EP2154072B1 - Device for setting sleeves on objects moving past - Google Patents

Abstract

The machine (M) has a common electronic programmer (50) with a virtual shaft arranged for determining bell-shaped continuous profiles of speed variation for electric motors (41-43). The profiles comprise a common terminal segment whose length is chosen corresponding to identical speed of the motors for advancing a continuous flat sheath (13) over a tangency point of two ejecting rollers (32, 33) such that the sheath is pinched by the rollers before immobilizing the sheath for cutting and ejecting the sheath. The sheath is made of thermoplastic material.

Description

The present invention relates to the laying of sleeves, in particular the installation of heat shrink sleeves, on moving objects, the coated objects of their sleeve then passing at a retraction furnace.

BACKGROUND OF THE INVENTION

For the installation of heat-shrink sleeves on moving objects, a technique is conventionally used in which the sleeves are cut from a continuous sheath passing over a sheath-opening shaper, which is kept floating by cooperation between outer rollers. and counter-rollers of parallel axes carried by the shaper, which outer rollers ensure the advance of the sheath along the shaper, generally vertical, to and beyond a cutting means. Other rollers are generally provided downstream of the cutting means for ejecting the section of sheath cut on the object coming directly above the shaper.

Thus, in most of the techniques used, there are first outer rollers intended to ensure the advance of the sheath on the shaper, and second outer rollers for ejecting the section of sheath cut on the object concerned. All these outer rollers are of course motorized, and their motorization has given rise to different types of arrangements.

It has thus been proposed to have a completely independent motorization for the second rollers and the first rollers, in order to be able to turn the second rollers much faster than the first, in order to precipitate the vertical fall of the section of sheath cut on the object concerned. This approach is illustrated in the document EP-A-0 109 105 . According to another approach, a synchronization of the rotational drive of the first and second rollers is provided, as illustrated in the document EP-A-0 000 851 .

However, it was found that the aforementioned techniques imposed limits in terms of timing, because, when arriving at high speeds, it was found that sleeves were often poorly positioned on objects, especially if it s 'was of large height sleeves.

An important step has been taken more recently with a technique implementing a control of the relevant electric motors performed in synchronism by a common electronic programmer arranged to determine a continuous profile of variation of the speeds, in order to control the ejection of each section of sheath. , said programmer including at least one control card which cooperates with an adjacent encoder mounted at the end of a shaft driven in rotation by a central geared motor unit. This is illustrated in the document WO-A-99/59871 of the plaintiff.

The document WO-A-99/59871 aforesaid and describes a device for laying sleeves on moving objects, said sleeves being cut from a continuous sheath passing over a shaper opening shaper, which shaper is kept floating between first outer rollers and counter rollers of parallel axes carried by said shaper, said first rollers ensuring the advance of the sheath along the shaper to and beyond a cutting means, the second outer rollers being provided downstream of the cutting means for ejecting the section of sheath cut on an object coming directly above the shaper, said first and second rollers being rotated by associated electric motors whose control is carried out in synchronism by a common electronic programmer with a virtual shaft, said programmer electronics being arranged to determine a continuous profile of bell-shaped speed variation for the motors associated electrical equipment, in accordance with preamble of claim 1.

With the latter technique, the synchronization has allowed to consider higher rates than previously, and with a sleeve diameter barely greater than the maximum diameter of the objects.

There is, however, a growing demand for increasingly higher clock speeds, typically ranging from 300 to 600 strokes per minute.

It was then preferred to use more sophisticated machines, by abandoning the system of stepwise advancement of the objects, as well as the encoder system mounted at the end of a shaft driven in rotation by a central geared motor unit (as described in FIG. the document WO-A-99/59871 above), and use a common electronic virtual shaft programmer to control all electric motors.

Parallel to this search for very high rates, there is also a tendency to use sheaths made from a heat shrinkable film of increasingly weaker thickness. As an indication, the conventional techniques used heat-shrinkable films whose thickness was of the order of 50 microns, whereas now it is sought to use heat-shrinkable plastic films of smaller thickness, that is to say that can down to 25 μm, and also of lower density.

The aforementioned double requirement thus considerably complicates the arrangement of the sleeves laying devices, and one can note a type of technical problem that arises more and more acute, and which concerns the positioning of the sheath on the shaper at the time of immobilization thereof for the cutting pass and ejection.

Indeed, the slightest variation in the position of the downstream portion of the sheath on the shaper, which will giving rise to the section to be ejected after the cutting pass, has the effect of giving very variable heights for cut sections of sheath (the height of the section being measured in the direction of the generatrices of said section).

In the document WO-A-99/59871 mentioned above, it has been proposed to arrange the control of the electric motors associated with the first sheath feed rollers and the second ejection rolls of the cut sections in such a way that the continuous profiles of speed variations for said motors have a shape bell, and not angular niche as was the case previously. However, it was found that by operating such a device at very high rates, the aforementioned bells curves raised problems of accuracy at the end of the advancement / ejection cycle, and this even by adopting a common electronic programmer. virtual tree.

This inaccuracy is also found when the laying device is stopped, before a new period of operation, so that the position of the sheath is de facto imprecise to resume operation.

The direct consequence of this is that the axial position of the sheath on the shaper is in fact never defined with complete precision. In practice, the free edge of the sheath is immobilized slightly upstream of the second ejection rollers, the next thrust of the sheath then bringing this free edge into contact with the ejection rollers for the ejection process. The fact remains that the height of the sections is not perfectly constant, and that it is not possible to completely eliminate the risk of slipping of the sheath on the shaper when it is immobilized for the pass cutting and ejecting.

OBJECT OF THE INVENTION

The object of the invention is to design a device for fitting sleeves on moving objects that do not have the aforementioned drawbacks and limitations with regard to the technical problem set out above, in connection with the positioning of the sheath on the shaper at the moment. immobilization thereof for the cutting pass and ejection, and also when shutting down said device.

The object of the invention is also to propose a sleeve laying device arranged to allow very high clocking, which can reach 600 shots per minute, even using continuous sheaths made from thin films, for example able to down to 25 microns, and low density, especially of density less than 1.

GENERAL DEFINITION OF THE INVENTION

• les seconds galets extérieurs éjectent le tronçon de gaine coupé sur un objet par suite du passage dudit objet devant une cellule, et
• les profils continus en forme de cloches présentent un tronçon terminal commun où les profils sont confondus, ce qui correspond à une vitesse identique des moteurs électriques associés, la longueur de ce tronçon terminal commun étant choisie pour que la gaine soit avancée au-delà du point de tangence des seconds galets, de façon que ladite gaine soit pincée par lesdits seconds galets avant d'être immobilisée pour la passe de coupe et d'éjection,

conformément à la partie caractérisante de la revendication 1.The aforementioned problem is solved according to the invention by means of a sleeves installation device of the aforementioned type, in which:

• the second outer rollers eject the section of sheath cut on an object as a result of the passage of said object in front of a cell, and
• the continuous profiles in the form of bells have a common terminal section where the profiles are merged, which corresponds to an identical speed of the associated electric motors, the length of this common terminal section being chosen so that the sheath is advanced beyond the point of tangency of the second rollers, so that said sheath is gripped by said second rollers before being immobilized for the cut and ejection pass,

according to the characterizing part of claim 1.

Thus, the aforementioned characteristics make it possible to guarantee that the free end of the sheath is always correctly gripped by the second ejection rolls of the cut sections before being immobilized for the cutting and ejection pass. Such an advance beyond the point of tangency indeed ensures a stop of the sheath in positive engagement, which de facto eliminates any risk of sliding of the sheath on the shaper, and contributes thus obtaining a perfectly regular cutting edge. It is indeed easy to understand that the process of ejection of the section of sheath cut can start instantly, without the least dead time, thanks to the aforementioned positive grip.

Preferably, the virtual electronic virtual shaft programmer includes at least one control electronic card associated with the electric motors for driving the rollers, which is arranged in such a way that the length of the common terminal section, which corresponds to the variations of the speeds for the electric motors according to the angular position of their respective virtual shaft, either directly representative of a predetermined distance between the point of tangency and the free edge of the sheath at the time of immobilization of said sheath for the cutting pass and d 'ejection. Advantageously then, this predetermined distance is also established when the laying device is stopped, and remains frozen during the entire period of non-operation of said device.

It may for example be provided that the aforementioned distance between the point of tangency and the free edge of the sheath is essentially between 0.5 and 3 mm, preferably being close to 1 mm.

It can advantageously be provided that the second rollers are mounted on a support whose position is adjustable in the direction of the axis of the shaper, so as to allow adjustment of the distance between the point of tangency and the free edge of the sheath. moment of immobilization of said sheath for the cutting and ejection pass.

According to a particular embodiment, the shaper has a smooth-walled downstream end, and the sheath is then pinched, at the time of immobilization of said sheath for the cutting and ejection pass, between the second rollers and said smooth wall.

Alternatively, it may be provided that the shaper is equipped, at its downstream end, against-rollers, and the sheath is then, at the time of immobilization of said sheath for the cutting pass and ejection pinch between the second rollers and said associated counter rollers.

Advantageously then, the second rollers and the associated counter rollers have axes which are contained in a common plane perpendicular to the axis of the shaper.

Other features and advantages of the invention will appear more clearly in the light of the description which follows and the accompanying drawings relating to a particular embodiment.

BRIEF DESCRIPTION OF THE DRAWINGS

• la figure 1 illustre un dispositif de pose de manchons conforme à l'invention, avec une représentation symbolique des différents moyens d'entraînement en rotation des galets coopérant avec la gaine passant sur le conformateur, ici d'axe vertical, et avec le tronçon de gaine coupé ;
• la figure 2 est un diagramme illustrant les profils des variations de la vitesse en rotation des galets d'avance de gaine et des galets éjecteurs, en fonction de la position angulaire des arbres virtuels respectifs des moteurs électriques associés, ces profils étant en forme de cloche avec un tronçon terminal commun où les profils sont confondus, conformément à une caractéristique essentielle de l'invention ;
• la figure 3 est une vue partielle en élévation illustrant la situation au moment de l'immobilisation de la gaine, juste après la passe de coupe et avant l'éjection du tronçon de gaine coupé, en l'espèce avec un dispositif de pose de manchons de type traditionnel, la figure montrant en particulier la position dudit tronçon de gaine coupé à éjecter par rapport aux galets éjecteurs ;

• la figure 4 est une vue analogue à celle de la figure 3, mais avec un dispositif de pose de manchons mettant en oeuvre l'invention, illustrant la même situation avec la nouvelle position du tronçon de gaine coupé à éjecter, dont le bord aval est maintenant pincé par les galets éjecteurs, cette position figée étant également celle qui prévaut lors de la mise à l'arrêt du dispositif de pose ; et
• la figure 5 est une vue partielle illustrant, à plus grande échelle, le phénomène de pincement précité.

Reference will be made to the figures of the accompanying drawings, in which:

• the figure 1 illustrates a sleeves installation device according to the invention, with a symbolic representation of the various means for rotating the rollers cooperating with the sheath passing over the shaper, here vertical axis, and with the section of sheath cut;
• the figure 2 is a diagram illustrating the profiles of the variations in the rotational speed of the sheath feed rollers and ejector rollers, as a function of the angular position of the respective virtual shafts of the associated electric motors, these profiles being bell-shaped with a section common terminal where the profiles are combined, according to an essential characteristic of the invention;
• the figure 3 is a partial view in elevation illustrating the situation at the time of the immobilization of the sheath, just after the cutting pass and before the ejection of the section of sheath cut, in this case with a device for laying sleeves of traditional type , the figure showing in particular the position of said section of sheath cut to eject relative to the ejector rollers;

• the figure 4 is a view similar to that of the figure 3 , but with a sleeves installation device embodying the invention, illustrating the same situation with the new position of the cut sheath section to be ejected, whose downstream edge is now gripped by the ejector rollers, this fixed position being also that prevails when shutting down the laying device; and
• the figure 5 is a partial view illustrating, on a larger scale, the pinching phenomenon mentioned above.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

On the figure 1 , there is a laying machine denoted M, for laying sleeves on moving objects, arranged in accordance with the invention.

The laying machine M has a number of points in common with the laying machine described in the document WO-A-99/59871 above mentioned by the plaintiff. These common elements will therefore be briefly described, but reference may be made to the above document for further details.

Objects 10, represented here in the form of flasks, run on a conveyor belt 11 in a direction denoted 100, said conveyor belt being driven in motion by associated means not shown here.

A flat sheath of heat-shrinkable plastics material 13 is fed from a spool 14 rotatably mounted on a frame portion 16, said sheath passing over return rollers 17 and 18 to arrive over an opening shaper sheath 20. The sheath opening shaper 20, which is here of vertical axis X, comprises an upstream central portion 21 surmounted a flat portion 22, so as to gradually open the continuous sheath 13 arriving on said shaper. The sheath opening shaper 20 further comprises a downstream portion 23, which extends the upstream central portion 21, the separation being made at a groove 24.

A cutting means 27 with at least one movable blade 28 is carried by a rotating support 29 arranged at the groove 24 to cut the sheath according to a given control instruction, the cut being circularly in a plane P perpendicular to the X axis of the shaper, that is to say in this case essentially horizontal.

The shaper 20 is of floating type, being held by cooperation between first outer rollers 30, 31 and counter rollers 25, 26 of parallel axes carried by said shaper.

The continuous sheath 13 thus opens progressively on the upstream portion 21 of the shaper 20, and passes between the roller 30 and the counter rollers 25, and between the roller 31 and the counter rollers 26, respectively, the rollers 30, 31 thus ensuring both a floating support function of the shaper 20 and, by their motorization, a function of advance of the continuous sheath 13 along said shaper.

Second outer rollers 32, 33 are provided downstream of the cutting means 27 for ejecting the cut sheath section, noted 15, on an object 10 coming directly above the shaper 20, as a result of the passage of said object in front of a fixed cell. 80.

There is shown schematically an electric motor 41 for driving the pair of rollers 30, 31 of sheath feed, and two electric motors 42, 43 for driving the rollers 32, 33 for ejection of the clipped section of sheath.

The cutting means 27 is carried by a rotating support 29 which here consists of two rings superimposed 55, 57 driven in rotation, and whose rotation speed difference ensures, by means of a cam system, the alternating pivoting of the cutting blade or blades 28 between a retracted position and a cutting position. The driving of these two superimposed rings 55, 57 is ensured, by means of belts 56, 58, by two electric motors 48, 49.

The aforementioned electric motors 41, 42, 43, 48, 49 are connected by respective associated lines 51, 52, 53, 54, 54 'to a virtual electronic programmer 50 with a virtual shaft. The cell 80 which sees each scrolling object 10 is connected by a line 81 to the common electronic programmer 50, in particular to transmit the signal authorizing the control of the motors 42, 43 associated with the ejection of the section of sheath cut on the object 20 coming in line with the shaper 20. The general synchronization is ensured by the common electronic virtual shaft programmer 50 which includes at least one electronic control card 55 with multiple commands which is connected to the control lines 51, 52, 53 , 54, 54 'above.

The common electronic programmer 50 is in particular designed to determine a continuous variation profile of the speeds for the electric motors 41, 42, 43 associated with the rotational drive of the first rollers 30, 31 and the second rollers 32, 33. which are different from the profiles illustrated in the document WO-A-99/59871 above, are illustrated here on the figure 2 , which gives the variations of the speed v as a function of the angular position θ of the associated virtual trees.

As this is illustrated on the figure 2 the continuous profiles, denoted P1 (for the electric motor 41) and P2 (for the electric motors 42, 43), are bell-shaped. The advantages of such a bell-shaped profile have been detailed in the document WO-A-99/59871 aforementioned, advantages especially with regard to the profiles of previous variations in the form of rectilinear niche.

However, unlike the profiles illustrated in the aforementioned document, the continuous profiles P1, P2 here comprise a common terminal section where the profiles are merged, which corresponds to an identical speed of the associated electric motors. Thus, the two bell-shaped profiles P1, P2 meet at a point A and, from this point, the two profiles coincide to a point C of zero speed. This common terminal section AC passes through a point B corresponding to a slowing down of the speed v. The precise position of the point A is not known with certainty, but the length of the common terminal section is sufficient for the existence of such a section is guaranteed, with the resulting benefits.

The common section AC, which corresponds to an identical speed of the associated electric motors, thus has a specific length which is chosen so that the sheath 13 is advanced beyond the point of tangency Q (better visible on the figure 5 ) second rollers 32, 33, so that said sheath 13 is clamped by said second rollers before being immobilized for the cutting pass and ejection.

This additional advance is in practice essential, because it guarantees a stop of the sheath on the shaper in positive grip. As a result, when the sheath feed rollers 30, 31 and the ejector rollers 32, 33 are stopped for a short time for the cutting and ejecting pass, no slippage is to be feared for the sheath 13 on the shaper 20, and it is ensured a perfect start and instant ejection by the ejector rollers cut section of sheath 15.

This also applies when shutting down the laying device, and during the entire period of no operation of said device, wherein the pinched sheath remains positioned very precisely. This frozen position allows immediate recovery of operation without loss of accuracy.

The figure 3 illustrates a situation as it was encountered with a traditional technique, for example that described in the document WO-A-99/59871 supra.

This figure shows the plane P corresponding to the plane of section which is perpendicular to the X axis of the shaper 20, the sheath feed rollers 30, 31, and the ejector rollers 32, 33 which are carried by associated supports 37, 38. The cut sheath section 15, which is here shown hatched for convenience, is then in a position such that its downstream free end edge 36 is generally above the point of tangency of the ejector rollers 32, 33. We then find the situation of inaccuracy which was found in the introductory part of the description.

The figure 4 is a figure similar to that of the figure 3 , with the same references, illustrating the situation at an identical moment but with a laying device according to the invention.

The larger-scale detail of the figure 5 allows better understanding the additional advance printed to the sheath 13 to ensure effective clamping of said sheath by the ejector rollers 32, 33.

The figure 5 shows the downstream end zone of the sheath 13, with its nip by the ejector roller 33, the nip being such that the free end edge 36 of said sheath has been advanced beyond the point Q of tangency, of a predetermined distance noted d. One finds naturally the same situation at the level of the other ejector roller 32.

As will be understood, the length of the section AC common above, which corresponds to the variations of the speeds for the electric motors 41, 42, 43 as a function of the angular position e of their respective virtual tree, is directly representative of the aforementioned predetermined distance d between the point of tangency Q and the edge free 36 of the sheath 13 at the time of immobilization of the sheath for the cut pass and ejection.

As an indication, the predetermined distance d between the point of tangency Q and the free edge 36 of the sheath 13 is essentially between 0.5 and 3 mm, preferably being close to 1 mm.

On the figure 4 it has moreover been illustrated by a double arrow 39 that the supports 37, 38 of the rollers 32, 33 are of adjustable position in the direction of the axis X of the shaper 20, which in this case is the vertical direction . This height adjustment thus makes it possible to adjust the distance d mentioned above, and to adapt to any change in height of the duct section in association with other objects in scrolling.

The shaper 20 may have a downstream end with a smooth wall, in which case the sheath 13 is then clamped between the second rollers 32, 33 and said smooth wall. However, especially in view of the very high rates mentioned above, it is preferable, as illustrated on the figure 4 to provide against-rollers 34, 35 facing the ejector rollers 32, 33. In this case, the sheath 13 is clamped between the second rollers 32, 33 and the associated counter rollers 34, 35 which are carried by the shaper 20.

Although this is not an absolute necessity, it is interesting to predict, as is best seen on the figure 5 , that the second rollers 32, 33 and the associated counter rollers 34, 35 have axes which are contained in a common plane R perpendicular to the axis X of the shaper 20.

If we finally come back to figure 2 it is found that the common terminal section AC of the two bell-shaped profiles P1 and P2, which passes through the point B, continues at a zero speed (point C) to a point D which corresponds to the recovery of the next cycle.

It has thus been possible to produce a device for fitting sleeves on scrolling objects which substantially improves the previous device of the document. WO-A-99/59871 , by improving the accuracy of the positioning of the sheath on the shaper.

The laying machine allows use at very high speeds, for example 600 rounds per minute, and with sheaths whose constituent film is thin, for example 25 microns, and low density, for example a density less than 1.

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

Claims (8)

1. A device for placing sleeves on traveling articles, said sleeves being cut from a continuous sheath (13) passing over a sheath-opening shaper (20), which shaper (20) is held floating between first outer wheels (30, 31) and backing wheels (25, 26) having parallel axes carried by said shaper, said first wheels (30, 31) serving to cause the sheath (13) to advance along the shaper (20) up to and beyond cutter means (27), second outer wheels (32, 33) being provided downstream from the cutter means (27) to eject each cut-off sheath segment (15) onto an article (10) located vertically below the shaper (20), said first and second wheels (30, 31; 32, 33) being driven in rotation by associated electric motors (41; 42, 43) that are controlled synchronously by a virtual-shaft common electronic programmer (50), said electronic programmer (50) being arranged to determine a continuous bell-shaped profile (P1, P2) for varying the speeds of the above-mentioned associated electric motors (41; 42, 43), the device being characterized in that :

   - said second outer wheels (32; 33) eject the cut-off segment of sheath (15) onto an article (10), as a result of said article moving past a cell (80);

   - said continuous bell-shaped profiles (P1, P2) having a common end segment (AC) in which the profiles coincide, thus corresponding to said associated electric motors having speeds that are identical, the length of said common end segment (AC) being selected so that the sheath (13) is advanced beyond the point (Q) of tangential contact with the second wheels (32, 33), in such a manner that said sheath (13) is pinched by said second wheels prior to being held stationary for the cutting and ejection pass.
2. A sleeve-placing device according to claim 1, characterized in that the virtual-shaft common electronic programmer (50) includes at least one controlling electronic card associated with the electric motors (41; 42, 43) for driving the wheels, which card is arranged in such a manner that the length of the common end segment (AC) that corresponds to the variations in the speeds of the electric motors (4; 42, 43) as a function of the angular positions (θ) of their respective virtual shafts, is directly representative of a predetermined distance (d) between the point (Q) of tangential contact and the free edge (36) of the sheath (13) at the time said sheath is being held stationary for the cutting and ejection pass.
3. A sleeve-placing device according to claim 2, characterized in that the predetermined distance (d) is also established when the sleeve-placing device is stopped, and remains frozen throughout the period said device is not in operation.
4. A sleeve-placing device according to claim 2 or claim 3, characterized in that the predetermined distance (d) between the point (Q) of tangential contact and the free edge (36) of the sheath (13) lies essentially in the range 0.5 mm to 3 mm, and is preferably close to 1 mm.
5. A sleeve-placing device according to any one of claims 1 to 4, characterized in that the second wheels (32, 33) are mounted on respective supports (37, 38) that are adjustable in position in the direction of the axis (X) of the shaper (20), so as to adjust the distance (d) between the point (Q) of tangential contact and the free edge (36) of the sheath (13) at the time said sheath is being held stationary for the cutting and ejection pass.
6. A sleeve-placing device according to any one of claims 1 to 5, characterized in that the shaper (20) has a smooth-walled downstream end, and the sheath (13) is then pinched, at the time said sheath is being held stationary for the cutting and ejection pass, between the second wheels (32, 33) and said smooth wall.
7. A sleeve-placing device according to any one of claims 1 to 5, characterized in that the shaper (20) is fitted at its downstream end with backing wheels (34, 35), and the sheath (13) is then pinched, at the time said sheath is being held stationary for the cutting and ejection pass, between the second wheels (32, 33) and the associated backing wheels (34, 35).
8. A sleeve-placing device according to claim 7, characterized in that the second wheels (32, 33) and the associated backing wheels (34, 35) have axes that slide in a common plane (R) perpendicular to the axis (X) of the shaper (20).

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