FR2751629A1 - Buffer drum for continued delivery of strip while supply reel is changed e.g. in labelling - Google Patents

Abstract

The buffer drum is positioned between the main supply reel delivering a continuous strip and the machine using the strip. The buffer drum comprises a rotating receiving drum (5) and a delivery drum (9). The receiving drum has an internal rotating collector (6) formed by an endless belt (7) shaped as a circular wall inside the collector. A gap in the wall allows strip to be wound onto a drum (8) to form a reserve. The fixed delivery drum is inside the receiving drum, and coaxial with it, and has an internal circular guide (11) formed by another endless belt, with a gap (113) similar to the outer guide to allow entry of strip.

Description

 The present invention relates to a buffer accumulator intended to be mounted in a processing line using a ribbon-shaped product supplied by a spool and feeding the processing machine without interruption during the changing of the spool.

 In certain industries such as that of packaging, products are used in the form of a strip, for example bands of sleeves intended for the covering and / labeling of products such as bottles, bottles, metal, plastic or cardboard boxes. The machine for laying these sleeves receives the products to be treated as well as the ribbon (in fact a tube) of sleeves. These sleeves are detected and sectioned on the machine and placed over the products to be heat-shrunk thereon.

 As the ribbon can only be supplied in spools which necessarily correspond to a limited length of ribbon, to place a new spool, the machine must be stopped during the time of the spool change. For this change, the start of the new reel is connected to the end of the ribbon starting from the reel which has just been emptied.

 Even carried out quickly, this operation requires a few minutes and, in addition to the intrinsic loss of time, it requires the stopping of the treatment machine and a new start-up with progressive acceleration to normal walking speed.

 In addition to the loss of time linked to the replacement of the coil, this discontinuous operation has the disadvantage of a break in the normal operation of the processing machine with its inevitable consequences, namely possible scrapping of parts treated during the restart phase.

 The present invention aims to remedy these drawbacks and proposes to create a buffer accumulator, simple and safe operation, compact, which can be easily integrated between the ribbon supply reel and the machine supplied with ribbon. .

To this end, the invention relates to an accumulator of the type defined above, characterized in that
A) a rotary receiving drum,
- fitted with a receiving unit, rotating relative to the drum formed by an endless band describing a circular path in C, by its outer strand and leaving an entry gap to form a winding reserve receiving the ribbon on its outer turn and unwinding it through its inner turn, passing through the interval,
- the endless belt being movable relative to the crew,
B) a stationary transmitting drum fitted with an emission equipment
fixed,
- formed of a moving endless band describing a C-shaped circular path. Thus by the outer strand with passage interval to form on the outer strand a winding reserve receiving the ribbon on its outer coil and unwinding it by its inner whorl passing through the interval.

C) the transmitter drum being placed coaxially inside
of the receiving drum,
D) drive and control means for driving
the receiving crew and / or the receiving bands and
resignation,
E) the path followed by the tape unwound from a reel passing over
the receiving drum to form the turns constituting
a reception reserve on the outside of the strip
of the receiving crew, the inner coil of this re
serve unwinding through the slot of the receiving crew
and passing over the transmitting drum to form on the strand
exterior of the transmitting crew, turns constituting
an emission reserve from which the inner coil is unwound
to be extracted through the crew slot
and supply the machine,
- the reception reserve being formed during the unwinding of the reel to constitute a reserve of time necessary for changing the reel,
- this reception reserve being transferred to the transmission reserve while the supply to the reception reserve is stopped during the reel change.

 This accumulator is of a simple construction and of very reduced volume, since it is made up in a way of two drums placed one inside the other, driven and controlled.

The assembly is very easily placed between the supply reel and the machine without cluttering the production line and even a return provided at the output of the accumulator makes it possible to place this machine next to the processing machine and not necessarily in the alignment of it.

 The buffer accumulator receives the ribbon and gradually builds up a reserve by unwinding the supply reel in a shorter time than the processing machine needs to consume the length of ribbon corresponding to a reel. This reduction in the ribbon recovery time thus makes it possible to create a reserve of time necessary for the removal of the old reel, the establishment of the loaded reel and the connection of the primer of the loaded reel to the end of the ribbon of the reel which has just been finished.

 The ribbon supplying the receiving drum is stopped during this whole time of reel replacement. Meanwhile, the reception crew unwinds the reserve of reception ribbon to supply the processing machine and at the same time build up a reserve of ribbon on the transmission crew of the transmitting drum. The sending drum then practically depletes its emission reserve, then the receiving drum recharges with tape from the new reel and the operations resume as described.

 This buffer accumulator respects the ribbon structure of the product thus accumulated without exerting traction which risks breaking, stretching, deforming or creasing it, since it is generally but not exclusively plastic material such as polyethylene .

 As the reception and emission reserves are alternately made and unmade and there is no problem of increasing the diameter of the reserve since at the end of the exhaustion of each reserve, the light pulls existing bring the last turns or interior turns back into contact with the endless band of the receiving crew and the transmitting crew.

According to other features of the invention
- the receiving and / or transmitting equipment comprises a guide surface in the form of a circle interrupted by a slot bordered by cylinders forming the circular path in C for the outer strand of the strip, the inner strand penetrating through the slit (at inside the guide surface to follow its inner contour
- the receiving and / or transmitting equipment includes a guide surface to support the inner strand of the ribbon
- the guide surfaces are provided with edges to form a path receiving the outer strand of the endless ribbons and the reserves.

The present invention will be described below in more detail using an embodiment shown schematically in the accompanying drawings in which
- Figure 1 shows the buffer accumulator
- Figures 2A, 2B show the receiving drum of the buffer accumulator in two operating states
- Figures 3A, 3B show the transmitter drum 10 in two operating states
According to FIG. 1, the invention relates to a buffer accumulator intended to be mounted between a supply coil 1 supplying a ribbon 2 and a machine 3 receiving the ribbon 2 continuously and at a constant speed.

 This accumulator 4 consists of a receiver drum 5 rotating around an axis O and a transmitter drum 10 housed inside the receiver drum 5, on the axis 0 but not rotatable.

 Very schematically, the receiving drum 5 receives the tape 2 unwound from the supply reel 1 to supply it to the sending drum 10 which delivers the tape 2 to the machine 3.

The ribbon 2 is first accumulated on the receiving drum 5 to empty the supply reel more quickly than the ribbon 2 is supplied by the transmitting drum 10 to the machine 3, thereby saving usable time for the change. coil 1, and do not interrupt or slow down the ribbon supply to machine 3.

To facilitate the description of the buffer accumulator, the assembly shown schematically in Figure 1 is shown separated into its two parts
- receiver drum 5 (Figure 2A)
- the transmitter drum 10 (FIG. 3A)
According to FIG. 2A, the receiving drum 5 comprises a receiving equipment 6 composed of an endless band 7 describing a path in the form of C. The outer strand 71 of this band 7 describes the exterior side of this path in the form of C and the inner strand 72 connects the two ends of the outer strand 71.

 In fact, the C-shaped path is materialized by a guide surface 73, circular, interrupted only by a slot 74 bordered by two cylinders 75, 76.

 The outer strand 71 of the endless belt 7 follows the guide surface 73; it enters through the slit 74 passing over the cylinder 75 to describe on the inside in the form of the strand 71, a path conforming as closely as possible, the outer strand 71 or its guide surface 73, so as to leave inside the inner strand 72, a free volume as large as possible for receiving the transmitter drum 10.

 Advantageously, the inner strand 72 is supported and slides on the circular guide surface 77.

 The slot 74 is very small and the outer strand 71 or its guide surface 73 form a practically closed circular path.

 Indeed, the outer strand 71 constitutes the support surface receiving the turns of ribbon 2.

 This winding of ribbon turns 2 constitutes a reserve 8: the outer turn begins with the part of ribbon 21 arriving on the reserve; the inner turn, directly located on the outer strand 71 of the ribbon 7 leaves the reserve 8 through the portion of ribbon 22 passing through the slot 74.

 To facilitate the interpretation of the figures and in particular of FIG. 2A, the reserve 8 is shown at a certain distance from the crew 6 and in particular from the outer strand 71; the latter is itself shown above and not in contact with the guide surface 73.

 In reality, the outer strand 71 is applied to the guide surface 73 and the reserve 8 is directly in contact with the outer strand 71.

 It should also be noted that the outer strand 71 never slides relative to the inner coil of the reserve, but always at the same speed (zero or non-zero) as the latter.

 On the other hand, the outer strand 71 slides on the guide surface 73.

 In practice, this guide surface 73 can be bordered by two raised edges to prevent the turns of the ribbon, generally made of plastic or other relatively slippery material, from falling out of their winding.

 It should be noted that the endless belt 7 can be fixed relative to the crew 6 and in this case, the cylinders 75, 76 do not rotate.

 The strip 7 can also rotate and in this case, the cylinders 75, 76 also rotate.

 In principle, the two cases are distinguished by the blocking of the cylinders 75, 76 in the first case and their release allowing rotation in the second case.

 In practice, if there is blocking of the cylinders in the first case, their release alone is not enough because of the friction of the various elements of the installation, so it is necessary to drive the cylinders in the second case.

The purpose of the receiving drum 5 being to receive tape to temporarily store it, it is necessary to clearly distinguish three means composing the drum 5 to facilitate the description of the invention - the reserve 8: it rotates in the direction of the arrow A to
receive ribbon 2 (part of ribbon 21) arriving at the vi
scroll size V1:
depending on the case, the ribbon 2 (22) may or may not be unwound from the coil
interior of the reserve 8 - the receiving crew 6 formed by the strip 7 and the cylinders
75, 76,
generally rotates around the axis O
remains fixed relative to the axis O - the band 7 can
turn on its way (cylinders 75, 76 turning equal
slightly)
stay fixed.

 The three means can remain fixed with respect to each other and generally rotate with the drum 5 around the axis O; they can also rotate with respect to each other, some of the means having a zero absolute speed.

 These different cases will be described below and they correspond to the real operating cases of the receiving drum 5.

- Accumulation mode: the drum receives tape (2).

 The drum 5 generally rotates along the arrow A around the axis O; the crew 6 is fixed relative to the drum 5 and the strip 7 is stationary relative to the drum 5.

 The ribbon 2 (21) is wound on the drum 5, that is to say the strand 71 of the ribbon 7, it accumulates, constituting the reserve 8.

 The ribbon cannot be unwound from the interior of the reserve 8; the ribbon portion 22 is at a fixed speed relative to the drum.

- Transfer mode: the drum 5 provides ribbon (2).

 The arrival of ribbon 2 (21) is stopped; the drum 5 is fixed, that is to say that the reserve 8 is fixed, immobile.

 The reserve 8 is unwound from the inside by the extraction of the ribbon part 22.

 For this, the crew 6 rotates relative to the reserve 8: the outer strand 71 remains fixed, but the cylinders 75, 76 rotate on themselves and around the axis O; the inner strand 72 also runs.

 The slot 74 then rotates around the axis O and the ribbon 22 unwinds from the interior of the reserve 8.

- Reception mode with transfer: drum 5 receives and
provides ribbon.

 In this case, the ribbon 2 (21) arrives at the non-zero speed V1 (also also lower than the feed speed V3 of the machine 3).

 The drum, that is to say the crew 6 rotates around the axis O in the direction A, that is to say that the cylinders 75, 76 rotate around the axis O, but at the same time time the strip 7 scrolls in the direction of arrow A to unwind the reserve 8 from the inside.

 The reserve 8 increases, remains stable or decreases according to the difference in the arrival and unwinding speeds.

 FIG. 2B makes it easier to understand the operation of the receiving drum 5, of which it shows a slightly different position corresponding to the unwinding of the reserve 8 by the mobile assembly 6.

 According to FIG. 3A, the transmitting drum 9 has a structure close to that of the receiving drum. The sending drum 9 is placed coaxially (axis O) inside the receiving drum 5, in the place left free by the return strand 72 of the endless belt 7 (FIG. 7).

 The transmitter drum 9 is fixed. I1 comprises a transmitting crew 10, fixed, formed by an endless band 11 describing a path in the form of C. This path consists of an outer strand 110 and an inner strand 111 or return strand. The outer strand 110 follows a circular guide 112 interrupted by a slot 113 to allow the outer strand 110 to join the inner strand 111.

 The slot 113 is bordered by two cylinders 114, 115 around which the strip 11 passes. These cylinders are movable in rotation about their axis, but they do not rotate around the axis O.

 The inner strand 111 is advantageously supported by rollers or better by a circular guide surface 116.

 The transmission equipment 10 also comprises an outlet rod 13 receiving the strip 25 unwound from the inner turn 24 of the reserve 12 to supply the strip 26 to the machine 3.

 The structure and operation of the sending drum 9 are simpler than those of the receiving drum 5.

 In fact, the transmission equipment 10 remains fixed in space and only the strip 11 rotates at the speed at which the ribbon must exit the accumulator.

 The ribbon arrives on the transmission drum through the part 23 which is wound on the reserve turns 12 or turns turning in the direction of arrow C, the rotation drive being effected by the circulation of the ribbon 11 itself surrounded by the cylinder or cylinders 114, 115. But at the same time as the crew 10 wraps tape on the reserve 12, it also takes it up by unwinding the reserve 12 from the inside and by extracting tape through the interval 113.

 Insofar as the strip portion 23 arrives on the reserve 12 at the same place, as the crew 10 is fixed, the reserve 12 neither increases nor decreases.

 However, according to the relative speeds and the operating phase of the buffer accumulator, the portion of ribbon 23 unwound from the receiving drum 5 can move as shown in the position shown in FIG. 3B.

 The outer strand 110 or receiving strand receives the ribbon 23 to form an emission reserve 12 composed of a certain number of turns. As previously, by convention, the emission reserve 12 is not shown directly attached to the outer strand 110 but leaving a certain interval.

 In reality, the reception drum and / or its mobile equipment 6 rotate around the transmission drum 9 and the difference in speed with the speed of rotation of the reserve 12 increases or decreases the volume of this reserve 12.

 In fact and schematically, the ribbon reserve is transferred from the reception drum 5 to the transmission drum 9 which supplies the machine with power during the reel change.

 Not shown, the receiving drum 5 and the transmitting drum 9 comprise drive and control means ensuring the rotational drive and the servo-control of the different mobile means at set speeds, each with respect to to others to perform the operation of the buffer accumulator according to the invention. The drive means can be separate motors, associated with the means or groups of drum drive means, but also motors combined with differentials.

The servo means are combined with detection and measurement means controlling the drive means to build up the reserve of tape on the take-up drum as a function, for example, of the time required for each reel, then control it at different relative speeds. to pass the reserve on the transmission drum and feed without interruption or slowing down, the machine.

 The operation of the buffer battery will be repeated briefly below based on Figure 1 which combines all the parts of the buffer battery.

 The ribbon 2 passes from the internal turn of the reception reserve (internal turn marked with the reference 22), through the slot 74 passing for example over the cylinder 76 to arrive via the ribbon segment 23 on the emission reserve 11 .

 In the same way, the emission reserve 12 is unwound from inside the reserve, by the turn schematically carrying the reference 24. The ribbon passes in the interval 113 of the emission crew 10, ensures the passage between the outer strand and the inner strand.

 At the outlet, the strip passes over a guide 13 which deflects the section 25 of the ribbon to give it the direction of the section 26 going towards the processing machine 3.

In normal operation, the buffer accumulator operates as follows
From the reel 1, the ribbon 2 is unwound at the running speed V1 on the receiving drum 5 which rotates around the axis O. The crew 6 rotates inside the drum 6 so that the strip without end 7 can unwind the inner coil of the reserve 8.

 The ribbon 23 arrives on the emission reserve 12.

This reserve is itself driven in rotation by the circulation of the endless belt 11 which, at the same time, unwinds the inner coil (belt parts 24, 25) to supply the machine 3.

 In normal operation or steady state, the speeds V1, V2, V3 are equal. There is no increase or decrease in reserves 8 and 12.

 On the other hand, to constitute the reception reserve, the external drum 5 rotates more quickly to unwind the supply reel 1, at a speed V1 greater than the speed V3 of use of the ribbon by the machine 3. The choice of speed V1 with respect to the speed V3 is made to save the time necessary to change the coil.

 When the reel 1 is empty, the drum 5 is stopped; the running speed V1 of the section 21 of ribbon is canceled; the ribbon 21 is stopped.

 During this time, the reserve 8 continues to be unwound from the inside by the rotation of the crew 6.

 This rotation of the crew 6 is such that the speed of the outer strand 71 in contact with the inner turn of the reception reserve 8 is zero; as the reserve 8 does not rotate, the outer strand 71 is itself fixed; the crew 7 rotates with its cylinders 75, 76 inside the fixed outer strand 71. The slot 74 and the rollers 75, 76 move around the axis O.

 During this time, the emission crew continues to unwind the emission reserve 12 by taking the interior turn 24.

 By definition, reserves 8 and 12 are gradually exchanged, then operations start again with the new coil.

 Depending on the nature of the materials constituting the ribbons, the length of the coils, etc., it is possible to choose an operation of the accumulator with a normal step intersected with the approach of the end of the supply coil by a faster step for load the reception reserve then transfer this reception reserve to the transmission reserve. It is also possible not to operate in normal operation but in accelerated operation to unwind the supply reel, as soon as the operation of the external drum resumes in order to have a greater safety margin for changing the reels.

Claims (4)

10) Buffer accumulator intended to be mounted in a processing line using a ribbon-shaped product supplied by a coil and supplying the processing machine without interruption during the coil change, characterized in that it comprises A) a rotary receiving drum (5),  - provided with a receiving equipment (6), rotatable relative to the drum (5) formed of an endless band (7) describing a circular path in C, by its outer strand (71) and leaving an entry gap (74) to form a reserve (8) of winding receiving the ribbon on its outer turn and unwinding it through its inner turn, passing through the gap (74),  - the endless belt (7) being movable relative to the crew (6), B) a stationary transmitting drum (9) fitted with an emission equipment  (10), fixed,  - formed of a moving endless band (11) describing a circular C-shaped path, followed by the outer strand (110) with passage interval (113) to form on the outer strand (110) a reserve (12) winding receiving the ribbon on its outer turn and unwinding it through its inner turn through the gap (113). C) the transmitter drum (9) being placed coaxially with  the interior of the receiving drum (5), D) drive and control means for driving  the receiving crew (6) and / or the reception bands (7) and  emission (ll), E) the path followed by the ribbon unwound from a passing reel (1)  on the receiving drum (5) to form the cons turns  setting up a reception reserve (8) on the outer strand  (71) of the band (7) of the receiving crew (6), the turn  interior of this reserve (8) unwinding through the  slot (71) of the receiving crew (6) and passing over the  transmission drum (9) to form on the outer strand of  the transmission crew (10), turns constituting a re  serve as emission (12) from which the inner coil is unwound  to be extracted through the crew slot (113)  transmission (10) and supply the machine (3),  - the reception reserve (8) being formed during the unwinding of the reel (1) to constitute a reserve of time necessary for changing the reel,  - This reception reserve (8) being transferred to the transmission reserve (12) during the stopping of the supply to the reception reserve (8) during the change of coil (1). 20) Buffer accumulator according to claim 1, characterized in that the receiving unit (6) and / or transmitter (9) comprises a guide surface (73, 112) in the form of a circle interrupted by a slot (74, 113) bordered by cylinders (75, 76, 114, 115) forming the circular path in C for the outer strand (71,110) of the strip (7,11), the inner strand (72, 111) penetrating through the slot (74,113 ) inside the guide surface to follow its internal contour. 30) Buffer accumulator according to claim 2, characterized in that the receiving unit (6) and / or transmitter (9) comprises a guide surface (77,116) for supporting the inner strand (72,111) of the ribbon. 40) Buffer accumulator according to claim 2, characterized in that the guide surfaces (73,112) are provided with edges to form a path receiving the outer strand (71,110) of the endless ribbons (7,11) and the reserves (8, 12).