WO1997027136A1

WO1997027136A1 - Cushioning pad production machine with a system for measuring the length of the resulting pad

Info

Publication number: WO1997027136A1
Application number: PCT/FR1997/000123
Authority: WO
Inventors: Théodore Baumuller
Original assignee: Naturembal (Societe Anonyme)
Priority date: 1996-01-22
Filing date: 1997-01-22
Publication date: 1997-07-31
Also published as: DE69700548D1; DE69700548T2; AU1448897A; EP0876291A1; EP0876291B1

Abstract

A machine for making a packing/cushioning pad from a stack of paper sheets in a web (M) fed by a pair of vertically aligned wheels (8, 11) and joined together by a second pair of wheels (14, 17) after having been creased transversely between the two pairs of wheels (8, 11, 14, 17). The feed wheels (8, 11) rotate at a substantially higher speed than the joining wheels (14, 17) and thus cause transverse creasing of the material (M). The machine is provided with means for measuring the length of the resulting web of material (M), which means comprise a device (c, 40) for measuring the angular distance covered by one of the pairs of wheels (8, 11, 14, 17), and an electronic device (uc) for correcting the angular distance to be covered in order to give the actual resulting linear web length.

Description

Upholstery mattress making machine with product length measurement system

The present invention relates to machines for manufacturing a cushioning / padding material from a raw material consisting of a superposition of sheets of paper feeding them continuously, by driving and creasing said raw material, then assembling the 'crumpled by successive compressions, so as to form a padded band. The latter can then be sectioned into sections of variable length, according to subsequent needs.

In fact, these sections of padding material are used in particular for wedging products in cases, cartons, etc. on the one hand to prevent them from moving inside their packaging, and on the other hand in order to absorb any shocks applied against said packaging

Machines of this kind have been known in principle for a long time. Thus, in document US-A-3 603 216, the initial filing of which dates back to 1968, a machine is described in which a superposition of sheets of paper is guided in a hopper in the form of a trunk of a hoπzontal pyramid tapering towards the front so that the longitudinal edges of this stack of sheets are folded or rolled inwards, then between pairs of superimposed toothed wheels meshing together, so as to undergo on the one hand a ripple effect and d on the other hand an effect of crumpling, undulation and compression between each pair of teeth, which ensures an assembly of said stack of sheets folded back on themselves, the product leaving this machine being in the form of a "bead padded "with permanent cohesion, and suitable for wedging various articles in packaging

Each machine is generally equipped with at least one electric motor driving the strip of paper to be treated and most often with a second electric motor intended to actuate a cutting device placed at the downstream outlet.

These sectioning devices make it possible to obtain mattresses of a size suitable for subsequent use. To facilitate the task of the user, provision has been made to automate certain operations, and it is in particular provided that the choice of the appropriate dimensioning can be made in advance and repeated if necessary. US Patent No. 4,619,635 state of such a system assisting in automation, designed using a set of traditional electromechanical means cables and connected to the electric motor ensuring the advance of the strip of material These movens make it possible to adjust the period During the water engine in advance works by selecting said period oarmi jne plurality αe Deπoαes de temDS so that the operator no longer has to perform additional operations until the allotted time has elapsed. The section can then be cut.

According to this document, the activation of the cutting means also has the effect of automatically deactivating the advance motor, so that the product to be cut is static when it is cut. In addition, said motor is not reactivated before a certain period after the actual cutting, in order to allow the cutting means to return to their initial position.

The operator actually has adjustment buttons allowing to select a scale (seconds, minutes, hours), then the desired period in the chosen scale. The selection is therefore only made by adjusting the operating time.

This system, which certainly makes it possible to automate production to a certain extent, however has many disadvantages. The first, essential, is that what ultimately matters to the user is the length of strip produced, and that this does not necessarily correspond linearly to a predetermined period of advance of the drive motor. In other words, the function giving the length produced as a function of time is not linear, for many reasons, among which we can cite the quality of the paper, the external conditions (humidity, temperature, ... ), etc. Then, measuring time amounts to considerably complicating the very structure of the machine if the length produced is to be ensured in a substantially uniform manner from one machine to another. Conversely, not caring about it leads to very different operations of the same machines, depending on whether the advance motor is more or less fast, whether one operates at 50 Hz or 60 Hz (USA, Europe , ...), that the motors have different reaction curves at start-up, or even during operation, etc.

Machines with an automation system operating by time measurement therefore exhibit behaviors that are significantly different from one another, without it being possible to guarantee ranges of results for the same type of machine.

This is why, according to the present invention, to remedy the problems mentioned, provision has been made to measure the length of the strip of paper being processed, and no longer to measure time.

The mattress length produced is therefore always guaranteed, whether the engine is slow or fast, whether it operates at 50 Hz or 60 Hz, whether or not there are hard spots during the advance or start-up (in particular whether the coil is large or small), etc.

Whatever the quality of the components or the operating conditions, the uniformity of the results is guaranteed. This advantage is very important because '! mean that the manufacturer offers users great precision in use without resorting to complex and expensive technological solutions.

In the state of the art, machines have also been proposed equipped with time independent measurement systems. Thus, the PCT patent application referenced WO 95/13914 describes a device for measuring the length of the material produced by a machine of the aforementioned type, in the form of a disc placed at the end of a shaft connected to the engine. drive, provided on its periphery with a number of through holes, and which cooperates with an optical transceiver. The disc includes orifices distributed regularly over its periphery, and it is for example painted black, so as to be non-reflective. Indeed, the transceiver emits an axial light signal, which is reflected by a reflector placed in the axis of the transmitter, behind the disc, only when an orifice of said disc passes in front of the transceiver. A reception therefore corresponds to each reflection, which generates an impulse sent to a controller. This is used in the machine in question to measure the angular distance traveled, which can be transformed into a theoretical linear distance. However, this document is silent on the essential problem underlying this theoretical measure. The calculated distance is in fact not equal to the length of padded strip produced, due to the particular nature of the mattress, and in particular the differences in reaction of papers of different qualities, which are not treated in the same way during of the quilted bead forming process. The length of quilted strip produced is never equal to the horizontal projection of the measured angular length. Consequently, a device for measuring the length of padding strip produced cannot be limited to a device measuring the angular distance traveled by a shaft connected to the motor shaft.

Because of the intrinsic resilience of the strips, the problem of measuring their length is much more complex. In general, if it is advantageous to have a system for measuring the angular distance, as mentioned above, it is only in combination with other elements making it possible to resolve the specific problems.

The present invention therefore associates the device placed on the rotating shaft with specific circuits placed on a central processing unit, performing several particular functions, without which the information collected on the rotating shaft would provide incomplete data. These functions, as discussed, are not limited to lengths of calculations produced, but operate a necessary correction in order ^to achieve a measure of the actual length of the manufactured band. According to the invention, the machine for manufacturing a cushioning / padding material from a superposition of sheets of paper in a strip, driven by a pair of superimposed wheels, and assembled by a second pair of wheels, a crumpling transverse being provided between the two pairs of wheels because the drive wheels rotate substantially faster than the assembly wheels, thereby effecting a transverse crumpling of the material, is characterized in that it is provided with means for measuring the length of the tape produced comprising:

- a device for measuring the angular length traveled by one of the pairs of wheels,

- an electronic device operating a correction of the angular length to be covered in order to obtain the linear length of strip actually produced.

Until now, in the aforementioned prior art, only the device for measuring the angular length traveled by the rotary mechanism driving the padded strip existed, and not the control and adjustment device carrying out a correction in order to obtain a linear length. actual output of the machine.

These machines have mechanisms for driving, creasing and connecting the padded strip which are concentrated in a single rotary system, which is not the case with the machines of the present invention. The latter in fact comprise two sets of wheels which also rotate at different speeds, and are based on a crumpling and connection technique using transverse folds.

The existence of these folds, combined with the high resilience of the mattress produced, requires a correction of the measurement of the angular length to result in a measurement of the real linear length of the strip material produced.

This is true whatever the couple of wheels in which the angular length measuring device is integrated, only the calculation of the correction changing if the said device is moved from one set of wheels to another.

According to the invention, the electronic correction device comprises a central unit comprising a microprocessor and an EPROM type memory containing the processing program for said machine, said central unit being electrically connected to said angular length measuring device and comprising in memory the corrected value of the linear measurement of the strip to be produced, as well as electronic means of converting it into an angular measurement, an electronic connection sending an electrical advance signal to a motor controlling the advance of the strip material as long as said corrected measurement is not reached.

Depending on the quality of the paper used as well as the operating conditions, the adjustment of the actual linear length may however vary. The corrected value of the strip length to be produced is therefore variable according to the above criteria. This is why the machine of the invention further comprises a device allowing an operator to control and adjust the correction of the angular length, said device being connected to the central unit of the electronic correction device.

More specifically, this device, allowing an operator to control and adjust the correction of the angular length, consists of a keyboard and a display connected to the central processing unit, to transmit there the desired linear length of strip, as well as 'a basis for calculating the correction of the angular length, entered by the keyboard by said operator.

This basis for calculating the correction is in fact the value of the angular distance corresponding to the production of a unit of length of the padded strip. We therefore carry out a calibration measurement giving the previous value, which is stored in memory in the central unit. Thus, for each new quality of paper, and for given operating conditions (humidity, temperature, ...), the machine can be adapted so that the production of tape measured is not the simple horizontal projection of the angular length of the drive wheels.

Preferably, the device for measuring the theoretical angular length is a device placed on a rotating shaft when the strip of material is driven, transforming the angular movement of said shaft into electrical pulses.

According to a preferred possibility, said device is an incremental encoder. It is then placed on a shaft driven in rotation when the belt drive motor is activated.

As we have seen before, the accuracy of the measurement can be adjusted by modifying the number of pulses constituting a unit of measurement (cm, inch), in particular to take into account the different qualities of paper or the operating conditions. One can indeed have access, via the screen and the keyboard constituting the man / machine interface, to the address at which this number is stored.

The operation of such a machine can be done either in cm or in inches, either by using a double track encoder, or by using an encoder suitable only for one or the other of said measurement units, by simply proceeding installing the encoder that is suitable for the market in which the machine will operate, or alternatively changing in memory the value corresponding to a unit of production length of padded tape. Several values can also be stored in several locations in memory. According to a variant, the device transforming the angular movement of the motor shaft into electrical pulses can be an inductive proximity detector operating with at least one metallic element integral with the rotating shaft in movement when the padded strip is driven. In this case, said rotary element is for example of the screw type fixed on a flange of a fan secured to the rotary shaft, between the blades of said fan, at a radial distance from the shaft positioning it at each rotation opposite said proximity sensor. Most electric motors are equipped with fans, so it is easy to integrate such an angular measurement system. For the two aforementioned systems, the associated central unit comprises a comparator intended to compare on the one hand the number of pulses coming from the device for measuring the angular length traveled, and on the other hand the corrected number of pulses, and it also includes a means of calculating the number of pulses corrected, by multiplication of the desired linear length, entered by the keyboard by the user, and of the basis for calculating the correction, consisting of a number of pulses per linear unit length.

In other words, the number of pulses corresponding to the length to be produced is stored in a particular memory after calculation from two values coming from an external keyboard accessible to the user, giving on the one hand said length in units of length, and secondly the number of pulses per unit of length for a quality of raw material chosen, depending on the measurement system used (cm or inches), for given operating conditions.

In this solution, the device for measuring the padded strip produced, adapting to the constraints arising from the operation of the machine and from the nature of the raw material used, correctly measures the length of strip manufactured, due to the existence of values stored in memory and of a comparator circuit.

The invention also relates to a method for measuring the length of production of a material quilted into a strip comprising several layers of paper whose edges are folded longitudinally towards the center, the strip thus folded being driven by a pair of wheels and then assembled by a second pair of wheels, a transverse crumpling being ensured by the fact that the assembly wheels rotate faster than the drive wheels, characterized in that:

- the value of the angular distance traveled by one of said wheels when the length of the padded strip produced is equivalent to one unit of length is stored in memory in a central computing unit, at an address accessible to the operator via means adjustment and control,

- the desired length of quilted product is transformed into theoretical value of angular displacement by computer center, using the value stored in memory the measurement of the value of the angular displacement actually traveled by one of said wheels is carried out continuously using measurement means placed in the vicinity of said wheel, and transmitted in real time to said central unit, and

- the theoretical and measured values of the angular distance are compared, the displacement of the padded strip ceasing when equality is obtained.

In the case of the use of an incremental encoder or an inductive detector, the value of the angular distance traveled by one of said wheels, when the length of the padded strip produced is equivalent to a unit of length, corresponds to a certain number of pulses, measured then stored or modified in the memory of the central unit when the quality of the paper and / or the operating conditions change.

This particular method of calculating the length is justified by the fact that the linear length of padded strip produced does not correspond at all to the calculations of lengths traveled which can be made from the measurements carried out on the rotating members of the machine.

The invention will now be described in more detail, with reference to the appended figures, for which:

- Figure 1 is a top view of the apparatus according to the invention, with the sheets of paper in place. - Figure 2 is a vertical section through the longitudinal plane of symmetry of the device (ll-ll in Figure 1).

- Figure 3 is a vertical cross section through the axis of the drive wheels, along III-III of Figure 2.

- Figure 4 is a vertical cross section through the axis of the assembly wheels, along IV-IV of Figure 2.

- Figure 5 shows a simplified view of the man / machine interfacing device, namely the display / keyboard assembly.

- Figure 6 is a simplified block diagram of the general framework of the measurement operation of the length of strip produced. - Figure 7 is a schematic view of part of the cover of an electric motor, with fan and proximity sensor.

In these drawings, we find the usual elements of a machine for manufacturing cushioning / padding material from a stack of sheets of paper, namely, essentially, carried by a frame 1, at least one coil 2 of sheets of superimposed paper, a forming stage 3, drive, crumpling and compression members assembled in a cradle 4 and driven by a motor 5, a cutting system 6 and a front extraction chute 7.

The basic system allowing the folding of the longitudinal edges of the multi-layer strip appears more particularly in FIGS. 1 and 2. from the Dapier of ia reel 2 and in particular thanks to a guide system ensuring the folding of the longitudinal edges in a simple and effective manner.

This guide system mainly comprises a central plate 33 of substantially horizontal shape, around which the paper strip M is wound, by folding the longitudinal edges towards the running axis, guided in this by the wheels 31 and the metal rods 32, according to a configuration already known.

The encoder c, the first example illustrated, is mounted on the mechanical assembly assembled in the cradle 4, the various elements and the arrangement of which are shown in Figures 3-4. This assembly comprises a first pair of superimposed wheels (FIG. 3), namely an upper wheel or drive wheel 8 rotating on an axle 9 mounted in the lateral flanges 10-10 ′ of the cradle 4, and a lower support wheel 11, rotating on an axis 12 carried by lifting beams 13, 13 ′ mounted elastically tilting relative to the cradle 4, as described in more detail in patent EP 94440027.4 of the applicant.

The same mechanical assembly comprises a second pair of superimposed wheels (FIG. 4), namely an upper wheel or compression wheel 14, rotating on an axis 15 mounted in the lateral flanges 10, 10 'and driven in rotation by the motor 5, and a lower bearing wheel 17, rotating on an axis 18 also carried by the spreaders 13, 13 'mounted resiliently tilting relative to the cradle 4 via springs 26, 26'.

In the embodiment presented, the two axes 9 and 15 are positively driven by the motor 5, namely the axis 15 directly and the axis 9 via a reducing gear train shown schematically at 16â. 16b_, 16ς between FIGS. 3 and 4. The incremental encoder c is mounted on the axis 15, at the other end relative to the electric motor 5.

Briefly, the constitution and functions of these two pairs of wheels are as follows:

As shown in FIG. 3, the drive wheel 8 has a generally cylindrical appearance, with a central portion 19 in the form of a toric gutter with a substantially semi-circular section, and two end portions 20, 20 ′, each having a cylindrical periphery interrupted at regular intervals by flats 21, with the particularity that the flats 21 of the portion 20 face cylindrical zones 22 'of the portion 20', while conversely the flats 21 'of the portion 20' face cylindrical zones 22 of the portion 20.

Furthermore, the support wheel 11 with which the drive wheel 8 cooperates is in the form of a generally cylindrical shape but comprising in its median Dortiorr a toric bead 23, the raised section of which corresponds substantially to the cross section. hollow of the gutter αe -a wheel 8 The material M emerging from the hopper 3, and consisting of a stack of sheets of paper folded over on themselves, passes between the wheels 8 and 11, and is driven forward by the drive wheel 8, but with the following features: as shown in Figure 3, said strip of material M will be clamped with a variable force, on the support wheel 1 1, in the passage of the cylindrical zones 22, 22 'of the portions 20, 20', but will remain free to the passage of the flats 21, 21 '. Because of the offset between the flats of the two portions 20, 20 ′, the strip M will therefore be driven alternately on each side of its longitudinal central axis, instead of being pulled only axially with the tear generating forces which would result therefrom. This advancement by successive jerks from one side to the other makes it possible to have in the center a surplus of paper compared to its planar configuration, this surplus being generated by the bead 23 sinking into the gutter 19, which will allow improved crumpling.

Referring now to FIG. 4, the compression wheel 14 has a generally cylindrical appearance and comprises two portions of crenellated ends 24, 24 ′ joined by a neutral central portion 25; moreover, the support wheel 17 is a smooth cylinder on which the grooves 24, 24 "will roll. The strip material M, coming from the first pair of wheels 8/11, is clamped between said grooves 24, 24 'and this smooth surface, with a variable force, this compression is limited, however, and cannot damage said material, since the latter is not deformed between gear teeth meshing with one another as in previous systems. , 24 ′ on the material is therefore to ensure by this simple compression, the assembly of the sheets of said material and the cohesion of this assembly, by crushing the folds of the paper. Finally, the crumpling function is fulfilled by a purely mechanical phenomenon n not affecting the strength of the material.

To this end, as symbolically suggested by the schematic representation of the pinions 16a, 16b, 16c forming a reduction gear between FIGS. 3 and 4, ie motor 5, driving the wheel 14, also drives the wheel 8, in the same direction, but at higher speed. It follows that the strip of material M leaving the pair of wheels 8-1 1 will be taken up at a lower speed by the pair of wheels 14-17. Consequently, the material will settle between these two pairs of wheels, permanently creating a series of transverse folds, designated by P in FIG. 2. The crumpling function of the material M is therefore fulfilled by this difference in rotational speed of the two pairs of wheels, the drive torque 8. 11 rotating faster than the assembly torque 14. 17. Experience has shown that a gear ratio of the order of 1 .9 leads to the best results . This can be obtained for example with the sprockets 16a and 16b of 20 teeth and an onion 16c with 38 teeth, it being understood that the onion 16b has no other role of ensuring that the pinion 16c, therefore the wheel 14, has the same direction of rotation as the pinion 16a, that is to say the wheel 8.

As mentioned, the incremental encoder is housed at the end of the shaft 15 (see Figures 1 and 4), opposite the toothed wheel 16c, and therefore the motor 5. It is fixed in a bore in the end of said shaft 15, in which an external shaft of said encoder c fits, in a manner known per se, using a screw for fixing the internal ring of the bearing situated at this end, which is applied against the outer shaft of the encoder c like a needle. This screw consequently crosses radially the whole non-bored part of the shaft 15, and must be provided more elongated than if it were only intended to fix said internal ring on the shaft 15.

The encoder c is connected via a cable e to the electronic card forming the central unit, to which it sends the pulses necessary for counting, and from which it receives the operating voltage. In the lower part of FIG. 4, a very schematic representation of the principle of measuring the length of strip produced is shown. The purpose of this representation is to show that there is a comparison which is made between on the one hand the theoretical value of the length, as entered by the user via the keyboard k and transformed into a number n of pulses. by the correction carried out in the central processing unit uc, and on the other hand the value measured in real time at the output of the incremental encoder c.

When there is equality between the two values, the advance motor is stopped automatically, which is shown diagrammatically by the switch s placed for the purposes of the explanation at the output of the comparator. Of course, the exact operation is that which has already been mentioned, namely centralized management by a microprocessor and an EPROM, which carry out the comparison and manage the advance motor. It is therefore in reality a program operation. , and not based on discrete components, used to clarify the explanation, and which could be the subject of a variant of the device of the invention FIG. 5 shows a detail of an example of an external box allowing the operator to communicate with the machine, and comprising for this purpose a keyboard k, a display a, and an LED r whose state reflects the powering up of the assembly.

In addition to the numeric keys, this keyboard has literal keys (S, E) which are used to select the possible operating modes, by means of the S key, and their validation by the E key. The different modes scroll sequentially and allow, to with the help of messages appearing on the display a, to enter on the keypad k the information necessary for the central panel to operate the machine The accuracy of the measurement can also be adapted to the operating conditions or the quality of the paper. Indeed, depending on the resolution of the incremental encoder chosen, the number of pulses corresponding to a unit of measurement can be calibrated, whether this is cm or inch in Anglo-Saxon countries. Thus, it has been measured that if the resolution of the encoder is 1024 pulses per revolution, 31 pulses correspond to one cm. This number is accessible to the user via the keyboard k and the display a, and he can modify it as he pleases. Lower quality paper, for example, will come out of the two sets of wheels more compressed longitudinally, and will require an adjustment of this number, reduced to 30 or 29. The fact of going from 30 to 31 corresponds to a difference of approximately

1 mm.

The same adjustment can of course be made to resize a machine operating in inches. This adjustment is instantaneous via the user interface, and only requires a check on the quilted product produced. The articulation of this adjustment phase with the rest of the operation of the measurement operation of the length of strip produced appears in FIG. 6, which is a simplified block diagram of said operation. This figure illustrates more particularly the methodology used by the program resident in EPROM, without entering into the details relating to the addresses for storing the values, or communicating the detailed programs, which are within the competence of those skilled in the art. When the theoretical value is equal to the measured value, a signal is sent by the central processing unit uc to the address of the advance motor, to make it stop.

FIG. 7 shows the fixing of an inductive proximity detector 40 on the cover 41 of an engine, controlling the advance of the padded strip M. The detector 40 is located on the periphery of the cover, so as to be close at least one element 38 fixed between the blades 42 of the fan 43 generally placed at the end of the shaft for an electric motor. Preferably, said element 38 may be a screw fixed in a thread in the flange 39 of the fan 43. In this side view, the relative positioning of element 38 / detector is particularly clearly seen, as well as the possibility of adjusting the distance allowing the operation detector 40.

Thus, the cover 41 has an opening 34 opening access to an internal nut 35, allowing in combination with an external nut 36 simultaneously the tightening of the sensor 40 and its position adjustment relative to the elements 38 of the fan 43. The distance d . must obviously be able to be adjusted with a fairly high degree of precision, so as to allow correct operation of the Droximity 40 detector.

This one has a sensitivity such that it allows it, if it is correctly positioned, to detect the oassay at the J2 jaloes of the ventilator - i3 icsa which they proximity to its inner end; however, with the detection devices chosen, this is only true if said blades 42 include metal detectable by the sensor 40. The fans are generally made of aluminum, but it has been found that the most common detectors work better if at least one additional metallic element 38 is fixed to the fan 43.

For example, two iron or steel screws are fixed, opposite one another on the flange 39, and the detector is positioned so that two detections per revolution are carried out. The inductive proximity sensor then emits two pulses per revolution, processed by an electronic circuit located on the central unit uc, which performs the same function as for the encoder c. This electronic circuit is connected to the detector 40 via a cable 37 appearing in FIG. 7, and connected to a terminal block of said circuit or of the central processing unit uc.

For the measurement of the length of padded strip produced, the detector is placed on the feed motor referenced 5 in FIG. 1. The signal is sent directly to the central unit uc, which counts the pulses sent by the detector 40, and the processes to measure said length, as a function of stored data, such as the number of pulses corresponding to a unit of length for the quality of paper used and the length to be produced. The simplified block diagram of the operation is the same as in operation with the incremental encoder.

Claims

1. Machine for the production of a cushioning / padding material from a superposition of sheets of paper in strip M driven by a pair of superimposed wheels 8, 1 1 and assembled by a second pair of wheels 14, 17, a transverse crumpling being ensured between the two pairs of wheels 8, 11, 14, 17, because the drive wheels 8, 1 1 rotate substantially faster than the assembly wheels 14, 17, thus effecting a transverse crumpling of the material M, characterized in that it is provided with means for measuring the length of the strip of material M produced comprising:

a device c, 40 for measuring the angular length traveled by one of the pairs of wheels 8, 11, 14, 17,

- an electronic device uc operating a correction of the angular length to be covered in order to obtain the linear length of strip actually produced.

2. Machine for manufacturing a cushioning / padding material according to claim 1, characterized in that said electronic correction device comprises a central processing unit uc comprising a microprocessor and an EPROM type memory containing the processing program of said machine , said central unit uc being electrically connected e, 37 to said angular length measuring device c, 40 and having in memory the corrected value of the linear measurement of band M to be produced, as well as electronic means of converting it into a measurement angular, an electronic connection S sending an electrical advance signal to a motor 5 controlling the advance of the material in strip M as long as said corrected measurement is not reached.

3. Machine for manufacturing a cushioning / padding material according to claim 2, characterized in that it comprises a device (a, k) allowing an operator to control and adjust the correction of the angular length, said device being connected to the central processing unit uc of the electronic correction device.

4. Machine for manufacturing a cushioning / padding material according to claim 3, characterized in that the device allowing an operator to control and adjust the correction of the angular width consists of a keyboard K and a display connected uc to ^Central jπté of processing, to transmit therein the desired linear strip length and a basis for calculating the correction of the angular length, entered on the keyboard k by said operator.

5. Machine for manufacturing a cushioning / padding material according to any one of the preceding claims, characterized in that the device c for measuring the theoretical angular length is a device placed on a shaft 15 in rotation when the strip of material M is driven, transforming the angular movement of said shaft 15 into electrical pulses.

6. Machine for manufacturing a cushioning / padding material according to the preceding claim, characterized in that said device is an incremental encoder c.

7 Machine for manufacturing a cushioning / padding material according to one of claims 2 to 6, characterized in that the incremental encoder c is a double track, allowing measurements to be made in centimeters or inches.

8. Machine for manufacturing a cushioning / padding material according to one of claims 1 to 4, characterized in that the device for measuring the theoretical angular length is an inductive proximity sensor 40 operating with at least one element metal 38 secured to a rotating shaft when the strip M is driven

9. Machine for manufacturing a cushioning / padding material according to claim 8, characterized in that said metal element is of screw type 38 fixed on a flange 39 of a fan 43 secured to the rotary shaft, between the blades 42 of said fan 43, at a radial distance from the shaft positioning it at each rotation opposite said proximity detector 40.

10. Machine for manufacturing a cushioning / padding material according to one of claims 5 to 9, characterized in that the central unit uc comprises a comparator intended to compare on the one hand the number of pulses from the device for measuring the angular length c, 40 traveled, and on the other hand the corrected number of pulses, as well as a means of calculating the corrected number of pulses, by multiplying the desired linear length, input to the keyboard k by the user, and the basis for calculating the correction consisting of a number of pulses per linear unit of length 11. Method for measuring the linear length of cushioning / padding material produced by a machine for the manufacture of such a material from a superposition of sheets of paper in M-band driven by a pair of superimposed wheels 8, 1 1 and assembled by a second pair of wheels 14, 17, a transverse crumpling being ensured between the two pairs of wheels 8, 11, 14, 17 because the drive wheels 8, 1 1 rotate substantially faster than the wheels of assembly 14, 17, thus managing a transverse crumpling of the material M, characterized in that:

- the value of the angular distance traveled by one of said wheels 8, 11, 14, 17 when the length of the padded strip M produced is equivalent to a unit of length is stored in memory in a central computing unit uc, at a address accessible to the operator, via adjustment and control means (a, k),

the linear length of padded strip M to be produced is transformed into theoretical value of angular displacement by the central processing unit uc, using said value stored in memory,

the measurement of the value of the angular displacement actually traveled by one of said wheels 8, 11, 14, 17 is carried out continuously using measuring means placed in the vicinity of said wheel 8,

11, 14, 17, and transmitted in real time to said central processing unit uc, and

- The theoretical and measured values of the angular distance are compared, the movement of the padded strip M being stopped when equality is obtained.

12. Measuring method according to the preceding claim, characterized in that the measuring means consist of an incremental encoder c transforming the rotary movement of a shaft 15 in rotation when the padded strip M is driven in electrical pulses transmitted to the central unit uc.

13. Measuring method according to claim 11, characterized in that the measuring means consist of an inductive proximity detector transforming the rotary movement of an element 38 secured to a rotating shaft when the padded strip is driven in pulses electric transmitted to the central unit uc, each time said element 38 passes in front of said detector 40.

14. Measuring method according to one of claims' ^* to 13, characterized in that the value of the angular distance Darcourue oar one said wheels 8, 11, 14, 17, when the length of the padded strip produced is equivalent to a unit of length, corresponds to a certain number of pulses, measured then stored or modified in the central processing unit uc when the quality of the paper and / or the operating conditions change.