GB2184968A - Die press - Google Patents

Abstract

An upper die 4 having a lower cutting edge 12 is traversable over a lower sheet 11 of material by relative movement of the die and the sheet into successive ones of a series of positions in each of which the die is reciprocal perpendicularly to the plane of the sheet thereby to cut a part out of the sheet, the die is apertured therethrough at 14 in the direction in which the die is reciprocal, the size, configuration and alignment of the aperture relative to the cutting edge of the die being such that a part cut by the die can readily pass through the aperture, and collecting means 16 is located for collecting the cut part from the die through the aperture. The means 16 are resiliently deformable spring blades 18 mounted on struts 17. Suction cups, a sweep arm or rotatable brush may take off the topmost cut parts from means 16 in succession. Alternatively suction means or gripper fingers act directly above the die aperture 14. In a further alternative, a foam lined tube (22, Fig. 2) may be detachably mounted on the die platen. <IMAGE>

Description

SPECIFICATION Die Press This invention relates to die presses and, more particularly, to die presses of the type in which an upper die having a lower cutting edge is traversable over a lower sheet of material by relative movement of the die and the sheet into successive ones of a series of positions in each of which the die is reciprocal perpendicularly to the plane of the sheet thereby to cut a part out of the plane of the sheet.

The material used in such die presses may be in the form of discrete sheets or may be in the form of a roll of sheet material.

Conventionally, such die presses are of one of either two types. In one type, a matched pair of die sets are used, an upper and a lower die. In this type, in the process of cutting, one die forces the part cut from the sheet through the complementary aperture in the other die. The later-cut parts push the earliercut parts through the aperture to be collected from the other die. However, matched die sets are expensive and, in machines in which the traverse of the die-set across the sheet is effected by movement of the die-set, complicated control would be necessary in the movement of the upper and lower dies to ensure perfect alignment of the two dies of the set. In the alternative type, only a single usually upper die is used, the sheet material being positioned on a bed of usually soft material which supports the sheet being cut.In this type of die press, recovery of the cut parts relies generally upon the cut part being retained in the sheet. Sometimes the cut part is not so retained and has to be recovered by hand from the press. In any case, for those cut parts which are retained, they then have later to be extracted from the sheet. This recovery is effected either by hand with the labour expense that this incurs or mechanically. Mechanical recovery is by no means certain as parts sometimes continue to "hang" in the sheet even after attempted mechanical removal.

Die presses are also known in which a single hollow die cuts upwardly into a sheet positioned above the die. In such presses, the cut part passes through the die to be collected from therebelow.

However, such presses have the disadvantage that the cut web tends to "hang" on the die and means have to be provided to ensure release of the cut web from the die before the die/sheet can be moved relative to each other to the next successive cutting position.

The present invention avoids the expense and unreliability of these conventional presses.

Accordingly, the present invention provides a die press of the type in which an upper die having a lower cutting edge is traversable over a lower sheet of material by relative movement of the die and the sheet into successive ones of a series of positions in each of which the die is reciprocal perpendicularly to the plane of the sheet thereby to cut a part out of the sheet and in which the die is apertured therethrough in the direction in which the die is reciprocal, the size, configuration and alignment of the aperture relative to the cutting edge of the die being such that a part cut by the die can readily pass through the aperture, and collecting means for collecting the cut part from the die through the aperture.

The die press may be of the type in which the die is traversable across the sheet by movement of the die across the sheet which is held stationary during the traversing of the die and the die may be vertically reciprocal to cut a part out of the sheet. In the alternative, the sheet may be traversable across the die by movement of the sheet or both the sheet and the die may be traversable so that the combined movement of the sheet and the die effects successive positioning of the die relative to the sheet into successive cutting positions.

The die may be carried by and below a platen which has therethrough an aperture constituting a continuation of the aperture through the die, the size, configuration and alignment of the aperture in the platen relative to the cutting edge also being such that a part cut by the die can readily pass through the aperture in the platen to allow the collection herethrough of the cut part.

The collecting means may comprise a structure having therethrough a path constituting a continuation of the aperture through the die, the size, configuration and alignment of the path in the structure relative to the cutting edge also being such that a part cut by the die can readily pass through the aperture in the platen. In this case, the structure may be provided with retaining means by which parts cut by the die can be releasably retained in a stack in the path in the structure or, alternatively, may comprise resiliently deformable means arranged in the path in the structure by which the parts cut by the die are releasably gripped. In this latter case, the resiliently deformable means may be constituted by a lining of the path which may be of foam material.The resiliently deformable means may alternatively be constituted by a series of resiliently deformable members arranged around the periphery of the path and extending longitudinally thereof. In a further alternative, the collecting means may be comprised by a brush or the like which sweeps across either the exit from the path of the parts cut, by the die or the top of the retaining means successively to sweep-off the cut parts may be onto a conveyor.

The collecting means may include removing means by which a part cut by the die can be removed from the die. The collecting means may include removing means by which the successive top ones in the stack of cut parts in the path in the structure can be removed from the stack. In either case, the removing means may comprise a suction cup movable to and from a first collection position in which the cup engages and secures to the cut part and to and from a second delivery position in which the suction cup detaches from and releases the cut part. The arrangement may be such that more than a single cut part is removed at any one time from the collecting means.

In the above constructions, the sheet may, of course, be a laminate from which parts are to be cut.

In this case, of course, the cut parts will be multi layer.

Embodiments of the present invention will now be described in greater detail, by way of example only, with reference to the accompanying drawings of which: Fig. 1 shows a schematic arrangement of one embodiment of the invention, and Fig. 2 shows a schematic arrangement of part of an alternative embodiment.

As shown in Fig. 1,the die press comprises a bed 1 reciprocal vertically with respect to which are push/pull rods 2. Extending between the top extremity of the rods 2 are a pair of tracks 3 of which onlythe rearward one can be seen in Fig. 1. The tracks 3 are thus also vertically reciprocal with the rods 2.

The die 4 of the press is carried by a plate 5 itself removably carried on slides 6. The slides 6 are mounted on an upper platen 7 movable to the left and right as viewed in Fig. 1 on the tracks 3. By virtue of the movement of platen 7 thus provided, the die 4 can be traversed in the x axis into successive ones of a series of positions.

Positioned on the bed 1 of the press is a bottom horizontal platen 8 on top of which, positioned by flanges 9, is a bed 10 of relatively soft material. On this bed 10 is laid a sheet 11 of the material from which parts are to be cut by the die 4. To effect such cutting, the die 4 is provided at its lower extremity with a cutting edge 12. The flanges 9 prevent transverse movement of the sheet 11 in the x axis which allowing movement of the sheet 11 in the direction of the flanges 9 in they axis. Thus, by combined movement of the die 4 on the tracks 3 in the x axis and of the sheet 11 in the direction of the flanges 9 in they axis, the die 4 can be positioned as required in any location relative to the sheet 11.

As so far described, the die press is of conventional construction and operates by the die 4 being initially positioned above one corner of the sheet 11 by appropriate indexing of the movements of the upper platen 7 on the tracks 3 and the bed 10 on the lower platen 8. When in this position, the tracks 3 are reciprocated downwardly and then upwardly by the rods 2 so that the die 4 is correspondingly reciprocated into engagement with the sheet 11. Such reciprocation of the die 4, by virtue of the cutting edge 12 cuts out of the sheet 11 a part of complementary peripheral shape to that of the cutting edge 12. After the first such reciprocation of the die 4, the die 4 is then stepped on to its next designated position determined by appropriate indexing of the platen 7 and the bed 10.When in that next position, the die 4 is again reciprocated by the vertical reciprocation of the tracks 3 to cut the next of the parts from the sheet 11. This operation is then repeated several times so as to effect the cutting out of a number of parts from the sheet 11.

In the conventional press, the parts cut out are left in the sheet 11 which, after subsequent removal of the sheet 11 from the press, are then manually or mechanically in a separate operation removed from the sheet 11.

In some types of die press, the die 4 is also rotatable about the vertical axis 13 so that the die 4 is indexable relative to the sheet 11 not only in the x andy axes but also rotationally to allow for the closest interlocking of the cut parts with consequential minimisation of waste.

In accordance with the present invention, the die 4 has therethrough an aperture 14 the size, configuration and alignment of which relative to the cutting edge 12 is such that a part cut out of the sheet 11 by the die 4 can readily pass through the aperture 14. The plate 5 is also provided with an aperture 15 which is of similar size, configuration and alignment as the aperture 14.

Mounted on and so as to extend above the platen 7 is a structure 16 comprised by a series of struts 17 arranged around the aperture 15 in the platen 7.

Each strut 17 carries one of a series of resilientlydeformable spring blades 18 which extend longitudinally of and project slightly into a path 19 through the structure 16. By virtue of the arrangement of the struts 17 around the periphery of the aperture 15, the struts 17 will collectively define the path 19 as having a size, configuration and alignment similar to the apertures 14 and 15.

The die 4 and its cutting edge 12 are designed such that any part cut out from the sheet 11 by reciprocation of the die 4 will be held in the lower end of the die 4. Thus, upon vertical reciprocation of the die 4 at the succession of its positions as it is traversed across the sheet 11, the earlier-cut parts will be pushed upwardly by the later-cut parts, through the aperture 14 in the die 4 and the aperture 15 in the plate 5 the path l9ofthestructure 16 where they will be collected being resiliently gripped by the springs 18.

Particularly if the length of the path 19 and the apertures 14 and 15 are of sufficient length to accommodate all of the parts which can be cut from a single sheet 11, the cut parts can be left in position until the sheet 11 has been fully cut out; the cut partsthen being removed (manually or mechanically) whilst the cut sheet 11 is being removed and repiaced by a new sheet.

Alternatively, means may be provided for removing the cut parts as they appear at the top of the path 19. Their means may be a suction cup operable to be moved to and from a first collection position in which the cup engages and secures the topmost of the parts stacked in the path 19 and to and from a second delivery position in which the suction cup detaches from and releases the part which it has previously picked up. In another form, the means may comprise a sweep arm or rotating brush which sweeps over the stack of parts in the path 19 and sweeps off the topmost part onto a conveyor which takes away the parts.

Turning now to Fig. 2, the die press (not shown) is of the same general type as that previously described with reference to Fig. 1 and so requires no further description here. In this embodiment, like reference numerals indicate like parts to those shown in Fig. 1.

In this embodiment, the structure 16 comprises an outer container 20 which is secured at its lower end to the platen 7 and has at its upper end a releasable catch 21 which serves to locate a tube 22 relative to the die 4 in an aperture 23 in the platen 7. The tube 22 is internally lined with foam material 24 which acts in a manner comparable to the springs 18 of Fig. 1 frictionally to grip cut parts which are pushed upwardly (as previously described) into the path 19.

By virtue of the releasable catch 21, the foamlined tube 22 is removable so that when it is full of cut parts, it can be removed for emptying and replaced by another empty replacement tube 22.

The outer container 20 may be set in bearings which allow rotation of the total assembly of Fig. 2 about its vertical axis thereby providing rotational indexing of the die 4 as well as its location relative to the sheet 11 inthexandyaxes. By such an arrangement the most economical cutting of the sheet 11 can be effected.

With the construction of Fig. 2, the whole structure of that Figure may be reciprocal vertically to effect cutting rather than such reciptrocation being effected by the rods 2 of Fig. 1. Such reciprocation of the structure of Fig. 2 could be effected by dual fluid-powered cylinders effective between the tracks 3 of Figure 1 and the outer peripherai part of the platen 7.

In the above described embodiments, there is provided the structures 16 which serve as collecting means for the cut parts. However, alternative forms of collecting means could be used. For example, there has been described above suction-cup means for removing the cut parts. Such suction-cup means could be used without the structures 16. In this case, the suction-cup means would then be so arranged as, after each cutting reciprocation of the die 4, to collect from the die 4 through the apertures 14 and 15 each part as it was cut out thus effecting a one-ata-time collection of the parts.

When such suction-cup means are used (with or without the structure 16), there may be provided a plurality of such cups which, sequentially, pick up successive ones of the cut parts. In this case, the cups may be a pair 180 degree displaced one from the other such that whilst one is detaching and releasing at the delivery position a previously picked-up part, the other is engaging and securing the next part at the collection position.

Whilst a suction-cup system has been described, other means for picking out the cut parts may be used. For example, a gripping action may be employed by using fingers which can be inserted into the path 19 or the aperture 14 (as the case may be) to grip the edges of the cut part or parts and lift it or them out and away from the press.

Particularly with the construction of the structure 16 shown in Fig. 1, the parts defining the path 19 may be adjustable inwardly and outwardly of the path 19 so as to provide universitalityfor accommodating cut parts of a variety of shapes and dimensions.

Whilst as above described, the platen 8 is horizontal and the direction of reciprocation of the die 4 vertical, the press could be tilted so that the platen 8 is inclined to the horizontal and the direction of reciprocation of the die 4, whilst still being perpendicular to the plane of the sheet 11, being similarly tilted to the vertical Such an arrangement, with the structures 16, would allow the topmost cut part automatically to fall out of the path 19 as it reached the top thereof. However, the present invention is only concerned with die presses of the type in which an upper die is generally above a lower sheet of material to be cut.

Another method for the collection of the parts would be a vacuum system by which the cut part was sucked by the vacuum through the aperture 14 as soon as it was cut or by which the topmost of the cut parts was sucked off the stack of parts in the path 19. The thus removed parts could then be carried away from the press down a vacuum tube. In such an alternative, of course, the vacuum could be controlled in sympathy with the reciprocation of the die 4. In an alternative, more than one cut part may be sucked out by the vacuum system at any one time.

In the above described embodiments, the die 4 is shown and described as being its traversable over the sheet 11. Conversely, of course, the die 4 could be fixed and the bed 8 (or, at least, the sheet 11) then straversed under the die 4. With this arrangement, a plunger might be mounted beneath the sheet 11 in line with the aperture 14, the plunger being operated upon the completion of the cutting out of a partto push the part partway up the aperture 14.

This arrangement might be such that the plunger is operated only at the end of a cutting run to remove the last few cut parts from the die 4 prior to its removal and replacement by an alternative die 4.

When as is sometimes the case further to minimise wastage, a plurality of dies 4 are used on a single upper plate 5, each die 4 may then have associated with it a structure 16 such as is shown in either Fig. 1 or Fig. 2 or other collecting means.

In certain cases it is advantageous to combine dies of the type described with dies of the type in which the parts are left in the web. In this case relative adjustment of the one die to the other may be incorporated to ensure a proper cutting action of both types. Such an arrangement is particularly beneficial in facilitating the removal of circular scrap material such as that from stud holes in gaskets.

Relative adjustment of such, normally, small tubular dies with the main die may advantageously be effected by means of a threaded exterior to said tubular die.

Whilst, in the above described embodiments, sheet 11 is implied as being a discrete sheet, the sheet may be in a roll which is stepwise fed through the press.

The die 4 may be detachably secured to the plate 5. Conveniently such securing may be effected by a series of longitudinally-adjustable fingers extending radially-outwardly from the die 4 and arranged to grip the die 4 by the inner extremities of the fingers.

The fingers may be longitudinally-adjustable by screws and locking nuts or by fluid-pressure cylinders.

A further means for controlling the movement of the cut parts in the retaining means and allowing for their simple removal at the appropriate time is by means of a non return device at the lower end of the retaining means. This may be of resilient construction similar to one of those already described as extending over the greater part of the length of the retainer path or, alternatively, it may comprise one or more hinged flaps. Means providing resistance to the successive movement of the parts through and beyond the non return device may also be included and may be in the form of a frictional piston (which may be of foam) inserted from the top of the retaining means to bear against the rising stack of parts. Said non return device may be manually or automatically releasable to facilitate the removal of the cut parts from the retainer.

Claims (16)

1. A die press of the type in which an upper die having a lower cutting edge is traversable over a lower sheet of material by relative movement of the die and the sheet into successive ones of a series of positions in each of which the die is reciprocal perpendicularly to the plane of the sheet thereby to cut a part out of the sheet and in which the die is apertured therethrough in the direction in which the die is reciprocal, the size, configuration and alignment of the aperture relative to the cutting edge of the die being such that a part cut by the die can readily pass through the aperture, and collecting means for collecting the cut part from the die through the aperture.

2. A die press as claimed in Claim 1, wherein the die press is of the type in which the die is traversable across the sheet by movement of the die across the sheet which is held stationary during the traversing of the die.

3. A die press as claimed in Claim 1 or Claim 2, wherein the die is vertically reciprocal to cut a part out of the sheet.

4. A die press as claimed in any one of the preceding Claims, wherein the die is carried by and below a platen which has therethrough an aperture constituting a continuation of the aperture through the die, the size, configuration and alignment of the aperture in the platen relative to the cutting edge also being such that a part cut by the die can readily pass through the aperture in the platen to allow the collection of the cut part.

5. A die press as claimed in any one of the preceding Claims, wherein the collecting means comprises a structure having therethrough a path constituting a continuation of the aperture through the die, the size, configuration and alignment of the path in the structure relative to the cutting edge also being such that a part cut by the die can readily pass through the aperture in the platen.

6. A die press as claimed in Claim 5, wherein the structure is provided with retaining means by which parts cut by the die can be releasably retained in a stack in the path in the structure.

7. A die press as claimed in Claim 6, wherein the retaining means comprises resiliently deformable means arranged in the path in the structure by which the parts cut by the die are releasably gripped.

8. A die press as claimed in Claim 7, wherein the resiliently deformable means constitutes a lining of the path.

9. A die press as claimed in Claim 8, wherein the lining is formed of foam material or brushstrip.

10. A die press as claimed in Claim 7, wherein the resiliently deformable means are constituted by a series of resiliently deformable members arranged around the periphery of the path and extending longitudinally thereof.

11. A die press as claimed in any one of Claims 6 to 10, wherein the retaining means is effective in only the lower ones of the cut parts in the path.

12. A die press as claimed in any one of the preceding Claims, wherein the collecting means includes removing means by which a part cut by the die can be removed from the die.

13. A die press as claimed in any one of the Claims 6 to 11 inclusive, wherein the collecting means includes removing means by which the successive top ones in the stack of cut parts in the path in the structure can be removed from the stack.

14. A die press as claimed in Claim 12 or Claim 13, wherein the removing means comprises a suction cup movable to and from a first collection position in which the cup engages and secures to the cut part and to and from a second delivery position in which the suction cup detaches from and releases the cut part.

15. A die press as claimed in any one of Claims 5 to 11 inclusive, wherein the structure or part thereof is replaceably removable from the press for emptying and replacement.

16. A die press substantially as herein described with reference to and as illustrated in Fig. 1 or Fig. 2 of the accompanying drawings.