DE69823773T2 - Method and machine for automatic bending of sheet metal parts - Google Patents

Description

AREA OF INVENTION

The The present invention relates to the bending of metal sheets by a bending press with a reciprocal bending form and relates in particular to a method of a device for automatic Bending metal sheets according to the preambles of claims 1, 4 or 5, which have versatile applications, in particular for automatic Bending thin Metal sheets, where possible is a number of bends on the same sheet in extremely short To execute time intervals; Dead times with conventional Bending presses by picking up a metal sheet and dispensing of the sheet occur after bending, thereby avoided.

STATE OF TECHNOLOGY

devices for automatic bending of sheet metal material performed by a robot, d. H. Bending presses, are used in several designs and are in earlier Documents have been proposed, for. In US-A-4,594,870, EP-A-0 555,908 and EP-A-0 742 054.

All These automatic bending devices generally see use a single robot or an automatic device before the respectively picking up a sheet, bending and delivering the sheet to perform the same bent piece, wherein all bending works during a work cycle in a single phase with the help of a single Robot or manipulator are executed.

Z. For example, in EP-A-0 472 054 of the applicant, the use of a Cartesian robot excited, the several driven axles to control a bending press; with the help of a special Calculation algorithm, the gripping element of the robot can the sheet during the Bending work to follow, where continuously the position of gripping elements as a function of the movement of a formula element of the same press brake is controlled continuously by a corresponding sensor is detected.

however can with the robots or devices according to the prior art only Sheets are processed with correspondingly high weight and large dimensions, with a limit for small ones Sheets, z. B. with dimensions of a few hundred millimeters or little bigger, up to workpieces, which have a gripping edge of about 50 mm is reached.

Therefore Usually, manual work is done when bending sheet metal of small size required, allowing the use of a conventional robot or an automatic bending device with regard to the whole Working cycle is not beneficial. In fact, the works needed to be managed of the workpiece, in particular for receiving the metal sheet and releasing it bent workpiece, a comparatively longer one Time than the ones to run the Bending work needed becomes, with the result of long Totzei th for the press in the recording a new metal sheet and the delivery of the bent workpiece.

The US-A-5,345,806 presents the closest the technique according to independent claim 5; in the US-A-5,345,806 uses two different manipulators, have different levels of function. All bending work are executed by the main manipulator; they are not separate and integrated bending work by the main and auxiliary manipulators according to US-A-5,345,806 possible.

TASKS OF INVENTION

Specific Research showed that it is necessary to have a very broadband Market requirement for bending workpieces with small dimensions to fulfill, what used to be considered only a little was to specify and automatic bending devices that provide a strong economic Alternative to the manual work with a bending press and a represent conventional robot.

Therefore It is a general object of the present invention to provide a device for automatic bending of sheet metal or in general sheet metal indicate that the above requirements are met can.

A Another object of the present invention is a method for automatically bending sheet material by means of a device specify with which each type of press can be easily controlled, so that the handling of the workpieces in a covering manner and without Dead working hours for the press can be made so that the work for picking up a workpiece to be bent and for dispensing the bent workpiece in the same bending cycle that the press is operating.

SHORT DESCRIPTION THE INVENTION

The above objects can be achieved by means of a method for automatically bending a sheet material according to claims 1 and 4 or for an automatic device according to the Claim 5 are solved.

According to the invention the device has first and second independent manipulators, e.g. B. anthropomorphic robots that move along a linear path each robot having an articulated arm with a gripping element comprising a number of axes of rotation and control means defined, which allow each of the two manipulators, independent along each other the movement path parallel to the front of the press move and the different movements of a metal sheet while to follow the bending work, then the steps of the whole Execute the duty cycle, the split between the two manipulators and executed one after the other.

As mentioned above, is when bending panels or metal sheets with small dimensions the Time to pick up a metal sheet and to give the bent one workpiece essentially equal to the time of the effective duty cycle for the small-sized ones Sheets, whereby the time to pick up a sheet and to release the bent workpiece is substantially equal to the effective duty cycle of the press, and also in the light of the fact that only a few bending work usually be carried out on sheets with small dimensions.

thanks the use of two independent and selectively operated manipulators with integrated work cycles, the suitable over a single press brake is controlled, the time to record and for dispensing a workpiece hidden, so that the bending press always in a bending readiness is held; Dead times are avoided.

According to one Feature of the present invention is the cycle for bending a Sheets are executed as a single work between two manipulators divided or executed sequentially by the manipulators, so that when the first manipulator receives a sheet and a Performs bending work, z. B. a first of two bending work, the second manipulator the already bent workpiece releases and takes a stand-by condition; after that, the first one gives Manipulator free the partially curved sheet metal between the Forms of the press is clamped, after which the second manipulator the workpiece takes over and the bending work completed.

As soon as the bending work is finished and the second manipulator is the curved one workpiece unloads, has the first manipulator has already taken a new metal sheet, to start a new bending cycle. In short, takes after one Aspect of the present invention, a manipulator a new bend Sheet metal on or unloads an already bent workpiece, while the other manipulator already performs the same bending work.

Of the Advantage according to The present invention resides in the fact that it is possible to in the work cycle of the press, the handling steps for picking up and releasing the workpieces to mask, thanks to the alternating combined use of the two manipulators working with the cycle of the press brake are coordinated.

The Device according to the invention is complete independently on the type of machine used for the bending work is to be used, and that of either one manual or automatic type, allowing a high flexibility in operation can be achieved.

According to one another embodiment the invention it is possible to use two robotic arms, so that two separate metal sheets can be bent at the same time and symmetrical workpieces can be made perfectly.

This can be achieved in that at the start of the first manipulator this receives a metal sheet and takes over the first half of the bending work. At this point, the first manipulator, similar to the one mentioned above, gives the partially bent workpiece free, which was sandwiched between the forms of the press to pick up new sheet metal while the second manipulator the first sheet, which is already partially bent, sandwiched between the two forms of press picks. The bending work of the first sheet by the second manipulator can therefore simultaneously with the beginning of the bending work for the new sheet metal by the first manipulator to be completed. In practice, the lead Manipulators perform the same bending work, at the same time two different sheets in different working positions the same press.

SHORT DESCRIPTION THE DRAWINGS

These and further features of the invention will become apparent from the following description of exemplary embodiments with reference to the drawing, in the:

1 a view of an apparatus for automatically bending metal sheets according to the invention;

2 a top view of the device according to 1 is;

3 a side view of the device according to 1 is;

4 is a block diagram, the control circuit for the device according to 1 shows;

5 to 10 schematically illustrate the operations of a bending cycle, which are performed by the method and by the device for automatic bending according to the invention.

DETAILED DESCRIPTION OF THE INVENTION

As in the 1 to 3 illustrated, the device comprises a bending press 10 and a robot device 11 to pick up and manipulate metal sheets to be bent according to a programmed bending scheme.

The bending press 10 may be of any conventional type and z. B. have a hydraulic press, a frame structure 12 having a lower mold element 13 and an upper mold element 14 which supports vertically with respect to the solid form element 13 z. B. by means of a pair of hydraulic cylinders 15 is movable.

In the case shown, the press 10 an upper movable mold element; However, it is possible that the press has a lower movable mold element, or that both mold elements are movable relative to each other.

The reference number 16 in 3 denotes a front sensor for the positioning of a metal sheet between the form elements of the press, which, together with side sensors, provides control signals indicating the presence and the correct positioning of the metal sheet between the mold elements 13 and 14 specify. In this way, a control signal for starting each bending operation is provided as explained below.

The reference number 17 in 3 Finally, a signal generator of the linear and absolute type, directly or indirectly with the movable mold element 14 is coupled to provide reference signals that the achieved positions by the same movable mold element 14 during its forward movement towards the lower mold element 13 in order to allow a correct execution of each bending operation of a sheet.

According to the invention, the robot device 11 for receiving and manipulating metal sheets to be bent in a bending press, a base frame 18 for supporting a first manipulator or robotic arm 19 and a second manipulator 20 auf, which is designed as a twin, ie, in total identical to the preceding one.

The manipulators 19 and 20 can be parallel to the front of the press brake 10 on a pair of rails or guides 21 slide or move, which are parallel above the longitudinal sides of the support base 18 extend. The support base 18 is with swivel or sliding wheels 22 provided a movement and a correct positioning with respect to the press 10 allow.

A bridge frame 23 extends from the base 18 upwards and supports electronic equipment to control the two manipulators 19 and 20 their operation to the press 10 is forwarded in the manner described below.

Every manipulator, z. B. the manipulator 19 , each has a base body 24 on, with wheels or rollers 25 is provided, extending along the guides 21 move. The lateral movement of each Manipu lators 19 and 20 can be achieved by suitable drive means, for. B. by a hydraulic, pneumatic or electric drive. In the present case is an electric motor 26 for a pair of gears 27 provided, each in a toothed belt 28 intervene between two cross elements 29 at the ends of the support base 18 is curious.

Every manipulator 19 and 20 each has an articulated arm 30 on that with a gripping element 31 is provided, which can be moved in four polar axes of rotation. In particular, the swivel arm 30 a first arm part 30A on, around a horizontal axis 32 controlled by a first drive motor 33 , can turn.

The articulated arm 30 has a second arm part 30B on that around a second horizontal axis 34 parallel to the previous one under control of a second drive motor 35 can turn.

The gripping element 31 is in turn with two drive motors 31 ' and 31 '' and can rotate about two mutually orthogonal axes, one of which is parallel to the axes 32 to 34 and the other longitudinal to the same gripping element 31 runs. The various motors for driving the two manipulators are equipped with appropriate encoders or signal generators that provide reference signals that provide information about the exact positioning of the gripping element at all times 31 in the room.

Finally, the reference numeral designates 36 in 2 the position for loading or recording the metal sheets to be bent, whereas 37 denotes the unloading or discharging position for the bent pieces.

The working area of the two manipulators 19 and 20 Can along one side and on both sides of the support base 18 lie, so physically the articulated arm 30 each manipulator can pick and drop the metal sheets along the press, or it can cover an area on the back of the base 18 by simply turning in a vertical plane of the articulated arm. The manipulators 19 and 20 can therefore work easily on the front and on the back according to the space available.

4 The accompanying drawing shows schematically the electronic device for the control and tracking of the two manipulators 19 and 20 with regard to the bending press 10 ,

As schematically in 4 indicated, the electronic control unit has a microprocessor 40 with a volatile memory on, for. B. a RAM, wherein a program for controlling and tracking the two manipulators 19 and 20 is stored with respect to the movements of the movable mold elements. The control is carried out by means of the position signals supplied to the microprocessor 40 through the sensor 17 through a digital / analog converter 41 be supplied.

Program and computing means are also provided which provide a suitable algorithm or mathematical formulas for computing the coordinates of the translational and rotational movements of the gripping element 31 of each manipulator in accordance with the movement of the metal sheet during bending in the press. The algorithm is in a permanent memory 42 , z. B. an EPROM stored with the microprocessor 40 over the bus 43 connected is. The reference number 44 indicates another programmable and erasable memory, e.g. As an EEPROM, in the various calculation data programmed and / or stored, such. B. the maximum width of the bending cavity of the mold element 13 and the zero point on the Z-axis of the movable element 14 on the basis of which the microprocessor determines the motion coordinates of the gripping element 31 calculated for the metal sheets to be bent. All this is known and detailed in the above-mentioned application EP-A-0 742 054.

Finally, designate 45 and 46 in 4 the internal CPU, which selectively controls the movements of each of the two manipulators 19 and 20 controls.

Based on 5 to 10 Now, the working mode of the entire apparatus and the fundamental steps of the process of automatically bending metal sheets according to the invention will be described.

As previously mentioned, the device has a bending press 10 and a robot device 11 for receiving and manipulating metal sheets to be bent, which are fed to the press.

The robot device is, as previously mentioned, by two independent manipulators or robots 19 and 20 formed between which the entire bending cycle of a sheet is divided so that the first manipulator 19 a metal sheet 50 from a pile in the loading position 36 at one end of the support and leadership structure 18 whereas the other manipulator 20 is stationary and directed against the press in a stand-by or stand-by position ( 5 ).

As soon as the first manipulator 19 a metal sheet has been added, becomes his articulated arm 30 forward against the press 10 rotated and is in a working position according 6 in which he made a first part of the work cycle for bending the previously recorded and correct between the form elements of the press 10 of the metal sheet 5 with control of the microprocessor 40 as a function of the control signals generated by the position sensor or sensors 16 and 17 were delivered. During this step, the second manipulator remains in the aforementioned waiting position.

After completion of the first bending steps for the sheet 50 with the help of the first manipulator 19 this gives the partially bent sheet metal 50 free, which is between the closed form elements 13 and 14 the press remains clamped. Now the second manipulator is moving 20 in the direction of the bent and clamped between the bending mold elements metal sheet, and in the short moment in which the partially bent sheet is clamped by the second manipulator, the first manipulator moves 19 turn left ( 7 ) in the receiving position to a new sheet metal 51 while the second manipulator 20 who was already on standby, to the press 10 is guided and his swivel arm against the already partially bent metal sheet 15 moves it with its gripping element in the correct position, after which this manipulator 20 returns to the previous working position ( 8th ), in which he the bending cycle of the metal sheet 50 completed as a function of the programmed work program.

In the meantime, the first manipulator has 19 already from the stack the new sheet metal to be bent 21 recorded and assumes a waiting or standby position.

After completion of the bending cycle of the first sheet 50 the manipulator moves 20 completely right in 9 where he has his bending arm on the back 30 turns around the curved metal sheet or part 50 release and in the unloading zone 37 to deposit. In the meantime, the first manipulator 19 turn to the press 10 led to the new sheet metal 51 between the form elements 13 and 14 to position the press and in turn to perform a first part of the work cycle for the new sheet, while the previously finished part through the second manipulator in the unloading zone 37 is filed.

The working cycle of the entire apparatus can then be cyclically repeated and continued in the manner described above. The great advantage of the device and the method according to the invention is therefore with the alternative application of the two manipulators 19 and 20 by sequentially performing two different bending cycles on the same metal sheet and performing the picking up and releasing of a metal sheet or bent part by one of the two manipulators while the other is working; this allows an overlap of the so-called action steps on the sheet, ie, receiving a sheet to be bent and releasing and depositing a bent piece, whereby the working hours are drastically reduced, especially for small metal sheets.

As regards programming, as mentioned above, the method is the same as that described for the apparatus in the aforementioned European Patent Application EP-A-0 742 054, to which reference is made, with the sole difference that now the bending program is divided into two separate parts, each one of the two manipulators 19 respectively. 20 be assigned.

The Device described here can be used for both asymmetric bending as well as symmetrical parts.

In in the latter case the two manipulators can be used simultaneously to work together to carry out the two separate parts of the bending cycle on separate sheets.

In this regard, at the start of each cycle takes the first manipulator 19 a metal sheet from the stack in the zone 36 on and performs the first half of the bends on the sheet metal. Thereafter, as in the previous bending cycle, the manipulator releases the partially bent and clamped sheet in the press to receive a new sheet. In the meantime, the second manipulator moves into position, picking up the first partially bent sheet still clamped between the mold members of the press, and completes the bending work. Given symmetry of the part to be machined, this latter operation can be done simultaneously with the bending of the new latter operation simultaneously with the bending of the new metal sheet picked up by the first manipulator.

In practice, the two manipulators perform 19 and 20 simultaneously perform the same bending work on two sheets in two different working positions of the same press.

Out Is represented in what has been said and in the accompanying drawings it is therefore clear that the device for automatic bending of Metal sheets make it possible perform an entire bending cycle sequentially on a same sheet, wherein the dead times of the press, which are usually for the work to pick up a sheet and release and discard a bent sheet, totally eliminated are what's running now will, while one of the two manipulators works and part of the bending cycle on a sheet metal performs.

It However, it is clear that what has been said and in the adjacent figures Shown only an example of the general features of Apparatus and method according to the invention; therefore are changes or variants possible, without thereby affecting the present invention, as set forth in the appended claims claims is defined, is left.

Claims (9)

Method for performing automatic bending work on a metal sheet to form a bent piece by means of a press ( 10 ) and by a first ( 19 ) and second ( 20 ) Manipulator connected to the press ( 10 ), with the steps of: a) picking up a first sheet ( 50 ) in a loading zone ( 36 ) by the first ( 19 ) of the manipulators ( 19 . 20 ); b) forming a first set of bends on the first metal sheet ( 50 ) during a first step of the bending cycle, wherein the metal sheet under controlled conditions by the first manipulator ( 19 ) and the second manipulator ( 20 ) is kept on stand-by; c) clamping the partially bent sheet between form elements ( 13 . 14 ) the press ( 10 ) at the end of step b) and releasing the metal sheet ( 50 ) by the first manipulator ( 19 ); d) picking up the partially bent metal sheet ( 50 ) by the second manipulator ( 20 ), while the same sheet ( 50 ) firmly between the form elements ( 13 . 14 ) of the bending press ( 10 ), characterized by the steps: e) completing the bending cycle for this first sheet by applying a second set of bends with the aid of the second manipulator ( 20 ) is performed to obtain a bent piece; and f) releasing the bent piece ( 50 ) by the second manipulator ( 20 ) at the end of step e) and placing this piece ( 50 ) in an unloading zone ( 37 ). Method according to claim 1, characterized by the additional step of receiving a further metal sheet ( 51 ) with the aid of the first manipulator ( 19 ) while the second manipulator ( 20 ) the first between the features ( 13 . 14 ) receives the clamped first sheet of the press; and performing a set of bends on the further metal sheet according to steps b) to f) of the first metal sheet ( 50 ). Method according to claim 1, characterized by the additional step of receiving a further metal sheet ( 51 ) with the aid of the first manipulator ( 19 ) while the second manipulator ( 20 ) executes the second set of bending steps after step e), and executes a set of bends on the further metal sheet ( 51 ) according to steps b) to f) for the first metal sheet ( 50 ). Method for performing automatic bending work on a metal sheet to form a bent piece on a press ( 10 ), this sheet being replaced by a first ( 19 ) and a second ( 20 ) Manipulator is moved with the press ( 10 ), in particular for bending symmetrical pieces, comprising the steps of: i) picking up a first metal sheet ( 50 ) by the first ( 19 ) of the manipulators ( 19 . 20 ); ii) performing a first set of bending operations on the first metal sheet ( 50 ), this metal sheet ( 50 ) between form elements ( 13 . 14 ) the press ( 10 ) by the first manipulator ( 19 ) is held and moved; iii) pinching the partially bent first sheet ( 50 ) between the features ( 13 . 14 ) the press ( 10 ) at the end of step ii), releasing the partially bent first sheet ( 50 ) by the first manipulator ( 19 ); iv) receiving the first partially bent sheet by the second manipulator ( 20 ), while the same first sheet tightly between the mold elements ( 13 . 14 ) is held; v) picking up another metal sheet ( 51 ) by the first manipulator ( 19 characterized by the steps of: vi) co-bending the first metal sheet ( 50 ) and the further metal sheet ( 51 ), which by the first ( 19 ) or second ( 20 ) Manipulator, performing the first set of the bending work on the further metal sheet ( 51 ) and ending the bending cycle by carrying out a second set of bending operations on the first metal sheet ( 50 ) corresponding to the first, on the first metal sheet ( 50 ) carried out bending work. Device for automatically bending metal sheets ( 50 ) to form a bent piece, comprising: - a bending press ( 10 ), the upper and lower with respect to each other movably supported form elements ( 13 . 14 ) to a metal sheet positioned therebetween ( 50 ) to bend; and - actuator devices ( 15 ) for reciprocating at least one ( 14 ) of the form elements ( 13 . 14 ); A robot device ( 11 ) for receiving and positioning the metal sheet between the mold elements ( 13 . 14 ) the press ( 10 ) for bending, the robot device ( 11 ): - a support structure with a base region ( 18 ), with guided tours ( 21 ) in the longitudinal direction and parallel to a front side of the bending press ( 10 ) extend; A first and a second manipulator ( 19 . 20 ) along the guides ( 21 ) are movable, each manipulator ( 19 . 20 ) an articulated arm ( 30 ) with a handle element ( 31 ) for holding the metal sheet ( 50 ) having; - programmable control devices ( 40 - 46 ), these programmable controllers ( 40 - 46 ) selectively manipulators ( 19 . 20 ), so that these a metal sheet ( 50 ) and sequentially bending work on this metal sheet ( 50 ), characterized in that the programmable controllers ( 40 - 46 ) a programmable control unit (CPU) for each manipulator ( 19 . 20 ), wherein - the control unit (CPU) for the first manipulator ( 19 ) to allow this manipulator to perform a first set of bending operations on the metal sheet ( 50 ) and the partially bent and in the bending press ( 10 ) clamped metal sheet ( 50 ) release; and - the control unit (CPU) for the second manipulator ( 20 ) so that the same manipulator can sequentially grasp the partially bent sheet metal clamped in the bending press and perform a second set of bending operations on this partially bent piece of metal while the first manipulator (FIG. 19 ) performs a first set of bending work on a new metal sheet. Apparatus according to claim 5, characterized in that the control unit (CPU) for the first manipulator ( 19 ) is programmed to pass through the first manipulator ( 19 ) a first set of bending work on a metal sheet ( 50 ), and that the control unit (CPU) for the second manipulator ( 20 ) is programmed to pass through this second manipulator ( 20 ) to carry out a second set of bending work, which differs from the set of bending works, that of the first one Manipulator ( 19 ) of the robot device ( 11 ). Apparatus according to claim 5, characterized in that the control device (CPU) for the first manipulator ( 19 ) is programmed to pass through this first manipulator ( 19 ) a first set of bending work on a metal sheet ( 50 ), and that the control unit (CPU) for the second manipulator ( 20 ) is programmed to pass through this second manipulator ( 20 ) to carry out a second set of bending operations corresponding to the set of bending operations performed by the first manipulator ( 19 ) of the robot device ( 11 ). Apparatus according to claim 7, characterized in that the control devices (CPU) for the manipulators ( 19 . 20 ) are programmed to the first and second set of bending work on different metal sheets and in different position of the mold elements ( 13 . 14 ) of the bending press ( 10 ) together. Device according to claim 5, characterized in that each manipulator comprises an articulated arm ( 30 ) and drive devices ( 40 - 46 ) to this arm ( 30 ) from a rearward position to a forward position of the support structure ( 23 ), which faces a front of the press ( 10 ) is opposite.