Patent Abstract:
The invention concerns a device for tensioning belts or chains comprising a fixed support ( 4 ), an equipment ( 2 ) mobile relative to the fixed support ( 4 ) and designed to be in contact with the belt or the chain, and an actuator ( 14 ) designed to exert a permanent tensioning force between the mobile equipment and the fixed support. The device further comprises an assembly sensing ( 16, 28 ) parameters of angular displacement of the mobile equipment relative to the fixed support.

Full Description:
BACKGROUND OF THE INVENTION  
       [0001]     1. Field of the Invention  
         [0002]     The present invention generally relates to a belt-tensioning or a chain-tensioning device designed to ensure a suitable tension of a belt or chain. In particular, embodiments relate to systems and methods for ensuring a suitable tension of a belt or chain in a tension device in an automotive vehicle.  
         [0003]     2. Brief Description of the Related Art  
         [0004]     A tensioning device generally comprises a fixed bracket and a moving part, in the form of a cam or a swivel arm, mounted with rotational capability on the fixed bracket. A pulley is mounted in idle arrangement on the moving part by means of a rolling bearing and is intended to be brought into contact with the belt. A spring exerts a tension force between the bracket and the moving part, causing the pulley to make contact with the belt with a suitable belt tension. The moving part is mounted with adjustment capability on the bracket so as to be able to adjust the tension force of the belt, as described in FR 2 624 577 and FR 2 744 506, which describe tensioning devices.  
         [0005]     A belt-tensioning device has to be adjusted in order to maintain the tension of the belt within a certain tolerance range. Wear of the belt or the dimensional variations of the belt caused, for example, by temperature variations, may also require device adjustments to maintain tension. The tension applied in the belt by the tensioning device is adjusted in an assembly stage with the aid of visual reference marks. The tension of the belt is checked in the course of maintenance operations.  
         [0006]     The failure of a belt or of a tensioning device, can cause a stoppage or failure of a mechanical device connected to the belt and can impair the operating reliability of a mechanical device. A failure of a timing belt of a heat engine of an automotive vehicle can instantaneously cause serious damage to said engine.  
         [0007]     Tensioning devices of the type described above do not prevent failure of the belt or of the tensioning device. The imminence of a belt or tensioning device failure is difficult to predict and can happen suddenly and unexpectedly.  
       SUMMARY OF THE INVENTION  
       [0008]     In some embodiments, the system may include a belt-tensioning or chain-tensioning device by which the belt or chain tension may be easily and rapidly adjusted. The system may also include a belt-tensioning or a chain-tensioning device that may constantly monitor the tension of the belt, the wear of the belt and the correct functioning of the tensioning device. In certain embodiments, a belt failure or a failure of the belt-tensioning or chain-tensioning device may be anticipated.  
         [0009]     In one embodiment, a belt- or a chain-tensioning device may include a fixed bracket, a moving element, and/or an actuator. A moving element may move relative to the fixed bracket. A moving element may be in contact with the belt or the chain. An actuator may exert a permanent tension force between the moving element and the fixed bracket. The device may additionally include a sensor unit. A sensor unit may monitor movement parameters of the moving element relative to the fixed bracket.  
         [0010]     During use, movement parameters of the moving element relative to the fixed bracket may have characteristics of movement, variation of movement, frequency and amplitude of oscillation. These characteristics of the movement parameters are linked to the tensioning device and to the belt or the chain. By analyzing the movement parameters, it may be possible to detect the appearance of signals which are characteristic of faults or wear in the tensioning device and in the belt or chain. From the detected signal, the origin of this signal may be precisely determined.  
         [0011]     The sensor unit for the movement parameters of the moving element relative to the fixed bracket may be a sensor unit for angular displacement parameters. In an embodiment, the moving element may be rotation-mounted relative to the fixed bracket. An actuator may be arranged to exert a moment between the moving element and the fixed bracket.  
         [0012]     In one embodiment, the tensioning device includes a coder element positioned on a working cam of a tensioning roller or on a pivot bearing for an arm. The coder element may be able to rotate past a sensor coupled to the fixed bracket.  
         [0013]     In one embodiment, the moving element includes a pulley mounted in idle arrangement on the moving element. It may be desirable for the pulley to come into contact with the belt or the chain.  
         [0014]     In some embodiments, the tension of a belt or chain may be monitored. A tension force may be exerted between a fixed bracket and a moving element relative to the fixed bracket. A moving element may be in contact with the belt or the chain. Parameters of angular displacement of the moving element relative to the fixed bracket may be measured. In one embodiment, an angular displacement, an angular displacement velocity, a frequency and/or an amplitude of angular displacement of the moving element rotation-mounted relative to the fixed bracket may be measured.  
         [0015]     A record of failure of the belt or of the tension device may be a function of mean angular displacement thresholds. The threshold values of mean angular displacement may be values for which it is known to be worth proceeding to examine the tensioning device, the belt or the chain. Several thresholds may be used. In an embodiment, one threshold may be an alarm threshold for conducting a maintenance operation and one threshold may be a danger threshold by which a tear which is damageable by a stoppage of the mechanical unit using the belt may be anticipated.  
         [0016]     A record of failure of the belt or of the tension device may be a function of the frequency or amplitude of oscillation about a mean angular displacement value. By examining the frequency of the amplitude of oscillation of measuring signals for angular displacement, it may be possible to detect and characterize faults which might lead to a failure of the belt or of a tensioning device. A record of failure may be a function of thresholds of amplitude of oscillation or of frequency of oscillation about a mean angular displacement value.  
         [0017]     In some embodiments, the system may include a microprocessor with a CPU and a memory. A memory may be coupled to the CPU. A memory may include executable program instructions, such as a computer program. A computer program include modules for implementing a process for monitoring the tension of a belt tensioned by means of a tensioning device. The tensioning device may include a fixed bracket, a moving element relative to the fixed bracket, and an actuator that may exert a permanent tension force between the moving element and the fixed bracket. The computer program may include a module for receiving signals corresponding to parameters of angular displacement of the moving element relative to the fixed bracket, and a module for processing received signals. The module for processing received signals may furnishing a belt-tension record or a failure record on the basis of a movement value, a movement velocity value, and a frequency and amplitude of oscillation value.  
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0018]     Features and advantages of the methods and apparatus of the present invention will be more fully appreciated by reference to the following detailed description of presently preferred but nonetheless illustrative embodiments in accordance with the present invention when taken in conjunction with the accompanying drawings in which:  
         [0019]      FIG. 1  illustrates a cross-sectional view of an embodiment of a tensioning device;  
         [0020]      FIG. 2  illustrates a cross-sectional view of an embodiment of a tensioning device;  
         [0021]      FIG. 3  illustrates a plot of signals measured by an embodiment of a sensor unit positioned on a tensioning device;  
         [0022]      FIG. 4  illustrates an angle measurement determined by an embodiment of a sensor unit for rotation parameters positioned on a pivoting tensioning device;  
         [0023]      FIG. 5  illustrates a top view of an embodiment of a device.  
         [0024]      FIG. 6  illustrates a side view of an embodiment of a tensioning device; and  
         [0025]      FIG. 7  illustrates a side view of an embodiment of a tensioning device.  
     
    
     DETAILED DESCRIPTION OF EMBODIMENTS  
       [0026]     An embodiment of a tensioning device is depicted in  FIG. 1 . A tensioning device may include an adjusting cam  1  and a moving element. The moving element may include a working cam  2  mounted with rotational capability on the adjusting cam  1  by a tubular bushing  3  of a fixed bracket  4 . The tubular bushing  3  forms a plain bearing.  
         [0027]     An adjusting cam  1  may be fixed on a block  5  by means of a screw  6 . The adjusting cam  1  may pivot relative to the block  5  when the screw  6  is loosened. Fastening the screw  6  may immobilize the cam  1 .  
         [0028]     The bracket  4  may include a cylindrical metal insert  7  positioned between the cam  1  and the tubular bushing  3 . The metal insert  7  and the tubular bushing  3  are joined together by any appropriate means including, but not limited to, molding the tubular bushing  3  by casting the tubular bushing on the metal insert  7 . The bracket  4  may include a plate forming a substantially flat base  8 . The plate may attach perpendicularly to the tubular bushing  3  and bear upon the block  5  by means of the metal insert  7 . The base  8  may include a radially projecting tongue  9 . A blocking pin  10  may project, from a free end of the tongue  9 , axially into a corresponding opening  11  in the block  5 . The tongue  9  also may include at its free end a reference notch  12 .  
         [0029]     The bracket  4  may include a tubular axial portion  13  extending from a zone of greater diameter of the base  8 . The tubular axial portion  13  may surround the tubular bushing  3 .  
         [0030]     A sensor  16  may be positioned in the free end of the tubular axial portion  13 . The sensor  16  may be flush with the outer surface of tubular axial portion  13 . A connecting portion  17 , situated proximate to the sensor  16 , may extend in radial projection from the axial portion  13 . The connecting portion  17  may include linking means, diagrammatized by dotted lines, between the sensor  16  and a wire link  18  leaving the connecting portion  17 . The free end of the wire link  18  may include a connecting plug  19  with three pins  20   a,    20   b,    20   c.  The plug  19  may include a processing unit  21  represented by dotted lines.  
         [0031]     The working cam  2  may include a bore  22  mounted such that the bore slides rotationally on the tubular bushing  3  of the bracket  4 . The working cam  2  may include, at an end opposite to the base plate  8  of the bracket  4 , a cylindrical outer surface  23  of revolution about a different axis than the main axis of the bushing  3 . A pulley  24  may be rotation-mounted on the cylindrical surface  23  of the working cam  2  by means of a rolling bearing  25 .  
         [0032]     The cylindrical surface  23  may be limited axially by a shoulder  23   a  serving as an axial support for the rolling bearing  25 . A radial wall  26  may extend radially outward, may be adjacent to the shoulder  23   a,  and may be situated at a distance from the end of the working cam  2  on the side of the base plate  8 . The free edge of the radial wall  26  may be positioned axially proximate to the free end of the axial wall  13  of the bracket  4 .  
         [0033]     A tubular skirt  27  may extend axially from the zone of greater diameter of the radial wall  26  and may radially surround the free end of the axial portion  13 . The tubular skirt  27  may include a coder ring  28 . The coder ring  28  may lay flush with the inner surface  27   a  of the tubular skirt  27 . The coder ring  28  may face the sensor  16  positioned in the cylindrical axial portion  13 . A projection  29  extend radially from the outer surface of the skirt  27  to serve as a visual reference mark corresponding to the notch  12  in the tongue  9 .  
         [0034]     The coder ring  28  may be an optical-type coder ring. The coder ring  28  may include, but is not limited to, an alternation of opaque parts and reflective parts or a multipolar magnetic ring. The sensor  16  may be, but is not limited to, an optical sensor, a Hall-effect sensor, or a passive sensor in the form of a winding integrated in a flux concentrator cooperating by means of teeth with a multipolar magnetic ring.  
         [0035]     The rolling bearing  25  may include an inner raceway  30 , an outer raceway  31 , rolling elements  32  disposed between the rolling tracks of the inner  30 , and outer  31  raceways. The rolling bearing  25  may be kept circumferentially spaced by a cage  33 . Sealing members  34 ,  35 , situated on either side of the rolling elements  32 , include a metal stiffening insert and a flexible part. The sealing members  34 ,  35  include a securing flange accommodated in a corresponding groove in a raceway and a lip that may contact a surface of the other raceway. By virtue of the sealing members  34 ,  35 , the leak-tightness of the space contained radially between the inner  30  and outer  31  raceways and in which the rolling elements  32  are situated may be guaranteed.  
         [0036]     The pulley  24  may include two half-pulleys  36 ,  37 . Each pulley may include an outer cylindrical wall  36   a,    37   a  intended to make contact with a belt (not represented in the figure) and an inner cylindrical wall  36   b,    37   b  in contact with the outer surface of an outer raceway  28  of the rolling bearing  25 . The outer  36   a,    37   a  and inner  36   b,    37   b  cylindrical walls are connected by portions of radial cores  36   c,    37   c.  The half-pulleys  36 ,  37  are joined together, by mutual attachment of the radial cores  36   c,    37   c.  The half-pulleys  36 , 37  may be joined by a pin or by weld points.  
         [0037]     Each half-pulley  36 ,  37  includes a flank  36   d,    37   d  extending radially inward from the free edge of the inner cylindrical portion  36   b,    36   c  The flanks  36   d,    37   d  mask sealing members  34 ,  35 . The flanks  36   d,    37   d  serve to hold the pulley  24  axially on the outer raceway  31  and to protect the sealing members  34 ,  35  from the splash of external elements. The half-pulleys  36 ,  37  may also include radial centering rims  36   e,    37   e  that extend outward from the free edge of the outer cylindrical walls  36   a,    37   a.  The radial centering rims  36   e,    37   e  may guide a belt  38  in contact with the pulley  24 .  
         [0038]     A helical tension spring  14  is disposed between the base plate  8  and the radial wall  26 . A helical tension spring surrounds the tubular bushing  3  and an end of the working cam  2  covering the tubular bushing  3 . The helical tension spring  14  may be limited axially by the base  8  and the radial wall  26  and radially by the tubular bushing  3  and the axial wall  13 . One end  15  of the helical tension spring  14  may be curved outward so as to couple with circumferential retaining means of the base  8 . The other end of the spring  14  may similarly couple with the radial wall  26 . The helical spring  14  exerts a torque between the bracket  4  and the working cam  2  rotation-mounted on the bracket.  
         [0039]     In the assembly of the belt-tensioning device; a first stage includes adjusting the tension of the belt  38 . In order to do this, the screw  6  is loosened such that the adjusting cam  1  is rotationally movable relative to the block  5  and the bracket  4 . The adjusting cam  1  may be pivoted, by means of a control key, in the bracket  4 , which is rotationally immobilized relative to the block  5  by pin  10 . The pulley  24  is thus brought into contact with the belt  38 . The adjusting cam  1  is further rotated, which, by reaction of the belt  38  on the pulley  24 , induces the rotation of the working cam  2  relative to the bracket  4  with an increase in tension of the helical spring  14 . Increasing the tension of the helical spring exerts a resistant torque between the bracket  4  and the working cam  2  and the torque may force the pulley  24  permanently back against the belt  38 .  
         [0040]     The device may be designed such that the pulley  24  exerts a force on the belt  38  and generates a suitable tension in said belt  38  when the projection  29  of the working cam  2  arrives opposite the notch  12  in the bracket  4 . In this position, the screw  6  may be tightened such that the adjusting cam  1  is immobilized relative to the bracket  4  and relative to the block  5 . The metal insert  7  may allow absorption of the axial tightening forces exerted by the screw  6 .  
         [0041]     The helical spring  14  exerts a torque corresponding to the angular displacement between the bracket  4  and the working cam  2 . By virtue of this tension torque, a tension force of the belt in contact with the pulley  24  may be exerted.  
         [0042]     The skirt  27  forms a narrow passage with the axial wall  13  in order to make the seat of the helical spring  14  leak-tight. Moreover, the formation of a narrow passage allows the space situated between the axial portion  13  and the skirt  27  to be protected from the intrusion of pollutant outer elements which might interfere with the measurements conducted by the sensor unit formed by the coder ring  38  and the sensor  16 .  
         [0043]     In some embodiments, the free end of the the axial portion  13  may include a plurality of sensors  16 , circumferentially offset. Transmission of signals possessing a non-zero phase shift when the coder rotates past opposite said sensors may be possible by circumferentially offsetting the sensors.  
         [0044]     In one embodiment, the bracket  4  may be made of synthetic material. The bracket  4  may be formed by molding or injecting a material. In an embodiment, a bracket may be made of dished plateand may be used without a metal insert  7 .  
         [0045]     In some embodiments, during operation, when the pulley  24  is rotationally driven by the belt, the sensor unit allows the recovery of signals corresponding to the rotation parameters of the working cam  2  relative to the bracket  4 . Measurements of angular displacement, angular displacement velocity, frequency and amplitude of oscillation of the working cam  2  may be recovered. These signals possess components characteristic of the mechanical elements connecting to the working cam  2  (e.g., the spring  14 , the rolling bearing  25 , and the belt), as well as characteristics of distant elements in contact with the belt. Components characteristic of the meshing of the indexed belt with a toothed drive pulley may be retrieved. By analyzing the signals furnished by the sensor  16 , a record of tension of the belt, a record of wear or failure of the belt, a record of temperature-linked dimensional variations of the belt, or a record of failure of the tensioning device or of a particular member may be determined.  
         [0046]     The spring  14 , by virtue of the torque which it exerts, maintain a permanent bearing force of the pulley  24  against the belt  38 . A relationship exist between the tension variations of the belt, the wear of the belt and the slow mean angular displacements or the fast instantaneous angular displacements between the working cam  2  and the fixed bracket  4 . A belt-tension record may be determined from the value of the mean angular displacement between the working cam  2  and the bracket  4 . Mean angular displacement, in the context of this application, refers to a mean angular displacement over a short period of time, by which slow movements of the working cam  2  relative to the bracket  4  can be detected. Vibratory phenomena may be eliminated. The rapid and weak angular displacements of oscillation of the working cam  2  relative to the bracket  4  may be examined. The vibratory characteristics of the belt may vary according to the wear of the belt.  
         [0047]     In an embodiment, where there is a risk of imminent failure of the belt, the vibratory characteristics of the belt may vary. If the critical vibratory characteristics of the belt are known, it may be possible to determine the corresponding critical characteristics of angular displacement of the working cam  2 . For the working cam  2 , thresholds of angular displacement, angular displacement velocity, frequency and amplitude of oscillation of angular displacement, which constitute alarm thresholds for wear of the belt or for failure of the tensioning device, may be determined.  
         [0048]     Moreover, the measurements furnished by the sensor  16  in the assembly of the tensioning device may be used to adjust the tension of the belt or check the tension of the belt during the maintenance operation for the tensioning device. The presence of visual adjustment reference marks, notch  12  and projection  29  may not be necessary.  
         [0049]     The plug  19  may include a processing unit  21 . The processing unit  21  may pre-process the signals emanating from the sensor  16 . The processing unit  21  may include a program stored in memory means. The program may be executable by a microprocessor. The program may include a receiving module for the measurements furnished by the sensor  16 .The program may include a processing module for the received signals. The processing module may determine, in terms of output, a record of wear of the belt, failure of the belt or failure of the tensioning device. These records may be used directly such that the device may be stopped if the alarm threshold is exceeded. In the case of an automotive vehicle, for example, the detection of an imminent failure of the timing belt of the engine by virtue of an instrumented tensioning device may trigger a visual alarm (signal lamp on the instrument panel) or sound alarm alerting the driver to a potential problem.  
         [0050]      FIG. 2  depicts a cross-sectional view of an embodiment of a tensioning device. The tensioning device includes a swivel arm  40  with a pulley  24  at one end and a pivot bearing  41  at the other end. The pivot bearing  41  may be surrounded radially by a tension spring  14 . The pivot or bearing hub  41  is rotation-mounted on a fixed inner part  42  of a collar  43  forming a plain bearing. The fixed inner part  42  may serve as an axis for the pivot or bearing hub  41 . The fixed inner part  42  is fixed on the block  5  by a screw  6  passing through a bore  44  in the fixed inner part  42 . The fixed inner part  42  rests on the block  5  by means of a plate  45 . The plate  45  includes a stop pin  46  engaging in a notch  47  in the block  5  and a retaining lug  48  securing the first end  14   a  of the helical spring  14 . The opposite end  14   b  of the helical spring  14  engages a hole  49  in the swivel arm  40 . The helical spring  14  is pretensioned to exert a return torque which brings the pulley  24  back into contact with the belt  38 .  
         [0051]     A sensor block  50 , in the form of a crown may be fixed on the free end of the fixed inner part  42  by a holding collar  51 . The holding collar may include a radial portion  51   a  wedged between a radial end wall of the fixed inner part  42  and a head  6   a  of the screw  6 . A tubular wall  51   b  extends axially on the side opposite to the fixed inner part  42 . A radial wall  51   c  extends outward from the free end of the tubular wall  51   b.  The sensor block  50  is disposed on the outer surface of the axial wall  51   b.  The sensor block  50  is held between a radial shoulder  52  of the fixed inner part  42  and the radial wall  51   c.  A sensor  16  disposed in the sensor block  50  lies flush with the outer surface of the sensor  50 . The pivot bearing  41  includes an end  53  radially surrounding the sensor block  50  and a coder ring  54  flush with its inner surface, facing the sensor  16 .  
         [0052]     The pulley  24  is rotation-mounted on the swivel arm by rolling bearing  25 . the inner raceway  31  of rolling bearing  25  is fit onto a tubular sleeve  55 , made of dished plate, connected to the end of the swivel arm  40  and deformed to form a radial flange  56  for axially holding the inner raceway  31  in axial bearing contact on the opposite side against the end of the swivel arm  40 .  
         [0053]     The tensioning device may be operated similar to the embodiment of a tensioning device illustrated by  FIG. 1 .  
         [0054]      FIG. 3  depicts a representation of signals produced by an embodiment of sensors disposed on a tensioning device. The sensors may be circumferentially offset to provide a signal phase-shifted by half a period.  
         [0055]     In  FIG. 3 , the angular velocity, An, is plotted on the x-axis and the tension, V, of the signal furnished by the sensors is plotted on the y-axis. In an embodiment, a first signal, A, is a square-pulse signal with a period, T, assuming the values zero or one. The signal, B, is a square-pulse signal similar to the signal A and offset by a quarter of a period T/4. From these two signals, a square-pulse signal C is derived. Signal C, at a given instant, has a value one if the signals A and B vary in value and zero if they are equal in value. A period of signal C equal to the period of the signal A or signal B divided by two, i.e. T/2, is obtained. A resultant signal of better resolution is thus obtained from signals furnished by each sensor.  
         [0056]     The value of the period T is representative of the instantaneous angular velocity of the moving element relative to the fixed bracket. The angular displacement and hence the angular position of the moving element relative to the fixed bracket may be deduced from the signal C through the use of a pulse counter. In certain embodiments, the direction of rotation of the moving element relative to the fixed bracket may be deduced through the sign of the phase shift measured between the signals A and B.  
         [0057]      FIG. 4  depicts a representation of a signal that may be derived from the measuring signals of the sensors  16 . In  FIG. 4 , the time, t, is plotted on the x-axis and the value of angular displacement, α, between a working cam or a swivel arm and a fixed bracket is plotted on the y-axis. A first signal  60  is represented by a continuous uneven curve. The signal  60  oscillates about a mean signal  61  of so-called “mean” position embodied by a smooth curve. Instantaneously, the signal  60  oscillate about the mean signal  61  with an amplitude, W. Similarly, the signal  60  possess instantaneously a certain frequency of oscillation about the mean signal  61 .  
         [0058]     An angle of rotation, a mean angle of rotation, a rotation velocity, a frequency and an amplitude of oscillation may be obtained from the signals  60  and  61 . By processing signal  60 , it is possible to retrieve the frequencies and amplitudes of the multiple signals making up the signal  61  emanating from the sensor  16 . By analyzing the progression of these parameters of movement between the moving element and the fixed bracket, it is possible to detect a possible failure, wear of the belt, or an impending tear.  
         [0059]      FIG. 5  illustrates a variant of an embodiment of a tensioning device according to  FIG. 2 . The pulley  24  is in contact with a belt  62 , only one portion of which has been represented. The coder ring  54  may be a multipolar magnetic ring represented by a circumferential alternation of north pole and south pole. The sensor  16 , represented by dotted lines, may be buried in the sensor block  50 , fixed on the inner part  42  by screw  6 . The screw head  6   a  is visible. The block  50  includes a three-pin plug  19 , diametrically opposed to the sensor  16 .  
         [0060]     A supporting arm  63 , joined to the pivot bearing  41 , extends in radial projection. A hydraulic or pneumatic pusher  64 , fixed on the block by fastening lugs  65 ,  66  and screws  67 ,  68 , includes a body  69  and a push rod  70 . The push rod  70  comes to bear on a corresponding contact surface  63   a  of the supporting arm  63 . The rod  70  exerts a tension force upon the surface  63   a,  along an axis not passing through the rotation axis of the swivel arm  40  relative to the fixed inner part  42 . The pusher  64  thus enable a force to be exerted which causes the rotation of the swivel arm  40  and may achieve suitable tension in the belt  62 .  
         [0061]     The contact surface  63   a  may have a matched profile that allows perpendicular contact with the end  70   a  of the rod  70 . Allowing perpendicular contact may ensure appropriate transmission of the axial force such that the contact surface  63   a  can slide over the radial end  70   a  of the rod  70 .  
         [0062]     In some embodiments, an instrumented belt-tensioning device may processes the signals emanating from sensors for the parameters of movement of a moving element relative to a fixed bracket. Records of wear or imminent tearing of a belt may be detected. The records may also allow the tension of the belt to be adjusted initially or in the course of maintenance operations. Analyzing and processing the measuring signals may detect a failure of the actual tensioning device and even a failure of distant mechanical belt-driving elements. The instrumented tensioning device may continuously monitor the belt and its tension. The instrumented tensioning device may be simply constructed with low production costs.  
         [0063]     In some embodiments, the system may include a microprocessor with a CPU and a memory. A memory may be coupled to the CPU. A memory may include executable program instructions, such as a computer program. A computer program include modules for implementing a process for monitoring the tension of a belt tensioned by means of a tensioning device. The tensioning device may include a fixed bracket, a moving element relative to the fixed bracket, and an actuator that may exert a permanent tension force between the moving element and the fixed bracket. The computer program may include a module for receiving signals corresponding to parameters of angular displacement of the moving element relative to the fixed bracket, and a module for processing received signals. The module for processing received signals may furnishing a belt-tension record or a failure record on the basis of a movement value, a movement velocity value, and a frequency and amplitude of oscillation value.

Technology Classification (CPC): 5