Abstract:
A tool holder includes an insert having an annular channel in fluid communication with an inlet. The insert mounts within a body that provides for rigidly mounting the tool to the machine. Coolant flow through the inlet and annular channel exits the insert through passages directing coolant fluid along the axis of the tool. The passages are annularly disposed about a face of the insert for directing coolant fluid along the tool.

Description:
REFERENCE TO RELATED APPLICATION  
       [0001]     This application is a continuation-in-part of co-pending U.S. patent application Ser. No. 11/098,979 filed on Apr. 5, 2005 which is a continuation in part of Ser. No. 10/197,390 filed on Jul. 17, 2002. 
     
    
     BACKGROUND OF THE INVENTION  
       [0002]     This invention relates to an assembly for directing coolant flow onto a machine tool orkpiece, and specifically to an assembly for directing coolant flow onto a tool at different locations along the rotational axis.  
         [0003]     Typically, in a conventional machining process a stream of coolant is directed onto the cutting tool to maintain a constant temperature. Without coolant flow, friction from the tool and the workpiece generate heat of a degree sufficient to damage the tool. Further, not only would the tool be damaged, but also the quality of the machined surface of the work piece is degraded. For these reasons it is desirable direct a stream of coolant onto a tool during machining operations. Machining produces metal chips that are preferably evacuated from the machining area in order to prevent damage to the tool and work piece. The stream of coolant aids evacuation of metal chips from the work piece during machining.  
         [0004]     Typical arrangements for directing coolant onto a tool include the use of a plurality of hoses arranged to direct fluid onto the tool. These hoses are typically of a semi-rigid design extending around a tool and manually positioned to direct coolant onto a tool. Often during the machining, the work piece or chips bump and contact the coolant lines changing the position of the hose such that the coolant is no longer directed as originally positioned onto the tool. In addition, hoses are often not positionable for providing coolant as desired when machining of relatively deep openings or holes. Further, in some part configurations an adjustable coolant hose is simply not feasible and does not supply and direct coolant flow adequately to the tool.  
         [0005]     It is known in the art to provide a system for directing fluid between the machine and spindle to direct flow. Such systems require expensive and complicated fluid routing mechanisms in order to route coolant fluid substantially near the axis of rotation of the tool. Further, such systems are not easily adaptable to tool changes.  
         [0006]     Accordingly, it is desirable to provide a low cost, easily changeable and configurable coolant directing assembly that directs coolant along the tool without obstructing machining operations.  
       SUMMARY OF THE INVENTION  
       [0007]     An example tool holder secures a tool and includes an insert that defines passages for directing coolant onto a tool during machining operations.  
         [0008]     An example tool holder includes an insert having an annular channel in fluid communication with an inlet defined by the insert pressed into the face of the tool holder. The insert mounts within a body that provides for rigidly mounting the tool to the machine and includes at least one setscrew securing the tool within the tool holder. Coolant flows through the inlet and internal channels and exits the insert through passages directing coolant fluid along the axis of the tool. The passages are annularly disposed about a face of the insert.  
         [0009]     Accordingly, the example tool holder provides easy mounting for existing machinery while directing coolant along the entire length of a tool without complex piping and valving and does not interfere with the work piece tool interface during machining.  
         [0010]     The various features and advantages of this invention will become apparent to those skilled in the art from the following detailed description of the currently preferred embodiments. The drawings that accompany the detailed description can be briefly described as follows. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0011]      FIG. 1  is a cross-sectional view of an example tool holder.  
         [0012]      FIG. 2  if a front view of the example tool holder. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT  
       [0013]     Referring to the  FIG. 1 , an example tool holder assembly  10  holds a tool  15  for use with a machine and includes a body  12  having an inlet  14  through which coolant (indicated by arrows  20 ) flows to lateral passages  16  that are in turn in fluid communication with coolant passages  18 . The coolant passages  18  are in fluid communication with and annular fluid channel  22 . The annular fluid channel  22  is in turn in fluid communication with passages  24  within an insert  34 . The fluid passages  24  direct coolant along the axis  26 . At least two of the coolant passages  24  can be at differing angles  28 ,  30 .  
         [0014]     The differing angles of the passages  24  provide for the direction of coolant along different points of the axis  26 . Further, the fluid passages  24  can be disposed at the same angle or different angles. The angles  28 ,  30  are between 2° and 25° relative to the central axis  26 , with the disclosed example including an angle of 8°. As appreciated, the angle for the fluid passages  24  can vary as is required to direct fluid through to the tool disposed along the axis  26 .  
         [0015]     The inlet  14  is disposed at a rear portion of the body  12 . The body  12  includes a tapered portion  36  that cooperates with a mount portion  38  of the tool body  12 . This configuration is as is known to a worker skilled in the art and may be of differing configuration as is required for the specific application. The inlet  14  is disposed in a rear portion of the body  12  and cooperates with a machine internal coolant system (not shown). In machines equipped with a thru spindle coolant system coolant is provided through the rear of the tool holder  12  to a tool mounted within the inner diameter  42  of the tool holder  10 . At least one setscrew  40  is provided to secure the tool  15  within the tool holder  10 . The tool  15  preferably will mount within the inner diameter  42  of the tool holder  10 . It should be understood that it is within the contemplation of this invention that the tool holder  10  may be modified as is known to a worker skilled in the art to conform and fit differing tool sizes where the inner diameter  42  would be modified to fit tools of differing outer diameters.  
         [0016]     The coolant passages  18  are formed by drilling from the annular channel  22  to the lateral passages  16 . The lateral passages  16  are formed by drilling from an outer diameter of the tool body  12  to communicate with the inlet passage  17 . The lateral passages  16  are then plugged with plugs  56 . The coolant passages  18  and lateral passages  16  are formed with a diameter that does not constrict fluid flow. The larger diameters of the coolant passages  18  and lateral passages  16  provide for the use of a relatively large diameter drill. The larger diameter drills are acceptable for drilling the depth of holes required to communicate coolant to the tool  15 .  
         [0017]     However, the large diameter holes cannot be utilized effectively within the insert  34 . Larger outlet openings result in a large fluid flow accompanied by a large drop in pressure. It is desirable to maintain a desired fluid pressure at the openings  44  in order to effectively lubricate and evacuate metal fragments during operation. The insert  34  of this invention provides for the fabrication of smaller openings  44  that maintain the desired pressure of coolant emitted from the face  32 .  
         [0018]     Referring to  FIG. 2  with continued reference to  FIG. 1 , the insert is fabricated separately form the tool body  12 . The example passages  22  are 0.040 inches in diameter to provide the desired pressure of coolant emitted from the face  32 . However other diameters may be used to provide the desired pressure and coolant flow. The angle of the example passages is 8° however; other angles as are required to provide the desired lubrication and cooling of the tool  15  are within the contemplation of this invention.  
         [0019]     Further the openings  44  are spaced a radial distance  50  from the opening  42  for the tool  15 . The radial distance  50  translates to a diameter  52 . The radial distance  50  and diameter  52  are determined to provide a desired coolant spray and pattern from the insert face  32 . The example radial distance is between 0.10 and 0.50 inches from the tool opening  42 . The diameter  52  defined by the circumferentially arranged openings  44  corresponds with the radial distance  50 .  
         [0020]     The insert  34  is fit into the annular channel  22  and is secured therein to provide a fluid tight interface with the body  12 . Installation can include a press fit of the insert  34  into the annular channel  22 . The example insert  34  is installed within the annular channel  22  and then brazed to provide secure the insert therein. Other process for securing the insert  34  within the body  12  is also within the contemplation of this invention.  
         [0021]     Accordingly, the separately fabricated insert  34  provides for the creation of more and smaller openings to maintain the desired pressure of coolant emitted onto the tool.  15 . The resulting smaller and more numerous openings provide the desired pressure at the cutting interface that results in improvements to the final produce along with increasing the durability of the tool  15 .  
         [0022]     The foregoing description is exemplary and not just a material specification. The invention has been described in an illustrative manner, and should be understood that the terminology used is intended to be in the nature of words of description rather than of limitation. Many modifications and variations of the present invention are possible in light of the above teachings. The preferred embodiments of this invention have been disclosed, however, one of ordinary skill in the art would recognize that certain modifications are within the scope of this invention. It is understood that within the scope of the appended claims, the invention may be practiced otherwise than as specifically described. For that reason the following claims should be studied to determine the true scope and content of this invention.