EP1264647B1 - Press brake for sheets with a movable workpiece stop device - Google Patents

Description

The present invention relates to a sheet metal press brake equipped with a mobile stop finger device, said press comprising a gooseneck-shaped frame having a fixed lower deck on the front side, the upper face of which serves as support for a matrix. bending and a vertically movable upper apron in alignment with the lower apron and carrying at its lower part one or more folding tools cooperating with said die and located in a vertical plane separating an inner zone of the press brake from an outer zone or in which the operator of the press brake can work without danger of accident, while the mobile device of stop fingers comprises a support rail which is arranged in the inner area of the press brake, extends parallel to the folding die and is moveable at least vertically, a support for each stop finger resting on said rail and mounted movably on the latter parallel to said matrix and a carriage capable of moving the stop fingers at least partially out of the inner zone of the press brake to the front outer zone thereof.

A plate press brake of the type comprising a mobile device of stop fingers is known by the request of 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 rails of a second movable carriage horizontally and perpendicular to the vertical plane passing through the folding die, the two carriages being arranged in the inner zone of the press brake.

A disadvantage of this arrangement lies in the fact that the stop finger holders can not leave the inner area of the press brake so that the replacement of a stop finger forces the operator to advance his hands in said inner area and place these between the tool and the folding die. Since, moreover, the stop fingers commonly used have the same length, they can not be adapted without the exchange of at least one stop finger with a sheet whose stop edge is cut into steps. or in another staged way. Yet another disadvantage of the movable stopper device is the necessity of moving the support rail whenever the positioning of the stop edge of the sheets is changed with respect to the folding die.

The object of the present invention is to overcome the above-mentioned known drawbacks and to propose, in association with a press brake, a mobile device of stop fingers allowing each stop finger to protrude entirely beyond the vertical plane containing the folding edge of the the folding die and being individually positioned at a distance from said vertical plane.

This object is achieved according to the invention in that the support rail is mounted in the inner zone of the press brake at a predetermined distance from the vertical plane of folding, that a guide carriage provided with locking means is capable of slide along the support rail and has at its upper side two lateral guides extending perpendicularly to the fold plane, a transport carriage is mounted on the guide carriage and is guided by the lateral guides of the latter in its reciprocating movements perpendicular to said folding plane, that the transport carriage has a longitudinal extension greater than the width of the guide carriage and carries at its end end located on the side of the folding plane a removable stop finger and to its rear end the crankcase of a drive motor, a worm drive is mounted on the rear half of the transport cart via palie secured to said transport carriage and receiving the ends of said ball screw, that the rear end of said ball screw which extends perpendicular to the fold plane is coupled to the output shaft of the drive motor, and that the nut cooperating with the ball screw is fixed on the guide carriage on the side diverted from the folding plane by means of a flange which passes through an oblong recess formed in the bottom of the transport carriage over the entire active length of the ball screw and that in the forward position of the transport carriage for which the stop finger is entirely in the frontal outer zone relative to the vertical plane of folding, the rear half thereof comprising the ball screw exceeds of share and others of the vertical faces of the guide carriage, faces parallel to the plane of folding.

It will be readily understood that with this design the stop fingers are motorized individually in their movements perpendicular to the bending plane and can be brought entirely out of the bending press in the frontal outer zone thereof. In this position, the stop fingers can be replaced or adjusted without danger and can even be used to move the carriage in 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 to the front end of the transport carriage comprise means forming a pivot axis for said finger holder with respect to said transport carriage, said pivot axis extending in a direction orthogonal to that of displacement of said transport carriage.

Also preferably, said means for securing the holder comprises locking means of said finger holder on the front end of said transport carriage, said locking means being able to be unlocked under the effect of excessive stress applied audit finger.

More preferably, said securing means comprise two coaxial pins arranged along said pivot axis, one end of which is engaged in a bore of the finger holder and whose second end is engaged in a bore of 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 carriage and held in this position by a return spring, whereby under the effect of undue stress applied to said finger, the return springs are compressed and allow the second ends of said pins to exit said bores and allowing the separation of said finger carrier relative to said transport carriage.

• 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 features of the invention will emerge from the description of an embodiment given by way of non-standard example. this description being made with reference to the appended drawings in which

• the figure 1 is a partial schematic view in elevation of a vertical cross section through a press brake provided with a movable stop finger device;
• the figure 2 is a plan view of a moving end stop finger device in the extreme forward position;
• the Figure 2A is a sectional view along line AA of the figure 2 ;
• the figure 3 is a vertical sectional view of the mobile stop finger device along line III-III of FIG. figure 2 ;
• the figure 4 is a side elevational view of the movable abutment device; and
• the figure 5 is a side view similar to that of the figure 4 but showing the device in the retracted position in which the end end of the stop finger is in the inner area of the folding press.

On the figure 1 is schematically represented a vertical side cheek 1 of a gooseneck-shaped frame having on the front side a fixed lower deck 2 whose upper face serves as a support for a folding die 3, and an upper deck (not shown vertically movable in alignment with the lower apron 2 and carrying at its lower part one or more folding tools cooperating with said die 3.

The lower and upper aprons 2 with respectively their matrix 3 and their folding tools define a so-called vertical plane of folding 4 separating an inner area of the press brake 5 from a frontal outer zone 6 in which the operator of the press brake can work without risk of bodily injury.

The stop finger device 7 is normally disposed in the inner zone 5 of the press brake between the lateral cheeks of the frame and behind the fold plane 4.

This device 7 comprises a support rail 8 which extends horizontally and parallel to the die 3 and to the vertical plane of folding 4. The support rail 8 can occupy a fixed position with respect to its distance from the vertical plane of folding 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 area of the press brake and is close to the fold plane 4, but does not exceed it. The support rail 8 can optionally 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 fold plane 4 to allow the stop fingers 9 to take different distances from this plan 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 selected position after being moved parallel to the folding die 3. The first carriage 10 not only allows the fingers 9 to move along the support rail 8 but also serves to support and guide a transport trolley 11 movably mounted on the trolley 10 so as to be able to move horizontally and perpendicular to the fold plane 4. The transport carriage 11 is guided by two lateral guides 12, 13 of the guide carriage 10, these lateral 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 portion of the transport carriage 11 whose length and the maximum stroke take into account the position of the support rail 8 and the associated guide carriage 10 so that, on the one hand, in end-of-travel position before said transport carriage 11, the stop finger 9 and the front part of said carriage are, beyond the vertical folding plane 4, entirely in the frontal outer 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 trolley 11 is at least twice the width of the trolley 10, a width taken along the length of said trolley 11. For reasons of balance, however, it is 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 housing of a drive motor 15 whose output shaft is connected by a coupling 16 to the rear end of a mechanism drive 17 comprising a ball screw 17a and a nut 17b which cooperates with said ball screw 17a. The nut 17b is rendered motionless in rotation and in translation relative to the ball screw 17a by means of a vertical flange 18 fixed at the same time to the nut 17b and on the side 10a of the guide carriage 10, side 10a diverted from the fold plane 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 ball screw 17a which extends perpendicular to the vertical plane of folding 4. The ball screw 17a is disposed in the part rear of the transport carriage 11, this rear portion being slightly longer than the rear half of said carriage 11. The ends of the ball screw are housed in rolling bearings 20, 21 which prevent said screw 17a from moving axially and which are integral with the transport carriage 11 and bear 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, completely covers the guide carriage 10, when said transport carriage 11 is in the advanced position in which at least the stop finger 9 is entirely and preferably also the front portion of said carriage 11 in the front outer zone 6 in front of the vertical plane of folding 4. On the other hand, in the retracted position of the transport carriage 11, it is its front part which covers the guide carriage 10 and its rear portion is cantilever with respect to the latter, the tilting of the transport carriage 11 being prevented by the lateral guides 12, 13 of the guide carriage 10. In this retracted position of the transport carriage 11, the stop finger 9, including its front end, is in the inner zone 5 of the press brake 1.

At its front end, the transport carriage 11 comprises a notch 24 in which the rear tail is housed. 25 of a finger holder 26 whose front end is also provided with a recess 27 receiving the rear tail of the stop finger 9 biased against the curved heads of two support screws 40a and 40b engaged in the finger holder 26 by means of a tensioning screw 28 whose head bears 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 whose bottom is beveled so that said tail 25 can escape upwards by tilting around of the axis 30 in the direction of clockwise.

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

It is thus understood that the pins 41a and 41b fulfill 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 locking system of the finger holder 26 on the front end (arms 46 and 47) of the transport carriage 11, this system being able to be unlocked under the effect of an excessive stress applied to the finger 9. In this case, the means 48 are compressed in such a way that the chamfered ends 44 of the pins 41a and 41b emerge from the bores 45, thus releasing the finger holder 26 and thus the finger 9.

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

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

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

Claims (4)

1. Press brake for sheet metal, provided with a mobile stap-pin device, said press comprising a swan-neck shaped frame (1) having on the front side a lower fixed apron (2), the upper face of which serves as a support for a bending die (3) and an upper, vertically mobile apron aligned with the lower apron and carrying, with its lower part, one or more bending tools co-operating with said die (3) and located in a vertical plane (4) separating an inner zone (5) of the press brake from an outer or front zone (6), in which the operator of the press brake can work without risk of accident, while the mobile stop-pin device (7) comprises a support rail (8) that is positioned in the inner zone (5) of the press brake, extends parallel to the bending die (3) and is mobile at least vertically, a support (10) for each stop-pin (9) resting on said rail (8) and mounted so as to be mobile on the latter, parallel to said die (3) as well as a carriage (11) capable of displacing the stop-pins (9) at least partly out of the inner zone (5) of the press brake (1) towards the front outer zone (6) thereof, characterised in that the support rail (8) is mounted in the inner zone (5) of the press brake (1) at a given distance from the vertical plane of bending (4), that a guide carriage (10) provided with locking means is capable of sliding along the support rail (8) and comprises at its upper face two side guides (12, 13) extending perpendicular to the plane of bending (4), that a transport carriage (11) is mounted on the guide carriage (10) and is guided by the side guides (12, 13) of the latter (10) in its to-and-fro movements perpendicular to said plane of bending (4), that the transport carriage (11) has a longitudinal extension greater than the width of the guide carriage (10) and carries at its front end located alongside the plane of bending (4) a removable stop-pin (9) and at its rear end the housing of a drive motor (15), that a drive (17) with 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 plane of bending (4), is coupled with the output shaft of the drive motor (15), and that the nut (17b) co-operating with the ball screw (17a) is fixed to the guide carriage (10) on the side facing away from the plane of bending (4) by means of a clamp (18) that passes through an oblong recess (19) made in the bottom of the transport carriage (11) over the entire active length of the ball screw (17a) and that, when the transport carriage (11) is in a forward position, for which the stop-pin (9) is located entirely in the front outer zone (6) relative to the vertical plane of bending (4), the rear half of said transport carriage, comprising the ball screw (17a), juts out on either side of the vertical faces of the guide carriage (10), which faces are parallel to the plane of bending.
2. Press brake according to Claim 1, characterised in that each stop-pin (9) is mounted on a pin-carrier (26) and in that the means for fixing the pin-carrier (26) to the front end of the transport carriage (11) comprise means (30) forming an axis of pivoting for said pin-carrier relative to said transport carriage, said axis of pivoting extending in a direction orthogonal to the direction of displacement of said transport carriage (11).
3. Press brake according to Claim 2, characterised in that said means for fixing the pin-carrier (26) comprise means for locking said pin-carrier to the front end of said transport carriage (11), said locking means being capable of being unlocked under the effect of excessive strain applied to said pin (9).
4. Press brake according to Claim 3, characterised in that said fixing means comprise two coaxial slugs (41a, 41b) positioned along said axis of pivoting, one end of which is engaged in a hole in the pin-carrier and the second end of which is engaged in a hole in the front end of the carriage, said second end of the slugs being chamfered, a part of the chamfered end being engaged in the hole in the front end of said transport carriage and held in this position by a return spring, by which, under the effect of excessive strain applied to said pin (9), the return springs are compressed and allow the second ends of said slugs (41a, 41b) to come out of said holes thus permitting said pin-carrier (26) to be unfixed from said transport carriage (11).

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