Abstract:
A controller is provided for machining devices of the type having a workpiece support table with a plurality of vacuum support devices mounted thereon for heightwise movement between an active raised position and an inactive lowered position. The controller includes at least one hydropneumatic actuator operably connected with the vacuum support devices, and shifting the same between the raised and lowered positions. A synchronization bar has at least one lock member that selectively engages and displaces heightwise in unison and at the same time each of the vacuum support devices operated by the hydropneumatic actuator.

Description:
CLAIM TO PRIORITY 
       [0001]    Applicants hereby claim the priority benefits under the provisions of 35 U.S.C. §119, basing said claim of priority on Italian Patent Application BS2010A000145, filed Aug. 25, 2010. 
       BACKGROUND OF THE INVENTION 
       [0002]    1. Field of the Invention 
         [0003]    The present invention relates to forming machines, and in particular to machines for profiling, shaping, cutting, sectioning, etc., various materials in sheet form, such as marble, granite and the like. The invention pertains more specifically to a controller and related system for positioning supporting devices that retain a sheet, or a flat workpiece, on the work table of an associated operating machine. 
         [0004]    2. Prior Art 
         [0005]    In the pertinent field of art, machining operations to be carried out on workpieces made of various materials, such as sheets of marble, granite and the like, may be performed using an operating or forming machine having a table for supporting the initial workpiece, a bridge structure situated above the workpiece support table and at least one operating head or electric chuck with at least one tool mounted on the bridge structure and movable relative to the workpiece on said table. 
         [0006]    The workpiece to be machined may be arranged and retained directly on the workpiece support table, but most frequently, must be kept in a raised position above the table when it is cut, sectioned and/or machined peripherally. For this second arrangement, it is customary to use support devices which are mounted on the workpiece support table and used depending on the geometry and dimensions of the workpiece and/or the machining operations to be carried out on it, and which must therefore be repositioned whenever the shape of the workpiece to be machined varies. 
         [0007]    These support devices may be in the form of vacuum support devices or suckers, small tables or the like. For the sake of simplicity, but without this constituting a limitation to the scope of the invention, in the present description, reference will be made solely to support devices in the form of suckers. 
         [0008]    The workpiece support table may be provided with a grid of suction holes which can be connected selectively to a vacuum-generating apparatus, wherein the suckers are arranged on said table opposite the holes according to the specific needs of the particular application, so as to define the actual work surface for the workpiece. Alternatively, the suckers are arranged on the workpiece support table, and may themselves be connected individually to a vacuum-generating apparatus directly. 
         [0009]    In order to position the workpiece on the workpiece support table, and allow the required machining operations to be carried out repeatedly on various parts of the workpiece to be machined, the suckers are movable, i.e., each movable selectively between an active raised position where the workpiece is supported thereon, and an inactive, concealed, lowered position, so as to avoid interference with the machining operations to be performed, wherein said positions may be defined by fixed stops. 
         [0010]    Such support suckers, which are movable and also directable, are generally known in the art. However, such support suckers, even though they may be arranged in the most suitable positions for the shape and size of the workpiece to be machined, when controlled according to the present state of the art technology, do not typically ensure a precise flatness and horizontal arrangement of the workpiece, so that the machining of every part thereof may be correctly and repeatedly performed. These suckers, in fact, may be operated only individually, with the problem being that it is not possible to ensure that all activated suckers will in each case assume the same height above the table, so that there may not be a properly flat support surface, thereby negatively affecting the stability and horizontal arrangement of the workpiece supported. 
       SUMMARY OF THE INVENTION 
       [0011]    One object of the present invention is to solve effectively the above-mentioned problems, and provide a mechanism for accurate operation and synchronized heightwise movement of the support suckers activated in each case. 
         [0012]    This object, and the implicit advantages arising therefrom, are achieved by a machine controller and related operating system according to at least claim  1 , comprising a hydropneumatic actuator module for each sucker to be operated, and a synchronization bar that is able to engage with and displace heightwise, in unison and at the same time, all the suckers operated by the respective hydropneumatic actuators. 
         [0013]    Advantageously, therefore, the support suckers may each be chosen individually and selectively by the respective hydropneumatic actuator. Then, the suckers to be actually activated are displaced heightwise with the aid of a mechanical synchronization bar, so as to be kept level during movement and be able to ensure that the workpiece resting thereon is flat and horizontal. 
         [0014]    Moreover, the actuator modules for the suckers on the workpiece support table may be grouped together in an ordered manner in a set on a single stand, in combination with the mechanical synchronization device, and this set of modules may be arranged alongside the workpiece support table or also at a distance therefrom according to needs. 
         [0015]    The whole arrangement will be managed by an operating program preset on the basis of the number and location of the suckers on the workpiece support table and the shape and size of the workpieces to be machined, which may involve the use of a variable number of suckers. 
         [0016]    These and other advantages of the invention will be further understood and appreciated by those skilled in the art by reference to the following written specification, claims and appended drawings. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0017]    The invention will moreover be illustrated more clearly in the remainder of the present description provided with reference to the accompanying drawings, which are provided by way of a non-limiting example and in which: 
           [0018]      FIG. 1  shows in schematic form a plan view of a machine tool with some support suckers on the workpiece support table; 
           [0019]      FIG. 2  shows a diagram of a hydropneumatic actuator module for operating each individual support sucker; 
           [0020]      FIG. 3  shows an example of a set of hydropneumatic units for operating a corresponding number of suckers, together with a mechanism for synchronizing the heightwise movements thereof; 
           [0021]      FIG. 4  shows an example of a set of solenoid valves for managing the hydropneumatic cylinders and the synchronization mechanism shown in  FIG. 3 ; and 
           [0022]      FIG. 5  shows another example of a set of hydropneumatic units for operating a different number of suckers. 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0023]    For purposes of description herein, the terms “upper”, “lower”, “right”, “left”, “rear”, “front”, “vertical”, “horizontal” and derivatives thereof shall relate to the invention as oriented in  FIGS. 3 and 5 . However, it is to be understood that the invention may assume various alternative orientations and step sequences, except where expressly specified to the contrary. It is also to be understood that the specific devices and processes illustrated in the attached drawings, and described in the following specification, are simply exemplary embodiments of the inventive concepts defined in the appended claims. Hence, specific dimensions and other physical characteristics relating to the embodiments disclosed herein are not to be considered as limiting, unless the claims expressly state otherwise. 
         [0024]    The drawings, in particular  FIG. 1 , show a machining apparatus or operating machine for machining materials, such as sheets of marble, granite or the like, denoted overall by  10 , having a workpiece support table  11  with a bridge crosspiece or beam  12  disposed above workpiece support table  11 , which carries at least one operating head  13  or electric chuck. 
         [0025]    The workpiece support table  11  is equipped with a support mechanism  15  which is arranged and used to define a support surface for the workpiece to be machined in a raised position above the table itself. The bridge beam  12  is movable on two shoulders  14  horizontally above the workpiece support table  11  along a first axis, while the operating head  13  is movable on and relative to the bridge beam  12  and the workpiece support table along at least two axes which are at right angles to each other, and perpendicular to the axis of movement of the bridge beam. 
         [0026]    In the example shown in  FIG. 2 , the support mechanism  15  is in the form of vacuum support devices or suckers  16 , which are located on the table  11  and can be selectively connected to the distributor portion of a vacuum-generating apparatus (not shown) by means of mobile pipes  15 ′. The number and arrangement of the support mechanism  15 , i.e., the suckers  16 , on the workpiece support table  11  may be chosen in each case depending on the shape and size of the workpiece and the machining operations to be performed on various parts of the workpiece. 
         [0027]    The suckers  16  may be used selectively, activating them so as to displace them heightwise above the workpiece support table  11  between a raised active position and a lowered inactive position, and then selectively applying a vacuum to the same. 
         [0028]    According to one feature of the invention, each sucker  16  is connected to a hydropneumatic actuator module  17 , and all the suckers  16  are associated with a synchronization bar  18 . 
         [0029]    In particular, for its displacements heightwise, each sucker is constrained to and movable with the stem  19  of a vertical-axis piston  20  operating inside a first hydraulic cylinder  21  mounted on the workpiece support table  11 . 
         [0030]    The hydropneumatic actuator module  17  associated with each sucker  16  is arranged in a set, together with the actuators  17  of the other suckers  16 , outside of the workpiece support table  11 , on one side thereof, and underneath or at a distance therefrom. The hydropneumatic actuator modules  17  will therefore be at least of a number equal to the number of suckers  16  on the workpiece support table  11  shown in  FIG. 1 , and grouped together in a set on a common stand  22 . Thus, for example, sets of eight actuator modules  17  may be provided, as shown in  FIGS. 1 and 3 , twenty four actuator modules  17 , as shown in  FIG. 5 , or any other number depending on the number of suckers  16  available and/or to be used on the same workpiece support table  11 . 
         [0031]    In greater detail, moreover, each illustrated hydropneumatic actuator module  17  comprises a second cylinder  23 , inside which a piston  24  is provided with a stem  25  that emerges or extends outwardly from one end of the cylinder  23 . The piston  24  defines on two opposite sides thereof inside the cylinder  23  of the actuator module  17 , a first chamber  26  intended to receive a gas or an aeriform fluid, typically pressurized air, and a second chamber  27  intended to receive a liquid fluid, such as a hydraulic oil. 
         [0032]    The first chamber  26  of the cylinder  23  of the actuator module  17  is supplied with and discharges therefrom pressurized air via a solenoid control valve  28 , which is located on a control panel  29 , through a respective so-called “up” connection line  30 . The second chamber  27  of the same cylinder  23  containing hydraulic fluid is in fluid communication, via a two-way connection pipe  31 , with the hydraulic first cylinder  21 , which operates the sucker  16 , on one side of the respective piston  20 . On the other side of the piston  20 , the first cylinder  21 , which operates the sucker  16 , has an outlet port connected to the above-mentioned solenoid control valve  28  via a so-called “down” connection line  32 . 
         [0033]    The hydropneumatic actuator module  17  may be designed as per the diagram shown, for example, in  FIG. 2 . In the embodiment shown in  FIG. 2 , the delivery of air to the first chamber  26  of the second cylinder  23  of the actuator module  17  is via the line  30 , and contemporaneously causes the discharging of air from the sucker support first cylinder  21  towards the solenoid valve  28 , which in turn produces a corresponding flow of hydraulic fluid from the second cylinder  23  of said actuator module  17  to the first cylinder  21  supporting the sucker  16 , so as to activate the latter, displacing it from a lowered position into a raised position. 
         [0034]    Vice versa, the delivery of air, via the line  32 , into the first cylinder  21  supporting the sucker  16 , together with the discharging of air from the first chamber  26  of the second cylinder  23  of the actuator module  17  towards the solenoid valve  28 , produces a corresponding return of the hydraulic fluid from the first cylinder  21  supporting the sucker  16  into the second chamber  27  of the second cylinder  23  of the actuator module  17 , so as to deactivate the sucker  16  by displacement from the raised position to the lowered, concealed position. 
         [0035]    According to another aspect of the present invention, synchronization of the movement of each of the suckers  16  to be activated for a particular application is performed mechanically by the synchronization bar  18 . For this purpose, and as shown in the example illustrated in  FIG. 3 , the stem  25  of each second cylinder  23  of the actuator module  17  extends inside and through a hole  18 ′ formed in the synchronization bar  18 , and is selectively locked to the bar  18  by a stem locking device  33 . The stem locking device  33  is normally kept in an unlocked position by means of an associated cylinder supplied with a fluid, preferably compressed air, delivered via a solenoid control valve  35  ( FIG. 2 ), so as to allow free sliding of the stem  25  with respect to the synchronization bar  18 . The stem locking device  33  is kept in the locked operating position by means of at least one spring  34 . 
         [0036]    The synchronization bar  18  is guided on and displaceable or shiftable along the stand  22  retaining the set of actuator modules  17 , in a direction generally parallel to itself, by means of a movement system preferably of the mechanical type, which comprises in the illustrated example, at least one toothed pinion  36 , which is driven and is movable along a mating toothed rack  37 , which extends generally parallel to the stems  25  of the set of actuator modules  17 , or by some other rigid guide system. 
         [0037]    Therefore, by means of the synchronization bar  18 , it is possible to operate simultaneously and in parallel all the suckers  16  which must be raised and activated for a particular application in order to support a workpiece, leaving the other suckers  16  lowered and inoperative. In order to activate the suckers  16 , it is sufficient to lock their stems  25  to the synchronization bar  18  by the respective stem locking device  33  and supply pressurized air to the first chambers  26  of the second cylinders  23  of the actuator modules  17 , which are operably connected so as to cause the delivery of hydraulic fluid from the second chambers  27  of said second cylinders  23  to the first cylinders operating the suckers  16  to be raised. The synchronization bar  18  will allow precise raising of all the suckers  16  thus operated, by the same amount, so as to define a resting surface having a flat and horizontal support for the workpiece which rests thereon in order to perform machining thereof. 
         [0038]    It should be noted moreover that the apparatus and system described above may be subject to variations or modifications without departing from the scope of the invention. 
         [0039]    In the foregoing description, it will be readily appreciated by those skilled in the art that modifications may be made to the invention without departing from the concepts disclosed herein. Such modifications are to be considered as included in the following claims, unless these claims by their language expressly state otherwise.