EP0529705A1

EP0529705A1 - Programmable machine for punching large sheet metal plates

Info

Publication number: EP0529705A1
Application number: EP92202336A
Authority: EP
Inventors: Guido Salvagnini
Original assignee: Salvagnini SpA
Current assignee: Salvagnini SpA
Priority date: 1991-08-30
Filing date: 1992-07-29
Publication date: 1993-03-03
Also published as: ITMI912334A0; JPH05200452A; IT1251197B; ITMI912334A1

Abstract

A machine (10) has been developed for punching sheet metal plates, comprising two rotating disks (15; 150, 18; 180) with horizontal axes one above the other suitable for housing at least one crown of punches (22) and at least one crown of matrices (38), respectively; the disks are operationally connected to corresponding motor means (40, 41) capable of having them execute pre-established angular displacements, suitable for positioning a pre-selected punch (22) and a corresponding matrix (38) in a pre-selected operating position; said machine also comprises a manipulator (60) provided with clamps (73) capable of grasping a sheet of metal plate, and with a control device (100) capable of avoiding interferences between the same clamps (73) and said punches (22).

Description

The present invention relates to a programmable machine for punching large sheet metal plates, having the possibility of meeting different punching requirements.
Machines for punching large sheet metal plates have a force structure substantially conformed in the shape of a swan neck, with an upper arm supporting a punch and a corresponding operating device, a lower arm supporting a matrix and defining a horizontal operating plane, on which the sheet metal plate to be punched is placed, and a throat that is as long as the width of the same sheet metal plate; a manipulator moves the sheet metal plate in the operating plane along two orthogonal axes, so that every point of the sheet itself can be punched according to a programmed operating plan.
For the punch to be programmed with sufficient freedom, the machines also include an automatic device for replacing the punch and the matrix in the respective operating positions.
Thus all known machines in this category have three essential mechanical parts: the swan neck structure with punch and matrix and the punch's operating device, that together constitute the press, the sheet metal plate's manipulator and the device for replacing the punch and the matrix.
These latter two parts are in competition with one another in occupying the free space in the throat of the press. In no known machine are both the manipulator and the tool-changing device inside this cavity: in some there is one, in others there is the other.
The one of the two that remains outside must be placed on an extension of the swan's nech lower arm. In some machines the upper arm is also extended and the two arms are joined at the extremity, and the swan neck structure is transformed into a portal-like structure.
In any case the size of the machine is greater than with the swan neck structure alone and often the installation of the machine at the location where it is to operate requires long operations because, for the convenience of building the structure, the support of the manipulator or of the tool-changing device is a distinct unit that must be fixed to the floor and aligned separately.
The manipulator of punching machines on the market today has a certain number of clamps, that grasp the sheet metal plate along one of the edges. The operator programming the machine must so arrange things that the clamps grasp the sheet in areas where no punch is to be executed, otherwise the punching tools would interfere with the clamps themselves. Very frequently this is not possible and several operations must be programmed on the sheet.
A first object of the present invention is that of applying both the manipulator and the tool-changing device directly on the swan neck structure, avoiding increases in size and difficulties of installation and so that the machine can be assembled completely by the manufacturer and then moved and installed without disassemblying and reassembling it.
A second object of the present invention is that of automatically avoiding the interference between the manipulator's clamps and the tools, so that the operator is free from any worry relating to this possibility.
According to these objects a machine has been developed capable of punching metal plates, particularly in large sheets, comprising a force structure substantially conformed in the shape of a swan neck defining a horizontal operating plane for a sheet of metal plate and provided with at least one punch operationally connected to an operating device, with at least one matrix and with a manipulator comprising in turn at least one carriage, slidably supported by said swan neck structure and that supports in an orthogonally slidable way at least one bar provided with clamps operationally connected to actuator means capable of operating them so as to grasp and release said sheet metal plate, said machine being characterized in that it comprises at least one first rotating disk provided at the periphery with at least one crown of radial seats, that house at least one crown of punches operationally connected to said operating device, and at least one second rotating disk provided at the periphery with at least one crown of radial seats that house at least one crown of matrices, said disks being rotatably supported by said swan neck structure by means of horizontal pivots having the axes one above the other and lying substantially in the vertical centre-line plane of the same swan neck structure, so that the same rotating disks are arranged complanar and one above the other, one upper and one lower, on the front of said swan neck structure, said disks being capable of being operated so that they can execute pre-established angular displacements for positioning a pre-selected punch and a corresponding matrix in a pre-established operating position, aligned with one another, with respect to said operating plane.
According to one possible embodiment said first rotating disk is provided at the periphery with two crowns of radial seats, that house two crowns of punches, and said second rotating disk is provided at the periphery with two crowns of radial seats for matrices, the punches of said two crowns being operationally connectable to said operating device by means of a tappet displaceable by a hydraulic or pneumatic actuator between a position of engagement with the punches of one crown and another position of engagement with the punches of the other crown.
According to another embodiment of the invention said manipulator comprises a control device for each clamp operationally connected to said actuator means and to means for detecting a pre-selected stop, said control means being capable of operating the same clamp to release said sheet when said stop is detected, each of said clamps being supported by said bar in a manner that is independently slidable in said sliding direction of the carriage, and being capable of engaging with a pre-selected limit stop, capable of preventing it from chasing said sheet metal plate, against the action of thrust means capable of keeping it up against another limit stop integral with said bar.
The proposed machine is an optimum solution as regards the problem of tool changes, size, transportability and installation on site; it also has a high degree of safety due to the presence of a control device, that in case of need opens one clamp and stops it before in interferes with the punching tool, allowing the other clamps to continue moving the sheet metal plate to be punched.
One possible embodiment of the present invention is illustrated, as a non-limiting example, in the enclosed drawings wherein:

Fig. 1 is a side view of a machine according to the invention;
Fig. 2 is a front view of the machine of Fig. 1;
Fig. 3 shows a vertical axial cross-section of an example of a punch-holding disk included in the machine of Fig.s 1 and 2;
Fig. 4 shows a variant of the punch-holding disk represented in Fig. 3;
Fig. 5 shows a further variant of the punch-holding disk represented in Fig. 3;
Fig. 6 shows a variant of the punch-holding disk represented in Fig. 5;
Fig. 7 is a partial cross-section taken along the line VII-VII of Fig. 6;
Fig. 8 shows a vertical axial cross-section of an example of a matrix-holding disk included in the machine of Fig.s 1 and 2;
Fig. 9 shows a variant of the matrix-holding disk represented in Fig. 8;
Fig. 10 is a plan view from above, on an enlarged scale, of a manipulator with clamps included in the machine of Fig.s 1 and 2;
Fig. 11 is a partial cross-section of the manipulator, in an enlarged scale, taken along the line XI-XI of Fig. 10;
Fig. 12 is a partial plan view of a detail of the manipulator of Fig. 11;
Fig. 13 is a diagrammatic representation of a hydraulic circuit of the machine of Fig.s 1 and 2.

There is shown as a whole in Fig.s 1 and 2 a programmable machine for punching large sheet metal plates, accomplished according to the invention.
There is indicated as a whole with 11 a swan neck structure, formed by an upper arm 12 and by a lower arm 13; the upper arm 12 is provided with a pivot 14 suitable for rotatably supporting, by means of ball-bearings 17, visible in Fig. 3, a rotating punch-holding disk, indicated as a whole with 15; the lower arm 13 is provided with a pivot 16 suitable for rotatably supporting, by means of ball-bearings 170, visible in Fig.s 8 and 9, a rotating matrix-holding disk, indicated as a whole with 18.
The pivots 14 and 16 of the two disks 15 and 18 are horizontal and have axes 19 and 20 that are complanar and one above the other, lying in a vertical centre-line plane, indicated with 10 in Fig. 2, and support the same disks in a manner complanar and one above the other, one upper 15 and one lower 18, on the front of the swan neck structure 11.
As shown in Fig. 3, the punch-holding disk 15 is provided, at the periphery, with a crown of radial cylindrical seats 21, suitable for housing a crown of punches 22, provided with shanks 23, on which there act holding springs 24 and with which a stem 25 of a hydraulically-operated twin-action piston 26 can engage, that, together with a cylinder 27 integral with the pivot 14, forms an operating device, indicated as a whole with 28; with the pivot 14 there is integral a partially-annular guide plate, indicated with 37.
In the variant of Fig. 4, the twin-action piston 26 of the operating device 28 is provided with a stem 29 with a T-shaped slot 30, by means of which it is capable of engaging, in push and pull, with the also T-shaped head 31 of the shank 23 of a punch 22, held in its seat 21 by a pawl 32.
In the variant of Fig.s 5 and 6 the punch-holding disk, indicated as a whole with 150, is, on the other hand, provided, at the periphery, with two crowns of radial cylindrical seats 21, suitable for housing two crowns of punches 22; in the embodiment of Fig. 5, the shank 23 of the punches 22 can, against the action of holding springs 24, engage with the stem 25 of the twin-action piston 26, through an elastically urged tappet, indicated as a whole with 33, displaceable by a hydraulically-operated piston 34, between two positions of engagement with the punches 22 of one or of the other crown; in the embodiment of Fig. 6 the stem 29 of the piston 26 has a T-shaped slot 30 that engages with the T-shaped head 35 of a tappet 330, operated by the piston 34; the tappet 330 is provided with a T-shaped slot 36 suitable for engaging with the T-shaped heads 31 of the shanks 23 of the punches 22 of one or of the other crown, as also shown in Fig. 7.
There is shown in Fig. 8 a matrix-holding disk 18, that, at the periphery, is provided with a crown of radial seats 280 for matrices 38, each corresponding to a punch 22 of the punch-holding disk 15. A passage 39 for discharging processing scrap is fastened to the lower arm 13 of the swan neck 11.
There is, on the other hand, shown in Fig. 9 a matrix-holding disk 180, that, at the periphery, is provided with two crowns of radial seats 280 for matrices 38, each corresponding to a punch 22 of the two punch-holding disks 150 of Fig.s 5 and 6.
As can be seen from Fig.s 1 and 3-9 the punch- holding disks 15, 150 and the matrix- holding disks 18, 180 are made to rotate by an electric motor 40 through a unit for the transmission of motion indicated as a whole with 41, comprising toothed pulleys 42, 43, 44, a toothed belt 45, transmission shafts 46 and 47 and toothed pinions 48 and 49 engaging with toothed wheels 50 and 51 made integral with the punch-holding disk 15 and with the matrix-holding disk 18, respectively.
In Fig.s 3-9 there are shown with 52 and 53 hydraulically-operated bolts, suitable for engaging with notches 54 and 55, also visible in Fig. 2, obtained on the front surfaces of the disk 15, or 150, and of the disk 18, or 180, respectively, at each punch 22 and at each matrix 38; the bolts 52 and 53 are used to clamp the same disks in any pre-selected operating position.
There is indicated with 56, and shown in Fig.s 1 and 2, an operating plane provided with brushes made of plastic material fibres, not shown, on which the sheet metal plane to be punched is caused to move; said brushes are preferably made as described in the Italian patent application No. 21819 A/90, in the name of the same Applicant.
The electric motor 40 is operationally connected, by means of a line 110, to an electronic control unit, indicated digrammatically by the block 57 of Fig. 1, by means of which an operator executes pre-selected operating cycles of the machine 10.
Solenoid valves, not shown, of the actuators of the bolts 52 and 53 are operationally connected to the same control unit 57.
There is indicated as a whole with 60 a manipulator, shown in Fig.s 1, 2 and 10, 11, constituted by a carriage 62 sliding in horizontal guides 63 integral with the upper arm 12 of the swan neck structure 11, and by a clamp-holding bar 64 sliding in guides 65 integral with the same carriage 62, in a direction horizontal with, and orthogonal to, the guides 63.
The carriage 62 receives motion from an electric motor 66 through a mechanism with a screw 67 and nut 68, integral with the same carriage; the clamp-holding bar 64 receives motion from an electric motor 69 through a speed reduction unit, not represented, and a mechanism with a pinion 70 and a rack 71, integral with the same clamp-holding bar; the electric motors 66 and 69 are operationally connected to the control unit 57 through lines 111 and 112.
The clamp-holding bar 64 slidingly supports clamps indicated as a whole with 73, clearly visible in Fig.s 10 and 11; each clamp 73 is formed by a lower jaw 75 and by an upper jaw 76.
The lower jaw 75 of each clamp is guided in its sliding motion by four rollers 74, mounted idle in the bar 64 and provided with races suitable to engage themselves with the V-shaped sides of the same lower jaw 75, as also shown in Fig. 12; each jaw 75 is provided with fins 176, which are up against two rollers 74 under the thrust exerted by a chain 77, visible in Fig. 10, through idle pinions 78, whose pivots are integral with each of the jaws 75; the chain 77 is also wound round the idle pinions 79, whose pivots are integral with the clamp-holding bar 64, and is kept tight by a pneumatic actuator 80, with a cylinder and piston, through an idle pinion 81, whose pivot is integral with the stem of the piston of the same actuator 80.
As can be seen from Fig. 11, the upper jaw 76 of each clamp 73, that is provided with a tooth 82 for grasping the sheet metal plate, is supported by the jaw 75 by means of a pivot 83 having a partially spherical head, against which it is kept by a spring 84, and is housed with a small clearance in a seat 85 obtained in the same jaw 75; the upper jaw 76 is connected to a movable casing 86 of a hydraulic actuator indicated as a whole with 87, by means of a pivot-shaped extremity 88, inserted in a groove 89 of the same casing 86.
In the same casing 86, that is connected to the jaw 75 by means of a runner 98 and a spring 99, there is obtained a cylinder 90 inside which a piston 91 sealingly slides, provided with a shank 92 screwed onto the jaw 75; the chamber 93 between cylinder 90 and piston 91 is connected, through a mechanically-operated three-way distributor 94, and a four-way electro-distributor 95, visible in Fig. 13, to a pump 96, capable of supplying oil under pressure, and to a discharge 97 of the same oil; the electro-distributor 95 is operationally connected, by means of conductors not shown, to the control unit 57 of Fig. 1.
There is indicated as a whole with 100 a control device comprising a lever 101 and a detector unit formed by a roller 102, capable of detecting a stop constituted by a ramp 103, obtained in the arm 12 of the swan neck structure 11; there is indicated with 104 a limit stop fastened to the lower arm 13 of the same structure 11.
There is indicated with 105 a cylinder, shown in Fig.s 1 and 2, that keeps the sheet metal plate slightly raised as it rests on the operational plane 56, during the rotation of the disks 15, 18, or 150, 180, to avoid any contact between the same sheet and the matrices 38 in motion.
The machine 10 described is initialized by the operator by introducing into the control unit 57 the information related to the programmed operating cycle.
On the basis of the programming data, the electric motor 40, through the transmission 41, rotates the punch- holding disks 15, or 150, and matrix- holding disks 18, or 180, in the same direction through a given angle to bring the pair of selected tools to the operating position, where they are clamped by the bolts 52 and 53; the sheet metal plate to be punched is placed on the operating plane 56, that, as has already been said, is preferably provided with brushes suitable for supporting the same sheet, while still allowing the free movement of the clamps 73; the same sheet is positioned by the operator so that it assumes the desired initial position with respect to the manipulator 60 and to the pair constituted by punch 22 and matrix 38, brought to the operating position; the clamps 73 are then operated through the electro-distributor 95 and the distributors 94, that, by sending oil under pressure to the chambers 93 of the actuators 87, cause the casing 86 to move upwards and the upper jaws 76 of the same clamps to grasp the the sheet metal plate between the tooth 82 and the lower jaw 75.
By means of the operating device 28 the punching operation of the sheet metal plate is executed, with the scrap discharged through the passage 39.
To displace the sheet metal plate in the operating plane 56, the clamps 73 are made to translate by the bar 64 and/or by the carriage 62 of the manipulator 60, whose movements are operated by the electric motor 69 and by the mechanism with a pinion 70 and rack 71, and by the electric motor 66 and by the mechanism with a screw 67 and nut 68, respectively.
There then take place a succession of displacements of the manipulator 60, a succession of rotations of the punch- holding disks 15, or 150, and matrix holders 18, or 180, and a succession of operations on the part of the operating device 28 up to the complete execution of all punching operations programmed on the basis of the drawing of the sheet metal workpiece to be produced.
The control device 100 of the manipulator 60 allows the automatic exclusion of the clamp 73 that would interfere with the punch 22 in the operating position.
If it happens that the carriage 62, moving towards the disks 15 and 18, goes beyond a safety limit, the roller 102 associated with the clamp 73 that is aligned with the punch 22, coming into contact with the ramp 103, through the lever 101, operates the distributor 94 to discharge the oil in the chamber 93 of the actuator 87, so that same clamp 73 opens, while the sheet metal plate continues its movement, under the action of the other clamps that have remained closed.
When the forward edge of the clamp 73 comes into contact with the limit stop 104, the same clamp 73, that had opened, can slide with respect to the bar 64, guided by the rollers 74; the consequent movement of the chain 77 and of the pinions 78, 79, 81, allows the clamp to be kept up against the stop 104 with a constant force, equal to about twice the force exerted normally by the actuator 80, in spite of the long stroke of the same clamp, that in some cases can be equal to the thickness of the disks 15, or 150, and 18, or 180.
When the punch-holding disk 150 and the matrix-holding disk 180, provided with two crowns of tools, are mounted in the machine 10, once two pairs of punches 22 and matrices 38 have been brought to the operating position, the operational pair is selected by means of the piston 34 and the tappet 33 of Fig. 5, or the tappet 330 of Fig.s 6 and 7.
Advantages of the proposed machine 10 are a small size and the ease of transportation and installation on site, as it is entirely assembled and tested in the production workshop.
The described machine 10 is also easy to programme due to the control device 100 capable of opening the clamp 73 and of bringing to a stop if it can interfere with a punch 22, while the other clamps can continue their motion, moving the sheet metal plate to be punched along with them.

Claims

Programmable machine capable of punching metal plates, particularly in large sheets, comprising a force structure substantially conformed in the shape of a swan neck (11), defining a horizontal operating plane (56) for a sheet of metal plate, and provided with at least one punch (22) operationally connected to an operating device (28), with at least one matrix (38) and with a manipulator (60) comprising in turn at least one carriage (62) that is slidably supported by said swan neck structure (11) and that supports in an orthogonally slidable way at least one bar (64) provided with clamps (73) operationally connected to actuator means (87) capable of operating them so as to grasp and release said sheet metal plate, said machine being characterized in that it comprises at least one first rotating disk (15; 150) provided at the periphery with at least one crown of radial seats (21), that house at least one crown of punches (22) operationally connected to said operating device (28), and at least one second rotating disk (18; 180) provided at the periphery with at least one crown of radial seats (280) that house at least one crown of matrices (38), said disks (15; 150, 18; 180) being rotatably supported in said swan neck structure (11) by means of horizontal pivots (14, 16) having the axes (19, 20) one above the other and lying substantially in the vertical centre-line plane (10) of the same swan neck structure (11), so that the same rotating disks (15; 150, 18; 180) are arranged complanar and one above the other, one upper (15; 150) and one lower (18; 180), on the front of said swan neck structure (11), said disks being capable of being operated so that they can execute pre-established angular displacements for positioning a pre-selected punch (22) and a corresponding matrix (38) in a pre-established operating position, aligned with one another, with respect to said operating plane (56).
Machine according to claim 1, characterised in that said first rotating disk (150) is provided at the periphery with two crowns of radial seats (21), that house two crowns of punches (22), and said second rotating disk (180) is provided at the periphery with two crowns of radial seats (280) for matrices (38), the punches (22) of said two crowns being operationally connectable to said operating device (28) by means of a tappet (33, 330) displaceable by a fluid-dynamic actuator (34) between a position of engagement with the punches (22) of one crown and another position of engagement with the punches (22) of the other crown.
Machine according to claim 1, characterised in that said manipulator (60) comprises a control device (100) for each clamp (73) operationally connected to said actuator means (87) and to means (102) for detecting a pre-selected stop (103), said control device (100) being capable of operating the same clamp (73) to release said sheet when said stop (103) is detected, each of said clamps (73) being supported by said bar (64) in a manner that is independently slidable in said sliding direction of the carriage (62), and being capable of engaging with a pre-selected limit stop (104), capable of preventing it from chasing said sheet metal plate, against the action of thrust means (77, 78, 79, 80, 81) capable of keeping it up against another limit stop (74) integral with said bar (64).
Machine according to claim 3, characterised in that each of said clamps (73) is formed by a lower jaw (75) and by an upper jaw (76), said lower jaw (75) being slidably supported in said bar (64) by idle rollers (74), and being provided with fins (176) which are up against two of said rollers (74) under the thrust exerted by said thrust means (77, 78, 79, 80, 81) constituted by a chain (77), by idle pinions (78), whose pivots are integral with each of said jaws (75), by idle pinions (79), whose pivots are integral with said clamp-holding bar (64), by a pneumatic actuator (80), with a cylinder and piston, and by an idle pinion (81), whose pivot is integral with the stem of the piston of the same actuator (80).
Machine according to claim 4, characterised in that said upper jaw (76) of each clamp (73) is supported by said lower jaw (75) by means of a pivot (83) having a partially spherical head, against which it is kept by a spring (84), said actuator means (87) comprising a movable casing (86) to which said upper jaw (76) is connected by means of a pivot-shaped extremity (88), inserted in a groove (89) of the same casing (86).
Machine according to claim 5, characterised in that said movable casing (86) is connected to said jaw (75) by means of a runner (98) and a spring (99), and is provided with a cylinder (90) inside which a piston (91) sealingly slides, provided with a shank (92) screwed onto said lower jaw (75), said cylinder (90) being connected, by means of distributors (94, 95), to a pump (96), capable of delivering oil under pressure, and to a discharge (97) of the same oil.