BRIEF DESCRIPTION OF THE DRAWINGS
So that the manner in which the above recited features, advantages and objects of the present invention are attained and can be understood in detail, a more particular description of the invention, briefly summarized above, may be had by reference to the preferred embodiment thereof which is illustrated in the appended drawings, which drawings are incorporated as a part hereof.
It is to be noted however, that the appended drawings illustrate only a typical embodiment of this invention and are therefore not to be considered limiting of its scope, for the invention may admit to other equally effective embodiments.
In the Drawings:
FIG. 1 is a plan view of a machine tool holder such as a boring bar having coolant fluid supply passages therein according to the principles of the present invention, and representing an embodiment of the invention;
FIG. 2 is a side elevational view of the machine tool holder of FIG. 1;
FIG. 3 is a rear elevational view of the machine tool holder of FIG. 1, showing a coolant flow passage longitudinally within the shank of the machine tool holder with the inlet of the coolant flow passage being internally threaded for attachment of the connector of a coolant supply conduit to the machine tool holder;
FIG. 4 is a longitudinal sectional view of the machine tool holder of FIGS. 1-3, showing an internal longitudinal coolant flow passage through the shank and showing a cutter support head and clamp assembly having metal cutting insert being secured in assembly therewith and having a coolant supply passage extending from the internal longitudinal coolant flow passage to a coolant discharge opening directed at the metal cutting insert;
FIG. 5 is an exploded isometric illustration of the machine tool holder of FIGS. 1-5;
FIG. 6 is a plan view of the integral shank and head structure of the machine tool holder of FIGS. 1-5 and showing the internal coolant flow passage thereof in broken line;
FIG. 7 is a side elevational view of the integral shank and head structure of the machine tool holder of FIG. 6, showing coolant flow passage and cutter mounting receptacles in broken line;
FIG. 8 is a rear elevational view of the machine tool holder of FIGS. 6 and 7, showing the coolant entry opening and connector receptacle of the longitudinal flow passage and the cutter insert mounting receptacles in broken line;
FIG. 9 is a sectional view of a clamp member for retaining cutting inserts in assembly with the integral shank and head structure of the machine tool holder of FIGS. 4-6;
FIG. 10 is a bottom view of the clamp member of FIG. 9;
FIG. 11 is a front elevational view of the clamp member of FIGS. 9 and 10;
FIG. 12 is an elevational view of a clamp screw member for retention of the clamp member in secure assembly with the head structure of the machine tool holder and having broken lines showing a longitudinal coolant flow passage extending therethrough;
FIG. 13 is an elevational view of the clamp screw being offset 90° from the position of FIG. 12 and showing a transverse coolant flow passage in communication with the longitudinal coolant flow passage of the shank of the machine tool holder;
FIG. 14 is an elevational view of a seat screw that is employed for retention of a seat member in assembly with the head structure of the machine tool holder;
FIG. 15 is a plan view of the seat screw of FIG. 14; and
FIG. 16 is a partial longitudinal sectional view showing a boring bar representing an alternative embodiment of the invention and having coolant fluid supply passages therein according to the principles of the present invention,
FIG. 17 is an isometric illustration in partially exploded manner, showing a machine tool holder, such as a boring bar, having a coolant fluid distribution system, and representing the preferred embodiment and best mode of the present invention;
FIG. 18 is a plan view of the machine tool holder of FIG. 1;
FIG. 19 is a longitudinal sectional view of the machine tool holder of FIGS. 1 and 2, the section being taken along lines 3-3 of FIG. 2;
FIGS. 20 and 20
a are exploded isometric illustrations showing the fluid distribution and clamping nozzle components of the preferred embodiment and showing that clamping nozzles of different nozzle opening dimension may be employed depending upon the needs of any particular machining operation;
DETAILED DESCRIPTION OF PREFERRED EMBODIMENT
For purposes of simplicity, the present invention is discussed herein particularly with respect to its form as a boring bar for cutting or boring the interior of a rotating work-piece. However, it is to be understood that the present invention has application to a wide range of machine tool holders; thus this specification is to be intended as descriptive of preferred embodiments of the invention and not as restricting the spirit and scope of the invention. Also, while the coolant medium is referred to as a fluid, it is intended that the coolant fluid medium may comprise a liquid or liquid mixture or air or any suitable gaseous medium. Referring now to the drawings and first to FIGS. 1-3 a coolant fluid supplying machine tool holder such as a boring bar is shown generally at 10, having a coolant fluid flow passage therein and representing a preferred embodiment of the present invention. The boring bar 10 comprises an elongate shank 12 having a coolant supplying cutter support head 14 integral therewith. As is evident from the longitudinal sectional view FIG. 4 a coolant fluid flow passage 16 extends longitudinally through the elongate shank 12 to the coolant supplying cutter support head 14 and is provided with an internally threaded receptacle 18. The receptacle 18 is adapted to receive a connector fitting 20 of a fluid supply conduit, such as a flexible coolant fluid supply hose that that is in fluid communication with the discharge passage of a coolant fluid supply pump of a boring machine tool. The coolant fluid flow passage 16 intersects a transverse coolant fluid supply passage 22 that extends through the cutter support head 14 and defines an internally threaded receptacle 24 that is adapted to receive a threaded closure plug member 26. If the internally threaded receptacle 18 is closed by a similar threaded closure plug, the transverse coolant fluid supply passage 22 will serve as an alternative coolant fluid inlet passage, with the connector 20 of a coolant fluid supply conduit being threaded into the internally threaded receptacle 24. This feature provides machine operator personnel with a choice of coolant conduit connection that best suits the machining operation to be conducted.
A portion of the transverse coolant fluid supply passage 22 also serves as a screw passage and is internally threaded as shown at 28 to receive the threaded shank 30 of a clamp screw 32. The clamp screw defines a longitudinal internal coolant fluid flow passage 34, as is evident particularly in FIGS. 4, 12 and 13, which is in fluid communication with the transverse coolant fluid flow passage 22 and thus conducts coolant fluid flow from the passages 16 and 22 to a transverse screw passage 36 which defines at least one and preferably a pair of opposed coolant fluid outlets 38 and 40. The clamp screw 32 defines a screw head 42 having an annular downwardly facing retainer shoulder 44 which is located immediately above an annular seal washer locator surface 46. The screw head 42, defines a screw actuator receptacle 48 which is preferably in the form of a hex or Torx receptacle or may conveniently take the form of a slotted or Phillips receptacle if desired. When threaded to its full extent within the threaded section 28 of the transverse coolant fluid supply passage 22, the annular downwardly facing retainer shoulder 44 is in retaining engagement with a seal washer member 50 and forces the seal washer member into tightly seated and sealed relation with an upper surface 52 of a clamp member 54, which is shown in FIG. 4 and in greatest detail in FIGS. 9-11. During tightening movement of the clamp screw 32 by a hex or Torx wrench the annular seal washer locator surface 46 engages within a central opening 56 of the seal washer member 50 and causes centering of the seal washer member with respect to the transverse coolant fluid supply passage 22. This feature ensures that the seal washer member establishes fluid tight sealing with the surface 52 entirely about a retainer screw opening 58 of the retainer member 54. This feature also ensures against leakage of the coolant fluid medium from the retainer screw opening 58.
As is evident particularly in FIGS. 9 and 10, as well as FIGS. 4 and 5, the clamp member 54 defines a downwardly facing seal receptacle 60 that is preferably concentric with the retainer screw opening and has an annular seal retainer shoulder 62. An annular seal member 64 is at least partially received within the downwardly facing seal receptacle 60 and is forced by the annular seal retainer shoulder 62 into sealed engagement with the clamp member 54 and with an upper surface 66 of the boring bar head structure 14. The annular seal member 64 may be composed of any suitable resilient or elastomeric sealing material or it may be composed of any metal or non-metal material that is capable of establishing sealing between the clamp member and the head structure of the boring bar when the clamp screw 32 is tightened. The clamp member 54 defines an internal slot 68 which is sealed at its upper end by the seal washer member 50 and is in fluid communication with an annular groove or recess 70 within which the coolant fluid outlet openings 38 and 40 are located. The clamp member also defines a coolant discharge passage 72 extending from the internal slot 68 to a discharge opening 74. If desired, the clamp member may define a plurality of coolant discharge passages having a plurality of coolant discharge openings if additional or more efficient cooling can be achieved. The coolant fluid discharge passage 72 and the discharge opening 74 are oriented and located to project a jet of coolant fluid strategically onto a metal cutting insert 76 so that the cutting edge of the metal cutting insert and the metal being cut receive continuous cooling. The service life of the metal cutting insert and the efficiency of metal cutting is enhanced when the cutting temperature is controlled by an efficient and accurately directed and controlled flow of coolant immediately at the site of the metal cutting operation.
The clamp member 54 is located and stabilized in part by a downwardly extending locator projection 78 which is of elongate configuration and is defined by oppositely inclined downwardly converging side cam surfaces 80 and 82 that intersect at an elongate rather sharp ridge 84. The downwardly extending locator projection 78 also defines oppositely inclined downwardly converging end cam surfaces 86 and 88 that intersect the ridge 84 and define the ends of the ridge. The downwardly extending locator projection 78 is received by a clamp location and stabilizing receptacle 90 having a corresponding downwardly converging tapered configuration and permits the downwardly extending locator projection 78 to establish substantial surface to surface locking and stabilizing engagement with the head structure 14 of the boring bar as indicated particularly in FIG. 4. This feature prevents movement of the clamp member 54 even when subjected to the forces of heavy or rough metal cutting by the replaceable metal cutting insert 76, especially during the initial stage of machining.
The clamp member 54 also defines a retainer nose portion 92 on which is integrally formed a cutter insert locator projection 94 of generally cylindrical configuration. The cutter insert locator projection 94 is received within a central opening 96 of the cutter insert member 76 for precision location of the replaceable cutter insert member 76 on the coolant supplying cutter support head 14. When seated to its full extent the lower end 98 of the cutter insert locator projection 94 is located in close fitting relation within the central opening 96 of the cutter insert to ensure against shifting of the cutter insert even under the influence of the significant forces of rough metal cutting. The central opening 96 is also of generally cylindrical configuration and thus ensures against any lateral as well as vertical movement of the cutter element relative to the clamp member 54.
The head structure 14 of the boring bar 10 is drilled or otherwise formed to define a passage 102, as shown in FIG. 4, which includes an internally threaded section 104 that receives the threaded shank 106 of a seat screw 108, which is shown in greater detail in FIGS. 14 and 15. The seat screw 108 defines a screw actuator receptacle 110 which may be of hex or Torx form or may have any other screw actuator receptacle form as desired. The seat screw 108 also defines a screw head 112 having a tapered shoulder surface 114 that establishes locating and stabilizing engagement within a central correspondingly tapered annular internal surface 116 that defines at least a portion of a opening 117 of a seat member 118. The seat screw is tightened to force the seat member 118 into supported engagement with a seat support shoulder 120 of the head structure 14. The seat support shoulder 120 is oriented at a desired angle, with respect to the center-line of the boring bar shank 12, to achieve desired orientation of the seat member 118 and the metal cutting insert 76 for optimum metal cutting and extended service life of the metal cutting insert.
Generally planar seat locator and stabilizer surfaces 122 and 124 are defined by the head structure 14 and are oriented for precision location and stabilization of respective side surfaces 126 and 128 of the generally rectangular seat member 118. When the seat member is secured in place by the seat screw 108, the planar seat locator and stabilizer surfaces 122 and 124 prevent the seat member from being rotated or otherwise moved by the forces encountered during machining. Precision location of the seat member 118 on the seat and cutter support shoulder surface 120 is controlled by interaction of the tapered shoulder surface 114 of the seat screw 108 with the correspondingly tapered internal surface that is defined within the seat member 118. Generally planar cutter insert locator surfaces 130 and 132 are also defined by the head structure 14 and are oriented in angular relation for precision location and support with corresponding side surfaces or edges 134 and 136 of the generally rectangular cutter insert 76. Support ledges 138 and 140 are defined at the juncture of the seat locator and stabilizer surfaces 122 and 124 and the cutter insert locator surfaces 130 and 132 to provide support for respective lower edges of the metal cutting insert 76. A corner relief recess 142 is also defined in the head structure 14 and is defined in part by curved or arcuate corner relief recess surfaces 144 and 146 at the juncture of the seat and cutter insert support and stabilization surfaces. The corner relief recess 142 ensures that a corner of the seat member 118 and metal cutting insert 76, are free from contact with the locating and stabilizing surfaces of the head structure 14. The corner relief recess 142 is also defined in part by a curved or arcuate ledge 148 which exists due to the differing dimensions of the locating and stabilizing surfaces of the head structure 14.
With reference to FIGS. 6-8, it should be borne in mind that the transverse coolant fluid supply passage 22 may be drilled or otherwise formed so that it does not extend completely through the head structure 14 of the machine tool holder or boring bar 10. In such case, the passage 22 merely extends a sufficient distance to establish fluid flow conducting communication with the longitudinal coolant fluid flow passage 16 which is evident particularly as shown in broken line in FIG. 7. The coolant fluid supply passages are arranged as shown in FIG. 4 if it is intended to provide the user with the capability of selectively connecting a coolant fluid supply conduit to the internally threaded receptacle 18 of the shank 12 or to the internally threaded receptacle 24 of the head structure 14. In either case, a threaded plug member is employed as a closure for the unused internally threaded receptacle 18 or 24.
As shown in the embodiment of FIG. 4 coolant fluid flow from the transverse coolant fluid supply passage 22 to the coolant fluid discharge passage 72 of the clamp member 54 occurs via a longitudinal coolant fluid flow passage 34 of the clamp screw 32. It should be borne in mind that coolant fluid flow may also or alternatively occur externally of the clamp screw. As shown in the alternative embodiment of FIG. 16, the screw passage is enlarged to provide an annular clearance externally of the clamp screw which serves as an annular flow passage for coolant flow. In this case, the clamp screw will not be provided with an internal longitudinal flow passage. Like components of FIG. 16, as compared with FIG. 4, are shown by like reference numerals.
As shown in FIG. 16, the head structure 14 is machined to define a clamp screw passage section 150 having a dimension exceeding the external diameter of the shank 152 of a clamp screw 154, thus establishing an annular flow passage 156 that surrounds the shank of the clamp screw. This annular flow passage intersects the longitudinal coolant fluid flow passage 16 of the boring bar shank 12 and thus permits the flow of coolant fluid from the shank of the boring bar, through the head structure to the flow passages 72 of the clamp member 54. Unlike the clamp screw 32 of FIG. 4, the clamp screw 154 has a shank 152 that does not define an internal longitudinal flow passage. Rather, the flow passage 156 is defined by an annular space that is cooperatively defined by the external surface of the clamp screw shank 152 and the enlarged internal surface of the clamp screw passage section 150. The shank 152 of the clamp screw also defines an annular space with the internal surface of the passage 58 through the clamp member, which annular space is an extension or continuation of the annular flow passage 156. The upper end of this annular space is closed and sealed by the seal washer 50. The annular seal member 64 establishes sealing of the annular flow passage at the lower portion of the clamp member 54 as explained above. The function of the embodiment of FIGS. 4 and 16 are essentially the same, with the exception that fluid flow along the shank of the clamp screw differs. In each case, the flow of coolant fluid from the longitudinal flow passage of the shank 12 of the boring bar 10 is transitioned through the head structure 14 to the clamp member 54 and is then conducted through the clamp member to one or more discharge openings 72 that are located and oriented to direct the flow of coolant fluid directly onto the cutter insert 76 to the immediate region of contact of the cutter insert within the rotating work-piece.
Referring now to FIGS. 17-20 a preferred embodiment and best mode of the present invention is represented by a machine tool holder assembly shown generally at 160 which may conveniently take the form of a boring bar or any other type of support for a replaceable metal cutter element. The machine tool holder, especially when in the form of a boring bar, includes an elongate tool shank 162 which, as shown in FIG. 19, defines an internal longitudinal coolant fluid supply passage 164 through which coolant fluid is conducted to the head portion 166 of the tool. A fluid supply fitting 168, such as the 90° swivel fitting of FIGS. 18 and 19 is threaded into one end of the tool shank 162 and provides for connection to a coolant supply line, not shown. Within the head portion 166 of the machine tool holder is located a coolant distribution passage 170 which is in fluid communication with the internal longitudinal coolant fluid supply passage 164. The passage 170 is disposed in angulated intersecting relation with the passage 164 thus permit its outlet end to be properly oriented for flushing away metal chips or cuttings that occur during machining operations. A chip flushing nozzle 172 is threaded into an internally threaded outlet section of the passage 170 and provides a nozzle outlet 174 that is of proper dimension to develop a jet 176 of coolant fluid that is oriented to blast away metal chips and to thus minimize the potential for any undesirable accumulation of metal chips that might otherwise interfere with or otherwise compromise the efficiency of the metal cutting operation.
The head portion 166 of the tool holder is machined to define an internally threaded bore 178 which receives a retainer screw 180 and secures a cutter insert seat member 182 firmly to a seat surface 184 that is defined by the head portion 166 of the machine tool holder 160. The retainer screw is provided with a tapered head that is received within a screw head receptacle 188 of the seat member 182. When the retainer screw 180 is threaded into the threaded bore to its full extent, the upper end of the retainer screw is recessed below the level of the upper surface of the cutter insert seat member 182.
The head portion 166 of the tool holder is also machined to define an internally threaded bore 190 that intersects the coolant distribution passage 170 and receives a threaded retainer or clamp screw 192 that secures a combination nozzle and clamp member 194 to the head portion 166. The combination nozzle and clamp member 194 bears against an upper surface of a replaceable cutter element 196 and serves to retain the cutter element firmly seated on the seat member 182 and firmly secured within a cutter receptacle 198 of the tool head portion 166. The clamp or retainer screw 192 defines an axial flow passage 200, shown in FIGS. 19 and 20, that is in fluid communication with the coolant distribution passage 170 and also defines a reduced diameter annulus 202 and a flow port 204 establishing communication of the annulus with the axial passage 200. Leakage of coolant fluid at the retainer or clamp screw is prevented by a metal to metal seal that is developed by the flat annular downwardly facing surface 203 of the screw head which engages a corresponding annular flat shoulder surface 205 that is located within the threaded receptacle 208. An annular resilient seal member 207 is positioned around the threaded shank of the retainer bolt and is compressed within an annular seal receptacle that is defined by the lower portion of the nozzle and clamp structure immediately about the screw hole.
The combination nozzle and clamp member 194 defines one or more internal flow passages 206 that are in communication with a threaded receptacle 208 within which the annulus 202 is received. The annulus communicates coolant fluid from the axial flow passage 200 of the retainer bolt to the passage or passages 206 and the passages direct the flowing coolant medium to a discharge or jet opening 210 from which a jet or jets of coolant fluid is directed to the cutting interface which is located only a few millimeters distant. As is indicated in FIG. 20a, combination nozzle and clamp members will be provided with discharge openings 210a of differing dimension, depending on the volume of coolant fluid that is intended to be projected at the cutting interface. The jet or jets of coolant fluid are projected immediately to the typically small rounded cutting edge which is located at each of the typically two, three or four corners of a replaceable metal cutting insert. Thus, a cutter insert is typically loosened, rotated to another of its two, three or four positions when one of its cutting edges becomes dull. This is repeated until each of the cutting edges has been used to the point that cutting efficiency has become degraded, after which the cutter insert element is typically discarded and replaced by a new cutter insert.
At the juncture of the head portion 166 with the shank 162 there is machined a depression 212 having an inclined surface 213. The rear portion of the combination nozzle and clamp member 194 defines a depending orienting and locking member 214 which fits within the depression 212 with a tapered surface 216 disposed in orienting engagement with the inclined surface of the depression. This feature controls orientation of the nozzle member 194 so that the discharge opening 210 is precisely oriented. Orientation of the nozzle member and prevention of its rotation during machining operations is further enhanced by a locking pin 211 which is received within a matching recess defined by the rear portion of the nozzle member and with one end of the locking pin being received within a vertically oriented hole of the head portion of the tool holder. Further, the inclined and tapered surfaces interact during tightening of the retainer bolt 180 and cause the development of a generally horizontal pulling force which urges the cutter insert in a rearward direction thus ensuring that the cutter insert is seated firmly against the angulated support surfaces or walls 217 and 219 that define the cutting insert receptacle of the head portion of the tool holder. Also, the geometry of the nozzle and clamp member and the head portion of the machine tool holder cause the forward end of the nozzle member 194 to apply a downwardly directed clamping force to a cutter insert 196, thus positively retaining the cutter insert in a manner preventing upward or downward movement or yielding during metal cutting operations.
At the forward end of the nozzle member 194 is located a depending locking member 218 which is received in close fitting relation within a circular retainer opening 220 which is located at the center of a cutter insert. The locking member provides mechanical stabilization for the cutter insert during machining operations to prevent any degree of rotation of the cutter insert within its seat while the clamping force of the nozzle structure efficiently secures the cutter insert from upward or downward movement.
In view of the foregoing it is evident that the present invention is one well adapted to attain all of the objects and features hereinabove set forth, together with other objects and features which are inherent in the apparatus disclosed herein.
As will be readily apparent to those skilled in the art, the present invention may easily be produced in other specific forms without departing from its spirit or essential characteristics. The present embodiment is, therefore, to be considered as merely illustrative and not restrictive, the scope of the invention being indicated by the claims rather than the foregoing description, and all changes which come within the meaning and range of equivalence of the claims are therefore intended to be embraced therein.
Patent Application
20070286689
