Abstract:
A tool interconnect structure includes a spindle adapter, a rotary cutting tool, and a lock mechanism securing the rotary cutting tool to the spindle adapter. The spindle adapter has a face with a short hollow tapered shank at the face. The rotary cutting tool has a face for engaging the spindle adapter face and a tapered recess at the face for cooperating with the tapered shank. The lock mechanism includes a pair of blocks having shoulders at their ends adapted to engage annular grooves within the hollow tapered shank and within the rotary cutting tool. The blocks have threaded apertures therethrough and a screw having oppositely threaded end portions extends through the apertures. Rotation of the screw causes the shoulders to engage with and disengage from the grooves.

Description:
[0001]    This application is a continuation-in-part of copending application Ser. No. 09/390,909 filed Sep. 7, 1999, which claims the benefit of provisional application Serial No. 60/099,967 filed Sep. 11, 1998.  
     
    
     
       BACKGROUND OF THE INVENTION  
         [0002]    The present invention generally relates to cutting tools and, more particularly, to the connection of rotary cutting tools to spindles.  
           [0003]    Recently, a new interface between a rotary cutting tool and a spindle adapter was developed seeking solutions to various problems relating to interfaces using a steep angle taper and/or long taper. Particularly improvement was desired with regard to static and dynamic elasticity, tool change precision, and deformation at high speeds. As a result of this development, DIN standard 69893 issued which is directed to the dimensional relationships of a hollow short taper shank of a cutting tool and an associated recess in a spindle adapter. The DIN standard, however, does not address the structure or operation in which the tool shank can be gripped or expanded from its interior to press the shank against the mating recess of the adapter.  
           [0004]    A number of cutting tool manufacturers have developed different clamping or locking mechanisms for this interface between the cutting tool and the spindle adapter. Each manufacturer secures the lock mechanism to the spindle adapter within the tapered recess. Typically, the clamping mechanism includes a series of projections or fingers which can be selectively moved radially inward and outward. Once the tapered shank of the cutting tool is properly positioned within the tapered recess of the spindle adapter, an actuating screw of the clamping assembly provides radial movement of the fingers. Rotation of the screw in one direction moves the fingers radially outward into engagement with the internal surface of the shank hollow interior within an internal groove to form an interference in the longitudinal direction.  
           [0005]    When tool changeover is required, rotation of the actuator screw in the other direction retracts the fingers radially inward to remove the interference so that the cutting tool shank can be removed. The lock mechanism remains in place in the tapered recess of the spindle adapter, making the tapered recess into a narrow annular recess. A new cutting tool shank is then inserted into the tapered recess of the spindle adapter over the lock mechanism and the same process is followed to secure the cutting tool to the spindle adapter.  
           [0006]    While this interface may be an adequate solution for some cutting tool applications, particularly CNC machining centers, the interface may pose additional problems for other cutting tool applications, particularly dedicated spindles. One problem relates to the internal groove which has tolerances which are very difficult to maintain. As a result, the tool is very difficult and expensive to produce. Unfortunately, this internal groove tolerancing is only for the purpose of clamping the cutting tool. There is also some question as to the strength of the narrow wall thickness at the location of the internal groove.  
           [0007]    Another problem relates to cleaning. It is of primary importance that the mating, tapered surfaces of the spindle adapter recess and the cutting tool shank be kept clean. Any chips from the cutting operation that become lodged in the recess must be removed. The known lock mechanisms limit accessibility to the tapered recess in the spindle adapter as described above since the lock mechanism is mounted and retained therein. This is particularly a problem in dedicated spindle applications such as transfer line, dial, and trunion line machines which generally require manual tool changing and frequently have limited visual and physical access thereto. With the clamping mechanism located in the female end, it is virtually impossible to clean the spindle adapter recess. Operators cannot get their fingers inside to wipe the female socket. Chips, dirt, and coolant with small metal filings will most certainly freeze the clamping mechanism, making it impossible to remove the cutting tool. It is not practical to develop inside air blast cleaning for manual installations and external air blasts throw the chips back into the mechanism. Accordingly, there is a need in the art for an improved cutting tool interface.  
           [0008]    The invention set forth in copending application Ser. No. 09/390,909 filed Sep. 7, 1999 provides a cutting tool interface which solves at least some of the above-noted problems. The tool interconnect structure according to that invention includes a spindle adapter having a tapered shank, a rotary cutting tool having a tapered recess sized and shaped for cooperating with the tapered shank, and a lock mechanism securing the tapered shank within the tapered recess. By putting the tapered recess, the female portion, on the cutting tool it can be more easily cleaned because it is free of the machine.  
           [0009]    According to another aspect of that invention, a tool interconnect structure includes a spindle adapter and a rotary cutting tool. One of the adapter and the rotary cutting tool has a tapered shank and the other has a tapered recess cooperating with the tapered shank. A lock mechanism secures the tapered shank in the tapered recess. The lock mechanism includes a first retention stud secured within the tapered recess and at least one lock element within the tapered shank for selectively interconnecting with retention stud. By putting only a retention stud in the tapered recess, the female portion, the recess can be more easily cleaned because it no longer is just a thin annular groove. Additionally, the tapered shank no longer requires an internal groove so that it is easier to produce and has a greater wall thickness.  
         BRIEF SUMMARY OF THE INVENTION  
         [0010]    The present invention provides a cutting tool interface which has all of the invention described in the copending application and provides further advantages. The tool interconnect structure according to the present invention includes a spindle adapter and a rotary cutting tool. One of the adapter and the rotary cutting tool has a tapered shank and the other has a tapered recess cooperating with the tapered shank. A lock mechanism secures the tapered shank in the tapered recess. The lock mechanism secures the tapered shank in the tapered recess. The lock mechanism comprises at least one block element having first and second shoulders or wedges which are adapted to respectively engage complementary wedge faces on first and second abatements within annular grooves on the spindle adapter and the cutting tool. The locking mechanism is provided in a central recess defined by the spindle adapter and the cutting tool and is moved radially outwardly to lock the tapered shank in the tapered recess and is moved radially inwardly to permit the cutting tool to be removed from the spindle adapter. Radial movement is provided by a screw mechanism. Desirably, a pair of oppositely facing locking mechanisms are provided on a universal screw which advances the mechanisms radially outwardly when turned in one direction and retracts the mechanisms radially inwardly when turned in an opposite direction. The entire locking mechanism may be removed for cleaning.  
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0011]    [0011]FIG. 1 is an elevational view of a rotational cutting tool connected to a spindle adapter according to the present invention;  
         [0012]    [0012]FIG. 2 is an enlarged fragmented view, in cross-section, showing the interconnection of FIG. 1 in a locked condition;  
         [0013]    [0013]FIG. 3 is an enlarged fragmented view, in cross-section, similar to FIG. 2 but showing the interconnection of FIG. 1 in an unlocked condition;  
         [0014]    [0014]FIG. 4 is a perspective view of a locking element; and  
         [0015]    [0015]FIG. 5 is a cross-sectional view, the plane of the section being indicated by the line  5 - 5  in FIG. 4.  
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0016]    FIGS.  1 - 3  illustrate a rotary cutting tool interconnect structure according to the present invention. The interconnect structure includes a rotary cutting tool  10 , a spindle adapter  12  to which the rotary cutting tool  10  is secured, and a clamp or lock mechanism  14  releasably securing the rotary cutting tool  10  to the spindle adapter  12 .  
         [0017]    The rotary cutting tool  10  of the illustrated embodiment is a valve seat assembly tool but it is noted that other types of rotary cutting tools can be utilized within the scope of the present invention. The rotary cutting tool  10  includes a main body  16  and one or more cartridges or inserts  18  secured to the body to provide precision cutting surfaces mounted at predetermined positions for particular cutting operations. The illustrated cutting surfaces are for forming valve seats in an engine. Preferably, the inserts  18  are removable so that once the cutting surfaces become worn, the inserts  18  can be easily replaced and the new cutting surfaces are disposed at the proper angle and orientation.  
         [0018]    The main body  16  is adapted to be longitudinally located on a rotational axis  20  of a spindle for rotation with the spindle as described in more detail hereinafter. The main body is sized and shaped to provide the desired mass and strength for performing a particular cutting operation. A first or rear end of the rotary cutting tool  10  has a shoulder portion  21  which forms a rear face  22  substantially perpendicular to the rotational axis  20 . The rear face  22  limits insertion of the spindle adapter  12  into the rotary cutting tool  10  as described in more detail hereinafter. The shoulder portion  21  also forms a front face  23 . A land portion  23   a  is disposed on the forward side of the shoulder and has a diameter smaller than the shoulder portion. Recesses are provided in the land portion which are adapted to receive the removable inserts  18 . A nose portion  23   b  is disposed on the forward side of the land portion  23   a  to form a second or forward end which tapers to a minimum diameter. The second end is dimensioned for receipt in an opening of an engine head in which valve seats are to be formed or cut by the rotary cutting tool  10 .  
         [0019]    As best shown in FIGS. 2 and 3, a tapered recess  24  is formed in the rear face  22  at the first end of the cutting tool main body  16  and centered on the rotational axis  20 . The tapered recess  24  has a planar bottom wall  26  substantially perpendicular to the rotational axis  20  and a tapered side wall  28  which decreases in diameter from a maximum diameter near the rear face  22  to a minimum diameter near the bottom wall  26 . The tapered recess  24  is sized and shaped to provide a mating fit with the spindle adapter  12  as described in more detail hereinbelow. A longitudinally extending bore or opening  30  is centered on the rotational axis  20  and opens into the tapered recess  24  through the bottom wall  26 . The wall  26 , the bore  30 , and a sloping face  31  of an annular groove  31   a  form a locking surface for the locking mechanism  14  as will be explained in greater detail.  
         [0020]    As shown in FIG. 1, the spindle adapter  12  has a body  32  adapted to be longitudinally located on the rotational axis  20  for rotation with the spindle as described in more detail hereinafter. The spindle adapter  12  can be an integral portion of the spindle or a separate component secured thereto. The body  32  is sized and shaped to provide the desired mass and strength for cooperating with the rotary cutting tool to perform the particular cutting operation. A nose portion  33  of the adapter  18  has a diameter smaller than a first shoulder portion  35 . The nose portion  33  forms a forward face  34  substantially perpendicular to the rotational axis  20 . The forward face  34  cooperates with the rear face  22  of the rotary cutting tool  10  to limit insertion of the spindle adapter  12  into the rotary cutting tool  10  as described in more detail hereinafter.  
         [0021]    As best shown in FIGS. 2 and 3, a tapered shank  36  is formed at the forward face  34  of the spindle adapter body  32  and centered on the rotational axis  20 . The tapered shank  36  has a planar front edge substantially perpendicular to the rotational axis  20  and a tapered side wall  40  which increases in diameter from a maximum diameter near a front edge  38  to a maximum diameter near the forward face  34 . The tapered shank  36  is sized and shaped to provide a mating fit with the cutting tool tapered recess  24  as described in more detail hereinbelow.  
         [0022]    The tapered shank  36  is hollow and has an annular groove  42  which forms a sloping face  44 . The face  44  forms a locking surface for the locking mechanism  14  as will be explained in greater detail.  
         [0023]    The tapered shank  36  is sized to have a shallow angle similar to those required by DIN 69893 (for short tapered, face contact, hollow shank connection). The taper of the shank  36  is preferably about 10/1 and is preferably in the range of about 1½ degrees to about 3 degrees. The tapered shank  36 , however, has a length which is shorter than those required by DIN 69893. For typical cutting tools, the length of the tapered shank  36  is preferably less than {fraction (7/16)} inch and is preferably greater than ¼ inch.  
         [0024]    The lock mechanism  14  includes a pair of wedge blocks  46  and  48 . The blocks  46  and  48  are substantially identical and, with particular reference to FIGS. 4 and 5, only the block  46  will be described in detail. The block  46  includes a body portion  50  having first and second shoulder portions  52  and  54 . The shoulder portions  52  and  54  respectively define wedge faces  56  and  58  which are adapted to cooperate with the sloping faces  44  and  31 , respectively, to lock the cutting tool  10  to the spindle adapter  12 , as will become apparent.  
         [0025]    The blocks  46  and  48  are provided with oppositely threaded bores  60  and  62  which are oppositely threaded. A universal screw  64  ties the blocks  46  and  48  together and has oppositely threaded end portions which, upon rotation in a first direction, will draw the blocks  46  and  48  toward each other and which, upon rotation in an opposite direction, will move the blocks  46  and  48  apart. Each end of the screw  64  is provided with a slot  66  so that turning access may had to either end of the screw  64  through radial bores  68  and  70  which extend through the tapered connection between the tool  10  and the adapter  12 . Other mechanisms such as cams may be employed to move the blocks into and out of contact with the sloping faces  44  and  31 . Each block  46  and  48  is provided with a locating pin  72  and each pin  72  is received in radially extending locating slots  74  in the spindle adapter  12 . This arrangement ensures that the axis of the screw  64  is aligned with the bores  68  and  70  upon installation of the blocks  46  and  48  and during operation.  
         [0026]    [0026]FIG. 2 illustrates the lock mechanism  14  in its locking condition with the blocks  46  and  48  in a separated position and with the wedge faces  56  and  58  in locking contact with the sloping faces  44  and  31 , respectively. In order to move the lock mechanism  14  to the unlocked position illustrated in FIG. 3, a screwdriver is inserted in either of the bores  68  and  70  and the screw  64  is rotated to draw the blocks  46  and  48  together and to a position providing axial clearance between the wedge faces  56  and  58  and the sloping faces  43  and  31 .  
         [0027]    While the invention has been shown and described with respect to particular embodiments thereof, those embodiments are for the purpose of illustration rather than limitation, and other variations and modifications of the specific embodiments herein described will be apparent to those skilled in the art, all within the intended spirit and scope of the invention. Accordingly, the invention is not to be limited in scope and effect to the specific embodiments herein described, nor in any other way that is inconsistent with the extent to which the progress in the art has been advanced by the invention.