Abstract:
This invention refers to a woodworking machine equipped with fastening devices capable of allowing the processing of items of complex shape and variable size, characterized in that it provides a multiple number of devices which are mobile and capable of being positioned on a working plane independently from each other, where each of said devices simultaneously constitutes both a striking element for positioning the item and a blocking element for the same.

Description:
FIELD OF THE INVENTION 
     This invention offers a woodworking tooling machine capable of processing items of variable size and complex shape, as well as the relative new method. The machine according to the invention comprises a multiple number of item blocking devices, capable of also acting as stops for the same, where each of said units is mobile and capable of being positioned at will along the working plane. 
     The method according to the invention provides for positioning a first series of said units, arranging the item to be processed against said stops, blocking it at one or more sides and performing the processing on the free sides, then moving additional devices to block the item at the processed sides, removing the initial blocking devices, and completing the processing on the remaining side. This system allows the machine to be quickly and easily adapted to the processing of items of any shape, thus achieving an extremely flexible machine, capable of drastically reducing the dead moments needed on the known machines for preparing them to process new items. 
     BACKGROUND OF THE INVENTION 
     It is known that a correct positioning of the item to be processed is of fundamental importance in the processing done by tooling machines. 
     Various systems for positioning and blocking an item are known, system which vary depending on the type of processing to be performed. 
     U.S. Pat. No. 5,700,117 by the same applicant described a tooling machine for the processing of panels where the working plane comprises a pair of guides arranged along a first axis, on which a multiple number of guides are sliding and each carrying one or more mobile fastening devices mounted on the cross beam along an axis set at an orthogonal direction with respect to that of the previous axis. 
     As mentioned above in these known machines the items is fastened by placing the item on suction-cup elements connected to aspirating devices capable of creating a vacuum inside the suction cup, so as to block the panel during the processing step. This system, while suitable for panels, presents however a few limitations whenever the processing is to be done on items of limited width and of complex shape, which need to be processed on all sides and which are difficult to position and block on the working plane. 
     The limitations of the known machines are in particular evidence whenever the type of processing needs to be frequently changed, because of the dead moments needed for preparing the working plane and the relative stops, whenever the item to be processed is to be changed. 
     SUMMARY OF THE INVENTION 
     In order to overcome this problem this invention offers a woodworking tooling machine equipped with a working plane comprising a pair of guides arranged along a first axis, a series of mobile cross beams oriented along an axis orthogonal to the previous one, a multiple number of supports capable of sliding along said cross-beams, each carrying a pair of item striking and blocking devices, where each striking and blocking device comprises a pressing device and some suction devices controlled independently from each other. Each support of the blocking devices presents a seat capable of being engaged by an element mounted on the machine&#39;s operating head, which can thus be utilized for positioning the support on the working plane. 
     According to an alternative version of the invertion, the working planes are two and the device for the positioning of the supports is capable of engaging said seats into the supports which are freely mobile along a first axis, while the working planes are mobile along an axis orthogonal to the previous one. 
     The combination of these two motions makes it possible to place the supports on a working plane, while the operating head performs the operation on the other plane. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     This invention will now be described in detail, for exemplifying and non limiting purposes, with reference to the attached figures in which: 
     FIG. 1 offers a simplified topside view of a working plane of a machine according to the invention, 
     FIG. 2 is a cross section of the item striking and blocking devices of the machine according to the invention, 
     FIG. 3 is a vertical cross section of the working plane fitted with the striking and blocking devices, 
     FIG. 4 is; a simplified view of the working planes with the item positioning devices in an alternative embodiment of the invention. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     With reference to FIG. 1, the number  1  indicates the working plane of a tooling machine, above which moves an operating head not shown in the figure as it is of a known type, equipped with one or more electrical spindles and set so as to be freely moving along a triplet of Cartesian axes in order to perform the various processing operations. 
     The working plane  1  comprises a pair of guides  2  arranged along an axis, for instance along the axis X, which mount a pair of fixed cross beams  3  and a series of mobile cross beams  4 , all oriented according-to an axis orthogonal to the previous one, in particular along the axis Y. The cross beams mount a multiple number of item striking and blocking devices, indicated in the overall by the number  5  and described in further detail in FIG.  2 . 
     The fixed cross beams  3  and the extremities of the mobile cross beams  4  also provide for a series of fixed striking elements  6 , to be used for positioning the items, whenever needed. 
     The striking and blocking devices described in detail in the FIGS. 2 and 3, each comprise a support  7  mounting a pressing element  8  which presents some suction cups in its upper part. 
     The number  10  indicates a par of grooves provided in the lateral walls of the cross beams. The support  7  mounts a mobile vertical plate  11 , which holds one or more screwed-on pairs of bolts  12 , whose heads  13  refer to the grooves  10 . 
     The thickness of the heads  13  is less than the depth of the grooves  10 , so that the plate  11  is capable of effecting some small motions upward and downward, equal to the difference between the depth of the grooves  10  and the thickness of the heads  13 . 
     The plate  11  is crossed by the rod of a piston  14 , which slides inside a chamber  15  provided in the support  7 . 
     The extremity of the rod  14  projects inside a seat  16 , which is limited by a cylindrical wall  17  firmly attached to the plate  11 . 
     Some devices of a known type, not shown in the figure, convey compressed air into the zone separating the support  7  and the plate  11 . 
     The air pressure will normally keep the plate  11  pushed upward, while the head  13  of the bolts are locked against the upper wall of the grooves and block the support  7  on the cross beam. 
     In order to shift the support, it suffices to insert a pin into the seat  16  soas to push the piston down and to discharge the compressed air across the chamber  15 , thus allowing the plate  11  to drop and unblock the support, which can thus freely slide along the cross beam. 
     The pin inserted into the seat  16  may for example be a pinmounted in the operating head of the machine, which may thus be used for properly positioning the fastening units on the working plane, or a pin mounted on a mobile support, as in a further preferred embodiment of the invention, which will be described later. 
     Each support  7  provides for two cylinders  18 , each fitted with a piston indicated by the number  19 , which slides along a central rod  20  inside the chamber  18 . 
     The piston  19  is firmly attached to a sleeve  21 , which also slides on the rod  20  and acts both as a striking element for positioning the item to be processed indicated by the number  22  on the working plane, as well as a support for the pressing element  8 , used for blocking the item  22 . 
     The cylinder  18  holding the sliding piston  19  is closed in its upper part by a wall or closing element  23 , which acts as a guide for the sleeve  21  and presents its central portion, indicated by the number  24 , projecting upward. 
     An annular element is provided above the wall  23  and around the projecting part  24 , which is mobile in an essentially vertical direction and kept pressed downward by a pair of springs  26  or the like. 
     A non-illustrated duct conveys compressed air into the cylinder  18  above the piston  19 , as well as into the annulus between the wall  23  and into the mobile annular element  25 . 
     The same compressed air therefore draws the piston  19  downward, and pushes the annular element  25  upward. 
     A duct  36  axially crossing the rod  20  exits in its upper part opposite an opening provided in the pressing element  8 , which is closed by a valve  27 . 
     FIG. 4 offers a simplified view of another preferred embodiment of the invention, which provides for two working planes, indicated by the numbers  40  and  41 , respectively. 
     Even in this case, each working plane includes the guides  2  with their cross beams  3  and  4 , equipped with striking and blocking units  5 . 
     Contrary to the previous embodiment, however, the motion of these units is induced, in addition to the pin mounted on the operating head and designed to fit into the seat  16  provided in the plate  11  of the support  7 , by a separate device which comprises a guide  42  set parallel to one of the machine axes, for example parallel to the axis X, on which a support  43  moves, while mounting a piston actuating a pin or the like, to move in an essentially vertical direction, so as to insert itself into the seats  16  and cause the shifting of the blocking and fastening units. 
     In this case the motions along the axis X may be achieved by controlling the shift of the unit  43  along its guide  42 , while the shifts in the direction of the axis Y may be achieved by controlling the motions of the working planes  40  and  41 , respectively. 
     This configuration allows totally eliminating any dead periods, because as the operating heads performs the operations on a working plane, it is simultaneously possible to position a subsequent item on the other plane, by using the device  43  which takes care of properly positioning the various striking and blocking units. 
     Before the start of processing, it is moreover possible to simultaneously position the supports on both planes, by using the operating head for one of them, and the device  43  for the other. As will be clear from the above description, the method according to the invention then provides for the following phases: 
     positioning of one or more items against striking and blocking units on the working plane, 
     positioning of the items against said striking and blocking units effected by the same, 
     performing the expected processing work on the free edges of the items, 
     positioning of further striking and blocking units against the edges of the item already processed, and blocking of the same, 
     unblocking and removal of the first positioning and blocking units, 
     completing the processing on the remaining edge of the item. 
     This has allowed achieving a tooling machine of an extreme flexibility, capable of processing items of various sizes and of complex shapes, while easily and rapidly adapting to the shape of the items, without any need for complex preparing operations, which would involve numerous dead time periods. 
     An expert of the trade may then provide various modifications and variants, all of which can however be deemed to fall within the scope of this invention.