"PANEL BENDING MACHINE TOOL WITH IMPROVED MOVEMENT OF THE

BLADE -HOLDER DEVICE"

[0001] The present invention relates to a panel bending machine tool, suitable to perform mechanical bending of metal sheets.

[0002] I n particular, panel-bending machine tools, hereinafter panel-bending machines, are suitable to perform bending operations of metal sheets, having elevated axial extensions and reduced thicknesses.

[0003] Such panel-bending machines usually comprise a bench structure having a horizontal support shelf to support the sheet to be processed.

[0004] The sheet which a sheet-pressing device and blade- holder device act on is laid on said support shelf.

[0005] The sheet-pressing device is used to block the sheet firmly to the support shelf to prevent unwanted deformation of the same during the relative stages of bending .

[0006] The blade-holder device supports the blades, or in general tools of various forms, depending on the mechanical processing to be performed on said sheet, which are pressed against the sheet after this has been firmly blocked to the support plane.

[0007] The movement of the sheet-pressing and blade-holder devices must be synchronised so as to achieve accurate, fast and efficient processing.

[0008] In addition, the need is also felt to reduce the production costs of the panel-bending machine.

[0009] In the prior art, to ensure the movement of the blade-holder devices, multiple mechanisms are required which make the panel-bending machine cumbersome and complicated .

[0010] In particular, the blade-holder devices are provided with a vertical movement, that is perpendicular to the blade fixed to the support plane, and a horizontal movement, that is parallel to the sheet itself.

[0011] The vertical movement is connected to the deformation of the sheet: in other words, the blade or tools of the blade-holder device move perpendicular to the sheet and deform it by bending.

[0012] The horizontal movement of the blade-holder device is required, rather, to accompany the bending without rubbing, but also to allow the exit or extraction of the blades from the sheet following each bending operation, especially when performing ^Λ υ' or ^Λ 0' bendings which create undercuts.

[0013] To ensure good machine precision, and thereby low processing tolerances, it is important to disengage the horizontal movement and the vertical movement from each other .

[0014] To such purpose the blade-holder device is usually mounted on a first carriage in turn connected to vertical drive means, such as a piston, which impresses on the carriage, and thereby on the blade-holder, a purely vertical movement. The connection between the first carriage and the drive means envisages for example a horizontal sliding block which thus ensures the joint translation of the blade-holder with the drive means in a vertical direction while permitting an independent horizontal relative movement of the carriage, and thereby of the blade-holder, in relation to the vertical drive means .

[0015] This way it is possible, regardless of the vertical position of the blade-holder device, to impress a horizontal movement on the latter, by means of the horizontal drive means.

[0016] Two solutions of this type are known of in the art. In a first solution, an inclined plane is positioned between the horizontal drive means and the blade-holder device. The inclined plane makes it possible to disengage the horizontal movement from the vertical movement of the blade-holder but has the disadvantage of being extremely expensive to make. In fact, to make sure that no sticking of the blade-holder occurs, the inclined plane needs to be made with very strict and therefore very expensive processing tolerances.

[0017] It is also known of to use a connection and horizontal movement arm of the blade-holder which performs the horizontal movement of the blade-holder: such arm is hinged to a support structure and, rotating, moves the blade-holder horizontally.

[0018] Such solution is cheaper than that envisaging the connection to an inclined plane but does not guarantee adequate disengagement of the horizontal and vertical movements. Consequently, such oscillating arm solution is not very precise.

[0019] It follow that the solutions of the prior art are unable to guarantee accurate processing and reduced production costs.

[0020] The purpose of the present invention is to make a panel-bending machine which overcomes the drawbacks mentioned with reference to the prior art.

[0021] Such drawbacks and limitations are resolved by a panel-bending machine according to claim 1.

[0022] Other embodiments of the panel-bending machine tool according to the invention are described in the subsequent claims.

[0023] Further characteristics and advantages of the present invention will be more clearly comprehensible from the description given below of its preferred and non-limiting embodiments, wherein:

[0024] figure 1 shows a perspective view of a panel-bending machine according to one embodiment of the present invention;

[0025] figure 2 shows a perspective view, from a different angle, of the panel-bending machine in figure 1 ;

[0026] figure 3 shows a side view of the panel-bending machine in figure 1, in a first operative condition of functioning in which the blade-holder device is in a rearward position;

[0027] figure 4 shows a side view of the panel-bending machine in figure 1, in a second operative condition of functioning in which the blade-holder device is in a forward position;

[0028] figures 5-6 show enlarged views of a detail of the panel-bending machine in figure 1, in different functioning configurations, as described further below.

[0029] The elements or parts of elements common to the embodiments described below will be indicated using the same reference numerals.

[0030]With reference to the aforementioned figures, reference numeral 4 globally denotes a panel-bending machine tool, hereinafter panel-bending machine, suitable to perform bending of sheets, such as metal sheets using in the furnishing and household appliances sectors, and the like.

[0031] Such applications should be considered merely as examples and not as exhaustive.

[0032] In other words, the panel-bending machine according to the present invention may also be used to bend non- metal sheets; moreover the concept of sheet should be understood broadly, including for example elements having quite a squat shape, that is to say sheets of elevated thickness.

[0033] The panel-bending machine 4 comprises a support plane 8 able to support a sheet 12 during the various processing phases. The support plane 8 is substantially horizontal, parallel to a base of the machine itself.

[0034] Preferably, the support plane 8 comprises a plurality of support beams 16 positioned alongside each other so as to form gaps 20 so as to permit the support of the sheet at least partially overhanging said gaps 20.

[0035] The panel-bending machine 4 further comprises an upright structure 24 which extends perpendicular to said support plane 8 so as to tower over said support plane at least partially overhanging it.

[0036] The panel-bending machine 4 comprises at least one sheet-blocking device 28 able to constrain the sheet 12 in relation to said support plane 8 during the processing phases of the sheet 12 and at least one blade-holder device 32 fitted with blades 36 suitable to perform bending operations of said sheet 12.

[0037] Preferably, the sheet-blocking device 28 and/or the blade-holder device 32 are mechanically constrained to the upright structure 24.

[0038] Advantageously, the panel-bending machine 4 comprises vertical drive means 40 operatively connected to the sheet-blocking device 28 and to the blade-holder device 32.

[0039] According to one possible embodiment, said vertical drive means 40 comprise a device body 42, fixed in relation to the upright structure 24, pistons, not shown, mobile in relation to the device body 42 and to the upright structure 24 being operatively connected to such device body 42.

[0040] In particular, said vertical drive means 40 move both the sheet-blocking device 28 and the blade-holder device 32 in a vertical direction Z-Z, substantially perpendicular to said support plane 8.

[0041] Such vertical movement occurs in the two opposite directions (shown in the drawings by the arrows ^Λ Ό' and ^Λ υ' ) , that is to say respectively towards and away from a base of the panel-bending machine.

[0042] According to one embodiment, the sheet-blocking device 28 comprises a blocking portion 48 of the sheet 12 mechanically connected to the drive means 40 by means of a connection arm 50.

[0043] For example, the blocking portion 48 comprises at least one jaw 52 able to press at least a portion of the sheet 12 to be processed against a corresponding abutment 56 of the support plane 8.

[0044] Said abutment 56 may be of the fixed or mobile type.

[0045] Preferably, the sheet-blocking device 28 is of the sheet-pressing type: in other words, the blocking portion 48 comprises a jaw 52 which presses and compresses the sheet 12 against the support plane 8 so as to block it firmly to it.

[0046] Preferably, the abutment 56 is situated near a lateral rim 60 of the support plane 8 so as to permit easy bending of the sheet 12 in correspondence with a portion of the same overhanging said lateral rim 60.

[0047] According to one embodiment, the sheet-blocking device 28 comprises a plurality of shaping tools, able to perform deformations on the sheet 12.

[0048] The blade-holder device 32 preferably comprises a fastening portion 64 operatively connected to the vertical drive means 40.

[0049] According to one embodiment, the blade-holder device 32 comprises a blade-holder head 68 mechanically connected to the vertical drive means 40 by means of at least one transversal skate 72 which forms a mobile coupling in a transversal direction Y-Y, perpendicular to said vertical direction Z-Z and substantially parallel to the support plane 8.

[0050] Preferably, the transversal skate 72 is inserted between the blade-holder head 68 and the fastening portion 64.

[0051] The coupling made by the transversal skate 72 is a prismatic type coupling which allows a relative translation of the blade-holder head 68 and the fastening portion 64 in a transversal direction Y-Y and prevents a relative movement between the blade-holder head 68 and the fastening portion 64 in a direction perpendicular to said transversal direction Y-Y, and in particular in a vertical direction Z-Z.

[0052] The blade-holder head 68 comprises at least one blade 36 suitable to perform bending operations of said sheet 12.

[0053] Preferably, the blade-holder head 68 comprises a pair of blades 36 opposite each other, for example in a vertical direction Z-Z, so as to perform opposite bending movements of the sheet 12 depending on the direction of operation ^Λ υ' or ^Λ Ρ' of the blade- holder head 68.

[0054] Advantageously, the panel-bending machine 4 comprises transversal movement devices 80 suitable to move the blade-holder device 32 in a transversal direction Y-Y.

[0055] The transversal movement devices 80 are mechanically separate from the vertical drive means 40: this way it is possible to confer to the blade-holder head 80 totally disengaged and independent vertical and transversal movements .

[0056] According to one embodiment, the transversal movement devices 80 comprise a pusher 84 operatively connected to the blade-holder head 68 by means of a jointed parallelogram kinematism 88 comprising a drive plate 92, at least one guide plate 96 and at least two hinge rods 100.

[0057] In particular, the drive plate 92 is connected to the pusher 84 from which it receives the drive movement, the guide plate 96 is connected to the blade-holder head 68 which translates in a transversal direction Y-Y.

[0058] The guide plate 96 is bound to the hinge rods 100 by respective eccentric shafts 104, so as to present a misalignment 108 between axes of symmetry S of the shafts 104 and the hinge points 112 of the eccentric shafts 104 and the drive plate 96.

[0059] At least at respective fastening portions with said drive 92 and guide plates 96, said eccentric shafts 104 have a circular cross section so as to enable reciprocal rotation of the parts.

[0060] The hinge rods 100 are each hinged to the drive plate 92 and the guide plate 96 and are the same length, so as to always rotate parallel to each other and to also ensure the reciprocal parallelism of said drive 92 and guide plates 96.

[0061] The guide plate 96 is in turn constrained to the blade-holder head 68 by a vertical sliding block 116 which forms a prismatic coupling between the guide plate 96 and the blade-holder head 68: such prismatic coupling permits solely reciprocal vertical movements between the guide plate 96 and the blade-holder head 68.

[0062] It follows that when the pusher 84 is in the retracted position (figure 3) the drive plate 92 rises in the direction ^Λ υ' and drags towards it the guide plate 96 which moves the blade-holder head 68 away from the sheet 1, in a transversal direction Y-Y.

[0063] The blade-holder head 68 cannot move vertically inasmuch as constrained by the vertical drive means 40 but can translate in a transversal direction Y-Y in relation to these by means of the interposition of the transversal skate 72. In the transversal rearward movement the guide plate 96 translates vertically to the blade holder head 68 by means of the vertical sliding block 116.

[0064] When the pusher 84 is moved to the extracted position (figure 4) the drive plate 92 lowers and distances from itself the guide plate 96 which moves the blade-holder head 68 towards the sheet 1, in a transversal direction Y-Y. The blade-holder head 68 cannot move vertically inasmuch as constrained by the vertical drive means 40 but can translate in a transversal direction to these by means of the interposition of the transversal skate 72. In the transversal forward movement the guide plate 96 translates vertically to the blade holder head 68 by means of the vertical sliding block 116.

[0065] It is to be noted that the entity of the transversal shift of the blade-holder head 68 is given at maximum by double the eccentricity or misalignment 108 of the eccentric shafts 104 and the hinging points 112 of the guide plate 96.

[0066] Preferably, the jointed parallelogram kinematism 88 comprises a drive plate 92 in positioned in a median position and connected to the pusher 84, two hinge rods 100 connected to it, and two eccentric shafts 104 which extend from opposite sides of the drive plate 92 in a longitudinal direction X-X, perpendicular to said vertical Z-Z and transversal Y-Y directions. [0067] At opposite longitudinal ends 120 of the eccentric shafts 104, the jointed parallelogram kinematism 88 comprises two respective guide plates 96 mounted eccentrically in relation to said eccentric shafts 104 with equal misalignment 108. Each of said guide plates 96 mounted on opposite longitudinal ends 120 is connected to separate longitudinal portions of the blade-holder head 68 so as to firmly guide the transversal movement of the latter .

[0068] The guide plates 96 are in turn connected to the blade-holder head 68 by means of respective vertical sliding blocks 116.

[0069] As may be seen from the description, the panel- bending machine according to the invention makes it possible to overcome the drawbacks mentioned with reference to the prior art.

[0070] In particular, the use of a jointed parallelogram kinematism makes it possible to totally disengage the transversal and vertical movements of the blade-holder head ensuring both high production tolerances and reduced production costs.

[0071] In fact, the kinematism guarantees constant parallelism of the guide plates and drive plates and thereby impresses purely transversal movement on the blade-holder head, while the vertical drive means shift the blade-holder head in a purely vertical direction in a totally independent manner.

[0072] Moreover, the production costs of the jointed parallelogram kinematism are certainly lower than those of the prior art related to the use of inclined planes which require strict processing tolerances.

[0073] On the whole, the panel bending machine according to the present invention has improved precision and reduced costs compared to the panel-bending machines of the prior art .

[0074] A person skilled in the art may make numerous modifications and variations to the panel-bending machines described above so as to satisfy contingent and specific requirements, while remaining within the sphere of protection of the invention as defined by the following claims.