EP0181269A1 - Press tool with processing parts exchangeable while under the press - Google Patents

Abstract

A press tool having working parts in the form of one or more dies (5) and one or more punches (12), and a blank holder (19) guiding this or these punches in their displacement and now in place against this or these dies, in its working stroke, a sheet (20) subjected to shaping is characterized in that it is provided between the die (s) (5) and the punch (s) (12) hold-down clamp (19) which performs at least one normal working stroke and two withdrawal strokes of your choice, namely a normal withdrawal stroke and an intervention withdrawal stroke which allows disassembly of these working parts of the tool in press.

Description

The present invention relates to a press tool with removable working parts in press, intended in particular for work carried out on sheets.

For the manufacture of sheet metal parts, tools are usually used which are mounted on presses to perform punching, stamping, bending, etc. operations. These tools generally include each, working parts such as punches and dies which are subject to more or less rapid wear, holding parts such as punch holders, die holders, fixing soles which are mounted respectively on the slide and the press table, and a blank holder usually intended both to securely hold a sheet subjected to shaping and to guide in their sliding these punches. Given the greater or lesser fragility of these punches, the press tools are usually designed so that at rest or at the end of their withdrawal or release stroke, the ends of their punches are still partially engaged in the guide holes trained in their blank holder. It follows that during their replacement, change or maintenance, these punches cannot be removed when these tools are still in presses, that is to say in place on the presses. To do this, these tools must be dismantled and removed from these presses. Thus, a replacement, maintenance or change operation of punches and dies in these known tools, which cannot be carried out under presses, is a waste of time and a relatively high cost of labor.

The aim of the present invention is to avoid these drawbacks, which makes it possible to produce an economical press tool with working parts, in particular punches, which can be dismantled in a press, intended to be mounted on a press for carrying out sheet forming operations. such as punching, stamping, bending, cutting, etc.

According to the invention, a press tool having working parts in the form of one or more dies and one or more punches, and a blank holder guiding this or these punches in their displacement and now in place against this or these dies, in its working stroke, a sheet subjected to shaping, is characterized in that it is provided, between the die (s) and the punch (s), a blank holder which performs at least one normal stroke of work and two withdrawal strokes of your choice, namely a normal withdrawal stroke and an intervention withdrawal stroke which allows disassembly of these working parts of the tool in press.

• - les figures la, lb, lc représentent des vues partielles et schématiques d'une coupe verticale d'un outil réalisé selon l'invention, montrant dans la l'outil fermé c'est-à-dire en fin de course de travail correspondant à la fin de course de descente d'un coulisseau d'une presse ; dans lb l'outil ouvert avec son serre-flan effectuant une course normale de retrait correspondant à la fin de la course de remontée d'un coulisseau d'une presse ; dans lc l'outil ouvert avec son serre-flan effectuant une course de retrait d'intervention correspondant à la fin de la course de remontée d'un coulisseau d'une presse ;
• - la figure 2 représente une vue partielle et schématique d'une coupe verticale d'un outil analogue à celle de la figure 1, monté sur une presse, montrant les positions relatives de leurs poinçon, matrice et serre-flan en fin de course de travail de l'outil ;
• - la figure 3 représente une vue de dessus partielle et schématique du serre-flan de l'outil de la figure 2 montrant dans la moitié de droite le serre-flan en position normale de travail ou de retrait et dans la moitié gauche le serre-flan en position d'intervention ;
• - la figure 4 représente une vue partielle schématique en perspective d'un dispositif de liaison coulissante reliant un serre-flan a une semelle de l'outil, et de son dispositif de commande.

To better understand the invention, an exemplary embodiment is illustrated below, illustrated by the attached drawings,

• - Figures la, lb, lc show partial and schematic views of a vertical section of a tool produced according to the invention, showing in the closed tool that is to say at the end of the corresponding working stroke at the end of the downhill stroke of a press slide; in lb the open tool with its blank holder performing a normal withdrawal stroke corresponding to the end of the ascent stroke of a slide of a press; in lc the open tool with its blank holder performing an intervention withdrawal stroke corresponding to the end of the ascent stroke of a slide of a press;
• - Figure 2 shows a partial and schematic view of a vertical section of a tool similar to that of Figure 1, mounted on a press, showing the relative positions of their punch, die and blank holder at the end of travel tool work;
• - Figure 3 shows a partial and schematic top view of the blank holder of the tool of Figure 2 showing in the right half the blank holder in normal working or withdrawal position and in the left half the clamp blank in intervention position;
• - Figure 4 shows a partial schematic view in perspective of a sliding connection device connecting a blank holder to a sole of the tool, and of its control device.

The invention is applicable both to a recovery tool and to a tool to follow. We usually call a recovery tool, a press tool that operates only once, on a sheet metal blank to give it a more or less complex shape. Operations such as cutting, folding, stamping, etc. generally cannot all be done with a single tool but they are done on a range of recovery tools. Called tracking tool, in general a tool comprising several aligned work stations, one arranged after the other on which a strip of sheet metal or metal is scrolled in a determined pitch to achieve on this strip of sheet metal by each workstation a predetermined operation such as punching, stamping, bending, cutting ... and obtain at the exit of the last station a finished part detached from this strip of sheet metal and having a more or less complex shape.

A press tool 1 produced according to an exemplary implementation of the invention, illustrated schematically and partially in FIGS. 1 to 4, is a tool of the tool to be followed type, intended to be mounted on a press 2 including the table 3 and the slide 4 are shown schematically in broken lines.

The press tool 1 comprises at least firstly a die 5 held by a die holder 8 and a lower fixing base 11 which is mounted on the table 3 of the press 2, secondly a punch 12 held in a punch holder hoop 15 and an upper fixing sole 18 which is mounted on the slide 4 of the press 2, and thirdly a blank holder 19 disposed between this die 5 and this punch and intended both to hold in place a sheet metal strip 20 against this die 5 and to guide this punch in their movement 12. The die 5 and the die holder 8 fixed on their common sole 11 are removable and removable with respect to the latter. The same applies to the punch 12 and the punch holder 15 relative to the upper fixing flange 18.

The end of the normal working stroke of the slider 4 of the press 2 which coincides with the end of the normal working stroke of the tool 1 is shown in FIG. 1 a while the end of the normal withdrawal stroke of the slider 4 of the press 2 which coincides with the end of the normal withdrawal stroke of the tool 1 is illustrated in FIG. 1b.

At the end of a normal tool withdrawal stroke 1, the punch 12 and the blank holder 19 move away from the die 5 (FIG. 1b), but this punch still remains partially engaged in a shape or corresponding guide hole. 21, made in the blank holder 19. In such relative positions of this punch 12 and this blank holder 19, it is difficult and even impossible to remove this punch when the tool 1 remains fixed on the press 2, in other words, the disassembly of this punch 12 in the press proves difficult or impossible.

According to an important characteristic, the press tool 1 is provided between the punch 12 and the die 5 with a blank holder 19 which performs at least one normal working stroke and two retraction strokes of your choice, namely a normal stroke withdrawal and an intervention withdrawal run. In its normal working stroke, the blank holder 19 guides the punch 12 in their movement and maintains, at the end of this stroke, the sheet metal strip 20 firmly in place against the matrix 5. At the end of its normal withdrawal stroke, the blank holder 19 is released from the die 5 but the punch 12 still remains partially engaged in the corresponding guide hole 21 in this blank holder 19.

In the case of an intervention withdrawal stroke, the blank holder 19 emerges from the die 5 and the punch 12 exits from its guide hole 21 at the end of the press slide rise travel and emerges completely from this blank holder, as illustrated in figure lc.

The blank holder 19, the punch 12 and its punch holder 15 and the upper fixing sole 18 carried by the slide 4 of the press 2, are guided respectively in their movement during their working and withdrawal strokes, opposite -screw of the die 5 and its die holder 8 and the bottom flange 11 fixed on the table 3 of the press 2, by four columns 22 (FIG. 3), one of which is shown in partial section in FIG. 2. The guide columns 22 are, in the example illustrated, ball columns of a known type.

According to another important characteristic, the blank holder 19 for carrying out its normal working stroke and its two withdrawal strokes of choice, is mechanically connected to the upper fixing base 18 which supports the punch 12 and its punch holder 15 by sliding connection devices 23 which each include two stops of choice, one marking the end of its normal withdrawal stroke where the punch 12 is still partially engaged in the blank holder 19, and the other representing the end of its intervention withdrawal stroke where the punch 12 is completely outside of this blank holder 19.

These sliding connection devices 23 which are four in number in the example illustrated (FIG. 3) comprise (FIGS. 1a, 1b, 1c, 2, 4) each a sheath 25 fixed to the blank holder 19, a retaining screw with a stop head 24 fixed to the upper sole 18 of the tool, through this sheath 25 and a movable or retractable fork 26 engaging on this screw 24 between the head of the latter and the bottom of the sheath 25. The sheath 25 and the movable fork 26 respectively serve as the intervention withdrawal end-of-travel stop and the normal withdrawal end-of-travel stop. The sleeve or stop 25 is constituted by a part provided with a longitudinal section having the shape of an inverted elongated U with a drilled bottom for the sliding of the retaining screw with stop head 24, with side wall provided with a passage opening 31 for the fork 26, and with a free end provided with a retaining shoulder. These shoulders can be provided with holes for fixing screws 27. The sheath or stop 25 has a length greater than the thickness of the blank holder 19 so that when this sheath 25 is fixed by screws 27 on this clamp blank 19 through a corresponding hole 28 formed in the latter, the bottom of this stop 25 projects from the face of the blank holder opposite the fixing face, of a length equal to the thickness of the fork or stop retractable 26 increased by the thickness of the bottom of this sheath or stop 25. The retractable fork or stop 26 is constituted by a piece with two branches extended by a handle 29 which can be provided laterally with two wings 30 not shown. These wings 30 give the fork or stop 26 good stability in its movement during its retraction or its establishment. In its implementation (Figures la, lb, 2, 3 right) the fork or stop 26 slides on the surface of the blank holder 19 and enters the sheath or stop 25 through the passage opening 31 and its handle 29 made laterally protruding outside the sheath 25. In its retraction (Figures 1c and 3 left) the fork or stop 26 slides on the surface of the blank holder 19 and leaves the sheath or stop 25 through the passage opening 31.

According to another characteristic, the four forks or stops 26 are fixed to the same control device 32 which communicates to them a simultaneous movement in their movement during their positioning or their retraction.

This control device 32 comprises a front rod 33 and two sliding lateral tie rods 34, 35 to which the forks or stops are fixed 26. The frontal rod 33 is provided with handles 36 and the two tie rods 34, 35 are mounted sliding along the edges sides of the blank holder 19 according to a known technique.

During normal operation of the tool 1 in the press 2, in the sliding connection devices 23, the forks or stops 26 are simultaneously inserted in the corresponding sleeves or stops 25 between the bottoms thereof and the heads d 'stop of the sliding retaining screw 24, and in this case the blank holder 19 has a normal working stroke and a normal withdrawal stroke. At the end of the normal working stroke of the tool 1, the punch 12, the die 5, the blank holder 19 and the sheet metal strip 20 respectively assume the positions represented in FIGS. 1a, 1b and 2 and at the end of a normal tool withdrawal stroke 1, in the sliding connection devices 23, the heads of the retaining screws 24 are stopped by the forks or stops 26, and in tool 1 the punch, matrix and blank holder have positions respectively partially illustrated in Figure lb.

During a replacement, maintenance or change of one or more punches 12 in the sliding connection devices 23, the forks or stops 26 are simultaneously retracted, that is to say withdrawn outside the sleeves or stops 25, using the control device 32, and in this case the blank holder 19 has a normal working stroke similar to that of normal operation of the tool 1 and an intervention withdrawal stroke illustrated in FIG. where the heads of the retaining screws 24 are stopped respectively by the bottoms of the sleeves or stops 25, and not by the forks or stops 26 which are already retracted or removed. As a result, in this intervention withdrawal stroke, the blank holder 19 moves away from the upper fixing sole 18 which carries the punch or punches, by a distance (FIG. 1c) greater than the distance in the case of a normal blank holder withdrawal stroke (FIG. 1b) so that the punch (s) 12 are completely disengaged from the blank holder 19 (FIG. 1c). The punch (s) 12 can thus be easily disassembled or removed at the same time as the die (s) 5 without requiring disassembly of the tool 1 outside the press to effect their change, replacement or maintenance.

The tool 1 produced according to the invention thus makes it possible to avoid a waste of time and an additional cost of labor.

Claims (7)

1. Press tool having working parts in the form of one or more dies (5) and one or more punches (12) and a blank holder (19) guiding this or these punches in their movement and now in place against this or these dies in its working stroke a sheet (20) subjected to shaping, characterized in that it is provided between the die (s) (5) and the punch (s) (12) of a blank holder (19) which performs at least one normal working stroke and two withdrawal strokes of choice, namely: a normal withdrawal stroke and an intervention withdrawal stroke which allows disassembly of these working parts of the tool in press. 2. Tool according to claim 1, having an upper sole (18) fixed to a slide (4) of a press (2) and carrying the punch or punches (12) and punch holder, and a lower sole (11) fixed to a table (3) of this press and carrying the die (s) (5) and die holder, characterized in that the blank holder (19), to carry out its normal working stroke and its two retraction strokes at choice, is mechanically connected to the upper sole (18) of the tool by sliding connection devices (23) which each comprise two optional stops (25, 26) one marking the end of its normal travel withdrawal where the punch (s) (12) remain partially engaged in the blank holder (19) and the other representing the end of its intervention withdrawal stroke where the punch (s) (12) are completely outside this blank holder (19). 3. Tool according to claim 2, characterized in that the sliding connection devices (23) each comprises a retaining screw with a stop head (24) fixed to the upper sole (18) of the tool, a sheath or stop (25) slidably mounted on this screw (24) and fixed on the blank holder (19) to serve as an intervention withdrawal end stop and a fork or stop (26) which, depending on its engagement in this sleeve between the retractable head of this screw retainer (24) and the bottom of this sheath (25) or its release from this sheath (25) determines a normal withdrawal stroke of this blank holder (19) or an intervention withdrawal stroke of this blank holder (19). 4. Tool according to claim 3, characterized in that in the sliding connection devices (23), the sheath or stop (25) is constituted by a part provided with a longitudinal section in the form of an elongated, inverted U, with side wall provided with a passage opening (31) for the fork or stop (26) and with a free end provided with retaining shoulder. 5. Tool according to one of claims 3 and 4, characterized in that in the sliding connection devices (23), the fork or stop (26) is constituted by a part with two branches extended by a handle (29) which protrudes laterally outside the sheath or stop (25). 6. Tool according to one of claims 3 to 5, characterized in that in the sliding connection devices (23) the forks or stops (26) are fixed to the same control device (32) which communicates to them a simultaneous movement in their movement, during their installation or their retraction. 7. Tool according to claim 6, characterized in that the device for controlling the forks or stops (26) of sliding connection devices (23) comprises a front rod (33) provided with handles (36), and two sliding lateral tie rods (34, 35) to which these forks or stops (26) are fixed.

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