FR2542297A1 - MEASURING AND INDICATING DEVICES FOR CABLE DRAWING WINCHES - Google Patents

Abstract

WINCH EQUIPPED WITH A TRACTION CABLE FOR PULLING ELECTRIC CABLES OR SIMILAR, EQUIPPED WITH DEVICES FOR MEASURING THE TENSILE FORCE AND THE LENGTH OF THE DRIVE CABLE, CHARACTERIZED IN THAT THE TENSILE FORCE IS MEASURED ON A FIXED SHAFT 1 CARRYING A ROTATING PULLEY 2 FOR THE TRACTION CABLE, IN THAT THE BEND OF THE SHAFT 5 WHICH IS A FUNCTION OF THE TENSILE FORCE IS TRANSFORMED BY EXTENSOMETRIC GAUGES 3 INTO ELECTRICALLY MEASURABLE VALUES AND IN THAT THE EXTENSOMETRIC GAUGES ARE MOUNTED ON A FLAT SURFACE OF THE SHAFT 1.

Description

2542297 Y

  For controlled hauling of electric cables or

  assimilated telecommunications, transmission, if-

  or for transporting energy in sheaths for cables

  electric winch or in trenches, winches driven by motors, mounted on a towed chassis or on a self-propelled vehicle are used which are equipped with measuring and indicating devices intended to determine the pulling force exerted on the pulling cable of the winch and the

  length of this traction cable Characteristics are required

  high ticks from these measuring and indicating devices

  tion of these electric cable winches because we have to draw electric cables which can be

  on the one hand, more or less robust and, on the other hand,

  Very fragile or sensitive to stresses by tensile forces One can cite, for example, as fragile similar cables of the most recent technique,

  fiber optic cables which are part of the head cables

  lecommunications Apart from these purely technical specifications, one seeks to make the operation of a winch of

  cable pulling as convenient and safe as possible.

  As part of the operations to be carried out before the drawing of electric cables in sheaths, pulling winches are also used, for example to pull

  appropriate brushes through the sleeves to clean

  tyer these and / or calibration devices intended

  to determine the free internal diameter of the sheaths.

  The measurement of the traction forces of a winch

  traction cable is made possible, in constructions

  tions already known, by deflecting the rectilinear path of the traction cable between two pulleys with traction cable, using a third mobile pulley, possibly mounted with a spring The tension of the traction cable of the winch determines on the mobile pulley a force component which is directly proportional to the tensile force of the

  traction cable The movement of this pulley is trans-

  put on an indicating instrument, composed of a needle and a calibrated graduation, either directly, or by means of lever mechanism, or for example, by means of lever mechanisms and a hydraulic dynamometric capsule and, so it is

  made legible or, if the indicating instrument is

  killed by a continuous plot recorder fitted with a paper strip, it is recorded in the form of a variation curve of the traction force In the case of the continuous plot recorder, the advancement of the strip

  of paper is controlled either by a motor or a mechanic

  spring-loaded, that is to say that it is produced as a function of time, either by the fact that the paper feed drive is mechanically connected by means of a flexible shaft to an appropriate pulley of the guide of the winch traction cable inside this winch, which

  allows a recording of the traction force in function

tion of the length.

  Recording a cable pull operation

  electrical and assimilated wheat which has been recorded by a continuous line recorder consists of a strip of paper of varying length on which the curve of

  variation of the tensile force is recorded in function

  time or length, in which case the continuous-line recorder must still be accompanied by a reading rule which must itself bear the same calibration marks as the recorder to enable the different values to be read. the tensile force when you have it

detached the strip of paper.

  The indicating instrument or track recorder

  continuous is fitted with switching-operating devices

  hand by means of which the maximum limit value of the tensile force of the type of electric cable or the like which must be pulled can be adjusted If the force

  of instantaneous traction reaches the limit value, the

  positive switching cuts the winch drive to

  thus avoid overloading of the cable to be pulled.

  The object of the invention is to provide a traction cable winch for the pulling of electric cables and the like, of the type indicated above in which the values of the traction force and the cable length

  are transformed directly as posi

  sible in electrically measurable values.

  To this end, the subject of the invention is such a winch which includes devices for measuring the pulling force and the length of the pulling cable which

  is characterized in that the tensile force is me-

  made on a fixed shaft carrying a rotating pulley with traction cable, in that the flexion of the shaft which is a function of the traction force is transformed by strain gauges into electrically measurable values and in that the gauges are mounted on

a flat surface of the tree.

  Other features and advantages of the

  vention will appear during the description which goes

  follow In the accompanying drawings, given only as

example,

  Fig 1 is a sectional view of the device, on which there is shown: the shaft 1, the traction cable pulley 2, the strain gauge 3, the cell 4, the sheet metal tabs 5, the hollow cylinder 6 and a seal 7;

  Fig 2 is an elevational view of this arrangement

  tif which shows the shaft 1, the traction cable pulley 2, the traction cable 8 and the force component 9 Fig 3 shows in section a traction force sensor associated with an inductive length sensor, for a winch draw; the Fig showing the pulley 2, the traction cable 8, the force component 9, the inductive length sensor 10, the coil 11 of the sensor, the core 12 in metal and the spring 13; FIG. 4 is a sectional view of a tip for starting a traction cable for a winch according to the invention, a figure in which, in addition to the elements already mentioned, an insulating conductor is shown at 15 and the tip itself - even in 14; FIG. 5 shows a section through a start end of a traction cable for a winch according to the invention provided with a calibration apparatus, the figure showing in

  in addition to a guide element 16 and a cable sheath 17.

  For entering measured force values

  tensile strength and cable length, the invention

  therefore takes the path of transformation as direct as

  possible in electrically measurable values

  serve the principle of producing a force component 9 by deflecting a straight cable path

  by means of a third cable pulley The third pul-

  cable link, which turns freely, is however mounted on

  a fixed shaft 1, the variable force component determined

  nant a slight variable bending of the tree, which is trans-

  formed in an electrically measurable quantity using at least one strain gauge 3 which is mounted on a flat surface of the shaft The gauge (s) can be protected by a fixed hollow cylinder 6 in the shape of a bell

  and by a seal 7, for example a gar-

  lip sealant that can lean against the

pulley 2.

  A variant of the direct transformation of the

  pulling force is to use a length sensor

  inductive sensor 10 comprising a coil 11 with central grip

  and a nucleus 12 of movable or displaceable metal

  positional mutations of the metal core 12 generate measurable variations in the electrical characteristics of

  the coil 11 insofar as it is supplied with

  rant alternatif According to the invention, the displacement of the nucleus

  12 in metal is caused by a third cable pulley

  spring-loaded traction hose 13 over which the traction cable 8 passes and to which the latter transmits a

  force component 9 proportional to the pulling force

  tion. From the traction force measurement device located on the winch itself, the sum of the traction forces acting on the traction cable is recorded.

  during the electric cable or cable pulling operation

  milé, sum which breaks down as follows A Weight (mass) of the traction cable B Friction of the traction cable in the sheath of the electric or similar cable or in the trench C Weight (mass) of the electric or similar cable fixed to the traction cable D Friction of the electric cable or the like in the sheath or trench,

  E Force required to unwind the electric cable

  than or assimilated to a feed drum.

  In recent constructions of cable winches

  traction, devices for measuring the force of

  traction or additional measuring devices se-

  condaires are arranged at the free end of the traction cable so that these devices only record

  the tensile forces C, D and E mentioned above.

  These forces are those which act on the electric cable or similar to be pulled, for which the manufacturer gives in each case a maximum specific tensile force not to be

  not exceed Traction force measuring devices

  tion placed at the start of the pulling cable do not take into account the pulling forces A and B This arrangement is particularly important when the winches are used for pulling cables that are particularly sensitive to traction, for example glass fiber cables and that

  the tensile forces A and B make up a relative part

  tively important of the sum of the traction forces, because then for example, the weight and the frictions of the traction cable (A and B) are greater than those of the cable

  electric or similar (C, D and E).

  The invention relates to the production of the end-piece 14 of the traction cable situated at the free end of the latter as well as the devices provided at this location for the measurement of the traction forces. This end-piece 'comprises two parts which are mechanically- coupled to each other at

  one of the parts is quickly fixed

  ment to the traction cable 8 of the winch, the coil 11 of an inductive sensor of length 10 being incorporated therein. The connection wires of the coil are connected, inside this part, to insulating conductors 15 which must be provided at inside the traction cable 8 and used to transmit the values electrically measurable by the inductive sensor of length 10 to the electronics provided

in the winch.

  The second part of the end piece 14 includes the

  mechanical elements for fixing, for example, a

  chon or a cable or electric cable pulling head

  milé, and is fixed to the metal core 12 of the inductive sensor

  of length 10 If we assemble the two elastic parts-

  appropriately, the core 12 moves in the

  coil 11 proportional to the pulling force applied

  quée at the end piece 14 when drawing the electric cable or

assimilated.

  The second part can also be performed

  as a calibration device to measure the diameter in-

  sheath 7 of cables In this case also, the measurement value is transformed directly into an electric measurable value This second part then comprises several mechanical probes 16 which are resiliently

  in contact with the inner wall of the sheath 17 Lors-

  that this calibration device is pulled through the sheath 17, the elastically mounted feelers 16 are displaced as a function of the internal diameter of the sheath This movement is mechanically transmitted to the core 12 in mumetal for

  cause variations depending on the diameter of the characters

  electrical characteristics of the coil 11 of the sensor 10 and thus provide electrically measurable values which, as described below, are processed in the system to

winch microprocessor.

  To measure the displacement of the traction cable and its length, use is made at an appropriate point of the winch, for example on the fixed shaft 1 or on another pulley for guiding the traction cable for example as in the case of strain gauges , a magnetic or optical cell 4 which is influenced, by magnetic means or by occultation, for example by sheet metal tabs 5 or by a diaphragm with holes which is set in motion by a cable pulley 2 and which emits under this effect electrically measurable pulses The dimension chosen for the

  traction cable pulley as well as the number of lans

  sheet metal watchdogs which influence the cell at each revolution of the traction cable pulley gives a certain number of electrical pulses per revolution and, consequently, per unit of length, for example one pulse for the Ocm of

length of the traction cable.

  Analog values, electrically measurable

  strain gauges or inductive length sensor

  as well as the impulses of the cell can be transformed into numerical values, evaluated, calculated and,

  counted in a microprocessor system and made identical

  for service personnel on components

  electric indicators The indication of the pulling force

  tion in figures on a display is not advantageous because these quantities vary very frequently during the printing operation, and this so quickly that they cannot be detected and read by the service personnel. However, the observation of the tensile force during the very drawing of a telecommunication or energy transport cable constitutes one of the pieces of information

  most essential for service personnel.

  According to the inyenti Qntf the force of ti "çti Qn is af-

  plugged into a light strip to be very simple -

  noticeably peace of mind for the operator.

  The light strip is made up of a big name-

  bre, ten for example, of lamps or light-emitting diodes

  nescents which are arranged one beside the other or one above the other to form a band Before the start of the pulling operation, a maximum value of the force is stored in the microprocessor system

  which is specific to the type of cable to be pulled.

  This maximum value of the pulling force is used to set

  the winch stopped under the microprocessor control when

  that the maximum value is reached or exceeded during the

  draft, however, as long as this maximum tractive force has not been exceeded, the system

  microprocessor calculates the fraction of the traction force

  instantaneous measurement as a percentage of the pulling force

  maximum stored memory and it controls its electrical outputs

  triques in such a way that the result is represented on

  the light strip in the form of lamps or electro-diodes

  luminescent which are switched on or off If the instantaneous pulling force exerted during the pulling operation reaches, for example 60% of the maximum pulling force,

  six of the ten (or twelve of the twenty) lamps or diodes

  the luminous stripes light up.

  Another advantageous working information for the winch service personnel is the indication of the speed of the moving traction cable, for example in meters per minute. For the calculation of this indication, the magnetic or optical cell produced, for example, an impulse

  sion by length of 10 cm of the moving cable, i.e.

  say per unit length of speed measurement The sys-

  microprocessor is able to produce a clock signal or a time measurement, that is to say the unit of time and to calculate from the two data the deflection speed of the cahlaef which Ie aet gneuite indicated on a display with gepia with continuous play, The microprocessor-based system allows you to plug in a printer on paper tape, as well as to introduce specific texts and to save intermediate and maximum values of the pulling force, the length and speed; From all this data,

  we can produce and print a pre-work report

  felt in the form of an archivable form which, apart from the graphical representation of the variation curve

  tensile force and length, all para-

  meters and incidents of a dilun cable pulling operation

electric or similar.

  It has already been indicated that the microprocessor system

  of the winch can provide instantaneous speed data

  of the pulling cable and the pulling force These data

  are displayed The operator responsible for operating the winch must manually adjust the speed of the winch and thus the pulling operation so that it obtains the highest possible speed of the traction cable without

  exceed the limits of the tensile force.

  The speed of the traction cable is adjusted by means of a lever which regulates the flow of hydraulic fluid in the hydraulic winch drive device. In the case of an electric drive, this lever has a corresponding electrical function of setting the

speed of the traction cable.

  The invention includes an electronic control of the adjustment lever, for example with an adjustment motor which is slaved to the microprocessor system. For example if the traction force is at 25% of the limit, the speed

  winch can automatically be increased by this setting.

  On the other hand, if the tractive force reaches 95% of its limit, the microprocessor system can be programmed in such a way

that it reduces this speed.

Claims (7)

CLAIMS 1, Winch provided with a pulling cable for the pulling of electric cables or similar, equipped with devices for measuring 1 l pulling force and the length of the S Don tractor cable, characterized in that the force of traction is measured on a fixed shaft (1) carrying a rotating pulley (2) for the traction cable, in that the bending of the shaft (5) which is a function of the traction force is transformed by strain gauges (3) in electrically measurable values and in that the strain gauges are mounted on a flat surface of the shaft (1).   2 Winch according to claim 1, characterized in that the length of the traction cable is sensed by a magnetic or optical sensor (4) comprising sheet metal tabs or diaphragms with holes (5) which exert a magnetic action or obscure a path optical and which are mounted on the rotating pulley (2) for traction cable and in this   that the fixed sensor (4) emits pulses or signals typically   As for its components, the sensor can also be mounted on the rotating pulley (2) while the sheet metal tabs or the diaphragm with holes (5) can be mounted fixed.   3 Winch according to any one of the claims   1 and 2, characterized in that the strain gauges   that (3) and the magnetic or optical sensor (4) are mounted on a fixed shaft (1) and in that these elements are protected from external influences by a hollow cylinder   (6) fixed in the shape of a bell as well as by a gasket   seal (7), for example, a gasket   lips, the gasket resting against the   rotating link (2) for traction cable.   4 Winch fitted with a traction cable for the   rage of electric cables or similar with devices   traction force measuring devices, characterized in that it is intended for the transformation of the traction force 254229?   in electrically measurable values, a length sensor   inductive sensor (10) whose core (122 in nurmetal is displaceable by means of a pulley l 2) for traction cable   spring mounted (13), by means of which the cable.   traction (8) transmits a force proportional to the force traction.   Winch according to claim 4, characterized in that the inductive length sensor (10) 'is mounted   in a ferrule (14) of the traction cable, this sensor comprises   both two parts which are connected to each other by a spring (13) and whose elastic effect is exploited to ensure movement as a function of the traction of the core (12) in metal of the sensor (10).   6 Winch according to any of the claims   cations 4 and 5 characterized in that the traction cable (8)   is used for the transmission of electrical measured values   triques of the sensor (10), this cable comprising for this purpose an insulating conductor (15) of suitable proportions; 7 Winch according to claim 5 characterized in that the first part of the end piece (14) made of two elastically connected parts comprises mechanical feelers (16) elastically biased (13) and capable   to explore the inner wall of a sheath (17) to determine   mining the internal diameter, the variations of this diameter being transformed into a movement of the core (12) into the mumretal of the inductive length sensor (10) and thus into values electrically measurable.   8 Winch according to any of the claims   cation 1, 2, 4 and 5 equipped with a microprocessor device which processes the electrically measurable values of said   strain gauges and / or said magnetic sensor or op-   tick and / or said inductive length sensor, and to which corresponding output components are connected such as,   for example a printer, displays and LED indicators   mining, characterized in that the pulling force is displayed   on a light strip made up of several lamps or dio-   S Qus electroluminescent lamps   successive age in such a way that the number of elements   of the luminous hande which are lit or spotted is always   days proportional to the percentage of a pulling force   preset maximum that represents the pulling force ins-   tantane. 9 Winch according to claim 8 when it   depends on claim 2, characterized in that the pulses   electrical sions, relative to the length, of the magnetic sensor   tick or optical (4) and a clock signal produced by the microprocessor device are used together to calculate the running speed of the traction cable and   to indicate: this speed on a display.   10 Winch according to claim 8, characterized in that the printer prints on paper a graphic representation of the tensile forces and the length of the winch's traction cable as well as a text of the form type, and the limit data of the force tension, length and speed of the winch cable, to establish a   report of the entire cable pulling operation.   11 Winch according to claim 9, characterized   in that the speed of the traction cable calculated by the system   microprocessor teme as well as the measured tensile force   instantaneous are used for the electronic control of a maximum speed of this cable below the limit adjustable traction force.