Abstract:
A cutting tool for use with a lathe includes an elongated body member having a generally rectangular cross section dimensioned and configured for cooperation with an associated tool post. The elongated body member has a head end having a step shaped surface thereon on which is disposed a plurality of generally radially extending ribs disposed at equal angular increments. The ribs extend through an arc of 360 degrees. A first head assembly has a lower extremity which includes a surface having a plurality of generally radially extending ribs disposed at equal angular increments thereabout. These ribs are uniformly spaced and dimensioned and configured for cooperation with the ribs of the body portion. The ribs of the head assembly and the body portion have the same angular spacing therebetween. The head assembly includes discrete means for holding a cutter insert and means for holding the head assembly on the body portion.

Description:
BACKGROUND OF THE INVENTION 
     The invention relates to machine tools and particularly to universal tool assemblies for use with lathes. The prior art includes various tool holding apparatus for use with lathes. A common construction is a tool post having a vertically elongated slot which cooperates with a tool which has a replaceable tip or cutting insert. 
     The prior art also includes the structure disclosed in the applicant&#39;s Swedish Pat. No. 332,557. The apparatus disclosed therein provides a substantial improvement over the structures known previously. However, this apparatus has less adjustment range than is desirable and in addition one screw, which extends from the top of the assembly, holds the entire assembly together. This has the result that when the single screw is loosened the entire assembly comes apart and accordingly the precise angular positioning of the apparatus must again be reset in a time consuming manner. 
     It is an object of the invention to provide apparatus which is flexible and adaptable to a variety of operating conditions and requirements. 
     It is another object of the invention to provide apparatus which allows cutting at each degree throughout the entire 360 degree range of possible cutting positions. 
     It is another object of the invention to enable the removal and replacement of cutting inserts with accurate and rapid repositioning of the tool after replacement of the insert. 
     Still another object of the invention is to provide apparatus which eliminates the requirement for numerous extra accessories and attachments in order to provide the wide range of tool positions that may be attained with the apparatus in accordance with the invention. 
     Yet another object of the invention is to provide apparatus which will produce a smooth machined finish which is superior to that which may be obtained with many other tool assemblies. 
     Yet another object of the invention is to provide apparatus which is simple and inexpensive to manufacture as compared to alternative types of equipment which would achieve the same results. 
     SUMMARY OF THE INVENTION 
     The foregoing objects and other objects and advantages which shall become apparent from the detailed description of the preferred embodiment are attained in a cutting tool for use with a lathe which includes an elongated body member having a generally rectangular cross section dimensioned and configured for cooperation with an associated tool post. The elongated body member has a head end having a step shaped surface thereon on which are disposed a plurality of generally radially extending ribs disposed at equal angular increments. The ribs extend through an arc 360 degrees. A first head assembly has a lower extremity which includes a surface having a plurality of generally radially extending ribs disposed at equal angular increments thereabout. The ribs of The assembly are uniformly spaced and are dimensioned and configured for cooperation with the ribs of the body portion. The ribs of the head assembly and the body portion have the same angular spacing therebetween. The head assembly includes discrete means for holding a cutter insert and means for holding the head assembly to the body portion. 
     The apparatus may further include a reference mark on the body portion and a plurality of discrete spaced reference marks disposed on the head assembly to permit precise alignment therebetween in a plurality of predetermined positions. The apparatus may further include at least one additional head assembly having a lower extemity which has a surface having a plurality of generally radially extending ribs disposed at equal angular increments thereabout. The ribs may be uniformly spaced and dimensioned and configured for cooperation with the ribs of the body portion. The apparatus may have discrete means for holding an associated cutter assembly and means for holding the head assembly in engagement with the body portion. The second head assembly may have means for holding an associated cutting insert at an angular orientation, with respect to the ribs, which is different from the angular orientation at which the associated cutter insert is held by the first head assembly. The difference in angular orientation of the associated cutter, with respect to the ribs, in the second head assembly and the first head assembly may be equal to the angular increment between the teeth in the first and second head assemblies and the base portion. This angular increment between the teeth or ribs may be 6 degrees. The head assemblies may be identified with indicia corresponding to an angle with which the associated cutting insert is disposed when the mark adjacent to the indicia is aligned with an index mark on the body portion. 
    
    
     BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWING 
     FIG. 1 is a plan view of the assembled apparatus in accordance with the invention; 
     FIG. 2 is a side elevational view of the head end of the body portion of the cutting tool apparatus illustrated in FIG. 1; 
     FIG. 3 is a sectional view along the line 3--3 of FIG. 2; 
     FIG. 4 is plan view of the head end body portion of the cutting tool illustrated in FIG. 1; 
     FIGS. 5 and 6 are bottom views respectively of first and second left handed cutter holders or head assemblies which cooperate with the body portion illustrated in FIGS. 1-4; 
     FIGS. 7 and 8 are bottom views respectively of first and second cutter holders or right handed head assemblies which cooperate with the body portions illustrated in FIGS. 1-4; and 
     FIG. 9 is an elevational view of a head assembly illustrated in FIG. 5. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Referring now to FIG. 1 there is illustrated a cutting tool 10 which includes an elongated generally rectangular cross section body portion 12 which is intended for cooperation with a tool post (not shown) of a lathe type apparatus (not shown). Such apparatus may include screw machines and other apparatus which rotate the work piece. 
     The body portion 12 includes a head portion 14 which is further illustrated in FIGS. 2-4. 
     The head portion 14 includes a generally circular step 16 intended for cooperation, at any one time, with one of the head assemblies illustrated in FIGS. 5-8. 
     The step 16 is provided with a plurality of radially extending ribs or teeth 18 which are disposed at equal angular increments throughout the 360 degree extent thereof. 
     The head portion 14 is provided with a first circular recess 20 and a second circular recess 22. The second circular recess 22 is smaller in diameter than the circular recess 20. A central bore 24 extends through the head portion 14 and is axially aligned with both the recess 20 and the recess 22. A recess 26 extends around the lower axial extremity of the central bore 24. In some forms of the invention the radial extending ribs 18 may be manufactured as part of a discrete ring 28 which may have two integral keys 30 (one shown) which cooperate with key ways 32 in the body portion 12 to prevent relative angular rotation between the head portion 14 and the ring 28. An arcuate recess 34 is provided for accommodating the cutter holder or head assembly 40. An index mark 36 is disposed on the body portion 12 as a reference mark for precise positioning of the cutter holder 40 or other alternative cutter holders to be described hereafter. 
     In FIGS. 5-6 there are illustrated first and second cutter holders or head assemblies 40 and 40A. The lower extremity of each of the cutter holders 40 and 40A are provided with a plurality of ribs or teeth 42 which are disposed at equal angular increments and are substantially identical in contour and spacing so that they will cooperate easily with the ribs or teeth 18 disposed on the step 16. The ribs 42 extend throughout the 360 degree extent of the lower extremity of the cutter holders 40 and 40A. In one preferred form of the apparatus in accordance with the invention the interval between successive teeth 42, as well as between successive teeth 18, is 6 degrees. In other forms of the invention other spacings may be provided. For example, a spacing of 3 degrees may also conveniently be utilized. 
     Referring now to FIGS. 7 and 8 there are shown first and second cutter holders or head assemblies 43, 43A which are each provided with radially extending ribs or teeth 42 as are the head assemblies 40, 40A. Each of the head assemblies 40, 40A, 43, 43A is provided with a locating annular boss 45 which engages the recess 30 of the head portion 14. As best seen in FIGS. 1 and 9 each cutter holder 40, 40A, 43, 43A is provided with a cutting plate or insert 44 which is held against the step 47 by means of a retainer 46 which is secured to the step 16 by a set screw 50 having a hexagonal drive surface. The set screw 50 ordinarily will have a head having a lower surface (not shown) which is conical to precisely position the retainer 46. 
     The assemblies identified by the numerals 40 and 40A differ in that the angular orientation of the retainer 46 and step 47 differs in angular orientation with respect to the ribs 42 thereof. In addition a plurality of index marks 49 are offset in the cutter holder or head assembly 40 from the position of the cutter holder 40A by the same six degree increment. Comparable distinctions exist between the cutter holders 43 and 43A. The precise manner of mounting the cutting plate or insert 44 may vary from one cutter holder to another. A discrete plate shaped member (not shown) may be provided to hold the insert 44. Obviously the contours of the step 47 will vary to accept cutting inserts 44 of different shapes. Although the cutter inserts have each been identified by the numeral 44, it will be understood that such alternative forms may be utilized in head assemblies intended for cutting at different angles. Such inserts may be rectangular, triangular or other geometric forms in various embodiments. The retainer 46 ordinarily will be provided with a key 51 which cooperates with a keyway 53 in the surface of the head assembly. A stud 55 depends from each of the head assemblies 40, 40A, 43, 43A as best shown in FIG. 9. 
     In the preferred form the apparatus will include six left handed head assemblies and six right handed head assemblies. Each cutter assembly will be provided with a plurality of index marks which are spaced at 6 degree increments. Only two left handed holders have been illustrated and two right handed holders have been illustrated of the preferred six left hand and six right hand assemblies. It has been found advantagous to provide maximum flexibility to provide graduations on each of six left handed assemblies which are each 6 degrees apart. The first assembly will have graduations starting with 0 degrees. A second head assembly will have graduations starting with 1 degree. Similarily the third, fourth, fifth and sixth head assemblies will have graduations starting with respectively 2, 3, 4, and 5 degrees. Six right hand assemblies will be similarly graduated. 
     The numerical values of the incremental positions for each of the six left hand head assemblies are as follows: 
     
         ______________________________________Numerical Values______________________________________(1)   0, 6, 12, 18, 24, 30, 36, 42, 48, 54, 60, 66, 72, 78, 84, 90.(2)   1, 7, 13, 19, 25, 31, 37, 43, 49, 55, 61, 67, 73, 79, 85, 91.(3)   2, 8, 14, 20, 26, 32, 38, 44, 50, 56, 62, 68, 74, 80, 86, 92.(4)   3, 9, 15, 21, 27, 33, 39, 45, 51, 57, 63, 69, 75, 81, 87, 93.(5)   4, 10, 16, 22, 28, 34, 40, 46, 52, 58, 64, 70, 76, 82, 88, 94.(6)   5, 11, 17, 23, 29, 35, 41, 47, 53, 59, 65, 71, 77, 83, 89,______________________________________ 95. 
    
     The numerical values of the incremental positions for each of the six right hand head assemblies are as follows: 
     
         ______________________________________(1)   90, 84, 78, 72, 66, 60, 54, 48, 42, 36, 30, 24, 18, 12, 6, 0.(2)   91, 85, 79, 73, 67, 61, 55, 49, 43, 37, 31, 25, 19, 13, 7, 1.(3)   92, 86, 80, 74, 68, 62, 56, 50, 44, 38, 32, 26, 20, 14, 8, 2.(4)   93, 87, 81, 75, 69, 63, 57, 51, 45, 39, 33, 27, 21, 15, 9, 3.(5)   94, 88, 82, 76, 70, 64, 58, 52, 46, 40, 34, 28, 22, 16, 10, 4.(6)   95, 89, 83, 77, 71, 65, 59, 53, 47, 41, 35, 29, 23, 17, 11,______________________________________ 5. 
    
     It will be seen that the user of the apparatus in accordance with the invention may achieve any integer value of any angle between 0 and 360 degrees. It will further be seen that because (1) the set screw 50 is utilized only to hold the cutting plate or insert 44 against the step 47 and because (2) the nut 57 has a beveled surface 59 for cooperation with the recess 26 of the cutter assembly 40, the insert 44 may be replaced by an operator after removal of the head assembly 40 and then the head assembly may be replaced in exactly the same angular orientation that it was in previously. This is of major significance where frequency cutter 44 replacements are necessary. In the prior art of the apparatus the loosening of the means for securing the cutter 44 normally resulted in the assembly coming completely apart and made it substantially more difficult to reassemble the apparatus in precisely the same angular orientation. 
     It will also be understood that the index mark 36 on the body portion 12 cooperates with the index marks 49 on the head assembly. The index marks 49 are ordinarily provided with numerical designations of the angle thereof as described above. These numerical designations ordinarily are quite small and thus have been omitted from the drawing. 
     The invention has been described with reference to its illustrated preferred embodiment. Persons skilled in the art of constructing lathe tool assemblies may, upon exposure to the teachings herein, conceive variations in the mechanical development of the components therein. Such variations are deemed to be encompassed by the disclosure, the invention being delimited only by the appended claims.