ITTO20130484A1 - ELECTRONIC DEVICE INVOLVABLE TO THE BODY OF A USER AND METHOD TO DETECT THE WEAR OF A FALL PROTECTION DEVICE - Google Patents

Description

DESCRIPTION

of the patent for industrial invention entitled:

â € œ ELECTRONIC DEVICE BINDING TO THE BODY OF A USER AND METHOD FOR DETECTING THE WEAR OF A FALL PROTECTION DEVICEâ €

The present invention relates to an electronic device that can be linked to a user and able to detect the wear of a fall protection device. In particular, the electronic device is designed to detect the wear of a fall protection device connected to the user, such as a rope, a harness (â € œharnessâ €), an anchor or a quickdraw. Furthermore, the present invention relates to a method for detecting the wear of a fall protection device.

As is known, in order to guarantee high safety standards for those who practice mountaineering activities, the need is felt to have devices that allow to accurately determine the state of wear (equivalent to damage) of safety devices. fall protection. For example, given any rope for mountaineering, the need is felt to know the state of wear of the rope, this state being influenced by the number and extent of falls to which the rope has been subjected during its own operational life. Similar considerations apply, for example, to harnesses.

To date, the wear of mountaineering equipment is generally estimated empirically, by visual inspection, carried out by expert personnel. However, this method of estimating wear implies the need to use particularly qualified personnel, and it is also qualitative in any case. In fact, the visual inspection does not allow in any way to precisely quantify the state of wear, but rather allows to obtain general indications.

The aim of the present invention is therefore to provide an electronic device, which at least partially solves the drawbacks of the known art.

According to the present invention, an electronic device and a method for detecting wear are provided, as defined in the attached claims.

For a better understanding of the invention, embodiments are now described, purely by way of non-limiting example and with reference to the attached drawings, in which:

Figure 1 shows a block diagram of an embodiment of the present electronic device;

- figure 2 schematically shows an electronic unit of the present electronic device, coupled to a harness;

- figure 3 symbolically shows a mountaineer, during a progression on a rocky wall;

Figure 4 shows a trend over time of a signal generated by an accelerometer of the present electronic device;

- figure 5 shows the trend of the maximum number of fall events that can be tolerated, according to the maximum force to which the mountaineering equipment is subjected during the fall events;

figure 6 shows a flow diagram of the operations carried out by the present electronic device;

figure 7 shows a block diagram of a further embodiment of the present electronic device; And

- figure 8 schematically shows a mobile phone in which the electronic unit shown in figure 2 is integrated.

Figure 1 shows an electronic device 1, which comprises a first and a second electronic unit 2, 4.

As shown in figure 2, the first electronic unit 2 is adapted to be tied to a harness 6, of a per se known type. The first electronic unit 2 can be permanently integrated into the harness 6, or it can be releasably coupled to the latter, for example by using Velcro. Furthermore, although in the following reference is made, without any loss of generality, to the case in which the first electronic unit 2 is tied to the harness 6, it is also possible to tie the first electronic unit 2 directly to the body of a generic user; for example, the first electronic unit 2 can be made integral, that is, it can be fixed to the body of a mountaineer by using an elastic band (not shown).

That said, the first electronic unit 2 comprises an accelerometer 8, a first processing unit 10, a battery 12, a memory 14, a luminous indicator 16 and a first communication stage 18.

The battery 12 is connected to the accelerometer 8, to the first processing unit 10, to the memory 14, to the luminous indicator 16 and to the first communication stage 18, so as to power them.

The first processing unit 10 is connected in a bidirectional way to the memory 14 and to the first communication stage 18, which is of the bidirectional type; moreover, the first processing unit 10 controls the luminous indicator 16. The first processing unit 10 is therefore capable of receiving and transmitting data through the first communication stage 18.

In greater detail, in the embodiment shown in figure 1, the accelerometer 8, per se known, is of the triaxial type, therefore it is suitable for generating an electrical signal of measured acceleration, which is indicative of the temporal trends of three components x, aye az, of the acceleration to which the same accelerometer is subject 8. The three components x, ay, az are orthogonal to each other; moreover, since the accelerometer 8 is integral with the first electronic unit 2, and therefore with the harness 6 and the rope 34, the latter and the user are subjected to the same acceleration to which the € ™ accelerometer 8.

More specifically, the accelerometer 8 is for example of the MEMS type and measures the relative acceleration of the accelerometer 8 itself, with respect to a body in free fall. The three components x, ay, az are therefore referred to a reference system in free fall.

The first processing unit 10 determines, on the basis of the measured electrical acceleration signal provided by the accelerometer 8, an acceleration modulus signal M_A (t), which is indicative of the modulus of the vector sum of the aforementioned three components x, ay, az. In the following this module is referred to as the acceleration module to which accelerometer 8 is subject, and is indicated with | a |.

The second electronic unit 4 comprises a second processing unit 20 and a second communication stage 22, electrically connected to each other. Furthermore, the second electronic unit 4 comprises a user interface 24, connected to the second processing unit 20.

The second communication stage 22 is of the bidirectional type and is suitable for communicating with the first communication stage 18. Furthermore, both the first and the second communication stage 18, 22 are preferably of the so-called wireless type (â € œwirelessâ €), although there are still possible embodiments in which they are suitable for allowing communications of the wired type (â € œwiredâ €).

In practice, according to the embodiment shown in Figure 1, the first and second processing units 10, 20 can exchange data, thanks to the interposition of the first and second communication stages 18, 22, each of which forms a corresponding transceiver.

That said, the first electronic unit 2 operates as a sort of black box, which detects and stores the falls to which harness 6 is subject, or more precisely the user of harness 6.

In particular, figure 3 shows an example of a situation that can commonly occur during mountaineering, and which involves the presence of a mountaineer (user) 30 and a rock wall (for example) 32.

Mountaineer 30 is wearing harness 6, has a mass m and is secured to the rock face 32, that is, it is connected to the latter by a rope 34 and an anchor point 36. The point of anchorage anchor 36 is for example formed by a so-called bolt, integral with the rock face 32, and by a so-called quickdraw, which is releasably coupled to the bolt; inside the quickdraw, the rope 34 can slide. Alternatively, and again purely by way of example, the anchor point 36 can be formed by a so-called fast protection, such as a â € œfriendâ €, to which the rope is suitably coupled.

In general, the anchor point 36 is connected to the rock wall 32 and is substantially fixed with respect to the latter, or in any case it is subject to limited displacements with respect to the rock wall 32. Furthermore, the rope 34 is coupled to the anchor point 36, not necessarily in such a way that at least one point of the rope 34 is fixed with respect to the anchor point 36. However, in the following it is assumed, for simplicity, that the rope 34 has a first end fixed to the anchor point 36 and a second extreme fixed to the harness 6 of the mountaineer 30, this hypothesis being very common in the field of studies relating to the dynamics of falls in the mountains and the related effects on the human body and equipment.

In practice, the string 34 has a length l, intended precisely as the length of the portion of the string extending between the aforementioned first and second ends. Therefore, during the progression, the mountaineer 30 is at most at a distance equal to l from the anchor point 36. In the following it is assumed that this distance is measured along a vertical axis parallel to the direction of gravity and passing through the point of anchor 36, that is, it is assumed that the mountaineer 30 is at a point A, which is placed at a height equal to l with respect to the anchor point 36, the rope 34 being completely stretched between its first and second extreme. It is also assumed that the aforementioned distances are measured along the aforementioned vertical axis and are therefore comparable to corresponding heights. This situation commonly occurs when the rocky wall 32 is substantially vertical.

In the event of a fall, it is assumed that the mountaineer 30 initially falls in free fall, up to a point B, with respect to which the anchor point 36 is at a height equal to l. The point B is therefore from the point A a distance h equal to 2 * l. Subsequently, due to the deformation of the rope 34, the mountaineer 30 continues his fall to a point C, below the point B and distant from the latter a distance equal to d. In practice, the fall stops at point C, where the mountaineer has zero speed; moreover, d represents the maximum deformation to which the chord 34 is subjected.

From a quantitative point of view, it can be shown that, thanks to the conservation of energy, and in the case in which the load-deformation characteristic of the string 34 is linear, the relation holds:

mg (h + d) = kd <2> / 2 (1)

where k = E * A / l, where E is equal to the Young modulus of string 34 and A is equal to the area of the section of string 34.

Therefore, indicating with F the force to which the rope 34 is subject, and therefore also the harness 6 and the mountaineer 30, in general it is equal to k * x, where x is the deformation to which the rope 34. Since, when the mountaineer 30 is at point C, the deformation of the rope 34 assumes the maximum value, the force F to which the rope 34 is subject is also maximum and is equal to the product k * d. Therefore, the equation holds:

F 2

maxâˆ'2mgFmaxâˆ'2 mgkh = 0 (2)

from which we obtain that the maximum value Fmax of the force F to which string 34 is subject is equal to:

Fmax = mg [1+ 1 + 2fcEA / (mg)] (3)

where fc = h / l and is also known as the fall factor.

It follows that the maximum acceleration to which the mountaineer 30 is subjected, and therefore the maximum value amax of the aforementioned acceleration module | a |, is equal to:

amax = g [1+ 1 + 2fcEA / (mg)] (4)

In the case of the drop described above, the aforementioned acceleration modulus signal M_A (t) over time has a trend of the type shown in Figure 4.

Initially, in an instant t0 in which the mountaineer 30 is not yet falling, but is stationary with respect to the rock face 32, the acceleration modulus signal M_A (t) is equal to a value g_r, which indicates that the acceleration module | a | It is equal to the acceleration of gravity g.

Assuming that in a subsequent instant t1 the mountaineer 30 loses his grip and begins to fall in free fall, the value of the acceleration modulus signal M_A (t) decreases until it assumes, in a subsequent instant t2, a value a0_r, the which corresponds to a null value of the acceleration module | a |.

The acceleration modulo signal M_A (t) remains equal to the value a0_r, as long as the mountaineer 30 does not reach the aforementioned point B. Assuming that the mountaineer is in point B at an instant t3, after that instant t3 the chord 34 begins to deform. Consequently, the acceleration modulus signal M_A (t) increases until it assumes, in a subsequent instant t4, a maximum value amax_r, which indicates that the acceleration modulus | a | assumes a corresponding maximum value amax. In practice, in the time interval between the instants t1 and t3, the mountaineer 30 is in free fall; moreover, at instant t4 the mountaineer is at point C and the fall is over.

Subsequently at instant t4, mountaineer 30 is substantially subject to damped rebounds. Therefore, the acceleration modulo signal M_A (t) decreases until it assumes the value a0_r again, at a subsequent instant t5. Furthermore, the acceleration modulo signal M_A (t) remains equal to the value a0_r until a subsequent instant t6.

Subsequently at the instant t6, the acceleration modulus signal M_A (t) increases until it assumes a first relative maximum value arel1_r, at a subsequent instant t7. The first relative maximum value arel1_r is less than the maximum value amax_red indicates that the acceleration modulus | a | It is equal to a corresponding first relative maximum value arel1, lower than the maximum value amax.

Subsequently to the instant t7, the acceleration modulus signal M_A (t) decreases until an instant t8, in which it assumes a first residual value alow1_r, higher than the value a0_red lower than the value g_r. Thereafter, the acceleration modulo signal M_A (t) remains equal to the value alow1_r until an instant t9.

Subsequently at the instant t9, the acceleration modulus signal M_A (t) increases until it assumes a second relative maximum value arel2_r, at a subsequent instant t10. The second relative maximum value arel2_r is lower than the first relative maximum value arel1_red indicates that the acceleration modulus | a | It is equal to a corresponding second relative maximum value arel2.

Finally, after the instant t10, the acceleration modulus signal M_A (t) decreases until an instant t11, in which it assumes a second residual value alow2_r, this last value being equal to the value g_r. In practice, at the instant t11, the mountaineer 30 finds himself, in the hypothesis of not considering dissipative phenomena, in point C, where he subsequently remains, in the absence of further actions. Mountaineer 30 is therefore now immobile with respect to the rock face 32.

Given the time course of the acceleration module signal M_A (t), the first processing unit 10 can determine the corresponding values assumed over time by the acceleration module | a |, which, inside the ™ time interval between instants t1 and t11, has an absolute maximum, having a value equal to the aforementioned maximum value amax. The first processing unit 10 determines the maximum value amax of the acceleration module | a | to which the first electronic unit 2 is subject. Furthermore, the first processing unit 10 determines the maximum value Fmax of the force to which the rope 34, the harness 6 and the mountaineer 30 are subject, multiplying the maximum value amax of the modulus of the € ™ acceleration | a | for the mass m of the mountaineer 30.

Purely by way of example, the value of the mass m of the mountaineer 30 can be stored in the memory 14, in a way known per se. For example, the mass value m can be set through the user interface 24, which, in a per se known way, allows to acquire a signal indicative of the mass itself. Subsequently, the signal indicative of the mass is notified by the second processing unit 20 to the first processing unit 10, which stores the value of the mass m in the memory 14.

In addition, for each fall event, the first processing unit 10 increments a counter, initially set to zero, by one unit. The counter can be stored in memory 14.

In order to detect each fall event, the first processing unit 10 detects the presence of an absolute maximum of the acceleration module | a |, which has a higher value than the gravity acceleration g and falls inside of a time interval between two successive time periods in which the acceleration module | a | It is equal to the acceleration of gravity g. Note that the aforementioned maximum value amax of the acceleration modulus | a | It is absolute limited to the time interval between the two successive time periods in which the acceleration module | a | It is equal to the acceleration of gravity g.

Eventually, the first processing unit 10 can previously filter the acceleration module signal M_A (t), as well as implement a mechanism for comparing the maximum value amax determined by it with a predetermined acceleration threshold, and detect the fall event only if the acceleration threshold is exceeded. The counter is therefore only incremented if the acceleration threshold is exceeded.

In practice, the first processing unit 10 detects each fall event and associates the corresponding maximum value Fmax of the force to which the string 34 is subject, as determined by it. Furthermore, the first processing unit 10 stores in memory 14 each fall event and the maximum value Fmax associated with the fall event, which is also referred to as the maximum force Fmax of the fall event.

The first processing unit 10 also checks, at each fall event, whether a critical wear threshold of the rope 34 has been exceeded, on the basis of the maximum force Fmax relating to the fall event, as well as on the basis of the maximum forces Fmax relating to any previous fall events.

To this end, a critical chord curve nc (Fmax) is stored inside memory 14, an example of which is shown in figure 5. The critical chord curve nc (Fmax) is stored in memory 14; in particular, the critical chord curve nc (Fmax) is set through the user interface 24 and is subsequently notified by the second processing unit 20 to the first processing unit 10, which stores it in the memory 14.

The critical chord curve nc (Fmax) is of discrete type, it is a function of the physical characteristics of chord 34 and indicates, for a predetermined number of reference values (shown in Figure 5 on the abscissa axis), a corresponding maximum number of falls nc. In particular, given a reference value, the corresponding maximum number of falls nc indicates the maximum number of falls with maximum force Fmax equal to this reference value that the rope 34 can withstand, before assuming a state of dangerous wear.

As shown in Figure 6, in which the operations for detecting each fall event are indicated by 90, at each fall the first processing unit 10 determines (block 100) the corresponding maximum force Fmax, and subsequently determines (block 102), on the basis of the critical chord curve nc (Fmax), the corresponding reference value that is closest to the determined maximum force Fmax.

Subsequently, the first processing unit 10 determines (block 104), again on the basis of the critical chord curve nc (Fmax), the maximum number of falls ncc which corresponds to the determined reference value; in the following it is assumed, for example, that this corresponding maximum number of falls is equal to X.

Subsequently, the first processing unit 10 increases (block 106) by an amount equal to 1 / X a damage indicator, which is stored in memory 14 and was originally initialized to zero.

Finally, the first processing unit 10 compares (block 108) the damage indicator with a rope safety threshold, for example equal to one.

If the damage indicator is below the rope safety threshold (NO output of block 108), it means that rope 34 can still be used safely. Therefore, the first processing unit 10 keeps the luminous indicator 16 off (block 110).

Conversely, if the damage indicator is higher than the rope safety threshold (YES output of block 108), it means that the rope 34 has reached a critical wear state. In this case, the first processing unit 10 activates (block 112) the luminous indicator 16, so as to signal to the mountaineer 30 that the state of wear of the rope 34 is such as to discourage further use of the same.

As previously mentioned, although the previous description makes explicit reference to the wear of the string 34, the first processing unit 10 can also detect, alternatively or in addition to what has been explained above, the achievement of a critical wear state of the material mountaineering different from rope 34, such as harness 6. For this purpose, instead of the critical rope curve nc (Fmax), a critical harness curve (not shown) is used, which is a function of the characteristics of the harness 6 and indicates, for each reference value, the corresponding maximum number of falls that the harness 6 can withstand, before assuming a state of dangerous wear. For example, the harness critical curve can be obtained starting from the critical rope curve nc (Fmax), adding a constant, not necessarily positive, to the latter.

Similarly, it is also possible that the first processing unit 10 detects, alternatively or in addition to what has been previously explained, the achievement of a critical wear state of the material such as for example a transmission, or an anchor, such as for example the anchor point 36, through the use of corresponding critical curves.

It is also possible that the first processing unit 10 determines further quantities, such as the distance h between point A and point B (figure 3), on the basis of the equation h = 1/2 * g * tc <2>, in which tcà is the duration of the time interval between the instants t1 and t3.

In addition, the first processing unit 10 can determine one or more of the following quantities: an index of damage suffered by the mountaineer's body, a quantity indicative of the mountaineer's energy expenditure during the progression, one or more quantities indicative of the Evolution of the mountaineer's posture during the progression, as well as one or more quantities indicative of the movements carried out by the mountaineer. For this purpose, the first electronic unit 2 can comprise, as shown in Figure 7, a gyroscope 40 and a localization module 42, both connected to the first processing unit 10, as well as to the battery 12 (the latter connections not being shown) . The location module 42 is for example of the type of the global positioning system (â € œGlobal Positioning Systemâ €, GPS). In this way, the first processing unit 10 can determine a path tracking signal, in terms of position and altitude.

As shown again in figure 7, the first electronic unit 2 can also comprise a transmitter 44 of the type Avalanche Searching Device (ARTVA), connected to the battery 12 and to the first processing unit 10. The transmitter 44 is of the type that can be activated by the Mountaineer 30, or, preferably, from the first processing unit 10, following the detection by the latter of a fall event, followed by a period of time of predefined duration, in which no movements of the Mountaineer 30. In this way, the activation of the transmitter 44 can take place even if the mountaineer 30 is unconscious.

Although not shown, it is also possible that the first electronic unit 2 includes a magnetometer, which acts as a compass, and / or a pressure sensor, which acts as an altimeter.

According to a different embodiment, it is also possible that at least part of the operations performed by the first processing unit 10 are carried out by the second processing unit 10. In this case, it is for example possible that the measured electrical acceleration signal supplied from the accelerometer 8 is transmitted to the second processing unit 20, which is responsible for generating the acceleration module signal M_A (t) and for the subsequent processing. Similarly, also the signals coming from the gyroscope 40 and / or from the localization module 42 can be transmitted to the second processing unit 20, possibly after having been memorized inside the memory 14.

According to a still different embodiment, shown in Figure 8, the first electronic unit 2 can be integrated inside a cellular telephone 50 of a known type. To this end, since the mobile phone 50 has its own battery, its own processing unit, its own memory and a screen that can be used as a light indicator, it can be stored in the memory of the mobile phone 50 a program which, when executed, allows the processing unit of the mobile phone 50 to perform the operations described above, on the basis of the signals coming from the accelerometer and from other sensors possibly present in the mobile phone 50.

In other words, it is possible that the accelerometer 8 and the first processing unit 10 form a mobile phone 50, that is, they are integrated within the latter. Furthermore, the value of the mass of the mountaineer can be set using the keypad of the mobile phone 50, in which case the second electronic unit 4 may be absent, as well as the first communication stage 18.

The advantages that the present electronic device allows to obtain clearly emerge from the previous description. In particular, it allows to quantitatively determine the reaching of a state of critical wear by a fall protection device, such as to advise against continuing to use it.

Finally, it is evident that modifications and variations can be made to the present electronic device, without thereby departing from the scope of the present invention, defined by the attached claims.

For example, the accelerometer can be of the uniaxial type, in which case it is advisable for it to be constrained to the mountaineer in such a way that its axis is parallel to the direction of the fall.

There are also possible embodiments in which the relationship between the acceleration modulus signal M_A (t) and the acceleration modulus to which the accelerometer is subject is of a different type than described.

In place of or as an alternative to the luminous indicator 16, a different type of indicator may be present, such as an acoustic indicator.

Finally, although explicit reference has been made to the mountaineering field, this electronic device can also be used, for example, in the field of acrobatic work or shipbuilding, that is, in any field in which personnel may incur falls .

Claims (14)

CLAIMS 1. Electronic device suitable for detecting the wear of a fall protection device, comprising a first electronic unit (2) which can be linked to a user physically connected to said equipment, said first electronic unit including an accelerometer (8) capable of generating a electrical acceleration signal (M_A (t)) indicative of an acceleration to which the first electronic unit is subject; said electronic device further comprising a processing stage (10) configured to detect, on the basis of the electrical acceleration signal, fall events of the first electronic unit, the processing stage being further configured to determine, for each fall event, a corresponding maximum force value (Fmax) indicative of the maximum force to which the first electronic unit is subjected during the fall, based on the electrical acceleration signal; said processing stage being also configured to check, at each fall event, whether a critical wear threshold of said fall protection device has been exceeded, on the basis of the corresponding maximum force value. 2. Electronic device according to claim 1, in which the processing stage (10) is configured to update, at each fall, the value of a quantity indicative of the wear of said fall protection device, on the basis of the corresponding value of maximum force (Fmax), and to compare the updated value of said quantity with a wear threshold value indicative of said critical wear threshold. 3. Electronic device according to claim 2, further comprising a memory (14) configured to store a critical curve (nc (Fmax)), which is a function of at least one physical characteristic of said fall protection device and correlates a number of force reference values with corresponding maximum numbers of falls; and in which the processing stage (10) is configured to update the value of said quantity also on the basis of said critical curve. 4. Electronic device according to claim 3, in which the processing stage (10) is configured to detect whether the critical wear threshold of a harness (6) worn by the user (30) has been exceeded, or of a rope (34) mechanically coupled to said harness, or to an anchor point (36) to which the user (30) is connected. 5. Electronic device according to any one of the preceding claims, in which the processing stage (10) is configured to determine, for each detected fall event, the maximum value (amax) of the acceleration module to which the first electronic unit (2) during the fall, said maximum force value (Fmax) being a function of said maximum value of the acceleration module and the user mass (30). Electronic device according to any one of the preceding claims, wherein the first electronic unit (2) includes the processing stage (10), which is electrically connected to the accelerometer (8). 7. Electronic device according to claim 6, further comprising acquisition means (24) of a signal indicative of the mass of the user (30), said acquisition means being coupled to the processing stage (10). 8. Electronic device according to claim 7, further comprising a second electronic unit (4) configured to communicate with the first electronic unit (2) and including said acquisition means (24). Electronic device according to any one of the preceding claims, wherein the first electronic unit (2) comprises an optical and / or acoustic signaling device (16), the processing stage (10) being configured to activate said control device warning in case of exceeding of said critical wear threshold of the fall protection device. Electronic device according to any one of the preceding claims, wherein said accelerometer (8) and said processing stage (10) form a cellular telephone (50). 11. Method for detecting the wear of a fall protection device, comprising the steps of: - generating (90) an electrical acceleration signal (M_A (t)) indicative of an acceleration to which a user (30) is physically connected to said fall protection device; - detect (90), on the basis of the electrical acceleration signal, user fall events; - determine (100), for each fall event, a corresponding maximum force value (Fmax) indicative of the maximum force to which the user is subjected during the fall, on the basis of the electrical acceleration signal; And - check (108), at each fall event, if a critical wear threshold of said fall protection device has been exceeded, on the basis of the corresponding maximum force value. Method according to claim 11, further comprising the steps of: - update (106), at each fall, the value of a quantity indicative of the wear of said fall protection device; And - comparing (108), at each fall, the updated value of said quantity with a wear threshold value indicative of said critical wear threshold. 13. Method according to claim 12, further comprising the step of storing a critical curve (nc (Fmax)), which is a function of the physical characteristics of said fall protection device and correlates a number of reference force values with corresponding maximum numbers of falls; and in which said updating step (106) comprises updating said value of said quantity also on the basis of said critical curve. 14. Method according to claim 13, further comprising the step of detecting whether the critical wear threshold of a harness (6) worn by the user (30), or of a rope (34) mechanically coupled to said harness, or an anchor point (36) to which the user is connected (30).