GB2058022A - Web feeding and roll changing apparatus - Google Patents

Abstract

A web feeding and web roll changing apparatus has two supply reels (28) carried by support plates (1, 111) and from which the webs may be fed alternately. The apparatus has means to change over from one reel to the other, and a store of further reels (127) from which a fresh reel may be taken to replace each supply reel as necessary. The supply reels may be carried on shafts (11, 111) projecting from plates (1, 101). The plates are alternately in a vertical position while web is being fed from that supply reel or can be swung down to a horizontal position to receive a fresh reel from the top of a stack, the store comprising two such stacks on respective lifting tables (122). <IMAGE>

Description

SPECIFICATION Web feeding This invention relates to web feeding apparatus, particularly, but not necessarily exclusively, for supplying paper, foil and other wrapping materials to machines for packing and for wrapping articles such as cigarettes.

Current cigarette packing machines operate at speeds well in excess of 200 packets per minute and so consume matrial at such a rate that supply reels need replacement at relatively short intervals. If the machine has to be stopped every time a new reel has to be provided, it is easily possible for the machine to be idle for a substantial time, which is clearly uneconomic.

It has been common for some time to provide two reels of required web material on such machines, with provision for automatic changeover as each reel becomes exhausted. But the cost and speed of modern machines now requires facilities to continuous web supply for periods of several hours, preferably a whole working shift, without an operator having to load fresh reels.

According to one aspect of the invention, there is provided a web feeding apparatus comprising means for supporting two supply packs of web material for delivery of web therefrom, means for stopping supply from a first one of said packs and starting supply from the second of said packs so that web delivery is uninterrupted, and a store for further supply packs including transfer means for moving a further supply pack from said store to replace each of said two supply packs after supply from the latter has been stopped.

While units embodying the invention are at present preferably arranged to handle supply packs in the form of reels, such units may alternatively be adapted to use supply packs in the form of boxes containing web material folded in zig-zag (concertina) fashion.

In a preferred arrangement each supporting means are a pair of carrier plates each having an expansible collet mounted on a shaft projecting therefrom, each carrier plate being mounted to swing between a reel feeding position in a vertical plane and a reel transfer position in a horizontal plane, said store comprising two vertically movable tables one associated with each carrier plate and each being arranged to support a stack of reels with their axes vertical, and means for moving each table to bring the uppermost reel of the stack thereon towards the respective carrier plate at said transfer position, so that the core of the reel surrounds the expansible collet.

Thus the collet may be expanded to grip the core of the reel, and the plate then swung to its reel feeding position, carrying the reel with it.

According to a second aspect of the invention the means for moving said table to bring the reel to the transfer position comprises a retaining member for receiving the free end of web projecting from the reel, and means for moving said retaining member in synchronism with movement of said table so that the free end of web is kept in a defined position relative to the reel.

Conveniently said retaining means in a spring clip, and the means for moving said clip is a chain to which said clip is attached. In a preferred arrangement, a succession of such clips are secured at regular intervals to a straight run of chain extending vertically, alongside the stack of reels (with their axes vertical) on said table.

According to a third aspect of the invention, said carrier plate is provided with a web clamp, comprising two rotatable rollers mounted with their axes parallel, at least one of said rollers being movably mounted so that the space in between the rollers is variable, and at least one of said rollers incorporating a free-wheel so that it is rotatable in one direction only.

The web clamp may be mounted on the carrier at such a distance from the collet that the clamp is spaced from the periphery of the largest diameter reel which may be retained by the collet.

When a fresh reel is being transferred to the collet the rollers of the clamp are held apart to allow the leading end of the web from the fresh reel to enter between said rollers, and then the rollers are brought together to grip said leading end. The free-wheel is arranged to prevent said leading end, once gripped, from moving back towards the reel, but to permit said leading end to move away from the reel as is required once the carrier has been moved with the fresh reel to the feed position.

According to a fourth and final aspect of the invention, there is provided a web feed device comprising a pair of endless belt conveyors each having a straight working run disposed closely adjacent and parallel to the working run of the other so as to grip a web therebetween, and means for driving said belt conveyors so that both said working runs advance at the same speed to feed any web so gripped, the conveyors at the upstream end of said working runs being carried on guide rollers so mounted that they may be separated to allow a leading end of the web to be placed between the working runs, the leading end not being gripped until the guide rollers are brought together.

Use of said device permits a fresh reel to be placed in position, with the leading end of the web therefrom between the working runs of the belt conveyors, but without driving the web forward until web feeding from another reel is about to become exhausted, whereupon feed of web from the fresh reel or pack may be started by bringing together the guide rollers and driving the belt conveyors. There is no need to stop the belt conveyors, provided the web is made of material not liable to damage if rubbed against a moving belt; but if such damage is possible and is to be avoided, the belt conveyers may be stopped while web feed is not desired, and the drive may be smoothly taken up afterthe guide rollers are broughttogether, so thatthe leading end of web is gripped, by progressive engagement of a clutch providing drive connection to said belt conveyor.

The separation of the guide rollers is preferably obtained by movement of the guide roller for one belt conveyor only, and this roller is preferably some distance upstream of the upstream guide roller for the other belt conveyor. This enables the movable guide roller to bring the upstream end of one belt conveyor into and out of nipping relation with one of the pair of rollers serving as a web clamp to hold the leading end of the web; this arrangement helps to ensure feed of the web even if said leading end does not project far enough towards the working run of the belt conveyors to be sufficiently gripped therebetween when feeding is required to start.

In order that the invention may be well understood, a preferred embodiment thereof will now be described with reference to the accompanying drawings, in which: Figure lisa front elevation of a web feeding apparatus embodying the invention; Figure 2 is a side elevation of the apparatus of Figure 1; Figure 3 is a rear elevation of said apparatus; Figure 4 is a detail view looking in the direction as indicated by the arrows IV-IV of Figure 1; and Figure 5shows a detail of a knife guard.

In the following description, a web feeding apparatus or unit is described in which many elements are duplicated, as the unit has provision for holding two reels of web in position for feed of web therefrom, and for each reel when exhausted to be replaced with a fresh reel from a respective one of two stacks of reels. For such duplicated elements, the reference number where applied to the element in the righthand part of the unit (as viewed in Figure 1 ) is one hundred greater than the reference number for the corresponding element in the left-hand part of the unit.

As shown in Figures 1 to 3, the unit includes two identical carrier plates 1,101, both being mounted in the upper part of the unit with the plate 1 at the left and the plate 101 at the right (as seen in Figure 1).

Each of the plates 1, 101 is swingably mounted on pairs of upper links 2, 102 and pairs of lower links 3, 103 between an upper (vertical) position (as plate 1 is shown) and a lower (horizontal) position (as plate 101 is shown). The upper links 2, 102 are straight bars, pivoted at one end to lugs 4, 104 on their respective plates 1, 101 and at the other end to fixed anchorages 5, 105. The lower links 3, 103 are of bell crank or triangular form, pivoted at one corner to lugs 6, 106 on their respective plates 1, 101, at another corner to fixed anchorages 7, 107, and at the third corner to rams 8, 108 of hydraulic cylinders 9, 109, which cylinders are carried pivotally on fixed members 10,110.

Each of the plates 1, 101 carries a spindle 11, 111 projecting through the plate at right-angles to its faces and located slightly above the centre of the plate (considering the plate in its vertical position).

Behind the plate, each spindle 11, 111 is provided with an electromagnetic brake (not shown), and in front of the plate each spindle carries an expansible collet 13, 113 and also an ejector ring 14,114 supported on sprung mountings 15, 115which lightly urge the ring away from the plate. Each of the plates 1,101 is also provided with a knife assembly 16, a web guide roller 17, a pair of web clamping rollers 18, 19 and an upwardly-directed optical reflector 20 (each of such right-hand parts not being shown).

In the lower part of the unit there are two vertical feed-screws 21,121 journalled at their lower ends so as to be respectively coaxial with the spindles 11, 111 when the latter are vertical, i.e. when plates 1, 101 are in their lower positions. Each of said feed-screws carries a table 22, 122, the tables having tapped holes in which the feed-screws are engaged so that rotation of either feed-screw causes the associated table to rise or fall. Near its lower end each feed-screw carries a bevel gear 23, 123 meshed with a coacting gear 24, 124 which is rotatable by an electric motor (not shown).

In use, each table carries (coaxial with its feed screw 21,121) a stack of reels 27,127 of web material, e.g. wrapping foil. The topmost reel can be placed on the respective spindle 11, 111 by the following sequence of operations: the respective plate 1, 101 is swung to its lower position, so that its spindle 11, 111 points vertically downward in alignment with feed-screw 21, 121; the respective feedscrew is rotated by the motor driving through the gears 23,24,123, 124, to lift the table 22,122 until the core of the topmost reel 27, 127 is at the level of the collet 13, 113;; the collet is then expanded to grip the reel core and the plate is swung to its upper position, bringing the reel thus removed from the stack to the position of the reel 28 (Figure 1) for feed of the web from the reel.

In the sequence of operations just described, the free end of web on the outside of each reel must be controlled to remove the need for manual threading of web from the reel after it has reached the position of the reel 28 (Figure 1). Alongside and parallel to each feed-screw 21, 121 is a run of chain 29, 129 arranged to move with the table 22, 122, and carrying regularly spaced projecting spring clips 130 (Figure 2). The clips for the left-hand part of the unit are not shown. When reels are stacked on tables 22, 122, as each reel is added to the stack the free end 31,131 of web from that reel is unwound a sufficient distance and inserted into the clip 130 at the level of the reel.

When the reel is brought up to the level of the collet 13,113 (with the plate 1,101 in its lower position), the clamping roller 18 is not in the position shown in Figure 1 but has been moved clockwise about a pivot 1 8A so that there is a gap between the rollers 18 and 19, and the free end 31, 131 of web is held by the clip 130 in such a position that it becomes between the rollers 18 and 19 as the reel comes to the level of the collet 13, 113. When the collet is expanded, the roller 18 is moved anticlockwise to the position of the roller shown in Figure 1, to grip the free end 31, 131 of the web. Thus as the plate 1, 101 swings to its upper position, the end of the web is pulled out of the clip 130. One of the clamping rollers of each pair 18, 19 embodies a free-wheel, allowing rotation of the roller when web is moving away from the reel but preventing rotation in a sense permitting the web to pull back towards the reel.

When a reel has been brought to the position of reel 28 (Figure 1), it is brought into use when required and web from the reel is then pulled from the reel by upper and lower driven belts 32, 33 which have adjacent parallel runs between which the web is gripped. The lower belt 33 has its upstream end projecting beyond the end of belt 32 and carried by a guide roller 34 which is moveable by a pneumatic cylinder 35. In the raised position adjacent runs of the belts 32, 33 are together and the roller 34 presses belt 33 against clamping roller 19. The free end 31 of web from the reel, projecting from between rollers 18, 19, is therefore gripped between the belt 33 and roller 19 and driven between belts 32,33.As seen in Figure 1, while web is thus feeding from reel 28 it passes around a guide roller 36 on the knife assembly 16, around a guide roller 37 on an arm 38, then around the fixed guide roller 17, a further roller 39 also on arm 38, and then to the rollers 18, 19. The arm 38 is swingable on a pivot 40 and is resiliently biased by a spring 41 to balance the tension in web passing round rollers 37,39. A pneumatic cylinder 42 is coupled to a pivoted arm 43 which is engageable with the arm 38 when the cylinder 42 is actuated to push arm 38 to its most clockwise position against a vertical stop 44.The arm 38 is thus pushed clockwise (to the position in which the right-hand arm 138 is shown in Figure 1) before the plate 1 is swung from its lower to its upper position after receiving a fresh reel from the stack, and the rollers 37,39 are thus moved to the right of the direct path of web from the reel to clamping rollers 18, 19. Once the plate 1 is in its upper position, actuation of cylinder 42 is discontinued and the spring 41 brings the arm 38 back to about the position shown, establishing the web path around rollers 36,37, 17,39 as shown.

It will be noted that while the belts 32,33 are disposed to convey web from reel 28 carried by the plate 1 downwardly to the right, the slope of corresponding belts 132, 133 associated with the plate 101 is downwardly to the left (as seen in Figure 1). The two sets of belts converge in the region indicated by arrow X; upper belts 32, 132 terminate here, at guide rollers 45, 145, and lower belts 33, 133 terminate a little lower at guide rollers 46, 146. From the rollers 46, 146 further belts 47, 147 extend via guide roller assemblies 48,49 to deliver web to a web-consuming machine (e.g. a packing machine not shown).It should be noted that the belts 32, 33, 132,133,47,147 are not full-width belts, but are each a set of spaced narrow belts; this allows rollers 46, 146 to carry both the downstream ends of belts 33, 133 and the upstream ends of belts 47, 147, the narrow belts of one set being interdigitated with those of the other set.

The knife assembly 16 is shown in more detail in Figure 4. A single blade 50 is pivoted near the base of the guide roller 36 and a pneumatic cylinder 51 is coupled to said blade so that actuation of said cylinder causes the blade 50 to pivot clockwise to cross the path of web approaching roller 36 from reel 28 to cut said web. Such a cut is required when the reel 28 reaches a minimum diameter and it is desired to stop feed of web from said reel and commence feed of web from another reel supported on carrier plate 101 (in its upper position).

The reel diameter is sensed by an optical detector 52, fixedly mounted above each carrier plate to co-operate with the reflector 20. The detector 52, includes a light source which projects a light beam downward and a photo-electric transducer for receiving the beam after reflection by the reflector 20.

The detector and reflector for each carrier plate are so placed that a reel carried on said plate prevents light from the source reaching the reflector, and thereafter the transducer, as long as that reel is of greater diameter than the predetermined minimum.

Once light reaches the transducer, a signal therefrom causes the knife cylinder 51 to to actuated.

However, there is normally a delay before such actuation because, at the time of cut, it is required that there shall be a predetermined length of web between the knife and the guide roller 46, 146. To achieve this, the signal from the transducer initially causes a progressive energisation (by a "ramp" voltage) of the brake for the reel 28 from which web is being fed, and the resulting increase in web tension causes the arm 38 to move clockwise; at a preselected position said arm operates a switch (not shown) which controls application of the transducer signal to cause actuation of the cylinder 51.When said signal is thus applied to cause actuation of cylinder 51, it also causes a counter (not shown) to commence receiving electric pulses from a pulse generator driven by roller 46, 146. At a predetermined count, logical circuits associated with the counter emit a control signal causing cylinder 35 to move guide roller 34 of belt 33 away from roller 19 and cylinder 135 to move guide roller 134 of belt 133 into nipping engagement with the right-hand roller corresponding to the roller 19, so as to feed new web from a reel on carrier plate 101.

It will be understood that by proper choice of the count at which said control signal appears, the leading end of the new web can be fed into the belts 47, 147 at a desired position relative to the trailing end of the preceding web i.e. with a desired overlap or with none. With the arrangement shown wherein web is fed between belts 47, 147 it is normally preferred to feed web from each reel with no overlap relative to web from the preceding reel. As an alternative, however, a splicer may be provided below rollers 46, 146, and the belts 47, 147 may be omitted since, when the ends of web from successive reels are spliced together, the continuous web may be fed merely over suitably placed guide rollers.

With this alternative arrangement it may be required (depending upon the type of splicer used) to feed the preceding reel. Operation of the splicer may conveniently be initiated by a signal derived from the counter when a second predetermined count is reached.

When the reel 28 has reached minimum diameter and the web therefrom has been cut by blade 50, the reel core is ejected from the collet 13 before the carrier plate 1 moves to its lower position to collect a fresh reel. For ejection of the core, the collet 13 is caused to contract after the web has been cut, and the sprung mountings of the ejector ring 14 push the latter forward so that the reel core is ejected. A guard (not shown) is normally fitted over the front of the unit to prevent access to the mechanism during operation, and it is preferred that the interior of this guard be formed with chutes disposed to receive reel cores from each of the collets 13, 113 and guide them down to a receptacle formed in the lower part of said guard.

It should be noted that the reels handled by such a unit may be of considerable weight. To relieve the load on the links which support the carrier plates, constant-tension spring units are attached to the upper links 2, 102 close to their pivoted connection to the lugs 4, 104. The units are preferably "Tensator" units manufactured by Tensator Limited, of Tichford Street, Newport Pagnell, Buckinghamshire, and take the form of a strip 60, 160 of springy metal which, when not pulled, lies in a spiral in a casing 61, 161. The force required to pull the strip from the casing is constant, whatever length of strip is already outside the casing.As best seen in Figure 2 the casings 61, 161 are fixedly mounted at the top of the unit in such positions that the strips 60, 160 extend substantially vertically from their attachments to the links 2, 102.

When a fresh reel is to be placed on the spindle of one of the carrier plates, as above described, the respective table 22, 122 is raised by rotation of screw 21, 121; convenientlythe rise ofthetable is halted at an appropriate distance from the carrier plate by a signal from a proximity detector (not shown) mounted on the plate, or to one side of the stack of reels on the table.After the collet 13, 113 has expanded to grip the fresh reel, and before the plate swings to its upper position, the table 22, 122 is lowered slightly (by reverse rotation of screw 21, 121) to ensure safe clearance between the top of the stack of reels left on the table and projections on the front face of the carrier plate, i.e. the fresh reel itself, knife assembly 16, and rollers 17, 18, 19. It can be seen from Figure 2 that the upper and lower links on which each carrier plate is mounted are so arranged that, on leaving its lower position, the motion of the plate has a vertical component larger than its horizontal component and this helps to produce the safe clearance.

It is desirable to provide some warning indication when either of the stacks of reels on tables 22, 122 is exhausted. Conveniently a microswitch may be fitted in each table, arranged to be held open when one or more reels in on the table and in the absence of even one reel to close a circuit to energise a warning light or other alarm device.

The knife assembly 16 presents a hazard for operators and maintenance engineers when the front guard of the unit is open. It is preferred therefore to provide a safety latch for each knife assembly, for example (as shown in Figure 5) a slidable guard 54 biased by springs (not shown) towards the left so that when it is free to move to the position shown in dotted line, knife blade 50 cannot move in the cutting direction indicated by arrow 55.

A latch 56 secured to a part of the front guard 57 holds the knife guard 54 in the position shown in full line, clear of the blade 50, when said guard is closed so that movement of the blade 50 is not hindered.

The take-up of web between the belts 32,33 or 132,133 may be immediate whenever the upstream end of the lower belt is raised, the belts being driven all the time even when they are not feeding web.

Alternatively (and preferably if the web being fed is of material whose surface may be damaged by slip between the belts and web as the upstream end of the lower belt is raised) there may be a clutch in the drive to the belts 32,33 which is disengaged when the upstream end of belt 33 is lowered and is not engaged until said upstream end is fully raised so that the web is gripped between the belts so that slip does not occur. The clutch may then be progressively engaged to take up drive of the web without jerking, e.g. an electromagnetic clutch energised by a progressively increasing ("ramp") voltage may be employed.

Claims (11)

1. A web feeding apparatus comprising means of supporting two supply packs of web material for delivery of web therefrom, means for stopping supply from a first one of said packs and starting supply from the second of said packs so that web delivery is uninterrupted, and a store for further supply packs including transfer means for moving a further supply pack from said store to replace each of said two supply packs after supply from the latter has been stopped.

2. Apparatus according to claim 1 in which the supply packs of web material are in the form of reels each having an open core formed at the centre thereof.

3. Apparatus according to claim 2 in which the supporting means are a pair of carrier plates each having an expansible collet mounted on a shaft projecting therefrom, each carrier plate being mounted to swing between a reel feeding position in a vertical plane and a reel transfer position in a horizontal plane, said store comprising two vertically movable tables one associated with each carrier plate and each being arranged to support a stack of reels with their axes vertical, and means for moving each table to bring the uppermost reel of the stack thereon towards the respective carrier plate at said transfer position, so that the core of the reel surrounds the expansible collet.

4. Apparatus according to claim 3 in which the means for moving said table to bring the reel to the transfer position comprises a retaining member for receiving the free end of web projecting from the reel, and means for moving said retaining member in synchronism with movement of said table so that the free end of the web is kept in a defined position relative to the reel.

5. Apparatus according to claim 4 in which said retaining means is a spring clip, and the means for moving said clip is a chain to which said clip is attached.

6. Apparatus according to claim 5 in which a succession of such clips are secured at regular intervals to a straight run of chain extending vertically, alongside the stack of reels on said table.

7. Apparatus according to any of claims 3 to 6 in which each said carrier plate is provided with a web clamp, comprising two rotatable rollers mounted with their axes parallel, at least one of said rollers being movably mounted so that the spacing between the rollers is variable, and at least one of said rollers incorporating a free-wheel so that it is rotatable in one direction only.

8. A web feed device comprising a pair of endless belt conveyors each having a straight working run disposed closely adjacent and parallel to the working run of the other so as to grip the web therebetween, and means for driving said belt conveyors so that both said working runs advance at the same speed to feed any web so gripped, the conveyors of the upstream end of said working runs being carried on guide rollers so mounted that they may be separated to allow a leading end of the web to be placed between the working runs, the leading end not being gripped until the guide rollers are brought together.

9. A web feed device as claimed in claim 8 in which only one of the guide rollers is movable for separation from the other roller, said one roller being spaced upstream of the upstream guide roller for the other belt conveyor.

10. A web feeding apparatus substantially as herein described with reference to, and as illustrated in, the accompanying drawings.

11. A web feed device substantially as herein described with reference to, and as illustrated in Figures 1 and 2 of the accompanying drawings.