CA2105587A1 - Sheet bending machine - Google Patents
Sheet bending machineInfo
- Publication number
- CA2105587A1 CA2105587A1 CA002105587A CA2105587A CA2105587A1 CA 2105587 A1 CA2105587 A1 CA 2105587A1 CA 002105587 A CA002105587 A CA 002105587A CA 2105587 A CA2105587 A CA 2105587A CA 2105587 A1 CA2105587 A1 CA 2105587A1
- Authority
- CA
- Canada
- Prior art keywords
- bending
- punch
- sheet
- punches
- bending machine
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Abandoned
Links
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
- B21D—WORKING OR PROCESSING OF SHEET METAL OR METAL TUBES, RODS OR PROFILES WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
- B21D5/00—Bending sheet metal along straight lines, e.g. to form simple curves
- B21D5/02—Bending sheet metal along straight lines, e.g. to form simple curves on press brakes without making use of clamping means
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
- B21D—WORKING OR PROCESSING OF SHEET METAL OR METAL TUBES, RODS OR PROFILES WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
- B21D5/00—Bending sheet metal along straight lines, e.g. to form simple curves
- B21D5/04—Bending sheet metal along straight lines, e.g. to form simple curves on brakes making use of clamping means on one side of the work
- B21D5/042—With a rotational movement of the bending blade
Landscapes
- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- Bending Of Plates, Rods, And Pipes (AREA)
Abstract
Sheet bending machine Abstract:
There is disclosed a sheet bending machine (1) comprising two adjacently arranged and pivotally connected bending punches (19, 20), at least one of which is pivotally mounted and coupled to a pivot drive (24), and comprising a counter-punch (10) located opposite the bending punches (19, 20) and arranged to be linearly movable between a working position on the metal sheet (18) and a retracted position, about which the sheet (18) is bent in the working position, wherein the two bending punches (19, 20) in the working region are directly connected with each other by a hinge joint connection (53) along their edges facing each other in the at-rest position.
There is disclosed a sheet bending machine (1) comprising two adjacently arranged and pivotally connected bending punches (19, 20), at least one of which is pivotally mounted and coupled to a pivot drive (24), and comprising a counter-punch (10) located opposite the bending punches (19, 20) and arranged to be linearly movable between a working position on the metal sheet (18) and a retracted position, about which the sheet (18) is bent in the working position, wherein the two bending punches (19, 20) in the working region are directly connected with each other by a hinge joint connection (53) along their edges facing each other in the at-rest position.
Description
Sheet sending Machine Field of the Invention The invention relates to a sheet bending machine comprising three punches, i.e. two adjacently arranged and pivotally interconnected bending punches defining a sheet bearing plane with sheet contacting zones in the at-rest position, and a counter-punch located opposite the bending punches and linearly movable between a working position at the sheet and a retracted position, wherein two punches are pivotably mounted and are each coupled with a pivot drive, and wherein the sheet is bent about the counter-punch in the working position by pivoting at least one of the bending punches.
Background Art The best known and most widely adopted technique for bending metal sheets or folding consists in moving an upper bending punch a~ainst a sheet resting on a lower die, the bending punch pressing the sheet into the die in the region where the bent edge is to be formed (cf., e.g., FR-A-2 201 973 and also US-A-2 649 128), thus causing the sheet to be bent. In doing so, it is disadvantageous that, as a rule, no precisely defined or sharp bent edges can be formed, that for each die only a very specific bend, i.e., a very specific angle of bend, can be produced and that, furthermore, a considerable portion of the energy applied is lost due to friction on the die. These disadvantages basically also apply to those die machines in which the die is subdivided into two die p~rts movably mounted in a holder and, in particular, also pivotably connected to each other, cf. in this context, for example DE-C-115 961 or EP-A-379 886, FR-A-1 221 933 and DE-A-1 402 118, DE-A-2 418 668, US-A-1 045 089, US-A-l 258 892, US-A-1 633 744, US-A-2 433 841, JP-A-62-127125, JP-A-63-36923 as well as JP-A-63-199028. In all these structures, the actual bending work is applied by the upper bending punch, which must be accordingly sturdy and equipped with a correspondingly heavily dimensioned actuating drive.
Also known is a bending machine for already profiled sheets (W0 81/02535), in order to provide-these sheets with a corrugation, wherein an upper punch, which is movable up and down, cooperates with a stationary lower punch and with oblique auxiliary punches disposed on either side thereof and movable ,, . :.
, obliquely up and down in the direction of their principal plane.
While the upper punch, together with the opposite stationary lower punch, forms the corrugation in the sheet, the two lateral oblique punches preform the next corrugation. This known bending machine is not designed and also not suitable for a simple bending of a sheet with the sharpest bent edge possible.
Furthermore, manually operated pivotal bending machines are known, cf. US-A-3 877 279, in which the sheet to be bent is clamped between a stationary lower web and an upper web clampable thereagainst and in which the bending operation is performed by one lower pivotal bending punch. Then, in US-A-3 044 526, or DE-A-1 402 838, respectively, in US-A-3 282 976, in GB-A-l 119 811 and in GB-A-2 050 887 sheet bending machines were proposed, in which two lower bending punches can be pivoted about horizontal axes in opposite directions in order to bend the sheet to be bent about an upper counter-punch locatQd opposite them. The pivot bearings for the two lower bending punches are mounted externally on the two end faces of the bending machine, the pivot drives in the form of working cylinders also being provided on these end faces. It is disadvantageous that the bending punches must be of an extraordinarily heavy construction, in particular where large machine widths (e.g., 2 m or 3 m) are desired, wherein no precise bend can be achieved in the region of the machine centre, anyway, but the bent sheet in this central region, as a rule, will even be "more open" than in the region of the ends, i.e., the bent sheet will have a curved, convex shape, viewed along the length of the bend. The necessary massive construction of the bending punches in general also implies a limited machine width on account of the necessary masses, i.e., machine widths exceeding 3 m are hardly feasible, because the total mass of the machine would excessively increase accordingly. This would result in bending machines having masses of 15 to 20 tons.
Summary of the Invention I~ is an ob~ect of the invention to provide a bending machine of the initially defined type, which enables the bending of sheets while producing sharp bending edges at a relatively low energy consumption, wherein, in particular, also a variety of profiles are~to be realized by multiple bending, and which is based on as ., ,il `r - . ~ ~ .
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simple a structure as possible, requiring, in particular, substantially less massive constructions for the punches and the frame than hitherto necessary and, thus, resulting in a considerable reduction of mass. In addition, the most careful - treatment of the sheets possible during bending is sought.
The sheet bending machine of the initially stated type is, according to the invention, characterized in that the two bending punches, along their edges facing each other in the at-rest position, are directly connected with each other over the width of the bending machine by a hinge joint connection offset from the sheet bearing plane, a depression being provided in each bending punch between the sheet contacting zone of the bending punch and !, the hinge joint connection, and in that the bending punches are equipped with detachable tool segments adjacently arranged over the width of the bending machine, which tool segments are interconnected in pairs by hin~e jo~nt connections, the hinge joint connection of the bending punches being formed by the hinge joint connections of all the tool segment pairs.
i The bending machine according to the invention, thus, comprises an articulated connection of the two bending punches in the working region, a power flux being provided via this hinge-joint connection during bending of sheets, which results in the at least partial balancing of the horizontal components of the forces applied during bending in the hinge, this being achieved directly in the working region, which is essential, thus obviating massive pivot bearings at the end faces of the bending punches, on the one I hand, and massive constructions of the bending punches themselves, j on the other hand. Experiments proved that, compared to bending machines of, for instance, 15 tons, the same bending performances can be attained with a bending machine constructed according to `- the invention and having a total mass of not more than approximately 2 tons, which means that a reduction in mass to l/5 to 1/10 is feasible. By offsetting the hinge joint connection from the sheet bearing plane and by providing the depressions in the bending punches, both, a gentle treatment of the sheets during bending and an optimum force conversion at the beginning of the bending work are obtained. By e~uipping the bending punches with the individual tool segments that are articulately .
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21~:5~87 - -interconnected in pairs, a rapid conversion of the bending machine is made possible, wherein, in particular, also different working widths are feasible.
In view of the reduction in mass sought, it is also particularly advantageous if, distributed over the width of the bending machine, several pivot drives engage at each of the two independently pivotable bending punches, and the counter-punch is only linearly movable.
In multiple bending, it may occur that the sheet to be bent strikes against the counter-punch with an already bent, angular portion whilst producing a second or third bend (socalled case of "collision"). This may be eliminated, for instance, by enabling the counter-punch to evade by pivoting. Yet, doing this requires the pivotal mounting of the counter-punch, wherein both the pivot bearing and the punch itself are to be appropriately dimensioned in order to enable the counter force to be applied in sheet bending. What is, therefore, frequently to be sought and provided in a preferred, although not absolutely necessary manner, is the merely linear movability of the counter-punch, and in order to provide for a possibility of evasion for the sheet to be bent and to enable further bending after striking against the counter-punch in the collision case referred to above, it is favourable if the two bending punches are associated with independent pivot drives.
By means of the independent pivot drives, it is possible to simply stop one bending punch in case of collision such that on the side of this bending punch where the side of the sheet including the already bent sheet portion is located, the sheet is held stationarily, whereas the other bending punch continues to be pivoted to further bend the sheet. Also with this asymmetrical mode of operation, at least the ma~or portion of the occurring horizontal components of the bending forces are compensated for via the hinge connection in a manner that only relatively small force components are introduced into the bending punches and, from there, into the frame.
An embodiment,that is kinematically equivalent to the aforementioned embodiments, yet may be preferred in some cases with regard to the construction of the stationary part of the bending machine (for instance, on account of the stationary fixing ~' , ~;
~ ~--2~ Q~ 7 of one sheet portion during bending), furthermore, ischaracterized in that one of the bending pun~hes is stationarily mounted and the other bending punch as well as the counter-punch are pivotably mounted, the pivotable bending punch being drivable at twice the angular speed of the counter-punch.
In general, the present bending machine, due to its articulated connection, is suitable for particularly extreme bending operations, and it is particularly advantageous if the counter-punch is designed to be retractable from the bending punches so as to enable folding of the sheet in the final phase of bending of the sheet.
~ ecause of the hinge connection of the bending punches according to the invention, it is possible with the present bending machine in an advantageous manner to hold the tool segments on the bending punches, which then serve as toolholders, on the side located opposite the sheet contacting zones by means of a simple plug-in connection, e.g., a tonge-and-groove connection.
In order to facilitate the assembly and the replacement of the tool segments, it is, furthermore, particularly advantageous if the tool-segement pairs are provided with separate hinge pins adapted to the length of the segments. To hold the adjacent tool segments at each other, it is furthermore advantageous if the tool segment hinge pins each pro;ect into the hinge eyes of the adjacent tool segment pair on one side. When exchanging tools, all of the hinge pins that are aligned may then, for instance, be commonly displaced linearly by the measure by which they each project relative to the neighbouring segment, until the segments are no longer held together.
On the other hand, it may be preferable for reasons of stability to provide a common continuous hinge pin extending through all of the segment tools.
To facilitate replacement in view of the wear occurring during operation, it is also favourable for the tool segments to be provided with separate inserts forming the sheet contacting zones. ~hese inserts may be screwed to the tool segments.
A particularly advantageous and effective driving facility has proved to be obtained by a circular arc-shaped toothed rail ' :
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being provided as the pivot drive, firmly connected with the associated bending punch and driven by a pinion mounted on a shaft. It is, furthermore, advantageous if the toothed rail is mounted in a circular arc-shaped bearing, e.g., in a bearing groove, on a stationary bearing part. In this manner, the respective bending punch can be mounted on the frame of the bending machine simultaneously via the toothed rails.
It is also advantageous to provide two separate electric motors for rotatably driving the two shafts associated with the bending punches.
Brief Description of the Drawings , The invention will be explained in further detail below by way of particularly preferred exemplary embodiments illustrated in the drawings, to which it is, however, not limited. Therein:
Fig. 1 is a diagrammatic overall view of a sheet bending machine according to the invention in the at-rest position;
j Fig. 2 is a sectional diagrammatic view of a part of this bending machine in the region of the bending tools in an operating position on an enlarged scale as compared to Fig. 1;
Fig. 3 is a schematic end view of the main components of the bending machine according to Figs. 1 and 2;
Fig. 4 is an exploded view of a tool-segment pair including a hinge ~oint for the bending punches of the bending machine according to Figs. 1 to 3;
Figures 5, 6 and 7 represent the bending tools and a sheet to be bent in schematic end views in various bending phases;
Fig. 8 is an end view of one of the bending punches of the I bending machine according to Figs. 1 to 7, yet in an embodiment modified in respect of Figs. 1 to 7;
Fig. g is an embodiment modified in respect of Fig. 8 in a corresponding end view;
Fig. 10 is a schematic diagrammatic view of the arrangement of the bending tools in a further modified bending machine; and Figures 11, 12 and 13, in a manner similar to Figures 5, 6 and 7, illustrate different phases in sheet bending by means of the bending machine according to Fig. lO, Fig. 11 representing the starting position, Fig. 12 representing an intermediate position and Fi~. 13 representing the end position.
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Detailed Description of Preferred Embodiments According to Fig. 1, the instant sheet bending device, bendin~ machine or bending press as particularly preferred at present and generally denoted by 1 comprises a lower frame 2, on which vertical guides 5 are provided in main end supports 3, 4, in which an upper toolholder 9 including a web- or sword-shaped counter punch 10 (also termed upper tool or simply sword) is guided so as to be vertically displaceable up and down.
Preferably, this counter-punch 10 is exchangeably attached to the toolholder 9, yet also could be designed integral therewith;
preferably, a more or less cutting edge-likely designed lower bending edge 13 ~cf. Fig. 3) is provided, yet other cross-sectional shapes may be provided as well - depending on the bend to be produced.
For lifting and lowering the upper counter-punch 10, conventional spindle drives are, for instance, provided, as is schematically illustrated in Fig. 1 at 14. These spindle drives 14, for instance, include a spindle 16 driven by an electric driving motor, if desired, via a gear and a clutch (not shown) and cooperating with a spindle nut 17 connected to the toolholder 9 in order to move the toolholder 9 with the counter-punch 10 up and down in the guides 5 during the rotation of the spindle. These spindle drives 14 and other drive means still to be explained are attached to the frame 2 in a conventional manner.
Furthermore, two lower, plate- or web-shaped bending punches 19, 20 are provided for bending a sheet 18 (cf. Figs. 5 to 7).
These two lower bending punches 19, 20 are pivotably mounted on the frame 2 in a manner to be explained later on, being pivotable about a common pivot axis 21 (cf. Figs. 5 to 7) located in the region of the bending edge 22 to be produced in the sheet 18 to be bent, yet slightly therebelow, in particular also within the plane 23 (Figs. 3 and 5) of the upward and downward movements of the counter punch 10 defined by the guides 5 and 6.
The drive for pivoting the lower bending punches 19, 20 about the common pivot axis 21 is formed by a pivoting mechanism, which in the instant exemplary embodiment, comprises several pivot drives in the form of rack-and-pinion gears schematically indlcated at 24 in Figs. 1 to 3, distributed over the width of the ` - 8 - 21~5~7 bending machine 1. In detail, a respective circular arc-shaped toothed rack or rail 61, 62 is fixed to the lower region of the respective lower bending punch 19 or 20, respectively, as is also apparent from Figs. 8 and 9 in addition to Figs. 1 to 3. These ~-toothed racks or segments 61, 62, mesh with e.g. equally large toothed wheels 63 and 64 respectively seated on shafts 27 and 28 that are parallel to each other and to the bending punches 19, 20.
The two shafts 27, 28 each are driven by a - for instance, electric - drive motor 72, 73, optionally via a gear not illustrated, as is apparent from Fig. 1. The two shafts 27, 28 extend over the total width of the bending machine 1 and are rotatably journalled on the frame 2 in appropriate baaring parts 75 to be explained in more detail hereinafter, on the end faces as well as on intermediate points in the region of the individual rack-and-pinion gears 24. For each toothed rack gear 24, there is provided a toothed rack 61 and 62 as well as a toothed wheel 63 and 64 mounted on the respective shaft 27 and 28, respectively, for rotation therewith, and, as already pointed out above, several such rack-and-pinion gears 24 are distributedly provided over the width of the bending machine 1 as pivot drives in order to be able to apply the driving torque in a distributed manner. Therefore, with the shafts 27, 28 being rotationally driven, the toothed racks 61, 62 are moved according to a circular arc-shaped path whose centre is located on the pivot axis 21, pivoting apart the lower bending punches 19, 20 connected to them in the way of straddling apart, cf., in particular, Fig. 5 (inoperative position) as well as Figs. 6 and 7 (pivoted apart working position).
Several bearing parts 75 extending transversely to a stationary cross beam 74 of the frame 2 are fixed to the cross beam 74 on the sites of the rack-and-pinion gears 24 in a manner distributed over the machine width for mounting the shafts 27, 28, on the one hand, and the bending punches 19, 20, on the other hand, on the frame 2 as indicated above. These bearing parts 75, on the one hand, i~clude bearings 77 that are exchangeable through removable bearings lids 76 (cf. Figs. 2 and 3~ for the shafts 27, 28, and, on the other hand, are provided with circular arc-shaped slide grooves 78 on both sides in their upper regions (rf. Fig. 2, .. . : .
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~ 9 2105~7 right side), in which the circular arc-shaped toothed racks or toothed segments 61, 62 are slidably guided by means of correspondingly curved guiding keys or ledges 79 provided on them.
Thus, two toothed segments 61, 62 are each slidably guided on such a bearing part 75, one for the shaft 27 and the other for the shaft 28. By means of this bearing arrangement comprising the comparatively firmly constructed toothed racks 61, 62, their guiding keys 79, the circular arc-shaped slide grooves 78 and the bearing parts 75, the load is absorbed in a manner distributed over the machine width such that the forces occurring in bending and to be absorbed are introduced into the frame 2 and its cross beam 74 also in a distributed manner. Thus,the relatively not very massive construction of the bearing parts 75 will do.
It should be mentioned that in the illustration of Fig. 3, only the pinion 63 associated with the shaft 27 can be seen, which, as illustrated, is located in front of the bearing part 75 also in Figs. 1 and 2, and the pinion 64 associated with the shaft 28 and located behind this bearing part 75 accordingly is indicated by a broken line in Fig. 3. On the other hand, the bearing 77 for the shaft 28, which is accessible via the bearing lid 78, can be seen from this representation in Fig. 3 at the shaft 28 indicated on the right-hand side, cf. also Fig. 2.
Furthermore, it is apparent from Fig. 3 that the two shafts 27, 28 are designed with cross-sections having the form of what is called a "lobed cylinder" in order to be able to receive the pinions 63, 64 in a rotationally fixed manner without weakening the cross , section, such as, for instance, in the case of a key-key way connection. The respective bending punch 19, 20, with the pertaining toothed segment 61, 62, respectively, may, for instance, be received in a simple plug-in seat or press-in seat between seat pro~ections 80, 81 formed integral with the respective toothed segment 6~, 62, cf. Figs. 8 and 9 in addition to Fig. 3, but it may also be screwed therewith.
From Figs~ 2 and 3 it is apparent that the two bending punches 19, 20 are,articulatedly connected along their upper inner edges by a hinge ~oint connection over the entire working width.
According to Fig. 4, intermeshing hinge eyes 52 are provided, through which a hinge pin 54 extends in the assembled state. This -..... . , ~ . . . , : ~ ................ ., ,,. ~ . . :.
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2105~`~7 hinge joint connection 53, with the hinge pin 54, defines the aforementioned pivot axis 21 about which the two bending punches 19, 20 are pivoted in operation.
In detail, the bending punches 19, 20 are designed as tool-holders including separately removable and exchangeable tool segments 55, which tool segments 55 are articulatedly connected in pairs by the hinge pins 54 each adapted accordingly in terms of length. These tool segments 55 are retained in the bending punches 19, 20 functioning as toolholders by a simple plug-in connection comprising a longitudinal tongue 82 and a pertaining groove 83 such that the tool segments 55 can be exchanged in a particularly simple and quick manner. It has been found that, surprisingly, no fixed connection is required between the individual tool segments 55 and the respective toolholder or bending punch 19, 20, which also goes back to the fact that, duxing operation, of the forces occurring during bending, the horizontal components are compensated for, at least substantially, by the hinge joint 53 such that only vertical forces or forces acting in the plane of the bending punches 19, 20 are transmitted by the plug-in connection (tongue 82, groove 83), which is readily feasible by means of this tongue-and-groove connection 82, 83. In view of the wear occurring during operation, it may, however, be suitable to provide tool inserts 85 which apply the bending work proper to the sheet via contact zones 84 (cf. Fig. 8 in addition to Figs. 3 and 4), which inserts 85, for instance, are comprised of hard metal inserts to be screwed to the tool segments 55 - or to the bending punches 19, 20, respectively - by bolts 86, cf. Fig. 8. A modified insert design additionally including a tongue-and-groove-connection 87 for the hard metal insert 85 is represented in Fig.
9. In Figs. 8 and 9, furthermore the tool segments 55 (according to Figs. 1 to 7) are indicated in bro~en lines ; in this case, the inserts 85 may be segmented in accordance with the tool segments 55.
In the following, the mode of functioning of the sheet bending machlne 1 will be explained by way of the schema~tic illustration o~ Figs. 5 to 7 as well as with reference to Figs. 2 and 3 (in which the left bending punch 19 is shown in the pivoted state).
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2~ 7 The starting or at-rest position of the sheet bending machine 1 is illustrated in full lines in Fig. 5. The upper counter-punch 10 has assumed its resting position lifted off the sheet 18, and in this position a metal sheet 18 to be bent can be fed manually , or automatically to the bending machine 1 and positioned there.
`~ When a sheet bending cycle is started, the counter-punch 10 at first is moved downwards by means of the spindle drives 14 (Fig.
', 1) until it contacts the sheet 18 to be bent and positioned on the lower bending punches 19, 20, by its edge 13. This phase, in which the sheet 18 is virtually clamped between the three punches or tools 10, 19 and 20, also is illustrated in Fig. 5 with the counter-punch 10 shown in broken lines.
After this, the drive to the driving shafts 27, 28 of the rack-and-pinion drive 24 for the lower bending punches 19, 20 is switched on. Accordingly, the toothed racks 61, 62 are driven along the slide grooves 78 (Fig. 3), pivoting the bending punches 19, 20 about their common pivot axis 21 in opposite senses, i.e., according to the illustrations in Figs. 5 and 6, the left bending punch 19 is pivoted in clockwise direction and the right bending ~ punch 20 is pivoted in counter-clockwise direction. By aid of the `1 pivoting lower tools 19, 20, the sheet 18 at first, e.g., is symmetrically bent, bearing against the lower edge 13 of the upper counter-punch 10, a bending edge 22 thus being produced, cf. Fig.
6. Suitably, the counter-punch 10 is fixed or blocked in its position during this bending procedure, for instance, by means of the spindle drives 14 (Fig. 1) themselves, such that it ~ constitutes a stationary counter-holder during this bending 1 operation. The sheet 18 is bent along the bending edge 22, e.g., by about 90, cf. Fig. 6; as is, furthermore, illustrated in Fig.
7, also an acute bend angle may be realized in the sheet 18. If the sheet 18 has already been subjected to a bending operation, see the bent edge 34 in Figs. 5 to 7, the so-called "collision case~ may occur, in which the bent edge 34 strikes against the counter-punch 10 during bending. In order to prevent undesired deformations in the. sheet 18 when further driving the bending ~j punches 19, 20, the upper counter-punch 10 could, for instance, be l mounted pivotably about a horizontal axis so as to be able to i~ evade when struck by the edge 34. In order to obviate for the ..
2 1 ~ 7 ~ 12 -counter-punch 10, the pivot bearings required in this case, a different solution may be provided for this collision case, it being advantageous that a force balance is provided by the hinge joint; therefore, asymmetric modes of operation are premissible in addition to the described mode of operation in which the lower bending punches 19, 20 are driven symmetrically in opposite directions, in particular at equal angular speeds, since, on the whole, there remains only a relatively small resultant horizontal component. In this regard, independent pivot drives are preferably associated with the two bending punches 19, 20 in the present l sheet bending machine 1, by the separate drive motors 72, 73 and the shafts 27, 28 driven by them in the instant exemplary j embodiment. Conseguently, if the sheet edge 34 strikes against one ~, side of the counter-punch 10 in the collision case described, cf.Fig. 7, the bending punch 20 being on that side is stopped and only the other bending punch 19 is pivoted further in order to continue the bending operation on the sheet 18, as illustrated in l Fig. 7.
i However, it would also be conceivable instead, to pivot the ~ two bending punches 19, 20 from the start (Fig. 5) at different ,' speeds in order to reach the final position, for instance according to Fig. 7, in a continuous operation.
It would also be possible, after the situation shown in Fig.
] 7 has been reached, for the counter-punch 10 to be moved upwards i~ out of the sheet profile 18, whereupon the two bending punches 19, 20 are pivoted further upwardly in the manner of straddling, thus 7 producing a fold in the region of the bending edge 22 realized, i.e., the sheet edge on the left side in Fig. 7 would then be applied directly against the remaining sheet 18. For this bending ? phase, the friction forces applied on the sheet by these contact zones 84 turned out to suffice for holding the largely bent sheet 18 between the bending punches 19, 20 without the counter-punch 10 being required therefor.
, With the present bending machine 1, it is also important forZ the commencing bending operstion, cf. Figs. 5 and 6, that the i sheet contacting zones 84 described, which in the at-rest position of the bending punches 19, 20 (Fig. 5) define the bearing or seating plane 91 for the sheet 18, pass over into the hinge ~oint ` - 13 ~
53 via a depression 90. As bending commences, these depressions 90 provide room to the sheet 18 in the region of the bending ed~e 22 to be produced such that the sheet 18 will not be sque~zed there, as could be the case with adjacent bending punches flat on their upper surfaces. Moreover, it is apparent from Fig. 5 that the hinge pin or pivot axis 21 extends slightly below the sheet contact plane 91 defined by the contact zones 84 (i.e., the lower side of the sheet 18 in Fig. 5), whereby a favourable lever arm is created for transmitting the bending moment onto the sheet 18 in the commencing bending operation.
After completion of the bending operation, the several drives for the punches 10, 19, 20 are reversed in order to pivot the lower bending punches 19, 20 back into the vertical starting position according to Fig. 5 and to move the upper counter-punch 10 upwardly (unless done so far). The bent sheet 18 then may be brought into the subsequent bending position or may be removed from the bending machine 1.
In Figs. 10 to 13, a further sheet bending device 1 is schematically illustrated with its essential working components, completely corresponding to the previously described exemplary embodiment with regard to the relative movement of its punches or tools 10, 19, 20, wherein, however, during the bending process it is not the upper counter-punch 10 that is held stationarily, but one lower bending punch, according to Figs. 10 to 13 the right lower bending punch 20, whereas the other lower bending punch 19 during bending of the sheet 18 (cf. Figs. 11 to 13) is pivoted in correspondence with the previous exemplary embodiments and, moreover, the upper, counter-punch 10 - to induce the relative pivotal movements between the punches - preferably is pivoted at half the angular speed as compared to the left lower bending punch 19, see also the intermediate position of the three punches shown in Fig. 12 as well as the final position shown in Fig. 13. If, with this embodiment according to Figs. 10 to 13, the movement cycle were observed from the upper, counter-punch 10 (at-rest position), a pivotal-movement cycle similar to that previously explained by way of Figs. 1 to 9 would result. In Figs. 10 to 13, however, the individual phases of movement are shown as observed from the stationary frame (which is not illustrated in detail in .- ~ . . . ~ . ';
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210~587 Figs. 10 to 13). A kinematic system of the type as at the bending machine of Figs. 10 to 13 may be desired if only a slight movement, if any, is to be performed on the sheet 18 to be bent on the one side of the bending edge.
More in detail, in the exemplary embodiment illustrated in Figs. 10 to 13, the two lower bending punches 19, 20 again are articulatedly connected by interengaging eye members 52 to form the hinge joint 53, a hinge pin 54 extending through the entire hinge assembly. Laterally of the hinge ~oint 53, the two bending punches 19, 20 have a rounded cheek form where they contact the sheet 18 to be bent. With a view to an easy exchange, the two bending punohes 19, 20 are also assembled of individual tool segments 55, which are firmly connected with a toolholder or punch lower part 56, for instance, by means of bolts 57. As the pivot drive for the left lower punch 19, circular arc-shaped guide rails 58 provided with teeth on the lower side, which are not illustrated in detail, may be provided, extending through guiding slits 59 in the base part 56 of the other bending punch 20 and meshing with driving toothed wheels 60, which basically correspond to the toothed wheels 63 and 64 according to Figs. 1 to 9. The drive for these toothed wheels 60 may be effected via a drive motor not illustrated in detail and a gear in the manner already described in connection with Figs. 1 to 9.
Fig. 10 also schematically indicates in broken lines how the left punch 19 is pivoted outwardly, i.e., away from the right punch 20, as the toothed wheel 60 is rotated in the counter-clockwise direction (see arrow). For reasons of simplicity, it is not shown that, simultaneously with this pivotal movement of the one lower punch 19, also the upper punch 10 is pivoted -preferably at half the angular speed of the lower punch 19 as mentioned before.
The drive of the upper punch-10 basically may be effected in a manner analogous to that of the lower punch 19, the preferred transmission ratio of 2 : 1 being ensured by means of a gear. Such a drive assembly is conventional per se and need not be discussed here in detail.
Furthermore, it should be noted that the mounting of the upper punch 10 in the frame not illustrated in detail, with the .
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2~5~7 ~s - 15 -bending machine according to Fig. 10, basically may be realized in a manner similar to that previously discussed by way of Fig. 1, i.e., in particular, with end-side main supports 3, 4, which, however, would have to be mounted pivotably on the lower frame 2, e.g., together with the spindle drives (14 in Fig. 1) or similar drives, which may be effected in a manner known to a person , skilled in the art.
In Figs. 11 to 13, the pivot axis 21 for the relative pivotal movement between the lower bending punches 19, 20 is illustrated, which, in this case, coincides with the geometrical axis of the hinge pin 54 of the hinge joint 53 (Fig. 10). During bending, also the upper punch 10 is pivoted about this pivot axis 21, cf.
illustration in Figs. 12 and 13.
~ he centre of the circular arc-shaped rails 58 is, of course, located on this pivot axis 21 (i.e., on the geometric axis of the hinge joint axis 54).
Although the invention has been explained in detailed manner by way of particularly preferred exemplary embodiments, other variants and modifications are feasible within the scope of the invention. Thus, it is, for instance, possible to provide the hinge joint connection 53 described in respect of Figs. 1 to 9 with a throughgoing hinge pin 54 having a length corresponding to the machine width. On the other hand, it is also possible with the distributedly arranged hinge joints, cf. Fig. 4, to allow the respective hinge pins 54 to pro~ect slightly beyond the tool segment pairs 55 on one side and to reach into the hinge eyes 52 of the consecutive pair of tool segments 55 in a manner that a connection between the individual tool segment pairs will be obtained.
Furthermore, instead of the described vertical orientation of the bending machine 1 with the sheet 18 to be bent having to be disposed horizontally, any other orientation, such as a substantially inclined one, may be chosen with the sheet 18 being positioned accordingly inclined in the starting position. For this purpose, only the frame parts would have to be modified accordingly.
Appropriate elec~ric control circuits can be provided for the drive motors, for instance, for the drive motors 72, 73 for , . ~ .
! . ' ; ,;; i 21U~7 pivoting the bending punches 19, 20 as well as for the drive motors for the two spindle drives 14, in order to be able to switch these drive ~otors on and off as required. In principle, these electrical drive motors may, of course, be replaced with hydraulic motors or pressure fluid cylinders.
In addition, it is possible to move the upper punch 10 up and down for instance by means of an eccentric drive or a working cylinder, wherein locking of the upper punch 10 in the lower working position, e.g., according to Figs. 2, 3, 6 and 7, if desired, may be obtained by simply stopping the eccentric drive in this position.
In a practical exemplary embodiment according to Fig. 1, the machine width was 1,500 mm, the length of the tool segments 55 was 125 mm, and the diameter of the hinge pin 54 was 8 mm; the pitch for the pivot drives 24 was 400 mm, the external drive units each having been offset relative to the end sides of the machine 1 by about 150 mm. The total mass of the bending machine 1 a~ounted to less than 500 kg, and 2 mm thick sheets could be bent without difficulty.
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Background Art The best known and most widely adopted technique for bending metal sheets or folding consists in moving an upper bending punch a~ainst a sheet resting on a lower die, the bending punch pressing the sheet into the die in the region where the bent edge is to be formed (cf., e.g., FR-A-2 201 973 and also US-A-2 649 128), thus causing the sheet to be bent. In doing so, it is disadvantageous that, as a rule, no precisely defined or sharp bent edges can be formed, that for each die only a very specific bend, i.e., a very specific angle of bend, can be produced and that, furthermore, a considerable portion of the energy applied is lost due to friction on the die. These disadvantages basically also apply to those die machines in which the die is subdivided into two die p~rts movably mounted in a holder and, in particular, also pivotably connected to each other, cf. in this context, for example DE-C-115 961 or EP-A-379 886, FR-A-1 221 933 and DE-A-1 402 118, DE-A-2 418 668, US-A-1 045 089, US-A-l 258 892, US-A-1 633 744, US-A-2 433 841, JP-A-62-127125, JP-A-63-36923 as well as JP-A-63-199028. In all these structures, the actual bending work is applied by the upper bending punch, which must be accordingly sturdy and equipped with a correspondingly heavily dimensioned actuating drive.
Also known is a bending machine for already profiled sheets (W0 81/02535), in order to provide-these sheets with a corrugation, wherein an upper punch, which is movable up and down, cooperates with a stationary lower punch and with oblique auxiliary punches disposed on either side thereof and movable ,, . :.
, obliquely up and down in the direction of their principal plane.
While the upper punch, together with the opposite stationary lower punch, forms the corrugation in the sheet, the two lateral oblique punches preform the next corrugation. This known bending machine is not designed and also not suitable for a simple bending of a sheet with the sharpest bent edge possible.
Furthermore, manually operated pivotal bending machines are known, cf. US-A-3 877 279, in which the sheet to be bent is clamped between a stationary lower web and an upper web clampable thereagainst and in which the bending operation is performed by one lower pivotal bending punch. Then, in US-A-3 044 526, or DE-A-1 402 838, respectively, in US-A-3 282 976, in GB-A-l 119 811 and in GB-A-2 050 887 sheet bending machines were proposed, in which two lower bending punches can be pivoted about horizontal axes in opposite directions in order to bend the sheet to be bent about an upper counter-punch locatQd opposite them. The pivot bearings for the two lower bending punches are mounted externally on the two end faces of the bending machine, the pivot drives in the form of working cylinders also being provided on these end faces. It is disadvantageous that the bending punches must be of an extraordinarily heavy construction, in particular where large machine widths (e.g., 2 m or 3 m) are desired, wherein no precise bend can be achieved in the region of the machine centre, anyway, but the bent sheet in this central region, as a rule, will even be "more open" than in the region of the ends, i.e., the bent sheet will have a curved, convex shape, viewed along the length of the bend. The necessary massive construction of the bending punches in general also implies a limited machine width on account of the necessary masses, i.e., machine widths exceeding 3 m are hardly feasible, because the total mass of the machine would excessively increase accordingly. This would result in bending machines having masses of 15 to 20 tons.
Summary of the Invention I~ is an ob~ect of the invention to provide a bending machine of the initially defined type, which enables the bending of sheets while producing sharp bending edges at a relatively low energy consumption, wherein, in particular, also a variety of profiles are~to be realized by multiple bending, and which is based on as ., ,il `r - . ~ ~ .
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simple a structure as possible, requiring, in particular, substantially less massive constructions for the punches and the frame than hitherto necessary and, thus, resulting in a considerable reduction of mass. In addition, the most careful - treatment of the sheets possible during bending is sought.
The sheet bending machine of the initially stated type is, according to the invention, characterized in that the two bending punches, along their edges facing each other in the at-rest position, are directly connected with each other over the width of the bending machine by a hinge joint connection offset from the sheet bearing plane, a depression being provided in each bending punch between the sheet contacting zone of the bending punch and !, the hinge joint connection, and in that the bending punches are equipped with detachable tool segments adjacently arranged over the width of the bending machine, which tool segments are interconnected in pairs by hin~e jo~nt connections, the hinge joint connection of the bending punches being formed by the hinge joint connections of all the tool segment pairs.
i The bending machine according to the invention, thus, comprises an articulated connection of the two bending punches in the working region, a power flux being provided via this hinge-joint connection during bending of sheets, which results in the at least partial balancing of the horizontal components of the forces applied during bending in the hinge, this being achieved directly in the working region, which is essential, thus obviating massive pivot bearings at the end faces of the bending punches, on the one I hand, and massive constructions of the bending punches themselves, j on the other hand. Experiments proved that, compared to bending machines of, for instance, 15 tons, the same bending performances can be attained with a bending machine constructed according to `- the invention and having a total mass of not more than approximately 2 tons, which means that a reduction in mass to l/5 to 1/10 is feasible. By offsetting the hinge joint connection from the sheet bearing plane and by providing the depressions in the bending punches, both, a gentle treatment of the sheets during bending and an optimum force conversion at the beginning of the bending work are obtained. By e~uipping the bending punches with the individual tool segments that are articulately .
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21~:5~87 - -interconnected in pairs, a rapid conversion of the bending machine is made possible, wherein, in particular, also different working widths are feasible.
In view of the reduction in mass sought, it is also particularly advantageous if, distributed over the width of the bending machine, several pivot drives engage at each of the two independently pivotable bending punches, and the counter-punch is only linearly movable.
In multiple bending, it may occur that the sheet to be bent strikes against the counter-punch with an already bent, angular portion whilst producing a second or third bend (socalled case of "collision"). This may be eliminated, for instance, by enabling the counter-punch to evade by pivoting. Yet, doing this requires the pivotal mounting of the counter-punch, wherein both the pivot bearing and the punch itself are to be appropriately dimensioned in order to enable the counter force to be applied in sheet bending. What is, therefore, frequently to be sought and provided in a preferred, although not absolutely necessary manner, is the merely linear movability of the counter-punch, and in order to provide for a possibility of evasion for the sheet to be bent and to enable further bending after striking against the counter-punch in the collision case referred to above, it is favourable if the two bending punches are associated with independent pivot drives.
By means of the independent pivot drives, it is possible to simply stop one bending punch in case of collision such that on the side of this bending punch where the side of the sheet including the already bent sheet portion is located, the sheet is held stationarily, whereas the other bending punch continues to be pivoted to further bend the sheet. Also with this asymmetrical mode of operation, at least the ma~or portion of the occurring horizontal components of the bending forces are compensated for via the hinge connection in a manner that only relatively small force components are introduced into the bending punches and, from there, into the frame.
An embodiment,that is kinematically equivalent to the aforementioned embodiments, yet may be preferred in some cases with regard to the construction of the stationary part of the bending machine (for instance, on account of the stationary fixing ~' , ~;
~ ~--2~ Q~ 7 of one sheet portion during bending), furthermore, ischaracterized in that one of the bending pun~hes is stationarily mounted and the other bending punch as well as the counter-punch are pivotably mounted, the pivotable bending punch being drivable at twice the angular speed of the counter-punch.
In general, the present bending machine, due to its articulated connection, is suitable for particularly extreme bending operations, and it is particularly advantageous if the counter-punch is designed to be retractable from the bending punches so as to enable folding of the sheet in the final phase of bending of the sheet.
~ ecause of the hinge connection of the bending punches according to the invention, it is possible with the present bending machine in an advantageous manner to hold the tool segments on the bending punches, which then serve as toolholders, on the side located opposite the sheet contacting zones by means of a simple plug-in connection, e.g., a tonge-and-groove connection.
In order to facilitate the assembly and the replacement of the tool segments, it is, furthermore, particularly advantageous if the tool-segement pairs are provided with separate hinge pins adapted to the length of the segments. To hold the adjacent tool segments at each other, it is furthermore advantageous if the tool segment hinge pins each pro;ect into the hinge eyes of the adjacent tool segment pair on one side. When exchanging tools, all of the hinge pins that are aligned may then, for instance, be commonly displaced linearly by the measure by which they each project relative to the neighbouring segment, until the segments are no longer held together.
On the other hand, it may be preferable for reasons of stability to provide a common continuous hinge pin extending through all of the segment tools.
To facilitate replacement in view of the wear occurring during operation, it is also favourable for the tool segments to be provided with separate inserts forming the sheet contacting zones. ~hese inserts may be screwed to the tool segments.
A particularly advantageous and effective driving facility has proved to be obtained by a circular arc-shaped toothed rail ' :
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being provided as the pivot drive, firmly connected with the associated bending punch and driven by a pinion mounted on a shaft. It is, furthermore, advantageous if the toothed rail is mounted in a circular arc-shaped bearing, e.g., in a bearing groove, on a stationary bearing part. In this manner, the respective bending punch can be mounted on the frame of the bending machine simultaneously via the toothed rails.
It is also advantageous to provide two separate electric motors for rotatably driving the two shafts associated with the bending punches.
Brief Description of the Drawings , The invention will be explained in further detail below by way of particularly preferred exemplary embodiments illustrated in the drawings, to which it is, however, not limited. Therein:
Fig. 1 is a diagrammatic overall view of a sheet bending machine according to the invention in the at-rest position;
j Fig. 2 is a sectional diagrammatic view of a part of this bending machine in the region of the bending tools in an operating position on an enlarged scale as compared to Fig. 1;
Fig. 3 is a schematic end view of the main components of the bending machine according to Figs. 1 and 2;
Fig. 4 is an exploded view of a tool-segment pair including a hinge ~oint for the bending punches of the bending machine according to Figs. 1 to 3;
Figures 5, 6 and 7 represent the bending tools and a sheet to be bent in schematic end views in various bending phases;
Fig. 8 is an end view of one of the bending punches of the I bending machine according to Figs. 1 to 7, yet in an embodiment modified in respect of Figs. 1 to 7;
Fig. g is an embodiment modified in respect of Fig. 8 in a corresponding end view;
Fig. 10 is a schematic diagrammatic view of the arrangement of the bending tools in a further modified bending machine; and Figures 11, 12 and 13, in a manner similar to Figures 5, 6 and 7, illustrate different phases in sheet bending by means of the bending machine according to Fig. lO, Fig. 11 representing the starting position, Fig. 12 representing an intermediate position and Fi~. 13 representing the end position.
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Detailed Description of Preferred Embodiments According to Fig. 1, the instant sheet bending device, bendin~ machine or bending press as particularly preferred at present and generally denoted by 1 comprises a lower frame 2, on which vertical guides 5 are provided in main end supports 3, 4, in which an upper toolholder 9 including a web- or sword-shaped counter punch 10 (also termed upper tool or simply sword) is guided so as to be vertically displaceable up and down.
Preferably, this counter-punch 10 is exchangeably attached to the toolholder 9, yet also could be designed integral therewith;
preferably, a more or less cutting edge-likely designed lower bending edge 13 ~cf. Fig. 3) is provided, yet other cross-sectional shapes may be provided as well - depending on the bend to be produced.
For lifting and lowering the upper counter-punch 10, conventional spindle drives are, for instance, provided, as is schematically illustrated in Fig. 1 at 14. These spindle drives 14, for instance, include a spindle 16 driven by an electric driving motor, if desired, via a gear and a clutch (not shown) and cooperating with a spindle nut 17 connected to the toolholder 9 in order to move the toolholder 9 with the counter-punch 10 up and down in the guides 5 during the rotation of the spindle. These spindle drives 14 and other drive means still to be explained are attached to the frame 2 in a conventional manner.
Furthermore, two lower, plate- or web-shaped bending punches 19, 20 are provided for bending a sheet 18 (cf. Figs. 5 to 7).
These two lower bending punches 19, 20 are pivotably mounted on the frame 2 in a manner to be explained later on, being pivotable about a common pivot axis 21 (cf. Figs. 5 to 7) located in the region of the bending edge 22 to be produced in the sheet 18 to be bent, yet slightly therebelow, in particular also within the plane 23 (Figs. 3 and 5) of the upward and downward movements of the counter punch 10 defined by the guides 5 and 6.
The drive for pivoting the lower bending punches 19, 20 about the common pivot axis 21 is formed by a pivoting mechanism, which in the instant exemplary embodiment, comprises several pivot drives in the form of rack-and-pinion gears schematically indlcated at 24 in Figs. 1 to 3, distributed over the width of the ` - 8 - 21~5~7 bending machine 1. In detail, a respective circular arc-shaped toothed rack or rail 61, 62 is fixed to the lower region of the respective lower bending punch 19 or 20, respectively, as is also apparent from Figs. 8 and 9 in addition to Figs. 1 to 3. These ~-toothed racks or segments 61, 62, mesh with e.g. equally large toothed wheels 63 and 64 respectively seated on shafts 27 and 28 that are parallel to each other and to the bending punches 19, 20.
The two shafts 27, 28 each are driven by a - for instance, electric - drive motor 72, 73, optionally via a gear not illustrated, as is apparent from Fig. 1. The two shafts 27, 28 extend over the total width of the bending machine 1 and are rotatably journalled on the frame 2 in appropriate baaring parts 75 to be explained in more detail hereinafter, on the end faces as well as on intermediate points in the region of the individual rack-and-pinion gears 24. For each toothed rack gear 24, there is provided a toothed rack 61 and 62 as well as a toothed wheel 63 and 64 mounted on the respective shaft 27 and 28, respectively, for rotation therewith, and, as already pointed out above, several such rack-and-pinion gears 24 are distributedly provided over the width of the bending machine 1 as pivot drives in order to be able to apply the driving torque in a distributed manner. Therefore, with the shafts 27, 28 being rotationally driven, the toothed racks 61, 62 are moved according to a circular arc-shaped path whose centre is located on the pivot axis 21, pivoting apart the lower bending punches 19, 20 connected to them in the way of straddling apart, cf., in particular, Fig. 5 (inoperative position) as well as Figs. 6 and 7 (pivoted apart working position).
Several bearing parts 75 extending transversely to a stationary cross beam 74 of the frame 2 are fixed to the cross beam 74 on the sites of the rack-and-pinion gears 24 in a manner distributed over the machine width for mounting the shafts 27, 28, on the one hand, and the bending punches 19, 20, on the other hand, on the frame 2 as indicated above. These bearing parts 75, on the one hand, i~clude bearings 77 that are exchangeable through removable bearings lids 76 (cf. Figs. 2 and 3~ for the shafts 27, 28, and, on the other hand, are provided with circular arc-shaped slide grooves 78 on both sides in their upper regions (rf. Fig. 2, .. . : .
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~ 9 2105~7 right side), in which the circular arc-shaped toothed racks or toothed segments 61, 62 are slidably guided by means of correspondingly curved guiding keys or ledges 79 provided on them.
Thus, two toothed segments 61, 62 are each slidably guided on such a bearing part 75, one for the shaft 27 and the other for the shaft 28. By means of this bearing arrangement comprising the comparatively firmly constructed toothed racks 61, 62, their guiding keys 79, the circular arc-shaped slide grooves 78 and the bearing parts 75, the load is absorbed in a manner distributed over the machine width such that the forces occurring in bending and to be absorbed are introduced into the frame 2 and its cross beam 74 also in a distributed manner. Thus,the relatively not very massive construction of the bearing parts 75 will do.
It should be mentioned that in the illustration of Fig. 3, only the pinion 63 associated with the shaft 27 can be seen, which, as illustrated, is located in front of the bearing part 75 also in Figs. 1 and 2, and the pinion 64 associated with the shaft 28 and located behind this bearing part 75 accordingly is indicated by a broken line in Fig. 3. On the other hand, the bearing 77 for the shaft 28, which is accessible via the bearing lid 78, can be seen from this representation in Fig. 3 at the shaft 28 indicated on the right-hand side, cf. also Fig. 2.
Furthermore, it is apparent from Fig. 3 that the two shafts 27, 28 are designed with cross-sections having the form of what is called a "lobed cylinder" in order to be able to receive the pinions 63, 64 in a rotationally fixed manner without weakening the cross , section, such as, for instance, in the case of a key-key way connection. The respective bending punch 19, 20, with the pertaining toothed segment 61, 62, respectively, may, for instance, be received in a simple plug-in seat or press-in seat between seat pro~ections 80, 81 formed integral with the respective toothed segment 6~, 62, cf. Figs. 8 and 9 in addition to Fig. 3, but it may also be screwed therewith.
From Figs~ 2 and 3 it is apparent that the two bending punches 19, 20 are,articulatedly connected along their upper inner edges by a hinge ~oint connection over the entire working width.
According to Fig. 4, intermeshing hinge eyes 52 are provided, through which a hinge pin 54 extends in the assembled state. This -..... . , ~ . . . , : ~ ................ ., ,,. ~ . . :.
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2105~`~7 hinge joint connection 53, with the hinge pin 54, defines the aforementioned pivot axis 21 about which the two bending punches 19, 20 are pivoted in operation.
In detail, the bending punches 19, 20 are designed as tool-holders including separately removable and exchangeable tool segments 55, which tool segments 55 are articulatedly connected in pairs by the hinge pins 54 each adapted accordingly in terms of length. These tool segments 55 are retained in the bending punches 19, 20 functioning as toolholders by a simple plug-in connection comprising a longitudinal tongue 82 and a pertaining groove 83 such that the tool segments 55 can be exchanged in a particularly simple and quick manner. It has been found that, surprisingly, no fixed connection is required between the individual tool segments 55 and the respective toolholder or bending punch 19, 20, which also goes back to the fact that, duxing operation, of the forces occurring during bending, the horizontal components are compensated for, at least substantially, by the hinge joint 53 such that only vertical forces or forces acting in the plane of the bending punches 19, 20 are transmitted by the plug-in connection (tongue 82, groove 83), which is readily feasible by means of this tongue-and-groove connection 82, 83. In view of the wear occurring during operation, it may, however, be suitable to provide tool inserts 85 which apply the bending work proper to the sheet via contact zones 84 (cf. Fig. 8 in addition to Figs. 3 and 4), which inserts 85, for instance, are comprised of hard metal inserts to be screwed to the tool segments 55 - or to the bending punches 19, 20, respectively - by bolts 86, cf. Fig. 8. A modified insert design additionally including a tongue-and-groove-connection 87 for the hard metal insert 85 is represented in Fig.
9. In Figs. 8 and 9, furthermore the tool segments 55 (according to Figs. 1 to 7) are indicated in bro~en lines ; in this case, the inserts 85 may be segmented in accordance with the tool segments 55.
In the following, the mode of functioning of the sheet bending machlne 1 will be explained by way of the schema~tic illustration o~ Figs. 5 to 7 as well as with reference to Figs. 2 and 3 (in which the left bending punch 19 is shown in the pivoted state).
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2~ 7 The starting or at-rest position of the sheet bending machine 1 is illustrated in full lines in Fig. 5. The upper counter-punch 10 has assumed its resting position lifted off the sheet 18, and in this position a metal sheet 18 to be bent can be fed manually , or automatically to the bending machine 1 and positioned there.
`~ When a sheet bending cycle is started, the counter-punch 10 at first is moved downwards by means of the spindle drives 14 (Fig.
', 1) until it contacts the sheet 18 to be bent and positioned on the lower bending punches 19, 20, by its edge 13. This phase, in which the sheet 18 is virtually clamped between the three punches or tools 10, 19 and 20, also is illustrated in Fig. 5 with the counter-punch 10 shown in broken lines.
After this, the drive to the driving shafts 27, 28 of the rack-and-pinion drive 24 for the lower bending punches 19, 20 is switched on. Accordingly, the toothed racks 61, 62 are driven along the slide grooves 78 (Fig. 3), pivoting the bending punches 19, 20 about their common pivot axis 21 in opposite senses, i.e., according to the illustrations in Figs. 5 and 6, the left bending punch 19 is pivoted in clockwise direction and the right bending ~ punch 20 is pivoted in counter-clockwise direction. By aid of the `1 pivoting lower tools 19, 20, the sheet 18 at first, e.g., is symmetrically bent, bearing against the lower edge 13 of the upper counter-punch 10, a bending edge 22 thus being produced, cf. Fig.
6. Suitably, the counter-punch 10 is fixed or blocked in its position during this bending procedure, for instance, by means of the spindle drives 14 (Fig. 1) themselves, such that it ~ constitutes a stationary counter-holder during this bending 1 operation. The sheet 18 is bent along the bending edge 22, e.g., by about 90, cf. Fig. 6; as is, furthermore, illustrated in Fig.
7, also an acute bend angle may be realized in the sheet 18. If the sheet 18 has already been subjected to a bending operation, see the bent edge 34 in Figs. 5 to 7, the so-called "collision case~ may occur, in which the bent edge 34 strikes against the counter-punch 10 during bending. In order to prevent undesired deformations in the. sheet 18 when further driving the bending ~j punches 19, 20, the upper counter-punch 10 could, for instance, be l mounted pivotably about a horizontal axis so as to be able to i~ evade when struck by the edge 34. In order to obviate for the ..
2 1 ~ 7 ~ 12 -counter-punch 10, the pivot bearings required in this case, a different solution may be provided for this collision case, it being advantageous that a force balance is provided by the hinge joint; therefore, asymmetric modes of operation are premissible in addition to the described mode of operation in which the lower bending punches 19, 20 are driven symmetrically in opposite directions, in particular at equal angular speeds, since, on the whole, there remains only a relatively small resultant horizontal component. In this regard, independent pivot drives are preferably associated with the two bending punches 19, 20 in the present l sheet bending machine 1, by the separate drive motors 72, 73 and the shafts 27, 28 driven by them in the instant exemplary j embodiment. Conseguently, if the sheet edge 34 strikes against one ~, side of the counter-punch 10 in the collision case described, cf.Fig. 7, the bending punch 20 being on that side is stopped and only the other bending punch 19 is pivoted further in order to continue the bending operation on the sheet 18, as illustrated in l Fig. 7.
i However, it would also be conceivable instead, to pivot the ~ two bending punches 19, 20 from the start (Fig. 5) at different ,' speeds in order to reach the final position, for instance according to Fig. 7, in a continuous operation.
It would also be possible, after the situation shown in Fig.
] 7 has been reached, for the counter-punch 10 to be moved upwards i~ out of the sheet profile 18, whereupon the two bending punches 19, 20 are pivoted further upwardly in the manner of straddling, thus 7 producing a fold in the region of the bending edge 22 realized, i.e., the sheet edge on the left side in Fig. 7 would then be applied directly against the remaining sheet 18. For this bending ? phase, the friction forces applied on the sheet by these contact zones 84 turned out to suffice for holding the largely bent sheet 18 between the bending punches 19, 20 without the counter-punch 10 being required therefor.
, With the present bending machine 1, it is also important forZ the commencing bending operstion, cf. Figs. 5 and 6, that the i sheet contacting zones 84 described, which in the at-rest position of the bending punches 19, 20 (Fig. 5) define the bearing or seating plane 91 for the sheet 18, pass over into the hinge ~oint ` - 13 ~
53 via a depression 90. As bending commences, these depressions 90 provide room to the sheet 18 in the region of the bending ed~e 22 to be produced such that the sheet 18 will not be sque~zed there, as could be the case with adjacent bending punches flat on their upper surfaces. Moreover, it is apparent from Fig. 5 that the hinge pin or pivot axis 21 extends slightly below the sheet contact plane 91 defined by the contact zones 84 (i.e., the lower side of the sheet 18 in Fig. 5), whereby a favourable lever arm is created for transmitting the bending moment onto the sheet 18 in the commencing bending operation.
After completion of the bending operation, the several drives for the punches 10, 19, 20 are reversed in order to pivot the lower bending punches 19, 20 back into the vertical starting position according to Fig. 5 and to move the upper counter-punch 10 upwardly (unless done so far). The bent sheet 18 then may be brought into the subsequent bending position or may be removed from the bending machine 1.
In Figs. 10 to 13, a further sheet bending device 1 is schematically illustrated with its essential working components, completely corresponding to the previously described exemplary embodiment with regard to the relative movement of its punches or tools 10, 19, 20, wherein, however, during the bending process it is not the upper counter-punch 10 that is held stationarily, but one lower bending punch, according to Figs. 10 to 13 the right lower bending punch 20, whereas the other lower bending punch 19 during bending of the sheet 18 (cf. Figs. 11 to 13) is pivoted in correspondence with the previous exemplary embodiments and, moreover, the upper, counter-punch 10 - to induce the relative pivotal movements between the punches - preferably is pivoted at half the angular speed as compared to the left lower bending punch 19, see also the intermediate position of the three punches shown in Fig. 12 as well as the final position shown in Fig. 13. If, with this embodiment according to Figs. 10 to 13, the movement cycle were observed from the upper, counter-punch 10 (at-rest position), a pivotal-movement cycle similar to that previously explained by way of Figs. 1 to 9 would result. In Figs. 10 to 13, however, the individual phases of movement are shown as observed from the stationary frame (which is not illustrated in detail in .- ~ . . . ~ . ';
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.. . .. . . .
210~587 Figs. 10 to 13). A kinematic system of the type as at the bending machine of Figs. 10 to 13 may be desired if only a slight movement, if any, is to be performed on the sheet 18 to be bent on the one side of the bending edge.
More in detail, in the exemplary embodiment illustrated in Figs. 10 to 13, the two lower bending punches 19, 20 again are articulatedly connected by interengaging eye members 52 to form the hinge joint 53, a hinge pin 54 extending through the entire hinge assembly. Laterally of the hinge ~oint 53, the two bending punches 19, 20 have a rounded cheek form where they contact the sheet 18 to be bent. With a view to an easy exchange, the two bending punohes 19, 20 are also assembled of individual tool segments 55, which are firmly connected with a toolholder or punch lower part 56, for instance, by means of bolts 57. As the pivot drive for the left lower punch 19, circular arc-shaped guide rails 58 provided with teeth on the lower side, which are not illustrated in detail, may be provided, extending through guiding slits 59 in the base part 56 of the other bending punch 20 and meshing with driving toothed wheels 60, which basically correspond to the toothed wheels 63 and 64 according to Figs. 1 to 9. The drive for these toothed wheels 60 may be effected via a drive motor not illustrated in detail and a gear in the manner already described in connection with Figs. 1 to 9.
Fig. 10 also schematically indicates in broken lines how the left punch 19 is pivoted outwardly, i.e., away from the right punch 20, as the toothed wheel 60 is rotated in the counter-clockwise direction (see arrow). For reasons of simplicity, it is not shown that, simultaneously with this pivotal movement of the one lower punch 19, also the upper punch 10 is pivoted -preferably at half the angular speed of the lower punch 19 as mentioned before.
The drive of the upper punch-10 basically may be effected in a manner analogous to that of the lower punch 19, the preferred transmission ratio of 2 : 1 being ensured by means of a gear. Such a drive assembly is conventional per se and need not be discussed here in detail.
Furthermore, it should be noted that the mounting of the upper punch 10 in the frame not illustrated in detail, with the .
.
2~5~7 ~s - 15 -bending machine according to Fig. 10, basically may be realized in a manner similar to that previously discussed by way of Fig. 1, i.e., in particular, with end-side main supports 3, 4, which, however, would have to be mounted pivotably on the lower frame 2, e.g., together with the spindle drives (14 in Fig. 1) or similar drives, which may be effected in a manner known to a person , skilled in the art.
In Figs. 11 to 13, the pivot axis 21 for the relative pivotal movement between the lower bending punches 19, 20 is illustrated, which, in this case, coincides with the geometrical axis of the hinge pin 54 of the hinge joint 53 (Fig. 10). During bending, also the upper punch 10 is pivoted about this pivot axis 21, cf.
illustration in Figs. 12 and 13.
~ he centre of the circular arc-shaped rails 58 is, of course, located on this pivot axis 21 (i.e., on the geometric axis of the hinge joint axis 54).
Although the invention has been explained in detailed manner by way of particularly preferred exemplary embodiments, other variants and modifications are feasible within the scope of the invention. Thus, it is, for instance, possible to provide the hinge joint connection 53 described in respect of Figs. 1 to 9 with a throughgoing hinge pin 54 having a length corresponding to the machine width. On the other hand, it is also possible with the distributedly arranged hinge joints, cf. Fig. 4, to allow the respective hinge pins 54 to pro~ect slightly beyond the tool segment pairs 55 on one side and to reach into the hinge eyes 52 of the consecutive pair of tool segments 55 in a manner that a connection between the individual tool segment pairs will be obtained.
Furthermore, instead of the described vertical orientation of the bending machine 1 with the sheet 18 to be bent having to be disposed horizontally, any other orientation, such as a substantially inclined one, may be chosen with the sheet 18 being positioned accordingly inclined in the starting position. For this purpose, only the frame parts would have to be modified accordingly.
Appropriate elec~ric control circuits can be provided for the drive motors, for instance, for the drive motors 72, 73 for , . ~ .
! . ' ; ,;; i 21U~7 pivoting the bending punches 19, 20 as well as for the drive motors for the two spindle drives 14, in order to be able to switch these drive ~otors on and off as required. In principle, these electrical drive motors may, of course, be replaced with hydraulic motors or pressure fluid cylinders.
In addition, it is possible to move the upper punch 10 up and down for instance by means of an eccentric drive or a working cylinder, wherein locking of the upper punch 10 in the lower working position, e.g., according to Figs. 2, 3, 6 and 7, if desired, may be obtained by simply stopping the eccentric drive in this position.
In a practical exemplary embodiment according to Fig. 1, the machine width was 1,500 mm, the length of the tool segments 55 was 125 mm, and the diameter of the hinge pin 54 was 8 mm; the pitch for the pivot drives 24 was 400 mm, the external drive units each having been offset relative to the end sides of the machine 1 by about 150 mm. The total mass of the bending machine 1 a~ounted to less than 500 kg, and 2 mm thick sheets could be bent without difficulty.
, ..:
Claims (13)
1. A sheet bending machine (1) comprising three punches (19, 20, 10), i.e. two adjacently arranged and pivotally interconnected bending punches (19, 20) defining a sheet bearing plane (91) with sheet contacting zones (84) in the at-rest position, and a counter-punch (10) located opposite the bending punches (19, 20) and linearly movable between a working position at the sheet (18) and a retracted position, wherein two punches (19, 20; 10, 19) are pivotably mounted and are each coupled with a pivot drive (24), and wherein the sheet (18) is bent about the counter-punch (10) in the working position by pivoting at least one of the bending punches (19, 20), characterised in that the two bending punches (19, 20), along their edges facing each other in the at-rest position, are directly connected with each other over the width of the bending machine (1) by a hinge joint connection (53) offset from the sheet bearing plane (91), a depression (90) being provided in each bending punch (19, 20) between the sheet contacting zone (84) of the bending punch (19, 20) and the hinge joint connection (53), and in that the bending punches (19, 20) are equipped with detachable tool segments (55) adjacently arranged over the width of the bending machine (1), which tool segments are interconnected in pairs by hinge joint connections, the hinge joint connection (53) of the bending punches (19, 20) being formed by the hinge joint connections of all the tool segment pairs.
2. A bending machine according to claim 1, characterised in that, distributed over the width of the bending machine (1), several pivot drives (24) engage at each of the two independently pivotable bending punches (19, 20), and the counter-punch (10) is only linearly movable.
3. A bending machine according to claim 2, characterised in that the counter-punch (10) is designed to be retractable from the bending punches (19, 20) so as to enable folding of the sheet (18) in the final phase of bending of the sheet (18).
4. A bending machine according to claim 1, characterised in that one of the bending punches (20) is stationarily mounted and the other bending punch (19) as well as the counter-punch (10) are pivotably mounted, the pivotable bending punch (19) being drivable at twice the angular speed of the counter-punch (10).
5. A bending machine according to any of claims 1 to 4, characterised in that the tool segments (55) are held on the bending punches (19, 20) which then serve as toolholders, on the side located opposite the sheet contacting zones (84) by means of a simple plug-in connection (82, 83), e.g. a tongue-and-groove connection.
6. A bending machine according to any of claims 1 to 5, characterised in that the tool segment pairs are provided with separate hinge pins (54) adapted to the length of the segments.
7. A bending machine according to claim 6, characterised in that on one side the hinge pins (54) of the tool segments each project into the hinge eyes (52) of the adjacent tool segment pair.
8. A bending machine according to any of claims 1 to 5, characterised in that a common continuous hinge pin (54) extending through all the tool segments (55) is provided.
9. A bending machine according to any of claims 1 to 8, characterised in that the tool segments (55) are provided with separate inserts (85) forming the sheet contacting zones (84).
10. A bending machine according to claim 9, characterised in that the inserts (85) are screwed to the tool segments (55).
11. A bending machine according to any of claims 1 to 10, characterised in that a circular arc-shaped toothed rail (61, 62;
58) is provided as each pivot drive, which is firmly connected with the associated, bending punch (19, 20; 19) and which is driven by a pinion (63, 64, 60) mounted on a shaft (27, 28).
58) is provided as each pivot drive, which is firmly connected with the associated, bending punch (19, 20; 19) and which is driven by a pinion (63, 64, 60) mounted on a shaft (27, 28).
12. A bending machine according to claim 11, characterised in that the toothed rail (61, 62) is mounted in a circular arc-shaped bearing, e.g., in a bearing groove (78) on a stationary bearing part (75) mounted on the frame (2).
13. A bending machine according to claim 11 or 12, characterised in that two separate electric motors (72, 73) are provided for rotatably driving the two shafts (27, 28) associated with the bending punches (19, 20).
Applications Claiming Priority (4)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| PCT/AT1991/000044 WO1991013704A1 (en) | 1990-03-15 | 1991-03-14 | Sheet-metal bending device |
| WOPCT/AT91/00044 | 1991-03-14 | ||
| AT1878/91 | 1991-09-18 | ||
| AT187891 | 1991-09-18 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2105587A1 true CA2105587A1 (en) | 1992-09-15 |
Family
ID=3522971
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA002105587A Abandoned CA2105587A1 (en) | 1991-03-14 | 1992-03-11 | Sheet bending machine |
Country Status (16)
| Country | Link |
|---|---|
| EP (1) | EP0575393B1 (en) |
| JP (1) | JP2672402B2 (en) |
| KR (1) | KR960007488B1 (en) |
| CN (1) | CN1045731C (en) |
| AR (1) | AR246448A1 (en) |
| AT (1) | ATE115014T1 (en) |
| AU (1) | AU657312B2 (en) |
| BR (1) | BR9205777A (en) |
| CA (1) | CA2105587A1 (en) |
| CZ (1) | CZ283115B6 (en) |
| DE (1) | DE59200920D1 (en) |
| DK (1) | DK0575393T3 (en) |
| ES (1) | ES2065177T3 (en) |
| HU (1) | HU215986B (en) |
| SK (1) | SK279575B6 (en) |
| WO (1) | WO1992016319A1 (en) |
Families Citing this family (14)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP1411404B1 (en) * | 2002-10-18 | 2006-08-16 | Schechtl Maschinenbau GmbH | Bending machine and bending machine control method |
| CN102430617B (en) * | 2011-11-03 | 2014-11-05 | 湖北三江航天万山特种车辆有限公司 | Processing device for large fillets of metal plates |
| KR101533739B1 (en) * | 2015-01-22 | 2015-07-03 | 주식회사 일우산업기계 | Multi-function folding device |
| CN106216448B (en) * | 2016-08-05 | 2018-01-09 | 乐清市敏捷机械有限公司 | The Bending Processing method of hydraulic power unit fuel tank side board |
| CN107030198A (en) * | 2016-12-27 | 2017-08-11 | 安徽省青阳县华瑞科技有限公司 | A kind of support-folding mould |
| DE102017006218A1 (en) | 2017-06-28 | 2019-01-03 | Technische Universität Dortmund | Apparatus and method for bending sheet-like workpieces with simultaneous pressure stress superposition |
| CN109482678A (en) * | 2018-12-10 | 2019-03-19 | 湖南固可得建筑科技有限公司 | A kind of single plate bidirectional automatic edge folding |
| DE102019008118B4 (en) * | 2019-11-21 | 2022-09-15 | Wolfram Hochstrate | Swivel bending machine, especially for counter bending with a duplex folding beam |
| CN111014366A (en) * | 2020-03-09 | 2020-04-17 | 山东炎黄工业设计有限公司 | Thin plate bending device and using method thereof |
| CN113000716B (en) * | 2021-02-22 | 2023-02-24 | 中车青岛四方机车车辆股份有限公司 | Demoulding device and press with same |
| CN113441956B (en) * | 2021-07-20 | 2023-10-10 | 玖科智造(武汉)精密机械有限公司 | Profile cutting equipment for building engineering |
| CN113333522A (en) * | 2021-08-09 | 2021-09-03 | 新沂市振港金属制品有限公司 | Continuous stamping device of metalworking |
| CN113617890A (en) * | 2021-09-09 | 2021-11-09 | 安徽华汇电力设备有限公司 | Stainless steel plate bending equipment for power distribution cabinet |
| CN115502250B (en) * | 2022-09-26 | 2023-04-14 | 广东百能家居有限公司 | Automatic bending device and method for stainless steel cabinet plate |
Family Cites Families (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3044526A (en) * | 1960-02-15 | 1962-07-17 | Percy L Cady Jr | Brake for forming metal plate and sheet |
| US3845655A (en) * | 1972-09-18 | 1974-11-05 | Widder Corp | Press brakes |
| US3877279A (en) * | 1972-10-30 | 1975-04-15 | Mark Products Corp Van | Sheet metal brake |
| US4282735A (en) * | 1979-04-02 | 1981-08-11 | Van Mark Products Corporation | Brake for sheet metal or the like |
| AT393639B (en) * | 1990-03-15 | 1991-11-25 | Lift Verkaufsgeraete Gmbh | SHEET BENDING DEVICE |
-
1991
- 1991-03-14 BR BR9205777A patent/BR9205777A/en not_active IP Right Cessation
-
1992
- 1992-03-11 CA CA002105587A patent/CA2105587A1/en not_active Abandoned
- 1992-03-11 CZ CS931860A patent/CZ283115B6/en not_active IP Right Cessation
- 1992-03-11 HU HU9302585A patent/HU215986B/en not_active IP Right Cessation
- 1992-03-11 KR KR1019930702747A patent/KR960007488B1/en not_active IP Right Cessation
- 1992-03-11 AU AU13491/92A patent/AU657312B2/en not_active Ceased
- 1992-03-11 SK SK981-93A patent/SK279575B6/en unknown
- 1992-03-11 ES ES92906012T patent/ES2065177T3/en not_active Expired - Lifetime
- 1992-03-11 DK DK92906012.7T patent/DK0575393T3/en not_active Application Discontinuation
- 1992-03-11 WO PCT/AT1992/000032 patent/WO1992016319A1/en active IP Right Grant
- 1992-03-11 AT AT92906012T patent/ATE115014T1/en not_active IP Right Cessation
- 1992-03-11 DE DE59200920T patent/DE59200920D1/en not_active Expired - Fee Related
- 1992-03-11 JP JP4505883A patent/JP2672402B2/en not_active Expired - Lifetime
- 1992-03-11 EP EP92906012A patent/EP0575393B1/en not_active Expired - Lifetime
- 1992-03-13 CN CN92101602A patent/CN1045731C/en not_active Expired - Fee Related
- 1992-03-13 AR AR92321920A patent/AR246448A1/en active
Also Published As
| Publication number | Publication date |
|---|---|
| CN1045731C (en) | 1999-10-20 |
| JP2672402B2 (en) | 1997-11-05 |
| SK279575B6 (en) | 1999-01-11 |
| HU9302585D0 (en) | 1993-12-28 |
| WO1992016319A1 (en) | 1992-10-01 |
| JPH06505677A (en) | 1994-06-30 |
| HUT64492A (en) | 1994-01-28 |
| BR9205777A (en) | 1994-04-26 |
| AU657312B2 (en) | 1995-03-09 |
| AU1349192A (en) | 1992-10-21 |
| DE59200920D1 (en) | 1995-01-19 |
| ATE115014T1 (en) | 1994-12-15 |
| DK0575393T3 (en) | 1995-05-01 |
| HU215986B (en) | 1999-03-29 |
| ES2065177T3 (en) | 1995-02-01 |
| CN1064632A (en) | 1992-09-23 |
| CZ186093A3 (en) | 1994-03-16 |
| EP0575393B1 (en) | 1994-12-07 |
| CZ283115B6 (en) | 1998-01-14 |
| EP0575393A1 (en) | 1993-12-29 |
| KR960007488B1 (en) | 1996-06-05 |
| AR246448A1 (en) | 1994-08-31 |
| SK98193A3 (en) | 1994-01-12 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| FZDE | Discontinued |