GB2142609A

GB2142609A - Splicing webs

Info

Publication number: GB2142609A
Application number: GB08412123A
Authority: GB
Inventors: Jean Francois Ballet
Original assignee: Colgate Palmolive Co
Current assignee: Colgate Palmolive Co
Priority date: 1983-05-12
Filing date: 1984-05-11
Publication date: 1985-01-23
Also published as: FR2545801B1; GB8613951D0; FR2545801A1; GB2186866A; GB2186866B; GB2186271B; BE899652A; GB2142609B; AU2787784A; GB8613950D0; GB8412123D0; AU560080B2; GB2186271A

Abstract

Sheet or web material is spliced by two frames (19A,19B) which are each mounted to rock between an operative position (frame 19A as shown) and a stand-by position (frame 19B) and a movable driving roller (22) which is brought into cooperation with a discharging roller (21) during splicing. The frames (19A,19B) are pivoted together when the webs are to be spliced by an adhesive band (38). The adhesive band (38) joining the webs is then detected by a photocell (23) which actuates cutter (29A) to sever the expiring web. Each frame (19) comprises an input roller (24) and an output roller (25). The nip formed at rollers (21,22) during splicing isolates any jerks in the motion of the webs from the downstream section of web and the driven roller (22) facilitates the web cutting, particularly in fragile and/or extensible webs. The web supply rolls (20A,20B) can be driven by an endless belt and the web may pass through a buffer device. <IMAGE>

Description

SPECIFICATION A machine for unwinding and automatically connecting sheet material The present invention relates to a machine for unwinding and automatically connecting sheet material which is carried by two reels which are put alternately into operation.

When it is desired to continuously unwind at a high rate fragile and/or extensible products, reel changing presents serious problems if it is desired to avoid as far as possible waste and to avoid disturbing the operation of the treating installation located on the downstream side of the machine, which installation may for example serve to manufacture disposable napkins or diapers for babies. Heretofore it has only been possible to automatically feed a new reel of material which leads to breakdown and discontinuity of operation.

The present invention aims to provide a simple and compact machine which is capable of meeting these requirements in a satisfactory manner.

According to the present invention there is provided an unwinding and automatic connecting machine for sheet material which is carried by two reels, the said machine comprising two frames mounted to be rockable between an operative position and a stand-by position. Each frame comprises at least one input roller and an output roller, a discharging roller, a driving roller adapted totem- porarily cooperate with the discharging roller, and a guiding device for guiding a sheet which leaves the output roller toward the nip gap between the discharging roller and the driving roller when the corresponding frame is in the operative position thereof.

According to advantageous features of the present invention each frame comprises cutting means disposed between the input roller and the output roller, the said cutting means being controlled if desired by a photoelectric cell which is disposed downstream of the discharging roller. The machine preferably comprises a driving device for the periphery of the reel associated with each frame, the two peripheral driving devices being adapted to rotate at the same peripheral speed and each being capable of coming selectively into engagement with the corresponding reel.

The invention may be put into practice in various ways and one specific embodiment will be described to illustrate the invention with reference to the accompanying drawings, in which: Figure 1 is a diagrammatic assembly view of an unwinding and automatic connecting machine according to the invention; Figure 2 is a diagrammatic view of the device for driving the reels of the said machine, this view being in the opposite direction to that of Figure 1; Figure 3 is a diagrammatic view of the connecting device of the machine; and Figure 4 is a diagram of the motor control circuit.

The unwinding machine shown in Figure 1 is adapted to deliver continuously a sheet of a material such as polyethylene, non-woven fabric, cellulose, etc., to a treating installation (not shown) located on the downstream side of the machine. The unwinding machine comprises a double unwinder device 1, a connecting device 2 and a device 3 for controlling the tension in the material being unwound.

The unwinder 1 comprises two reel-carrying shafts 4A, 4B (which in use carry reels 20A and 20B) with which there are associated a belt driving device 5A, 5B and an empty reel detecting device 6A, 6B.

The devices 1 and 2 are mainly symmetrical relative to the two reels which are being considered.

Consequently, hereinafter, the letter "A" or "B" will be assigned to the same element relating to the two respective reels and these letters will be omitted for designating any one of these two elements.

As can be seen in Figure 2, each driving device 5 comprises a set of two pulleys 7,8 around which a belt 9 extends. The shafts of the two pulleys are carried by a rigid frame 10 which is pivotally mounted on the shaft of the lower pulley 7. A driving pulley 11 is keyed on this shaft and is connected selectively by a lever 14, with possiblity of reversal of the direction of rotation, via a belt or othertransmis- sion means and a pulley 13 to the output means 15 of a transmission 16 driven by a motor 17.

The connecting device 2 (see Figures 1 and 3) comprises two pivotal frames 19A, 19B which are respectively associated with the two reels 20A, 20B, a discharging roller 22 and a photoelectric cell 23.

The roller 22 is also driven by the motor 17 and its speed is proportional to that of the driving devices 5A and 5B.

Each frame 19A, 19B carries two rollers 24, 25 and is mounted to be able to rock about the shaft of the lower roller 24. In use the sheet 26 which is being unwound extends from its reels 20A or 20B and passes around a fixed roller 27 located upstream of the frame 19, and then under the input roller 24, and then around the upper output roller 25 which the sheet surrounds to the extent of almost half its circumference. Between the rollers 24 and 25, the frame carries an anvil 28 in the form of a groove and, on the other side of the sheet 26, a movable cutter 29. A stand-by table 30 is provided downstream of the roller 25. The shaft of the driving roller 22 is carried by a pivotal fork member 31 adapted to pivot as indicated by the arrow.The rollers 21,24,25 and 27 are freely rotatable and the roller 22 is connected to the motor 17 buy a suitable transmission (not shown).

Pneumatic fluid motors or cylinder devices (not shown) control the movements of the frames 10 (see Figure 2) of the unwinder 1, the frames 19 and the cutters 29 of the device 2 and the fork member 31.

The tension controlling the device 3 comprises a tension pulley arrangement 32 which is loaded by a suspended counterweight 33 which imposes a constant tension on the sheet downstream of the cell 23 and compensates for variations in speed and stretch of the sheet within a moderate space, in particular during the connecting operation which will be described hereinafter.

The speed of the motor 17 is regulated by the circuit shown in Figure 4. This circuit comprises a speed variator 34 of the "four-quadrant" type, i.e. of the type which is controlled both when accelerating and when braking. This variator receives three items of the information: over the line 35, a set speed, corresponding to the unwinding required by the downstream installation, which is delivered by a dynamo (not shown) located downstream of the tension pulley arrangement 32; an error signal corresponding to the difference between the real speed of unwinding in the region of the tension pulley arrangement which is deduced from the movements of the counterweight 33 buy a potentiometer 36 connected to the latter, and the set speed.

Lastly, the variator 34 receives a signal corresponding to the real speed of the motor 17 furnished by a dynamo 37 keyed on the shaft of the motor. The variator 34 deduces at each instant from the first two signals the speed required of the motor 17, and the third signal enables this speed to be stabilized by means of a closed loop regulation.

The machine operates in the following manner: At the start, it will be assumed that the reel 20A is in course of unwinding; its sheet 26A passes round the roller 27A, round the roller 24A, round the roller 25A, round the roller 21, in front of the cell 23 through the tension pulley arrangement 32 and then reaches a subsequent treating station (not shown) located downstream of the machine. The roller 22 is separated from the roller 21.The frame 19A is rocked forwardly (to the right in Figure 3) and this brings the portion of sheet located between the rollers 25A and 21 to a vertical position The driving device 5A is lowered into the lower position so that it freely bears against the reel 20A and drives the latter by cooperation of its belts 9A with the periphery of this reel, the synchronization of the speed of this belt 9A and the velocity of the sheet downstream of the tension pulley arrangement being achieved by means of the circuit shown in Figure 4.

At the start the driving device 5B is raised and moved awayfromthe reel 20B, which isfull and in a stand-by condition. The driving device 5B rotates at the same speed as the device 5A. The beginning of the sheet 26B is fed around the rollers 278 and then 24B and around the roller 25B and its free end freely bears on the table 308 and carries on its upper face a double-sided adhesive band 38.

As the diameter of the reel 20A diminishes, the frame 1 OA of the driving device 5A descends until the proximity detector 6A associated therewith initiates the connecting operation which is carried out as foliows.

The roller 22 is brought against the band 26A and drives the latter to the output of the device 2 upstream of the cell 23. The frame 10B descends and commences the peripheral driving of the reel 208 The frame 19B is moved to the left and this brings the adhesive band 38 into contact with the sheet 26A. The two sheets 26A and 26B are then driven together in the nip gap between the rollers 21 and 22.

When the cell 23 detects the passage of the adhesive band 38 by a change in the opacity (or in the reflected luminosity), it actuates the cutter 29A which cuts the sheet 26A and then causes the raising of the frame 1 OA and the retraction to the left of the frame 1 9A and the withdrawal to the left of the roller 22. The reel 20A can then be replaced by a stand-by fuli reel and the unwinding of the sheet 26B follows on the unwinding of the sheet 26A without interruption. The information from the cell 23 is also transmitted to the tension pulley arrangement iocated on the downstream side which automatically eliminates the region of the sheet involved in the connection from the subsequent treatment.

It should be noted that jerks in the motion of the sheet due to the connection of the two sheets are isolated from the downstream side, on one hand, by the positive drive afforded temporarily by the roller 22, and on the other hand, by the tension pulley arrangement 32. Further, the roller 22 pulls on the sheet 26A, which facilitates the cutting, anxd the tension pulley arrangement acts as a buffer device accommodating variations in sheet speed.

The connection between the two reels is thus achieved in a reliable and automatic manner and leaves a minimum amount of product on the empty reel and does not disturb the operation of the installation downstream of the machine. It will be understood that a suitable timing must be provided between the various movements, and in particular between the start of the peripheral drive of the reel 20B and the lowering (moving to the left) of the frame 19B, so as to avoid any damage to the sheet 268. This timing may, in particular, introduce slack in the sheet in the region of the connection, this slack being taken up later by the tension pulley arrangement 32 when the roller 22 returns to the inoperative position.

In order to replace an empty reel and put its leading end in position in the device 2, a corresponding case 39 (see Figure 1) must be opened, and this opening cuts off the pneumatic circuit connected to the associated fluid motor or cylinder device actuating the cutter 29. In this way the safety of the operator is ensured.

The levers 14A, 14B are for disengaging the driving device 5A or 5B when a single reel is desired to be employed, and also for reversing the direction of rotation of a reel when the nature of the sheet material requires this.

Claims

1. An unwinding and automatic connecting machine for sheet material which is carried by two reels, the said machine being provided with sheet connecting means comprising two frames mounted to be movable between an operative position and a stand-by position, each frame comprising at least one input roller and an output roller, a discharging roller, and a driving roller adapted to cooperate temporarily with the discharging roller with a nip gap therebetween, and means for guiding a sheet which leaves an output roller toward the said nip gap between the said discharging roller and the said driving roller when the frame is in the operative position thereof.

2. A machine as claimed in Claim 1 in which the generatrix of the output roller of each frame is above the said nip gap between the said discharging roller and the said driving roller when the frame is in the operative position thereof.

3. A machine as claimed in Claim 1 in which the generatrix of the output roller of each frame is in vertical alignment with the said nip gap between the said discharging roller and the said driving roller when the frame is in the operative position thereof.

4. A machine as claimed in Claim 1,2 or 3 in which each frame further includes a stand-by table located downstream of the said output roller.

5. A machine as claimed in any one of Claims 1 to 4 in which each frame further includes cutting means.

6. A machine as claimed in any one of Claims 1 to 5 in which in each frame the cutting means are disposed between the said input roller and the said output roller thereof.

7. A machine as claimed in Claim 5 or Claim 6, including sensor means, e.g. a photoelectric cell, disposed downstream of the discharging roller and controlling the said cutting means.

8. A machine as claimed in Claim 1 in which the sheet connecting means are substantially as specifically described herein as device 2 with reference to Figures 1 and 3.

9. A machine for unwinding sheet material which is carried by two reels including a reel periphery driving device associated with each frame, the two peripheral driving devices being arranged to rotate at the same peripheral speed and each being capable of being brought selectively into engagement with their associated reel.

10. A machine as claimed in Claim 9 in which each peripheral driving device comprises a belt extending around two pulleys, one of the said pulleys having a fixed axis, the said belt drivingly engaging by the effect of friction the corresponding reel.

11. A machine as claimed in Claim 9 or Claim 10 comprising a device for detecting the diameter of the reel which is being unwound, the said device, on detection of a predetermined condition indicating the reel to be nearly fully unwound, being operative to put the other or stand-by frame into the operative position thereof and to selectively put the other peripheral driving device into engagement with the stand-by reel.

12. A device as claimed in Claim 9 substantially as specifically described herein as device 1 with reference to Figures 1 and 2 of the accompanying drawings.

13. A machine for unwinding sheet material which is carried by two reels comprising at the downstream end thereof, a pulley block tensioning arrangement which imparts a constant tension to the sheet.

14. A machine as claimed in claim 13 in which the said pulley block tensioning arrangement comprises a suspended counterweight associated with a position detector, the speed of the unwinding mechanism being controlled in accordance with the output of the said position detector.

15. A machine as claimed in Claim 13 or Claim 14 substantially as specifically described herein as device 3 with reference to Figure 1 or Figure 1 and Figure 4 of the accompanying drawings.

16. A machine as claimed in any one of Claims 9 to 12 in combination with sheet connecting means as claimed in any one of Claims 1 to 8.

17. A machine as claimed in any one of Claims 1 to 8 or Claims 9 to 12 or Claim 16 in combination with a pulley block tensioning arrangement as claimed in any one of Claims 13 to 15.

18. A machine as claimed in Claim 1 substantially as specifically described herein with reference to the accompanying drawings.