Abstract:
A tool is disclosed, including an interchangeable cutting member and an adapter to which said interchangeable cutting member is adapted to be replaceably mounted. The interchangeable cutting member comprises a substantially ball-shaped body with a cutting surface, within which a female screw-thread is provided. The adapter is provided having a male screw-thread portion configured and arranged for screw-engagement in the female screw-thread. A coolant or lubricant fluid passage is provided in the interchangeable cutting member. The coolant or lubricant fluid passage ends at the cutting surface of the ball-shaped member.

Description:
TECHNICAL FIELD 
       [0001]    The subject matter disclosed herein relates to cutting tools for metal cutting machines. More specifically, the present subject matter disclosed herein relates to cutting tools comprising an adapter and an interchangeable cutting portion connectable to the adapter for support on a machine tool or a machining center. 
       BACKGROUND 
       [0002]    Several machining processes require the use of interchangeable ball-shaped cutting tools supported by a holder for connection with a rotating mandrel of machine tools.  FIG. 1  illustrates a side view of an interchangeable tool according to the current art and  FIG. 2  illustrates the tool of  FIG. 1  connected to a mandrel of a machine tool with a tool holder therebetween. The tool  101  comprises a cutting portion  103 , which is generally ball-shaped, i.e. having a cutting surface with at least a portion having a substantially spherical shape. The cutting surface of the cutting portion is provided with cutting edges  105  designed for machining of a workpiece by chip-removal, for example for machining an impeller of a turbomachine. The cutting portion  103  is monolithically formed with a spigot  107  having a threaded portion  109  for screw connection to a tool holder  111  shown in  FIG. 2 . The tool  101  is screw-connected to the tool holder  111  and the latter is mounted on a rotating mandrel  113 , for example the mandrel of a working head of a machine tool or machine center. 
         [0003]    The tool  101  according to the current art is expensive to manufacture. Moreover, delivery of a coolant or lubrication fluid in the working area of the tool  101  is difficult, especially during machining of complex workpieces, such as impeller vanes. 
         [0004]    There is therefore a need for a cutting tool, which at least partly alleviates one or more of the drawbacks of known cutting tools. 
       SUMMARY OF THE INVENTION 
       [0005]    According to some embodiments, a tool is provided, which comprises an interchangeable cutting member and an adapter to which the interchangeable cutting member is adapted to be replaceably mounted. The interchangeable cutting member comprises a substantially ball-shaped body with a cutting surface, within which a female screw-thread is provided. The adapter can be provided with a male screw-thread portion configured and arranged for screw-engagement in the female screw-thread. Moreover, at least one coolant or lubricant fluid passage can be provided in the interchangeable cutting member. The coolant or lubricant fluid passage ends at the cutting surface of the ball-shaped member. A coolant or lubricant fluid delivery duct is provided in the adapter, in fluid communication with the coolant or lubricant fluid passage when the interchangeable cutting member and the adapter are screwed together. Moreover, in an embodiment, the adapter can be provided with a first conical surface and the interchangeable cutting member is provided with a second conical surface configured and arranged for mutually centering the adapter and the interchangeable cutting member, when the adapter and the interchangeable cutting member are screwed together. 
         [0006]    The adapter can further be provided with a first axial abutment surface and the interchangeable cutting member can be provided with a second axial abutment surface. The first axial abutment surface and the second axial abutment surface are mutually engageable for axially positioning the interchangeable cutting member and the adapter one with respect to the other when the interchangeable cutting member and the adapter are screwed together. According to some embodiments, the first axial abutment surface and the second axial abutment surface are orthogonal to a rotation axis of the tool. 
         [0007]    According to some embodiments of the subject matter disclosed herein, the first conical surface on the adapter is concave and the male screw-thread portion of the adapter is partly arranged in a cavity formed by the concave first conical surface and projects therefrom. Moreover, the second conical surface on the interchangeable cutting member can be a convex surface formed on a projection of the interchangeable cutting member, the female screw-thread extending in the projection, the projection being configured for engaging in the cavity formed by the concave first conical surface when the interchangeable cutting member and the adapter are screwed together. 
         [0008]    According to a further aspect, the subject matter disclosed herein concerns a tool assembly comprising a tool as described above and a tool holder, the adapter of the tool comprising a first connector member co-acting with a second connector member provided on the tool holder. 
         [0009]    Features and embodiments are disclosed here below and are further set forth in the appended claims, which form an integral part of the present description. The above brief description sets forth features of the various embodiments of the present invention in order that the detailed description that follows may be better understood and in order that the present contributions to the art may be better appreciated. There are, of course, other features of the invention that will be described hereinafter and which will be set forth in the appended claims. In this respect, before explaining several embodiments of the invention in details, it is understood that the various embodiments of the invention are not limited in their application to the details of the construction and to the arrangements of the components set forth in the following description or illustrated in the drawings. The invention is capable of other embodiments and of being practiced and carried out in various ways. Also, it is to be understood that the phraseology and terminology employed herein are for the purpose of description and should not be regarded as limiting. 
         [0010]    As such, those skilled in the art will appreciate that the conception, upon which the disclosure is based, may readily be utilized as a basis for designing other structures, methods, and/or systems for carrying out the several purposes of the present invention. It is important, therefore, that the claims be regarded as including such equivalent constructions insofar as they do not depart from the spirit and scope of the present invention. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0011]    A more complete appreciation of the disclosed embodiments of the invention and many of the attendant advantages thereof will be readily obtained as the same becomes better understood by reference to the following detailed description when considered in connection with the accompanying drawings, wherein: 
           [0012]      FIG. 1  illustrates a side view of a cutting tool of the current art; 
           [0013]      FIG. 2  illustrates the use of the cutting tool of  FIG. 1  on an electro-mandrel of a machine tool; 
           [0014]      FIG. 3  illustrates a side view and a partial section of an adapter of a tool according to the present disclosure in one embodiment; 
           [0015]      FIGS. 4 and 5  illustrate side and partial sectional views according to lines IV-IV and V-V of  FIG. 6 ; 
           [0016]      FIG. 6  illustrates a front view according to line VI-VI of  FIG. 4 ; 
           [0017]      FIG. 7  illustrates a side and partial sectional view of the tool according to  FIGS. 3 to 6  in an assembled condition; 
           [0018]      FIGS. 8 and 9  illustrate side views oriented at 90° of the tools of  FIGS. 3 to 7 ; 
           [0019]      FIG. 10  illustrates a side and partial sectional view of an adapter of a tool according to the disclosure in a second embodiment; 
           [0020]      FIG. 11  illustrates the cutting member of the tool according to the second embodiment; and 
           [0021]      FIG. 12  illustrates a side and partial sectional view of the tool of  FIGS. 10 and 11  with the cutting member attached to the adapter. 
       
    
    
     DETAILED DESCRIPTION 
       [0022]    The following detailed description of the exemplary embodiments refers to the accompanying drawings. The same reference numbers in different drawings identify the same or similar elements. Additionally, the drawings are not necessarily drawn to scale. Also, the following detailed description does not limit the invention. Instead, the scope of the invention is defined by the appended claims. 
         [0023]    Reference throughout the specification to “one embodiment” or “an embodiment” or “some embodiments” means that the particular feature, structure or characteristic described in connection with an embodiment is included in at least one embodiment of the subject matter disclosed. Thus, the appearance of the phrase “in one embodiment” or “in an embodiment” or “in some embodiments” in various places throughout the specification is not necessarily referring to the same embodiment(s). Further, the particular features, structures or characteristics may be combined in any suitable manner in one or more embodiments. 
         [0024]    A first embodiment of a tool according to the present disclosure is illustrated in  FIGS. 3 to 9 . The tool is labeled  1  as a whole. In some embodiments the tool  1  is comprised of an adapter  3  and a cutting member  5 . In some embodiments the cutting member  5  and the adapter  3  are connected to one another by means of screw threads as will be described in greater detail here below. 
         [0025]    The cutting member  5  comprises an outer surface  5 A provided with cutting edges, schematically shown at  5 E only in  FIG. 7 . 
         [0026]    The outer cutting surface  5 A of the cutting member  5  has a broadly spherical shape in this embodiment. 
         [0027]    The cutting member  5  comprises a projection  7  extending from a flat annular surface  9  provided on the cutting member  5 . The annular surface  9  is orthogonal to an axis A-A of the cutting member  5 . 
         [0028]    In some embodiments the projection  7  has a cavity formed by a threaded hole  11 , the inner surface whereof is provided with a female screw-thread  12 . 
         [0029]    In some embodiments a coolant and/or lubricant fluid distribution duct  13  is provided in the interior of the cutting member  5 . The coolant and/or lubricant liquid distribution duct  13  is more particularly parallel to and coaxial with axis A-A of the cutting member  5 , the axis corresponding to the rotation axis of the tool. In some embodiments the coolant and/or lubricant liquid distribution duct  13  extends from the bottom of the threaded hole  11  and ends with a coolant and/or lubricant fluid passage  15  leading to the outer surface  5 A of the cutting member  5 . 
         [0030]    In some embodiments auxiliary or additional coolant and/or lubricant fluid passages are provided in the body of the cutting member  5 . In the embodiment illustrated in  FIGS. 1 to 9  four such additional coolant and/or lubricant fluid passages  17  are provided. The coolant and/or lubricant fluid passages  17  extend from the central fluid distribution duct  13  towards the surface  5 A of the cutting member  5 . 
         [0031]    In some embodiments the passages  17  are distributed at regular angular intervals around axis A-A and are oriented such as to form an angle a with the axis A-A of the tool which is different from 90°. In particular the inclination of the passages  17  is more particularly such that the passages  17  end at the outer surface  5 A of the cutting member  5  in the hemispherical portion of the cutting surface  5 A opposite projection  7 . 
         [0032]    In some embodiments, the adapter  3  comprises a central body  21  from which a threaded spigot  23  extends. The threaded spigot  23  is configured for connection with a holder, for example a holder  111  as shown in  FIG. 2 . 
         [0033]    In an embodiment, on the end of the central body  21  to the spigot  23 , the adapter  3  is provided with a planar front surface  25 . The front surface  25  can be annular and surrounding an inner cavity  27  extending inside the central body  21 . 
         [0034]    In some embodiments the inner cavity  27  has an inner side surface  29  having a conical frustum-shaped form and ends with a bottom  31 . The inclination of the conical frustum-shaped surface  29  is substantially the same as the inclination of an external conical frustum-shaped surface  32  provided on the outside of the projection  7 . 
         [0035]    From the bottom  31  of the inner cavity  27  of the adapter  3  a male screw-thread portion  33  extends coaxial with the conical frustum-shaped surface  29  and projects beyond the planar annular surface  25 . 
         [0036]    As can be better appreciated from  FIG. 7 , when the cutting member  5  is connected with the adapter  3 , the male screw-thread portion  33  of the adapter  3  is screw-engaged with the female screw-thread  12  provided on the inner surface of cavity  11  formed in the cutting member  5  so as to provide connection between the adapter  3  and the cutting member  5 . 
         [0037]    The cutting member  5  and the adapter  3  are screwed together until the annular planar surface  25  abuts against the annular planar surface  9  provided on the cutting member  5 , the surfaces  25  and  9  providing first and second abutting surfaces respectively, which define the mutual axial position of the cutting member  5  with respect to the adapter  3  when the two components of the tool  1  are connected to one another. 
         [0038]    The concave conical frustum-shaped surface  29  co-acts with the convex conical frustum-shaped surface  32  to provide a centering and a supporting action during screw-connection of the adapter  3  to the cutting member  5 . 
         [0039]    The depth of the inner cavity  27  and the extension of the projection  7 , as well as the length of the male screw-thread portion  33  and the depth of the cavity  11  are chosen so that in the assembled condition ( FIG. 7 ) the cutting member  25  and the adapter  3  are in mutual contact only along the two conical frustum-shaped surfaces  29  and  32  and at the mutually meshing screw-threads provided on the male screw-thread portion  33  and in the cavity  11 . 
         [0040]    In some embodiments the adapter  3  is provided with a coolant and/or lubricant delivered duct  35 . In some embodiments the coolant and/or lubricant fluid delivery duct  35  is coaxial with the adapter  3 , i.e. the axis of the duct  35  coincides with the axis A-A of the adapter  3  and correspondingly with the axis A-A of the cutting member  5  and of the assembled tool  1  (see  FIGS. 7 ,  8  and  9 ). 
         [0041]    The coolant and/or lubricant delivery duct  35  extends from one end of the adapter  3  to the opposite end thereof. More specifically, the coolant and/or lubricant fluid delivery duct  35  extend from the terminal end surface of the spigot  23  to the front surface of the male screw-thread portion  33 . 
         [0042]    When the cutting member  5  and the adapter  3  are screw connected to one another ( FIG. 7 ) a distribution system for delivering the coolant or lubricant fluid is established, which extends from the spigot  23  to the cutting surface  5 A of the cutting member  5 . A coolant and/or lubricant fluid can thus be dispensed through the holder  111  (which can similarly be provided with a through passage), across the adapter  3  and the cutting member  5  and finally delivered exactly there where it is needed, namely in the area of contact between the cutting surface  5 A and a work-piece being machine with the tool  1 . Delivery of the coolant and/or lubricant fluid is thus made easier in all those situations where delivery of the coolant and/or lubricant fluid through an external nozzle would be difficult or critical, for example inside a vane of an impeller. 
         [0043]    A second embodiment of the tool according to the present disclosure is shown in  FIGS. 10 to 12 . The same reference numbers are used to designate similar, identical or equivalent portions, components, or elements as shown in  FIGS. 3 to 9 . 
         [0044]    In the embodiment of  FIGS. 10 to 12  the adapter  3  is again provided with a threaded spigot  23  and a coolant and/or lubricant fluid delivery duct  35  extending through the entire axial length of the adapter  3 . 
         [0045]    On the side of the central body  21  opposite the spigot  23 , the adapter  3  is provided with an intermediate portion  41  forming an outer conical frustum-shaped surface  43 . In an embodiment, the larger base of the frustum-shaped surface  43  is surrounded by a planar annular surface  45 , which is coaxial therewith and with the spigot  23  and the body  21  of the adapter  3 . From the smaller base of the conical frustum-shaped portion  41  a male screw thread portion labeled  33  projects from the adapter  3 . 
         [0046]    The cutting member  5  comprises an inner cavity  51 , extending co-axially with the cutting member  5 . The cavity  51  has a first portion or section having a conical frustum-shaped inner side surface  53 . The conical frustum-shaped surface  53  has substantially the same shape as the conical frustum-shaped convex surface  43  to form a pair of supporting and guiding surfaces. 
         [0047]    The cavity  51  extends further within the body of the cutting member  5  to form a threaded hole  55 , wherein a female screw-thread  57  is provided. A coolant and/or lubricant fluid passage  15  extends from the bottom of the hole  55  towards the surface of the cutting member  5 . 
         [0048]      FIG. 12  illustrates the tool  1  of the second embodiment with the cutting member  5  screwed on the adapter  3 . The two conical frustum-shaped surfaces  32  and  53  co-act with one another providing a guiding and centering action between the two components  3  and  5  of the tool  1 . The male screw-thread portion  33  is screw-engaged in the threaded hole  55 , the male screw-thread engaging the female screw-thread  57 . The annular planar surface  45  forms an abutment co-acting with a planer annular surface  59  provided on the cutting member  5  and surrounding cavity  51 . 
         [0049]    The depth of the cavity  51 , of the hole  55 , as well as the axial length of the conical portion  41  and of the male screw-thread portion  33  of the adapter  3  are chosen so that in the assembled condition ( FIG. 12 ) the two components  3  and  5  abut one against the other only at surfaces  45  and  59 . 
         [0050]    Coolant and/or lubricant fluid is delivered through the duct  35  from a holder  111  to the passage  15 . 
         [0051]    In some embodiments additional coolant and/or lubricant fluid passages  61  can be provided. In some embodiments, such additional passages  6 l can be provided in the adapter  3 , for example in the body  21  thereof. The inclination of these additional passages  61  is such that a jet of coolant and/or lubricant fluid is directed towards and around the cutting member  5  for cooling and lubricating purposes as well as for removing of chips from the machining area. 
         [0052]    While the disclosed embodiments of the subject matter described herein have been shown in the drawings and fully described above with particularity and detail in connection with several exemplary embodiments, it will be apparent to those of ordinary skill in the art that many modifications, changes, and omissions are possible without materially departing from the novel teachings, the principles and concepts set forth herein, and advantages of the subject matter recited in the appended claims. Hence, the proper scope of the disclosed innovations should be determined only by the broadest interpretation of the appended claims so as to encompass all such modifications, changes, and omissions. In addition, the order or sequence of any process or method steps may be varied or re-sequenced according to alternative embodiments.