PANEL BENDING MACHINE WITH IMPROVED BLOCKING/RELEASE

MEANS

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

[0002] In particular, panel-bending machine tools, hereinafter panel-bending machines, are suitable for performing 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 sheet-pressing device and the blade-holder device are connected and supported by relative support arras which enable its movement during the processing phases of the sheets.

[0008] Panel-bending machines require elevated forces to bend the sheets and the tools and relative support arms are therefore subjected to elevated processing forces.

[0009] The tools and/or the relative support arms therefore tend to flex thereby risking jeopardising processing precision.

[0010] In addition, the tools tend to become worn with use and thereby require periodic replacement.

[0011] Consequently, connection mechanisms between the tools and the relative support arms are known of in the prior art which permit a rigid and robust support of the tools as well as the possibility of detachment and relative replacement when the wear limits provided for are reached.

[0012] The mechanisms of the prior art however have some technical disadvantages.

[0013] In fact, to achieve elevated processing precision, the clearance of such support mechanisms of the tool must be extremely limited: consequently the known mechanisms are very robust but also heavy and expensive to produce.

[0014] The need is therefore felt in the art to ensure functioning precision of the tools but also a reduction in their weight and dimensions and functioning and maintenance costs.

[0015] The purpose of the present invention is to make a panel-bending machine which overcomes the drawbacks mentioned with reference to the prior art.

[0016] Such drawbacks and limitations are resolved by a panel-bending machine according to claim 1.

[0017] Other embodiments of the panel-bending machine according to the invention are described in the subsequent claims.

[0018] 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:

[0019] figure 1 shows a perspective view of a panel- bending machine according to one embodiment of the present invention;

[0020] figures 2-8 show side views of the detail II in figure 1, in different functioning phases of the panel- bending machine in figure 1, as described further below .

[0021] The elements or parts of elements common to the embodiments described below will be indicated using the same reference numerals. [0022] 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.

[0023] Such applications should be considered merely as examples and not as exhaustive.

[0024] 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.

[0025] The panel-bending machine 4 comprises a support plane 8 able to support a sheet 12 during the various processing phases.

[0026] 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.

[0027] The panel-bending machine 4 further comprises an upright structure 24 which extends perpendicular to the support plane 8, in a vertical direction Y-Y, so as to tower over said support plane at least partially overhanging it.

[0028] The , panel-bending machine 4 further comprises at least one tool suitable to perform blocking and/or processing of the sheet 12 and at least one tool-holder head 32 which supports and/or moves said tool 28; the tool 28 being mounted in a detachable manner to the tool-holder head 32, by the interposition of blocking/release means 36.

[0029] In the appended drawings, the tool-holder head 32 is a sheet-blocking device suitable to block the sheet 12 in relation to said support plane 8 during the processing phases of said sheet 12; moreover the tool 28 is a sheet-presser tool which presses and compresses the sheet 12 against the support plane 8 so as to block it firmly to it.

[0030] The sheet-presser 28 may in general be a shaping tool, suitable for performing specific deformations on the sheet 12.

[0031] For the purposes of the present invention the tool- holder head 32 may also be a blade-holder device 40 fitted with blades 44 suitable for performing bending operations of said sheet 12, and said tool 28 may be, as said, a sheet bending blade 44.

[0032] The tool 28 is mobile in a vertical direction Y-Y and at least one horizontal direction X-X, perpendicular to said vertical direction Y-Y and substantially parallel to said support plane 8.

[0033] Advantageously, the tool-holder head 32 and the tool 28, at a reciprocal coupling interface 48, have attachment portions 52 counter-shaped to each other, which are shaped so as to form a horizontal abutment 56 and an undercut 60 in a vertical direction Y-Y.

[0034] According to one embodiment, the blocking/release means 36 comprise a blocking head 64 which compresses the tool-holder head 32 and/or the tool 28 in a horizontal direction X-X, so as to ensure contact between the counter-shaped attachment portions 52. This way the movement of the tool 28 in a horizontal direction X-X is prevented by the horizontal abutment 56 and the movement of the tool 28 in a vertical direction Y-Y is prevented by said vertical undercut 60.

[0035] According to one advantageous embodiment, the counter-shaped attachment portions 52 comprise an inclined plane 68.

[0036] The blocking head 64 comprises a thrust wall 72 which stops in abutment against the tool-holder head 32 and which presses the counter-shaped attachment portions 52 to touch each other.

[0037] Preferably, between the thrust wall 72 and the tool 28 there is a seat 76 which a stop plate 80 is inserted in, which is compressed, in a horizontal direction X-X between the thrust wall 72 and the tool 28 so as to ensure forced contact between the counter- shaped attachment portions 52.

[0038] The seat 76 for the stop plate 80 is of a sufficient thickness in a horizontal direction X-X to enable, following removal of the stop plate 80, the movement of the tool 28 in a horizontal direction X-X sufficient to disconnect the counter-shaped attachment portions 52 from each other to permit the complete removal of the tool 28 from the tool-holder head 32.

[0039] Preferably, the blocking head 64 is constrained to the tool-holder head 32 by means of threaded connection means 84 and the machine 4 comprises drive means 88 suitable to elastically deform the threaded connection means 84 so as to permit the extraction of the stop plate 80 in a vertical direction Y-Y, maintaining the mechanical connection between the blocking head 64 and the tool-holder head 32.

[0040] The drive means 88 comprise a hydraulic circuit which exerts a thrust effect in a horizontal direction X-X so as to horizontally deform the threaded connection means 84 to permit the horizontal translation of the blocking head 64 from the tool-holder head 32 and the extraction of the stop plate 80 in a vertical direction Y-Y.

[0041] According to one embodiment, the hydraulic circuit comprises an expansion chamber 92 made on the thrust wall 72 near the threaded connection means 84.

[0042] For example, the threaded connection means 84 comprise at least one screw or bolt having an attachment axis X'-X' and at least one attachment hinge 96 positioned on the thrust wall 72;

[0043] Preferably, the drive means 88 exert an axial thrust . on the blocking head _. 64 from the side opposite the attachment hinge 96 in relation to the attachment axis X' -X' .

[0044] According to one embodiment, the blocking/release means 36 comprise a gripping arm ■ 100 fitted with a finger 104 suitable for gripping the stop plate 80 and moving it so as to permit its extraction.

[0045] For example, the finger 104 is inserted in a recess 106 made on the stop plate 80.

[0046] Preferably, the gripping arm 100 comprises a support bracket 108 which identifies, together with the finger 104, a cavity 112 counter-shaped to a gripping appendage 116 made on the tool 28, so as to release the stop plate 80 and remove the tool 28 automatically, gripping the latter by said gripping appendage 116. [0047] In particular, the gripping appendage 116 is shaped so as to form an undercut in a horizontal direction X-X so as to permit its gripping and horizontal extraction from the gripping arm 100.

[0048] The functioning of the panel-bending machine according to the present invention will now be described .

[0049] In particular, in figure 2 the tool 28 is blocked: in fact the threaded connection means 84 press the stop plate 80 against the tool 28 so as to lock the attachment portions 52 to each other.

[0050] The inclined plane 68 constrains the movements and vertical and horizontal clearances between the tool- holder head 32 and the tool 28 to each other. In this step, the drive means 88 are deactivated and stop plate 80 is blocked in a state of compression.

[0051] To release the tool 28, the drive means 88 are activated: for example the hydraulic 'pressure exerted on the thrust wall 72 determines first of all the elastic elongation of the threaded connection means 84.

[0052] Preferably, at the interface between the blocking head 64 and the tool-holder head 32 the threaded connection means 84 have a smooth stem 118 to permit the free sliding of the blocking head 64: in other words, the engagement threads 120 are positioned inside the tool-holder head .32 on the side opposite the blocking head 64.

[0053] Preferably, under the axial elongation of the threaded connection means 84, the blocking head 64 rotates in relation to its attachment hinge 96, thanks to the fact that the thrust of the drive means 88 is applied from the side opposite the hinge in relation to the attachment axis X'-X'.

[0054] This way, the stop plate 80 is liberated of the compression and can be removed (figure 3) .

[0055] The gripping arm 100 approaches the tool so as to engage the finger 104 in the recess 106 (figure 4); the stop plate 80 is then extracted in a vertical direction Y-Y, thanks to the movement of the finger 104 (figure 5) .

[0056] Thanks to the vertical closure of the finger 104 towards the support bracket 108, the gripping appendage 116 is blocked inside the cavity 112 and is ready to be extracted horizontally (figure 5) .

[0057] The tool 28 is then extracted in a horizontal direction X-X (figure 6) and vertical direction Y-Y (figure 7) so as to completely release the attachment portions 52 from each other. Lastly, the tool is removed completely (figure 8) .

[0058] Obviously, following the removal of the tool 28, a subsequent tool 28 may be fitted repeating the same steps in the reverse order. In particular, the tool 28 is positioned next to the tool-holder head 32 by the gripping arm 100 and the drive means 88 are activated to again create a seat of sufficient width to accommodate the stop plate. The elasticity of the threaded connection means 84 makes it possible to achieve a deformation sufficient for such insertion /removal of the stop plate 80 each time without ever having to remove said threaded connection means 84.

[0059] Lastly, the tool 28 is inserted realising the shaped coupling between the attachment portions 52 and the drive means are released, that is deactivated, so as to ensure the slotting of the stop plate 80 in its seat 76: such slotting guarantees the continuous contact between the attachment portions 52.

[0060] 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.

[0061] In particular, the improved blocking/release means of the tools permits elevated processing precision in that it keeps . the coupling clearances within an extremely limited range. In fact, the presence of an inclined plane constrains the vertical and horizontal clearances to each other, enabling the machine to keep recovery of such clearances under control.

[0062] Moreover, the blocking means as a whole proves lightweight and inexpensive to produce.

[0063] Moreover, the blocking means proves lightweight and of reduced dimensions compared to the device of the prior art.

[0064] Moreover, the release, replacement and subsequent blocking of the tools replaced is fully automated and fast to perform.

[0065] This way machine downtime is considerably limited and the overall efficiency of the machine tool is increased.

[0066] On the whole, the panel bending machine according to the present invention has reduced dimensions, weight and costs compared to the panel-bending machines of the prior art, while maintaining highly precise processing.

[0067] 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.