EP1264647A1 - Press brake for sheets with a movable workpiece stop device - Google Patents

Abstract

The invention relates to a mobile device for abutment fingers for a press brake. It comprises a support rail (8) mounted in the inner zone (5) of the press brake (1), a guide carriage (10) provided with blocking means capable of sliding along the support rail (8) and comprising two side guides (12, 13), a transport carriage (11) mounted on the guide carriage (10) and guided by the side guides (12, 13). The transport carriage (11) carries at its front end a removable stop pin (9) and at its rear end a drive motor (15). A worm (17a) and nut (17b) drive (17) is mounted on the transport carriage (11) and is coupled to the drive motor (15). The nut (17b) cooperating with the ball screw (17a) is fixed on the guide carriage (10) on the side turned away from the folding plane (4) by means of a flange (18) which passes through a recess oblong (19). In the advanced position of the transport carriage (11), the rear half thereof comprising the ball screw (17a) protrudes on either side of the vertical faces of the guide carriage (10), faces parallel to the folding plane .

Description

The present invention relates to a press brake for sheets, provided with a mobile device of stop fingers, said press comprising a swan-neck frame having on the side front a fixed lower deck, the upper side of which serves to support a folding die and a vertically movable upper deck in alignment with the lower deck and carrying by its lower part one or more folding tools cooperating with said die and located in a vertical plane separating an interior area from the press brake an external or frontal area in which the press operator folder can work without danger of accident, while the device stop finger movable includes a support rail which is arranged in the interior area of the press brake, runs parallel to the folding die and is movable at least vertically, a support for each stop finger resting on said rail and movably mounted on the latter parallel to said matrix as well as a carriage capable move the stop fingers at least partially out of the area inside of the press brake to the front outside area of the press brake.

A press brake for sheets of the type comprising a mobile stop finger device is known from the application of Patent EP 0 650 782 A1. In this case, the support rail is associated with a first carriage carrying said rail and movable vertically on vertical slides of a second horizontally movable carriage and perpendicular to the vertical plane passing through the folding matrix, the two carriages being arranged in the interior area of the press folder.

A disadvantage of this arrangement is that the stop finger supports cannot leave the interior area of the press brake so that the replacement of a stop finger forces the operator to advance his hands in said interior area and place these between the tool and the folding die. Like elsewhere, the commonly used stop fingers have the same length, they cannot adapt without exchange of at least one abutment finger to a sheet, the abutment edge of which is cut into steps or some other layered way. Yet another drawback of the device moving of stop fingers consists of the need to move the support rail each time the positioning of the stop edge of the sheet metal is changed from the folding die.

The object of the present invention is to overcome the drawbacks known above and to offer in combination with a press brake a movable stop finger device allowing each finger to abutment to protrude entirely beyond the vertical plane containing the folding edge of the folding die and being positioned individually in distance from said vertical plane.

This object is achieved in accordance with the invention because the support rail is mounted in the interior area of the press brake a determined distance from the vertical folding plane, which a guide provided with locking means is capable of sliding the along the support rail and has two guides on its upper face lateral extending perpendicular to the folding plane, that a transport carriage is mounted on the guide carriage and is guided by the latter's lateral guides in its back and forth movements perpendicular to said folding plane, that the transport carriage has a longitudinal extension greater than the width of the guide carriage and has a finger at its front end located on the side of the folding plane removable stopper and at its rear end the motor housing drive, that a worm drive is mounted on the rear half of the transport trolley via bearings integral with said transport carriage and receiving the ends of said ball screw, as the rear end of said ball screw which extends perpendicular to the bending plane is coupled to the output shaft of the drive motor, and that the nut cooperating with the ball screw is fixed to the guide carriage on the side diverted from the folding plane by means of a flange which crosses an oblong recess formed in the bottom of the transport trolley over the entire length active ball screw and in the advanced position of the carriage transport for which the stop finger is entirely in the frontal outer zone with respect to the vertical folding plane, the rear half of it with the ball screw protrudes from the side and others of the vertical faces of the guide carriage, faces parallel to the folding plane.

We can easily understand that thanks to this design the stop fingers are motorized individually in their movements perpendicular to the fold plane and can be brought entirely out of the folding press into the outside area front of it. In this position, the stop fingers can be replaced or adjusted safely and can even be used to move the guide carriage to a new position relative to its support rail.

According to a preferred embodiment of the invention, each stop finger is mounted on a finger holder, the means for securing the finger holder at the front end of the carriage transport comprise means forming a pivot axis for said finger holder relative to said transport carriage, said axis of pivoting extending in a direction orthogonal to that of displacement of said transport carriage.

Preferably also, said means of securing of the finger holder comprise means for locking said finger holder on the front end of said transport cart, said means being able to be unlocked under the effect of a excessive stress applied to said finger.

More preferably, said means of securing include two coaxial pins arranged along said axis of pivoting of which one end is engaged in a bore of the finger holder and the second end of which is engaged in a bore of the front end of the carriage, said second end of the pins being chamfered, part of the chamfered end being engaged in the bore of the front end of said transport carriage and held in this position by a return spring, whereby under the effect of excessive stress applied to said finger, the springs of booster are compressed and allow the second ends of said pins to exit from said bores thus authorizing separation said finger holder relative to said transport trolley.

la figure 1 est une vue schématique partielle en élévation d'une coupe transversale verticale à travers une presse plieuse munie d'un dispositif mobile de doigt de butée ;

la figure 2 est une vue en plan d'un dispositif mobile de doigt de butée en position extrême avancée ;

la figure 2A est une vue en coupe selon la ligne A-A de la figure 2 ;

la figure 3 est une vue verticale en coupe du dispositif mobile de doigt de butée suivant la ligne III-III de la figure 2 ;

la figure 4 est une vue latérale en élévation du dispositif mobile de butée ; et

la figure 5 est une vue latérale similaire à celle de la figure 4, mais montrant le dispositif en position reculée dans laquelle l'extrémité frontale du doigt de butée se trouve dans la zone intérieure de la presse de pliage.

Other characteristics of the invention will emerge from the description of an embodiment given by way of nonlimiting example, this description being made with reference to the appended drawings in which

Figure 1 is a partial schematic elevational view of a vertical cross section through a press brake provided with a movable stop finger device;

FIG. 2 is a plan view of a mobile stop finger device in the extreme advanced position;

Figure 2A is a sectional view along line AA of Figure 2;

Figure 3 is a vertical sectional view of the movable stop finger device along line III-III of Figure 2;

Figure 4 is a side elevational view of the movable stop device; and

Figure 5 is a side view similar to that of Figure 4, but showing the device in the retracted position in which the front end of the abutment finger is in the inner area of the folding press.

In Figure 1 is shown schematically a cheek vertical lateral 1 of a frame in the form of a swan neck comprising front side a fixed lower deck 2, the upper side of which serves support to a folding die 3, as well as an upper deck (not shown) vertically movable in alignment with the deck lower 2 and carrying by its lower part one or more tools folding cooperating with said matrix 3.

The lower and upper aprons 2 with their respective matrix 3 and their folding tools define a vertical plane called folding 4 separating an interior area of press brake 5 from an area front exterior 6 in which the operator of the press brake can work without risk of personal injury.

The stop finger device 7 is normally arranged in the interior area 5 of the press brake between the side cheeks of the frame and behind the folding plane 4.

This device 7 comprises a support rail 8 which extends horizontally and parallel to the matrix 3 and to the vertical plane of folding 4. The support rail 8 can occupy a fixed position in relates to its distance from the vertical folding plane 4, this distance being such that in the retracted position of the stop finger 9 the front end of the latter is in the inner zone of the press brake and is close to folding plane 4, but does not exceed this one. The support rail 8 can if necessary be movable in the vertical direction to adapt to the height of the folding die 3. It could also be movable in a direction perpendicular to the folding plane 4 to allow the stop fingers 9 to take different distances from said plane 4.

Each stop finger 9 is associated with a carriage 10 which is slidably mounted on the support rail 8 with respect to which it can be locked in a chosen position after being moved there parallel to the folding die 3. The first carriage 10 of guidance not only allows the fingers 9 to move along the support rail 8 but also serves as a support and guide for a transport carriage 11 movably mounted on the guide carriage 10 of so that you can move horizontally and perpendicular to the folding plane 4. The transport carriage 11 is guided by two guides side 12, 13 of the guide carriage 10, these side guides 12, 13 being arranged on the upper face of the guide carriage 10 and extending horizontally and perpendicular to the vertical plane of folding 4.

The rear end of the stop finger 9 is carried by the front part of the transport carriage 11 whose length and stroke take into account the position of the support rail 8 and the guide carriage 10 associated with it so that, on the one hand, in end position before said transport carriage 11, the finger stop 9 and the front part of said carriage are located beyond the plane vertical folding 4, entirely in the front external zone 6 and that, on the other hand, at the end of the rear stroke, said transport carriage 11 and the front end of the stop finger 9 are entirely in the inner zone 5 of the press brake 1.

It will be noted that the length of the transport carriage 11 is at least twice the width of the guide carriage 10, width taken lengthwise of said transport cart 11. For for reasons of balance, it is however desirable that this length does not exceed three times the width of the guide carriage 10.

At its rear end, the transport carriage 11 comprises a transverse partition 14 on which is fixed the casing of an engine drive 15 whose output shaft is connected by a coupling 16 at the rear end of a mechanism drive 17 comprising a ball endless screw 17a and a nut 17b which cooperates with said ball screw 17a. The nut 17b is rendered immobile in rotation and in translation relative to the screw balls 17a using a vertical flange 18 fixed at the same time to the nut 17b and on side 10a of the guide carriage 10, side 10a diverted from the plane folding 4.

The flange 18 passes through an oblong recess 19 formed in the bottom of the transport carriage 11 over the entire active length of the screw ball 17a which extends perpendicular to the vertical plane of folding 4. The ball screw 17a is arranged in the rear part of the transport carriage 11, this rear part being slightly more as long as the rear half of said carriage 11. The ends of the screw balls are housed in rolling bearings 20, 21 which prevent said screw 17a to move axially and which are integral with the transport cart 11 and lean against the ends of two stiffening ribs 22, 23 provided on either side of the oblong recess 19 of the carriage 11.

As can be seen in the drawings, the rear part of the transport carriage 11, part comprising the ball screw 17a, covers the guide carriage 10 entirely, when said carriage transport 11 is in the advanced position in which at least the stop finger 9 is located entirely and preferably also the part front of said carriage 11 in the front external zone 6 in front of the plane vertical folding 4. By cons, in the retracted position of the carriage transport 11, it is its front part which covers the guide carriage 10 and its rear part is cantilevered with respect to the latter, the tilting of the transport carriage 11 being prevented by the guides sides 12, 13 of the guide carriage 10. In this remote position of the transport carriage 11, the stop finger 9, including its end front, is in the inner area 5 of the press brake 1.

At its front end, the transport carriage 11 includes a notch 24 in which is housed the rear tail 25 of a finger holder 26, the front end of which is also provided of a recess 27 receiving the rear tail of the stop finger 9 biased against the domed heads of two support screws 40a and 40b engaged in the finger holder 26 by means of a tensioning screw 28 whose head rests against the bottom of an oblong hole 29 formed in the tail 25 of the finger holder 26.

The rear end of the tail 25 of the finger holder 26 is articulated by an axis 30 on the lateral arms of the notch 24, the bottom is bevelled so that said tail 25 can escape upwards by tilting around axis 30 clockwise of a watch.

Preferably, as shown in FIG. 2A, the axis 30, which is orthogonal to the direction of movement of the carriage 11, is produced by two pawns 41a and 41b. The first end 42 of each pawn is engaged in a bore 43 formed in the tail 25 of the finger holder 26. The other end 44 of each piece is chamfered. This second chamfered end 44 partially penetrates a bore 45 made in the arms 46 and 47 of the front end of the carriage 11, arms which are defined by the notch 24. The second end 44 of pins 41a and 41b is kept partially engaged in the bores 45 by return means 48 made up of preferably with Belleville washers.

We understand that thus the pawns 41a and 41b fill a double function: on the one hand, they constitute the pivot axis 30 of the stop finger 9 relative to the carriage 11, on the other hand, they form a finger holder 26 locking system on the front end (arms 46 and 47) of the transport carriage 11, this system being able to be unlocked due to excessive finger stress 9. Indeed, in this case, the return means 48 are compressed by such that the chamfered ends 44 of the pins 41a and 41b come out of the bores 45, thus freeing the finger holder 26 and therefore the finger 9.

The function of pivoting the finger around the axis 30 allows it to follow the vertical movement of the edge of the sheet applied against the finger under the effect of the folding action applied to the sheet metal by the cooperation of the fixed folding Vee and the punch. Without this possibility of pivoting, the stop finger 9 would introduce into the sheet parasitic stress during the folding operation.

The unlocking function makes it possible to avoid that in the event of wrong maneuvers, excessive constraints are applied to the various parts of the guide carriage and the transfer carriage.

Finally, it should be noted that, preferably, the carriage transfer 11 comprises a part 50 forming a stop face additional 51 being added to the abutment faces constituted by the terminal end 52 of finger 9 and by the shoulder 53 of this same finger. The additional abutment face 51 makes it possible to process sheets for which the distance between the edge in contact with the stop face and the fold line is greater than the maximum distance between the stop finger 9 itself in the maximum retracted position and the V folding.

Claims (4)

Press brake for sheets, provided with a movable device of stop fingers, said press comprising a frame (1) in the form of a swan neck having on the front side a fixed lower deck (2) whose upper face serves as a support for a folding die (3) and a vertically movable upper deck in alignment with the lower deck and carrying by its lower part one or more folding tools cooperating with said die (3) and located in a vertical plane (4) separating an interior zone (5) of the press brake of an external or frontal area (6) in which the operator of the press brake can work without danger of accident, while the mobile device of stop fingers (7) comprises a rail support (8) which is arranged in the interior area (5) of the press brake, extends parallel to the folding die (3) and is movable at least vertically, a support (10) for each stop finger (9 ) resting on said rail (8) and mounted movably on the latter parallel to said die (3) as well as a carriage (11) capable of moving the stop fingers (9) at least partially outside the interior area (5) of the press brake ( 1) towards the front external zone (6) thereof, characterized in that the support rail (8) is mounted in the internal zone (5) of the press brake (1) at a determined distance from the vertical plane of folding (4), that a guide carriage (10) provided with locking means is capable of sliding along the support rail (8) and has on its upper face two lateral guides (12, 13) extending perpendicularly in the folding plane (4), that a transport carriage (11) is mounted on the guide carriage (10) and is guided by the lateral guides (12, 13) of the latter (10) in its forward movements back and forth perpendicular to said folding plane (4), that the transport carriage (11) has a longitudinal extension greater than the width d u guide carriage (10) and carries at its front end situated on the side of the folding plane (4) a removable stop finger (9) and at its rear end the casing of a drive motor (15), which 'a drive (17) worm (17a) and nut (17b) is mounted on the rear half of the transport carriage (11) via bearings (20, 21) integral with said transport carriage (11 ) and receiving the ends of said ball screw (17a), that the rear end of said ball screw (17a) which extends perpendicular to the bending plane (4) is coupled to the output shaft of the motor d 'drive (15), and that the nut (17b) cooperating with the ball screw (17a) is fixed on the guide carriage (10) on the side diverted from the folding plane (4) via a flange (18) which passes through an oblong recess (19) formed in the bottom of the transport carriage (11) over the entire active length of the ball screw (17a) and that advanced position of the transport carriage (11) for which the stop finger (9) is entirely in the front external zone (6) relative to the vertical folding plane (4), the rear half thereof comprising the screw ball (17a) protrudes on either side of the vertical faces of the guide carriage (10), faces parallel to the folding plane. Press brake according to claim 1, characterized in that each stop finger (9) is mounted on a finger holder (26) and in that the means for securing the finger holder (26) to the front end of the carriage transport (11) comprise means (30) forming a pivot axis for said finger holder relative to said transport carriage, said pivot axis extending in a direction orthogonal to that of movement of said transport carriage (11) . Press brake according to claim 2, characterized in that said means for securing the finger holder (26) comprise means for locking said finger holder on the front end of said transport carriage (11), said locking means being suitable to be unlocked under the effect of excessive stress applied to said finger (9). Press brake according to claim 3, characterized in that said securing means comprise two coaxial pins (41a, 41b) arranged along said pivot axis, one end of which is engaged in a bore of the finger holder and the second end of which is engaged in a bore in the front end of the carriage, said second end of the pins being chamfered, a part of the chamfered end being engaged in the bore of the front end of said transport carriage and held in this position by a return spring , whereby under the effect of an excessive stress applied to said finger (9), the return springs are compressed and allow the second ends of said pins (41a, 41b) to come out of said bores thus allowing the separation of said finger holder ( 26) relative to said transport carriage (11).

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