GB1564397A

GB1564397A - Apparatus for sealing tubular packaging material

Info

Publication number: GB1564397A
Application number: GB2949875A
Authority: GB
Original assignee: Banks C H
Current assignee: Banks C H
Priority date: 1976-10-12
Filing date: 1976-10-12
Publication date: 1980-04-10

Description

(54) APPARATUS FOR SEALING TUBULAR PACKAGING MATERIAL (71) I, CLAYTON HATTON BANKS, a British Subject, of Witham-on-the-Hill, Near Bourne, Lincolnshire, England, do hereby declare the invention, for which I pray that a patent may be granted to me, and the method by which it is to be performed, to be particularly described in and by the following statement : This invention relates to devices for automatically sealing articles such as fruit and vegetables into tubular packaging material.

Commodities such as fruit and vegetables are frequently sold by retailers pre-packed into tubular packaging material. This material is generally in the form of netting, but sheet plastics and other materials are sometimes used.

In the packing operation in the case where netting material is employed, the commodity is generally delivered in batches from a counting or filling machine through a delivery tube on which a compressed length of the tubular netting is stored, sufficient net to enclose the commodity hanging below the mouth of the delivery tube. The batch of the commodity drops from the mouth of the delivery tube into the already-sealed end of the netting material, and a length of netting material between the end containing the commodity and the end of the delivery tube is gathered into a rope. On forming the rope, the netting is pulled tightly over the goods to form a bag, and the rope is then introduced into the anvil aperture of a mechanical clipsealing head at a point as close as possible to the bag.As the rope is introduced into the sealing aperture, the sealing head is operated to apply two spaced metal clip seals around the rope, and the rope then severed between the metal clips. In this way, one of the clips seals the end of the bag in which the commodity is contained, and the other seals the free end of the remaining stored net ready to receive the next batch of fruit or vegetables.

If required, the machine may simultaneously apply a label or tag to the bag and some machines are adapted to apply print markings to this label.

The severed bag containing the commodity drops onto a conveyor belt for removal to a packing station.

The forming of the bag around the articles, and the introduction of the rope of netting material into the clip-sealing aperture of the sealing head, is generally carried out by hand, and although machines are available for performing this operation automatically, the majority of these machines are cumbersome and expensive.

The present invention provides a fully automatic machine for sealing articles into tubular packing material which is simple in construction and relatively inexpensive to manufacture and operate. It overcomes the disadvantages of known machines by providing apparatus in which the sealing head is itself moved into contact with the length of tubular material to perform the sealing operation, additional movement of the sealing head being used if desired to tension and dispense the packaging material.

According to the present invention, there is provided apparatus for automatically sealing articles into a length of tubular packaging material which contains the articles in an already-closed end thereof, comprising a mobile sealing head having a sealing aperture therein for receiving the tubular packaging material in gathered form, drive means for moving the sealing head into the path of the tubular packaging material, gathering means adapted to gather the tubular material into a neck as the sealing head moves into the path of the material to enable the material to pass into the sealing aperture, means for displacing the tubular packaging material relative to the sealing head to draw the articles in the closed end thereof towards the sealing head, and sealing means disposed in the sealing head adapted to apply at least one seal to the gathered neck of material in the sealing aperture.

Conveniently the gathering means are movable with the sealing head and suitably comprise guiding surfaces associated with the sealing head.

The device preferably includes a downwardly-directed delivery tube down which the articles to be sealed into the packaging material are delivered. The tubular material is suitably stored over this tube (for example in concertina fashion), and the articles pass from the end of this tube into the alreadysealed end of the packaging material. The device is constructed such that the sealing head moves into contact with the length of material at a point between the end of the delivery tube and the sealed end of the material in which the articles are contained.

The means for displacing the tubular packaging material relative to the sealing head preferably comprise the drive means for the sealing head which are adapted to continue movement of the sealing head after packaging material has passed into the aperture so as to draw the articles in the closed end towards the sealing head, preferably so that the end of the material in which the articles are contained is drawn tightly up against the sealing head.

At this point, the sealing means in the sealing head are suitably operated to apply the seal to the neck (or "rope") of material therein. Preferably the sealing head is adapted to apply two spaced seals to the rope therein, and the sealing head may also include cutting means adapted to sever the rope between the spaced seals. It is not however essential that two spaced seals are provided on the rope or that the rope is severed between the seals. For example, a chain of interconnected bags containing individual articles or batches of articles may be required, in which case only a single seal would be required between adjacent bags.

In addition, where the packaging material is a plastics material and a heat-sealing head is employed, a single seal of substantial width may be applied to the rope of material, the rope then being cut in the centre of the seal to provide top and bottom seals respectively for adjacent bags.

Where the tubular material is stored over the delivery tube, the sealing head is suitably movable beyond the point at which the articles in the sealed end of the material are drawn up against the head so that a length of material sufficient to enclose the following batch of commodities is dispensed from the delivery tube. In this case, the sealing and cutting means are operated subsequent to this dispensing action.

The delivery tube may be of any suitable shape in cross-section, such as square or semi-circular, but is preferably cylindrical.

Where the material is stored in concertina fashion on the tube, it may be retained by friction only, but if normal friction is insufficient to prevent tubular packaging material being drawn off by the weight of the articles as they drop into the sealed end of the material, means may be provided to increase this frictional force.

As stated, the sealing and cutting means in the sealing head are preferably adapted to operate when the clipping head has moved through a sufficient distance to dispense a predetermined amount of material from the tube. Further movement of the sealing head may however be utilised in order to cause the tail-end of the stored length of tubular material which remains in the head after the sealing and severing operation are completed to be pulled out of the aperture in the sealing head.

The drive means for the sealing head may be operable to reciprocate the sealing head along a path, which may be e.g. arcuate, immediately below the delivery point, the sealing head being arranged to receive the vertical length of packaging material close to the beginning of its movement and to seal and sever the rope at or near the end of its movement.

In one embodiment of the invention, the sealing head is arranged with the sealing aperture in its front face so that the aperture approaches the rope of packaging material in a substantially vertical plane. In an alternative embodiment, the sealing head is arranged so that the sealing aperture approaches the rope of material with its longitudinal axis aligned in a substantially horizontal plane.

Suitably the return movement of the sealing head is timed to take place before the following batch of articles is delivered from the delivery point, - and where reciprocating movement of the sealing head is employed, gate means may be provided operable to prevent a batch of articles from falling into the path of the return movement of the clipping head. In addition, sensing means may be provided operable to sense the arrival of a batch of articles at the delivery point and to initiate movement of the sealing head from its initial position at the appropriate time.

The sensing means and the gate means may advantageously be adapted for location either inside the delivery tube or immediately below the delivery tube, and in one embodiment of the invention a single element constitutes both sensing and gate means.

In another embodiment, the gate means are fixed to the sealing head or the support for the sealing head, and may for example comprise a roll of flexible material one end of which is wound onto a spring-driven roller and the other end of which is secured to the sealing head. The spring-driven roller is mounted on the machine frame, and when the sealing head is moved towards the path of the packaging material, the roll of flexible material unwinds from the roller to provide a supporting surface for articles falling from the delivery point. On return movement of the sealing head, the spring driven roller winds the flexible material back onto the roller surface in the manner of a roller blind.

In an alternative embodiment, this roller blind arrangement is replaced by a simple plate or tray fixed to the sealing head.

Although gathering means separate from the sealing head may be utilised to assist in the introduction of rope into the sealing aperture, preferably the gathering means comprise one or more V-shaped guiding surfaces located on the sealing head, the apex of each guiding surface being located at the entrance to the aperture in the sealing head.

These guiding surfaces may comprise the outer surfaces of the head itself or may be formed for example by a pair of V-shaped guiding elements fixed to that face of the sealing head in which the aperture is formed.

In the case where the aperture is formed in the upper surface of the sealing head, one end of the sealing head may be raised with respect to the other so that the upper surface of the sealing head lies in a plane subtending an acute angle to the vertical plane of movement of the sealing head.

In another embodiment of the invention, instead of being reciprocated about an arcuate path, the sealing head is movable around a closed path and returns along a different part of the path to that followed during its outward movement. This eliminates the problem of articles falling into the path of the sealing head during its return movement, and may be accomplished for example by rotating the sealing head in a substantially horizontal plane about a vertical axis, the sealing head following a circular path with the sealing aperture disposed in a vertical plane adapted to gather a vertically-suspended length of material.

In an alternative and preferred construction, the sealing head is movable in a substantially vertical plane, with its return path located beneath its outward path. In this embodiment, the apparatus suitably comprises a pair of spaced, parallel and vertically disposed side plates, the opposite faces of which are provided with identical guide tracks. The sealing head is located between the side plates and is adapted to follow the guide tracks to describe its closed path of movement The shape of the path defined by the guide tracks can be generally rectangular, generally triangular, or circular, although a combination of these shapes has been found to be most suitable.The end of the delivery tube is advantageously positioned so that the articles are delivered into roughly the centre of the closed path, with the packaging material crossing the path at the point where it will be engaged by the sealing head.

It has been found preferable to locate a table in the centre of the closed path onto which the articles can fall from the delivery tube, the front of this table being situated only a short distance below the mouth of the delivery tube. This table may be downwardly tilted so that articles falling into it run down the tray until they are held by the length of material still joined to the stored length of the tube.This has the effect that the length of material between the articles in the sealed end and the end of the delivery tube is given a slight tension and can be maintained at an angle fairly close to the horizontal; if this length of material is then arranged to intersect the path of the sealing head at a point at which the sealing head is moving substantially vertically upwardly, optimum conditions for gathering the material and guiding the rope thus formed into the sealing aperture can be obtained.

The sealing head may be any suitable sealing head adapted for sealing the type of packaging material to be used but is preferably a clip-sealing head having an anvil and jaws located in the head and adapted to apply metal clip seals around the rope therein.

Cutting means for cutting the rope between the spaced clips are advantageously located inside the clip sealing head. Such a clipsealing head is particularly advantageous when the material used for packing is netting or tubular plastics material.

In the preferred form of the invention, the sealing head is a clip-sealing head and incorporates gathering means in the form of deep V-shaped guiding surfaces formed on the front face of the head, the apex of the guiding surfaces being located at the entrance to the clip-sealing aperture.

If the packaging material is thermoplastic, for example sheet plastics or plastics netting, the sealing head may instead operate on the heat or high frequency welding principle.

Other suitable means for sealing the rope in the sealing head include twist-tying with wire, sealing with adhesive tape or a solvent adhesive, and sewing.

The invention also includes a method of automatically sealing articles into one end of a length of tubular packaging material, comprising the steps of causing articles to be delivered into the already-closed end of a length of the tubular packaging material, moving a sealing head having a sealing aperture therein adapted to receive the packaging material in compressed form into the path of the material, gathering the material into a neck and guiding the neck of material into the sealing aperture, displacing the tubular packaging material relative to the sealing head to draw the articles in the closed end thereof towards the sealing head, and applying at least one seal to the neck of material in the sealing aperture.

Suitably, the articles are delivered into the sealed end of the material at a delivery station and the sealing head is moved into contact with the material at a point intermediate the delivery station and the closed end of the material in which the articles are contained. Preferably, the tubular material is placed under tension by the weight of the articles in the closed end thereof prior to being engaged by the sealing head.

Advantageously, the sealing head is moved around a closed path which interesects the path of material at a point between the deli very station and the closed end of the material in which the articles are contained.

In order that the invention may be more fully understood, embodiments in accordance therewith will now be described, by way of example only, with reference to the accompanying drawings, in which: Fig. 1 shows a side elevation of one embodiment of machine for automatically sealing tubular packaging material, its se quence of operation being shown in broken and chain-dotted lines; Fig. 2 shows a perspective view of the sealing head of the machine shown in Fig. 1; Fig. 3 shows an end elevation of another embodiment of machine for automatically sealing tubular packaging material; Fig. 4 shows a perspective view of another embodiment of machine for automatically sealing tubular packaging material;; Fig. 5 shows a side elevation of the machine shown in Fig. 4 with some parts omitted for clarity and with part of its sequence of operation shown in chain dotted lines; Fig. 6 shows a front elevation of the sealing head of the machine shown in Fig. 4; Fig. 7 shows a front elevation of the operating mechanism of the sealing head shown in Fig. 6, with parts omitted for clarity; and Fig. 8 shows a perspective view of the anvil and hammer assembly of the sealing head shown in Fig. 6.

Referring to the -drawings, Fig. 1 shows a fully automatic machine generally indicated at 15 for clip-sealing tubular netting material 10 which is stored in compressed concertina fashion on a cylindrical delivery tube 11.

The articles to be packed in the netting material, which in this case are oranges 12, are delivered from a counting or weighing machine in batches down the delivery tube 11 and fall into the already-sealed end 13 of the netting 10, to hang below the mouth 14 of the delivery tube 11, as shown in Fig. 1.

The machine 15 is located immediately below the delivery tube 11 and comprises a base 17 to which is secured a trunnion 18; a main machine arm 19 is rotatably mounted at 20 to this trunnion 18.

A piston rod 24 of a pneumatic cylinder 25 is pivotally secured to the main machine arm 19 at 26, and the cylinder 25 is in turn pivotally mounted at 27 to the machine base 17. An outward stroke of the piston rod 24 is arranged to move the main machine arm 19 from the initial position shown in un broken lines in Fig. 1 to the position shown in chain-dotted lines. The return stroke of the piston returns the main machine arm from this latter position to the initial position as shown.

A clip-sealing head 30 is mounted on the upper end of the main machine arm to extend at right angles thereto, as shown in Fig. 2.

It is of conventional construction, being provided with a vertically disposed sealing aperture 31 adapted to receive the netting material in the form of a rope; the sealing aperture has a V-shaped entrance 32 intended to assist in the passage of the rope into the aperture. Internally, the clip-sealing head is provided with an anvil and jaws which are adapted to secure a pair of spaced wire clips around rope in the aperture 31; in addition, cutting means are provided in the head adapted to sever the rope between the spaced clips.

The wire 34 from which the clips are formed is drawn from a pair of reels (one shown, 35) rotatably mounted on the main machine arm 19; if the sealing head 30 is required to secure price tags or the like to the sealed bags, these are drawn from a similaar reel.

The sealing and cutting operations performed by the sealing head 30 are actuated by a pneumatic cylinder and piston assembly 37 mounted on the rear face of the sealing head 30, the piston rod 38 of the assembly being attached to the operating rod of the sealing head by means of a linkage 39.

Gathering means in the form of a pair of V-shaped guiding elements 40 and 41 are mounted on the front face of the sealing head 30 with the apex of each element located at the entrance to the sealing aperture. As will be described, these guiding elements gather the packaging material into a rope to enable it to be introduced into the aperture 31.

As will be apparent from Fig. 1, the location of the sealing head 30 at the upper end of the main machine arm 19 results in the sealing head being reciprocated about an arc of a circle during an outward and return stroke of the piston in cylinder 25. This circle has a centre at point 20, and on an outward stroke of the piston rod 24, the sealing head is moved from initial position A, through points B, C, and D lying along the arc, to final position E. A return stroke of the piston rod 24 moves the sealing head back toposition A.

The sequence of operation of the machine shown in Figs. 1 and 2 will now be described, beginning with the machine and its associated supply of netting material and articles in the condition shown in unbroken lines in Fig. 1.

The oranges to be packed are delivered in a batch from the delivery tube 11 and are suspended below the tube in the end portion of the continuous length of netting 10 which has been previously sealed by a metal clip seal 44. In this condition, the operation of the machine commences by activation of the pneumatic cylinder 25 from a central control box. The main machine arm begins its forward movement, and as the clipping head is moved from position A into the path of the netting at position B, the gathering elements move over the netting, engaging and compressing the material towards their apex.

As the sealing head 30 moves through the path of the material, the material is collected into a rope by the gathering means, and further movement of the head between positions B and C, pulls the rope into the V-shaped entrance 32 the sealing aperture 31, and thence into the aperture itself.

The introduction of the material into the aperture is assisted by the angle of approach to the sealing head towards the suspended length of netting material which, as will be seen from Fig. 1 lies at an acute angle to the vertical axis of the suspended netting.

When the rope of material is fully introduced into the sealing aperture 31, which occurs at a point between position B and position C, a spring-loaded catch inside the sealing head may slip into place; this catch allows a rope of material to pass into the aperture 31 via its entrance slot 32, but prevents rope being withdrawn from the aperture in this direction.

On introduction of the rope into the aperture, the sealing head 30 continues to move between positions B and C, and this further movement draws the pack of netting material 45 upwardly, towards the base of the sealing head 30: when the sealing head reaches position C on its arcuate path, the pack 45 is drawn tightly up against the base of the head.

This position is shown in broken lines in Fig. 1.

It is important that the pack 45 is pulled tightly up against the head so that a tight pack for the articles is formed, and if heavy articles are being packed, it may be necessary to increase the friction retaining the netting material on the tube 11. This is done by providing a braking element which increases this frictional force; such a braking element may for example take the form of a brushlike member mounted over the delivery tube and provided with bristles which act on the packaging material as it is drawn off the tube.

When the sealing head reaches position C, upward movement of the pack 45 is no longer possible, and further movement of the sealing head 30 draws material off the delivery tube where it is stored in concertina fashion. This dispensing of material from the delivery tube takes place between positions C and D.

When the sealing head reaches position D, the piston 37 is actuated to operate the cutting and severing operations to the rope in the aperture 31; two spaced seals are placed on the rope, and the rope severed between these seals; the pack 45, which is now provided with upper and lower clip seals 46 and 44 respectively, falls from the sealing head onto a conveyor belt 48 for removal.

After clipping and cutting operations are completed at point D, the sealing head 30 continues to move forward from point D to point E; this is done in order to ensure that the tail end 49 of the packaging material with its new seal 50 is pulled clear of the sealing aperture 32.

It will be appreciated that the amount of material dispensed from the tube during movement of the sealing head from point C to point D is determined by the stroke of the cylinder 25 and the point at which the clipping piston 37 operates. As both of these values may be pre-set, a predetermined length of material sufficient to form the next package with the required additional length, may be dispensed.

When the clipping head reaches point E, shown in chain-dotted lines in Fig. 1, the cylinder 25 immediately begins its return stroke, and the sealing head and the machine arm are returned to their initial position A.

Due to the simple reciprocating nature of the machine, very rapid operation may be obtained, and generally the arm 19 is returned to its initial position A before the next batch of oranges is delivered into the end of the sealed netting. The machine shown in the drawings has the ability to seal at least 30 packs per minute.

In order that the machine may work in timed relation to the supply of articles, the operation of the cylinder 25 may if required be activated either by the counting machine which is delivering articles in batches down the delivery tube 11, or alternatively by a sensing device which senses the arrival of a batch of articles. Such a sensing device is shown at 511 mounted in the tube 11, but it may be mounted in any other suitable position such as immediately below the mouth 14 of the tube.

In addition, if delivery of the batches of articles down the tube 11 is very rapid, it may be necessary to provide a gate for preventing articles from falling into the path of the sealing head during its return movement to initial position A. Such a gate may be located in a similar position to the sensing device 511, and one single element may in fact perform both sensing and gating functions.

Such sensing and gating devices may be operated penumatically in circuit with the cylinders 25 and 37.

Fig. 3 illustrates a modified version of the machine shown in Figs. 1 and 2.

The machine, generally indicated at 50, is illustrated in end elevation, in the position equivalent to a view looking from the left in Fig. 1.

In this embodiment, all the main operating parts of the machine, such as main machine arm 19, cylinders 25 and 37, and sealing head 30 are substantially the same as those of the machine of Figs. 1 and 2, and accordingly the same references are used to designate these parts. In addition, the arcuate path of movement of the sealing head 30, and the points A, B, C, D and E of operation of the various machine functions, are also substantially the same.

In this embodiment, the sealing head 30 is mounted on the main machine arm 19 with the entrance 32 to the sealing aperture 31 on the upper face 51 of the sealing head 30 rather than on the front face as in the machine of Figs. 1 and 2. Further, the free end 52 of the machine arm 19 is bent away from the vertical axis of the arm, the sealing head 30 being secured to this free end by bolts 54.

As a result, the sealing head 30 is located on the arm with its free end 55 raised above the end 56 secured to the arm, the upper face 51 lying in a plane which subtends an acute angle with the vertical plane in which the sealing head moves.

In this embodiment, the gathering means for gathering the length of material 10 into a rope is constituted by a pair of guiding elements (one shown 58) and the portion 59 of the upper face 51 of the sealing head. The plane surface of the portion 59, and the surface 60 of the elements 58, together form V-shaped guiding surfaces which have an apex located at the entrance to the sealing aperture. These surfaces gather the packaging material into a rope as the sealing head moves into the path of the material, to enable the rope to be introduced into the sealing aperture 31.

As the sealing aperture in this embodiment is on the upper face of the sealing head and the head lies at an angle of the vertical, when the rope of material 10 is contacted by the head, the force on the rope is directed through the sealing aperture itself, with the result that the rope passes into the aperture more easily than in the arrangement of Figs. 1 and 2.

In addition, the horizontally disposed sealing aperture ensures that the rope has no tendency to be pulled out of the aperture by the weight of the commodity towards the end of the path of movement of the sealing head.

Instead, the weight of the packed bag acts to retain the rope in the correct position in the sealing aperture until the severing operation is carried out.

A number of modifications may be made to the machines shown in Figs. 1 to 3 to improve or vary their operating characteristics. For example, although the frictional retaining means for retaining the netting on the tube has been discussed in relation to the packaging of heavy articles, such frictional retaining means may also be used in a different way where very light or easily damaged articles such as tomatoes or sprouts are being packed. In this case, it is important that excess force is not applied to the articles in the bag as the bag is tightened, and to avoid this the netting material may be made a loose sliding fit on the tube 11.In order to prevent the loose netting being pulled off the tube when it is not required to be dispensed (e.g. when the articles fall into the end of the sealed material), frictional retaining means may be employed adapted to retain and release the netting at appropriate times during the packing cycle. For example, these means may be adapted to release the netting immediately the formed bag is pulled up against the sealing head.

Where light articles which are not easily damaged are being packed, for example sprouts, it may be desirable to artificially increase the weight of the pack by providing a static or movable bar or roller which engages the material between the sealing head and the delivery tube. Alternatively, this may be done by a spring-loaded bar or roller which engages the material at a point below or at the same level as the sealing head.

The embodiments of the invention shown in Figs. 1 to 3 both have the disadvantage that the delivery of articles from the delivery tube must be timed to avoid the articles falling into the path of the sealing head during its return stroke. This disadvantage is eliminated by the construction of machine shown in Figs. 4 to 8, in which the sealing head moves around a closed path with the return part of the path located below the outward part.

Referring to Figs. 4 to 6, the machine comprises a pair of parallel, vertical side plates 71 and 72 maintained in spaced relation by frame members 73 and 74. The side plates are each formed with matching continuous slots 75 and 76 respectively which form guide tracks defining a closed path of movement of a clip-sealing head 80.

The overall shape of the closed path can be seen clearly in Fig. 5, the path being generally triangular with its rounded apex located at the front of the machine.

The clip-sealing head 80 is located between the side plates 71 and 72 and engages the slots 75 and 76 by means of co-axial rollers 81 and 82 which are freely rotatable about axles mounted on opposite end faces of the head. These rollers engage the upper and lower faces of the slots and accuarately guide the clip-sealing head around its path of movement between the side plates.

The machine is provided with fixed end plates 85 and 86 spaced from the corresponding side plates 71 and 72 by spacer blocks 87.

Between each pair of side and end plates 71 and 85, and 72 and 86, are rotatably journalled toothed wheels 89, 90 and 91 (Fig. 5).

The axes of these toothed wheels are located at the centres of the circular arcs which are followed by the slots 75 and 76 at a change in direction of the path, i.e. at each corner of the path. A drive chain 93, extends around each set of toothed wheels and thus follows exactly the path of its adjacent slot. The drive chains are connected to the axles of the rollers 81 and 82 by means of connecting blocks 96 (one shown in Fig. 4) and thus provide means by which the clip-sealing head may be driven around its closed path. An electric motor (not shown) is connected by a belt or chain drive to the axle of a pair of corresponding toothed wheels in the side and end plates to provide motive power for the chain drives, which, when the machine is in operation, move the clip-sealing head 80 continuously around its guide tracks 75 and 76 in the direction of the arrows in Figs. 4 and 5.

The co-axial rollers 81 and 82 provide a pivotal axis for the clip-sealing head in the slots 75 and 76, and in order to maintain the head at the desired angle of inclination during its movement around the closed path, a guide bar 99 is mounted for pivotal movement in a vertical plane about an axis 100. The guide bar is located close to the side plate 72 and is slidably received in a bearing located inside the clip-sealing head 80. The clip-sealing head is free to slide along the length of this guide bar, which acts to maintain the clipsealing head radially inclined to the pivotal axis 100 at all times.

The guide bar 99 forms part of a sensing mechanism for the clip-sealing head and is provided with a slot 102 close ot its free end.

This slot is engageable by the wheel of a spring-loaded microswitch 103 which follows the outer surface of the bar as the clip-sealing head moves along it. The operation of this sensing mechanism will be described hereinafter.

The delivery tube 105 for the articles to be packed is similar to that described in connection with Figs. 1 to 3, and the netting material 106 is again stored on this tube in concertina fashion. In this embodiment, the brake means for preventing excessive lengths of material being dispensed comprises a collar 108 of resilient material such as foam rubber which is caused to grip the netting on the tube by a clamp 109. The force exerted by this clamp on the resilient collar (and thereby the amount of tension required to dispense material from the tube) is adjustable by means of a bolt 110. The clamp 109 also serves to mount the delivery tube on a support arm 112 fixed between the end plates 85 and 86.

A receiving tray 114 is located between the side plates and inside the closed path followed by the clip-sealing head. This tray receives articles falling from the end of the delivery tube 105 into the closed end of the netting material and, as may be seen in Fig. 5, is tilted downwardly towards the front of the machine. If desired, sensing means may be associated with this tray, so that operation of the machine is initiated when articles are received by the tray from the delivery tube.

The basic sealing and cutting operations performed by this machine are the same as those described in connection with the machines shown in Figs. 1 to 3, but the movement and disposition of the main machine parts is somewhat different.

As before, the articles, in this case onions 116, fall from the end of the delivery tube into the sealed end 117 of the neting material, but in this case the articles are supported on the receiving tray 114 in the centre of the closed path of movement of the clip-sealing head. The artilces roll down this tray until they are restrained by the length of netting material 118 which has previously been dispensed from the tube 105.

Further movement of the articles down the tray is prevented by the tension in the netting material, the weight of the articles being insufficient to draw further netting material past the collar 108.

The length of netting material 118 is thereby maintained at an angle which is fairly close to the horizontal, the path of this material crossing the closed path of the clipsealing head at approximately its uppermost post (see Fig. 5). As will also be seen in Fig. 5, it is at this point that the clip-sealing head 80 moves into contact with the length of material 118.

The clip-sealing head 80 is provided with gathering means in the form of deep, Vshaped guiding surfaces 120 which have an apex at the entrance to the sealing aperture 121. These guiding surfaces can be seen clearly from Fig. 7.

The upward movement of the clip-sealing head 120 from the position of Fig. 5 engages and gathers the material 118 into a rope which is then guided into the sealing aperture by further movement of the head. As the rope passes into the sealing aperture, a springloaded catch 122 moves into position to prevent removal of the rope prior to the severing operation.

Movement of the clip-sealing head along the upper part of its path initially causes the articles 116 to be drawn up against the underside of the sealing head (as shown in Fig. 4), further movement beyond this point dispensing the required length of additional material from the delivery tube for forming the next bag. The position of the sealing head shown in chain-dotted lines in Fig. 4 is the position immediately prior to the sealing and cutting point. The sealing and cutting operations of the clip-sealing head are actuated when the wheel of the microswitch 103 passes into the groove 102; the sealing point is thereby determined by the position of this slot along the length of the guide rod 99.

On sealing and cutting the formed bag from the length of netting material, the free end of the material is pulled out of the sealing aperture by further movement of the head, which returns along the lowermost portion of its closed path ready to receive the next length of material. The sealed bag falls from the base of the head for removal by conveyor means.

It will be noted that the return movement of the clip-sealing head takes place below the point at which batches of articles are delivered to the machine. The return path of movement of the clip-sealing head cannot therefore be obstructed by articles being delivered to the machine, and the machine does not have to "wait" for the return stroke of the clip-sealing head. This continuous movement of the sealing head around a closed path gives a considerable speed advantage over the machines of Figs. 1 to 3.

As shown in broken lines in Fig. 5, a labelling device 124 may be provided working in timed relation with the clip-sealing head to offer printed labels to the sealing head as it follows its return path. The labels are collected one at a time by a spring clip 125 mounted on the underside of the clip-sealing head 80, and include string tags which are blown into the clipping aperture by an air jet for incorporation into the sealed end of each bag. The labelling device suitably prints these labels before they are offered to the sealing head.

The operating mechanism of the clipsealing head 80 is shown in detail in Figs. 7 and 8. In Fig. 7, one half of the outer casing of the head has been removed, the remaining part being indicated at 140. The two halves of the casing are normally held together by screws 141 (Fig. 6) which engage in tapped bores 142.

The operating mechanism of the sealing head is located between a pair of spaced, parallel base plates 143, mounted in the casing by means of screws 144. The outer-most base plate is also omitted from Fig. 7 for clarity.

The main constituents of the clip-sealing mechanism comprise an anvil assembly, which includes a pair of spaced anvils (one shown, 145) between which is located a cutting blade 147, and a hammer 146.

The anvil assembly is mounted on a rod journalled between the base plates, the cutting blade being pivotal about the rod whereas the anvils are fixed firmly to it. The hammer 146 is journalled between the base plates for rotation about an axis 148, and is reciprocable about this axis by means of a pneumatic piston and cylinder assembly 150, which includes a piston rod 151 pivotally connected to the hammer at 152. An inward stroke of the piston rod pulls the hammer into striking engagement with the anvils 145; an outward stroke of the piston rod returns the hammer to the position shown in Fig. 7.

When the sensing machanism associated with the clip-sealing head indicates that a sealing and severing operation is to be performed, the piston and cylinder assembly is operated to complete a single inward and a single outward stroke of the hammer.

A return stroke of the hammer operates a ratchet roller-drive comprising a double pair of serrated nip rollers (one pair shown 154 and 155), each pair of rollers constituting drive means for a wire strip, the strips being fed from twin co-axial reels (not shown 157).

The twin lengths of wire from the reels 157 each pass between their corresponding pair of nip rollers and are fed upwardly through a slot formed between wire guides 159 and 160 into the path of the hammer 146.

These wire portions (the length of which is determined by the length of the return stroke of the hammer) comprise the elements from which the clip seals are formed.

The striking face 161 of the hammer is formed with a cutting edge 162 which, in conjunction with an edge 163 formed on the wire guide 159, severs the projecting lengths of wire 158 from the remainder of the strip.

These lengths of wire are immediately trapped between the striking face of the hammer and a pair of retractable pins (one shown 164). These pins each have a bearing face 165 which engages in a groove 166 formed in one face of the hammer. This groove 166 co-operates with the bearing face 165 to jam its corresponding pin in position between the end plates. As forward movement of the hammer continues, the individual wire lengths are bent around these pins into open-ended loops, and immediately the loops are formed, the bearing faces 165 of these pins pass into an aperture 168 which forms a continuation of the grooves 166.

This causes the pins to pivot about axes 169 in the end plates and retracts the pins from the path of the hammer; this enables the openended loops to be pushed over the rope of netting material present in the aperture 121.

Each anvil 145 is provided with a die surface 170 which, with the opposing die surface 161 of the hammer, is intended to form the wire into a B-shaped clip around the netting material. Such a clip is shown at 173 in Fig. 8 around the rail-end 174 of a finished bag.

In order to ensure that the free ends of the wire loops pass cleanly into the die surfaces 170, each die 145 is provided with upper and lower locating ears 175 and 176, slidably engageable in corresponding slots 177 and 178 formed in the striking face 161 of the hammer 146. These ears have leading edges which have surfaces forming a continuation of the die surfaces 170 of the anvils 145 and ensure that no jamming of the wire occurs as the free ends are brought into contact with the anvils.

The impact of the hammer on the anvils crushes the wire clips tightly around the rope of netting material, and during the final phase of movement of the impact stroke, the leading edge of the hammer engages an edge portion 181 of the cutting blade, which pivots about its axis and severs the rope of netting material between the spaced seals.

The hammer is then returned to its starting position shown in Fig. 7 by the outward stroke of the piston rod ready for the next sealing operation.

Considerable variations in the construction of these embodiments are possible. For example, providing sufficient lateral support can be given, a single side plate and guide track may be utilised, with the sealing head travelling for example on rollers over the vertical face of the side plate. In another variation, the tracks, the rollers and the side plates may be dispensed with entirely, the sealing head being supported and driven by the chain drives alone, with the run of the chains themselves determining the path of movement of the sealing head. In another embodiment, endless belts (which may be cogged) are substituted for the chain 93.

Alternatively, a crank arm may be used to carry the sealing head in place of the chains and guide tracks. Such a crank arm may be used to move the sealing head in a substantially vertical plane (as for example shown in the embodiment of Figs. 4 to 8), or in an alternative arrangement the sealing head may be moved in a substantially horizontal plane on such an arm, e.g. it may be rotated in a horizontal plane.

In an alternative to the collar and clamp arrangement 108. 109, for retaining the netting over the delivery tube, the frictional force is generated by an inflatable annular diaphragm which encircles the delivery tube and which is hermetically sealed to the front and rear faces of an annular supporting ring surrounding the tube. A radial bore is formed in the supporting ring for the introduction of pressurised air, and when the diaphragm is inflated it expands inwardly and traps the packaging material against the delivery tube. This arrangement is particularly advantageous, as by adjusting the air pressure inside the diaphragm, the frictional force acting on the material can be varied.

Although all the machines described are operated by pneumatics and require only a simple pressurised air supply, the machinery may clearly be operated electrically using solenoids or electric motors and microswitches, instead of pneumatic cylinders and sensing elements. In addition, while the packaging material used in the machines described is netting, any suitable material in tubular form may be used such as sheet plastics material, fabric material or micromesh netting. Further, the clip-sealing head may be replaced by for example a heatsealing head suitable for plastics material, but any suitable tying, sewing or sealing device may be used.

While the embodiments of the machines are described and shown in the drawings as packing fruit or vegetables, it will be appreciated that virtually any material may be packed utilising a machine constructed in accordance with the invention. Such materials may be in powder, particulate or granular form, and may take the form of other piece goods such as tennis balls, or machine components.

It will be appreciated that the apparatus and method of the invention can be used for packing articles individually as well as in batches, and the references in the specification and claims to "articles" should be construed accordingly.

WHAT I CLAIM IS: 1. Apparatus for automatically sealing articles into a length of tubular packaging material which contains the articles in an already-closed end thereof, comprising a mobile sealing head having a sealing aperture therein for receiving the tubular packaging material in gathered form, drive means for moving the sealing head into the path of the tubular packaging material, gathering means adapted to gather the tubular material into a neck as the sealing head moves into the path of the material to enable the material to pass into the sealing aperture, means for displacing the tubular packaging material relative to the sealing head to draw the articles in the closed end thereof towards the sealing head, and sealing means disposed in the sealing head adapted to apply at least one seal to the gathered neck of material in the sealing aperture.

2. Apparatus as claimed in Claim 1, wherein the gathering means are movable with the sealing head and comprise guiding surfaces associated therewith.

3. Apparatus as claimed in Claim 2, wherein the sealing aperture is provided with an entrance slot, and said gathering means comprise one or more V-shaped guiding surfaces located on the sealing head, the apex of the or each guiding surface being disposed at said entrance slot.

4. Apparatus as claimed in any of Claims 1 to 3, further comprising means for separating the sealed package thus formed from the remainder of the tubular packaging material so as to leave a closed end thereon in readiness for the next packaging operation.

5. Apparatus as claimed in Claim 4,

**WARNING** end of DESC field may overlap start of CLMS **.

Claims

**WARNING** start of CLMS field may overlap end of DESC **. die surfaces 170 of the anvils 145 and ensure that no jamming of the wire occurs as the free ends are brought into contact with the anvils. The impact of the hammer on the anvils crushes the wire clips tightly around the rope of netting material, and during the final phase of movement of the impact stroke, the leading edge of the hammer engages an edge portion 181 of the cutting blade, which pivots about its axis and severs the rope of netting material between the spaced seals. The hammer is then returned to its starting position shown in Fig. 7 by the outward stroke of the piston rod ready for the next sealing operation. Considerable variations in the construction of these embodiments are possible. For example, providing sufficient lateral support can be given, a single side plate and guide track may be utilised, with the sealing head travelling for example on rollers over the vertical face of the side plate. In another variation, the tracks, the rollers and the side plates may be dispensed with entirely, the sealing head being supported and driven by the chain drives alone, with the run of the chains themselves determining the path of movement of the sealing head. In another embodiment, endless belts (which may be cogged) are substituted for the chain 93. Alternatively, a crank arm may be used to carry the sealing head in place of the chains and guide tracks. Such a crank arm may be used to move the sealing head in a substantially vertical plane (as for example shown in the embodiment of Figs. 4 to 8), or in an alternative arrangement the sealing head may be moved in a substantially horizontal plane on such an arm, e.g. it may be rotated in a horizontal plane. In an alternative to the collar and clamp arrangement 108. 109, for retaining the netting over the delivery tube, the frictional force is generated by an inflatable annular diaphragm which encircles the delivery tube and which is hermetically sealed to the front and rear faces of an annular supporting ring surrounding the tube. A radial bore is formed in the supporting ring for the introduction of pressurised air, and when the diaphragm is inflated it expands inwardly and traps the packaging material against the delivery tube. This arrangement is particularly advantageous, as by adjusting the air pressure inside the diaphragm, the frictional force acting on the material can be varied. Although all the machines described are operated by pneumatics and require only a simple pressurised air supply, the machinery may clearly be operated electrically using solenoids or electric motors and microswitches, instead of pneumatic cylinders and sensing elements. In addition, while the packaging material used in the machines described is netting, any suitable material in tubular form may be used such as sheet plastics material, fabric material or micromesh netting. Further, the clip-sealing head may be replaced by for example a heatsealing head suitable for plastics material, but any suitable tying, sewing or sealing device may be used. While the embodiments of the machines are described and shown in the drawings as packing fruit or vegetables, it will be appreciated that virtually any material may be packed utilising a machine constructed in accordance with the invention. Such materials may be in powder, particulate or granular form, and may take the form of other piece goods such as tennis balls, or machine components. It will be appreciated that the apparatus and method of the invention can be used for packing articles individually as well as in batches, and the references in the specification and claims to "articles" should be construed accordingly. WHAT I CLAIM IS:

1. Apparatus for automatically sealing articles into a length of tubular packaging material which contains the articles in an already-closed end thereof, comprising a mobile sealing head having a sealing aperture therein for receiving the tubular packaging material in gathered form, drive means for moving the sealing head into the path of the tubular packaging material, gathering means adapted to gather the tubular material into a neck as the sealing head moves into the path of the material to enable the material to pass into the sealing aperture, means for displacing the tubular packaging material relative to the sealing head to draw the articles in the closed end thereof towards the sealing head, and sealing means disposed in the sealing head adapted to apply at least one seal to the gathered neck of material in the sealing aperture.

5. Apparatus as claimed in Claim 4,

wherein the sealing head is adapted to apply two spaced seals to the gathered neck of material in the sealing aperture, and said means for separating the sealed package are adapted to sever the neck between the spaced seals.

6. Apparatus as claimed in any of Claims 1 to 5, wherein the means for displacing the tubular packaging material relative to the sealing head comprise the drive means for the sealing head which are adapted to continue movement of the sealing head after the packaging material has passed into the aperture so as to draw the articles in the closed end thereof towards the sealing head.

7. Apparatus as claimed in Claim 6, further comprising an article delivery station at which the tubular packaging material is stored, wherein the sealing head is movable into the path of the tubular packaging material at a point intermediate the delivery station and the closed end containing the articles.

8. Apparatus as claimed in Claim 7, wherein the drive means for the sealing head are adapted to continue movement of the sealing head beyond the point at which the articles in the sealed end of the material are drawn up aginast the sealing head so as to dispense a length of material from the delivery station sufficient to enclose a following batch of articles.

9. Apparatus as claimed in Claim 7 or Claim 8, wherein the article delivery station comprises a downwardly-directed delivery tube through which the articles to be sealed into the package material are delivered.

10. Apparatus as claimed in Claim 9, wherein the delivery tube is located above the path of movement of the sealing head, and in operation the length of material intermediate the delivery tube and the articles which is engaged by the sealing head is tensioned by the weight of articles in the sealed end thereof.

11. Apparatus as claimed in Claim 9 or Claim 10, wherein the delivery tube is cylindrical, and in operation the packaging material is retained over the tube and stored in concertina fashion thereon.

12. Apparatus as claimed in Claim 11, wherein means are provided to increase the frictional force retaining the stored tubular packaging material on the delivery tube.

13. Apparatus as claimed in claim 12, wherein said means comprises an inflatable annular diaphragm which encircles the delivery tube and which on inflation is adapted to grip the packaging material between the diaphragm and the outer surface of the delivery tube.

14. Apparatus as claimed in any of the preceding claims, wherein the sealing aperture is provided with an entrance slot located in the front face of the sealing head, and the sealing head is adapted to engage the packaging material with the slot aligned in a substantially vertical plane.

15. Apparatus as claimed in any of Claims 1 to 13, wherein the sealing aperture is provided with an entrance slot located in the upper face of the sealing head, and the sealing head is adapted to engage the packaging material with the longitudinal axis of the slot aligned in a substantially horizontal plane.

16. Apparatus as claimed in any of the preceding claims, wherein the sealing head is mounted for movement along a linear path, and the drive means for the sealing head are operable to reciprocate the sealing head along said linear path.

17. Apparatus as claimed in any of Claims 1 to 15, wherein the sealing head is mounted for movement along an arcuate path, and the drive means for the sealing head are operable to reciprocate the sealing head along said arcuate path.

18. Apparatus as claimed in Claim 17, wherein the sealing head is operable to engage the packaging material close to the beginning of its outward movement along said arcuate path, and to apply said at least one seal at or near the end of its outward movement.

19. Apparatus as claimed in Claim 17 or Claim 18, wherein the sealing head is mounted on one end of an arm which is pivotally mounted at its other end, and the drive means are operable to reciprocate the arm about said pivot.

20. Apparatus as claimed in any of Claims 1 to 15, wherein the drive means for the sealing head are operable to carry the sealing head around a closed path.

21. Apparatus as claimed in Claim 20, wherein said closed path is disposed in a substantially horizontal plane.

22. Apparatus as claimed in Claim 21, wherein said closed path has at least some substantially vertical components, and the return part of the path is located beneath the outward part of the path.

23. Apparatus as claimed in Claim 22, wherein the sealing head is located within the space defined by a pair of spaced support members, and the drive means for the sealing head comprise an endless chain drive associated with each support member and adapted to carry the sealing head around its c.osed path of movement.

24. Qpparatus as claimed in Claim 23, wherein the support members comprise a pair of vertically disposed supporting plates, and the chain drives are carried by sprocket wheels journalled in said plates.

25. Apparatus as claimed in Claim 24, wherein guide means are provided for guiding said sealing head around said closed path, comprising side plates arranged inwardly of said chain drives and said supporting plates, which side plates are formed with continuous slots defining said path, and rollers pivotally mounted on said sealing head adapted to engage said continuous slots.

26. Apparatus as claimed in any of Claims 23 to 25, wherein a guide rod is mounted between said spaced support means for pivotal movement in a vertical plane, and the sealing head is adapted to slidably engage said guide rod.

27. Apparatus as claimed in Claim 26, wherein said guide rod is provided with abutment means operable to actuate sensing means on the sealing head as the sealing head moves along said guide rod.

28. Apparatus as claimed in any of Claims 23 to 27, wherein article support means are provided in the centre of said closed path for supporting articles in the end of the tubular packaging material, and said support means are adapted to allow said articles to move downwardly thereon to tension the length of packaging material prior to engagement by the sealing head.

29. Apparatus as claimed in Claim 29, wherein said article support means comprises a downwardly tilted receiving tray.

30. Apparatus as claimed in any of the preceding claims, wherein she sealing head comprises a clip-sealing head having an anvil aperture and jaws located therein adapted to apply a pair of spaced metal clip seals around a neck of packaging material within said sealing aperture, and cutting means adapted to sever the neck of material between the spaced clips.

31. Apparatus as claimed in Claim 30, wherein the clip-sealing head comprises an anvil assembly and a hammer located respectively on opposite sides of the sealing aperture, said hammer being pivotally mounted within the sealing head and being reciprocable about its pivotal axis by hammer drive means, and a roller drive for feeding twin lengths of wire from reels to said anvil assembly, said roller drive being operated by a ratchet wheel assembly driven by reciprocation of said hammer.

32. Apparatus as claimed in Claim 31, wherein the clip-sealing head is provided with retractable pins located in the path of said hammer which are adapted to form said lengths of wire into open-ended loops to enable said hammer to push the loops over the neck of material in the aperture and to impact the free ends of the loop against die surfaces formed in the anvil assembly.

33. Apparatus as claimed in Claim 32, wherein the striking face of the hammer is formed with die surfaces shaped to co operate with those formed in the anvil assembly, and the impact of the hammer against said anvil assembly is adapted to form wire loops therein into B-shaped clips which tightly enclose the neck of material within the sealing aperture.

34. Apparatus as claimed in Claim 33, wherein the anvil assembly is provided with ear portions which are engageable with complementary slots formed in the hammer over the last portion of striking movement thereof, said ear portions having surfaces forming continuations of the die surfaces of the anvil assembly which ear portions are adapted to guide the free ends of the wire loops into said die surfaces as the hammer makes its impact stroke.

35. Apparatus as claimed in Claim 34, wherein a cutting blade is pivotally mounted between the two sets of die surfaces, and the hammer is operable to engage said cutting blade to sever the neck of material between the spaced clips during the final part of its impact stroke.

36. A method of automatically sealing articles into one end of a length of tubular packaging material, comprising the steps of causing articles to be delivered into the already-closed end of a length of the tubular packaging material, moving a sealing head having a sealing aperture therein adapted to receive the packaging material in compressed form into the path of the material, gathering the material into a neck and guiding the neck of material into the sealing aperture, displacing the tubular packaging material relative to the sealing head to draw the articles in the closed end thereof towards the sealing head, and applying at least one seal to the neck of material in the sealing aperture.

37. A method as claimed in Claim 36, wherein gathering means are provided comprising guiding surfaces movable with the sealing head, and the tubular packaging material is gathered into a neck, and the neck guided into the sealing aperture, by movement of the sealing head relative to the material.

38. A method as claimed in Claim 36 or Claim 37, wherein two spaced seals are applied to the neck of material and the neck is severed between the spaced seals.

39. A method as claimed in any of Claims 36 to 38, wherein the articles are delivered into the closed end of the material at a delivery station and the sealing head is moved into contact with the material at a point intermediate the delivery station and the closed end of the material in which the articles are contained.

40. A method as claimed in Claim 39, wherein the tubular packaging material is displaced relative to the sealing head to draw the articles in the closed end towards the sealing head by additional movement of the sealing head in a direction away from the delivery point.

41. A method as claimed in Claim 40, wherein the sealing head is moved a sufficient additional distance away from the delivery point to draw the package containing the articles against the sealing head.

42. A method as claimed in Claim 41, wherein the tubular material is stored at the delivery station and sufficient length thereof ro enclose the following batch of articles is caused to be dispensed therefrom by further movement of the sealing head after the package has been drawn against the sealing head.

43. A method as claimed in any one of Claims 40 to 42, wherein the tubular material is placed under tension by the weight of the articles in the closed end thereof prior to being engaged by the sealing head.

44. A method as claimed in Claim 43, wherein the sealing head is moved around a closed path which intersects the path of material at a point between the delivery station and the closed end of the material in which the articles are contained.

45. A method of automatically sealing articles into one end of a length of tubular packaging material, substantially as hereinbefore described with reference to Figs. 1 and 2, or Fig. 3, or Figs. 4 to 8 of the accompanying drawings.

46. A device for automatically sealing articles into one end of a length of tubular packaging material, substantially as hereinbefore described with reference to Figs. 1 and 2, or Fig. 3, or Figs. 4 to 8 of the accompanying drawings.