Apparatus and method for mounting and removing tyres on and from respective wheel rims

Abstract

An apparatus for mounting and removing a tyre on and from a respective rim comprises: an element for moving a bead of the tyre in order to insert/remove the bead into/from a respective groove in the rim, the element comprising a tool connected to a respective supporting arm for moving the bead; a rotatable support for the rim, in such manner as to turn the rim and the tyre about a corresponding longitudinal axis of the rim; at least one sensor associated with the supporting arm for measuring the mechanical strain applied to the bead of the tyre when the latter is mounted on, and removed from, the rim.

Claims

1. An apparatus for mounting and removing a tyre on and from a respective rim, comprising: a column; at least a movement element for moving a bead of the tyre, having a tool connected to a respective power-driven arm supporting the tool, wherein the movement element is supported by the column; a rotatable support for supporting and moving the rim, rotatable in such manner as to turn the rim and the tyre about a corresponding longitudinal axis of the rim; at least one sensor associated with the arm supporting the tool for measuring mechanical strain applied to the bead of the tyre when the tyre bead is moved by the movement element during a rotation of the rim, wherein the arm includes a rod-shaped element having a first end connected to the column and a second end connected to the tool, and wherein said at least one sensor is coupled to said rod-shaped element, between the first and the second end.

2. The apparatus according to claim 1, wherein the tool is a tool for inserting/removing the bead into/from a respective groove in the rim, and wherein the at least one sensor is associated with the arm for measuring the mechanical strain applied to the bead of the tyre when the latter is mounted on, and removed from, the rim.

3. The apparatus according to claim 1, wherein the tool has a hook or a lever shaped in such a way that it can be interposed between the bead and the rim in order to clutch and extract the bead.

4. The apparatus according to claim 1, wherein the tool is a bead loosening tool in the form of a rotatable disc designed to be placed on a sidewall of the tyre in such a way as to press it towards an opposite sidewall, wherein the disc is supported by said power-driven arm.

5. The apparatus according to claim 1, wherein the at least one sensor comprises a plurality of extensometers located on an outside surface of the arm.

6. The apparatus according to claim 1, wherein the arm has a cross section in the form of a polygon with an even number of sides and therefore has an even number of respective faces, pairs of extensometers being associated with respective pairs of parallel faces of the arm.

7. The apparatus according to claim 6, wherein the arm comprises a first end, directed towards the rotatable support and associated with the tool, and a second end, opposite the first end, operatively connected to a supporting column, the sensor being interposed between said first and second ends.

8. The apparatus according to claim 1, wherein said at least one sensor is a force sensor.

9. The apparatus according to claim 1, comprising an electronic control unit connected to the at least one sensor in order to receive a signal representing the mechanical strain applied to the bead and measured by the at least one sensor, the electronic control unit being programmed to process the signal and provide a user of the apparatus with an indication as to the mechanical strain the bead is subjected to.

10. The apparatus according to claim 1, comprising an electronic control unit connected at least to the sensor in order to receive a signal representing the mechanical strain applied to the bead and measured by the at least one sensor, the electronic control unit being programmed to process the signal and drive the bead movement element and/or the rim rotatable support according to the data measured by the sensor.

11. A method for mounting and removing a tyre on and from a respective rim, comprising the following steps: positioning the rim and the tyre on a rotatable support; actuating a movement element supported by a column and having an arm for supporting a tool designed to interact with at least a portion of a bead of the tyre in such a way as to place said portion at a predetermined position relative to the rim, wherein the arm includes a rod-shaped element having a first end connected to the column and a second end connected to the tool; turning the rim and the tyre in such a way that the movement element slides over the bead in order to insert or extract the bead itself into or from a respective groove in the rim; measuring mechanical strain applied to the bead of the tyre at a zone of the bead that is operatively in contact with the movement element during tyre mounting and/or removal, using a sensor associated with (i) said rod-shaped element of the arm of the movement element, between the first and the second end, and/or (ii) an engagement tool engaged with a circular outside edge of the rim, through jaws that lock the rim edge there between during a rotation of the rim, in such a way that at least a portion of the tool is interposed between the edge and at least a portion of the tyre, while the rim and the tyre are turned in such a way that the movement element slides over the bead in order to insert the bead itself into the groove, wherein the engagement tool is provided with a portion for pushing the bead of the tyre towards an annular groove of the rim.

12. The method according to claim 11, wherein the mechanical strain applied to the tyre is measured during the entire duration of the step of turning the rim, in order to monitor the strain applied to the tyre bead as the bead is moved to the predetermined position relative to the rim.

13. The method according to claim 11, wherein measuring the mechanical strain applied to the tyre comprises the following sub-steps: sending a signal representing the mechanical strain to an electronic processing unit; controlling the step of inserting the bead and/or the step of turning the rim in such a way that the mechanical strain does not exceed a reference value, driving means for moving a bead movement element and/or rim supporting shaft, respectively, according to said signal.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) Further features and advantages of the invention are more apparent in the non-limiting description which follows of a preferred but non-exclusive embodiment of an apparatus and method for mounting and removing tires on and from respective wheel rims, as illustrated in the accompanying drawings, in which:

(2) FIG. 1 is a perspective view of an apparatus for mounting and removing tires on and from respective wheel rims;

(3) FIG. 2 is an enlarged perspective view of a portion of the apparatus of FIG. 1 showing the means for turning the wheel;

(4) FIG. 3 is an enlarged perspective view of another portion of the apparatus of FIG. 1 showing the means for turning the wheel;

(5) FIG. 4 is an enlarged perspective view of a detail of the portion of the apparatus of FIG. 1 relating to the means for turning the wheel, in a partly open view;

(6) FIG. 5 shows a wheel having applied to it a tool for engaging a rim edge and used in the apparatus of FIG. 1 during the mounting of the tire;

(7) FIG. 6 illustrates a tool like the one of FIG. 1 for engaging a rim edge, according to another embodiment.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

(8) With reference to the accompanying drawings, the numeral 1 denotes in its entirety an apparatus for mounting and removing tires 2 on and from respective wheel rims 3.

(9) The apparatus 1 comprises means 4 for supporting and moving a rim 3, designed to hold the rim 3 to the apparatus 1 and to drive it rotationally about its longitudinal axis.

(10) In light of this, the supporting and movement means 4 comprise a rim 3 rotation member 171 for turning the rim 3 and the tire 2 about said longitudinal axis.

(11) More in detail, the supporting and movement means 4 comprise a rotary shaft 213 extending (vertically in the example illustrated but horizontally in other possible embodiments) from a base 6 and operatively connected to the rotation member 171 housed in the base 6.

(12) At the top of the shaft 213 there extends a self-centering device 222 in the form of a plate 7 for coupling to a rim 3, designed to anchor the rim 3 (that is, the wheel) to the apparatus 1 and operatively connected to the motor 182 to rotate about an axis of extension of the shaft 213 itself.

(13) The base 6 consists of a frame 192 having a substantially box-like shape to contain the motor 182.

(14) With reference to FIG. 2, the rotation member 171 comprises a motor 182 connected to its rotary shaft 212 in order to drive it rotationally.

(15) Preferably, the motor 182 is movably coupled to the frame 192 so it can move relative to the latter; more specifically, it is mounted in a pendular manner relative to the frame 192.

(16) The rotation member 171 also comprises a supporting flange 202 equipped with a first portion 202a rigidly anchored to the frame 192 and a second portion 202b opposite the first and designed to support the motor 182 in oscillating manner.

(17) That way, the motor 182 can oscillate about a point of connection to the second portion 202b of the flange 202.

(18) With reference to FIG. 3, it should be noted that preferably the shaft 212 is kinematically coupled (for example by pulleys) to a geared motor; this geared motor (of per se known type) is connected to the shaft 213 to drive it rotationally about the longitudinal axis.

(19) According to the invention, the supporting and movement means 4 comprise (more specifically, the rotation member 171 comprises) a sensor 252 for measuring the mechanical strain applied to the tire 2 while the latter is being mounted on, and removed from, the rim 3.

(20) More specifically, the rim 3 supporting and movement means comprise the sensor 252, which is designed to measure the mechanical strain applied in forced reaction to the supporting and movement means 4 as a result of the mechanical stress the tire 2 bead 2a is subjected to during tire mounting and removal on and from the rim 3.

(21) According to a first aspect of the invention, the sensor 252 is associated with the motor 182 (or rather, to a casing of the motor) in order to measure in particular the tangential strain applied to the tire 2 bead 2a during tire mounting and removal on and from the rim 3.

(22) Preferably, the motor 182 is mounted in pendular manner to a frame 192 (or mounted in any other way that enables the motor 182 to oscillate with respect to the frame 192), the sensor 252 being associated with a casing of the motor 182 and with the frame 192 in order to measure the mechanical strain applied to the motor as a result of the mechanical stress the tire 2 bead 2a is subjected to during mounting/removal of the tire 2 on and from the rim 3.

(23) More specifically, the supporting means 4 comprise (that is, the rotation member 171 comprises) a flange 202 for supporting the motor 182. Preferably, the sensor 252 is associated with the flange 202.

(24) The flange 202 preferably has a first portion 202a rigidly associated with the frame 192 and a second portion 202b for supporting the motor 182, which supports the motor 182 in such a way that the motor can oscillate, the sensor 252 being interposed between the first portion 202a and the second portion 202b of the flange 202.

(25) Preferably, the sensor 252 is a load cell interposed between the first and the second portion of the flange 202 in order to measure the oscillating movements of the motor 182, corresponding to the strain applied tangentially to the bead 2a of the tire 2 by the movement element 9 interacting with the bead 2a during removal/mounting of the tire 2.

(26) Thus, the sensor 252 is operatively associated with a casing of the motor 182 and with the frame 192 to measure the strain applied to the motor as a result of the mechanical stress on the bead 2a of the tire 2 during mounting/removal of the tire 2 on/from the rim 3.

(27) In effect, the rotation imparted to the shaft 213 by the motor 182, causes tangential strain to be applied to the tire 2 due to the retaining action of the bead 2a. In other words, in the process of mounting/removing the tire 2, the rim 3 is turned and all the stresses on the tire 2 are transferred to the shaft 213 and thus also to the rotation member 171 as a whole (and to the motor 182 in particular).

(28) Consequently, as the rotation rim 3 and the respective tire 2 turn, the sensor 252 measures the oscillating movements of the motor 182 due to the mechanical strain applied tangentially to the bead 2a.

(29) For precisely measuring the movements of the motor 182, the sensor 252 is advantageously interposed between the first portion 202a and the second portion 202b of the flange 202. Preferably, the sensor 252 is a load cell (of per se known type and therefore not described in detail).

(30) According to another aspect of the invention, the sensor 252 is associated directly with the shaft 213 through a bush 232 associated with the frame 192 and within which the shaft 213 slides (see FIG. 4).

(31) It should be noted that the technical solution just described may be used alternatively, instead of the one described previously (where the sensor 252 is positioned between the motor 182 and the frame 192) or, advantageously, in combination with it.

(32) The bush 232 contains a series of bearings that slide on the rotary shaft 213. Preferably, the apparatus 1 comprises a plurality of sensors 252 operatively coupled to said bearings.

(33) Thus, through the bearings, the sensor 252 measures the forces and moments acting on the shaft 213 and corresponding to the strain on the tire 2 during mounting/removal of the tire 2 itself.

(34) The sensors 252 consist preferably of load cells and, more preferably, of multi-axis load cells.

(35) Rising from the base 6 there is a supporting column 8 on which means for moving the tire and systems for controlling the apparatus 1 are positioned.

(36) In particular, the column 8 supports at least an element 9 for moving a bead 2a of the tire 2.

(37) More specifically, the tire 2 has two beads 2a in the form of annular edges forming the ends of the tire 2.

(38) The movement element 9 operates between the tire 2 and the rim 3 in order to insert the bead 2a into an annular groove (not illustrated in the accompanying drawings) formed in a cylindrical lateral surface of the rim 3. This is the case when the tire 2 is mounted on the rim 3.

(39) It should be noted that the movement element 9 is also designed to move the bead 2a away from the rim and/or to hold it away from the same, that is, to place the bead 2a in an extracted position relative to (that is to say, away from) the edge 3a of the rim 3. This is the case when the tire 2 is removed from the rim 3.

(40) Looking in more detail, the movement element 9 comprises a conveniently power-driven supporting arm 10 extending substantially along a longitudinal axis parallel to the axis of the shaft 213 (vertical in the example illustrated) and positioned at a predetermined distance from the supporting means 4, on the opposite side with respect to the wheel operatively associated with the supporting means 4.

(41) The arm 10 supports a tool 11 designed to operate on the tire 2 by retaining a part of its bead 2a.

(42) As shown in the accompanying drawings, the tool 11 comprises a hook 12, or a lever 12 or any other element shaped in such a way that it can be interposed between the bead 2a and the rim 3 in order to clutch and extract the bead 2a (when removing) or press it (when mounting). (The element will hereinafter be referred to as lever 12, without thereby limiting the scope of the invention.)

(43) The lever 12 (that is, the tool) is operatively coupled to a respective movement element 13 that moves the lever 12 itself. That way, the lever 12 can be inserted between the tire 2 and the rim 3 and moved to retain a part of the bead 2a. In other words, the lever 12 acts as a gripper for holding a part of the bead 2a.

(44) Preferably, as better illustrated in FIG. 1, the column 8 also supports a bead loosening tool 14 in the form of a rotatable disc 15 designed to be placed on a sidewall (that is, on a lateral portion) of the tire 2 in such a way as to press it towards the opposite sidewall.

(45) The rotatable disc 15 is supported by a power-driven arm 16 designed to move the disc 15 to the required position. As the rim 3 and the respective tire rotate, the disc 15 enables the bead 2a to be pushed into an outer circular edge 3a of the respective rim 3. During tire removal, the bead loosener 14 is also designed to detach the bead 2a of the tire 2 from the respective annular groove in the rim 3.

(46) The apparatus 1 preferably also comprises an electronic control unit 29 (illustrated schematically in FIGS. 4 and 5).

(47) The electronic control unit 29 is connected to the sensor 252 for receiving the data measured by it.

(48) The electronic control unit 29 is programmed to receive and process the data relating to the mechanical strain applied to the bead 2a of the tire 2 during the latter's mounting on/removal from the rim 3.

(49) Preferably, the electronic processing unit is connected to indicating means adapted to provide the user with a warning signal, for example visual or audible, when the strain value exceeds a predetermined threshold.

(50) Preferably, the electronic unit 29 is programmed to control the bead 2a movement element 9 and/or the rim 3 supporting means 4 according to the data received from the sensor 252. That way, the action on the tire 2 is constantly monitored, preventing the bead 2a from being excessively deformed and thus avoiding damage to the tire 2 as a whole.

(51) In particular, the electronic unit 29 is connected to an actuator (not illustrated in the drawings because it is of known type) adapted to move the power-driven arm 10 and/or the lever movement element 13 to drive them according to the signal received from the sensor 252, so that the strain measured by the sensor 252 remains under a predetermined critical value (thanks to a feedback control well known in the field of automatic controls).

(52) Preferably, the electronic unit 29 is connected (in addition to or, alternatively, instead of the actuator) to the motor 182 used to rotationally drive the shaft 212, and hence the shaft 213, in order to drive it according to the signal received from the sensor 252, so that the strain measured by the sensor 252 remains under a predetermined critical value (thanks to a feedback control well known in the field of automatic controls).

(53) In use, for mounting the tire 2 on the rim 3, the rim 3 is first placed on the rotatable mounting means 4. Next, the tire 2 is placed on the rim 3 and a first bead 2a is inserted into the annular groove of the rim 3.

(54) At this point, the movement element 9 is used to engage a first portion of the lateral bead 2a and to bend it past the edge 3a of the rim 3 so as to move the portion closer to the annular groove.

(55) An engagement tool (not illustrated since it is of known type) can now also be coupled to the circular edge 3a of the rim 3 to hold the tire 2 bead 2a in place.

(56) That way, the rim 3 and the tire 2 coupled to it can then be turned, making the movement element 9 (in particular the lever 12) slide along the bead 2a. This rotational movement progressively forces the entire bead 2a into the annular groove of the rim 3.

(57) As the rim turns, the bead undergoes deformation and therefore the loads acting on the tire bead 2a are measured by the sensor 252 through the oscillation of the motor 182.

(58) In effect, the mechanical strain applied to the tire 2 in the zone of the bead 2a in contact with the lever 12 are transferred to the shaft 213 and constantly measured by the sensor 252.

(59) It should be noted that the sensor 252 measures the strain on the tire 2 during the entire step of turning the rim 3 while the bead 2a moves progressively into the annular groove.

(60) Thus, the sensor 252 sends to the electronic processing unit 29 a plurality of signals representing the mechanical strain. Advantageously, the unit 29 controls, according to these signals, the step of inserting the bead 2a and the step of turning the rim 3.

(61) This invention therefore also provides a method for mounting a tire 2 on a respective rim 3, comprising the following steps: positioning the rim 3 on rotatable supporting means 4; positioning the tire 2 on the rim 3; inserting, by means of a movement element 9, at least a first portion of a tire 2 bead 2a into an annular groove formed in a cylindrical lateral surface of the rim 3; turning the rim 3 and the bead 2a in such a way that the movement element 9 slides over the bead 2a in order to insert the bead 2a itself into the annular groove; measuring the mechanical strain applied to the bead 2a of the tire 2.

(62) Preferably, the mechanical strain applied to the tire 2 is measured by means of a measuring sensor 252 associated with the rotation member 171.

(63) Further, the mechanical strain applied to the tire 2 is measured during the entire duration of the step of turning the rim 3, in order to monitor the strain applied to the tire 2 bead 2a as the bead 2a is progressively inserted into the annular groove.

(64) Preferably, measuring the mechanical strain applied to the tire 2 comprises the following sub-steps: sending a signal representing the mechanical strain to an electronic processing unit 29; controlling the step of inserting the bead 2a and/or the step of turning the rim 3 in such a way that the mechanical strain does not exceed a reference value, driving means for moving a bead 2a movement element 9 and/or a rim 3 supporting shaft 213, respectively, according to said signal.

(65) This invention also provides a method for removing a tire 2 from a respective rim 3, comprising the following steps: positioning the rim 3 with the tire 2 on it on rotatable supporting means 4; extracting, by means of a movement element 9, at least a first portion of a tire 2 bead 2a from an annular groove formed in a cylindrical lateral surface of the rim 3; turning the rim 3 and the bead 2a in such a way that the movement element 9 slides over the bead 2a in order to extract the bead 2a itself from the annular groove; measuring the mechanical strain applied to the bead 2a of the tire 2.

(66) Preferably, the mechanical strain applied to the tire 2 is measured by means of a measuring sensor 252 associated with the rotation member 171.

(67) Further, the mechanical strain applied to the tire 2 is measured during the entire duration of the step of turning the rim 3, in order to monitor the strain applied to the tire 2 bead 2a as the bead 2a is progressively extracted from the annular groove.

(68) Preferably, measuring the mechanical strain applied to the tire 2 comprises the following sub-steps: sending a signal representing the mechanical strain to an electronic processing unit 29; controlling the step of extracting the bead 2a and/or the step of turning the rim 3 in such a way that the mechanical strain does not exceed a reference value, driving means for moving a bead 2a movement element 9 and/or a rim 3 supporting shaft 213, respectively, according to said signal.

(69) Advantageously, the sensor 252 directly associated with the bead 2a measures the loads applied to the tire 2 accurately and continuously.

(70) Indeed, the sensor 252 can measure the mechanical strain applied directly to the tire 2 bead 2a while it is being turned in order to mount it on, or extract it from, the rim 3. This advantage is possible thanks to the position of the sensor 252, which measures the tangential strain transferred to the motor 182.

(71) As a result, the information collected is complete and refers to the tangential strain the bead 2a of the tire 2 is subjected to.

(72) Further, the structure of the entire apparatus 1 and of the means for measuring the loads on the tire 2 are particularly simple, practical and economical.

(73) According to another aspect of this invention, a sensor 251 designed to measure the mechanical strain applied to the tire bead by the tool 11 is associated with the above mentioned bead 2a movement element 9.

(74) In light of this, the apparatus 1 (for mounting and/or removing the tire) comprises the sensor 251 (in turn preferably comprising a plurality of sensors, such as extensometers for example) coupled to the arm 10 of the movement element 9.

(75) In this case, extensometers coupled to the outside surface of the arm 10 are preferably used.

(76) Preferably, the sensors 251 (for example, extensometers) are positioned on the outside surface at equal angular intervals; more preferably, there are three extensometers equally spaced from each other.

(77) In light of this, the arm 10 preferably comprises a rod-shaped element whose cross section has the shape of a polygon (preferably regular) with at least three sides; more preferably, the polygon has an even number of sides; more preferably still, the polygon has at least two pairs of parallel sides.

(78) It should be noted that the sensors 251 might also be positioned on a portion of the arm 10 whose cross section has any shape, for example circular.

(79) It is stressed that the fact that the tool supporting arm is equipped with the sensors 251 means that it can advantageously be used on both a tire mounting machine and on a tire removing machine; in the example illustrated, the apparatus can be used to both mount and remove the tire.

(80) Thus, the method according to the invention also comprises the further step of measuring mechanical strain applied, when the movement element 9 operates on the tire 2 bead 2a, by a tool 11 of the movement element 9 to the tire 2 bead (2a), using a sensor 251 coupled to an arm 10 of the movement element 9.

(81) According to another aspect of this invention, the apparatus 1 also comprises an engagement tool 17 that can be associated with the outer circular edge 3a of the rim 3 so as to be interposed between the edge 3a and the bead 2a of the tire 2 when the tire 2 is being mounted.

(82) In light of this, the apparatus 1 comprises a sensor 25 associated with the engagement tool 17 designed to measure the mechanical strain applied by the engagement tool 17 to the bead 2a of the tire 2 while the latter is being mounted on the rim 3.

(83) Thus, the method according to the invention also comprises the following further steps: associating an engagement tool 17 with a circular outside edge 3a of the rim 3 in such a way that at least a portion of the engagement tool 17 is interposed between the edge 3a and at least a portion of the tire 2 when the tire 2 is being mounted; measuring the mechanical strain applied to the bead 2a of the tire 2 by the engagement tool 17, using a sensor applied to the engagement tool 17.

(84) Two types of engagement tool 17 are contemplated, advantageously applicable jointly to the rim 3 when the tire 2 is mounted.

(85) The first type of engagement tool 17 (illustrated in FIG. 5) comprises a main body 18 having a clamp that can be engaged with the edge 3a of the rim 3 in a zone where the bead 2a is operatively positioned at an annular groove in the rim, the sensor 25 being associated with the clamp.

(86) The second type of engagement tool 30 (illustrated in FIGS. 5 and 6) comprises an elastic element 31 having an arcuate profile and forming a cavity 32 that fits an arcuate portion of the edge 3a of the rim 3, the sensor 25 being coupled to a zone of the elastic element 31 that is operatively interposed between the bead 2a and the edge 3a of the rim 3, when the tool 30 is coupled to the rim 3.

(87) Preferably, the electronic processing unit 29 is connected to the sensors 25 and, where present, also to the sensors 251 and, where present, also to the sensors 252 described above.

(88) In light of this, the electronic processing unit 29 is programmed to receive signals from two or more sensors (any combination of the sensors 25, 251 and 252) to process the information captured by the sensors and derive the reference parameter values.

(89) These reference parameters are used to obtain an optimized representation of the mechanical strain applied to the bead during tire mounting and removal.

(90) Advantageously, the sensor 251 directly associated with the bead 2a measures the loads applied to the tire 2 accurately and continuously.

(91) Indeed, the sensor 251 can measure the mechanical strain applied directly to the tire 2 bead 2a while it is being deformed in order to mount it on, or extract it from, the rim 3. This advantage is possible thanks to the position of the extensometers 251a, which measure the strain on the arm 10 that may be bending, pulling, compressional and torsional strain.

(92) As consequence, the information gathered (detected) are particularly complete and are pertinent to axial stresses, radial stresses, tangential stresses to which the bead of tire is subjected.

(93) Further, the structure of the entire apparatus 1 and of the means for measuring the loads on the tire 2 are particularly simple, practical and economical.

(94) Another advantage of the invention is that it provides an apparatus and a method for mounting and removing tires that makes it possible to measure all types of mechanical strain applied to the tire bead (during both mounting and removal of the tire).

(95) This result is obtained also thanks to the presence of the sensors coupled to different parts of the apparatus.

(96) Thus, the invention contemplates the use of sensors 25 in the engagement tools 17 (also, two or more of these accessories, preferably of different types, that is to say, one equipped with a clamp and another equipped with an elastic element 31, may be used simultaneously).

(97) These engagement tools 17 equipped with pressure sensors 25 are particularly suitable for measuring radial strain (especially the engagement tool 17 with the elastic element 31) and axial strain especially the engagement tool 17 with the clamp).

(98) The invention also contemplates the use of sensors 251 associated with the arm 10 that supports the mounting/removing tool 11.

(99) The sensors 251 are particularly suitable for measuring the bending, pulling and compressional strain, as well as torsional strain applied to the arm.

(100) Therefore, the sensors 251 make it possible to obtain information about all the types of strain (axial, radial and tangential) from the measured strain values using appropriate calculations.

(101) The invention also contemplates the use of sensors 252 associated with the means 4 for supporting (and moving) the rim.

(102) The sensors 252 are particularly suitable for measuring the tangential and axial strain on the bead.

(103) In light of this, the integrated use of the different sensors 25, 251 and 252 is particularly advantageous.

(104) Hence, the present invention makes available an engagement tool 17 that can be associated with an outer circular edge 3a of a wheel rim 3 so as to be interposed between the edge 3a and a bead 2a of a tire 2 of the wheel in an apparatus 1 for mounting the tire on the respective wheel rim, said engagement tool 17 for engaging the edge 3a of the rim 3 comprises a sensor 25 designed to measure the mechanical strain applied to the tire 2 by the engagement tool 17 while the tire 2 is being mounted on the rim 3.

(105) Furthermore, the present invention makes available an apparatus 1 for mounting and removing a tire 2 on and from a respective rim 3, comprising: an element 9 for moving a bead 2a of the tire 2 in order to insert/remove the bead 2a into/from a respective groove in the rim 3, the element 9 comprising a tool 11 connected to a respective supporting arm 10 for moving the bead 2a; means 4 for supporting and moving the rim 3, rotatable in such manner as to turn the rim 3 and the tire 2 about a corresponding longitudinal axis of the rim 3; a sensor 251 associated with the supporting arm 10 for measuring the mechanical strain applied to the bead 2a of the tire 2 when the latter is mounted on, and removed from, the rim 3.