GB2164889A - Cutting system - Google Patents

Abstract

A cutting system comprises a cutting station (10) at which a lay L of material assembled between a cutting die (D) and a cooperating cutting surface (P) can be cut by pressing said die through the lay against the surface, means (20) being provided for advancing the assembly to and through said station (10). Cooperating with the advancing means (20), for forming therewith an enclosed chamber within which said assembly can be contained, is enclosing means (36) comprising a top member (34) and skirt arrangement (38) which extends between the top member and a surface portion of the advancing means and forms a seal therebetween, the skirt arrangement (38) providing side walls of the chamber. Means is also provided for connecting the enclosed chamber to a suction source which is effective to cause the top member (34) to be drawn more closely to the advancing means (20), the skirt arrangement (38) yielding during such movement of the top member and the lay being compressed between the cutting die and the cooperating cutting surface. <IMAGE>

Description

SPECIFICATION Cutting system This invention is concerned with a cutting system comprising a cutting station, at which a lay of material assembled between a cutting die and a cooperating cutting surface can be cut by pressing said die through said lay against said surface, and means for advancing the assembly of the lay, cutting die and cooperating surface to said station.

Such cutting systems operate satisfactorily where it is a question of relatively incompressible material. In the case of highly compressible material, e.g. foam material, on the other hand, the number of layers in a lay is likely to be small in order to enable the lay to be accommodated between the pressing members at the cutting station (e.g. the platens of a cutting press) or, if the lay has a large number of layers, the depth of the lay requires the pressing members to be initially spaced apart by a correspondingly large distance to receive the lay therebetween.In the first case, with a small number of layers, the work handling is inefficient, since especially in the stripping of the cut pieces following the cutting operation, the same amount of time and effort is effectively required in the case of a small or a large number of layers and thus a reduction in the number of layers involves a corresponding increase in stripping time for the same number of cut pieces. In the second case, with a larger depth of lay, the time taken to move the pressing members together is increased proportionately, so that the cutting operation is significantly slowed down with a consequent loss of production time.What is more, in this second case the action of pressing at the cutting station means that the lay is subjected to localised pressure in the region of the blades of the cutting die such that distortions arise in the lay resulting in significant variations in size between cut components from the same lay.

In order to overcome this problem it has been proposed (see e.g. US-A 3598006) to use a vacuum table on which a lay can be assembled, a sheet or panel of substantially air-impervious sheet material, e.g. thin polyethylene, being spread over the work and cooperating with the vacuum table to draw said sheet towards the vacuum table and thus to compact the lay. It will of course be noted that the panel used is expendable since it is cut each time a lay is cut and thus a new sheet has to be provided each time a cutting operation takes place.

It will also be noted that the cutting system described in said US specification does not utilise a cutting die and cooperating cutting surface, but rather utilises a knife of the reciprocating type. On the other hand it has also been proposed to use a sheet of air-impervious sheet material in combination with an assembly of cutting die, lay and cutting surface, and indeed in two different ways, -viz. by assembling a lay on a cutting die, arranged with its blades uppermost, placing the sheet of airimpervious material over the lay and placing a cutting pad on top, or alternatively forming an assembly, again with the cutting die beneath and with blades uppermost, and covering the assembly with a sheet of air-impervious material. In the first case, clearly the air-impervious material will be cut by the cutting die and therefore also requires to be expendable.In the second case, on the other hand, the airimpervious material is not cut; however, it has been found that it does not readily survive a large number of cutting operations even when used outside the assembly.

It is the object of the present invention to provide an improved cutting system wherein a suction arrangement is utilised in combination with an assembly of cutting die, lay and cooperating cutting surface, but which does not require the use of expendable material.

The invention thus provides, in one of its several aspects, a cutting system comprising a cutting station at which a lay of material assembled between a cutting die and a cooperating cutting surface can be cut by pressing said die through said lay against said surface, means for advancing the assembly of the lay, cutting die and cooperating cutting surface to said station, enclosing means cooperable with the advancing means for forming therewith an enclosed chamber within which said assembly can be contained, said enclosing means comprising a top member and a skirt arrangement which extends between the top member and a surface portion of the advancing means and forms a seal therebetween, thus providing side walls of the chamber, and means for connecting the enclosed chamber to a suction source which is effective to cause the top member to be drawn more closely to the advancing means, the skirt arrangement yielding during such movement of the top member and the lay being compressed between the cutting die and the cooperating cutting surface, the arrangement being such that the lay is compressed as aforesaid prior to the assembly being advanced to the cutting station and is held thus compressed during such advance and subsequent cutting operation.

It will be appreciated that, by the provision of enclosing means for forming with the advancing means an enclosed chamber which can be connected to a suction source, and within which the assembly of cutting die, lay and cooperating cutting surface can be contained, there is no question of requiring an expendable material which will be cut in the cutting operation, or indeed which will be subject to any significant wear by the action of pressure-applying members when brought into contact therewith at the cutting station for a cutting operation to be performed.Further more, by using the cutting system in accordance with the present invention, work handling is significantly improved, since there is no longer any need to feed the expendable material over the assembly or over the lay, as the case may be, which is a time-consuming operation and also, especially in the case of lays which are relatively wide, will require two operators.

The advancing means of the system in accordance with the present invention may be of type comprising a frame within which the cutting die or cutting pad can be located, or alternatively may comprise a belt on which the cutting die or cutting pad can be supported.

Alternatively, again a cutting pad may be dispensed with and the cooperating cutting surface may be provided by a belt which forms part of the advancing means, but against which the cutting operation can take place.

Further for enhancing the work handling aspects of the system in accordance with the present invention, depending upon whether the lay is to be formed on a cutting die, located blades uppermost on the advancing means, with the cooperating cutting surface, e.g. provided by a cutting pad, placed on top of the lay, or whether the lay is formed on the cooperating cutting surface, which may be provided by a cutting pad or indeed by a belt.

as above described, with the cutting die being placed, blades down, on the top of the lay, the one of the cutting die and cutting pad placed on top of the lay is preferably secured to the top member of the enclosing means. In this way, when the top member is raised away from the advancing means, the cutting die or cutting pad is moved therewith, thereby relieving the operator of the need for handling it.

Further to enhance the work handling aspects of the system in accordance with the present invention, said system preferably comprises, arranged at one side of the cutting station, a support frame, carrier means for releasably supporting the top member, said carrier means being mounted on the support frame for heightwise movement thereon, to raise and lower said top member away from and towards the advancing means, and drive means for effecting such heightwise movement of the carrier means. By using such arrangement, especially where the cutting die or cutting pad is connected to the top member as aforesaid, the handling of the various components after the lay has been formed, takes place automatically under the control of the operator, but without physical exertion on his part.

In one cutting system in accordance with the present invention, the means for connecting the enclosed chamber to a suction source conveniently comprises an inlet carried by the top member. In this way, the advancing means of a cutting system can be of a conventional type, so that the possibilities of retro-fit are enhanced. Alternatively, where the advancing means comprises a belt, there may be provided at said one side of the cutting station a chamber which is arranged immediately beneath the belt and which is connected to a suction source, the belt being provided with one or more rows of perforations through which, when the enclosed chamber is formed by the enclosing means as aforesaid, said enclosed chamber communicates with the other chamber and thus is connected to the suction source.

Furthermore, using such an arrangement, the cutting system may further comprise, arranged at the other side of the cutting station, a further support frame, further carrier means for releasably carrying the top member, said further carrier means being mounted for heightwise movement on the support frame to raise and lower the top member as aforesaid, and further drive means for moving the top member, and in addition a further chamber may be provided at said other side of the cutting station, immediately beneath the belt of the advancing means, and be connected to the suction source.In this way, it can be envisaged that a lay will first be laid up at said one side of the cutting station and will be thereafter subjected to a cutting operation and then be moved to said other side of the cutting station, whereat the cut pieces will be removed and a further lay then be laid up at said other side of the cutting station, the whole process then being reversed as the advancing means returns the assembly to said one side of the cutting station. Furthermore, if desired in another embodiment of the cutting system in accordance with the present invention, the support frame, which is provided at said one side of the cutting station, may extend to the other side thereof, transfer means being provided for moving the carrier means, and the drive means therewith, from said one side to the other and back along a path remote from the cutting station. In this way, it can be envisaged that the top member, together with a cutting die or cutting pad connected thereto, can be circulated back to the one side of the cutting station without a need for passing it through said cutting station.

This arrangement is of course especially suitable where the cutting die is carried by the top member and the cutting surface is provided by a belt forming part of the advancing means.

The skirt arrangement of the enclosing means may be made of compressible material, e.g. a synthetic foam material, or alternatively may be in the form of a bellows, and is preferably carried by, and depends from, the top member.

In using the cutting system in accordance with the present invention, therefore, it will be appreciated that lays which are relatively deep, but of significantly compressible material may be cut using relatively shallow dies and using pressure-applying members which require only a relatively small "daylight". At the cutting station a platen press may be provided, comprising two platens one of which is movable relative to the other to perform cutting strokes, or alternatively a roller press may be provided. Whichever system is used, it will be appreciated that no expendable material is involved, while work handling is significantly improved at least so far as concerns the components of the cutting system.

There now follows a detail description, to be read with reference to the accompanying drawings, of a number of cutting systems embodying the present invention. It will of course be appreciated that these various systems now to be described have been selected merely by way of exemplification of the invention and not by way of limitation thereof.

In the accompanying drawings: Fig. 1 is a diagrammatic view of a cutting system in accordance with the invention showing a belt forming part of advancing means of the system and wherein an assembly of cutting die, lay and cutting head is utilised; Fig. 2 is a view similar to Fig. 1 but showing advancing means in the form of a socalled "chase"; Fig. 3 is a fragmentary view showing details of a top member and skirt arrangement of enclosing means cooperable with the advancing means of the system in accordance with the invention;; Fig. 4 is a view similar to Figs. 1 and 2, wherein the advancing means comprises a belt which provides the cooperating cutting surface and on which the lay is laid up, wherein a suction chamber is formed beneath the belt, and wherein the top member of the enclosing means can be transferred from one side of the cutting station to the other, remote from the cutting station; Fig. 5 is a fragmentary view in plan of part of the system shown in Fig. 4; and Fig. 6 shows details of a laying up table arranged "upstream" of the enclosing means.

With reference to Fig. 1, a first cutting system in accordance with the invention now to be described comprises a cutting press generally designated 10 arranged at a cutting station of the system and comprising an upper platen 12 movable heightwise relative to a fixed lower platen 14 to effect cutting strokes of the press. The lower platen 14 is provided with chamfered entry and exit portions (as seen in Fig. 1) in a conventional manner. The cutting system in accordance with the invention also comprises advancing means in the form of a belt 20 an upper reach of which extends at opposite sides of the cutting press 10 sufficiently to accommodate a lay L of material which is to be cut (or which has just been cut). The belt 20 is driven by any conventional means (not shown).

"Upstream" of the cutting press 10 is arranged a support frame 26 having four pistonand-cylinder arrangements 28 (two only shown in Fig. 1) piston rods 30 of which are provided with releasable clamping means 32 (shown only schematically) for releasably carrying a top member 34 forming part of enclosing means generally designated 36 of the cutting system. The piston-and-cylinder arrangements 28 thus constitute carrier means of said system.

The enclosing means 36 also comprises a skirt arrangement 38 (see also Fig. 3) in the form of a bellows by which, when the top member 34 is lowered towards the belt 20 by the operation of the piston-and-cylinder arrangements 28, sealingly engages with the belt and provides therewith an enclosed chamber. The bellows 38 may be made of any suitable durable substance. Instead of the bellows 38, alternatively a wall of synthetic foam material may be provided, or again a telescoping arrangement of any suitable type and material, the essential feature being that when it contacts the belt 20, it forms a seal.

The first cutting system also comprises means for connecting the chamber thus formed to a suction source, said means comprising an inlet 40 secured to the top member 34 and a suitable pipeline 42 extending therefrom.

When the chamber is enclosed as aforesaid, an assembly comprising a cutting die D, a lay L and a cutting pad P can be contained therein. This assembly may be arranged in such a manner that, as shown in Fig. 1, the cutting die D is placed, blades uppermost, on the belt 20 and the lay L is laid thereon, while the cutting pad P is secured to the top member 34 (see Fig. 3). Alternatively, the cutting pad P may be laid on the belt 20, with the lay L laid up thereon, while the cutting die D is secured, blades down, to the top member 34.

Whichever arrangement is used, in a cutting operation, pressure is applied to the assembly through the top member 34, the skirt arrangement 38 being compressed so as not to impede any dowmward movement of the member 34. The member 34 is made of any suitable material, e.g. steel, chipboard or other rigid material which is sufficiently strong firstly to support the pad P or die D and also to transmit the cutting force to the pad or die supported thereby.

In the operation of the first cutting system in accordance with the invention, with the assembly completed, upon actuation of a suitable control by the operator, the top member 34 is lowered under the action of the pistonand-cylinder units 28 until the skirt arrangement 38 is in sealing engagement with the belt 20, the assembly being contained therein.

In this condition suction is then applied through the inlet 40 to the enclosed chamber, said suction causing the top member to be drawn more closely to the belt 20, thereby compressing the material of the lay L. This further downward movement under the action of the suction applied may serve automatically to release the clamping means 32, or alternatively they may be released automatically or manually by actuation of a suitable control by the operator. The applied suction serves to maintain the lay L in compression and, while the lay is thus compressed, the advancing means is actuated to carry the assembly, including the top member 34, to the cutting station. Depending upon the lengthwise dimension of the lay, the lay is then cut in a single cutting stroke of the press 10 or progressively in a succession of such strokes.

Especially in the latter case, the assembly is gradually fed through the cutting press 10 to the other side thereof where it can be unloaded or from which, at the end of the final cutting stroke, it can be returned to the first side of the cutting station for unloading of the cut pieces and the laying up of a further lay.

It will be appreciated that, in using this first cutting system, the manhandling necessary for arranging the cutting pad and/or cutting die in position and for ensuring that the lay is properly compressed is reduced to a minimum.

Fig. 2 shows a second cutting system which is generally similar to that shown in Fig.

1 except that in this case the belt 20 has been replaced by a so-called chase 22 which is constituted by a frame 22 for receiving therein a cutting pad P or a cutting die D, blades uppermost, in the same manner as when using the belt of the system shown in Fig. 1. In addition, the frame or chase 22 has separate drive means in the form of a chain 24 which is entrained in the same manner as the belt 20 of the system shown in Fig. 1.

The chase is supported on a plurality of transverse rolls 18, in a manner which is conventional when chases are used.

For ensuring that an adequate seal is provided by the skirt arrangement 38 when it engages with the chase 22, the dimensions of the skirt 38 and chase 22 are such that the skirt rests upon a ledge 22a formed on the inside of the frame (as shown in Fig. 2). In addition, the die D or pad P forms a close fit with the frame in which it is accommodated, thereby reducing to a minimum any leakage which diminishes the effect of the suction.

Again as in the system shown in Fig. 1, the cutting die D may be arranged, blades upper most, in the chase 22 and the cutting pad P be secured to the top member 34, or alternatively the cutting pad 34 may be located in the chase 22, with the cutting die D, blades down, secured to the top member 34. Furthermore, the operation of the system shown in Fig. 2 is generally similar to that shown in Fig. 1.

Whichever of these two systems is used, the cutting die D utilised is of a conventional construction, being in the form of a board, e.g. of plywood in which strip steel blades are set. The cutting pad P is also of a conventional type, made e.g. of polypropylene or nylon.

With reference to Fig. 4 a third cutting system in accordance with the invention is described, again comprising a cutting press generally designated 10 having upper and lower platens 12, 14, together with advancing means in the form of a belt 20 driven by suitable drive means, as in the case of the first system referred to above. In the third cutting system, suction is applied from beneath the belt 20 rather than via an inlet 40 mounted on the top member 34 and to this end there extend, at both sides of the cutting station (cutting press 10), along opposite margins of the belt 20, elongated metal strips 44 each having disposed therein a groove 46 (Fig. 5), the grooves extending in the direction of advancing movement of the belt 20.In addition, ancillary strips 48 may be provided extending transversely of the belt 20, each strip 48 also having a groove 46 formed therein, the grooves 46 interconnecting and forming a single unitary chamber at each side of a cutting station (cutting press 10). The chamber thus formed is connected to a suction source (not shown) by means (not shown).

Extending along opposite margins of the belt 20, are two rows of perforations 50, each row being aligned with one of the lengthwise extending grooves 46. In addition, at spaced intervals the belt 20 is provided with transverse rows of perforations 52 which from time to time will be aligned with the grooves 46 in the transverse strips 48.

In order to achieve continuity through the cutting station, furthermore, the bed of the cutting press 10, providing the lower platen 14, is provided, at opposite sides thereof, with a groove 54, each groove being aligned with the lengthwise extending grooves 46 of the chambers formed at the opposite sides of the press.

In the third cutting system in accordance with the present invention an extended support frame generally designated 56 is provided, arranged to extend at both sides of the cutting station (cutting press 10). The frame 56 provides two rails 58 along which roller supports 60, each carrying a piston-and-cylinder arrangement 62, can run. The piston rods of the arrangements 62 support releasable clamping means 64 by which the top member 34 of the enclosing means can be supported, it thus being appreciated that in this case the top member is supported from above, as op posed to the first and second systems wherein said member is supported from be low.

In using the third cutting system in accor dance with the present invention a cutting die D is supported by the top plate 34, blades down, and is arranged to cut against a cutting surface provided by the belt 20 itself. Thus, with a lay laid up on the belt 20, the enclosing means is operated as in the case of the two preceding systems, the skirt arrangement 38 forming a seal against the belt outside the rows of perforations 50, and the enclosed chamber thus formed is subjected to suction and the lay L is compressed as above described.When the cutting operation on the lay L has been completed and the assembly is now located at the other side of the cutting station, the roller supports 60 together with the piston-and-cylinder arrangements 62 and their associated clamping means 64 (constituting the carrier means of the third system) can be transferred (by transfer means not shown) to the other side of the cutting station whereat, by extension of the piston-and-cylinder arrangement 62, the clamping means 64 can be brought into clamping engagement with the top member 34 of the enclosing means and can be raised from the lay of now cut pieces.

The top member 34 , together with the cutting die D secured thereto, can then be returned to the first side or remain at said other side according to where the next lay is being or has being laid up.

Whereas the use of the belt 20 in providing a cutting surface has been described with reference to the third cutting system, the belt of the first system could of course be so used, while in the third system a cutting pad P may be utilised either above or below the lay L.

Similarly the application of suction beneath the assembly could be used in systems otherwise generally similar to the first and second systems.

As is conventional in the laying up of lays of sheet material, laying up may take place at a station immediately beneath the enclosing means or alternatively may take place on a separate laying up table 70 which is to one side of such station. In this latter case, such table may be fixed (as shown in Fig. 6) and a cutting die D or cutting pad p, initially located therebeneath is driven towards said station, at the same time drawing the laid up lay from the laying up table onto the die or pad (or, where the cutting surface is provided by a belt, by moving a belt relative to the laying up table and drawing the lay therefrom), or alternatively the laying up table itself may be movable, the arrangement being such that it is first moved to the station, where it lies over the die or pad (or belt as the case may be) and then is retracted while the lay is held so that the latter is drawn from the table and deposited upon the die or pad (or belt) lying therebeneath.

In accordance with the present invention, furthermore, the laying up table 70 is constituted by a flotation table, that is a table having a work-supporting surface 72 in which is provided a plurality of apertures connected to a source of air under pressure, whereby the lay "floats" on a cushion of air, rendering it more easily slidable along the surface of the table.

It will of course be appreciated that such a table may form part of any one of the cutting systems herein described.

Claims (22)

1. A cutting system comprising a cutting station at which a lay of material assembled between a cutting die and a cooperating cutting surface can be cut by pressing said die through said lay against said surface, means for advancing the assembly of the lay, cutting die and cooperating cutting surface to said station, enclosing means cooperable with the advancing means for forming therewith an enclosed chamber within which said assembly can be contained, said enclosing means comprising a top member and a skirt arrangement which extends between the top member and a surface portion of the advancing means and forms a seal therebetween, thus providing side walls of the chamber, and means for connecting the enclosed chamber to a suction source which is effective to cause the top member to be drawn more closely to the advancing means, the skirt arrangement yielding during such movement of the top member and the lay being compressed between the cutting die and the cooperating cutting surface, the arrangement being such that the lay is compressed as aforesaid prior to the assembly being advanced to the cutting station and is held thus compressed during such advance and subsequent cutting operation.

2. A cutting system according to claim 1 wherein the cutting die is secured to the top member of the enclosing means.

3. A cutting system according to claim 2 wherein the cooperating surface is provided by a cutting pad on which the lay is laid up prior to the enclosing means being moved into an enclosing position.

4. A cutting system according to claim 3 wherein the cutting pad is carried in a frame forming part of the advancing means.

5. A cutting system according to claim 3 wherein the cutting pad is carried by a belt forming part of the advancing means.

6. A cutting system according to claim 2 wherein the cooperating cutting surface is provided by a belt on which the lay is laid up prior to the enclosing means being moved into an enclosing position and which forms part of the advancing means.

7. A cutting system according to claim 1 wherein a cutting pad, providing said cooperating cutting surface, is secured to the top member of the enclosing means.

8. A cutting system according to claim 7 wherein the cutting die is carried in a frame forming part of the advancing means and the lay is laid up thereon prior to the enclosing means being moved to an enclosing position.

9. A cutting system according to claim 7 wherein the cutting die is carried on a belt forming part of the advancing means and the lay is laid up thereon prior to the enclosing means being moved to an enclosing position.

10. A cutting system according to any one of the preceding claims comprising, arranged at one side of the cutting station, a support frame, carrier means for releasably supporting the top member, said carrier means being mounted on the support frame for heightwise movement thereon, to raise and lower said top member away from and toward the advancing means, and drive means for effecting such heightwise movement of the carrier means.

11. A cutting system according to any of the preceding claims wherein the means for connecting the enclosed chamber to a suction source comprises an inlet carried by the top member.

12. A cutting system according to claim 10 when tied to any one of claims 5,6 and 9 where at said one side of the cutting station a chamber is provided immediately beneath the belt of the advancing means, which chamber is connected to a suction source, and wherein the belt is provided with one or more rows of perforations through which, when the enclosed chamber is formed by the enclosing means, said enclosed chamber communicates with the other chamber and thus is connected to the suction source.

13. A cutting system according to claim 12 comprising, arranged at the other side of the cutting press, a further support frame, further carrier means for releasably carrying the top member said further carrier means being mounted for heightwise movement on the support frame to raise and lower said top member as aforesaid, and further drive means for moving the top member, and further wherein a further chamber is provided at said other side of the cutting station, immediately beneath the belt of the advancing means, and is connected to the suction source.

14. A cutting system according to claim 12 wherein the support frame extends to the other side of the cutting station, transfer means being provided for moving the carrier means, and the drive means therewith, from one side of the cutting station to the other and back along a path remote from the cutting station, and further wherein a further chamber is provided at said other side of the cutting station, immediately beneath the belt of the advancing means, and is connected to the suction source.

15. A cutting system according to any one of claims 12 to 14 wherein said other (and further) chamber is in the form a groove or grooves extending in the direction of movement of the belt.

16. A cutting system according to claim 15 wherein two grooves extends at opposite sides of the belt and are interconnected by a groove or grooves extending transversely of the belt.

17. A cutting system according to claim 16 wherein the belt is provided with two rows of perforations extending along the sides thereof and in the direction of movement thereof, and also at spaced intervals with transverse rows of perforations.

18. A cutting system according to any one of claims 15 to 17 wherein the lower platen of the cutting press has a groove or grooves formed therein and aligned with the groove or grooves constituting the other (or further) chamber.

19. A cutting system according to any one of the preceding claims wherein the skirt arrangement is made of compressible material.

20. A cutting system according to any one of claims 1 to 19 wherein the skirt arrangement is in the form of a bellows.

21. A cutting system according to any one of the preceding claims wherein the skirt arrangement is carried by, and depends from, the top member.

22. A cutting system constructed arranged and adapted to operate substantially as herein before described with reference to (a) Fig. 1 or (b) Fig. 2 or (c) Fig. 4 of the accompanying drawings.