EP1080012B1 - Device for setting sleeves on objects moving past - Google Patents

Abstract

The invention relates to apparatus for placing sleeves on conveyed articles, said sleeves being cut-off from a continuous sheath (13) passing over a floating type sheath-opening shaper (20). According to the invention, the wheels (30, 31) for lowering the sheath and the wheels (32, 33) for ejecting the cut-off sheath segment (15) are rotated by associated electric motors (41; 42, 43) controlled synchronously by a common electronic programmer (50) arranged to determine a continuous profile of speed variation so as to control the lowering of each sheath segment, said programmer including at least one control card (55) which co-operates with an adjacent encoder (47) mounted at the end of a shaft (46) rotated by a central motor and gearbox unit (40, 45). The synchronization obtained makes it possible to envisage very high rates of throughput while using sleeves of a diameter that is hardly greater than the maximum diameter of the articles.

Description

The present invention relates to the installation chons, in particular heat shrink sleeves scrolling objects, objects coated with sleeve then passing through a shrink oven

For fitting heat shrink sleeves scrolling objects, we conventionally use a technique whereby the sleeves are cut to size from a continuous sheath passing over a conformator sheath opening, which is kept floating by cooperation between external rollers and counter-rollers parallel axes carried by the shaper, which outer rollers ensure the advance of the sheath along the conformator in general vertical up to a medium cutting.

For the technological background, we can by example refer to documents EP-A-0 368 663, EP-A-0 366 267, EP-A-0 048 656, US-A-4 565 592 and JP-A-57 36612.

This general approach has in some cases been supplemented by the presence of second rollers provided downstream cutting means to eject the cut sheath section on the object which is brought opposite the conformator by a means of conveying step by step objects. We then find first outer rollers intended to ensure the advance of the sheath on the former, and second rollers used to eject the section of sheath cut on the object concerned. All these outer rollers are good heard motorized, and their motorization gave rise to several types of arrangements.

According to a first type of arrangement, it has been proposed to have a completely independent engine for the second rollers and the first rollers, in order to ability to spin second rollers much faster than the former, this to precipitate the vertical fall of the section of sheath cut on the object concerned. This approach is illustrated by document EP-A-0 109 105.

In this document, we use a presence of objects which, when an object arrives above the vertical conformator, triggers motor control drive of the first rollers and separate control second roller drive motors, for a advance of the sheath on the conformator, a cutting of this, and an ejection of the cut section on the object. In theory, this approach increases the rate of the laying machine, but this rate is actually limited the fact that the section of sheath cut is purely and simply ejected onto the object without any sound control movement of descent, and that the bringing of objects, by example by worms, is organized so independent, without any synchronization with the triggering of the descent of the cut section. In addition, for some advanced forms of objects, it is necessary with such a device to provide a sleeve diameter much larger than the maximum diameter of the object, which considerably limits control over the quality of retraction. In fact, when we arrive at the cadences high, we see that a certain number of sleeves are incorrectly positioned on the objects, a fortiori in the case of sleeves of significant height, and same as certain objects arriving downstream of the conveyor are not coated with a sleeve.

According to a second approach, always taking up the principle of first outer rollers ensuring the descent sheath, and second outer rollers arranged in downstream of the cutting device and ensuring the ejection of the section of sheath cut on an object, we planned a synchronization of the rotational drive of the first and second rollers. This is well illustrated in the document EP-A-0 000 851.

In this document, the ejector rollers arranged downstream of the cutting means are mechanically linked to first sheath ejector rollers, these the latter being rotated by an electric motor unique. In this case, we are assured of a perfect synchronization of the different movements, but we find limits in the possible rates, which are inherent in the fact that the same motor ensures the descent of the sheath, the cut thereof, and the fall of the section of sheath cut. Indeed, if we seek to increase the object scrolling speeds, especially if you want use sleeves with a diameter slightly larger at the maximum diameter of objects it becomes difficult to maintain the precision of the descent movement of sheath sections on objects, which objects can further present stability issues in the case high rates. Another disadvantage of this device lies in the constant speed imposed, which is inherent with a single engine, which can never change if you changes the cadence of the machine. So we can neither do vary the speed in normal operation, or take into account the upstream load of conveyed objects. In addition, note that the speed variation profile for a electric motor as used in the document EP-A-0 000 851, but also in the document previously commented on EP-A-0 109 105, is still in the form of a niche, with a high ramp for the rotation of the rollers, a horizontal step for the constant operating speed, and a steep ramp for stopping until the rollers are immobilized. This type of profile in niche, with two angular passages at the level of reaching and the cessation of constant speed, causes inevitably jerks that disrupt the smooth running of the laying process when we reach rates high. Such tremors prohibit the use of sleeves with one or more lines of micro-perforations to allow their opening. This problem is even more acute if one seeks to obtain sections cut very tall, because more power is required to the drive motor, and then we further increase the shaking.

The object of the invention is to improve a laying machine of the type which is described in document EP-A-0 000 851, keeping the principle of synchronization between the advance of the sheath on the former and ejection of the sheath section cut on the object concerned, by arranging the control and motorization means of so as not to meet the aforementioned drawbacks so much in terms of the precision of the transfer of the sections of sheath cut on objects, only at the level of constraints for the speeds used, which naturally opens the track at extremely high rates even in case of long sleeve lengths.

This problem is solved in accordance with the invention, thanks to a sleeve fitting device on moving objects, said sleeves being cut to from a continuous sheath passing over a conformator opening which is kept floating by cooperation between the first outer rollers and counter-rollers parallel axes carried by said shaper, said first rollers ensuring the advance of the sheath the along the conformator to a cutting means, seconds outer rollers being provided downstream of the cutting means to eject the cut sheath section on an object brought opposite the conformator by a conveying means not no objects, said first and second rollers being rotated by associated electric motors whose control is performed synchronously by a common electronic programmer arranged to determine a continuous speed variation profile for said speeds motors to control the transfer of each section of sheath on the corresponding object, and said programmer including at least one electronic control card which cooperates with an adjacent encoder mounted at the end of a shaft rotated by a central geared motor group.

Thus, the organization of the rotating order first and second rollers from a common encoder and at least one electronic axis control card allows perfect synchronization for first and second rollers, with very precise transfer of each section of sheath to the object corresponding.

Preferably, the continuous variation profiles speeds of electric motors for driving first and second rollers have a bell shape. This bell shape, which can approach a profile sinusoidal, is very far from the niche profile encountered in the earlier machines previously described. In effect, the absence of angular points on the profiles in bell removes the presence of tremors, even when the rates become very high. In addition, this remains true if you want to vary the speeds during normal walking, as long as you stay on bell-shaped profiles.

Preferably then, the profile associated with second rollers overhang the profile associated with the first rollers in the central area of the continuous profiles speed variation. This allows a first sheath section transfer phase with speed slowly increasing for a precise delivery of the stretch of sheath on the introduction part of the object concerned, then catching up with a very fast ejection of the sheath section, and finally an end of transfer very slowed down to have a very precise stop of the threaded sleeve on the object in the desired final position of said muff.

It is also advantageous to provide that the common electronic programmer has a series in memory couples of profiles in the shape of bells which are preprogrammed. This makes it possible to have a large number of pairs of bell-shaped profiles preprogrammed in depending on operating conditions, especially depending on the desired sleeve lengths or types of heat shrinkable plastic used, and also object feed speeds.

In accordance with an advantageous embodiment, the sleeve fitting device comprises a pair of first rollers driven by a common electric motor, and a pair of second rollers each driven by a associated electric motor, one of which is a slave to the other.

We can also provide that the installation device further includes third rollers arranged immediately downstream of the cutting means, said third rollers being mechanically coupled to the first rollers for rotate at a speed slightly higher than the speed of said first rollers. These third rollers are interesting to organize an aid for the separation of section cut from the rest of the sheath located upstream of the cutting means. It will then advantageously be provided that the device comprises a pair of third rollers, the axes are distant from the axes of the pair of second rollers a distance corresponding substantially to the length of the section of sheath cut.

Regarding the command associated with the means conveying objects step by step, we can resume classic designs based on mechanical drive direct from the central gearmotor, or more interestingly, use the principle of a control obtained by the rotary encoder which is provided in the laying device according to the invention. In this case, the aforementioned common programmer will also include a card control electronics associated with the conveyor means not step by step for the purpose of controlling the latter by the rotary encoder.

• la figure 1 illustre un dispositif de pose de manchons conforme à l'invention, avec une représentation symbolique des différents moyens d'entraínement en rotation des galets coopérant avec la gaine passant sur le conformateur, ici vertical, et avec le tronçon de gaine coupé ;
• la figure 2 est un diagramme illustrant deux profils en forme de cloches représentant les variations de la vitesse en rotation des galets d'avance de gaine et des galets éjecteurs, en fonction de l'angle de rotation de l'arbre portant le codeur angulaire.

Other characteristics and advantages of the invention will appear more clearly in the light of the description which follows and of the appended drawings, relating to a particular embodiment, with reference to the figures in which:

• Figure 1 illustrates a sleeve fitting device according to the invention, with a symbolic representation of the different means for driving the rollers in rotation cooperating with the sheath passing over the former, here vertical, and with the sheath section cut;
• FIG. 2 is a diagram illustrating two bell-shaped profiles representing the variations in the speed of rotation of the sheath advance rollers and the ejector rollers, as a function of the angle of rotation of the shaft carrying the angular encoder.

In Figure 1, there is a laying machine denoted P allowing to put sleeves on objects in scrolling, according to the invention.

Objects 10, represented in the form of bottles, run here on a conveyor belt 11 in a direction denoted 100, said conveyor belt being driven in step-by-step scrolling from a box 12.

In addition, a flat plastic sheath heat shrinkable 13 is supplied from a coil 14 rotatably mounted on a chassis part 16, said part sheath passing over rollers 17 and 18 to reach above a sheath opening shaper 20.

Conventionally, the opening shaper sheath 20, which is vertical here, has a part central 21, surmounted by a flat part 22, so as to gradually open the continuous sheath 13 arriving on said conformator. The sheath opening conformator 20 further comprises a downstream portion 23 connected to the central portion 21 by a ligament 24, a cutting means 27 with a movable knife 28 intervening at this level ligament to cut the sheath according to an instruction from command given. The conformator 20 is of the floating type, that is, it is maintained by cooperation between first outer rollers 30, 31 and pairs of counter rollers 25, 26 of parallel axes carried by said shaper. This would remain true if the conformer was horizontal, or even oblique, according to a variant not shown here.

The sheath continues 13, which passes over the part flattened 22 of the shaper 20, thus gradually opens on part 21 of said shaper, and passes between the roller 30 and the counter-rollers 25, and between the roller 31 and the counter-rollers 26 respectively, the said rollers 30, 31 thus ensuring both a floating support function of the conformator and, by their motorization, a function in advance, the sheath continues along said conformator.

Second outer rollers 32, 33 are provided downstream of the cutting means 28 for ejecting the section of cut sheath noted 15 on an object 10 brought opposite, that is to say here plumb, of the conformator, by means of step-by-step conveying of objects 11, 12.

Also illustrated in Figure 1 a motor central asynchronous type 40, which is used here both for the actuation of the cutting means 27 and for the drive of the means for conveying the objects 11, 12.

There is shown a motor output shaft 60 40, which, through a gear 61, drives a tree 62, which in turn, by a gear 63, operates the cutting means 27. The shaft 60 also carries a gear 64 which drives a shaft 65 connected to the drive box 12 of the conveying means. It goes without saying that the means conveyor shown here is only a representation given as an example, it being understood that provide equivalent mechanical drive systems objects, such as a pair of attached worms between which are placed the gradually conveyed objects. We will also see later that it is possible otherwise organize the control of the conveyor means not in step 11, 12 without using the mechanical transmission which has just been mentioned.

Asynchronous motor 40 is fitted with a reduction gear 45, which has an output shaft 46, the position of which angular is represented by the angle Θ, and at the end of which there is an encoder 47. This encoder includes an engraved disc with a large number of points, for example 20,000 points, representative of the angular position Θ of the tree 46. In accordance with a characteristic of the invention, it is this rotary encoder 47 which will make it possible to organize synchronized control of the various means of motorization serving to drive the rollers 30 in rotation, Sheath advance 31 on the former, and the rollers 32, 33 for ejecting the cut sheath sections 15 on the scrolling objects 10.

An electric motor is schematically represented 41 used to drive the pair of rollers 30, 31 sheath advance, and a motor 42 used to drive the pair of rollers 32, 33 for ejecting the cut sections. In the species, the pair of first rollers 30, 31 is driven by a common electric motor 41, while the rollers of the pair of second rollers 32, 33 are each driven by an associated electric motor 42, 43 one of which (here the motor 43) is a slave to the other (here motor 42). The master-slave connection is shown here by the line in dashed line 70. This master-slave connection, which is classic in the field of electric motors, is such that the roller 32 driven by the motor 43 rotates always at exactly the same speed as the roller 33 driven by the motor 42.

The first rollers 30, 31 in advance of the sheath and the second rollers 32, 33 for ejecting the cut section 15 are then rotated by electric motors associates 41, 42, 43 respectively whose command is performed synchronously by an electronic programmer common noted 50 which is arranged to determine a continuous speed variation profile for said speeds engines, in order to control the transfer of each section of sheath 15 on the corresponding object 10. We can use a multi-track electronic programmer, including at minus an electronic control card shown diagrammatically at 55, unique here, which specialists in the field call commonly called "axis control card". From this card control electronics 55, here unique, start two control lines marked 51 and 52, directed respectively to the input controls of the drive motors 41 rollers 30, 31, and 42 for driving the rollers 32.33. Thus, the control of the electric motors 41 and 42 is obtained with perfect synchronism resulting from the encoder turning 47 common which testifies, with precision extremely high inherent in the number of points of it, the single parameter represented by the angle of rotation Θ of the shaft 46 carrying said encoder. Like the coder turn 47 is mounted at the output of the gearmotor group central 40, 45, and that the motor 40 drives directly, here by mechanical means, the conveyor step by step of objects 11, 12, we are assured of synchronization perfect scrolling of objects with the organization of rotating regime of the rollers 30, 31 and 32, 33. The conditions are then ideal to pave the way for very high operating rates, while using sleeves whose diameter is barely greater than maximum diameter of the objects concerned.

Third pebbles are also provided here, arranged immediately downstream of the cutting means 27 intended to constitute aid for the separation of the section of sheath cut 15 relative to the portion of continuous sheath located upstream of the cutting means. In the present case, a distinction is made thus a pair of third rollers 34, 35 arranged immediately downstream of the cutting means 27, said third rollers being mechanically coupled to the first rollers 30, 31, for example by means of a belt 36, for rotate at a speed slightly higher than the speed of said first rollers. In practice, this speed will be about 1% faster than the speed of rotation of rollers 30, 31, this difference being automatically respected by the mechanical transmission 36. In this case, it is advantageous to provide that the pair of third rollers 34, 35 has axes that are distant from the pair of seconds rollers 32, 33 by a distance corresponding substantially to the length of the cut sheath section 15, so that the sheath section 15 either at the start of the cutting line at contact with the two pairs of rollers 32, 33 and 34, 35.

As mentioned above, the common electronic programmer 50 is arranged to determine a continuous profile of speed variation for the motors 41 on the one hand and 42, 43 on the other hand, in order to control the transfer of each section sheath 15 on the corresponding object 10. These continuous profiles are shown in FIG. 2, illustrating the variations in the speed denoted v as a function of the angle Θ of rotation of the shaft 46. A first profile P1 is thus distinguished corresponding to the motor 41 and a second profile P2 corresponding to the motors 42 and 43. As can be seen in FIG. 2, the profiles P1 and P2 each have a bell shape, here corresponding substantially to a portion of a sinusoid. It is important to note that at the central zone of the continuous speed variation profiles P1, P2, the profile P2 associated with the second rollers 32, 33, overhangs the profile P1 associated with the first rollers 30, 31. Each profile in bell shape ensures a speed increase and a decrease in speed quite progressive, without the presence of angular points as was the case for the slot profiles of previous laying machines. This continuous and continuously variable profile guarantees an absence of shaking, whatever the rate requested from the installation device. This absence of shaking allows, if desired, the use of sleeves having one or more lines of micro-perforations, even very sensitive, intended to facilitate their opening. The representation given here for the profile P2, with its central part which overhangs that of the profile P1, makes it possible to make it clear that the transfer of the cut sheath section 15 comprises a first phase of slow descent corresponding to the start of the separation of the section of sheath relative to the continuous sheath, then a rapid descent of the sheath section on the object, with a catch-up of the delay taken during the first phase of slow descent, and finally a slow terminal descent of the sheath section so that the position end of this section on the object is checked in a perfectly precise way.

These pairs of profiles P1, P2, which correspond in reality to a simulation of cam profiles, allow thus achieve a perfectly synchronized command electric motors rotating the rollers 30, 31 on the one hand and the rollers 32, 33 on the other hand. For the first time, the ejector rollers 32, 33 have a speed which, while being synchronized to that of sheath rollers 30, 31 in advance, is fully driven to have a perfectly controlled downward movement from start to finish for the cut sheath section 15. Good of course, we will profit, as is classic in electronic axis control systems, return information from motors 41, 42, 43 to the programmer 50 (in the case of electric motors with integrated encoder, this information then comes from these coders), which is shown here by arrows provided in the upper part said programmer. The electronic control card 55 sends at any time, and for each angular value of Θ corresponding to the angle of rotation of the bearing shaft 46 the encoder 47, control pulses to the motors 41 and 42 which correspond to the precise obtaining of the profiles of cams P1, P2 imposed. Controlling the control of motors 41, 42 allows each time to adapt the control of these engines in such a way that the drive remains exactly synchronized with the profiles in the form of desired bells.

It may be advantageous to provide that the common electronic programmer has in memory a series of pairs of profiles P1, P2 in the form of bells which are preprogrammed. The central programmer then controls engine control so that the actual conditions are wedged on these profiles in bells. This will allow to obtain a versatile use of the P cut, able to take into account different lengths usable sleeves, and also other conditions such as the thickness and / or the material of the sheath of heat-shrinkable plastic, and also object feed speeds.

As will be understood, it is now possible to vary the speed while walking normal, at any time, by simply working on the control of the central gearmotor group 40, 45. In indeed, any change in the rotation of the shaft 46 causes a change in the angular position of the encoder 47, and as a result of the control orders in the form of pulses sent by lines 51, 52 to motors 41 and 42. Thanks to the synchronization also planned for driving the conveying device step by step 11, 12, this change in speeds during normal operation is automatically reflected for the frame rate objects 10.

To perfect this general synchronization, we may provide that the common electronic programmer 50 also includes an associated control card by means of step-by-step conveying of objects with a view to controlling this last by the rotary encoder 47. In the present case, we have represented a card 55 with triple control of axes, with a third command line 54 shown in phantom starting from this electronic control card, and arriving on an electric motor 44 ensuring the drive conveying means step by step 11, 12 (we will note also feedback from the electric motor 44 to programmer 50, completing returns from motors 41, 42, 43). As the case may be, if only an electronic control card with double output of axis control, it will suffice to provide an additional card used only for controlling the electric motor 44 associated with the drive of the conveying means not to not 11, 12. These are only variations within reach specialists who are familiar with the use of electronic programmers for drive controls axes. This evolution of the installation device is naturally extremely interesting, to the extent where it achieves a generalized synchronization and very flexible for all electric drive motors, with absolute synchronization between the advance of the sheath, ejecting the cut sheath section, and scrolling objects next to the conformator. In this case single mechanical transmission from the central engine 40 is limited to the drive of the cutting means 27. By next, we can naturally use for the engine 40 a much smaller asynchronous motor than in the case where he must directly ensure the mechanical control of the means conveying step by step.

Synchronization of engine controls and control of the transfer of cut sheath sections thus make it possible to obtain a very high precision of positioning of the sleeves on the objects, even with high rates and with sleeve diameters at barely greater (for example 0.5 to 1 mm) than the diameter maximum of objects, which allows excellent control the quality of the retraction. The trials conducted by the plaintiff have thus found that obtained under these conditions an accuracy of the order of two tenths of a millimeter, and that for sleeves of long lengths (for example of the order of 250 mm), we could easily reach rates of 250 shots per minute.

This absolute synchronization therefore makes it possible to envisage duct designs that are extremely close to the dimensioning in section of the objects concerned. In fact, sleeves whose cross section can be used interior is extremely close to that of objects, without risk of improper positioning of these sleeves, thanks to the controlled transfer of these, while the laying machines must have had a set of safety, with significantly wider sheath sections in section as the section of objects. This is important particularly sensitive when using the device to install heat-shrink sleeves: if the dimensioning in section of the duct sections is close to the dimensioning in section of the objects to be coated, the retraction call is weak, and a very high control allowing total control of the retraction. On the contrary, in the laying machines security game, requiring the provision of sheath sections much wider than objects, in practice made it impossible to control quality of the retraction.

Thus, the installation device which has just been described allows both optimal control of positioning of the sleeve on the object thanks to the transfer of said sleeve which is piloted from start to finish, which was not the case with the ejector rollers of the laying machines traditional which only ejected the sections cut to a top given by a cell. We also get a follow-up of this transfer of cut sections with the moving objects while keeping synchronization sleeve side and object side for all speeds planned diet including naturally large speeds.

The invention is not limited to the embodiment which has just been described, but on the contrary includes any variant using, with equivalent means, the essential characteristics stated above.

Claims (8)

1. Apparatus for placing sleeves onto conveyed articles, said sleeves being cut from a continuous sheath (13) passing over a sheath opening shaper (20) which is held floating by co-operation between first outside wheels (30, 31) and parallel-axis backing wheels (25, 26) carried by said shaper, said first wheels causing the sheath to advance along the shaper (20) up to cutting means (27), second outside wheels (32, 33) being provided downstream from the cutting means (27) to eject the cut-off sheath segment (15) onto the article (10) fed into register with the shaper by stepper conveyor means (11, 12) of the articles, the apparatus being characterized in that the first wheels (30, 31) and the second wheels (32, 33) are rotated by associated electric motors (41; 42, 43) controlled synchronously by a common electronic programmer (50) arranged to determine a continuous profile (P1, P2) for speed variation of said motors so as to control the transfer of each sheath segment (15) onto the corresponding article (10), said programmer including at least one electronic control card (55) which cooperates with an adjacent encoder (47) mounted at the end of a shaft (46) rotated by a central motor and gearbox unit (40, 45).
2. Sleeve-placing apparatus according to claim 1, characterized in that the continuous profiles (P1, P2) for speed variation of the electric drive motors (41; 42, 43)- of the first and second wheels (30, 31; 32, 33) are bell-shaped.
3. Sleeve-placing apparatus according to claim 2, characterized in that the central portions of the continuous speed variation profiles (P1, P2) are such that the profile (P2) associated with the second wheels (32, 33) is taller than the profile (P1) associated with the first wheels (30, 31).
4. Sleeve-placing apparatus according to claim 2 or claim 3, characterized in that the common electronic programmer (50) has in memory a series of pairs of bell-shaped profiles (P1, P2) which are preprogrammed.
5. Sleeve-placing apparatus according to any one of claims 1 to 4, characterized in that it has a pair of first wheels (30, 31) driven by a common electric motor (41), and a pair of second wheels (32, 33) each driven by a respective electric motor (42, 43) one of which (43) is slaved to the other (42).
6. Sleeve-placing apparatus according to any one of claims 1 to 5, characterized in that it further includes third wheels (34, 35) disposed immediately downstream from the cutting means (27), said third wheels being mechanically coupled to the first wheels (30, 31) to rotate at a slightly higher speed than the speed of said first wheels.
7. Sleeve-placing apparatus according to claims 5 and 6, characterized in that it includes a third pair of wheels (34, 35) whose axes are offset from the axes of the second pair of wheels (32, 33) by a distance which corresponds substantially to the length of a cut-off sheath segment (15).
8. Sleeve-placing apparatus according to any one of claims 1 to 7, characterized in that the common programmer (50) also includes an electronic control card (55) associated with the stepper conveyor means (11, 12) for conveying the articles, in order to control said means from the rotary encoder (47).

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