Abstract:
The present invention provides for a readily exchangeable flex tool for machining a workpiece. The flex tool includes a driver and an tool carrying body. The driver is coupled to the tool carrying body in a manner which allows the tool carrying body to have at least two degrees of freedom with respect to the driver. The tool carrying body includes an elongate pilot shaft, the elongate pilot shaft and tool carrying body having a longitudinal axis. The at least two rotational degrees of freedom allowing the longitudinal axis of the tool carrying body and elongate pilot shaft to be aligned with a longitudinal axis of a reference bore contained in the workpiece and slidably inserted therein.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     Not Applicable 
     STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH 
     Not Applicable 
     BACKGROUND OF THE INVENTION 
     This invention relates to a readily exchangeable, guidable tool such as those used in machining applications. Specifically, the present invention is directed to a rapid centering, misalignment tolerant, machining tool. 
     It is well known in the machining art that multiple machining operations require repositioning of the workpiece or repositioning of the machine spindle to precisely align the center line of a work piece reference bore with the centerline of the machine spindle, thereby ensuring a concentric and longitudinal orientation of the machining tool. When the alignment angle between the reference bore and the spindle is not accurate, a misalignment angle between the tool and workpiece results. This misalignment angle may result in the tool providing inaccurate or uneven machining. To prevent this, either the work piece or the machining spindle must be realigned, relative to one another, so as to negate the misalignment angle. To reposition the machine spindle generally requires manual realignment of the machine spindle relative to the workpiece or repositioning the workpiece relative to the machine spindle. Such repositioning is generally impractical as well as time consuming, and therefore expensive. To avoid the necessity of precisely realigning either the entire machine or the workpiece it would be desirable to have an invention which automatically repositions the tool carrying body alone thereby properly aligning the machining tool with the workpiece even when a misalignment angle is present and without requiring repositioning of the entire machine or workpiece. 
     To accomplish such a ‘tool only’ realignment, the present invention utilizes a flex joint between the machine driver and the tool carrying body. The tool carrying body contains an adjustable pilot shaft along. The pilot shaft engages a reference bore in the workpiece. This inventive configuration allows the tool carrying body to shift position as needed in order to ensure proper alignment between the tool and the workpiece. The specific components and functioning of the present flex tool are discussed in greater detail below. 
     BRIEF SUMMARY OF THE INVENTION 
     The present invention includes a tool carrying body which may be attached to a driver utilizing a flex joint. The tool carrying body contains an elongate pilot shaft which has a lower portion that may be slidably received into an existing reference bore of a workpiece. The upper portion of the elongate pilot shaft is adjustably or fixedly retained by the tool carrying body. The flex joint between the tool carrying body and the driver is coupled together by a guide collar which is loosely secured about the tool carrying body and removably secured to the driver. The guide collar is configured to be readily secured and removed to and from the driver. This provides the present invention to include tool carrying bodies with various characteristics to be readily interchanged on a driver. The guide collar provides a clearance between itself and the tool carrying body. The width of the clearance or the distance between the tool carrying body and the guide collar determines the amount of restriction to the range of motion of the tool carrying body. In addition the upper portion of the elongate pilot shaft may be configured to upwardly protrude through the tool carrying body in order to potentially engage the driver and thereby restrict the range of motion of the tool carrying body as well. Generally, the tool carrying body will have at least two degrees of rotational freedom which can be designed to provide any desired range of motion. In a preferred embodiment the range of motion of the tool carrying body may be restricted by the guide collar to between 0 and 15 degrees. 
     The combination of the flex joint and guide collar result in a flex tool which is capable of compensating for a wide range of misalignment angles between the centerline of the driver (i.e. spindle) and the centerline of the workpiece reference bore, by allowing the tool carrying body to be oriented with the reference bore via the inserted pilot shaft within the range determined by the guide collar. The flex joint between the tool carrying body and the driver provides the flex tool with the ability to compensate for misalignment angles between the driver and the workpiece reference bore without having to realign the entire machine or work piece surface. 
     In light of the aforementioned features, it is a goal of the present invention to provide for a flex tool capable of compensating for misalignment angles which may be present between the orientation of the longitudinal axis of a machine spindle and the longitudinal axis of a reference bore of a workpiece by realigning only the tool carrying body of the flex tool as opposed to the entire machining apparatus or work piece 
    
    
     BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS 
     A detailed description of the invention is hereafter described with specific reference being made to the drawings in which: 
     FIG. 1 is a side view perspective of the flex tool prior to coupling the guide collar to the driver; 
     FIG. 2 is a side view perspective of the flex tool showing the connected flex joint and the guide collar coupled to the driver; 
     FIG. 3 is an enlarged side view perspective of the guide collar; 
     FIG. 4 shows the ideal alignment of the longitudinal axes of the driver and reference bore; 
     FIG. 5 shows an example of a misalignment angle between the longitudinal axis of the reference bore and the longitudinal axis of the driver; 
     FIG. 6 shows the ability of the flex tool to compensate for the misalignment angle shown in FIG.  5 . 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     While this invention may be embodied in many different forms, there are shown in the drawings and described in detail herein specific preferred embodiments of the invention. The present disclosure is an exemplification of the principles of the invention and is not intended to limit the invention to the particular embodiments illustrated. 
     In FIG. 1 the primary components of the present invention are shown prior to assembly. The driver  10  has a spindle shaft  12  which, when used with a typical machining apparatus is fixedly connected to a machine spindle (not shown). When the flex tool is fully assembled, as indicated generally at  60  as shown in FIG. 2, the driver  10  is coupled to a tool carrying body  14 . The tool carrying body  14  has a substantially spherical upper portion or insert  16  and a lower portion  17 . Insert  16  is inserted into a upper portion or insert receiving region  18  of the driver  10 . In the embodiment shown and described herein, the connection of insert  16  and insert receiving region  18  results in flex joint having a ball-joint type configuration. It should be understood that the present invention may utilize any other flexible connection to achieve the desired rotational freedom for the tool carrying body as described herein. The insert receiving region  18  has a conical shape to ensure a continuous fit of the insert  16 . Preferably the insert receiving region  18  is shaped to provide a surface which ensures at least three points of contact between the insert  16  and the insert receiving region  18 . When properly fitted together the insert  16  and insert receiving region  18  form a flex joint. If the flex joint does not have a uniform coupling, vibrations or “chatter” may result when the flex tool is in use, adversely affecting the machining function. 
     A guide collar  20  is loosely disposed about the lower portion  17  of the tool carrying body  14 . In preferred embodiment the guide collar  20  has an inside threaded surface  22  (see FIG.  3 ), and the driver has an outside threaded surface  24 , as shown in FIG.  1 . The guide collar  20  is threadingly secured or screwed onto embodiments the guide collar and driver may be secured by a variety of means such as by utilization of a socket relationship, clamps, fasteners, or other attachment methods which may be known to one of ordinary skill in the art. 
     A retention ring assembly  26  prevents the tool carrying assembly from simply sliding out from the guide collar  20  and forces the insert  16  into uniform contact with the insert receiving region  18  when the guide collar is secured to the driver  10 . In the embodiment shown in FIGS. 1,  2 ,  5  and  6 , the insert  16  has an equatorial diameter equal to the lower portion  17 . The diameter of the insert  16  is restricted where the insert  16  and lower portion  17  are joined. Retention ring assembly  26  is held, as a result of this restricted diameter, on the tool carrying body between the insert  16  and the lower portion  17 . As previously stated the guide collar  20  is loosely disposed about the lower portion  17  of the tool carrying body  14 . However, the inside diameter of the guide collar  20  while obviously greater than that of the tool carrying body  14  is less than that of the outside diameter of the restriction ring assembly  26 . 
     In alternative embodiments the insert  16  may have various sizes and shapes. However, in any embodiment of the present invention the retention ring assembly  26  will be constructed to accomplish the various functions required as described herein, namely, retaining the guide collar  20  on the tool carrying body  14 , and providing an upward force on the insert  16  when the guide collar  20  and driver  10  are  10  secured together. 
     When the guide collar  20  is secured to the driver  10 , the restriction ring assembly  26  is compressed between the guide collar  20  and the insert  16 . As a result the restriction ring assembly  26  applies an upward force on insert  16  forcing insert  16  into uniform contact with insert receiving region  18  of the driver  10 . The force supplied by the restriction ring assembly  26  may be increased to ensure proper coupling of the insert  16  and the insert receiving region  18 , by including one or more tension rings  28  between the guide collar  20  and the restriction ring assembly  26 . A washer (not shown) may further be included between the tension rings  28  and the guide collar  20  to prevent undesirable wear on either the guide collar  26  or the tension rings  28 . As shown in FIG. 2 two tension rings  28  are shown, however this number may vary as desired. 
     It should be obvious to one of ordinary skill in the art that the force provided by the restriction ring assembly  26  may be modified in a variety of different ways besides the previously mention inclusion of one or more tension rings. The tension rings mentioned herein, as well as other devices known in the art, may have various physical characteristics which are known to increase or decrease the force supplied by the restriction ring assembly  26 . 
     When the flex joint is formed by securing the insert  16  to the insert receiving region  18  by securing the guide collar  20  to the driver  10 , the tool carrying body  14  theoretically has three degrees of rotational freedom and a virtually unlimited range of motion. However, in addition to the functions which the guide collar supplies to the present invention as described above, the guide collar may also serve to restrict the range of motion of the tool carrying body  14 . 
     As previously described the guide collar  20  is loosely disposed about the tool carrying body  14 . As best shown in FIG. 6, the area between the guide collar  20  and the tool carrying body  14  defines a clearance  29 . The tool carrying body  14  can only move within the confines of clearance  29  since the tool carrying body will come into contact with the guide collar  20  at some point. The guide collar  20  can be constructed to provide a clearance of varying widths and thus allow a variable range of motion relative to the longitudinal axis of the driver as shown in FIGS. 4 and 5. In the preferred embodiment disclosed herein the clearance  29  provides for a range of motion of the tool carrying body, based on the longitudinal axis of the tool carrying body, to be between 0 and 15 degrees relative to the longitudinal axis of the driver. 
     As best seen in FIGS. 1 and 2, insert  16  has a stop  30  which projects laterally therefrom. The insert receiving region  18  of the driver  10  is constructed so that the stop  30  is engaged by the driver  10  when the insert  16  and insert receiving region  18  are coupled together. Specifically, in the embodiment shown, the insert receiving region  18  includes a notched portion  32  which removably receives and engages the stop  30 . As a result of the stop  30  being engaged by the notch  32 , the tool carrying body  14  may be rotationally engaged by the driver  10  thereby preventing the tool carrying body  14  from rotating independently of the driver  10 . 
     In the embodiment shown the engagement between the stop  30  and notch is not a tight fit. Notch  32  provides excess space around stop  30  to ensure that tool carrying body  14  via insert  16  retains two rotational degrees of freedom relative to the driver  10 . As a result even when the stop  30  is engaged by the notch  32  the longitudinal axis of the tool carrying body  14  may be oriented independently of the longitudinal axis of the driver  10  to provide two rotational degrees of freedom. 
     As best seen in FIG. 2 an elongate pilot shaft  40  is held within the tool carrying body  14 . The elongate pilot shaft  40  has a lower end  42  which extends downward from the tool carrying body  14 . The lower portion  42  may be constructed to have a variable diameter in order to match the diameter of a wide range of reference bore types. In addition the elongate pilot shaft  40  may have a variable diameter, and as a result the tool carrying body  14  includes an adjustable securing means  44  which frictionally engages the elongate pilot shaft  40 . The securing means  44  is typically an adjustable screw or bolt threaded through the lateral surface of the lower portion  17 . The elongate pilot shaft  40  may also be constructed to facilitate the engagement of securing means  44  such as with the inclusion of depressions, notches, a ball detent, etc. 
     The elongate pilot shaft  40  is inserted into a reference bore  46  of a workpiece  48 . The reference bore may be an inherent part of the construction of the workpiece  48  or may be specially bored in preparation to receive a machining tool such as presently disclosed. When a workpiece such as shown in FIGS. 4-6 is brought into general alignment with a machining tool such as when a machinist or operator approximates or “eyeballs” the alignment, quite often the pilot shaft  40  is not precisely aligned with the reference bore  46 . This misalignment is referred to as a misalignment angle  50  and is best shown in FIG.  5 . If the misalignment angle  50  is not corrected the pilot shaft  40  may not be properly received by the reference bore  46 . If the misalignment angle  50  is slight it may be possible to force the pilot shaft  40  into the reference bore  46  but this may damage the workpiece  48  and result in improper machining. 
     As a result of the various features described above, the elongate pilot shaft  40  and the associated tool carrying body  14  can be readily repositioned in order to compensate for the misalignment angle  50 . By inserting the elongated pilot shaft  40  into the reference bore  46 , the longitudinal axis of the tool carrying body  14  and pilot shaft  40  will be repositioned to align with the longitudinal axis of the reference bore  46 . 
     The actual machining of the workpiece  48  is accomplished by the rotation of a tool such as a cutter insert  52  carried by the tool carrying body  14 . The cutter insert  52  may be an intrinsic part of the tool carrying body  14  but is more commonly connected to the tool carrying body  14  with a clamp or other attachment means. It should be obvious to one of ordinary skill in the art that the tool carrying body  14  may carry other tools or multiple configurations of tools in addition to or in place of cutter insert  52 . Furthermore, it should also be obvious that any type of cutter insert, besides that which is shown in the various figures may be utilized with the tool carrying body  14 . 
     This completes the description of the preferred and alternate embodiments of the invention. Those skilled in the art may recognize other equivalents to the specific embodiment described herein which equivalents are intended to be encompassed by the claims attached hereto.