GB2054453A - Processing sheet or web material using jaw means - Google Patents

Abstract

In a machine for processing material in sheet or web form, e.g. a packaging machine, processing tools 18, 28 are movably mounted in jaws 14, 15, which are adapted to move the tool means between active and inactive positions. In active position the tools 18, 28 apply force to the material, and the reaction is provided by stationary buttress means 11, 12, incorporated in the machine, so that the forces in question have no effect, or negligible effect, on the jaws means. The jaws 14,15 may be pivotally movable in relation to said buttress means between the full and broken line positions of Figure 2. The tools may comprise a cutting tool 18 between two elongate heated sealing tools 19 and a compression tool 28 movable by shafts 23, 29, respectively, axially reciprocable by piston rods 26, 32 of cylinder 25, 33. A duct 34 for cooling air or water may be provided in the tool 28. <IMAGE>

Description

SPECIFICATION Improvements in and relating to the processing of material in sheet or web form using jaw means This invention relates to the processing of material in sheet or web form, and more especially to processing such material by applying pressure thereto by jaw means. The invention is applicable, for example, to packaging operations, and may be incorporated in a packaging machine provided with jaw means movable between operative and inoperative positions in relation to the packaging material.

The material in web- or sheet-form may, for example, be paper, plastics or combinations of these materials such as frequently used in the packaging industry for the manufacture of packages of different types, such as boxes, cases and containers. Normally, the conversion of this flat starting material to packages of the desired type takes place in a packaging machine, which often not only produces packages, but fills them with the desired contents. In the machine the packaging material is fed along a processing path where it passes a number of processing stations at which the material is processed in various ways, e.g. the material may be punched, cut, folded or sealed.

A known packaging machine produces nonreturnable packages for liquid contents, e.g. milk, from a web of laminated material which comprises an inner carrier layer of paper, covered on each face with one or more homogeneous layers of thermoplastic material. The originally flat web is converted to individual, filled containers when the web, as it moves substantially vertically downwards through the machine is successively converted to tubular shape by joining together and sealing in a liquidtight manner the opposite longitudinal edges of the web. At the bottom end of the tube movable jaw elements are provided for sealing, shaping (if desired) and cutting off individual containers from the tube.More particularly, the tube is sealed at its bottom end, loaded with contents, e.g. milk, and sealed at equispaced transverse zones which divide the filled tube into a coherent series of liquid-filled containers. This is cut in the said transverse sealing zones whereby the containers are severed from one another so that single containers are produced. The containers may also be subjected (as indicated above) to a shaping operation with the object of imparting to them a particular desired shape, e.g. a parallelpipedic form.

The transverse sealing, the cutting off (as well as the shaping (if desired) are effected by processing jaws which are situated one on each side of the tubular web and which operate in pairs. The processing jaws are moved between active and inactive positions. In the active position the working surfaces of the jaws press against the tube and while flattening it carry out, at the same time, the desired working operation, e.g. the transverse sealing. After the working operation has been carried out, the jaws are moved to inactive positions spaced from the tube so that the latter can be advanced freely between the jaws.Owing to the great difference in space requirement to accommodate the filled tube of a substantially circular cross-section, and the flattened parts of the tube, the movement of the jaws when they are moved from active to inactive positions or vice versa is relatively large. Moreover, since the jaws have to be strong because of the stresses arising when the working surfaces are pressed against the material, they are of substantial size which is a disadvantage since it is endeavoured in general to make the packaging machines as small and compact as possible. The design furthermore makes the suspension and support of the jaws complicated and expensive, since on the one hand they must be capable of the large movement necessary and on the other hand tolerate the forces arising, which in such working operations as sealing and cutting are considerable.

It is thus generally desirable to reduce or eliminate the above-mentioned disadvantages in known machines, and it is an object of the present invention therefore to provide means whereby that requirement can be met.

With this end in view the invention consists in a machine for processing material in sheet or web form comprising tool means by which the material is subjected to substantial pressure, characterised in that the tool means are carried by movable jaw means adapted to move the tool means between active and inactive positions, and wherein, the tool means in active position are actuated by a force which is effectively not transmitted to or through said jaw means or the bearings thereof.

A device in accordance with the invention for processing material in web- or sheet-form, may comprise a processing jaw which is supported so in the foundation or frame of the device that it can be manoeuvred between an inactive position, and an active position in which a working tool carried by the jaw is made to bear against the material, and the working tool is movably connected with the jaw. The forces arising on activation of the working tool may be adapted so that they are transmitted by intermediate elements to the foundation or frame without affecting the support of the jaws.

Preferably the working device is provided with a force-transmission element supported in the jaw, which in the active position of the jaw is adapted to connect the working tool carried in the front part of the jaw with a driving element connected with the foundation. As a result of this the reaction forces arising on activation of the driving element are transmitted directly to the foundation which ensures relief for the jaw, and the support of the jaw.

The transmission element may be an axially displaceable shaft which in the active position of the jaw is directly in front of, and axially in line with, the driving element. The parth of the force from the driving element to the working tool becomes thus completely rectilinear and therefore does not affect the jaw.

The shaft may be firmly connected with the working tool and is adapted to urge the latter, by means of a return spring, to the inactive, retracted position. This design ensures that the working tool is returned to the retracted position when it is not acted upon by the driving element. The driving element may consist of a piston and cylinder unit.

The jaw in its active position may be directly in front of, and in line with, a counterjaw situated on the opposite side of the material. The jaw may be supported pivotably, the axis of rotation being perpendiculartothe longitudinal direction of the material in web- or sheet-form. This orientation of the axis of rotation of the jaw implies that when the jaw is pivoted from the inactive to the active position the working surface of the jaw is moved in the same direction as the material in web- or sheet-form, which makes possible successive abutments of the working surface of the jaws on the material.

The jaw in its active position may bear against the fixed foundation, with fixed transmission elements arranged on the rear part of the jaw. These transmission elements completely absorb the reaction forces to which the jaw is subjected in co-operation with the counter-jaw situated on the opposite side of the material.

The invention will now be described in greater detail with reference to the accompanying schematic drawings which illustrate by way of example a container-shaping process in a packaging machine incorporating the invention.

Figure 1 shows a web of packaging material in a packaging machine in accordance with the invention being converted into successive packaged containers. For the sake of clarity only the details necessary for an understanding of the process have been illustrated.

Figure 2 shows a side view, partly in section, of parts of the preferred embodiment of the invention adapted to be utilized to carry out the process shown in Figure 1: Figure 3 shows a plan view of the arrangement shown in Figure 2.

A method for the conversion of a web of packaging material into individual liquid-filled containers is shown in Figure 1. The arrangement in accordance with the invention is of particular use in packaging machines which manufacture packages in accordance with this method and the invention will be described therefore as designed and used in such a machine. However, it should be understood that this description does not exclude the use of the arrangement in accordance with the invention in other methods or machines where material in web- or sheet-form is processed by working jaws.

In the method illustrated schematically in Figure 1 the web of packaging material 1 is supplied to a machine (not shown) in the form of a roll 2, which is suspended so that it is freely rotatable in the machine. The web is of a laminated type and may comprise an inner carrier layer e.g. of paper or foamed plastics, covered on each face with thermoplastic material, which makes possible the sealing of the material by application of heat and subsequent pressing together, a process known as heat-sealing.

The web may in some cases also contain further layers, e.g. of aluminium foil, but in order to make possible the abovementioned sealing an outer layer of the web must consist of heat-sealable e.g. thermoplastic material.

From the freely rotatable roll 2 the drawn web 1 moves upwards towards a guide roller 3 over which is passes to run substantially downwards through the machine. On its downward path from the guide roller 3 the web 1 is converted to tubular shape by freely rotatable shaping rollers in annular array, bringing the opposite longitudinal edges of the web 1 together so that they finally overlap and are combined to form a longitudinal joint along the tubular web. The sealing of the two web edges overlapping one another is effected by a joining tool 5 located underneath the shaping rollers 4, which tool heats the thermoplastic outer layer(s) of the material in the sealing zones along the web edges, and presses together the edges where the plastics has been heated to softening so that a liquid-tight seal is effected.After the sealing the bottom end of the tube which is transversely sealed to be liquidtight and the tube is filled with the desired contents.

The contents, e.g. milk, are supplied to the tube from a container 6 by a filler pipe 7 which extends into the upper end of the tube, not yet completed or sealed.

With the help of a level-monitoring device (not shown) the supply of contents is controlled so that the level of contents is always kept at a prearranged distance belowthe joining tool 5.

Below the joining tool 5 is located the jaw arrangement in accordance with the invention. The arrangement 8 operates thus on a part of the tube which is below the contents level and is continuously kept filled with contents. The tube is advanced downwards through the jaw assembly by feed elements (not shown) in the form of reciprocating levers provided with suction pads situated above the jaw assembly. The jaw arrangement presses the tube walls together at equi-spaced transverse zones, the walls being sealed to one another in a liquid-tight manner, so that substantially cushion-shaped containers filled with contents are produced.The arrangement in accordance with the invention also severs the containers 9 thus formed, from each other by cutting through the said transverse sealing zones, whereupon the containers are finished and are removed from the machine by a conventional con veyor 10.

After thins schematic description of a method for the manufacture of packaging containers in a machine incorporating the invention, the function and the detailed design of a preferred embodiment of the invention will be described with reference to Figures 2 and 3, which show the jaw arrangement from the side and partially in section (Figure 2) and from the top (Figure 3).

In Figure 2 are shown two parts 11 and 12 of the buttress, foundation or frame of the structure which parts are connected to one another, and to the rest of the structure by a third part 13. The parts 11 and 12 are spaced at some distance from one another and between them runs the partly compressed packaging material tube 1, atthe upper end of which isthe bottom end of the filler pipe 7. Between the two buttress parts 11 and 12 are situated two movable processing jaws 14 and 15, which jaws are pivotably supported by shafts 16 and 17 respectively mounted in the foundation part 13, (Figure 3).The shafts 16 and 17 are connected to driving elements (not shown) in the form of gears, cams or hydraulic driving elements and they rock the sealing jaws 14 and 15 between the working position or active positions shown in full lines in Figures 2 and 3, and the inactive position indicated in Figure 2 by dashdotted lines.

The jaws 14 and 15 comprise working surfaces which in the active position of the jaws are located directly in front of one another, one on each side of the flattened tube 1. The working surfaces of the jaws have a width (transversely of the direction of movement of tube) which exceeds by a little the width of the flattened tube. The working surface of the jaw 14 comprises working tools, namely a centrally situated cutting tool 18 extending over the full width of the jaw, and elongated heating tools 19, stationary one on each side of the tool, in the form of electrical resistance elements also extending over the full width of the jaw. The heating tool 19 is connected by electric conductors 20 to a source of current.The conductors 20 run from the heating tool 19 through the processing jaw 14 through the hollow shaft 16 carrying the jaw, and a current collecting device 21 mounted on the shaft to a source of current installed on the machine, or separately.

The cutting tool 18 is movable in the plane of the jaw in direction towards or away from the compressed tube 1 and is manoeuvred for this purpose by a shaft 23 which is provided with a flange 22 and which can be axially displaced. Round a part of the shaft 23 a helical compression spring 24 is mounted and adapted to urge the shaft 23 axially in a direction away from the tube. In the active position of the jaw 14, as shown, the free end of the shaft 23 bears against the end of a piston rod 26 of a hydraulic piston-and-cylinder unit 25. On the rear part of the jaw, moreover, two fixed transmission elements 27 are provided, which, in the active position of the jaw, bear against the buttress or foundation part 11.

The jaw 15 has a working tool in the form of an elongated compression tool 28, which extends transversely and substantially at right angles to the longitudinal axis of the tube 1 and has a width which somewhat exceeds the width of the flattened tube. In other words, the compression tool 28 has a similar orientation to the cutting tool 18 situated in the opposite jaw, and is similarly manoeuvred by a force transmission element 29 supported to be axially displaceable in the jaw 15. The shaft 29 is provided with a flange 30 and is spring-loaded by a helical compression spring 31 urging it in the direction away from the tube 1. As a result, in the active position of the processing jaw the rear end of the force transmission element 29 bears against the front end of a piston rod 32 which is reciprocally displaceable by a double-acting piston and cylinder unit 33.

The compression tool 28,29 is provided with a duct for cooling medium e.g. air or water, extending through the tool in longitudinal direction. The duct 34 extends through the jaw 15 and at the other end runs out through its shaft 17, and a discharge element 35 arranged on the shaft to terminate at a suitable cooling-medium reservoir.

During operation of the machine and the abovedescribed device in accordance with the invention a web is supplied in known manner, to the machine where, passing successively downwards through the machine, it is converted to tubular shape and filled with contents. By feed elements provided with suction pads mentioned earlier (not shown) the filled tube is moved intermittently downwards towards the device in accordance with the invention, each displacement corresponding to the length of one finished container. During the main part of each displacement the processing jaws 14 and 15 are in their inactive position, that is to say, in the position substantially parallel with the axis of the tube, as indicated by dash-dotted lines in Figure 2.When, during a feed movement, the tube has been advanced downwards by substantially one half of a package length the movement of the processing jaws 14, 15, from the inactive to the active position commences. More particularly, two shaft 16,17 are actuated by driving elements (not shown) to pivot the processing jaws to the active position, wherein the working tools of the processing jaws are positioned directly in front of one another, one on each side of the flattened packaging tube. Since during the pivoting from the inactive to the active position the working surfaces, or the working tools, of the jaws 14, gradually approach one another a successive pressing together of the tube walls takes place during the later part of a feed stroke.This initial pressing together takes place substantially without any sliding between the working surfaces of the jaws 14,15 on the one hand and the outside surface of the tube on the other, since the speed of pivoting of the jaws is adapted to correspond to the speed of feed of the tube.

When the jaws 14 and 15 have reached their active positions, the working tools of the jaws are directly in front of one another, one on each side of the tube, at the same time as the jaws are in line with one another as well as with the piston and cylinder units 25,33. In this position the jaws have already pressed the tube flat so that the contents have been displaced and the inside walls of the tube area between the jaws contact one another.The working tools of the two jaws, that is to say, the cutting tool 18 and the compression tool 28 are retained, during the whole of the process so far described, in their inactive rear position by the two helical compression springs 24,30 ,which, through the force- transmission elements 23, 29 provided with flanges and connected to the cutting tool and the compression tool respectively, urge the working tools to the inactive positions.

When the two jaws 14, 15 are in their active position, in line with one another as well as with the two piston and cylinder units, the sealing of the compressed portion of the tube is initiated. More particularly, the piston and cylinder unit 33 is actuated causing the force transmission element or shaft 29 to move the compression tool 28 to bear against the flattened tube, which is thus pressed against the surface of the counterjaw provided with heating tools. At the same time, or possibly a little earlier, the heating tool 19 is activated so that the tube material pressed between the working tools of the jaws is heated to such atemperaturethatthe thermoplastic outer layers of the material soften.

While the simultaneous strong compression caused by the compression tool 28 induces the inner softened thermoplastic layers of the material resting against one another to be fused together to a liquid-tight seal. The pressure exerted by the compression tool 28 is transmitted through the compressed tube material to the processing jaw 14 and further through the two transmission elements 27 to the buttress foundation part 11,withoutthetwo shafts 16, 17, carrying the processing jaws, being subjected to any stress whatever, since the working tools 18, 28, as well as the force transmission elements 23, 29 are freely displaceable in axial direction in relation to the processing jaws and are merely carried and supported by them.

When the sealing is complete, or during the sealing operation, the piston and cylinder unit 25 is also activated, to urge the cutting tool 18, by the transmission element or the shaft 23, and against the action of the return spring, to bear against the working surface of the compression tool 28. The cutting tool then effects a transverse cut through the median line the sealing zone of the tube so that the cushion-shaped container 9 below the jaws is seal rated from the part of the tube located above the jaws.The compressive force exercised by the cutting tool 18 is transmitted by way of the compression tool 28, and the force transmission element 29, to the piston rod 32 of the piston-and-cylinder unit, so that in this case too the mounting of the processing jaw, (that is to say, the support by the driving shaft) is not affected in any undesirable manner by the force from the piston-and-cylinder unit.

As will be evident from the above description, a device for the processing of material in web- or sheet-form with the help of processing jaws is provided by the invention, in which the movable jaws and their mountings are completely protected or separated from the heavy forces which are required for the proper sealing and cutting of the material. Since the sealing jaws merely serve to perform the initial pressing together of the tube and to carry and control the actual working tools, the jaws and their suspension can be made comparatively light and uncomplicated, which appreciably reduces the cost of the design and not least contributes to make possible a readily accessible system with easily replaceable parts.This is also helped to a large extent by the fact that the two working tools, that is to say, the piston-and-cylinder units, are situated in and are firmly connected to the machine frame, buttress or foundation, without any actual mechanical connection to the processing jaws.

it will also be evident from the description that the term "material of web- or sheet-form" not only means such material in flat form but also in the different stages of development, e.g. tubular shape, cushion shape or more or less finished package shape. Although the arrangement in accordance with the invention has been described as more particularly suitable for the processing oftubular packaging material, the arrangement is also suitable for any other type of web-forming operation when the working tools have to be moved apart to allow the feed of the material.

While the jaws 14, 15 exercise complete control over movement of the working tools 18,28 between their active positions (shown in full in Figures 2 and 3), and their inactive positions (shown in dotted line in Figure 2), the freedom of those tools for limited movement in relation to the jaws ensures that when the tools are operated in active positions (Figure 2) the reaction to the forces applied to the packaging tube are absorbed and reacted by the stationary buttress members 11 and 12, and have no effect, or no appreciable effect on the jaws 14, 15 or their mountings 16, 17.

Claims (16)

1. A machine for processing material in sheet or web form comprising tool means by which the material is subjected to substantial pressure, characterised in that the tool means are carried by movable jaw means adapted to move the tool means between active and inactive positions, and wherein, the tool means in active position are actuated by a force which is effectively not transmitted to or through said jaw means or the bearings thereof.

2. A machine as claimed in Claim 1 wherein the tool means are mounted with a limited degree of freedom of movement in said jaw means.

3. A machine as claimed in Claim 1 or 2 wherein said tool means incorporate a rod or shaft axially reciprocable in said jaw means supporting it.

4. A machine as claimed in any of Claims 1; 2 or 3 wherein said jaw means are pivotally movable between active and inactive tool positions.

5. A machine as claimed in any of Claims 1-4 wherein in active position said tool means extend between said material being processed, and a stationary foundation, frame or buttress adapted to provide reaction forces when said tool means are activated to apply substantial force to the material.

6. Apparatusforthe processing of material in web- or sheet-form comprising a processing jaw (15) which is so supported in the foundation (13) of the apparatus that it can be manoeuvred between an inactive position and an active position, wherein a working tool (28) carried by the jaw is made to bear against the material (1), characterised in that the working tool (28) is movably connected to the jaw (15), the forces arising in the activation of the working tool being adapted so that they are transmitted by intermediate elements (27, 29) to the foundation without affecting the support of the jaw.

7. Apparatus in accordance with Claim 6, characterised in that the working tool (28) is provided with a force transmission element (29) supported in the jaw, which in the active position of the jaw (15) is adapted so that it connects the working tool (28) carried in the front part of the jaw with a driving element (33) connected with the foundation.

8. Apparatus in accordance with Claim 2, characterised in that the force transmission element (29) is an axially displaceable rod or shaft, which in the active position of the jaw is straight in front of, an axially in line with, the driving element (33).

9. Apparatus in accordance with Claim 8, characterised in that the shaft (29) is firmly connected with the working tool (28) and is adapted to urge the latter by means of a return spring (31) to the inactive, retracted, position.

10. Apparatus in accordance with any of Claims 7,8 or 9 characterised in that the driving element (33) consists of a piston-and-cylinder unit.

11. Apparatus in accordance with any preceding claim, characterised in that the jaw (15) in its active position is straight in front of, and in line with, a counterjaw (14) situated on the opposite side of the material (1).

12. Apparatus in accordance with any preceding claim, characterised in that the jaw(s) 14, 15 is/are supported pivotably, the axis of rotation being perpendicular to the longitudinal direction of the material (1) in web- or sheet form.

13. Apparatus in accordance with any preceding claim, characterised in that the jaw (14) in its active position rests on the foundation with fixed force transmission elements (27) arranged on the rear part of the jaw.

14. Apparatus or a machine for processing material in sheet or web form, incorporating jaw and tool means substantially as described herein with reference to the accompanying drawings.

15. A packaging machine incorporating jaw and tool means substantially as described herein with reference to the accompanying drawings.

16. A filled and sealed package whenever produced by a machine substantially as claimed in any preceding claim.