which is mainly aimed at analyzing the inner geometry, i.e. the "instep" of a shoe, finds wide application in the field of the inspections carried out on prototypes of pre-series shoes, which aim at identifying any defects in the design and/or manufacture of the shoe. In this field, detecting any misshaping of the inner region of the shoe can result in changing the design and/or modifying the structure of the support last or the various parts making up the shoe in order to improve the shoe as a whole and particularly the "instep" (i.e the "fitting") thereof.

In the case where, as already stated above, the material making up the inflatable body 1 , 4; 101 a, 101 b, 101 c, 104 is at least partially selected such as to have a low tear strength, the inflation of this body 1 , 4; 101 a, 101 b, 101 c, 104 on an inner wall of a shoe 9, 10 provided with any contusive element, such as a nail, clip, or hobnail, but also an imperfect stitching, would cause this contusive element to come in contact with the tearable material and the consequent breaking of the inflatable body 1 , 4; 101 a, 101 b, 101 c, 104. This breaking would then cause a sudden pressure drop within the inflatable body 1 , 4; 101 a, 101 b, 101 c, 104 that can be identified, for example, by the detecting means 3; 103a, 103b, 103c of the devices described above, or more simply by means of an elementary visual inspection by the operator.

Therefore, if the method of inspection according to the present invention mainly aims at detecting the presence of contusive elements that may be present within a shoe 9, 10, the particular aspect of the method according to the present invention as described above allows to identify the presence of these contusive elements, through a simple visual inspection of an inflatable body, i.e. the visual evaluation of the integrity of the latter. Alternatively, in order to automatize this detection of contusive elements within the shoe 9, 10, one may arrange the detecting means 3, for example comprising the flowmeter 203 and the reservoir 222 of the diagram from Figure 7, downstream of the inflating device 2 and upstream of the inflatable body 1 , 4, such that any pressure drop within the inflatable body 1 , 4 can be readily detected. According to a preferred aspect of the present invention, not shown, the inflatable body 1 , 4; 101 a, 101 b, 101 c, 104, can have a lower portion that is intended to come in contact with the footstraps lining and/or footstraps and is made of an elastic material, such as latex, of such a thickness having a low tear strength, and an upper portion that is arranged to engage with the side inner walls of the upper, made of a non-elastic material, such as polyethylene, with a higher tear strength and, preferably, having substantially the same shape as the inner region of the shoe. Therefore, as often happens, if a contusive body such as a hobnail is present on the footstraps or footstraps lining, the inflatable body, either after or during inflation, will tear off due to the lower portion thereof, whereas in the absence of contusive bodies, this inflatable body will suitably fill the inner region of the shoe, and due to the force and/or pressure sensors, it will allow to evaluate the , "instep" according to the method described above. Figure 5 schematically illustrates a particular embodiment of the method according to the present invention, which is particularly suitable to detect any contusive elements that may be present inside a shoe 9, 10. This particular embodiment of the method of the present invention will be illustrated below, by way of example, with reference to the device from Figures 1-3 and the diagram from Figure 7.

The method from Figure 5 provides a first step (a) of arranging the inflatable body 1 , 4 within the shoe 9 or 10. In this step (a), the inflatable body 1 , 4 is deformed, for example it is folded, and accordingly it does not exert any action against the inner walls of the shoe 9 or 10.

The subsequent step (b) of inflating the body 1 , 4 in a controlled manner in order to avoid that the latter may involuntarily burst, can be preferably carried out by means of the pump 2 (or compressor 202 from Figure 7), which is controlled by the control apparatus 1 1 being, in turn, controlled by the processing system 6. The aim of this inflation step (b) is to cause at least one part of the body 1 , 4 to deform, such that said at least one part of the body 1 , 4 (consisting of the membrane 1 , in the case of Figures 1-3) comes in contact with at least one inner wall, or a portion thereof, of the shoe 9 or 10.

When the fluidic circuit from Figure 7 is used, the control apparatus 1 1 can allow the air compressor 202 to inflate the body 1 , 4 until the air within the body 1 , and also within the reservoir 222, reaches a higher pressure than the atmospheric pressure, in a preset manner. The shape of the membrane 1 can be advantageously selected such that, following the inflation step (b), it rests on the whole lower portion of the inside of the shoe 9 or 10, for example on the whole footstraps or arch support, or even it rests also on other or all the inner walls of the shoe 9 or 10. Subsequent to the step (b) of inflating the body 1 , 4 there is accordingly a step of measuring or evaluating the internal pressure of the inflatable body 1 , 4.

If the circuit from Figure 7 has been implemented, after the inflation step (b), the control apparatus 1 1 closes the solenoid valve 220 in order to isolate the circuit consisting of the reservoir 222 and inflatable body 1.

In the event that the elastically or non-elastically deformable membrane 1 has a low tear strength, i.e. it has a small thickness and is made of a suitable material, such as nylon, PVC, EPR or polyethylene, this membrane 1 coming in contact with a contusive element that may be present inside the shoe 9 or 10 can cause, as it usually does, this membrane to break and a sudden pressure drop within the body 1 , 4.

This pressure drop and the tearing of the body 1 , 4 can be then either visually identified by the operator, or as in the device from Figure 1-3, can be measured and displayed to the operator by means of for example a manostat 3 being operatively coupled to a display 5. When one or more manostats 3 are provided, possible defects within the shoe 9 or 10 being inspected can be identified by comparing the internal pressure values of the inflatable body 1 , 4 that are detected for a given shoe 9 or 10 with a set of acceptable values that have been established in advance during setting tests. This comparison can be automatically carried out by the processing system 6 as described above.

On the contrary, if the device used to implement the particular detection method from Figure 5 provides the use of the fluidic circuit from Figure 7, a tearing in the membrane 1 of the inflatable body will cause a sudden air flow from the reservoir 222 at a higher pressure than ambient pressure, to the torn inflatable body at ambient pressure, because of the pressure difference being created, the flowmeter 203 accordingly detecting this air flow. What has been detected by the flowmeter 203 can either be immediately read by an operator, or it can be sent to a suitable display 5 in case the flowmeter 203 outputs an analogue or digital signal.

After the internal pressure of the body 1 , 4 (step (e)) of the method from Figure 5) has been measured and/or evaluated, this particular method can be applied to the next shoe (step (g)), if the pressure detected matches the acceptable values, or to a subsequent examination, or repair, of shoe 9 or 10 being inspected (step (f)) can be carried out, if the membrane 1 of the body 1 , 4 is broken or the detected pressure values do not match the expected acceptable ones.

It should be understood that, the defects or contusive objects can be advantageously detected for two shoes at the same time, by simply doubling the fluidic circuit depicted herein.

The particular operating mode of the method according to the present invention, such as shown in the diagram from Figure 6 is particularly suitable to inspect the inner region of a shoe mainly aiming at identifying any geometrical defects of the inner parts of the shoe, and therefore evaluate the "instep" thereof. Reference will be made to the device described relative to Figure 4, only by way of example. Similarly to the method depicted in Figure 5, the method from Figure 6 provides two initial steps (a') and (b') of arranging the inflatable body 101 a, 101 b, 101 c, 104 within the shoe 10, and inflating said body 101 a, 101 b, 101 c, 104, respectively.

In the case where the inflatable body is divided into fluidically separated compartments 101a, 101 b, 101c, the step (b') of inflating the inflatable body can provide inflating under varying conditions (for example with a different pressure) for each compartment 101 a, 101 b, 101 c in order to adapt the shape of the inflatable body 101 a, 101 b, 101 c to the inner region of the shoe 10 in an optimum manner. Since the inspection method from Figure 6 is not particularly intended for detecting contusive elements that may be present inside the shoe 10, the inflatable body 101 a, 101 b, 101 c, 104, or better the deformable membrane thereof, may not have a low tear strength, though, however, this characteristic is obviously preferred, because it scarcely, if at all, affects the detection of the geometrical defects within the shoe 10 and is however used to identify the presence of these contusive elements in a useful manner.

In order to detect defects that may be present within the shoe 10, the subsequent step (c') of the method depicted in Figure 6 provides that the force applied by the body 101 a, 101 b, 101 c, 104, when inflated, against the contact walls of the inner region of the shoe 10 is locally measured by means of a certain number of suitable sensors 103a, 103b, 103c.

As already stated above, by locally measuring this force one can not only detect any anomaly in the geometrical . configuration of the various inner parts of the shoe 10, but also identify their location within the shoe 10 with a certain ease.

By comparing (step (d')) the detected local values of the force applied by the inflatable body 101a, 101 b, 101c, 104 with corresponding acceptable expected values, which had been previously defined during a calibration step, one can easily find out whether an anomaly is present within the shoe 10. These anomalies, which may be due not only to errors made during the manufacture, but also to errors made during the design of the shoe 10, can be then subsequently identified in a precise manner and, if possible, they can be corrected (step (f)), in order to avoid that the shoe 10 is uncomfortable for the end user (i.e., in order to avoid that anomalies or defects may occur in the "instep"). In the case where no anomalies are detected, the method from Figure 6 provides that the same method (step (g')) is applied to the next shoe 10 to be inspected.

According to a preferred aspect of the present invention, in the course of several tests that have been carried out by the Inventors, the method for inspecting the inside of a shoe as claimed herein has been found to be particularly effective when the same is performed after the soling, i.e. when the last is removed from an almost completed shoe, and when the same is performed at the end of the subsequent finishing of the shoe, i.e. before the packaging and distribution of the latter. More particularly, the application of the method as described above, either before or after the finishing of the shoe, has been found to be particularly effective in identifying the presence of contusive elements and/or geometric defects that may be present inside the shoe.

Claims

1. A method for inspecting the inside of α shoe, comprising the following steps: α. arranging at least one inflatable body within the shoe; b. inflating, by means of a controlled amount of fluid, said at least one inflatable body within the shoe until said at least one inflatable body, or a part thereof, is substantially rested on at least one portion of an inner wall of the shoe. c. after inflation, measuring or evaluating the internal pressure of said at least one inflatable body and/or the force applied by said at least one portion of an inner wall of the shoe against said at least one inflatable body, or vice versa.

2. The method according to claim 1 , characterized in that it comprises a subsequent step of comparing the internal pressure of said at least one inflatable body and/or the force applied against said at least one inflatable body or by said at least one inflatable body, with the pressure, and /or the force, expected after inflation.

3. The method according to claim 1 , characterized in that said step of measuring or evaluating the internal pressure and/or the force applied against/by said at least one inflatable body comprises a step of checking the integrity of said at least one inflatable body.

4. The method according to one of preceding claims, characterized in that said step of measuring or evaluating the internal pressure of said at least one inflatable body and/or the force applied against/by said at least one inflatable body provides the local detection of the pressure within at least one inflatable body and/or the force locally applied by said at least one portion of an inner wall against said at least one inflatable body, or vice versa.

5. The method according to any preceding claim, wherein said at least one inflatable body is divided in two or more fluidically separated compartments and said step of measuring or evaluating the internal pressure and/or the force applied against/by said at least one inflatable body is carried out for each of said two or more compartments.

6. The method according to any preceding claim, wherein said at least one inflatable body is at least partially made of a material having a low tear strength.

7. The method according to claim 6, wherein said material is selected from: latex, a polyamide (nylon), polyethylene, polyvinylchloride (PVC), polyurethane, EPR (ethylene-propylene rubber), synthetic and natural rubbers, silicone resins.

8. The method according to any preceding claim, wherein the inflating fluid of said at least one inflatable body is selected from: air, helium, nitrogen, water, expanded polyurethane foams.

9. The method according to any preceding claim, characterized in that said at least one inflatable body, when inflated, substantially rests on the whole extension of the footstraps or arch support of the shoe.

10. The method according to any preceding claim, characterized in that said at least one inflatable body, when inflated, substantially rests on the whole inner surface of said shoe.

1 1.The method according to any preceding claim, characterized in that it is applied during the manufacture of a shoe subsequent to the soling, but prior to the subsequent finishing operations.

12. The method according to any preceding claim, characterized in that it is applied during the manufacture of a shoe at the end of the finishing operations.

13. The method according to claims 1 1 and 12, characterized in that it is applied during the manufacture of a shoe both immediately after the soling and at the end of the finishing operations.

14.The method according to any preceding claim, characterized in that it is applied to a prototype or pre-series shoe during a design step for the shoe and/or the support last.

15. The method according to any preceding claim, characterized in that said inflatable body, when inflated, has a shape substantially corresponding to the. inner shape that said shoe to be inspected should theoretically have.

16. A device for inspecting the inside of a shoe, characterized in that it comprises at least one inflatable body, a device for inflating said at least one inflatable body, by means of a pre- established fluid, and means for detecting, either directly or indirectly, the internal pressure of said at least one inflatable body after it has been inflated and/or the force applied by the external environment against said at least one inflatable body, when inflated, or vice versa.

17. The device according to claim 16, characterized in that said inflating device is controlled by a control apparatus, either of the manual or automatic type.

18. The device according to claim 16 or 17, characterized in that said means for detecting the internal pressure of said at least one inflatable body and/or the force applied against/by said at least one inflatable body are operatively connected to means for displaying to the operator said pressure and/or said force or a signal related to at least one value of said pressure or said force.

19. The device according to any claims 16, 17 or 18, characterized in that it comprises a data processing system that is functionally connected to said inflating device and/or to said means for detecting the pressure and/or the force, and /or to said means for displaying said pressure and/or said force or a signal related to at least one value of said pressure or said force.

20. The device according to any claim 16 to 19, characterized in that said at least one inflatable body, or a part thereof, can be freely replaced.

21. The device according to any claim 16 to 20, characterized in that said at least one inflatable body comprises a rigid support portion and at least one inflatable elastic membrane.

22. The device according to any claim 16 to 21 , wherein said at least one inflatable body is divided in fluidically separated compartments.

23. The device according to any claims 16 to 22, characterized in that said at least one inflatable body comprises at least one membrane for contacting at least one portion of an inner wall of said shoe, said membrane being shaped such as to have a low tear strength.

24. The device according to any claim 16 to 23, characterized in that said at least one inflatable body has at least one portion that is made of an elastic material.

25. The device according to any claim 16 to 24, characterized in that said at least one inflatable body has at least one membrane made of a material selected from: latex, a polyamide (nylon), polyethylene, polyvinylchloride (PVC), polyurethane, EPR (ethylene-propylene rubber), synthetic and natural rubbers, silicone resins.

26. The device according to any claim 16 to 25, characterized in that said inflatable body has at least one lower membrane that is shaped to have a low tear strength and at least one side and/or upper membrane having a higher tear strength than said lower membrane.

27. The device according to any claim 16 to 26, wherein said means for detecting the pressure of said at least one inflatable body after inflation and/or the force applied by the external environment against said at least one inflatable body when inflated, or vice versa, are selected from: manostats, force sensors, pressure gauges, load cells, weight transducers.

28. The device according to any claim 16 to 26, characterized in that said means for detecting, either directly or indirectly, the pressure of said at least one inflatable body and/or the force applied by the external environment against said at least one inflatable body comprise at least one flowmeter being interposed between said inflating device and said at least one inflatable body.

29. The device according to claim 28, characterized in that said means for detecting, either directly or indirectly the pressure of said at least one inflatable body and/or the force applied by the external environment on said at least one inflatable body also comprise at least one reservoir fluidically connected to said at least one inflatable body, said at least one flowmeter being interposed between said reservoir and said at least one inflatable body, the fluidic circuit comprising said at least one reservoir, said at least one inflatable body and said flowmeter being isolable relative to said inflating device.

30. The device according to any claim 16 to 29, characterized in that said inflatable body, when inflated, has a shape substantially corresponding to the inner shape that said shoe to be inspected should theoretically have.