Patent Publication Number: US-2011061507-A1

Title: Pipe machining device

Description:
The invention consists of a pipe machining device in the form of a pipe cutting device, pipe gripping device, or pipe rectangular end facing device as described in claim  1 . 
     Examples of this type of pipe cutting device are described in the following documents: CH 372 202, DE 101 34 269 B4, EP 1 138 125 B1, US 2005/0097752 A1. Examples of a device for machining pipe ends are described in DE 101 20 185 B4, EP 0 855 944 B1, U.S. Pat. No. 6,637,304 B2, and U.S. Pat. No. 6,968,761 B2. Pipe end machining can involve beveling and/or rectangular end facing. Rectangular end facing means that the end surface of a pipe is machined in such a way that it is precisely perpendicular to the pipe&#39;s lengthwise axis. 
     DE 30 02 887 A1 and DE 30 17 688 A1 include examples of vortex tubes that generate a vortex current and separate it into a warm air current and a cold air current, such that the cold air current moves within the warm air current in a direction axially opposed to the warm air current. The principle was discovered in 1930 by French physicist Georges Ranque. The cold air current can be used, when machining workpieces, to cool them and the machine tools used on them while they are milled, drilled, ground, and rotated. To date there are no reports of using vortex tubes to generate cold air for cooling workpieces or machine tools on pipe machining devices where the tool is positioned rotatably in a machining device that itself can be rotated around the pipe that is being machined. 
     The invention should make it possible to achieve the goal of longer tool use times, with a tool that is positioned so that it can rotate and can also simultaneously be moved at least 360° around the pipe to be machined. 
     This solution is achieved using the version of the invention described in claim  1 . 
     Additional versions of the invention are included in the subsequent claims. 
     During the invention process it was determined that machining, and especially cutting pipes, normally does not cause temperatures high enough to damage the tool, but nonetheless the use time, or lifespan, of the tool can be extended if the tool is cooled during use. 
     The use of a liquid coolant to cool tools can have the disadvantage that the tool and the workpiece, and often the entire work area, must be cleaned again after cooling, in order to remove the liquid coolant along with any residue of the pipe material and/or abrasion particles from the tool that may be contained in it. In addition, the liquid coolant must be filtered before it can be reused or discarded. 
     During the invention process it was determined that simply cooling with refrigerated or unrefrigerated cold air can significantly extend the lifespan, or use time, of a machine tool. Pressurized air leaves no dirt behind. Cold air, both refrigerated and not, is already used in areas other than pipe machining equipment. For the aforementioned types of pipe machining devices, the use of a coolant in either liquid or air form had not been suggested to date, which may be due to the lower temperatures involved in pipe machining, but also to the fact that, in the aforementioned types of pipe machining devices, not only can the tool be motor-driven—if it is a circular saw blade, an end cutting disc, or something similar—but the tool shaft itself is located in a machining device that can be moved at least 360° around the pipe, so delivering the coolant is difficult. 
     The invention provides a simple process and means of cooling the tool and/or the pipe being machined, without requiring rotating elements, regardless of whether or not the machining device in which the rotating tool is located can itself be rotated around the pipe. 
     With one previously mentioned advantageous execution form of the invention, a cold air blower device with a vortex tube is located on the rotatable machining device in which the tool is placed. The cold air outlet of the vortex tube, or the outlet of a cold air outlet tube extending from the cold air outlet, is directed toward the tool and/or toward the area of the pipe to be machined. In this version, the cold air blower device also includes a device for cooling the pressurized air used as the cold air supply. 
    
    
     
       The invention is described below, with reference to the attached drawings and using the previously described execution forms as examples. The drawings show: 
         FIG. 1  a perspective view of a pipe machining device according to the invention, seen diagonally from the front, 
         FIG. 2  a front view of the pipe machining device from  FIG. 1 , 
         FIG. 3  a vertical axial cross-section along the plane from  FIG. 2 , 
         FIG. 4  a cam-type drive for radial movement of a sliding element to which a cutting tool is attached, 
         FIG. 5  the principle of a vortex tube, which is used to cool pressurized air according to the vortex current principle, 
         FIG. 6  a schematic of another way to execute the invention, and 
         FIG. 7  a schematic of yet another way to execute the invention. 
     
    
    
     The pipe cutting device shown in the drawings includes a gripping device  2 , in the form of a vise, for example, for gripping the pipe to be cut, and a machining device  4  for machining a pipe held in the gripping device  2 . The machining device  4  includes a guide ring  6 , which is connected to the main body  8  of the gripping device  2  in such a way that it cannot move and defines a rotation axis  10  ( FIG. 3 ), around which a rotating body  12  of the machining device  4  attached to the guide ring  6  can be rotated at least 360°. The rotation axis  10  of the rotating body  12  is aligned with the center axis of the pipe to be cut, defined by the gripping device  2 . 
     The rotating body  12  includes a sliding element  14 , which slides easily in the rotating body  12  radially to the rotation axis  10  of the rotating body  12 . On the sliding element  14  is a tool shaft  20 , which is positioned so that it can rotate and which can be driven by a motor  16  through a gear  18 . A tool  24  can be attached to the shaft  20  in such a manner that it does not rotate with respect to the shaft, but rotates with it. The rotation axis  22  of the tool shaft  20  is parallel to the rotation axis  10  of the rotating body  12 . 
     The tool  24  is preferably disc-shaped, such as a circular saw blade or an end cutting disc for cutting a pipe. The tool  24  could also be another type of grinding wheel or a different rotating tool for beveling or rectangular end facing of a pipe&#39;s end surface. 
     The drawings show the machining device  4  in a zero rotation direction position. 
     Here the tool  24  moves radially downward away from the pipe to be cut, and a protrusion  26  connected to the sliding element  14 , which contains the motor  16  and a gear  18  or consists at least partially of a motor housing, extends outward and downward from the sliding element  14  like a lever. The protrusion  26  can be provided with one or two grips  28  and  30  on its outer end that is farthest away from the sliding element  14 . The protrusion  26  extends crosswise, preferably radial, to the rotation axis  10  of the rotating body  12 . 
     At the zero rotation direction position shown in the drawings, the sliding element  14  is held by a guide bolt  32  fastened to it in a cam groove  34  of a guide track  36  extending 360° around it. This is shown in the schematic in  FIG. 4 . The guide bolt  32  is fastened to the sliding element  14 . The guide track  36  is located on the guide ring  6  or on a cam disc fastened with a non-rotating connection to the guide ring  6 . Segment  37  of the guide track  36  on both sides of the cam groove  34  can be circular, with the circle&#39;s center point in the rotation axis  10  of the rotating body  12 . 
     If the rotating body  12  is moved outward from the zero rotation direction position as it rotates around its rotation axis  10 , the guide bolt  32  is raised up out from the cam disc  34  on the guide track segment  37 , as shown in  FIG. 4  at the shaded position  32 - 2  of the guide bolt  32 . The guide track segment  37  has a larger radius than the shaft groove in the cam disc  34 . This lifting of the guide bolt  32  out from the cam disc  34  on the radially higher guide track segment  37  causes the sliding element  14  to be lifted up by a corresponding distance, which also lifts the tool  24  into a pipe to be machined, e.g., cut off. With continued rotation of the rotating body  12 , the sliding element  14 , and the cutting tool around the rotation axis  10  of the rotating body  12 —in rotation direction  38 , for example—the cutting tool  24  remains in the wall of the pipe being cut, so that the pipe is machined, e.g., cut. At the end of 360° of rotation by the rotating body  12 , the guide bolt  32  goes back into the cam disc  34 , which makes the tool  24  with the sliding element  14  fall radially away from the pipe. Now the machining device  4  with the rotating body  12  and the tool  24  can either be rotated farther in the same direction or be rotated back in the opposite rotation direction. 
     These possibilities, described with reference to  FIG. 4 , for forward radial movement of the tool  24  radially to the pipe to be machined, e.g., cut off, and then away from said pipe are only one of many possible execution forms. Other forms may also be used, depending on the current state of the technology. 
     The rotation direction  38  of the rotating body  12  together with the sliding element  14  and the tool  24  is preferably opposite to the rotation direction  40  of the tool  24 , as shown, for example, in  FIG. 2  by arrows  38  and  40 . As an example, in the front view of the cutting device  4 , the rotation direction  38  of the rotating body  12  is shown as clockwise and the rotation direction  40  of the tool  24  as counterclockwise. 
     A protective cap  42  can be placed in front of the tool  24 , in order to prevent a person from accidentally stopping the tool  24  when the pipe machining device is switched on and to catch chips that are shaved off and thrown away from the pipe by the tool  24 . 
     The protective cap  42  is swivel-mounted on the sliding element  14  around a swivel axis  54  that is parallel to the rotation axis  22  of the tool shaft  20 , against the spring tension of a spring (not shown), in the direction away from the rotation axis  10  of the rotating body  12 . 
     If the sliding element  14  together with the tool  24 , as they have previously been described, for example, are moved radially, then the tool  24  goes toward the pipe and makes contact with the pipe wall, so that the pipe pushes the protective cap  42  radially away, causing the protective cap  42  to swivel around its swivel axis  54 . 
     According to the invention, the rotatable machining device  4  is equipped with a cold air blower device  60 , whose cold air outlet  62  is directed toward the area where the tool  24  is working and/or toward the machining area of the pipe to be machined by the tool, in order to blow pressurized cold air  64  on it. 
     The cold air blower device  60  can be integrated into the rotatable machining device  4  or attached to it. 
     For feeding pressurized air into the pressurized air blower device  60 , a flexible pressurized air hose  66  is provided, with one end connected to a pressurized air inlet  68  of the pressurized air blower device  60 , and the other end connected or connectable to a pressurized air source  70 . The pressurized air source  70  can be a pressure regulator, pressure reducer, pressurized air supply, or air compressor, for example. 
     The cold air for the invention can be unrefrigerated or, preferably, refrigerated pressurized air. 
     According to a previously described execution form of the invention, the cold air blower device  60  has a vortex tube  72 , which uses the vortex current principle to divide the pressurized air current  74  from the pressurized air inlet  68  into a warm air current (or hot air current) and a cold air current.  FIG. 5  in the drawings shows the principle of such a vortex tube  72 . 
     As shown in  FIG. 5 , the vortex tube  72  contains a vortex generation chamber  76 , into which the pressurized air inlet  68  empties. A warm air pipe  78  extends away from the vortex generation chamber  76  in one axial vortex direction, and a cold air outlet channel  80  in the opposite axial vortex direction. The cold air outlet channel  80 , as shown in  FIG. 5 , or an extension  81  from it as shown in  FIG. 6 , leads to the aforementioned cold air outlet  62 . The extension  81  can be a pipe or hose. The pressurized air  74 , which flows through the pressurized air inlet  68  in the vortex generation chamber  76 , is placed into rotation in the chamber and rotates in an axial direction through the warm air pipe  78 , such that it is pressed against the inner surface of the warm air pipe  78  and heated. At the end of the warm air pipe  78  away from the vortex generation chamber  76 , a smaller portion  82  of the warm air vortex current  84  flows out through a warm air outlet  86  from the warm air pipe  78 . The remaining portion  88  of the warm air vortex current  84  is channeled back forcibly, rotating at a low speed, through the middle of the warm air vortex current  84  in the opposite axial direction, so that it gives heat to the faster rotating warm air vortex current  84 . This makes the back-rotating portion  88  (cold air vortex current) colder than the original pressurized air  74 , until it then flows out as cold air  64  through the cold air outlet channel  80  and then from the cold air outlet  62 . 
     The vortex tube  72  is shown with a noise muffler  90 . 
     According to another execution form of the invention, shown schematically in  FIG. 7 , the cold air blower device can consist of a blower pipe  94  attached to the rotatable machining device  4 , one end of which is directed toward the tool  24  and/or toward the pipe to be machined and acts as the cold air outlet  62 , and the other end of which is connected via a pressurized air hose  66  to a pressurized air source  70 . Between the pressurized air source  70  and the pressurized air hose  66 , a cooling device  96  can be attached for cooling the pressurized air. 
     At the location of a blower pipe  94 , a nozzle fitting can be provided in the rotatable machining device  4 , whose nozzle outlet acts as the cold air outlet  62 .