The present invention relates to methods and apparatus for web handling, in particular but not exclusively methods and apparatus for use in separating end portions from a moving web and transporting said end portions away at a speed which is greater than the speed of the web.

When lengths are cut from a moving web of material, they are usually transported for further processing initially at a speed which is the same as that at which the web moves. A need has now arisen for lengths cut from a web to be accelerated rapidly to a higher speed of movement for further processing.

In connection with laminated paper board cartons for containing liquid contents produced by forming a web into a tube, forming a longitudinally running heat seal continuously up the tube and forming spaced heat seals across the tube to close it into a series of pockets whilst simultaneously continuously introducing liquid into the tube, it has been proposed to provide a strip of film or foil heat sealed into the top seal of each package and protruding therefrom which can be pulled by a user opening the package to break the top seal open to form a pouring aperture. To achieve this result it has been necessary to secure the required strips of film or foil in position on the machine used in filling the cartons produced. This however can only be done if the filling machine is substantially slowed down compared to normal operating rates and substantial practical difficulties have been encountered. In particular, it is very desirable that the strip of film or foil used for the opening operation is cut so as to have a sharp clean edge. Otherwise, the strip itself tends to tear across at the location of any nick in its edge when the user tries to open the package. To achieve a clean cut of this kind, it has been necessary to cut the strip from a continuous web of suitable material whilst the web is stationary.

In a first aspect the present invention provides a method for separating end portions of a moving web from the web and transporting said end portions away at a speed which is greater than the speed of the web, comprising supplying said web progressively from a supply at a first speed, feeding the web to bring the free end of the web to the surface of a web support member which surface is moving at a second, greater speed, the web being fed between said supply and a web separation location at said web support member over a path of variable length such that by decreasing said path length between said web supply and said web separation location the end of the web may be accelerated to said second speed without increasing said unreeling speed, accelerating said end portion of said web to about said second speed, separating said end portion of said web from said web at said separation location, and transporting the separated end portion on said support member.

Preferably, the web support member is rotating and said surface thereof is radially outwardly directed. The web support member may therefore be a drum or roller. It is within the scope of the invention however for it to be a continuous belt conveyor, a reciprocating platen or any other moving member capable of supporting a portion of a web.

Optionally, the end of the web is accelerated to said second speed and said path length is caused to vary by the application of means serving substantially to prevent continuance of slippage between said end of the web and said support surface. Whilst said slippage preventing means may be constituted by vacuum ports in the surface and means for applying suction to them to hold the end of the web fast against the surface and by many other alternative means, it is preferably provided in the form of at least one web- pressing member which is advanced to press said end portion of the web against said support surface. Preferably, the web-pressing member is moved at said second speed over a closed curved path, e.g. a circular path,

substantially tangential to the path of the surface of the web support member. The term "substantially tangential" is used herein to include paths which briefly intersect one another. Especially if the paths intersect, it is preferable that the web pressing member is resilient or is resiliently mounted so that it presses in a resilient manner against the web on its support surface while passing over that portion of its path which intersects with the path of the web support surface.

The web-pressing member may be carried on a beam member or bridge member which, on each side of said web-pressing member is eccentrically pivotally mounted to respective rotatable members, whereby synchronous rotation of said rotatable members causes each point along said beam member to execute a similar rotary motion. Preferably, a knife for partially cutting through said web is located adjacent said web-pressing member and is advanced with it. Preferably, said knife is also carried on said beam member adjacent said web-pressing member.

More generally, the method more preferably comprises moving a knife for partially cutting through the thickness of said web at said second speed over a closed path substantially tangential to the path of the surface of the web support member. Preferably, the knife is carried on a beam member of the kind described previously, whether or not a web-pressing member is also present there.

The knife preferably comprises a blade and at or beyond each end of said blade a respective buffer member, said buffer members contacting the surface of the web support member when the knife is in a cutting position with respect to said web support surface and serving to limit the approach of said blade towards to web support surface.

To avoid any rubbing motion between the web support surface or the web carried thereon and the blade of the knife, the knife should preferably move at substantially said second speed at the point of cutting.

Preferably, the buffer members are rotatable and can roll upon the surface of said support member whilst limiting the approach of said blade thereto.

The knife may cut by pressing towards a flat or smoothly curved region of the web support surface. Alternatively, it may co-operate with a shearing edge on said web support surface and cut with a shearing action.

Thus, said web support member may have at least one transversely running shearing edge which ^\' co-operates with said knife to cut said moving web by a shearing action and typically has a plurality of said shearing edges spaced circumferentially around the surface thereof.

To co-ordinate the correct positioning of the moving knife and the moving shearing edge on the web support member, said knife may be urged resiliently forwards in its direction of travel and may be deflected against said resilient urging by means associated with said knife contacting said web support member and thereafter may be resiliently urged against said shearing edge of the web support member. The web may be fed to said support member over a movable web carrier member which is movable between a first position, defining a first path length between said supply and said web separation location, and a second position, defining a second shorter path length between said web supply and said web separation location, said web carrier member being biassed to said first position and being drawn by the web to said second position when the end of the web is accelerated to said second speed.

Preferably, said web is fed to said web support member over a moveable web carrier member, which is movable between a first position defining a first path length between said web supply and said separation location at said web support member, and a second position defining a second, shorter path length between said web supply and said separation location, said web carrier member being cyclically driven for movement between said first and second positions to accelerate the end

portion of said web into said separation location. The web carrier may be driven through said movement in numerous ways, e.g. by an eccentric (such as a crankshaft) via a follower member, (such as a connecting rod). Preferably, the method includes attracting said end portion of the web to said web support surface to retain the said end portion thereon after said end portion is separated from the remainder of the web. This is preferably achieved by the use of vacuum ports in the web support surface connected to a source of suction to draw the end portions of the web on to the web support surface and to hold them there after they have been cut from the web, the attraction between the end portions of the web and the web support surface not being sufficiently strong to prevent slippage of the end portion of the web on the support surface prior to the end portion being severed from the web. Other means of attracting the severed end portions of the web to the web support surface may be employed such as electrostatic attraction or the choice of materials for the surface of the web support member and the moving web which naturally tend to cling to one another.

The severed end portions of the web carried on the web support member may be further processed in the desired manner. In particular, they may be applied at intervals along a second web or one or more thereof may be applied on to each of a succession of lengths of web material cut from a second web or a sequence of other objects. Such a method may comprise periodically separating portions of a moving web from the web as described above and conveying to said support surface said second web or said lengths cut from a second web so as periodically to apply a said separated end portion to said second web or to a said cut length, and fixing said end portions thereto.

Said fixing operation is preferably carried out by heat sealing said separated end portions to said second web or to said cut lengths. The heat sealing may be carried out by heating either or both of the separated end portions and the

material to which they are to be fixed. The heating may be carried out by any known manner. Preferably however, the heating is carried out by directing hot air on to said web-end portions. It is desirable that one does not heat those regions of the web support surface between the web-end portions carried thereon as such heat would be wasted. Preferably therefore, the hot air is directed on to said web- end portions by a hot air heater directed at a zone through which said web support surface passes and mobile shield members are used to block the application of said hot air to portions of said support surface in said zone other than those bearing said web end portions.

For this purpose, the heater may comprise a manifold having an air outlet lying over said web support surface, said air outlet having a multiplicity of air release openings therein, a plurality of said shield members in said manifold, each movable between an air release position and closed position in which closed position each shield member closes off one or more of said release openings against hot air flow, means normally maintaining each said shield member in its closed position, and means for moving each shield member in turn to its open position to allow hot air flow through the respective air release opening or openings on to a said end portion carried on said web support member in synchrony with the movement thereof.

In a particularly preferred use of the invention, end portions are separated from a first web and are fixed on to a second web, the second web being a web of carton forming material which is subsequently folded, sealed, filled and cut to form filled packages in each of which a respective end portion of the first web is located in and protruding from a seal closing the package from which it can be pulled manually by a user to open the package by breaking the seal in which it is located. The invention includes apparatus for use in separating end portions of a moving web from the web and transporting

said end portions away at a speed which is greater than the speed of the web, comprising means for mounting a supply of said web, means for supplying said web from said supply at a first speed, a web support member having a web support surface, and means for driving said web support member so as to move said web support surface at a second speed which is greater than said first speed, means for guiding the free end of said web to a web separation location at said web support surface including means defining a path of variable length between said web supply and said web separation location, such that varying said path length allows the said end of the web to be accelerated to said second speed without increasing said web supply speed, means for periodically causing acceleration of said end of the web to about said second speed accompanied by said path length variation and means for periodically separating an end portion of said web from the remainder of said web at said web separation location whilst said end portion is moving at about said second speed to allow said separated end portion to be transported on said web support member.

Preferably, the web support member is rotated and said surface thereof is radially outwardly directed.

The means for causing acceleration of said end of the web may comprise a web-pressing member, means mounting said web- pressing member for movement into and out of engagement with said web on said support surface of said web support member and means for driving movement of said web-pressing member so as periodically to press said web pressing member against said web. Preferably, said means mounting said web-pressing member comprises a beam or bridge member and a pair of rotatable members, said beam member at each of a pair of spaced locations therealong being eccentrically pivotally connected to a respective rotatable member whereby synchronised rotation or movement of said rotational members produces a similar

rotary movement at each point along said beam member, said web-pressing member being connected to said beam member.

The web-pressing member preferably comprises a foot mounted on the beam member. The foot may be resilient and/ or may be resiliently mounted.

In particular, the web-pressing member preferably comprises a foot resiliently mounted with respect to said beam member to allow deflection thereof towards said beam member by said web support surface when said foot is brought into engagement with said web on said surface.

The apparatus preferably further comprises a knife also carried on said beam member adjacent said web pressing member.

More generally, said means for periodically separating an end portion from said web from the remainder of said web preferably comprises a knife mounted and driven to execute a parallel motion about a closed curved path substantially tangential to the path followed by the web support surface and in the opposite sense thereto. Preferably, it further comprises a beam member and a pair of rotatable members, said knife being mounted on said beam member and said beam member at each of a pair of spaced locations therealong being eccentrically pivotally connected to a respective rotatable member, whereby synchronised rotational movement of said rotatable members produces a similar rotary motion at each point along said beam member.

Said web support surface may include at least one shearing edge extending transversely thereof for in use co¬ operating with said knife to cut said web by a shearing action and said knife preferably comprising a blade and a pair of cam follower members positioned with said blade extending between them. Said web support surface may have cam surfaces adjacent said shearing edge for engagement with said cam follower members, means being provided resiliently urging said blade forward in its direction of rotation, against which urging means said blade is deflected opposite to its direction of rotation by said cam follower members co-operating with said

cam surfaces and by which said blade is subsequently urged forward to shear and slide against said shearing edge.

Said cam follower members preferably comprise rollers mounted for rotation about an axis transverse to the direction of movement of said web support member.

For press-cutting (without shearing) the knife preferably comprises a blade mounted on a blade carrier to extend longitudinally thereof and a pair of buffer members mounted longitudinally spaced along said blade carrier with said blade between them, said buffer members establishing a datum level for said blade when the knife is in a cutting position with respect to said web support surface.

Preferably, the buffer members are each a roller rotatable with respect to the blade carrier about an axis transverse to the direction of movement of said web support member.

Preferably, the said means for guiding the free end of the web to the said web support member comprises a roller adjacent said web support member and means for driving said roller to feed said web on to said web support member.

Means is preferably provided to form a nip with said roller for feeding said web on to said web support member, said web passing in use through said nip.

The means for defining said variable length path may comprise a movable web carrier member which is disposed in a path for said web between said web supply means and said web support member, means mounting said web carrier member for movement between a first position in which it defines a first length for said web path and a second position in which said web carrier member defines a second shorter length for said web path, and means biassing said web carrier member to said first position.

The means for guiding the free end of the web on the one hand and said web carrier member may both preferably be constituted by the same member. Thus, for this purpose the driven roller for feeding the web may be arranged on a movable

support which is movable to carry the roller between said first and second positions to vary the path length between the web separation station and the web supply. The path length between the roller and the web supply can remain constant through said motion, e.g. if the roller is on an arm which is pivoted about an axis through which the web path passes.

In its second aspect, the invention includes apparatus for applying lengths separated from a first web at intervals along a second web or on to a succession of lengths of web material cut from a second web, which comprises means mounting a supply of said web, means for supplying said web from said supply at a first speed, a web support member having a web support surface, and means for moving said web support surface at a second speed which is greater than said first speed, means for guiding the free end of said web to said a web separation location at web support surface including means defining a path of variable length between said web supply and said web separation location, such that varying said path length allow the said end of the web to be accelerated to said second speed without increasing said web supply speed, means for periodically causing acceleration of said end of the web to said second speed accompanied by said path length variation and means at said web separation location for periodically separating an end portion of said web from the remainder of said web whilst said end portion is moving at said second speed to allow said separated end portion to be transported on said web support member, and means for conveying to said support surface said second web or said cut lengths to contact said support so that in use said first web portions are transported to said second web or said cut lengths and applied thereto by said support member.

Such apparatus preferably further comprises heat sealing means for fixing said web portions to said second web or cut lengths thereof. The heat sealing means preferably comprises a hot air heater directed towards a portion of said web support surface,

at least one mobile shield member, and means driving the or each mobile shield member for movement such that in use the or each shield member obstructs the flow of hot air from said heater except to allow said hot air flow to a respective region of said support surface at which is being transported a first web portion.

To this end the heater may comprise a manifold having an inlet for air, optionally means within the heater for heating the air, and an air outlet disposed opposite a portion of the surface of said web support member, said outlet having a multiplicity of air release openings therein, a multiplicity of said shield members in said manifold, each shield member being movable between an air release position and closed position in which closed position each said shield member closes off one or more of said air release openings against hot air flow, means normally maintaining each said shield member in its closed position, and means for moving each shield member in turn to its open position to allow hot air flow through the respective air release opening or openings in synchrony with the said web support member.

The means for moving each shield member in turn may comprise cam means associated with the web support member for rotation therewith and cam follower means associated with each shield member for moving the respective shield member to the open position responsive to said cam means.

Several aspects of the invention will be described and illustrated with reference to the preferred embodiments thereof illustrated in the accompanying drawings in which:-

Figure 1 is a schematic overall elevation of an embodiment of apparatus according to the invention;

Figure 2 is an enlargement of the web end portion separating station in Figure 1;

Figure 3 is a plan view of the apparatus of Figure 1;

Figure 4 is a longitudinal cross-section on the line A-A of Figure 5 of the knife assembly of the apparatus of Figure 1;

Figure 5 is a transverse cross-section on the line B-B of Figure 4;

Figure 6 is a cross-section parallel to the plane of Figure 1 through a part of the heater nozzle of the apparatus of Figure 1;

Figure 7 is a cross-section on the line C-C of Figure 6;

Figure 8 is a perspective view of an alternative form of cutting station from that used in the apparatus of Figures 1 to 7; Figure 9 is an elevation view of the face of the knife of Figure 8 with part of the web support member shown in section;

Figure 10 is an enlarged sectional view of the line X-X of Figure 9; Figure 11 is a side elevation of an alternative mechanism for feeding the web to the web separation station;

Figure 11a shows the circled part of Figure 11 on a larger scale; and

Figure 12 is front elevation corresponding to Figure 11. As shown in Figure 1, apparatus according to the invention may include a source of supply for a web 10 of carton forming material such as laminated paper board, feeding paper board to a die cut roller 12 which runs against a cylindrical web support member 14 described in detail hereafter. The paper board web passes over the surface of the web support member 14 to a nip between the web support member 14 and a further roller 16 over which it is withdrawn from the apparatus.

A web of plastics film 18 is drawn from a supply by a pair of feed rollers 20, 20\' and passed to a web cutting station 22 described in detail hereafter which is located adjacent the web support member 14. Short lengths 24 are cut from the end of the web 18 of plastics film at the cutting station 22 and are carried on the web support member through the zone of operation of a hot air heater 26 and are

eventually brought into contact with the paper board web 10 at spaced intervals therealong and heat sealed thereto.

In greater detail, the mechanism for cutting short lengths from the end of the plastics film web 18 will now be described with reference to Figures 2 to 5.

Referring to Figure 2, the cutting station 22 comprises a knife assembly 28 carried on a pair of beam members 30. The knife assembly will be described in detail with reference to Figures 4 and 5 below. However, in brief the knife assembly includes an elongate blade mounted to a support and as can be seen in Figure 3, the support extends between and runs transversely with respect to the beam members 30. Each beam member 30 has a pattern of cut-out holes and slots such that the beam member can operate as a stiff spring allowing a degree of deflection along the plane of the blade of the knife.

Each beam member 30 is mounted in a similar manner. In each case at each end of the beam member 30 there is provided a pulley 32 rotatable on a shaft which also carries a rotatable member 36 to be driven by the pulley about the same axis. The beam member 30 is pivotally mounted to the rotatable member 36 about an axis 34 spaced from the axis of rotation of the pulley. The rotatable member 36 is mushroom shaped and the "head" of the mushroom shape provides a counterweight for the motion of the beam member and its attached knife assembly, the beam member 30 being pivotally mounted to the mushroom shaped rotatable member 36 at the end of the "stalk" of the mushroom.

Each of the pulleys 32 is driven for rotation by a belt 38 driven by a motor 40.

The motion executed by the beam member can therefore be seen to be a parallel motion, each point on the beam executing a synchronised circular motion.

The plastics film web is fed via the pair of feed rollers 20, 20\' one of which is driven by a belt 42 and passes from the rollers 20, 20\' to a further roller 44 constituting a

movable web carrier member which is provided at the end of a bell crank 46 which is pivotally mounted about a pivot axis 48 and which has a first arm 50 and a second arm 52 extending initially at right angles to one another. The arm 50 is towards its free end curved away from the arm 52 and carries the roller 44 at its end. A curved plate 54 is carried on the arm 50 in such a manner as to provide a guidance slot for the plastics film web between the curved plate 54 and the adjacent part of the arm 50. The roller 44 runs against the curved plate 54 and is driven by belts 56 and 58. The bell crank 46 is biassed towards the position shown in the figure by a coil spring 60 attached to the second arm 52. The end of the second arm 52 also carries a cam follower roller 62 which is positioned to interact with a cam 64 provided to rotate with the pulley 32 at the right hand end of the beam member 30.

A cylindrical stop member 66 is provided which limits pivoting movement of the bell crank in a clockwise sense.

The knife assembly 28 as shown in Figures 4 and 5 comprises an elongate blade carrier 68 carried towards each end by beam members 30. An elongate blade 70 is adjustably positioned on the blade carrier 68 by a plurality of bolts 72. Cylindrical end portions of the blade carrier 68 outboard of the attachment to the beam members 30 each carry a rotatable buffer member 74 having a hard cylindrical outer surface and supported for rotation on the knife carrier 68 by axially preloaded roller bearings 76 so as to eliminate radial play between the buffer member 74 and the blade carrier 68. The two cylindrical rotatable buffer members 74 define between them a surface of rotation and the blade member 70 is adjusted to lie just within that surface of rotation.

In cross-section as shown in Figure 5, the blade carrier 68 incorporates and L-shaped bracket extension 78, an arm of which extends down parallel to the line of the blade 70. To the free end area of the bracket 78 is mounted a member for periodically preventing slippage between the plastics film web and the rotatable support member 14. This takes the form of

a plate-like member or foot 80 having an end portion which curves round towards the point of application of the blade to form a web pressing member. The web pressing member 80 is mounted adjacent the blade on a pair of leaf springs 82 and its motion upwards parallel to the blade is limited by an elastomeric pad 84.

The web support member 14 has six equi-radially spaced anvil areas 86 at each of which a line of bores 88 extend from the interior of the web support member 14 to its surface as a line of vacuum ports. Interiorly, they are connected to a manifold 90 (Figure 1) which is in-turn connected to a source of vacuum (not shown).

Hot air heater 26 has a nozzle which extends around approximately 170" of the circumference of the web support member 14 and has an inlet pipe 87 for the supply of hot air and an arcuate outlet nozzle the underside of which facing the surface of the web support member 14 takes the form of a perforated plate 89 (Figure 7). Within the nozzle above the perforated plate 89 there is provided a row of perforation blanking plate members 91\' each of which extends across the width of the nozzle in the direction of the axis of rotation of the web support member 14. Each blanking plate 91 is carried at each end by a U-shaped bracket 92 which is turn is mounted to a rod 94 extending out through the side of the nozzle of the heater 26 through an elongate hole. The escape of air through the said hole is prevented by a blanking washer 96 held against the side of the nozzle by a coil spring.

A cam follower 98 is attached to each rod 94 and is mounted for motion radial of the web support member 14 against the biassing of a coil spring 100. It can be seen that lifting of the cam follower members 98 at each end of a particular blanking plate 91 will lift the blanking plate 91 from the perforated plate 89 at the base of the heater nozzle thereby opening those perforations which were underlying the plate.

The web support member 14 is provided with cam follower members (not shown) which are positioned at each end of each of the anvil portions 86 in such as way each bear upon the cam follower members 98 of the nozzle of the heater 26. The operation of the apparatus as described above is as follows:-

Plastics film is withdrawn from its web supply by feed rollers 20, 20\' and is fed toward the roller 44 from where it is fed on by the rotation of the roller 44 so as to pass on to the surface of the web support member 14 immediately up¬ stream of the location of the knife blade 70. At this stage the bell crank 46 is held away from the knife blade 70 by the spring 60.

The web support member 14 is continuously rotated, anvil portions 86 thereof passing in succession through the cutting station 22.

In the cutting station 22, rotation of the pulleys 32 carries the knife assembly through a circular motion essentially tangential to the web support member 14. This is synchronised to the motion of the web support member 14 such that the knife blade 70 makes it closest approach to the web support member as an anvil portion 86 thereof passes through the cutting station.

As the knife assembly in its circular motion approaches the web support member 14 a short length of the web of plastics film 18 will have been fed over the surface of the web support member and through the cutting station. It should be appreciated that the rotational speed of the surface of the web support member is substantially greater than the rate of feed of the plastics web 18. As the knife assembly approaches the web support member, the web pressing member 80 contacts the web 18 and presses it against the surface of the web support member. Up to this point, the web support member has been slipping underneath the web 18 but pressure of the web pressing member holding the web against the web support member 14 prevents the continuation of this slippage and the web 18

at this point now seeks to advance at the rate of motion of the web support member 14. It is temporarily able to do this without pulling further web off the supply by drawing the roller 44 at the free end of the bell crank 46 in toward the cutting station 22 against the force of the spring 60 and until the first arm 50 of the bell crank 46 reaches the stop 66. Immediately prior to this occurring, the knife blade 70 is brought into contact with the web through the rotary motion of the knife assembly on its beam 30- and makes a partial thickness cut through the web. The buffer members 74 are brought into contact with the web support member 14 at this point in the operation. They of course come down on to the web support member 14 on either side of the width of the web 18 and do not contact the web itself. The point of the knife blade 70 lies within the circle of rotation defined by the buffer members 74 so that the blade remains spaced by a predetermined extent from the anvil surface 86 of the web support member 14 and therefore cuts partially only through the thickness of the web 18. Generally, the web 18 will be a multilayer plastics film in which there is a relatively strong layer provided to give mechanical strength to the film and at least one heat sealable plastics layer which will be mechanically weak in comparison and which is positioned at the bottom of the web immediately on the surface of the web support member. There may well be further layers. It is arranged that the knife cuts through all or substantially all of the mechanically strong layers but none or only a partial amount of the weaker heat sealing layer. The cut is completed immediately before the arm 50 reaches the stop 66 at which point continued rapid rotation of the web support member 14 snatches the portion of the web 18 held by the web pressing member 80 off the end of the web 18 along the cut line, tearing through the thin remainder of the mechanically weak heat sealing layer not cut by the blade 70. The blade assembly is driven such that the tip of the blade 70 moves at substantially the same circumferential speed

as the surface of the web support member so that there is no slippage between them as the cut is made.

Whilst desirably the buffer members 74 just touch the surface of the web support member, any failure in adjustment of those which protrudes them too far in the direction of the web support member surface is of no substantial consequence as the beam 30 carrying the misaligned buffer 74 can deflect to allow both buffer members 74 to come down on to the web support surface. The knife blade 70 is held safely away from the web support surface by its fixed disposition relative to the buffer members 74, so avoiding blunting of the blade by direct contact with the anvil area 86.

The separated end portions of the web 24 are held on the web support surface by the application of vacuum through the bores 88 and are carried under the zone of operation of the heater 26. As each separated end portion 24 passes under the nozzle of the heater 26, the blanking plates 91 immediately above it are momentarily lifted to allow hot air to escape from the nozzle directly on to the separated end portion 24 of the web being carried at that part of the web support surface. Immediately after the web portion 24 has passed any particular blanking plate 91, it is lowered back down to shut off further air flow from that part of the nozzle. By this means, air is directed from the nozzle only on to those portions of the web support surface 14 which are carrying the plastics film to be heated.

Simultaneously with the operation described above, paper board is supplied to the die cut roller 12 on which a pattern of fold and crease lines is impressed on the web prior to it coming into the nip between the die cut roller 12 and the web support surface 14 where periodically a previously heated end portion 24 of the plastics film web is pressed against the paper board web and heat sealed to the plastics coating thereof. The web bearing the heat sealed plastics film strips is then withdrawn from the apparatus and subsequently formed into packages in a known manner such that the plastics film

strips come to lie within a seal in the wall of the container with a portion of the plastics strip available for a user to grasp and pull so as to break open the seal in which it is located. A modification of the cutting station shown in the preceding figures is illustrated in Figures 8 to 10. In this modified form of cutting station, the plastics film web is cut by a shearing action rather than by pressure of a knife blade against a smoothly curved support surface. Apart from the matters described below, the apparatus as a whole is as described with reference to the earlier figures.

The apparatus of Figure 8 includes a web support member

118 having a generally cylindrical surface divided into a broad central strip flanked on either side by portions which are shaped as described below. The portions flanking the central strip are symmetrical. That nearer to the viewer in Figure 8 can be seen to comprise a series of recesses 113 all of similar nature. Each recess 113 has a floor 115 concentric with the outer surface of the web support member but recessed radially inwards. An abutment face 117 connects the floor 115 to the outer surface of the web support member. Starting from the web support member and as best seen in Figure 10, the abutment surface 117 is divided into a first portion 118 which slopes downwardly from the web support surface against the direction of rotation of the web support surface and connects to a second portion 119 which forms an undercut by sloping downwardly in the direction of rotation.

Concentric with floor 115, there is a ledge 120 at a higher level inboard from the floor 115. Ledge 120 therefore lies concentric with the surface of the support member but spaced somewhat below it. The abutment 117 lies in each case generally at the point of cut in the cutting operation but an abutment face 123 at the end of ledge 120 defines a datum for the positioning of the knife. The degree of alignment between faces 117 and 123 depends on the extent if any to which the rollers project in front of the knife blade. This may be by

a greater (as in Figure 8) or a lesser (as in Figure 10) amount.

The central strip of the web support member has at each cutting location a shearing edge 185 forming a step in the surface connected to the next similar shearing edge 185 by a gradually rising ramp portion of the web support surface. At its outer ends, each shearing edge 185 connects with the imaginary line along which the outer surface of the web support member would meet the abutment face 119 if both were projected to meet.

The knife assembly comprises a pair of support mounts 121, only one of which is shown the other being omitted for clarity. Each support mount 121 is carried on a respective beam member 30 which is mounted generally as shown in Figure 2. It is preferred that the beam members 30 for use in the cutting station illustrated in Figure 8 are not cut away to render them more springy but are relatively rigid.

A knife blade 170 is mounted in a blade carrier 168. Blade carrier 168 has at each end a circular bore through which passes a shaft 171 to which the blade carrier 168 is made fast. Shaft 171 is received at each end in linear bearings 173 through which it is slidable in the support mount 121 within limits imposed by a pair of stop members 175 positioned at each end of the support mount 121. The blade carrier is biassed forwardly in the direction of rotation by a coil spring 179 positioned around the shaft 171 in each support mount 121.

The blade carrier 168 as best seen in Figure 9 has at each end a downwardly projecting arm 181 which at its outer end carries a freely rotatable cam follower roller 174 and at its inner end is formed with a shoulder 183 forming a step. The spacing between the steps 183 at each end of the blade carrier matches the spacing between the ledges 120 on opposite ends of the web support member whilst the spacing between the rollers 174 matches the spacings between the recesses 113 of the web support member.

A sprung foot 180 is provided as in the arrangements shown in the embodiment of Figure 1.

In use, the knife assembly including the knife carrier and support mount is carried in a parallel circular motion on the beams 30 in synchrony with the movement of the web support member. The strip of plastics film web is fed over the guide roller 44 as previously described and is trapped upon the surface of the web support member by the sprung foot 180 as the blade assembly moves down towards the web support member. The knife assembly rollers 174 come down on to the surface of the web support member on the sloping faces of the first portions 118 of the abutment face 117, the knife blade being held off the shearing edge 185 on the web support member and the blade and blade carrier 170, 168 being deflected back against the action of the springs 171. As soon as the web support member has rotated far enough to carry the shearing edge 185 into the ideal position, the rollers 174 slip off the slope face 118 of the abutment face 117 and pass on to the undercut second portion 119 of the abutment face 117 allowing the knife blade 170 to be pushed forward by the springs 171 against the shearing edge 185 to make a shearing cut of the plastics web. To guide the knife blade into and through the shearing action when the rollers 174 pass on to the second portion 119 of the abutment face 117, the faces of shoulders 183 are pressed against the rearward facing (in the direction of rotation) faces of the web support member at the ends of the ledges 120. As a guard against blade misadjustment causing the blade to contact the surface of the web support member below and behind (in the direction of rotation) the shearing edge 185, the ledge 120 acts as a stop for the shoulders 183 on the arms 181 of the blade carrier 168.

The severed strip of plastics film 24 is released by the raising sprung foot 180 and carried away on the surface of the web support member 118. The knife blade 170 can have a self-sharpening action with the shearing edge 185 of the web support member.

In the mechanism described above, the web of plastics sealing strip is able to accelerate to the speed of the web support member 14 by the pivoting action of the bell crank 46. This pivoting is not mechanically driven but is a passive response to tension applied through the plastics web itself when the end of the web is pinned against the moving surface of the web support member 14 by the web pressing member 80. In the alternative web feeding mechanism illustrated in Figures 11 and 12, the web pressing member 80 is omitted and the plastics sealing strip web is driven into position to be cut at the appropriate time.

The apparatus illustrated in Figure 11 as before comprises a web support member 14 rotating passed a cutting station 22 which in this case includes a cylinder 268 carrying three knife blades 270 spaced at equal angles from one another. The web support member 14 has at corresponding circumferential spacing around its periphery of plurality of hardened anvil areas against which the knife blades 270 may cut. A pair of arms 246 extend parallel to one another and generally at a tangent to the nip between web support member 14 and cylinder 268. With two further pairs of supporting arms 202 and 204, they form a parallel linkage, each being articulated at one end to an end of an arm 204 and in about their centres to an end of a respective arm 202. Each of the arms 202 and 204 is at its opposite end pivoted to a fixed support. A driven roller 244 is rotatably mounted on between arms 246 so that its axis of rotation coincides with the pivot axis of the connection between arms 202 and arm 246. A further roller 245 is mounted adjacent roller 244 forming a nip therewith. A toothed belt 258 drives roller 244. A connecting rod 290 is pivoted at one end to a rod 291 bridging between the ends of arms 246 and at its opposite end to the crank of a crankshaft 292 which is driven for rotation in synchrony with roller 244 and the knife bearing cylinder 268 as well as the web support member 14. A guide plate 254

extends between the ends of the arms 246 which protrude toward the cutting station 22.

The web 18 is led from a reel, along the line of the arms 202 to the roller 244, through its nip with roller 245 and down the guide plate 254 into the cutting station. It is advanced at a constant rate by rotation of the roller 244 such that a desired length of web will have been passed by the roller 244 to be cut off as a strip by each of the knives 270 in turn. So that, at the moment of cut, the web 18 in the cutting station 22 is moving in the same direction as and at the same speed as the knife 270 and the anvil on the web support member 14, the crank 290 drives the parallel linkage formed by arms 202, 204 and 246 forward so that at the instant of cut the connecting rod 290 is making its maximum forward speed. The parallel linkage moves back and forward again in time for the next cutting operation and as that occurs, further web 18 is fed by the roller 244 to be cut off as a strip in the next cutting operation. The cut strips are captured by vacuum ports (not shown) formed in the surface of web support member 14.

Movement of the arms 246 carrying roller 244 varies the path length between the web supply and the point of web cutting via roller 244 but not the path length between roller 244 and the supply, so that the movement of the arms 246 does not require any variation in unreeling speed.

Many modifications and variations of the invention as described above with reference to the specific embodiment are possible within the scope of the invention.