EP0338949A1 - Bending machine for sheet metal - Google Patents

Abstract

Plate metalworking. <??>The sheet metal bending machine is characterised in that: .the moveable component is a carriage (32) which can be moved in a cradle defining the support and guiding channel (31) which has the shape of a concave cylindrical casing portion open in the direction of the shoes, .the channel is carried by a frame (20) suspended on the holder (3) by means (23, 24) for adjusting the vertical and horizontal positions, .and the flap (41) comprises a radial plane of symmetry (P') passing through the centre (C) of the casing portion and possesses a bending head (44) having a symmetrical profile, on either side of the said plane. <??>Application to the machines for producing either positive or negative bends. <IMAGE>

Description

The present invention relates to the technical field of sheet metal folding, with a view to producing articles, products or panels having, at least locally, successions of folds which may be positive or negative, depending on the local conformation to be obtained, the mechanical resistance conferred and / or the subsequent treatments applied.

In the above technical field, the prior art has proposed a number of solutions for performing folds in a metal sheet or sheet.

The first technique calls for the existence of a blade which is driven in displacement, rectilinear or curved, tangentially to folding beaks formed by a bed base and a blank holding shoe immobilizing the sheet to be bent. Such a technique is illustrated by patent EP 0 023 894 and patent EP 0 077 314 .

Folding by a blade moved tangentially to the folding spout of the bed base and blank holder is characterized by a sliding of the blade which is responsible for marking the sheet. Such a process cannot be envisaged when it is a question of working sheets having, a priori, a surface condition which must be respected and resulting, for example, from a surface polish, a lacquering or any other application or surface treatment.

In addition to this drawback, it should be noted that machines of the blade type generally have only one direction of work, so that it is necessary to turn over the blank or the sheet to be folded, whenever appropriate. reverse the folding direction.

In an attempt to reduce this drawback, it has been proposed, in particular by patent EP 0 022 122 , to provide a folding machine with two superimposed folding blades, arranged on either side of the plane for immobilizing and clamping the blank or a sheet between the box spring and the blank holder shoe. Such a proposal undoubtedly eliminates the disadvantage of turning over the blank or the sheet. However, the operating principle of such a machine allows the displacement to remain relative of one or the other of the blades, so that the folded sheet undergoes the same surface attacks, responsible for a marking corresponding to the relative sliding with respect to the folding radius.

The techniques for manufacturing articles, products or objects, from folded sheets, previously treated on the surface by any suitable operation, preclude the use of such machines or processes which do not lead to the obtaining impeccable finished products.

The prior art knows another family of folding machines, in which the member responsible for folding the blank consists of a flap capable of being rotated on an axis parallel to that of the folding spouts.

Such a technique can be considered as illustrated by patent FR 2 236 992 ( 75-40 066 ) of which it seems likely that the constructive structure retained always involves the reversal of the blank or of the sheet, for the execution of successive folds of different orientations, for example positive and negative.

The prior art also knows, in this second type of machine, a proposal illustrated by patent FR 2 502 518 ( 81-06 573 ).

According to the brief and incomplete teaching provided by this patent, it would appear that the folding of a blank is conducted, by means of a pivoting flap, capable of being displaced, by rotation about an axis parallel to the plane clamping, from a horizontal position, downwards for the execution of a negative fold and, from a vertical position to a horizontal position, for the execution of a positive fold.

If such a proposal may appear as an improvement on the previous technique, due to the possibility of successively executing folds of different orientations, on the other hand, it should be noted that the means used do not allow marking to be removed sheet metal or blank by the action of the shutter which is always responsible for the execution of streaks or scratches prejudicial to the surface treatment, previously imposed on the blank or sheet metal.

Furthermore, the teaching disclosed does not provide any details as to the means used to allow the bypassing of the folds executed by the movable flap, when it is necessary to carry out a succession of reverse folds for which it is important to have the movable flap on either side of the clamping and holding plane of the blank or of the sheet.

Moreover, it illustrated should be noted that the technical arrangements do not, apparently, achieve the performance of folds on angles greater than 90 ^o, which appears a clear need in the current technical achievement by bending elements constituting metallic structures, more or less complex, from blanks or thin sheets which should be stiffened and reinforced by the presence of folds.

Also known from US-A-4,043,165 is a sheet metal bending machine comprising two members arranged symmetrically and ensuring both clamping and folding. These members, in the form of hollow profile bars, are mounted to rotate on a pair of discs.

This machine has the drawbacks already mentioned on the machines of the prior art and does not allow several successive folds to be produced. The chosen arrangement is also a source of tension and deformation of the sheet for the sheet to be bent.

It is also known from patent DE-C-288 029 to guide a folding cheek in a concave guideway. This device and, in particular, the folding member is, however, not designed to produce positive and negative folds.

US-A-3,786,666 discloses the use of a folding flap supported by disks which can be moved on a track made up of rollers. This device does not, either, to achieve positive and negative folds, the technique used more like stamping techniques.

The present invention aims to provide a solution to the above problems, still unsolved by the known prior art. The object of the present invention is to provide a structure of a folding machine, of the flap type, making it possible to produce, at will, without turning the blank or the sheet, successively positive and / or negative folds, capable of have bending angles less than, equal to or greater than 90 ^o .

Another object of the invention is to propose a structure of a folding machine making it possible, by simple transfer or translation of the blank or sheet, of successive folds, of complex and combined natures, which can be easily circumvented in their envelope d 'size, through the active tools of the machine, able to be brought into the required position for the execution of a fold following those already made.

Another objective of the present invention is to propose means allowing the execution of successive folds in any order and in any direction, without resulting in marking, scratching or other degradation of the one or other of the sides of the blank or of the sheet to be folded, by means of the rotary shutter.

Another object of the invention is to provide a new machine whose ability to execute, without turning the blank or the sheet, folds, whether positive or negative, makes it possible to integrate into an automatic chain or working line. fully automated and capable of having the work parameters changed quickly and easily to give it a certain degree of flexibility.

To achieve the above objectives, the sheet bending machine according to the invention, of the type comprising a movable frame carrying, on the one hand, a fixed base supporting a fixed lower shoe forming a folding spout, on the other hand , in a plane superimposed on the bed base, a closing-opening kneepad carrying a blank holder shoe forming a folding spout oriented parallel to and in the same direction as that of the lower shoe and arranged directly above the latter and, moreover, facing the spouts, a flap extending parallel to said spouts , capable of being pivotally controlled on an axis of rotation parallel to the spouts and carried by a member movable along a support and guide track in the form of an envelope whose geometric center is located near the spouts, is characterized in that :
the movable member is a carriage movable in a cradle defining the support and guide track which is in the form of a portion of concave cylindrical envelope, open in the direction of the shoes,
- the track is carried by a chassis suspended on the frame by means of adjustment in vertical and horizontal positions,
- And the flap has a radial plane of symmetry passing through the center of the envelope portion and has a folding head having a symmetrical profile, on either side of said plane.

• La fig. 1 est une coupe-élévation schématique d'une machine à plier conforme à l'invention.
• La fig. 2 est une coupe-élévation partielle montrant, à plus grande échelle, un détail de réalisation de la machine.
• La fig. 2A est une coupe-élévation d'une variante de réalisation de l'organe selon la fig. 2.
• La fig. 3 est une vue schématique illustrant une position caractéristique de fonctionnement des éléments constitutifs de la machine.
• La fig. 4 est une coupe-élévation partielle montrant, à plus grande échelle, un détail de fonctionnement de la machine selon la séquence de la fig. 3.
• La fig. 5 est une coupe-élévation schématique, analogue à la fig. 4 illustrant une autre séquence de fonctionnement.
• La fig. 6 est une coupe-élévation à plus grande échelle, analogue à la fig. 4, mettant en évidence le même principe de fonctionnement en relation avec la fig. 5.
• Les fig. 7 et 8 sont des coupes-élévations schématiques illustrant deux autres positions caractéristiques de fonctionnement, en relation avec les séquences selon les fig. 3 et 5.
• Les fig. 9 à 14 sont des vues schématiques illustrant certaines possibilités de réalisation à partir de la machine selon l'invention.

Various other characteristics will emerge from the description given below with reference to the appended drawings which show, by way of nonlimiting examples, embodiments of the subject of the invention.

• Fig. 1 is a schematic sectional elevation of a folding machine according to the invention.
• Fig. 2 is a partial sectional elevation showing, on a larger scale, a detail of embodiment of the machine.
• Fig. 2A is a sectional elevation of an alternative embodiment of the member according to FIG. 2 .
• Fig. 3 is a schematic view illustrating a characteristic operating position of the components of the machine.
• Fig. 4 is a partial sectional elevation showing, on a larger scale, a detail of operation of the machine according to the sequence of fig. 3 .
• Fig. 5 is a schematic sectional elevation, similar to FIG. 4 illustrating another operating sequence.
• Fig. 6 is a sectional elevation on a larger scale, similar to FIG. 4 , highlighting the same operating principle in relation to FIG. 5 .
• Figs. 7 and 8 are schematic sectional elevations illustrating two other characteristic operating positions, in relation to the sequences according to FIGS. 3 and 5 .
• Figs. 9 to 14 are schematic views illustrating certain possible embodiments from the machine according to the invention.

The folding machine according to the invention comprises, as appears in FIG. 1 , a bench 1 delimiting a guide path 2 in rectilinear movement for a movable frame 3 supporting the main bodies for taking up and folding a sheet or blank 4 arranged flat according to a layout plan and transfer P horizontal.

The movable frame 3 comprises, on the front, a box spring 5 rising vertically from the base and carrying a fixed lower shoe 6 . As shown in fig. 2 , the shoe 6 forms a folding spout 7 extending horizontally towards the interior of the machine. The spout 7 has a folding edge 8 which is determined by a fillet or a rounding centered on a winding and folding axis 9 parallel to the plane P.

The frame 3 supports, by its superstructure and in a vertical plane superimposed on the bed 5 , a toggle 10 , called opening and closing. The toggle joint 10 is constituted, in known manner, by a movable apron 11 suspended from the superstructure of the frame 3 by a plurality of articulated parallelograms 12 associated with one or more actuating jacks 13 . The toggle joint 10 is formed so that the deck 11 can be moved vertically, in one or the other direction of the arrow f₁ , relative to the bed base 5 . Apron 11 carries, at its base, a hold-down shoe 14 disposed directly above the shoe 6 and forming a folding spout 15 extending parallel to and in the same direction as the spout 7 . The folding spout 15 comprises a folding edge 16 constituted by a rounded or a fillet centered on a winding axis 17 parallel to the plane P.

The frame 3 supports, behind the facade and in the direction of the spouts 7 and 15 , a movable frame 20 which is suspended by means of two articulation axes, respectively 21 and 22 . The articulation axis 21 extends horizontally, parallel to the plane of the spouts 7 and 15 and is located at the upper part of the movable frame 3 , being offset rearward relative to the plane containing the bed base 5 and the apron 11 . The suspension of the chassis 20 on the axis 21 is produced by means of a motor member 23 with rectilinear stroke, designed to allow the adjustment of the horizontal position of the chassis 20 . Preferably, as is apparent from FIG. 3 , the drive member 23 is constituted by two jacks 23 a , 23 b , preferably hydraulic, double acting, arranged in opposition in a common body, on either side of a fixed common partition. The cylinders 23 a and 23 b can be supplied selectively for each of the two variable volume chambers which they delimit. The double cylinder 23 is mounted articulated, by one of its rods, on the axis 21 and, by the other, on a pivot or an axis 24 carried by the chassis 20 .

The suspension of the chassis 20 by the axis 22 is ensured so that the latter is located parallel to the axis 21 , being located at a level lower than the latter while occupying, moreover, a position more offset towards the rear. with respect to the common plane of the bed base 5 and the panel 11 . The suspension of the chassis 20 on the axis 22 is ensured with the interposition of a motor member 24 responsible for controlling the movement or the adjustment in the horizontal position of the chassis 20 . The drive member 24 is preferably of the straight-stroke type, such as a hydraulic or pneumatic cylinder. Fig. 1 shows an example of assembly according to which the jack 24 is articulated by an axis 25 on the frame mobile 3 and by an axis 26 on one of the branches of a lifting beam or of a lever 27 articulated by its other branch on the axis 22 . The lifting beam or the lever 27 is connected, in its middle part, by a hinge pin 28 to a rear extension 29 of the chassis 20 .

In its part opposite the extension 29 and facing the folding nozzles 7 and 15 , the chassis 20 forms a cradle 30 defining a guide and rolling track 31 . The track 31 is in the form of a portion of concave cylindrical envelope, open in the direction of the shoes 7 and 15 and whose geometric center C is located near the axes 9 and 17 . Track 31 is used to support a carriage 32 mounted on track 31 with the possibility of rolling, by means of rollers 33 and counter rollers 34 . The carriage 32 has a plane of symmetry P ′ occupying a radial direction centered on the center C of the track 31 . The carriage 32 is coupled to a drive member 35 carried by the chassis 20 . In an exemplary embodiment, the motor member 35 is of the linear type, such as a double-acting hydraulic cylinder whose body 36 is mounted by pins 37 on a stock 38 of the chassis 20 . The piston rod 39 of the jack 35 is articulated directly by a pin 40 on the carriage 32 . The supply of the jack 35 therefore makes it possible, by extension or retraction of the piston rod 39 , to move the carriage along the track 31 , for example in the direction of the arrow f₂ from the position according to fig. 1 and vice versa.

The carriage 32 carries on the plane P ′ a flap 41 capable of occupying an adjustable position, by means of adjustment members, such as screws 42 and one or more shims of thickness 43 . These adjustment members make it possible to adapt the position of the flap 41 as a function, in particular, of the thickness of the sheet or blank to be folded. The flap 41 forms a head 44 extending parallel to the plane P and having, in cross section, a symmetrical profile on either side of the plane of symmetry P ′ . In a preferred embodiment, the profile 45 consists of the presence of two inclined faces 46 a and 46 b , converging towards a flat 47 extending perpendicular to the plane P ′ of symmetry. Preferably, the inclined faces define, respectively, with the plane of symmetry P ′ , an angle α equal to 60 ^o .

Fig. 2 a shows that the profile 45 can also be formed by one or more radii of curvature organized symmetrically, on either side of the plane P ′ .

In all the embodiments, the flap 41 has a head 44 having a length close to or, preferably, equal to that of the folding spouts 7 and 15 .

The folding machine described above works as follows.

Assuming that it is a question of making a positive fold, that is to say folded upward, from a supply or tightening plane P , on a sheet or blank 4 , the flap 41 is placed in the position illustrated in fig. 1, 2 and 4 . The sheet or blank 4 is then placed on the spout 7 , after opening the blank holder 14 by means of the toggle 10 . The sheet or blank is engaged to reach adjustable, retractable depth adjustment stops 50 , which are, for example, controlled by jacks. When the required position is reached, the toggle joint 10 is controlled in the closing stroke, so as to lower the blank holder shoe 14 to pinch the blank or the sheet metal 4 between the spouts 15 and 7 . In such a position, illustrated by FIGS. 2 to 4 , the blank or the sheet 4 extends, by the desired measurement, beyond a fictitious plane P˝ passing through the folding edges or the fillets 8 and 16 of the spouts 7 and 15 .

The drive members 23 and 24 are then controlled, so as to make the center C coincide with the folding axis 17 , so that the plane P ′ of symmetry passes through this axis, as shown in FIGS. 2 and 4 .

The drive member 35 is then supplied to cause the retraction stroke of the rod 39 , so as to urge the movement of the carriage 32 , in the direction of the arrow f₂ , on the track 31 . The head 44 of the flap 41 thus bears on the face lower of the sheet or blank 4 and, by its inclined face 46 b , subjects the latter to a folding by requiring it to be wound on the edge or the edge 16 . The drive member 35 is controlled to impose on the flap 41 a stroke over an angular range corresponding to the folding angle to be respected.

It should be noted that the presence of the folding spout 17 and the particular shape of the head 44 make it possible to achieve positive folding over an angular amplitude greater than 90 ^o . Depending on the embodiment conferred on the sides 46 a and 46 b , folding over an angular value of 0 to 120 ^o can be carried out.

Figs. 5 and 6 show that it is also possible to carry out, in a similar manner, a negative fold, that is to say oriented downward, by initially adjusting the carriage 32 to give it a high starting position, such that the plane of symmetry P ′ passes through axis 9 on which the center C of track 31 is also centered. In such a case, the drive member 35 is then controlled in extension stroke, so that the movement of the carriage 32 , in the opposite direction to that of the arrow f₂ , ensures the winding of the blank 4 on the edge or the edge 8 , over an angular range which can also be comprised between 0 and 120 ^o .

After the execution of a positive fold, as illustrated in fig. 4 , or a negative fold, as illustrated in fig. 6 , the head 44 occupies either the position P₁ or the position P₂ .

When it is necessary to execute a second fold, it is understood that from the positions illustrated in FIGS. 4 and 6 , it should be possible to disengage the head 44 , before advancing the sheet or blank 4 after opening the blank holder shoe 14 . It is also appropriate to make such a clearance, so as to sufficiently erase the head 44 to allow free passage of the fold produced.

The disengagement of the head 44 , after the execution of a positive fold and assuming that it is advisable to then execute in succession a negative fold, is illustrated in FIG. 7 . This clearance is obtained, first of all, by supplying the motor member 24 controlling the recoil in the direction of the arrow f₃ of the chassis 20 and, consequently, of the head 44 , of a measure corresponding to the subsequent advancement to be imposed on the blank 4 .

Then or simultaneously, the drive member 23 is powered to control the release or vertical movement of the chassis 20 in the direction of the arrow f₄ , over a height corresponding, by excess, to that of the fold just executed.

The blank holder shoe 14 can then be ordered to open to allow the transfer or translation of the sheet 4 in the direction of the arrow f₅ , on a measurement corresponding to the spacing to be respected between the first fold produced and the second to execute.

In this position, the drive member 24 is then controlled in the opposite direction to cause the chassis 20 to advance in the opposite direction to the arrow f₃ . The drive member 23 is then controlled to lower the chassis 20 in the opposite direction to the arrow f₄ , in order to cause the plane P ′ to pass through the winding axis 9 , assuming that it is a question of 'then execute, as a second fold, a negative fold.

The execution of this second fold is only ensured, when the center C coincides with the axis 9 , by the supply of the motor member 35 making it possible to control the movement of the carriage 32 in the opposite direction to that of the arrow f₂ , over an angular range corresponding to the amplitude of folding to be executed.

Fig. 8 illustrates an intermediate phase of release of the chassis 1 , occurring after the execution of a negative fold when it is necessary to execute, subsequently, a positive fold on the same blank or the same sheet 4 .

As is apparent from the above, the structure of the machine, involving a chassis suspended from two parallel articulation axes, associated with clean drive members and a guide track in the form of a portion of concave cylindrical casing carrying a swivel carriage supporting a rotary shutter, allow to realize, without turning, automatically or no, any successions of folds, positive and negative, only by controlling the sequential phases of supply of the drive members 23, 24 and 35 . Many possibilities of realization can thus intervene, either by manual control, or by programmed automatic control.

Complex, rapid and serial production ranges can thus be carried out without the intervention of qualified driving or handling personnel, as is necessary with current machines. Furthermore, the only necessary control being that of the supply of the jacks 23 , 24 and 35 , as well as that of the step of advancement of the blank or of the sheet, it becomes possible to operate such a machine with great flexibility, which is an important industrial asset in running a production line.

Given the possibility of making the center C of track 31 coincide with the center or the axis of the fillet or the folding edge concerned, depending on the fold to be executed, it becomes possible to fold, without risk of marking the external surface, any type of sheet metal, possibly pretreated on the surface, by means of the flap 41 only subjected to a rotary movement causing the winding of the sheet metal part or blank to be folded directly on the folding edge.

The execution of successive folds or folding zones, even relatively complex, can thus be provided on blanks or sheets having undergone a final surface treatment, such as polishing, lacquering, anodizing, etc.

Figs. 9 to 14 show, by way of example, possibilities of successive folding which can be programmed with the machine of the invention, without requiring the intervention of a driving staff. These various embodiments allow that it is possible to forward successively and in any order, positive and negative bends, may be of interest angles less variable than or equal to 90 ^o.

Claims (11)

1 - Machine for bending sheets, of the type comprising a movable frame ( 3 ) carrying, on the one hand, a fixed base ( 5 ) supporting a fixed lower shoe ( 6 ) forming a folding spout ( 7 ), on the other part, in a plane superimposed on the bed base, a closing-opening kneepad ( 10 ) carrying a blanking shoe ( 14 ) forming a folding spout ( 15 ) oriented parallel to and in the same direction as that of the bottom shoe and arranged directly above the latter and, moreover, facing the spouts, a flap ( 41 ) extending parallel to said spouts, capable of being pivotally controlled on an axis of rotation parallel to the spouts and carried by a movable member ( 32 ) along a support and guide track ( 31 ) in the form of an envelope whose geometric center ( C ) is located near the spouts ( 7, 15 ),
characterized in that:
the displaceable member is a carriage ( 32 ) displaceable in a cradle defining the support and guide track ( 31 ) which is in the form of a portion of concave cylindrical envelope, open in the direction of the shoes,
the track is carried by a chassis ( 20 ) suspended on the frame ( 3 ) by means ( 23, 24 ) of adjustment in vertical and horizontal positions,
- And the flap ( 41 ) has a radial plane of symmetry ( P ′ ) passing through the center ( C ) of the envelope portion and has a folding head ( 44 ) having a symmetrical profile, on either side of said plan. 2 - Folding machine according to claim 1,
characterized in that the flap ( 41 ) is adjustable in position on the plane of symmetry ( P ′ ). 3 - folding machine according to claim 1 or 2,
characterized in that the flap ( 41 ) has a head ( 44 ) having transversely a symmetrical curved profile on either side of the plane of symmetry ( P ′ ). 4 - folding machine according to claim 1 or 2,
characterized in that the flap ( 41 ) has a head ( 44 ) having a transversely symmetrical profile with respect to the plane and consisting of two inclined faces ( 46 a , 46 b ) and converging in the direction of a flat ( 47 ) perpendicular to the plane of symmetry ( P ′ ). 5 - Folding machine according to claim 4,
characterized in that each section ( 46 ) is inclined relative to the plane of symmetry ( P ) by an angle (α) close to 60 ^o . 6 - Folding machine according to claim 1,
characterized in that the carriage ( 32 ) is mounted on the curved guide track ( 31 ) of a cradle ( 30 ) by means of rollers ( 33 ) and counter-rollers ( 34 ). 7 - Folding machine according to claim 1 or 6,
characterized in that the carriage ( 32 ) is coupled to a moving drive member ( 35 ) carried by the chassis ( 20 ). 8 - Folding machine according to claim 1,
characterized in that the chassis ( 20 ) is suspended from the frame ( 3 ) by two pivot axes ( 21, 22 ) parallel to the folding spouts ( 7, 15 ) with interposition for each of a clean motor member ( 23, 24 ). 9 - Folding machine according to claim 1 or 8,
characterized in that the chassis ( 20 ) is suspended from a first articulation axis ( 21 ) superimposed by a motor member ( 23 ) of the linear type formed by two double-acting cylinders in opposition. 10 - Folding machine according to claim 1, 8 or 9,
characterized in that the chassis ( 20 ) is suspended from the frame by a second pivot axis ( 22 ) located below the first being more distant than the latter from the folding spouts, a motor member ( 24 ) of the jack type being interposed between the chassis and this second axis. 11 - Folding machine according to claim 10,
characterized in that the chassis ( 20 ) is articulated on at least one lever or lifter ( 27 ) mounted on the second pivot axis ( 22 ) and coupled to the jack ( 24 ).

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