FR2474231A1 - Ribbon winding machine for electrical cables etc. - has constant couple drive and self tensioning lever roller system for guiding ribbon - Google Patents

Abstract

The machine typically wrapping an electrical conductor into a helix of insulation. The wrapping action is continuous as the conductor is automatically fed through and automatically adjusts its own tension. The wrapping head is mounted at the top of a column the line to be wrapped passing through a horizontal tubular channel at its centre. The ribbon used as wrapping is stored on a drum coaxial to the channel and set at the output end of it. Tension on the ribbon is maintained by passing it through a hairpin path over two rollers over an arm parallel to the line path and over two further rollers the last roller guiding the ribbon over the line. Coupling to the rotating shell of the winder can be via a constant couple friction clutch capable of giving the drum at least the acceleration of the shell.

Description

 the invention relates to a machine for wrapping a linear product of a ribbon or a wire helically deposited on said product. This may for example be to provide a bare electrical conductor with an insulation tape, or to bind a target beam of conductors or elemental targets by means of a string wire.

The invention relates more precisely to a machine of the type comprising
a fixed rectilinear tube through which the product to be wrapped (driver or target) travels,
a sleeve rotating coaxially around said tube and carrying a winding product drum (ribbon or wire),
a bowl rotating coaxially around said tube and said bobbin, rotated by a control shaft and carrying rollers for guiding the wrapping product which unwinds from the bobbin and moves towards the product to be wrapped,
a tension compensator comprising a rod movable in rotation around the bobbin with respect to the bowl and biased in one direction by the tension of the wrapping product, which passes on this rod at its exit from the bobbin, and in the opposite direction by a return spring towards an abutment integral with the bowl, and
- A device for controlling the speed of rotation of the bobbin relative to that of the bowl.

 In known machines of this kind, the latter device consists essentially of a braking band of the bobbin attached on the one hand to the movable rod of the compensator and on the other hand at a point of the bowl. With the control of the compensator, this band stretches or relaxes and slows down more or less the rotation of the bobbin, which turns crazy with its carrier bushing being simply 'entras by the wrapping product, so as to stabilize the tension of said product from of the bobinot.

 Such a mode of regulation involves the use of relatively light bobbins (patties), because its effectiveness would be insufficient in the case of heavy bobbins, and the wrapping product, still quite fragile (paper ribbon for example), would not fail It is difficult to break during the transient regimes (acceleration, deceleration) where the speed of the winding must vary rather rapidly, and the essentially variable mass of a winding-pipe poses difficult problems. that it takes the ehan3e often during the march of each machine.

 In order to allow the use of large-capacity and therefore heavy-duty bobbins, the object of the invention is a machine of the kind indicated, the device for controlling the speed of the bobbin comprising positive drive means in rotation of the carrier bushing. of the bobbin at a variable speed relative to that of the bowl, this speed being adjusted, from a sensor measuring the angular position of the compensator in the bowl, so that the tension of the wrapping product leaving the bobbin remains constant The regulation of the speed of the bobbin by positive drive of the latter, which is therefore no longer simply driven by the product that it delivers, makes it possible to solicit it more vigorously and ensures perfect operation with heavy bobbins of great capacity.

In a first embodiment, said positive drive means comprises a friction coupler interposed between the bowl and the bushing, the latter being rotated from the control shaft via a coupler The magnetometer is excited from the sensor to change the rotational speed of the bobbin relative to that of the correlatively sliding bowl of the friction coupler, thereby maintaining the tension of the wrapping material constant. As a result, the invention makes it possible to reduce the number of machine stops necessary to change the winders so that the efficiency of the machine is increased and the number of operators serving a battery of machines can be increased. greatly decreased. / se the invention
according to the invention
In a second embodiment of the machine /, the positive drive means of the bobbin comprise a variable speed drive which is controlled from the sensor and through which the bushing is driven from the control shaft. at a speed more or less different from that of the bowl according to the information provided by the sensor, so as to change the speed of rotation of the bobbin relative to that of the bowl and thereby maintain the tension of the wrapping product.

 The aforementioned variable speed drive can be a mechanical drive whose transmission ratio is set from the sensor. According to an advantageous variant, the variable speed drive is an electronic variator constituted by a variable speed motor, a reference dynamo and an electronic control unit that adjusts the speed of the motor according to the information of the sensor and the dynamo.

 In general, the maximum value of the relative rotational speed of the bobbin and the bowl may be chosen equal to about 10X of the rotation speed of the bowl.

 The following description, with reference to the accompanying drawings by way of non-limiting examples, will make it possible to understand how the present invention can be put into practice.

 Figures 1 to 3 show a partial section respectively three embodiments of a machine according to the invention.

FIG. 4 represents a view according to the arrow
IV of part of the object of Figures 1, 2 or 3.

 FIGS. 1 and 4 show that a machine according to the invention smpends a vertical bit 5 mounted on a base 6 and carrying a horizontal tube 7 running from left to right on a target 8 to be processed, here here a simple conductive wire to receive an insulation tape 9 wound in helical coils. This ribbon is cut by a bobbin 10 fixed on a sleeve 11 which can rotate coaxially around the tube 7 with two ball bearings. A ribbon tension compensator, which can oscillate freely around the sleeve 11 by means of another pair of ball bearings, comprises a radial rod 12 terminating in a finger 13 which is parallel to the wire 8 and on which the ribbon 9 passes through. 10. The ribbon 9 also passes, in order to guide it to the wire 8, on the return rollers 14, 15 and on the fretted rollers 16 and the jetty 17, all integral with a rotary bowl. 18 coaxial with the tube 7 and rotating around the sleeve 11, graced by two ball bearings, under the action of a control shaft 19 to which it is connected by a transmission 38 comprising a pulley 20 wedged on the bowl 18 a belt 21 and a pulley 22 ealée-on the shaft 19.The rod 12 of the compensator is biased by a spring 23, hooked at a point of the bowl 18 against a stop 24 integral with the latter. the compensator is coupled by gears 25,26 to a potentiometer 27 mounted in the bowl 18> 18, which-constitutes an angular position sensor of the compensator and whose terminals are accessible on the outside of the bowl on three trotters 28 sliding on a triple conducting track 29.

 In the embodiment of Figure 1, the bowl 18 is rotatably coupled to the sleeve 11 by a friction coupler 30 calibrated at a constant torque and capable of imposing on the bobbin an acceleration at least equal to that of the bowl.

On the other hand, the bushing 11 is rotated by the control shaft 19 by the intermediary of a trans
stalled mission 39 comprising a pulley 31 on the sleeve 11> a belt 32, a pulley 33 wedged on the output member of an electromagnetic coupler 34, a pulley 35 wedged on the input member of the latter, a belt 36 and a pulley 37 wedged on the shaft 19,
When the wire 8 runs and the bowl 18 rotates, entrained by the transmission 38, the bobbin 10, carried by the sleeve 11, rotates at the same speed as the bowl 18 because of the friction die-coupler 30, assuming the electronic coupler The relative speed of the bobbin and the bowl is then zero and the bobbin does not deliver ribbon 9. The tension of the ribbon increases, which causes the compensator to pivot in the bowl, the rod 12 of which leaves the abutment. 24. The movement is detected by the potentiometer 27 which controls, via a link 40, the supply of the excitation coil 41 of the electromagnetic coupler 34. Since, by construction, the output pulley 37 of the latter (Driven by the belt 32) rotates faster than its input pulley 35 (entrained by the belt 96), the excitation of the coupler 34 causes a braking of the bushing 11 (with correlative sliding of the coupler) 0) and consequently of the bobinot 10 which then delivers 9, while the compensator stabilizes, in the absence of disturbance, in a position of equilibrium with respect to the bowl for which the tension of the ribbon is constant, its value depending on the adjustable force of the return spring 23.

Is
1 the speed of rotation of the bowl 18,
, 2 the speed of rotation of the bobbin 10,
CM the mechanical friction torque
coupler 30 (this torque is constant),
CR the dG torque at the voltage of the
ribbon 9 (in parallel with the CM couple)
CE the torque transmitted by the electro coupler
magnetic 34,
d the diameter of the wire 8,
D the winding diameter of the
bobinot 10 (variable), and
p the step of the ribbon 9 on the wire 8.

The relative speed of = # 2 - # 1 of the bobinot 10 with respect to the bowl 18 has for

<tb> expression <SEP>: <SEP> 2
<tb><SEP> LU <SEP> P2 <SEP> + <SEP> (n <SEP> di2
<tb><SEP> 4w = <SEP> I
<tb><SEP>,<SEP> D
<tb> the sign - meaning that the direction of the relative speed ## is opposite to the direction of the absolute speed su 2
If, for example, d = 1.2 mm, # 1 = 3000 rpm, p = 27 mm, 90 f d ç 200 mm, we find
## = - 130 rpm for D = 200 mm
## = - 290 rpm for D = 90 mm
At equilibrium, we have
CM = CE + CR, or CE = CM - CR.

Under transient conditions (acceleration, deceleration), the balance is disturbed by the inertia of the bobbin. The torque necessary for the acceleration or deceleration of the bobbin 10 and its bushing 11 can be written (J being the moment of inertia of all of these two elements) C = Jdw
dt
From where the value of the friction torque CM necessary in acceleration (with CE = 0): CM = CR maxi + JC, and the value of the magnetic torque CE necessary in deceleration
CE = CM - CR mini + JC; if we assume that CR mini has negligible value, it remains: CE = CM + JC

 In this embodiment, it is the friction coupler - - - - - 30 which ensures the acceleration of the bobbin and the electromagnetic coupler 34 which ensures its deceleration. The formulas above allow to choose the constant value to be given to the CM pair and the maximum value that the CE pair must be able to reach.

By way of example, a speed of 1000 rpm can be chosen for the control shaft 19. The ratio of the diameters of the pulleys 22 and 20 as well as the pulleys 37 and 35 being 3: 1, the bowl 18 and the input element of the coupler 34 rotates at 3000 rpm, while the ratio of the diameters of the pulleys 31 and 33 is 1.1: 1, the output element of the coupler 34 rotates at 3300 t / -n (in the absence of excitation of ee last, thus of sliding of the coupler 30.) When the coupler 34 is sufficiently excited, it is capable of braking the speed of the sleeve 11 and the bobinot 10 to an equal value at D000 = 2730 rpm
1.1 corresponding to - = - 270 t / min, value close to the value calculated above for a bobbin having reached a minimum diameter of 90 mm. The relative speed uv therefore has a maximum value equal to about ten of the speed of the bowl 18.

 In the example shown (Figure 4), it is a slowing of the winding 10 which causes an increase in the flow of ribbon 9. If the windings of the winder were wound in the opposite direction, it is obviously an acceleration of the winding which would cause a increase of the aforesaid flow; it would then suffice to intervertr pulleys 31 and 33. A similar remark can store made for other forms of execution that now go between described.

 In the embodiment of Figure 2, the friction coupler 30 is removed and the transmission 39 is changed. It is now constituted by a pulley 41 wedged on the control shaft 19, a belt 42 and a pulley 43 wedged on the input shaft of a mechanical speed variator 44 with geared motor, then by a pulley 45 stalled on the output shaft thereof, a belt 46 and a pulley 47 wedged on the sleeve 11 carrying the bobbin 10. The variations in the ratio between the rotational speeds of the input and output shafts of the variator 44 are controlled from the information provided by the potentiometer 27 as a function of the tension of the ribbon 9.

 When the ratio of the variator is 1: 1, the transmissions 38 and 39 are such that the bobbin 10 and the bowl 18 rotate at the same speed, so that the relative speed A w of the winder is zero and that it does not debit 9. Under the control of the potentiometer 27 actuated by the compensator 12, 13, the ratio of the variator 44 decreases, so that the sleeve 11 slows down and the bobbin 10 turns slower than the bowl 18. Ribbon 9 and then debited and a state of equilibrium is reached.

 By way of example, the transmission 38 may be identical to that of FIG. 1, the ratio of the diameters of the pulleys 41 and 43 may be equal to 1: 1, that of the pulleys 45 and 47 may be equal to 3: 1 and the ratio the variator 44 is between 0.9 and 1. Then, as in the case of Figure 1, the bowl 18 all at a speed of 3000 rpm and the bobbin 10 at a speed between 3000 and 2700 rpm , so that the relative speed ss can reach 10% of the value of the speed w 1 of the bowl 18.

 The embodiment of FIG. 3 is deduced from that of FIG. 2 by a new modification of the transmission 39. This latter now comprises, from the pulley 41 wedged on the shaft 19, a belt 48 and a pulley 49 set on the shaft of a reference dynamo 50 and a pulley 51 set on the shaft of an electric motor 52 DC, a belt 53 and finally the pulley 47 wedged on the sleeve 11, while the The speed of the motor 52 is regulated by an electronic control unit 54 comparing the information it receives from the potentiometer 27 and the reference dynamo 50.

 In the example shown, the ratio of the diameters of the pulleys 41 and 49 is 3: 1 and that of the pulleys 51 and 47 of-1: 1. The electronic block 54 varies the ratio of the speeds of the dynamo 50 and the engine 52 between 0.9 and 1. The operation is then in all points sembt the one of the machine of Figure 3.

 In practice, a machine according to the invention can make it possible to use coils of large capacity weighing 6 or 7 kg and that in a store-like manner, without breaking the product delivered by the coils mame when it comes to a fragile strip of paper 5 mm wide and 0.06 mm thick; because the tension of said product is no longer dependent on the mass of the bobbin and dense variations. Such a machine can then operate without interruption for 6 to 7 hours at its maximum speed for wrapping or strapping a conductor or a traveling target at high speed (for example 3000 steps / min).

 The number of operators required is therefore reduced compared to that required by the known machines, which must be stopped approximately 3 times per hour in order to change the bobbin and which consequently require one operator per group of six. or 7 machines, while the same operator can serve a number about 20 times larger-machines according to the invention, or at least a hundred machines.

Claims (6)

 1.- Wrapping machine for electric conductors or strapping targets, comprising  - A fixed rectilinear tube through which scrolls the product to be wrapped (driver or target).  characterized by the fact that the latter device comprises positive rotation drive means of the carrying sleeve of the bobbin at a variable speed relative to that of the bowl, this speed being adjusted, from a sensor measuring the angular position of the compensator in the bowl, so that the tension of the wrapping product leaving the bobbin remains constant.  - a device against the speed of rotation of the bobbin relative to that of bel,  a tension compensator comprising a rod movable in rotation around the bobbin with respect to the bowl and biased in one direction by the tension of the wrapping product, which passes on this rod at its exit from the bobbin, and in the opposite direction by a return spring towards an abutment integral with the bowl, and  a bowl rotating coaxially around said tube and said bobbin, driven in rotation by a control shaft and carrying rollers for guiding the wrapping product which unwinds from the bobbin and moves towards the product to be wrapped,  a sleeve rotating coaxially around said tube and carrying a wrapping product winding (ribbon or wire),  2. Machine according to claim 1, characterized in that said positive drive means comprise a friction coupler interposed between the bowl and the sleeve, the latter being rotated from the control shaft by the intermediate of an electromagnetic coupler which is excited from the sensor so as to modify the speed of rotation of the winding with respect to that of the bowl with correlative sliding of the friction coupler, and thus to maintain the tension of the product of wrap.  3. - Machine according to claim 1, characterized in that said positive drive means comprises a variable speed drive which is controlled from the sensor and through which the bushing is driven from the control shaft at a speed more or less different from that of the bowl according to the information provided by the sensor, so as to change the speed of rotation of the bobbin relative to that of the bowl and thereby maintain the tension of the wrapping product.  4. Machine according to claim 3, characterized in that the variable speed drive is a mechanical drive whose transmission ratio is set from the sensor.  5. Machine according to claim 3, characterized in that the variable speed drive is an electronic variator consisting of a variable speed motor, a reference dynamo and an electronic control block regulating the speed of the engine according to the information sensor and dynamo.  6.- Machine according to any one of claims 1 to 5> characterized in that the relative speed of rotation of the bobbin and the bowl is at most equal to about 10% of the rotation speed of the bowl.