METHOD FOR VERIFYING THE EXECUTION OF A PROCEDURE OF MOUNTING/DEMOUNTING TIRES ON/FROM RESPECTIVE RIMS OF VEHICLE WHEELS USING AN APPARATUS FOR HANDLING VEHICLE WHEELS, AND APPARATUS THEREFOR

Abstract

Apparatus and method for mounting a tire on a wheel rim and/or for removing a tire from a vehicle wheel rim. Such an apparatus is usually known as a tire changer. The tire changer of the present invention is capable of verifying that the position of the inflation valve and/or of the TPMS sensor of the wheel, relative to the position of the portions of tire most subject to stresses and/or relative to the position of the mounting/demounting tools, as well as the intensity of such stresses, lie within ranges defined as acceptable. The result of such verifications is then made available via a suitable report document.

Claims

1. Method for verifying the execution of a procedure of mounting/demounting a tire on/from a rim of a vehicle wheel, in the context of a process of wheel maintenance, comprising the steps of: mounting a wheel on a rotary support of a vehicle wheel maintenance apparatus, said wheel comprising a respective rim, said apparatus comprising an electric motor for putting the rotary support into rotation and at least one tool for demounting a tire from the rim or for mounting the tire on the rim; identifying a position of at least one reference point on the rim; putting the rotary support into rotation to position the wheel in a position in which the at least one reference point on the rim is located at a predetermined distance from the at least one demounting or mounting tool; and then executing the procedure of demounting the tire from the rim or mounting the tire on the rim; determining at least one position, and at least one respective value, of stress applied by the rim and/or by the demounting or mounting tool to the tire; calculating an angular distance between the position of the at least one reference point on the rim and the at least one position of stress applied by the rim and/or by the demounting or mounting tool to the tire, characterized in that it comprises the steps of: verifying that the angular distance between the position of the at least one reference point on the rim and the at least one position of stress applied by the rim and/or by the demounting or mounting tool to the tire lies within a predetermined range of acceptable distances, said range of acceptable distances being stored in memory mean accessible by a control unit associated with the vehicle wheel maintenance apparatus; verifying that the at least one respective value of stress applied by the rim and/or by the demounting or mounting tool to the tire lies within a predetermined range of acceptable stress values, said range of acceptable stress values being stored in said memory means accessible by the control unit associated with the vehicle wheel maintenance apparatus, and making the results of the preceding verification steps available.

2. Method according to claim 1, wherein the step of making the results of the preceding verification steps available comprises the steps of: storing the at least one position of stress applied by the rim and/or by the demounting or mounting tool to the tire in said memory means; storing the at least respective value of stress applied by the rim and/or by the demounting or mounting tool to the tire in said memory means; creating, in said memory means, a report document comprising data relating to the at least one position, and to the at least respective value, of stress applied by the rim and/or by the demounting or mounting tool to the tire, sharing said report document.

3. Method according to claim 1, wherein the step of making the results of the preceding verification steps available comprises the step of: printing the results, using a printer.

4. Method according to claim 1, wherein the step of making the results of the preceding verification steps available comprises the step of: displaying the results on a screen.

5. Method according to claim 1, further comprising the step of: sending the results of the preceding verification steps to a remote computer system, of the cloud type for example.

6. Method according to claim 1, wherein the step of determining at least one position, and at least one respective value, of stress applied by the rim and/or by the demounting or mounting tool to the tire comprises the step of: correlating a measurement of the rotational position of the electric motor and/or of the rotary support and/or of the wheel with a measurement of the resistive torque applied to the electric motor and/or with a measurement of the current draw of the electric motor and/or with a measurement of the rotation speed and/or acceleration of the electric motor and/or of the rotary support and/or of the wheel.

7. Method according to claim 6, further comprising the following steps: determining at least one value of diameter of the wheel; determining at least value of force applied by the rim and/or by the demounting or mounting tool to the tire, on the basis of the at least one value of stress applied by the rim and/or by the demounting or mounting tool to the tire, and on the basis of the at least one value of diameter of the wheel, and verifying that the at least one value of force applied by the rim and/or by the demounting or mounting tool to the tire lies within a predetermined range of acceptable force values, said range of acceptable force values being stored in said memory means accessible by the control unit associated with the vehicle wheel maintenance apparatus.

8. Method according to claim 1, wherein the step of identifying the position of the at least one reference point on the rim comprises the steps of: graphically displaying the wheel on an input/output device interfaceable with the wheel maintenance apparatus, with the wheel divided into a plurality of parts; using the input/output device for associating the position of the at least one reference point on the rim with a part selected from the plurality of parts into which the wheel is graphically divided, and calculating said predetermined distance of the at least one reference point on the rim from the at least one demounting or mounting tool as the distance of the at least one demounting or mounting tool from a point belonging to the part associated with the position of the at least one reference point on the rim.

9. Method according to claim 1, wherein the step of executing the procedure of demounting the tire from the rim or mounting the tire on the rim is controlled automatically by the control unit associated with the vehicle wheel maintenance apparatus, so as to keep the angular distance between the position of the at least one reference point on the rim and the at least one position, and the at least one respective value, of stress applied by the rim and/or by the demounting or mounting tool to the tire within respective predetermined ranges of acceptable distances and acceptable values of stress.

10. Method according to claim 1, wherein the at least one reference point on the rim comprises an inflation valve or a TPMS sensor or a spoke.

11. Vehicle wheel maintenance apparatus, comprising: a base; a rotary support mounted on the base and capable of receiving and supporting a rim of a wheel of a vehicle, said rim having at least one reference point; an electric motor, associated with the base, for putting the rotary support into rotation; at least one tool for demounting a tire from the rim or for mounting the tire on the rim; a control unit capable of actuating the electric motor for positioning the wheel in a position in which the at least one reference point on the rim is located at a predetermined distance from the at least one demounting or mounting tool, said control unit having access to memory means; a rotation sensor, operationally connected to the control unit, for measuring the position and/or rotation speed and/or acceleration of the electric motor and/or of the rotary support and/or of the wheel; detector means, operationally connected to the control unit, for measuring a resistive torque applied to the electric motor and/or a current draw of the electric motor; the control unit being capable of identifying at least one position, and at least one respective value, of stress applied by the rim and/or by the demounting or mounting tool to the tire, and of calculating an angular distance between the position of the at least one reference point on the rim and the at least one position of stress applied by the rim and/or by the demounting or mounting tool to the tire, characterized in that the control unit is capable of verifying that the angular distance between the position of the at least one reference point on the rim and the at least one position of stress applied by the rim and/or by the demounting or mounting tool to the tire lies within a predetermined range of acceptable distances stored in said memory means, and that the at least one respective value of stress applied by the rim and/or by the demounting or mounting tool to the tire lies within a predetermined range of acceptable stress values stored in said memory means, and in that the control unit is capable of making the results of said verifications available.

12. Apparatus according to claim 11, wherein the control unit is capable of storing the at least one position, and the at least one respective value, of stress applied by the rim and/or by the demounting or mounting tool to the tire in said memory means; the control unit also being capable of creating, in said memory means, a report document comprising at least data relating to the at least one position, and the at least one respective value, of stress applied by the rim and/or by the demounting or mounting tool to the tire, and of sharing said report document.

13. Apparatus according to claim 11, wherein the control unit is operationally connected to a printer in order to print the results of said verifications.

14. Apparatus according to claim 11, wherein the control unit is operationally connected to a screen in order to display the results of said verifications.

15. Apparatus according to claim 11, wherein the at least one reference point on the rim comprises an inflation valve or a TPMS sensor or a spoke.

16. Apparatus according to claim 11, wherein the memory means accessible by the control unit are at least partially located in the vehicle wheel maintenance apparatus.

17. Apparatus according to claim 11, wherein the memory means accessible by the control unit are at least partially located in a remote computer system, of the cloud type for example.

18. Apparatus according to claim 11, wherein the memory means accessible by the control unit are at least partially located in a portable device, for example a tablet or a smartphone.

19. Apparatus according to claim 11, wherein the control unit is capable of controlling the vehicle wheel maintenance apparatus automatically, so as to keep the angular distance between the position of the at least one reference point on the rim and the at least one position, and the at least one respective value, of stress applied by the rim and/or by the demounting or mounting tool to the tire within respective predetermined ranges of acceptable distances and acceptable values of stress stored in said memory means.

20. Apparatus according to claim 11, comprising an input/output device capable of graphically displaying the wheel with the wheel divided into a plurality of parts, the input/output device being operable by an operator for the purpose of selecting a part, from among the plurality of parts into which the wheel is divided, to be associated with the position of the at least one reference point on the rim; the control unit being capable of calculating the predetermined distance of the at least one reference point on the rim from the at least one demounting or mounting tool, as the distance of the at least one demounting or mounting tool from a point belonging to the part associated with the position of the at least one reference point on the rim.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0085] This description is set out below with reference to the appended drawings, which are provided for guidance only and which are therefore non-limiting, in which:

[0086] FIG. 1 shows, in an axonometric view, an example of a tire changer according to the invention;

[0087] FIG. 1a shows, in an axonometric view, an example of a vehicle wheel, that is to say an assembly consisting of a rim and tire mounted thereon;

[0088] FIG. 2 illustrates, by way of example, a portion of a vehicle wheel rim, having an inflation valve and TPMS sensor associated therewith, of the type usually subjected to the maintenance processes using apparatuses according to the present invention;

[0089] FIG. 2a shows, by way of example, a vehicle wheel rim having a TPMS sensor of the “strip” type mounted on the opposite side to the inflation valve, of the type usually subjected to the maintenance processes using apparatuses according to the present invention;

[0090] FIG. 3 reproduces a graph, known from the document “wdk guideline for examination of tire technology—Test guideline for tire changers”, which shows the variation over time of the forces (expressed in kN) exerted on the rim by the tire bead in the course of the process of mounting the tire on a respective rim (duration expressed in seconds);

[0091] FIG. 4 reproduces a graph, known from the document “wdk guideline for examination of tire technology—Test guideline for tire changers”, which shows the variation over time of the forces (expressed in kN) exerted on the rim by the tire bead in the course of the process of demounting the tire from a respective rim (duration expressed in seconds);

[0092] FIG. 5 reproduces a possible example of a report document including data relating to the procedure for mounting and demounting tires on/from respective rims, together with identification data of the wheels and of the vehicle to which the wheels relate. Such a report document makes it easy to verify whether the mounting/demounting procedure has been executed to a professional standard without damaging any component of the wheel;

[0093] FIG. 6 shows schematically, during the operations of demounting the tire from the wheel, shown here in plan view, the recommended areas in which it is desirable to position the TPMS sensor relative to the mounting/demounting tools, at the start of the demounting process; an approximate indication is also given of the areas in which, during said demounting process, the stresses applied to the tire bead by the rim usually develop;

[0094] FIG. 6a shows schematically, at the conclusion of the operations of demounting the tire from the wheel, shown here in plan view, the approximate position in which it is desirable for the TPMS sensor to be located relative to the mounting/demounting tools;

[0095] FIG. 7 shows schematically, during the operations of mounting the tire on the wheel, shown here in plan view, the recommended areas in which it is desirable to position the TPMS sensor relative to the mounting/demounting tools at the start of the mounting process; an approximate indication is also given of the areas in which, during said mounting process, the stresses applied to the tire bead by the rim usually develop;

[0096] FIG. 7a shows schematically, at the conclusion of the operations of mounting the tire on the wheel, shown here in plan view, the approximate position in which it is desirable for the TPMS sensor to be located relative to the mounting/demounting tools.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS OF THE INVENTION

[0097] In the following description, any expressions used, such as “right”, “left”, “above”, “below”, “upper”, “lower”, “horizontal”, “vertical” and the like, are provided purely for illustrative purposes and refer to the particular arrangement of elements present in the attached figures, and are therefore non-limiting in nature.

[0098] With reference to the attached figures, the number 1 indicates the whole of a vehicle wheel maintenance apparatus, particularly a tire changer.

[0099] The apparatus 1 illustrated in FIG. 1 is a tire changer, that is to say a device for mounting tires 2 on a rim 3 of a wheel 4 and/or for demounting tires 2 from a rim 3. A tire usually comprises a tread and two sidewalls which terminate in respective beads, which are the elements for coupling the tire to the rim. An example of a wheel 4, that is to say an assembly consisting of a rim 3 and a tire 2, is illustrated in 1 a. FIG. 1a also shows how, when the tire 2 is mounted on the rim 3, the operator is usually still able to observe the position of the inflation valve V, but not that of the TPMS sensor.

[0100] The apparatus 1 comprises a base 5 to be placed on the ground. On the base 5 there is mounted a rotatable support 6 formed by a vertical shaft at the upper end of which are arranged support means, of the central locking type for example (known in the technical jargon as a back-up plate or centre post) or of the self-centring plate type, all of which are known systems, comprising, for example, as illustrated in FIG. 1, a self-centring plate 6 for receiving and supporting the rim 3 of the wheel 4, and locking means, for example gripping clamps 60, for fixing the rim 3 integrally to the self-centring plate.

[0101] The rim 3 of the wheel 4 has an inflation valve V of a known type for inflating and/or deflating the tire 2. On the rim 3, usually at the position of the valve V, there may also be a device (TPMS, or Tire Pressure Monitoring System) for monitoring the pressure of the tire, also of a known type, and illustrated schematically in FIG. 2 where it is indicated by the letter T. On the other hand, FIG. 2a illustrates a rim 3 having a TPMS sensor of the “strap” or “band” type, that is to say a sensor fixed to a metal strip wrapped around the rim, the sensor being positioned at 180° to the position of the inflation valve V.

[0102] The self-centring plate 6 is rotatable on the base 5 about its main axis A and is connected to an electric motor, which for example may be positioned inside a casing of the base 5 and not illustrated. The motor is configured to make the self-centring plate 6 and the wheel 4 rotate together about the main axis A of the self-centring plate shaft 6 (which coincides with the main axis, or axis of rotation, of the wheel 4). The base 5 comprises a column 7 extending vertically. The column 7 is substantially parallel to the shaft of the self-centring plate 6 and carries at least one mounting and/or demounting tool 8, of a known type and not described in detail, capable of mounting and/or demounting a tire 2 on/from the rim 3. The mounting/demounting tool 8 is configured to come into contact with the sidewalls of the tire 2 from above and/or from below in the proximity of the beads of the tire 2, which, when said tire 2 is mounted on the rim 3, lie behind two retaining flanges of the rim 3.

[0103] The apparatus 1 comprises a control unit 9 (not illustrated in the figure) for actuating the electric motor. The control unit 9 is configured to send control signals to the electric motor, and this operation is directed by an operator via a user interface (which may, for example, comprise push buttons, pedals, a touch screen, etc.) connected to the control unit.

[0104] At least one actuator, of a known type and not described in detail, is operationally connected to the mounting/demounting tool 8 and is connected to the control unit 9 of the apparatus 1. The control unit 9 is configured to send control signals to the actuator so as to control the mounting/demounting tool 8 for the purpose of mounting or demounting a tire 2 on/from the rim 3. This operation is also directed by an operator via a user interface (comprising, for example, push buttons, pedals, a touch screen, etc.) connected to the control unit. Alternatively, for tire changers of the traditional, or lever, type, the operator performs the mounting/demounting operation manually.

[0105] The control unit 9 is usually capable of knowing the position of the mounting/demounting tool 8 relative to at least one or more reference points, for example relative to the column 7, the base 5, the self-centring plate 6, the wheel 4, or other. Preferably, the control unit 9 is usually capable of knowing the position of the mounting/demounting tool 8 relative to at least the self-centring plate 6.

[0106] Typically, the apparatus 1 has a rotation sensor 11 (known and not illustrated in the figures), which for example comprises an encoder, preferably of the optical or capacitive type, associated with the shaft of the self-centring plate 6 and/or with the shaft of the electric motor connected to it, and is suitably interfaced with the control unit 9.

[0107] The rotation sensor, which for example comprises an encoder, preferably of the magnetic type in this case, could alternatively be mounted inside the electric motor.

[0108] In any case, as a result of an initial calibration procedure, the control unit 9 is capable of correlating the position of the tool 8 with the rotational position of the self-centring plate 6 and therefore of the wheel 4 fixed to it.

[0109] The apparatus 1 also comprises an input/output device 10, capable of graphically displaying the wheel to be worked on and operationally connected to the control unit 9.

[0110] This device may be part of the more general user interface by means of which the operator controls, via the control unit, the electric motor and/or the at least one actuator connected to the mounting and demounting tool.

[0111] Alternatively, said input/output device may be specifically dedicated to the display of the wheel, and may only optionally include supplementary functions for the convenience of the operator.

[0112] The input/output device 10 is mounted on any type of arm connected to the column 7, for supporting the mounting and demounting tool 8 in a convenient position for the operator.

[0113] The input/output device 10 comprises a screen, of the touch screen type, by means of which the wheel can be graphically displayed. As an alternative to the touch screen, a conventional screen may be used, connected if necessary to a manual input device (a thumb wheel, push buttons, or the like) for identifying the angular sector of the TPMS sensor, as explained below.

[0114] In any case, on the screen of the input/output device, the wheel 4 is graphically divided into a plurality of parts, shown as circular sectors.

[0115] The wheel is, for example, shown in a top view, and its upper circular sectors, that is to say those located near the upper part of the area of the screen dedicated to the display of the wheel, correspond, in physical reality, to the sectors of the wheel positioned near the vertical column 7 which is on the opposite side of the wheel to the operator.

[0116] In a possible variant, the upper sectors of the wheel, in the graphic display, correspond in physical reality to the sectors of the wheel positioned near the mounting/demounting tool.

[0117] In any case, the identification, even if approximate, of the circular sectors on the graphic display, relative to the corresponding sectors that theoretically refer to the physical wheel, is always easily and immediately understandable for the operator, independently of the type of graphic display used, which may even be purely approximate and/or abstract.

[0118] Thus, using the input/output device 10, the operator indicates the angular position of the TPMS sensor to the control unit 9.

[0119] By using the rotation sensor 11, it is then possible to know how the angular position of the TPMS sensor changes, relative to the position initially indicated by the operator, during the wheel maintenance procedure.

[0120] The rotation sensor 11, operating independently if provided with appropriate on-board electronics, or operating with the assistance of the control unit 9 of the tire changer 1 if necessary, can detect the rotational position and/or, if necessary, the speed and acceleration of the self-centring plate 6 and/or of the shaft of the electric motor and/or of the wheel fixed to the self-centring plate.

[0121] The apparatus 1 is also provided with suitable detector means 12, known and not illustrated, for detecting the current drawn by the electric motor. Said detector means 12 may, for example, be a Hall effect sensor, or a current measuring resistor, or a current transformer or the like. As an alternative or in addition to what is described above, the detector means could also comprise at least one torque measuring device, such as a torquemeter, accelerometer or other.

[0122] In any case, both the rotation sensor 11 or the detector means 12 are connected to the control unit 9, which uses the detections performed by such tools to identify at least one position of maximum tension applied by the rim 3 and/or by the at least one mounting/demounting tool 8 to the tire 2, for example to the sidewall and/or to the bead of the tire.

[0123] The variation of the tension imparted to the rim, being applied thereto by the tire bead during the procedure of mounting or demounting respectively, is known on the basis of these detections (see FIGS. 3 and 4 respectively), and as a result of the knowledge of the type of maintenance operation to be performed (mounting or demounting). Said tensions, measured by the German organization wdk by using an appropriate, suitably instrumented, rim, are also indicative of similar constraint reactions exerted by the rim, which is much more rigid than the tire, on the tire itself, and particularly on the sidewall and beads of the tire, which will thus be stressed by contact with the rim.

[0124] As shown in FIGS. 3 and 4, such tensions usually show different variations according to the type of maintenance operation, and may comprise one or more tension peaks, that is to say moments at which the tensile stress to which the rim (or the tire, depending on the point of view) reaches a maximum in specific steps of the procedure. These aspects, which are fully documented in the wdk procedures, are well known to those skilled in the art and will not be described in detail.

[0125] The current actually drawn by the electric motor, and detected by the detector means 12, can easily be correlated with the resistive torque applied to the electric motor, and therefore with the tensile stresses imparted to the tire bead by the rim; consequently, it is possible to know, because of the results of detection obtained from the rotation sensor 11, the angular positions of the wheel at which the tire is subjected to high-tension states, and which would therefore cause probable damage or might cause damage to the TPMS sensor when the latter comes into contact with the tire bead portion subjected to high-tension states.

[0126] If the procedure of mounting the tire on the rim and/or the procedure of demounting the tire from the rim is carried out to a professional standard, the TPMS sensor should never be positioned, at the start or end of the procedure or in the course thereof, within or near the areas affected by such high-tension states.

[0127] The control unit 9 of the tire changer 1 is capable of calculating the angular distance between the position of the TPMS sensor, considered as a reference point on the rim for example (and/or of the inflation valve V if the TPMS sensor is associated with the valve or is placed at a known distance from the valve, for example at 180° from it), and the positions of high stress of the tire bead.

[0128] Such positions of high stress comprise both the positions at which the tension reaches a maximum, that is to say the positions of peak tension, and the positions adjacent to such peak positions.

[0129] In general, therefore, it is possible to define larger or smaller ranges of rotation in which the TPMS sensor should never be located, and it is clearly possible to draw up a hierarchy of risk corresponding to respective threshold values of stress in order to define the more or less risky angular ranges, in terms of mechanical stresses and respective rotational positions, in which the valve and/or the TPMS sensor should or should not be located at the end or the beginning of the procedure or in the course thereof.

[0130] The control unit 9 is usually also capable of mapping the variation in stresses to which the tire is subjected by the rim and/or by at least one mounting/demounting tool along the whole circumference of the wheel. Thus it is possible to ensure that the tire is not subjected to stresses that might damage it.

[0131] The control unit 9 can access memory means 13 (known and not illustrated in the figures) comprising information about the ranges of distances considered acceptable between the valve and/or the TPMS sensor and the portions of tire stressed by contact with the rim and/or tools, and about the ranges of respective values of stress that are also considered acceptable both as regards the integrity of the TPMS sensor and/or valve and that of the tire.

[0132] Such ranges of acceptable values may be established in advance by the manufacturer of the tire changer (and possibly updated periodically), or may be determined by the operator, on the basis of the type of wheel to be worked on, for example.

[0133] The memory means 13 may reside directly in the tire changer 1, or may be partially or completely located in an external computer system; for example, it may reside in a server in the workshop where said tire changer is located, or in a portable device available to the operator, or may be located elsewhere, for example in a remote computer system of the cloud type.

[0134] The control unit 9 is governed by a computer program containing instructions for controlling the tire changer, according to the present invention. Said computer program resides in further memory means 14 that may be the same as the aforesaid memory means 13 accessible by the control unit 9, or may be different from these.

[0135] Said computer program may also be periodically updated; for example, the memory means 14 may be set up to receive periodic updates carried out, or at least approved, by the manufacturer of the tire changer, either by the intervention of an authorized technician or by means of automatic updating procedures executed by remote control, if this is considered appropriate and if the tire changer is connected to a network.

[0136] In the course of the mounting and/or demounting process, the control unit 9 therefore verifies that the calculated angular distances between the valve and/or the TPMS sensor and the stressed portions of the tire, as well as said stress values, lie within said ranges defined as acceptable.

[0137] The outcomes of these verifications are made available at the end of the wheel maintenance operation, for example by means of a report document such as that illustrated by way of example in FIG. 5, which may, as required, be printed, displayed on a display provided on the tire changer (for example, it may be displayed directly on the display provided on the input/output device 10), and/or displayed remotely (for example, on a video terminal connected to the computer system of the workshop or to a cloud system, on a portable device available to the operator, etc.).

[0138] Said report document may comprise information on the particular make and model of tire changer used, including the serial number.

[0139] There will also be information relating to the date and time of the mounting/demounting operation, and identification data of the vehicle to which the wheel (or the wheel train) relates, for example the registration number and/or the VIN code.

[0140] Preferably, the report document includes information relating to all the wheels of the vehicle subjected to either the demounting or the mounting operation.

[0141] It may also include information on the type, characteristics and dimensions of the rim and/or the tire, on the type of TPMS sensor used (where present) and on the state of wear of the wheel components, for example the state of wear of the tire and particularly of the tread, and/or on the level of functionality of the TPMS sensor. If necessary, it may contain suggestions about the need to dispose of excessively worn tires and/or faulty components, or may provide information about the location in the warehouse of tires to be stored in the workshop.

[0142] The report document may if necessary also comprise data relating to the name and address of the workshop where the maintenance operation took place, the name and address of the customer, etc.

[0143] As a general rule, the report document may, for example, be personalized according to the specific preferences of the workshop carrying out the maintenance, or in terms of its graphics or contents.

[0144] Preferably, the report document comprises data for the unique identification of the tire and/or the rim and/or the wheel as a whole. For example, such data may be obtained from an RFID sensor mounted on the tire changer, for reading corresponding RFID tags associated with the tires. In addition or as an alternative to the RFID system, any other identification technology may be used (for example, NFC or optical identification using bar or QR codes, etc.).

[0145] When the wheel or the wheel components (tire, TPMS sensor, rim, etc.) have been identified, corresponding information may be retrieved, for example, from data banks contained in memory means accessible to the control unit, possibly from remote data banks, of the cloud type for example, etc.

[0146] Such data banks may be of either the public or the private type (created by the manufacturer of the tire changer or by the tire manufacturer, for example), and may be either free or paid for.

[0147] Preferably, the tires are identified by RFID technology according to the ISO 20909, ISO 20910, ISO 20911, and ISO 20911 standards, and the tire data are made accessible according to GDSO (Global Data Service Organization) protocols. In the report document illustrated in FIG. 5, it can be seen that there are eight different graphic representations, one for each wheel of the vehicle (in the example, the vehicle concerned has four wheels), relating to both the mounting and the demounting operations. In total, therefore, the report document illustrated in FIG. 5 contains eight graphic representations of the wheel.

[0148] In the case of vehicles having a larger number of wheels (such as heavy goods vehicles), the number of graphic representations will increase accordingly.

[0149] In said graphic representations, the wheel is shown, for example, in a top view, divided into circular sectors, preferably in a similar way to its representation on the screen of the input/output device 10 discussed above.

[0150] In said representations, the circular sectors may be coloured differently. For example, the presence of a coloured sector may indicate that this sector has been subjected to a particular stress. Different types of colours may also be used for better representation of the different stress intensities to which the different sectors of the tire have been subjected.

[0151] In the report document illustrated in FIG. 5, the portions, or circular sectors, subjected to high stresses are indicated by 400. In the example of FIG. 5, the portions 400 shown are indicative of the stresses encountered throughout the mounting/demounting procedure. However, other types of representation are evidently possible: for example, the representation may relate solely to the portions stressed beyond a predefined stress threshold, etc.

[0152] The report document may relate to, and graphically report in terms of the representation 400 of the most stressed sections, only the values relating to the mounting/demounting operations that concern the upper bead of the tire, or only the values concerning the lower bead, or both. In the latter case, the representation 400 of the most stressed sections could relate solely to the maximum values recorded between the upper and lower beads, or a sum or a mean or any other combination of these values.

[0153] The graphic representation of the wheel may also comprise the indication of the position, preferably at the start of the mounting/demounting procedure, of the inflation valve and/or of the TPMS sensor.

[0154] In the report document illustrated in FIG. 5, the position of the inflation valve and/or of the TPMS sensor at the start of the mounting/demounting procedure is indicated by T0.

[0155] If the report document is displayed on a screen, both the graphic representation of the particularly stressed circular sectors and the position of the valve and/or the TPMS sensor may be modified in real time, on the basis of the values observed and/or measured on the tire changer in the course of the operation.

[0156] The graphic representation of the inflation valve and/or the TPMS sensor may usefully provide for the use of a particular colouring, green for example, to indicate that, during the mounting/demounting operation, the valve and/or sensor have never been located within or close to portions of the tire stressed beyond the threshold values defined as acceptable.

[0157] If this has unfortunately occurred, however, it is possible to provide for the use of a red colouring, or an orange colouring, for example, in the case of borderline or otherwise doubtful situations where further verifications are needed, for the graphic representation of the valve and/or the TPMS sensor.

[0158] A further possible method of indicating that the mounting/demounting operation has been successful, in other words that the position of the stressed portions relative to the valve and/or TPMS sensor and the intensity of such stresses fall within the ranges defined as acceptable, may for example be that shown in FIG. 5, namely the addition to the report document of an icon 500 of circular shape, coloured in green for example and bearing the wording “OK”, positioned in the centre of the graphic representation of the wheel.

[0159] On the other hand, if the procedure has been executed incorrectly, said icon 500 could, for example, be coloured in red and not bear the wording “OK”.

[0160] Evidently, such graphic representations may be amplified at will by adding further explanatory messages of various kinds, in graphic, audio or text form, for the benefit of the operator.

[0161] As an alternative or in addition to the report document, the control unit 9 may be set up so that the data relating to the positions of the valve and/or TPMS sensor and stress values of the tire are sent to a remote computer system for storage and/or further processing and/or various uses.

[0162] As a general rule, the tire changer 1 of the present invention is capable of documenting the correctness of the execution of the maintenance operation, starting from a knowledge of the initial position (and if necessary the final position) of the TPMS sensor (and of the inflation valve if necessary) and if necessary the state of wear and/or the correct functionality of the wheel and/or its components (rim, valve, TPMS sensor, tire), from the tracing of the change in the angular positions of the valve and/or the TPMS sensor, using the rotation sensor 11, and from a knowledge of the angular position of the tensile stresses applied to the tire by the rim and/or tool, measured using the detector means 12, for example by monitoring the current draw of the electric motor.

[0163] If it is found, on completion of the procedure, that the position of the valve and/or the TPMS sensor has never come into contact with areas of the tire subjected to high stress, and that the values of such high stresses have never exceeded the predetermined acceptability threshold, it is reasonable to expect, given the professional practice described above in the wdk procedures and given that the wheel has not completed more than one full revolution, that the maintenance procedure has taken place correctly and that neither the valve nor the TPMS sensor nor the tire have been at risk of damage.

[0164] In any case, all the information collected in relation to the performance of the maintenance operations, and the corresponding reporting, when saved in a computer system such as a workshop management system, may be archived for future use and retrieved when necessary.

[0165] Such reporting may evidently be supplied to the customer for the purpose of certifying that the maintenance operation has taken place to a professional standard, as a tool for resolving any disputes, or for developing customer loyalty.

[0166] The operating procedures of the invention are illustrated briefly below.

[0167] The Operation of Demounting the Tire from the Rim

[0168] When the wheel 4 has been placed on the self-centring plate 6 and the rim has been gripped with the suitable clamps 60, the operator visually checks the position of the TPMS sensor on the physical wheel, and uses the touchscreen of the input/output device 10 to select the circular sector which, in the graphic representation of the wheel on the screen of the input/output device, approximately corresponds to that in which the inflation valve of the physical wheel is located.

[0169] In the case of TPMS sensors mounted at the position of the inflation valve, the position of the sensor corresponds to that of the valve. In the case of TPMS “strap” sensors, the position of the TPMS sensor is usually rotated through 180° relative to the position of the valve. In doubtful cases, since the TPMS sensor is not directly visible to the naked eye when the tire is mounted on the rim, before starting the demounting procedure, the operator, in order to be able to see the TPMS sensor directly, must disengage the tire from the wheel in order to detach the beads from the flanges of the rim and be able to verify the position of the TPMS sensor visually.

[0170] In any case, when the position of the TPMS sensor has been indicated by means of the input/output device 10, the control unit 9 can correlate the position of the TPMS sensor with the rotational position of the self-centring plate 6.

[0171] At this point, the operator will inform the control unit 9 that he intends to perform an operation of demounting the tire from the rim.

[0172] Having received this information, the control unit 9 calculates the distance between the circular section on the physical wheel corresponding to that selected by the operator on the input/output device and the position of the mounting/demounting tool.

[0173] If this distance is different from a predetermined distance, the control unit 9 commands the electric motor to put the self-centring plate (and therefore the wheel) into rotation, in order to move the TPMS sensor to a distance equivalent to the predetermined, or safety, distance.

[0174] At this point, the operator may commence the operation of demounting the tire from the rim, in the usual way and in complete safety.

[0175] With reference to FIG. 6, the direction of rotation of the wheel, indicated by the arrow, is clockwise. With respect to the position of the mounting/demounting tool 8, it is considered that, during the operation of demounting the tire from the rim, the TPMS sensor must initially be positioned, in order to operate safely, inside the arc indicated by the Greek letter α in the figure, that is to say an arc having an amplitude of approximately 15° or less.

[0176] In any case, according to the wdk procedures, it is considered that, in the initial position of the demounting procedure, the sensor must be located close to and upstream of the mounting/demounting tool 8, while the lever L (if present) must be located close to and downstream of the tool.

[0177] If the tire changer is provided with automatic mounting/demounting tools 8, or if there is no need to use a lever L during the demounting procedure, the initial position of the TPMS sensor may also be downstream of the tool and preferably still close to it, for example within an arc having an amplitude of approximately 15° or less, downstream of the tool.

[0178] In any case, the initial position of the TPMS sensor in FIG. 6 is indicated by T0. The arc indicated by the Greek letter β, illustrated in FIG. 6, is considered to be dangerous, and therefore, in order to avoid damaging the TPMS sensor, it is preferable for the sensor to be outside this arc at the start of the demounting operation.

[0179] During the demounting operation, the areas where the contact between the rim and tire develops the greatest stresses are usually located in the arc extending from about 120° to 270° relative to the position of the tool 8. For guidance, during the demounting procedure it is recorded that the intensity of such stresses reaches high values (indicated by MAX in FIG. 6) very rapidly between 120° and 180°, and then decreases progressively (the corresponding area of lower values of stress is indicated by MIN in FIG. 6).

[0180] In any case, if the location of the TPMS sensor is expected to be between eleven o'clock and one o'clock (relative to the midday position of the tool) at the start of the demounting operation, the position of the TPMS sensor is expected to be between four and five o'clock on completion of the demounting. In general, in the course of the demounting operation, and in the absence of any hazardous slippage between the rim and the tire, the wheel (and therefore the TPMS sensor) usually completes about half of a revolution. A possible final position of the TPMS sensor, illustrated in FIG. 6a, is indicated by T1. When the final position of the TPMS sensor is approximately that shown schematically in FIG. 6a, evidently without the wheel having completed a full revolution, it can usually be affirmed that there has been no significant slippage between the rim and the tire during the procedure, and therefore that the TPMS sensor has never been in any dangerous areas, that is to say the angular sections of the wheel where the stresses exerted by the rim on the tire bead are particularly high.

[0181] In such a case, it is impossible for the TPMS sensor to have been damaged by contact with the bead, and it may be verified that the demounting procedure has taken place according to the wdk procedures.

[0182] The Operation of Mounting the Tire on the Rim

[0183] When the rim 3 has been placed on the self-centring plate 6 and said rim has been gripped with the appropriate clamps 60, the operator visually checks the position of the TPMS sensor on the physical rim, and uses the touchscreen of the input/output device 10 to select the circular sector which, in the graphic representation of the wheel on the screen of the input/output device, approximately corresponds to that in which the TPMS sensor is located on the physical rim.

[0184] Thus the control unit 9 can correlate the position of the TPMS sensor with the rotational position of the self-centring plate 6.

[0185] At this point, the operator will inform the control unit 9 that he intends to perform an operation of mounting the tire on the rim.

[0186] Having received this information, the control unit 9 calculates the distance between the circular section on the physical rim corresponding to that selected by the operator on the input/output device and the position of the mounting/demounting tool.

[0187] If this distance is different from a predetermined distance, the control unit 9 commands the electric motor to put the self-centring plate (and therefore the rim) into rotation, in order to move the TPMS sensor.

[0188] With reference to FIG. 7, the direction of rotation of the wheel, indicated by the arrow, is clockwise. Regarding the position of the mounting/demounting tool 8, it is considered that, during the operation of mounting the tire from the rim, the TPMS sensor must initially be positioned inside the arc indicated by the Greek letter α, that is to say an arc having an amplitude of approximately 15-20° and located opposite the position of the mounting/demounting tool; for guidance (if the position of said tool is taken to be 0°), the arc α should be located between 160° and 180°, preferably between 165° and 180°. In any case, the TPMS sensor should be located, at the start of the mounting operation, between five o'clock and six o'clock relative to the midday position of the tool.

[0189] In FIG. 7, the initial position of the TPMS sensor is indicated by T0.

[0190] If the control unit 9 detects that the angular distance between the TPMS sensor and the mounting/demounting tool is different from the predetermined distance, and the TPMS sensor is therefore located within the arc identified by the Greek letter β, it will put the self-centring plate into rotation to impart a sufficient rotation to the wheel to place the TPMS sensor within the arc α.

[0191] At this point, the operator may commence the operation of mounting the tire on the rim, in the usual way and in complete safety.

[0192] During the mounting operation, the areas where the tire bead is subjected to the greatest stresses are usually located in the third and fourth quadrants of the wheel. Such stresses usually start at low values (indicated by MIN in FIG. 7) and increase progressively and without any abrupt changes to a peak (indicated by MAX in FIG. 7), and then fall to zero on completion of the mounting. It is evidently important that the TPMS sensor should not come to be located in such areas during the mounting of the tire.

[0193] In any case, if, as stated, the TPMS sensor is expected to be located between five o'clock and six o'clock (relative to the midday position of the tool) at the start of the mounting operation, then the position of the TPMS sensor is expected to be between approximately two and five o'clock on completion of the mounting.

[0194] In general, in the course of the mounting operation, and in the absence of any hazardous slippage between the rim and the tire, the wheel (and therefore the TPMS sensor) usually completes about three quarters of a revolution. A possible final position of the TPMS sensor, illustrated in FIG. 7a, is indicated by T1.

[0195] When this is the case, evidently without the wheel having completed a full revolution, it can usually be affirmed that there has been no significant slippage between the rim and the tire during the procedure, and therefore that the TPMS sensor has never passed through any dangerous areas, that is to say the angular sections of the wheel where the tire bead is subjected to high stresses.

[0196] If such a condition is present, it is impossible for the TPMS sensor to have been damaged by contact with the bead, and it may be verified that the mounting procedure has taken place according to the wdk procedures.

LIST OF REFERENCES

[0197] 1 Vehicle wheel maintenance apparatus [0198] 2 Tire [0199] 3 rim [0200] V inflation valve [0201] T TPMS sensor [0202] T0 initial position of TPMS sensor [0203] T1 final position of TPMS sensor [0204] 4 wheel [0205] MAX area of maximum tension [0206] MIN area of minimum tension [0207] 5 base [0208] A main axis of the wheel [0209] 6 rotary support [0210] 60 gripping clamps [0211] 7 column [0212] 8 mounting/demounting tool [0213] 9 control unit [0214] 10 input/output device [0215] L lever [0216] 11 rotation sensor [0217] 12 detector means [0218] 13 memory means associated with the control unit [0219] 14 computer-readable memory means [0220] 400 portions subject to high stress [0221] 500 indication of correct execution of the operation