Patent Publication Number: US-2009235514-A1

Title: Machine for assembling metal section bars of frames

Description:
The invention relates to a machine tool arranged for assembling metal section bars of casings. 
     In particular, the invention relates to a caulking machine arranged for caulking metal section bars for making casings of frames, such as, for example, windows, french windows, doors, shutters, and the like. 
     The caulking machines used in the door and window industry, or corner assembling machines, are arranged for fixing the corners of the casings. 
     Each corner of a casing is defined by a pair of metal section bars, for example extruded aluminium sections, that are appropriately placed near one another and previously connected at respective end portions by connecting elements, or corner joints. 
     Each corner joint, which for example also may be an extruded aluminium section, comprises a pair of arms each provided with a fixing seat, and arranged in such a way as to make a substantially L-shaped structure. 
     Each arm is arranged for being inserted into a respective housing obtained in the aforesaid end portions of the section bars to be joined. 
     In order to fix a pair of section bars to the respective corner joint, and thus make a corner of the casing, it is necessary to deform plastically a portion of the metal section bars that is positioned near the corresponding fixing seat. 
     In this way, the deformed portions each engage the respective fixing seat, achieving mechanical locking between the section bars and the corner joint interposed therebetween. 
     Subsequently, depending on the different types of casings that it is desired to make, a glue can be injected into holes that have previously been made in the section bars, which glue is arranged for stably fixing the section bars. 
     Caulking machines are known that are arranged for fixing the corners of a casing, comprising a box framework closed below by a base and by a supporting plate above. 
     With the supporting plate there is associated a supporting element, which is substantially L-shaped, arranged for supporting, in use, a pair of section bars to be caulked, previously connected by a corner joint by an operator. 
     These machines further comprise a caulking head supported by the supporting plate and arranged for caulking and gluing, each time, a pair of section bars, until the desired casing is made. 
     In particular, the caulking head is provided with a caulking clamp, positioned near the vertex of the supporting element, comprising a pair of jaws, each supporting a metal cutter arranged for plastically deforming a respective portion of metal section bar facing the latter. 
     In order to make a casing using known caulking machines, it is therefore necessary for an operator to connect manually a first section bar to a second section bar by a first corner joint, position an L-shaped structure thus obtained on the supporting element, and manually drive the caulking head, which fixes the first section bar to the second section bar and makes a first corner of the casing. 
     Subsequently, the operator removes from the caulking machine the L-shaped structure that has just been fixed, inserts into one of the free ends of the latter a second corner joint, and associates therewith a third section bar, obtaining a U-shaped structure. 
     Subsequently, the operator manually positions the U-shaped structure thus obtained on the supporting element, and manually drives the caulking head that fixes the third section bar to the L-shaped structure, making a second corner of the casing. 
     Still subsequently, the operator removes from the caulking machine the thus fixed U-shaped structure, inserts a third and a fourth corner joint into a fourth section bar and associates the fourth section bar with the free ends of the U-shaped structure, obtaining a closed, for example rectangular, structure. 
     Subsequently, the operator manually positions the closed structure thereby obtained on the supporting element, and manually drives the caulking head that fixes the fourth section bar to one of the free ends of the U-shaped structure so as to make a third corner of the casing. 
     Still subsequently, the operator removes the partially fixed closed structure, rotates the partially fixed closed structure and repositions the partially fixed closed structure on the caulking head that fixes a fourth corner of the casing. 
     It should be noted that during caulking operations, the caulking forces are discharged by the caulking clamps onto the supporting plate, caulking clamps being associated with the latter by a threaded connection. 
     A drawback of known caulking machines consists of the low productivity thereof. 
     In fact, these machines enable only one corner at a time to be caulked, which corner must have been previously assembled manually by an operator. 
     A further drawback consists of the need to provide an operator, with a consequent increase in production costs, to perform manually the tasks of assembling and positioning on the caulking machine the section bars to be fixed. 
     This means that such tasks are excessively slow and laborious. 
     Further, the operator may commit centering errors and compromise the subsequent caulking of the section bars, or injure himself by coming into contact accidentally with the free ends of the section bars to be joined. 
     Also manually moving the partially assembled section bars, in particular for section bars of large dimensions, may be particularly heavy for the operator. 
     A still further drawback relates to the operations that are necessary for reconfiguring the aforesaid caulking machines following a change in the size of the section bars to be caulked. 
     In fact, these operations are particularly slow and difficult. 
     An object of the invention is to improve the machine tools arranged for assembling metal section bars of casings. 
     Another object is to improve machine tools arranged for caulking metal section bars for making casings. 
     A further object is to make machine tools that enable productivity to be increased with respect to known caulking machines. 
     A still further object is to obtain machine tools that enable the section bars to be assembled rapidly. 
     Still another object is to make machine tools that enable rapid and precise centering of the section bars to be assembled. 
     Another still further object is to make machine tools that are easily and rapidly reconfigurable following a change in the size of the section bars to be caulked. 
     Still another object is to obtain caulking machines provided with a device for discharging the caulking forces that is alternative to known devices. 
     In a first aspect of the invention, there is provided a machine tool for assembling metal section bars of casings comprising an assembly unit arranged for supporting and assembling said metal section bars and which is movable between a first operating position in which said metal section bars are positionable on said assembly unit and a second operating position in which said metal section bars can be subjected to a desired machining. 
     This machine tool may comprise at said first operating position and at the aforesaid second operating position respectively a first manipulating unit and a second manipulating unit, each of which is provided with an anthropomorphic robot. 
     In particular, the anthropomorphic robot of the first manipulating unit is arranged for loading said metal section bars on said assembly unit, whilst the anthropomorphic robot of the second manipulating unit can be provided with caulking means arranged for caulking and gluing said metal section bars, or with a drilling unit arranged for drilling said section bars, or with a broaching machine arranged for inserting broaches into said section bars, or with a screwing head. 
     Owing to this aspect of the invention, it is possible to make highly automated machines that enable the metal section bars to be positioned, assembled and caulked automatically. This enables the productivity of the machines to be significantly increased by reducing production time and reducing or even eliminating the need for an operator. 
     This further enables the machine to be reconfigured easily and quickly following a change in the size of the section bars to be assembled. 
     In fact, it is sufficient, depending on the size of the section bars to be assembled, on the one hand to reprogram appropriately the assembly unit, the first manipulating unit and the second manipulating unit and on the other to change, if necessary, the caulking tools. 
     In a second aspect of the invention, there is provided a machine tool arranged for assembling elongated elements for making casings, comprising supporting frame means arranged for supporting said elongated elements and centering means arranged for centering said elongated elements on said supporting frame means, characterised in that said centering means comprises compensating means arranged for compensating possible dimensional variations of said elongated elements. Owing to this aspect of the invention it is possible to obtain centering means that enables the section bars to be centred precisely on the supporting frame means. 
     In a third aspect of the invention, there is provided a machine tool arranged for caulking metal section bars for making casings, comprising supporting frame means and clamp means arranged respectively for supporting and for caulking said metal section bars, characterised in that said machine tool further comprises coupling means arranged for removably coupling said clamp means with said frame means. 
     In an embodiment of the invention, the coupling means comprises pin means associated with the clamp means, and seat means associated with the supporting frame means, the pin means being arranged for engaging said seat means in a removable manner. 
     Owing to this aspect of the invention, it is possible to make a device for discharging caulking forces that is an alternative to known devices. 
     In fact, the caulking forces are discharged by the pin means directly onto the supporting frame means. 
    
    
     
       The invention can be better understood and implemented with reference to the attached drawings in which an embodiment of the invention is shown by way of non-limiting example, in which: 
         FIG. 1  is a schematic top view of a system for machining and assembling casings of frames; 
         FIG. 2  is a schematic front view, with some details removed, of an assembly unit included in the system in  FIG. 1 ; 
         FIG. 3  is a top view of the assembly unit in  FIG. 2 ; 
         FIG. 4  is a schematic front view of a centering device included in the assembly unit in  FIG. 2 ; 
         FIGS. 5 to 10  illustrate a possible operating sequence of the system in  FIG. 1 ; 
         FIG. 11  is a top view of a caulking device included in the system in  FIG. 1 ; 
         FIG. 12  is a partially sectioned view from below of the caulking device in  FIG. 11 ; 
         FIG. 13  is a longitudinal section of the caulking device in  FIG. 11 . 
     
    
    
     With reference to  FIG. 1 , there is illustrated a system  1  used in the door and window industry for machining and assembling casings  2  of frames ( FIG. 10 ) such as, for example, windows, french windows, doors, shutters, and the like. 
     The system  1  comprises a loading magazine  3  arranged for loading onto the caulking machine  1  section bars  4  ( FIG. 5 ) that have not yet been machined, for example extruded aluminium sections, arranged, once they have been finished, for being assembled to make a casing  2 . 
     The loading magazine  3  is provided with gripping means, which are not shown, which are arranged for firmly gripping the section bars  4  and for conveying the latter to a cutting/milling centre  5  positioned downstream of the loading magazine  3 . 
     The cutting/milling centre  5  is arranged for cutting and milling the unworked section bars  4  firmly gripped by the aforesaid gripping means. 
     The system  1  further comprises an unloading magazine  6  positioned downstream of the cutting/milling centre  5  and arranged for receiving the semifinished section bars  4  from the latter. 
     The unloading magazine  6  is provided with detecting means, that is not shown, arranged for detecting the presence of reject section bars  4 . 
     If the detecting means detects the presence of reject section bars  4  the latter are conveyed by a conveyor belt  7  to a removal zone  8  where they are removed by an operator  11 . 
     The system  1  further comprises a handling station  9 , facing the unloading magazine  6 , and provided with a first anthropomorphic robot  10 , for example an anthropomorphic robot with six controlled axes. 
     The first robot  10  is arranged for removing the semifinished section bars  4  from the unloading magazine  6 , positioning the semifinished section bars  4  in a cleaning station  12  that eliminates possible chips present at the ends of the semifinished section bars  4  that could compromise successive assembly thereof, and for loading, without resting, the section bars  4  that have just been finished by the cleaning station  12 , in a drawer, which is not shown, of a buffer magazine  13 . 
     The buffer magazine  13  is provided with a plurality of drawers, arranged for each containing a group of section bars  4  intended for making a determined casing  2 . 
     In an embodiment of the invention, the buffer magazine  13  comprises thirty-six drawers. 
     The buffer magazine  13  comprises a loading side  15  where the section bars  4  removed from the unloading magazine  6  are positioned by the first robot  10  and an unloading side  16 , from which the section bars  4  are unloaded, as will be disclosed below. 
     For example, in use, a pair of full drawers are positioned on the unloading side  16 , each comprising a casing  2  to be assembled. 
     The system  1  further comprises a supervisory computer  14  arranged for controlling the buffer magazine  13 . 
     In particular, the supervisory computer  14  assigns a first free drawer of the buffer magazine  13  to a group of section bars  4  coming from the unloading magazine  6  and arranged for making a determinate casing  2 . 
     The system  1  further comprises a machine tool  200  arranged for assembling and machining the section bars  4  for making the casings  2 . 
     The machine tool  200  comprises a first manipulating unit  17 , provided with a second anthropomorphic robot  18 , between the handling station  9  and the first manipulating unit  17  there being interposed the buffer magazine  13 . 
     The second robot  18  is provided with gripping means arranged for removing the section bars  4  contained in a full drawer positioned on the unloading side  16  of the buffer magazine  13 , positioning them one at a time on an assembly unit  19  and subsequently arranged for inserting into the latter corner joints  38  ( FIG. 6 ) removed from a corner joints magazine  39 . 
     It should be noted that the drawers that have just been emptied are transferred from the unloading side  16  to the loading side  15  of the buffer magazine  13  to be filled with further section bars  4 . 
     Returning to the assembly unit  19 , shown schematically in  FIGS. 2 and 3 , this is arranged for supporting, centering and assembling the section bars  4 . 
     The assembly unit  19 , which is rotatable around a rotation axis Z, comprises a supporting frame body  20 . 
     The supporting frame body  20  comprises a first frame  21  and a second frame  22  that are opposite one another, each arranged for supporting and assembling the section bars  4  and supported by a support  201  mounted on a motor  202 . 
     Subsequently there is disclosed in detail only the first frame  21 , inasmuch as the second frame  22  is substantially and structurally similar to the latter. 
     The first frame  21 , shown in  FIG. 2 , comprises grasping means  40  arranged for grasping and moving the section bars  4 . 
     The grasping means  40  comprises first grasping means  51 , second grasping means  52 , third grasping means  53  and fourth grasping means  54  arranged for each grasping a respective section bar  4 . 
     The first grasping means  51 , the second grasping means  52 , the third grasping means  53  and the fourth grasping means  54  are respectively positioned along a first side  41 , a second side  42 , a third side  43  and a fourth side  44  of the first frame  21 . 
     The first frame  21  further comprises a centering device arranged for centering the section bars  4  on the first frame  21  to give precise references to the second robot  18 . 
     The centering device comprises first centering means  46 , second centering means, third centering means and fourth centering means, that are not shown, positioned substantially parallel to the first side  41 , to the second side  42 , to the third side  43  and to the fourth side  44  and substantially opposite respectively the first grasping means  51 , the second grasping means  52 , the third grasping means  53  and the fourth grasping means  54 . 
     Only the first centering means  46  is disclosed below inasmuch as the second centering means, the third centering means and the fourth centering means are substantially, structurally and functionally similar. 
     The first centering means  46 , shown schematically in  FIG. 4 , is arranged for defining a preset centering position W on the first work plane  21  for a first section bar  36 . 
     The first centering means  46  is provided with compensating means  110  comprising a first abutment  27  and a second abutment  28  that are movable towards and away from one another through an forward and backward stroke of a preset length, along an operating direction X. 
     The first abutment  27 , being substantially L-shaped, comprises a first active surface  29  arranged, in use, for contacting a first end  31  of the first section bar  36 . 
     The second abutment  28  comprises a base element  34  connected by elastic means  35  to a compensating element  66 , arranged for compensating possible dimensional variations of the section bars  4 . 
     The compensating element  36  is in fact supported for sliding by guide means  32 , associated with the base element  34 , and the compensating element  36  is movable along the operating direction X with respect to the base element  34 . 
     The compensating element  66  comprises a second active surface  30 , facing the first active surface  29  and arranged for contacting a second end  33  of the section bar  4  opposite the first end  31 . 
     The first active surface  29  and the second active surface  30  cooperate to define the centering position W for the first section bar  36 . 
     The operation of the first centering means  46  is disclosed below. 
     Initially, the second robot  18  removes from the buffer magazine  13  a first section bar  36  and a second section bar  56  and delivers the first section bar  36  and the second section bar  56  respectively to the first grasping means  51  and to the second grasping means  52 , which grasp the first section bar  36  and the second section bar  56 , without locking them. 
     It should be noted that once the first section bar  36  and the second section bar  56  have been grasped by the first grasping means  51  and by the second grasping means  52 , both the first grasping means  51  and the second grasping means  52  proceed substantially simultaneously to centre the respective section bars; the operation of the first centering means  46  only is disclosed below inasmuch as the second centering means operates in a substantially similar manner. After the first section bar  36  has been grasped by the first grasping means  51 , the first centering means  46  is driven, for example by an actuating means, to position the first abutment  27  and the second abutment  28  in the preset centering position W. 
     Still subsequently, the first grasping means  51  takes the first end  31  and the second end  33  of the first section bar  36  against the first centering means  46 , which positions the first section bar  36  in the desired centering position W with respect to the first frame  21 . 
     Possible dimensional variations of the first section bar  36 , due, for example, to thermal dilation/contraction, imprecise machining or the like that would compromise correct centering of the first section bar  36  on the first frame  21  are compensated by the compensating element  66 , that is movable towards/away from the base element  34  along the operating direction X. 
     Once centred, the first section bar  36  is locked firmly by the first grasping means  51  and the first centering means  46  is positioned in a rest position. 
     Subsequently, the second robot  18  inserts into suitable housings, which are not shown, obtained respectively in the first end  31  and in the second end  33  of the first section bar  36  a pair of corners joints  38  removed from the corner joints  39  magazine and into further housings that are not shown, obtained respectively in a third end  57  and into a fourth end  58  of the second section bar  56  a further pair of corner joints  38  ( FIG. 6 ). 
     It should be noted that in the case of section bars provided with thermal break, inserting four corners for each section bar can be provided. 
     Subsequently, a third section bar  59  and a fourth section bar  60  that are opposite one another and interposed between the first section bar  36  and the second section bar  56  are loaded and centred on the first frame  21  in a similar manner to what has been disclosed above. 
     Still subsequently, the third grasping means  53  and the fourth grasping means  54 , and with the third grasping means  53  and the fourth grasping means  54  the third section bar  59  and the fourth section bar  60  are moved substantially parallel to the axis Z towards the second section bar  56  by the first grasping means  51 , and then by the first section bar  36 , moved in the direction indicated by the first arrow F 1 . 
     In this way the first section bar  36 , the second section bar  56 , the third section bar  59  and the fourth section bar  60  are compacted until the first section bar  36 , the second section bar  56 , the third section bar  59  and the fourth section bar  60  form the casing  2 . 
     It should be noted that the information on the number and type of corner joints to be used is supplied to the second robot  18  by the supervisory computer  14 . 
     After the casing  2  has been compacted, the assembly unit  19  rotates around the rotation axis Z thereof by about 180°, in such a way that, on the one side, the first frame  21  faces a second manipulating unit  67  arranged for subjecting the section bars  4  to a desired machining, such as, for example, caulking, gluing, broaching, drilling, screwing, and on the other side, the second work plane  22  faces the second robot  18 . 
     In this way, whilst the second manipulating unit  67  performs the aforesaid machinings, the first manipulating unit  17 , by the second robot  18 , removes further section bars  4  contained in a further full drawer of the buffer magazine  13  positioned on the unloading side  16 , positions the further section bars  4  one at a time on the second work plane  22 , and assembles the further section bars  4  in a similar manner to what has been disclosed previously. 
     The second manipulating unit  67  comprises a third anthropomorphic robot  68 , provided with a caulking and gluing device  78 , shown in  FIGS. 11 to 13 , arranged for caulking and gluing the first corner  71 , the second corner  72 , the third corner  73  and the fourth corner  74  of the casing  2 . 
     The caulking and gluing device  78  comprises a fixing flange  76 , having a substantially circular shape, arranged for being fixed through threaded connecting means to the third robot  68 . 
     With the flange  76  there is associated a connection  77  arranged for supporting by means of a plurality of tubular elements  78  a framework  79 , between the connection  77  and the flange  76  there being interposed elastic elements  80 . 
     The framework  79  is arranged for supporting respectively at a first end portion  81  and at a second end portion  82  a first caulking clamp  83  and a second caulking clamp  84  arranged for caulking respectively section bars devoid of or provided with thermal break. 
     Only the first clamp  83  is disclosed below, inasmuch as the second clamp  84  is substantially and functionally similar to the latter. 
     The first clamp  83  comprises a pair of jaws  85  that are rotatable around pin means  86 . 
     The pin means  86  is associated with and projects from the framework  79  and is arranged, in use, for removably engaging seat means  87  obtained in the supporting frame body  20  of the assembly unit  19 . 
     In this way, in use, the caulking forces generated by the first clamp  83  are discharged onto the supporting frame body  20  and not onto the third robot  68 . 
     Each jaw  85  further comprises cam means  90  each arranged for engaging a roller  91 . 
     The roller  91  is moved by a presser  92  driven by a piston  94  and slidable along a guide of the framework  79 . 
     In this way, by driving the presser  92  the roller  91  is forced to slide along the cam means  90 , closing and/or opening the jaws  85 . 
     Each of the jaws  85  further supports a caulking cutter  96  at an end thereof. 
     The caulking and gluing device  78  further comprises a nozzle  97  arranged for injecting into holes, which are not shown, obtained in the section bars  4  a desired quantity of glue, removed from a doser that is not shown and arranged for fixing the section bars  4  in a stable manner. 
     In an embodiment of the invention, which is not shown, the third anthropomorphic robot  68  is provided with a drilling unit arranged for drilling said section bars  4 . 
     In a further embodiment of the invention, which is not shown, the third anthropomorphic robot  68  is provided with a broaching machine arranged for inserting broaches into the section bars  4 . 
     In a still further embodiment of the invention, which is not shown, the third anthropomorphic robot  68  is provided with a screwing head. 
     In another embodiment of the invention, which is not shown, also the second robot  18  can be provided with a caulking and gluing device, with a drilling unit, with a broaching machine, and with a screwing head. 
     Once the casing  2  has been fixed stably, the third robot  68  rotates and drives a safety switch that stops the caulking machine  1  and opens an access door  100 . 
     During opening of the access door  100  a printing device  101  prints a recognition label on the casing  2  that has just been made. 
     Subsequently, the casing  2  that has just been made can be removed from the first frame  21 . 
     Once the casing  2  has been unloaded, the operator  11  presses an end-of-unloading switch that closes the access door  100  and gives a signal to the assembly unit  19  by the supervisory computer  14  to rotate the supporting frame body  20  to enable the second manipulating unit  67  to fix the further casing  2  that was previously assembled by the second frame  22  and by the second robot  18 . 
     Upstream of the first manipulating unit  17  there can also be provided a spreading unit arranged for spreading a seal on the end portions of the section bars  4 . 
     It should be noted that owing to the invention it is possible to make a highly automated machine tool that enables the metal section bars  2  to be centred, assembled and caulked automatically. 
     Lastly, it should be noted that owing to the aforesaid invention it is possible to make a particularly versatile machine tool inasmuch as depending on the equipment mounted on the second manipulating unit  67  it is possible to subject the section bars  4  to a plurality of machinings such as caulking, gluing, drilling, broaching and screwing.