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

p0001cushioning pad manufacturing machine mattress length measuring system product

p0002The present invention concerns machines for producing a wedging / padding material from a starting material consisting of a superposition of sheets of paper feeding them continuously by drive and wrinkling of said first material, and then assembling the all wrinkled by successive cuts to form a padded band. The latter may then be cut into sections of varying length, according to future needs.

p0003In fact, these cushioning material sections are especially used to wedge product in boxes, cartons, etc. one hand to prevent it from moving inside the packaging, and secondly in order to absorb possible shocks applied against said packages

p0004These types of machines are known in principle for a long time. Thus, in US-A-3,603,216, the initial deposit was in 1968, is described a machine wherein a stack of sheets of paper is guided into a funnel-shaped hoπzontale truncated pyramid tapering towards the before so that the longitudinal edges of the stack of sheets are folded or rolled inwardly and between pairs of superposed gears meshed with each other, so as to undergo one hand a driving effect and secondly wrinkling effect of waves and compression between each pair of teeth, which provides an assembly of said stack of sheets folded back onto themselves, the product leaving this machine is in the form of a "bead padded "with permanent cohesion, and suitable for calibration of various items in packaging

p0005Each machine is generally equipped with at least one electric motor driving the paper web to be treated and usually a second electric motor for actuating a cutting device positioned downstream outlet

p0006These devices allow the cutting size mattress obtaining appropnée subsequent use. For the convenience of the user, are provided to automate certain operations, and it is particularly intended that the choice of suitable sizing can be done in advance or repeated if necessary US Patent No. 4,619,635 is state of such a system helping to automation, designed with a set of traditional electromechanical means cables and subsequently assembled with the electric motor providing advance of these movens material strip to adjust the period Dendant the aquelle α'avance engine works by selecting the said period oarmi jne ae Deπoαes plurality of temDS so the operator no longer has to perform additional operations until the allotted time has elapsed. The section of the cut can then take place.

p0007According to this document, the activation of the cutting means has in addition to effect the automatic deactivation of the feed motor, so that the product to cut is static when cut. Moreover, said motor is not reactivated until some time after the actual cutting, to allow cutting means to return to their original position.

p0008The operator has actually knobs for selecting a scale (seconds, minutes, hours) and the desired period in the selected scale. Selection is therefore only by adjusting the operating time.

p0009This system, though allowing to automate to some extent the production, however, has many drawbacks. The first essential is that what ultimately matters to the user is the length of strip produced, and that it does not necessarily linearly corresponds to an advance period of the predetermined drive motor. In other words, the function giving the length produced over time has no linear character, for many reasons, among which we can mention the paper quality, external conditions (humidity, temperature, ... ), etc. Then measure the time comes to considerably complicate the structure of the machine if you want the length produced is ensured in a substantially uniform manner from one machine to another. Conversely, do not worry about it leads to very different operations of the same machines, depending on whether the feed motor is more or less rapidly, which operates in 50 Hz or 60 Hz (USA, Europe , ...), that the motors have different response curves start, or even during operation, etc.

p0010Machines with an automation system operates by measuring the time therefore exhibit behavior significantly different from each other, without being able to guarantee the range of results for the same type of machine.

p0011Therefore, according to the present invention to remedy the problems mentioned, it was planned to carry out a measurement of the length of the paper web being processed, and not to a time measurement.

p0012The length of the mattress produced is therefore always guaranteed that the engine is slow or fast, it runs at 50 Hz or 60 Hz, whether or not hard points in advance or at startup (including due to the fact that the coil is large or small), etc.

p0013Whatever the quality of the components or the operating conditions, the consistency of results is guaranteed. This advantage is because αeterminant '! means the manufacturer offers users high accuracy for use without the need for complex and costly technological solutions.

p0014In the prior art, it has also been proposed machines with independent measuring systems of the time. Thus, PCT patent application referenced WO 95/13914 refers to a length measuring device 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 motor of training provided on its periphery with a number of orifices therethrough and which cooperates with an optical transmitter and receiver. The disc comprises orifices regularly distributed over its periphery, and it is for example painted black, so as to be nonreflective. Indeed, the transceiver transmits an axial light signal, which is reflected by a reflector located in the axis of the transmitter, behind the disc, only one port of said disk passes in front of the transceiver. Each reflection is therefore a reception, which generates a pulse 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. This document is however silent on the key issue underlying this theoretical measure. The calculated distance is indeed not equal to the padded band length produced, due to the particular nature of the mattress, including differences of different quality papers reaction, which are not treated in the same way in the forming process of the padded bead. The padded strip length produced is never equal to the horizontal projection of the angular length measured. Therefore, a device for measuring the tape length of padding produced can be limited to a device measuring the angular distance traveled by a shaft connected to the motor shaft.

p0015Due to the intrinsic resilience of the bands, the problem of the measurement of the length is much more complex. In general, it is advantageous to have a system for measuring the angular distance, as mentioned above, it is only in combination with other elements to solve specifically the problems posed.

p0016The present invention therefore combines the device placed on the rotating shaft to specific circuits placed on a central processing unit, making several special functions without which the information gathered on the rotating shaft provide incomplete data. These functions, as we shall see, are not restricted to the produced length calculations, but operating a necessary correction, to^'produce a measure of the actual length of the manufactured strip. According to the invention, the machine for the manufacture of a wedging / padding material from a superposition of sheets of paper strip, driven by a pair of superposed wheels and assembled by a second pair of wheels, a rustling transverse being ensured between the two pairs of wheels because the drive wheels rotate substantially faster than the assembling wheels, thus making a transversal crumpling of the material, is characterized in that it is provided with means for measuring the length the band produced comprising:

p0017- A device for measuring the angular length covered by one of the pairs of wheels,

p0018- An electronic device by correcting the angular length to go for the linear length actually produced tape.

p0019So far in the aforementioned prior art only existed the device for measuring angular length traveled by the rotary mechanism driving the padded band, not controlling and regulating device making a correction to obtain a linear length actual output of the machine.

p0020These machines are equipped with drive mechanisms, crumpling and connecting the padded band which are concentrated in a single rotating system, which is not the case of machines of the present invention. Provided these are in fact two sets of wheels which rotate in addition to different rates, and is based on a technique of creasing and connection using transverse folds.

p0021The existence of these folds, combined with the resilience of the mat product, requires a correction of the measurement of the angular length to produce a measure of the actual linear length of strip material produced.

p0022This is true regardless of the torque wheel which is integrated device for measuring the angular length, only the calculation of the correction changing if moving said device to a set of wheels to the other

p0023According to the invention, the correction device comprises an electronic central unit including a microprocessor and an EPROM type memory containing the processing program for said machine, said central unit being connected électnquement said device for measuring the angular length and comprising memory the corrected value of the strip to produce linear, as well as electronic means to convert it into an angular measurement, an electronic connection sending an electrical feed signal to a motor controlling the advance of the strip material as long as said corrected measurement is not reached.

p0024Depending on the quality paper used and the ODératoires conditions the adjustment of the actual linear length can ceoendant vaπer The corrected value of the tape length to produce thus varies according to the above criteria. Therefore, the machine of the invention further comprises a device allowing an operator to control and set the correction of the angular length, said device being connected to the central unit of correcting electronic device.

p0025Specifically, this device allows an operator to control and adjust the correction of angular length, consists of a keyboard and a display connected to the central processing unit, to transmit the linear length of desired band, as well as a base of calculation of the correction of the angular length, entered on the keyboard by said operator.

p0026This basic calculation of the correction is actually the value of the angular distance corresponding to the production of a length of the padded tape drive. therefore carried out a calibration measurement giving the previous value, the memory is stored in the CPU. Thus, for each new paper quality, and for given operating conditions (humidity, temperature, ...), we can adjust the machine so that production measured band is not the simple horizontal projection the angular length of the drive wheels.

p0027Preferably, the device for measuring the theoretical angular length is a device positioned on a rotating shaft when the material web is driven, transforming the angular movement of said shaft into electrical pulses.

p0028According to a preferred configuration, said device is an incremental encoder. It is then placed on a rotatably driven shaft when the tape drive motor is actuated.

p0029As noted previously, the measurement accuracy can be adjusted by changing the number of pulses constituting a measurement unit (cm, inch), in particular to take account of the different qualities of paper or operating conditions. One can indeed access through the screen and the keyboard constituting the human / machine interface at the address at which is stored the number.

p0030The operation of such a machine can be indifferently in cm or inch, or by using a double track encoder, or by using an encoder adapted only for one or for the other of said measurement units, simply by following the installation of the encoder suitable for the market in which the machine will work, or by changing the stored value corresponding to a unit of padded belt length production. Multiple values ​​can also be stored in multiple locations in memory. According to a variant, the device transforming the angular movement of the drive shaft into electrical pulses can be an inductive proximity sensor operating with at least one metal element integral with a rotary shaft moving when the padded web is driven. In this case, said rotary member is for example of the screw type fixed on a flange of a fan integral with the rotary shaft, between the blades of said fan, at a radial distance from the shaft placing it at each rotation in front of said proximity sensor. Most electric motors are equipped with fans, it is easy to integrate such angular measurement system. For the above systems, the associated central processing unit includes a comparator for comparing firstly the number of pulses from the device for measuring the angular length covered, and secondly the corrected number of pulses, and it also includes means for calculating the corrected number of pulses, by multiplying the required linear length, entered on the keypad by the user, and the basis for calculating the correction, consisting of a number of pulses per linear unit length.

p0031In other words, the number of pulses corresponding to the length to be produced is stored in a particular memory after calculation from two values ​​from an external key accessible to the user, giving the one hand said length units of length, and secondly the number of pulses per unit of length for a quality raw material selected, depending on the measuring system used, (cm or inches), for given operating conditions.

p0032In this solution, the measuring device of the padded web produced, adapting to constraints based on operation of the machine and the nature of the feedstock used, correctly measures the length of strip produced, due to the existence of values ​​stored in memory and a comparator circuit.

p0033The invention also relates to a method for measuring the length of producing a strip padded material comprising several layers of paper, the edges are folded towards the center longitudmalement, the thus folded strip being driven by a pair of wheels and assembled by a second pair of wheels a transversal crumpling being ensured by the fact that the connecting wheels rotate faster than the driving wheels, characterized in that:

p0034- The value of the angular distance covered by one of said wheels when the length of padded web produced is equivalent to a unit of length is stored in memory in a central computer unit has an accessible address to the operator via means adjustment and control,

p0035- The desired product length padded turned into theoretical value of angular displacement central computing has help ae laσite value stored in memory - Measuring the value of the angular displacement really covered by one of said wheels is carried out continuously using measuring means placed in the vicinity of said wheel, and transmitted in real time to said central unit, and

p0036- The theoretical and measured values ​​of the angular distance are compared, the travel of the padded web ceases when equality is achieved.

p0037In the case of the use of an incremental encoder or an inductive sensor, the value of the angular distance covered by one of said wheels, when the length of padded web produced is equivalent to a unit of length, corresponds to a number of pulses, measured and stored or modified in the memory of the CPU when the paper quality and / or the operating conditions change.

p0038This particular method of calculating the length is justified by the fact that the linear length of padded band produced does not correspond at all to the lengths traveled calculations that can be done from measurements on rotating parts of the machine.

p0039We will now describe the invention in more detail, with reference to the appended figures, in which:

p0040- Figure 1 is a top view of the apparatus according to the invention with sheets of paper in place. - Figure 2 is a vertical section through the longitudinal plane of symmetry of the unit (II-II on Figure 1).

p0041- Figure 3 is a transverse vertical section through the axis of the drive wheels, along line III-III of Figure 2.

p0042- Figure 4 is a transverse vertical section through the axis of the wheel assembly, along line IV-IV of Figure 2.

p0043- Figure 5 shows a simplified view of the interface device human / machine, namely the display / keypad.

p0044- Figure 6 is a simplified block diagram of the general framework of the operation of measuring the length of strip produced. - Figure 7 is a schematic view of a portion of the cover of an electric motor with fan and proximity sensor.

p0045In these drawings, there are the conventional elements of a cushioning material manufacturing machine / padding from a stack of paper sheets, i.e., essentially, carried by a frame 1, at least a reel 2 leaves of superposed paper, a forming stage 3 of the drive members, crumpling and compression together in a cradle 4 and driven by a motor 5, a cutting device 6 and an extraction duct 7 from the front.

p0046The basic system for the withdrawal of the longitudinal edges of the multicoucne band appears particularly in Figures 1 and 2. from Dapier of ia Reel 2 and thanks to a guidance system ensuring the withdrawal of the longitudinal edges of simple and effective way.

p0047This guidance system mainly comprises a central plate 33 substantially horizontal shape, around which the paper web M is wound, by folding the longitudinal edges to the axis of movement, guided in this by the wheels 31 and metal rods 32, according to a known configuration.

p0048The encoder c, the first example shown, is mounted on the mechanically assembled together in the cradle 4, in which the various elements and the arrangement are shown in Figures 3-4. This assembly comprises a first pair of superposed wheels (Figure 3), namely a rotating upper wheel or drive wheel 8 on a shaft 9 mounted in the side plates 10-10 'of the cradle 4, and a lower support wheel 11, rotating on an axis 12 supported by the lifting beams 13, 13 'resiliently pivoting mounted relative to the cradle 4, as described in more detail in EP 94440027.4 of the applicant.

p0049The same mechanical assembly comprises a second pair of superimposed wheels (Figure 4), namely an upper wheel or compressor wheel 14, rotating on an axis 15 mounted in the side plates 10, 10 'and rotated by the motor 5, and a lower support wheel 17 rotating on an axis 18 also carried by the lifting beams 13, 13 'resiliently mounted pivoting relative to the cradle 4 through the springs 26, 26'.

p0050In the embodiment shown, the two shafts 9 and 15 are positively driven by the motor 5, namely the shaft 15 directly and the axle 9 via a reduction gear train shown schematically at 16a. 16b_, 16ς between Figures 3 and 4. The incremental encoder c is mounted on the shaft 15 at the other end relative to the electric motor 5.

p0051Briefly, the constitution and functions of the two pairs of wheels are:

p0052As shown in Figure 3, the drive wheel 8 is generally cylindrical, with a central portion 19 shaped annular gutter section substantially semicircular, and two end portions 20, 20 ', each having a cylindrical periphery regularly interrupted by the flats 21, with the particularity that the flats 21 of the portion 20 are facing cylindrical surfaces 22 'ia portion 20', while conversely the flat portions 21 'of portion 20' face cylindrical areas 22 of the portion 20.

p0053Furthermore, the support wheel 11 which cooperates with the driving wheel 8 is in a form generally cylindrical but having in its median Dortiorr a bead ring 23, the relief sectior substantially corresponds to the section hollow gutter ring ae -a wheel 8 The hopper H of the outgoing material 3 and consisting of a stack of sheets of paper folded over themselves, pass 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 material M band will be clamped with a variable force on the supporting wheel 1 1 passing cylindrical zones 22, 22 'of the portions 20, 20', but remain free passage of the flats 21, 21 '. Due to the mismatch between the flats of the two portions 20, 20 ', M band will be alternately driven either side of its central longitudinal axis, instead of being pulled only axially with the tear generating efforts that result. This advancement by successive jolts from side to the other allows to have at the center a surplus of paper with respect to its flat configuration, this surplus being generated by the bead 23 being inserted in the groove 19, which enable improved creasing.

p0054If reference is now made to Figure 4, the compression wheel 14 is generally cylindrical and includes two end portions crenellated 24, 24 'joined by a neutral middle portion 25; Moreover, the support wheel 17 is a smooth cylinder on which will roll the splines 24, 24 ". The strip material M, from the first pair of wheels 8/11, is clamped between said splines 24, 24 'and this smooth, with variable force. this compression is limited and can not damage the said material, since it is not deformed between gear tooth meshing together as in previous systems. the action of the grooves 24 24 'on the material is thus to ensure that by simple compression, assembling sheets of said material and the cohesion of the assembly, by crushing the folds of paper. Finally, the crumpling function is performed by a purely mechanical phenomenon n 'not affecting the strength of the material.

p0055For this purpose, as symbolically suggested by the schematic representation of the pinions 16a, 16b, 16c forming a gear train between Figures 3 and 4, ie motor 5, driving the wheel 14, also drives the wheel 8, in the same direction, but at higher speed. As a result, the M strip of material leaving the wheel torque 8-1 1 will be restarted at a lower speed by the pair of wheels 14-17. Therefore, the material will settle between these two pairs of wheels, creating permanently a series of transverse folds, designated by P in Figure 2. The function of crumpling of the material M is thus met by this rotational speed difference two pairs of wheels, the drive torque 8. 11 rotating faster than the assembly torque 14. 17. experience has shown that a ratio of about 1 .9 speeds led to the best results . This can be achieved for example with αes pinions 16a and 16b of teeth 20 and teeth 16c onion ae 38, it being understood αue .e onion 16b has no role to ensure that the pinion 16c, and therefore to the wheel 14 the same direction of rotation as the pinion 16a, that is to say the wheel 8.

p0056As mentioned, the incremental encoder is mounted in the shaft end 15 (see Figures 1 and 4), opposite to the gear 16c, and therefore the motor 5. It is secured in a bore made in the end of said shaft 15, which fits an outer shaft said encoder c, of a per se known manner using a fastening screw of the inner ring of the bearing situated at this end, which bears against the outer shaft encoder c in the manner of a punch. This screw therefore passes radially all non bored portion of the shaft 15, and must be provided more elongated than if it were only intended to fix said inner ring on the shaft 15.

p0057C encoder is connected via a cable to an electronic card forming the central unit, which sends the necessary impetus to the count, and she receives the operating voltage. In the lower part of Figure 4, a highly schematic representation of the principle of the measurement of the strip length produced is represented. This representation is intended 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 converted into a number n of pulses by the correction made in the central unit uc, and secondly the value measured in real-time output of incremental encoder c.

p0058When there is equality between the two values, the feed motor is stopped automatically, which is shown schematically by the switch s placed for purposes of explanation in the comparator output. Of course, the exact function is the one we have already mentioned, namely centrally managed by a microprocessor and an EPROM, which perform the comparison and manage the advance II engine is therefore in reality a program operation , not based on discrete components, used to clarify the explanation, which could be a variant of the device of the invention Figure 5 shows a detail of an exemplary outer housing allowing the operator to communicate with the machine, and with this purpose a key k, has a display and a LED r whose status reflects the power of the whole.

p0059In addition to the numeric keys, this keyboard contains literal keys (S, E) are used to select operating modes, via the S key, and validation by the E key The different mode switches sequentially and allow at using messages appearing on the display has to key in your k necessary information has central jπte to operate the machine The accuracy of the measurement can moreover be adapted to the operating conditions or the paper quality. According to the resolution of the incremental encoder chosen, you can calibrate the number of pulses corresponding to a unit of measurement that it either cm or inches in Anglo-Saxon countries. Thus, it was measured that if the encoder resolution is 1024 pulses per revolution, 31 pulses correspond to a cm. This number is available to the user via the keyboard and the display k a, and may modify it at will. A paper released lower quality such as two sets of wheels longitudinally compressed more, and require an adjustment of that number reduced to 30 or 29. The placing of 30 to 31 corresponds to a difference of approximately

p00601 mm.

p0061The same adjustment can of course be made to reschedule a machine operating in inches. This setting is instant via the user interface, and requires only a check on the quilted product produced. The articulation of this adjustment phase with the rest of the operation of the operation for measuring the strip length produced appears in Figure 6, which is a simplified block diagram of the operation. This figure particularly illustrates the methodology used by the resident program EPROM, without going into details of the values ​​storage addresses nor disclose detailed plans, which are the purview of the skilled artisan. Where the design value is equal to the measured value, a signal is sent by the central unit uc at the feed motor to stop doing.

p00627 shows the fixing of an inductive proximity switch 40 on the cap 41 of a motor, controlling the advance of the padded band M. The detector 40 is located on the periphery of the cover so as to be close at least an element 38 fixed between the blades 42 of the fan 43 usually placed in the shaft extension for an electric motor. Preferably, said element 38 may be a screw fixed into a threaded bore of the flange 39 of the fan 43. In this side view, it is particularly clear relative positioning element 38 / detector, and the distance adjustment possibility for the operation optimal detector 40.

p0063Thus, the cover 41 includes an opening 34 providing access to an internal nut 35, allowing in combination with an external nut 36 simultaneously clamping the sensor 40 and its relative position adjusting members 38 to the fan 43. The distance d . must obviously be adjusted with a relatively high accuracy, so as to allow correct operation of the detector 40 Droximité.

p0064It has a sensitivity such αu'elle allows it, if cαrectement oositionne to αetecter ie oassaαe αes oales J2 -i3 icsαu'elles oassent fan Near its inner end; however, with the selected sensing devices, this is true only if said blades 42 have the metal detectable by the sensor 40. The fans are usually aluminum, but it turned out that the most common detectors work best if at least one additional metal element 38 is fixed to the fan 43.

p0065is fixed, for example two screws of iron or steel, as opposed to each other on the flange 39, and the detector is positioned so that two detections per turn are operated. The inductive proximity sensor then emits two pulses per turn, treated with a localized electronic circuit on the cpu CPU, which performs the same function as the encoder c. This electronic circuit is connected to the detector 40 via a cable 37 shown in Figure 7, and connected to a terminal of said circuit or uc CPU.

p0066To measure padded band length produced, the detector is placed on the engine beforehand referenced 5 in Figure 1. The signal is sent directly to the central unit uc, which counts the pulses sent by the detector 40, and trafficking for measuring 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 in operation with the incremental encoder.