Abstract:
Composable machine tool for chip removal, on major workpieces, within wide diameter and/or great length clearance holes, made up of a shaft ( 1 ) upon which a machine base, controlled by a first engine ( 50 ) for the rotation movement and by a second engine for the translation movement, upon which are mounted the design tool elements. On the shaft ( 1 ) two support bearings ( 15 ) are mounted on both sides of the workpiece ( 29 ), all have spokes ( 16 ) each of which have radial slots ( 17 ) in which the groups ( 33 ) are inserted, regulated and locked to tighten the workpiece, on the shaft, a hydraulic jack ( 34 ) is mounted at least on one side, at the two extremities of the shaft ( 1 ), two slotted shoulders ( 40 ) are mounted to allow the jack ( 34 ) to exert the necessary pressure to lock the workpiece.

Description:
BACKGROUND OF THE INVENTION 
   The composable machine tool subject of the present invention is a machine for chip removal within wide diameter and great length clearance holes, made up of a shaft upon which are mounted a ring, that may shift on the shaft itself, a machine base that can rotate on the ring, two flanges that are attached to the machine base that bear the tool design elements, an engine for the rotation movement and an engine for the translation movement. 
   The machine described in the present invention is a composable machine, it has been studied to allow the operator to easily and precisely install it on major mechanical structures, avoiding the disassembly of the aforesaid structures, transportation with huge vehicles in specialised centres in order to repair them, thus saving time and money, advantages, these that were impossible to obtain with traditional machine tools. 
   The machine is studied to process workpieces with wide diameter clearance holes and to process workpieces with great length clearance holes. 
   Moreover, the aim of the present invention is to obtain a machine that can also be used in water. 
   A limit of the machines now on the market is that they are not able to process wide diameter workpieces or great length workpieces, if the said workpieces are not disassembled and transported in specialised centres with enormous traditional equipment. 
   In fact the chip removal machines such as lathes, drilling machines, cross cutting machines in order to work precisely need extremely rigid shafts to support without bending, the stress that the cutting tool exerts and therefore they must be very robust. If the shaft rigidity is not adequate, the stress that the machine must exert in the point in which the tool cuts influences the machine precision. Therefore the quality of the machined surfaces decreases and it is not what one expects. 
   There are machines on the market that can operate on the spot without disassembling the workpieces that are to be repaired, above all if these are large and are mounted on large mechanical structures. One of these machines is described in U.S. Pat. No. 4,268,196 that allows only drilling. It does not however allow precision turning or boring. 
   SUMMARY OF THE INVENTION 
   The present invention instead allows precision works on major (both diameter-wise and length-wise) workpieces, because the shaft before the machine begins to operate, is set into traction, thus reducing its flexibility. The shaft traction is determined by the fact that the workpiece is fastened between two supporting plates that hold the said shaft in traction during the entire processing period. 
   The backings pushed by the external slides of one or two jacks pin down through the column heads the workpieces. The internal slides of the jack in order to support the pressure exerted on them must be fastened by slotted shoulders fastened the shaft that is subject to the tensile stress equal to the pressure exerted by the jacks on the workpiece. The workpiece is firmly held, fastened by the jack pressure and contemporarily the machine tool shaft is kept in traction by a force that is equal and contrary to the pressure exerted by the jacks. 
   As an effect of this tensile stress the shaft of the present portable machine is more rigid than that of a traditional machine and therefore allows turning and boring with the necessary precision on workpieces with wide diameter and great length clearance holes. 
   The main characteristic of the present invention is to make a composable chip removal machine tool on major workpieces, within wide diameter and/or great length clearance holes, made up of a shaft upon which a machine base is mounted, controlled by a first motor for the rotation movement and by a second motor for the translation movement, upon which are mounted the tool design elements. The machine base is made up of a bush, that presents a groove that receives, like a key, the rack screwed on the shaft by allen screws, and by a rotating ring, mounted on the bush with two airtight bearings. The bush can translate on the shaft, the shaft has a tubular section, on the rotating ring are mounted, on both sides of the rotating ring, two flanges attached to the machine base that hold the tool design elements and that have a larger diameter than the rotating ring itself, tool design elements are mounted through screws on the flanges, on the shaft two support bearings are mounted on both sides of the workpiece, all have spokes each of which have radial slots, in which are inserted, regulated and locked the grippers to tighten the workpiece, on the shaft, at least on one side a hydraulic jack is mounted, at the two extremities of the shaft two slotted shoulders are mounted to allow the jack to exert the necessary pressure to lock the workpiece. In this manner, the machine shaft is set in traction between the slotted shoulders and it firmly locks with the supporting bearings the workpiece. The machine shaft, set in traction has a greater rigidity and the machine allows operating upon large diameters and/or great lengths workpieces, without the danger that the shaft may be subject to peak loads. 
   Another characteristic of the machine subject of the present invention is that the grippers that insert themselves in the slots to tighten the workpiece are built each by the first threaded bushes that are locked with ring nuts that are screwed on the external surface of the first threaded bushes. Both the first threaded bushes and the ring nuts have on the external rim holes to allow appropriate spanners to adequately fasten the first threaded bush and metal ring nut on the bearing. They are positioned with the axis of the hole of the first threaded bush in correspondence of the average diameter of the workpiece. Within the first threaded bush, a second threaded bush is screwed onto the external surface that is screwed within the first threaded bush. Before fastening the second bush in the first threaded bush, on the second bush a ring nut is fastened. Both the second bush and the ring nut have holes to allow the fastening with appropriate spanners. In the second bush, a column fitted with spacers placed between the column head and the second bush head. The second bush of each spoke of the supporting bearings is screwed or unscrewed until all heads do not touch the workpiece. 
   The gripper that fasten the workpiece allow to be moved radially along the slots, in this manner the gripper are moved into the best position in order to be pressed onto the workpiece. Eventual workpiece asymmetries are overcome by regulating each gripper differently on the slots of each single supporting bearing. 
   Another characteristic of the machine subject of the present invention is that the engines are hydraulic engines driven by a hydraulic power unit connected to them through tubes. Hydraulic engines allow the use of the machine in water. The machine tools present on the market are driven by electric engines that do not allow, unless they are given heavy and expensive water resistant casings, their underwater use because of the obvious danger of using electrical current underwater. The possibility, therefore, to operate underwater on workpieces with wide diameter and great length clearance holes, presents insurmountable difficulties for other machines. The present machine because of its hydraulic engines does not present the inconveniences of the other portable machines tools and, furthermore, it has the necessary shaft rigidity to carry out the operations with due precision. 
   Another characteristic of the machine subject of the present invention is that the toothed rack is mounted through alien screws on the shaft, the toothed rack protrudes from the shaft diameter and is grafted on as a key connects the shaft to the ring and to the supporting bearing hub. The toothed rack itself is used as a key, thus simplifying the construction. 
   Another characteristic of the machine subject of the present invention is that rotating ring is mounted on the bush through airtight bearings. 
   Another characteristic of the machine subject of the present invention is that the motors are contained in a casing, in order to avoid that the chip may end up in the engines, damaging them. 
   Another characteristic of the machine subject of the present invention is that the motor for translation movement drives a worm gear that moves a gear wheel that meshes with the toothed rack. The translation movement is a continuous movement with no jerks, to avoid acceleration that may turn into dangerous stress on the tools and generally on the machine. 
   Another characteristic of the machine subject of the present invention is that the tubes are wound and unwound in a hose reel as the machine base draws nearer and as it moves away. To avoid that the tubes obstruct processing, they are collected and unwound according to requirements. 
   Another characteristic of the machine subject of the present invention is that slotted shoulder is fastened by a bolt that is screwed on the threaded hole present on the shaft and on the pivot. The slotted shoulder is, therefore easily, with only one bolt, fastened on the shaft and on the pivot. 
   Another characteristic of the machine subject of the present invention is that the slotted shoulder is extracted by a bolt that is screwed in the threaded hole present on the slotted shoulder itself, that having a larger diameter than the threaded hole, pushes externally the slotted shoulder itself. Just as easily the slotted shoulder is extracted, unscrewing the clamp bolt and inserting the apposite bolt for the greater diameter extraction of the threaded hole present on the shaft and on the pivot. 
   Another characteristic of the machine subject of the present invention is that on the two flanges two plates that have a larger diameter than the two flanges endowed with holes upon which the tool design elements are screwed. With the interchangeable plates, it is possible with a greater diameter, to operate on larger workpieces. 
   Another characteristic of the machine subject of the present invention is that the space between the bush and rotating ring forms the lubricant tank of the machine base. The bush has a lubricant hole for the bush itself, for the shaft, for the rack, for the rotating ring. The lubricant is prevented from spilling by the seals. To improve the machine yield, it is also lubricated. 
   Other invention characteristics and advantages will appear clearly from the description hereafter of certain realisation ways given as an unrestricted example in  FIGS. 1 ,  2 ,  3 ,  4 ,  5 ,  6 ,  7 ,  8  and  9 . 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  represents a section of the machine tool subject of the present invention. 
       FIG. 2  represents a view of a supporting bearing. 
       FIG. 3  represents a section of a supporting bearing 
       FIG. 4  represents a section of the final part of the clamping system. 
       FIG. 5  represents a section of the clamping ring during the assembly. 
       FIG. 6  represents a different section of the final part of the clamping system. 
       FIG. 7  represents a section of the clamping ring during the disassembly. 
       FIG. 8  represents a section of the machine tool subject of the present invention of only one jack. 
       FIG. 9  represents a section of the machine tool subject of the present invention, which mounts the processing tools. 
   

   DESCRIPTION OF THE PREFERRED EMBODIMENTS 
   In  FIG. 1 , a machine base made up of a bush  2  and of a rotating ring  7  is mounted on a tubular sectioned shaft  1 . To improve corrosion resistance the shaft surface is chromium plated. On shaft  1  a toothed rack  3  is mounted, which is inserted in the groove made in shaft  1  and that is fastened to it through a series of alien screws  4 . The toothed rack  3  serves also as a key for bush  2 , because in bush  2  a groove  5  is made that receives the rack key  3 . To improve corrosion resistance and its duration, bush  2  is bronzed. 
   Because rack  3  is working in groove  5 , it does not allow the relative rotation between shaft  1  and the bush  2 . It is instead possible to have translation movement relative to the sense of the longitudinal direction of shaft  1  between the shaft  1  itself and bush  2 . 
   Two bearings  6  that support a rotating ring  7  are mounted on bush  2 . The bearings  6  are airtight and are fastened by a flange  8  and by a flange  9 . The space between the bush  2  and the rotating ring  7  creates the lubricant tank of the machine base. The bush  2  has a hole  69  for the lubrication of the bush  2  itself, of shaft  1 , of rack  3 , of the rotating ring  7 . The lubricant cannot fall out because of the seals  71 . 
   The two  8  and  9  flanges are mounted on one side and the other of the rotating ring  7  through bolts  10 , which make it integral with the rotating ring. The two flanges  8  and  9  have a greater diameter that the rotating ring  7 . The flanges  8  and  9  in the part that comes out from the rotating ring  7  have a series of holes, which allows through bolts  11  to mount tool design elements  12 . Flanges  8  and  9  also accomplish the task of locking the bearings  6  in the housing of the rotating ring  7 . 
   Flanges  8  and  9  are used both to fasten the centring elements of the machine on workpiece  29  and to fasten the elements  72  that bear the cutting tools  73  (see  FIG. 9 ). 
   On flanges  8  and  9  are mounted some tool design heads ( 12 ) that carry threaded pivots  13  endowed with ring nuts  14  that allow though their movement to centre the machine within workpiece  29 . 
   The ring nuts  14  are manoeuvred until the centres  58  do not touch the internal surface of workpiece  29 , centring shaft  1  on workpiece  29 . 
   After the centring, the supporting bearings  15  are inserted on both sides of shaft  1  (see also  FIGS. 2 and 3 ). 
   The supporting bearings  15  have spokes  16 , each of which has radial slots  17 , and stiffening flanges  18 . On each hub  19  of each supporting bearing  15  are made grooves  20  that receive the rack key  3 . In this manner the supporting bearings  15  can shift on the shaft but not rotate. 
   In each slot  17  grippers  33  are inserted to fasten the workpiece. The grippers  33  in order to fasten the piece can be regulated according to the diameter of workpiece  29  and once they are regulated in the correct position, they are locked. The grippers to fasten the piece are made up of the first threaded bushes  21  that are locked with the rings  22  that are screwed on the external surface of the first threaded bushes  21 . Both the first threaded bushes  21  and the rings  22  are endowed on the external rim of respectively holes  23  and  24  to allow with opportune spanners to adequately tighten the first threaded bush  21  and the ring  22  on bearing  15 . They are positioned with the axis of the hole of the first threaded bush  21  in correspondence of the average diameter of workpiece  29 . 
   Within the first threaded bush  21  is screwed a second bush  25  threaded on its external surface that is screwed within the first threaded bush  21 . 
   Before screwing the second bush  25  in the first threaded bush  21 , a ring  26  is screwed on the second bush  25 . Both the second bush  25  and the ring  26  are respectively endowed with holes  27  and  28  to allow clamping with opportune spanners. In the second bush  25 , the column  30  is introduced endowed with spacers  31  set between the head  32  of the column  30  and the head of the second bush  2 . The second bush  25  of each spoke  16  of the supporting bearings  15  is screwed or unscrewed until all the heads  32  do not touch the workpiece  29 . Jacks  34  mounted on the extremities of shaft  1  are used to lock the workpiece. 
   Before inserting the jacks  34 , on one extremity or another of the shaft  1 , the spacers  35  are inserted. 
   Shaft  1  at its two extremities has two solid pivots  36  that are inserted with force in shaft  1  itself to strengthen it. 
   Shaft  1  at its extremities (see  FIGS. 6 and 7 ) has on both sides the cuttings  37  and  38  that arrive until the solid pivot  36 . 
   The cuttings  37  and  38  are symmetrical in relation to the toothed rack  3 . 
   On the opposite part of the toothed rack  3 , on the shaft  1  a threaded hole  39  is realised (see  FIGS. 4 ,  5 ,  6  and  7 ). 
   The jacks  34  are opposed on one side by the supporting bearings  15 , through the spacers  35 , and on the other, at the extremity, by the slotted shoulders  40 , for the jack thrust seal, that have two arms  41  and  42  with an opening that is equal to the distance between the cuttings  37  and  38  made on shaft  1  and on the solid pivots  36 . The slotted shoulder  40  has a threaded hole  43  whose diameter is greater than the threaded hole  39  that is on shaft  1 . The slotted shoulder  40  in order to be fastened on shaft  1  is tightened with a bolt  44  that is screwed into the threaded hole  39  that is on shaft  1 . 
   To extract the slotted shoulder  40  the bolt  44  is unscrewed and bolt  45  is inserted that perfectly screws into threaded hole  43  of the clamping hole  40  and that therefore has a greater diameter than the threaded hole  39 . For that reason, the bolt  45 , when it is screwed into the threaded hole  43 , arrives to the threaded hole  39 , but, it having a larger diameter than the aforesaid threaded hole  39 , can not penetrate in it and it will push Shaft  1 , compelling it to move upwards the slotted shoulder  40 . 
   The jacks  34  are composed of an internal slide  46  and an external slide  47 . The hydraulic fluid introduced under pressure through the  48  holes pushes the internal slide  46  against the slotted shoulder  40  and it forces the external slide  47  to push through the spacers  35  the supporting bearings  15  that in turn through the columns  30  fasten the workpiece  29 . The packings  70  guarantee the hydraulic seal of the jacks. To improve head  32  gripping on the columns  32 , one drives the back of the column with a mallet to make the head  32  penetrate and grip better, it is fitted with claw clamps and hardened to increase and improve the grasp on the workpiece  29 . 
   For particular applications the claw clamped and hardened heads  32  may have the form that follows the shape of the workpiece  29 . They are substitutable and, in some case heads  32  can be used to weld on the workpiece that  29 , these heads are disposable, single use. 
   Essentially workpiece  29  is fastened between the supporting bearings driven by the jacks  34  and, therefore, shaft  1  is set into traction between the aforementioned bearings. For safety the external slides  47  that fasten through hydraulic pressure workpiece  29  are mechanically locked and definitively through the ring nuts  49  that are screwed on both sides of the internal slides  46 . Once workpiece  29  is mechanically fastened, the hydraulic pressure that is exerted on the jacks  34  can be eliminated. 
   The hydraulic engine  50  supported by a stirrup  51  is mounted on the bush  2 . The hydraulic engine  50  is stably connected with a gear wheel  52  that meshes with a gear wheel  53  fastened with screws  10  to the machine base  7 . The hydraulic engine  50  allows the rotation movement. 
   On bush  2  is mounted, on a bearing such as engine  50 , a second hydraulic engine  54  that with a worm gear  55  drives a gear wheel  56  that meshes with the toothed rack  3 . The hydraulic engine  54  allows the translation movement. 
   The engines  50  and  54  are closed by casing  57 , in sheet metal or plastic to avoid that the excess chip damages the engines. 
   Through a hydraulic power unit  60  it is possible to send pressurised fluid to the hydraulic engines  50  and  54  and to the jacks  34 . 
   The power unit  60  is started through a hydraulic deflector  59 . The pressurised fluid through tubes  61  and  62  is sent to engines  50  and  54  and to jacks  34 . 
   Through lever  63  the rotation of engine  50  is activated and it transmits the rotation movement to machine base  7  in one direction pushing lever  63  right and in the opposite direction pushing it left. 
   The rotation speed is regulated through a fluxmeter controlled by knob  64 . Through lever  65  engine  54  is started, that through the worm gear  55  and  56  determines the translation movement in one direction pushing the lever  65  right and in the opposite direction pushing it left, the translation speed is instead regulated through a fluxmeter controlled by knob  66 . 
   To avoid that the tubes  62  that supply the rotation engine  50  and the translation engine  54  get entangled, they are wound and unwound in a hose reel  67  that winds the tubes  62  when the machine base draws nearer and unwinds the tubes  62  when they move away. 
   Referring to  FIG. 8  on shaft  1  only one jack  34  is mounted that pushes the workpiece  29  through the columns  30  and the supporting bearings  15  against the slotted shoulder  40  positioned opposite the shaft and on its extremity. Shaft  1  will be therefore set in traction between the slotted shoulder  40  and the jack  34 . For safety, even now the external slide  47  is mechanically locked through ring nut  49  that is screwed on the internal slide  46 . Even in this case, once workpiece  29  is mechanically fastened, the hydraulic pressure that is exerted on jack  34  can be eliminated. 
   The space between the bush  2  and the rotating ring  7  forms the lubricant tank of the machine base. The bush  2  has a clearance hole  69  for lubrication of the bush  2  itself, of the shaft  1 , of the rack  3 , of the rotating ring  7 . The lubricant is prevented from spilling by the seals  71 . The lubricant is poured through the plug  73  arranged on the rotating ring  7 , it goes through the clearance hole  74  reaches the space between the bush  2  and the rotating ring  7  that forms the tank of the lubricant itself. 
   Plates  68  are mounted on flanges  8  and  9  to allow processing of larger diameter pieces. The plates have a greater diameter than the two flanges  8  and  9  and on these plates  68  the tool design elements  13  are screwed. 
   The invention, it must be understood, is not limited to the representation given by the tables but may receive improvements and changes from the man of the art without going beyond the invention area. 
   The present invention allows numerous advantages and overcomes difficulties that could not have been won with the systems today in commerce.