Controlled cable transport installation

Cable transport installation having an operating phase and a test phase comprising:

• a first pulley and a second pulley, around which travels a closed loop formed of a carrier-tractive cable or a tractive cable, at least one of the two pulleys being driven by a motor controlled by control means;
• a shaft of the first pulley attached to a first fixed frame of the installation;
• means for measuring the torque on the drive pulley;
• computing means for comparing the torque with an adherence threshold and producing a control or alarm signal if the threshold is reached or exceeded;
• a shaft of the second pulley retained by a second fixed frame of the installation;
• retaining means maintaining the shaft of the second pulley in a substantially constant position on the second fixed frame of the installation during the operating phase of the installation;
• means for measuring the tension of the cable and producing a signal which is the image of said cable tension, the signal being applied to an input of a computing and control assembly;
• a computing and control assembly receiving the signal produced by means measuring the tension of the cable, comparing said signal repeatedly with a predetermined minimum threshold and a predetermined maximum threshold and producing at its output an alarm signal when the tension measurement is less than the predetermined minimum threshold or exceeds the predetermined maximum threshold.

Cable transport installation having a test phase and an operating test phase comprising:

• a first pulley and a second pulley, around which travels a closed loop formed of a carrier-tractive cable or a tractive cable, at least one of the two pulleys being driven by a motor controlled by control means;
• a shaft of the first pulley attached to a first fixed frame of the installation;
• a shaft of the second pulley, mounted for rotation on an independent carriage of a second fixed frame, guided by vertical guide means allowing longitudinal movement and lateral pivoting thereof parallel to the plane defined by the two cable sides leaving the pulley;
• two retainer stop means, which are provided on the second fixed frame and are offset laterally with respect to the mean direction of the cable, for:
• a. retaining the independent carriage;
• and
• b. maintaining the shaft of the second pulley in a substantially constant position on the second fixed frame of the installation during the operating phase of the installation;
• a first force sensor, associated with the first retaining stop means, and a second force sensor, associated with the second retaining stop means, which force sensors are located between the second pulley and the fixed frame for measuring the force retaining the carriage exerted by the retention stop means, the force sensors producing a signal which is the image of the cable tension, the signal being applied to a computing and control assembly;
• means for measuring the tension of the cable and producing a signal which is the image of said cable tension, the signal being applied to an input of a computing and control assembly;
• the computing and control assembly receiving the signals produced by each of the two force sensors and receiving the signal produced by means measuring the tension of the cable, which computing and control assembly:
• a. computes the cable tension, the relative tension of the two cable sides and the torque produced by the pulley;
• b. compares said signal produced by means measuring the tension of the cable repeatedly with a predetermined minimum threshold and a predetermined maximum threshold and delivers an operation enabling signal or operation disabling signal after the comparison;
• c. produces at its output an alarm signal when the tension measurement is less than the predetermined minimum threshold or exceeds the predetermined maximum threshold;
• and
• d. is a programmable automation program for carrying out a previous test phase under predetermined load conditions, during which it compares the tension of the cable with two maximum and minimum limit values, the limit values being chosen so that the installation will operate normally, under appropriate safety conditions, without loss of adherence and without reaching the maximum cable tension threshold during the operating phase which follows the test phase, under the usual operating assumptions.