Rotary cutting tool having an axial adjustment

An adjustable cutting assembly includes a wedge member extending transversely through a clearance opening in a sleeve portion of a cutting element adapter that is slidable supported on a rotary arbor. Radial motion of the wedge member can be used to shift the adapter axially on the arbor, thereby adjusting or controlling the depth of cut of the cutting element. An axially oriented locking bolt is used to clamp the wedge member between opposed guide surfaces on the adapter and arbor, so that during machining operations the tool assembly has the rigidity of a non-adjustable tool assembly.

FIELD OF THE INVENTION 
This invention relates to metal cutting tools, and particularly to 
adjusting devices for such tools, whereby the depth of cut can be varied 
or controlled. 
BACKGROUND OF THE INVENTION 
A face milling tool assembly is designed to form a flat surface on a work 
piece. Typically the work piece is mounted on a horizontal table so that 
it can be moved in a horizontal plane beneath a vertical axis rotary 
milling tool. Cutter teeth on the lower end surface of the rotating tool 
remove material from the upper face of the work piece; the horizontal 
table is moved back and forth so that the upper face of the work piece is 
smoothed, flattened, and machined to a desired dimension and surface 
finish. 
The present invention is directed to an adjusting device incorporated into 
a conventional face milling tool assembly, whereby the depth of cut can be 
varied or controlled in a relatively precise fashion. 
SUMMARY OF THE INVENTION 
The invention contemplates an adjustable tool assembly, e.g. a face milling 
tool assembly, wherein a cutting element adapter is axially adjustable on 
a rotary arbor, such that the depth of cut of the cutting element can be 
adjusted in a relatively precise fashion, e.g. within an accuracy of 
approximately 0.0005 inch or less. 
The tool assembly includes a wedge member that extends transversely through 
a clearance opening in the adapter, whereby the wedge member can be 
shifted in a radial direction across the tool rotational axis. The wedge 
member is sandwiched between a rotary arbor and the adapter. A radial face 
on the wedge member is slidable on a radial surface of the adapter. The 
wedge member has a second face that has a slight angulation relative to a 
radial plane taken through the tool rotational axis. The angulated face of 
the wedge member seats flatwise against a mating acutely-angled surface on 
the arbor. 
As the wedge member is adjusted transversely across the rotational axis of 
the tool assembly the wedging action of the wedge member produces a 
relatively slight axial adjustment of the cutter element adapter relative 
to the arbor. This axial adjustment can be used to precisely control the 
depth of cut of the cutting tool assembly.

DESCRIPTION OF A PREFERRED EMBODIMENT OF THE INVENTION 
The drawings show an adjustable cutting tool assembly 11 that includes a 
rotary arbor 13 designed to be mounted in a conventional drilling machine 
or lathe for rotation around a central axis 15. The arbor provides a 
supporting platform for a cutting element adapter 17 that is in axial 
alignment with the right face of the arbor (as viewed in FIG. 1). 
At its rightmost end the adapter 17 has a threaded stem 19 designed to 
mount a face milling tool (not shown). Typically the face milling tool 
comprises a cylindrical shank having a threaded hole that can be threaded 
onto stem 19; an end surface of the shank has one or more cutter element 
cartridges mounter therein, such that when the tool assembly is rotated 
around the central axis 15 the cutter elements wipe across the surface of 
a work piece to machine a flat surface thereon. In many cases the work 
piece is supported on a fixture that is movable in a plane normal to 
central axis 15, such that an extensive surface area of the work piece can 
be machined by the face milling tool. 
The depth of cut of the milling tool can be controlled or varied by 
adjusting the adapter 17 axially relative to arbor 15, as indicated by 
arrow 21 in FIG. 1. The present invention is concerned with the structure 
for achieving a precision axial adjustment of adapter 17 relative to arbor 
13. 
Referring more particularly to the construction of arbor 13, the arbor has 
a cylindrical side surface 23, a rear face 25, and a front face 27. A 
cylindrical axial hole 29 extends through the arbor from the rear face to 
the front face; a counterbore 31 is machined in rear face 25 to form an 
annular shoulder 32. 
Front face 27 of arbor 13 comprises two parallel flat guide surfaces 33 
acutely angled to an imaginary radial plane generated from rotational axis 
15. The angulation angle of surfaces 33 is preferably about five degrees, 
as indicated by arrows 35 in FIG. 1. Each guide surface 33 is formed by a 
shallow groove machined into the front face of the arbor; the side 
surfaces of the two grooves slidably contain or confine edge areas of the 
slidable wedge member 37 that is sandwiched between arbor 13 and adapter 
17. The wedge member can slide transversely across rotational axis 15, as 
indicated by arrows 39 in FIG. 1; however, the wedge member is otherwise 
retained or confined against any other type of movement (by the confining 
17). grooves formed on the facing surfaces of arbor 13 and adapter 
Adapter 17 comprises a cylindrical head 41 having a flat radial guide 
surface 43 facing the aforementioned angled guide surfaces 33 formed on 
arbor 13. Radial guide surface 43 is formed by a shallow groove machined 
into the rear (or left) face of cylindrical head 41. The opposing shallow 
grooves on adapter 17 and arbor 13 slidably guide the wedge member 37 for 
transverse slidable motion, as indicated by arrows 39 in FIG. 1. 
Extending leftwardly from cylindrical head 41 is a cylindrical sleeve 45. A 
slot-like clearance opening 47 extends transversely through sleeve 45 to 
freely accommodate wedge member 37. Opening 47 is wider than wedge member 
37 (as viewed in FIG. 1), so that the wedge member can move freely in the 
arrow 39 directions without encountering any resistance from sleeve 45. 
Sleeve 45 has an axially slidable fit in the aforementioned cylindrical 
hole 29, whereby the adapter 17 is centered on the arbor central axis 15. 
Sleeve 45 and hole 29 form a radial bearing for absorbing any radial loads 
that might be generated by the milling (cutting) operations. 
As previously noted, wedge member 37 is sandwiched between the front face 
of arbor 13 and the rear face of adapter 17. The rear end surfaces of the 
wedge member slidably mate with guide surfaces 33 on arbor 13, and the 
front end surface of the wedge member slidably mates with the flat radial 
surface 43 on adapter 17. The aforementioned grooves on the opposing 
surfaces of the arbor and adapter encompass the edges of the wedge member, 
and thus slidably confine the wedge member to radial motion, as indicated 
by arrows 39 in FIG. 1. 
An axially extending bolt 49 is threaded into an internally threaded area 
of sleeve 45, so that head 51 of the bolt can seat against shoulder 32 
formed by counter bore 31. A non-circular socket 50 is provided in head 51 
of the bolt to facilitate the bolt-turning action. When bolt head 51 
pressures against shoulder 32 the bolt draws adapter 17 leftwardly (in 
FIG. 1), thereby causing the wedge member 37 to be tightly clamped between 
arbor 13 and adapter 17. While the tool assembly is rotating (i.e. during 
a machining operation) bolt 49 will be in a tightened condition for 
producing a desired clamping action on wedge member 37. The arbor, 
adapter, and wedge member are rigidly connected together to act as a 
single unit. 
When bolt 49 is loosened the arbor and adapter relax from wedge member 37 
so that the wedge member can be moved in the direction indicated by arrows 
39 (FIG. 1). Upward motion of the wedge member (as viewed in FIG. 1) 
effectively reduces the axial dimension of the wedge member; downward 
motion of the wedge member effectively increases its axial dimension. 
After the desired motion of the wedge member has been achieved, bolt 49 
can be again tightened to cause the arbor and adapter to clamp the wedge 
member in its newly adjusted position. 
A set screw 53 is used to incrementally move (or adjust) the wedge member 
37. The set screw extends radially through a threaded opening in an ear 55 
that extends from the front surface of wedge member 37. As shown in FIG. 
2, the length of set screw 53 is substantially the same as the radial 
dimension of a recess 57 formed in adapter 17; the set screw can turn 
freely but it cannot move up or down in the recess. A slot 59 is formed in 
the upper edge of the adapter head 41 for access to a non-circular socket 
in the head of screw 53. To turn the set screw in either direction a 
turning implement, such as an Allen wrench, is inserted through slot 59 
into the head of the screw. 
The ends of the screw abut the end surfaces of recess 57, whereby turning 
motion of the screw causes ear 55 to advance up or down on the screw, 
depending on the direction of rotation of the screw. Ear 55 thus moves 
wedge member 37 in the arrow 39 direction. By making the length of screw 
53 the same as the radial length of recess 57, it is possible to 
essentially eliminate any lost motion between the screw rotation and the 
ear 55 movement. The person then is able to turn the screw a given amount 
and be assured that the wedge member 38 will move a certain distance so as 
to produce a given axial adjustment of adapter 17. Assuming that screw 53 
has forty threads per inch, one revolution of the screw will move wedge 
member 37 a distance of 0.025 inch. If angle 35 is five degrees, the 
corresponding axial adjustment of adapter 17 will be about 0.002 inch. 
Lesser axial adjustments of the adapter can be achieved by rotating screw 
53 a fraction of a turn; e.g. one quarter revolution will produce an axial 
adjustment of 0.0005 inch. 
when bolt 49 is in a slightly loosened condition the adapter will tend to 
shift away from the wedge member; excessive loosening of the bolt could 
cause the wedge member 37 to slip out of the confronting grooves in the 
adapter and arbor 13. To prevent such an action the arbor and adapter are 
tied together by four resilient tie elements 61. Each tie element 
comprises a pin 63 extending through aligned openings in the adapter and 
arbor. Threaded area 65 of each pin is in mesh with a threaded hole in 
arbor 17, such that the pin is rigidly anchored to the arbor while 
extending loosely through a hole in the adapter. An annular spring disk 67 
encircles each pin 63 to exert a resilient axial force on the head of the 
pin. 
The assembly of pin 63 and spring disk 67 tends to resiliently keep adapter 
17 from moving so far away from arbor 13 as would enable the wedge member 
to slip out of the associated guide grooves. Each resilient tie element 
(assembly) 61 keeps the wedge member in slidable contact with the adapter 
17 and arbor 13, whereby the wedge member slides smoothly in response to 
the turning motion of set screw 53. 
The invention is concerned primarily with the construction of wedge member 
37, and locking bolt 49 for clamping the wedge member in any selected 
position of adjustment. The tool assembly combines adjustability with the 
rigidity of a conventional non-adjustable construction. Wedge member 37 
extends transversely through the adapter so that the tool assembly is 
balanced. 
FIGS. 1 through 3 illustrate a preferred form of the invention. FIG. 4 
shows an alternate design embodying features of the invention. In the FIG. 
4 arrangement the flat face of the wedge member seats against a flat front 
face of the arbor. The angled wedge surfaces on the wedge member are in 
mating engagement with acutely angled guide surfaces on the adapter. 
The principal difference between the structures of FIGS. 1 and 4 is that in 
the FIG. 1 construction the wedge action takes place between the wedge 
member and arbor 13, whereas in the FIG. 4 construction the wedge action 
takes place between the wedge member and adapter 17. Both constructions 
use a locking bolt 49 to clamp the wedge member 37 to the arbor and 
adapter. FIG. 1 represents the preferred construction. However, it will be 
appreciated that some changes can be made in component design or 
arrangement while still practicing the invention.