Variable tool bit holder

A variable tool bit holder which takes the place of up to eight standard tool bit holders for machining a workpiece including a shank member having a generally elongated rectangular configuration, and a groove positioned on an end portion of the shank member and comprises an end groove portion extending across an end surface of the shank member and side groove portions extending horizontally on the left and right side surfaces of the shank member toward the opposing end surface for a distance at least equal to the end surface groove portion; a support blade having top and bottom surfaces each defined by a frontally disposed V-shaped bit-receiving forward edge portion and a rearwardly disposed planer top surface disposed above the plane of the bit-receiving surface; a transversely projecting elongated rib extending longitudinally along the inner side of the support blade and adapted to be inserted in a selected groove portion and releasably secured thereto; an insert bit having opposing cutting tips and a V-shaped bottom edge adapted to be received in the V-shaped bit-receiving portion of the support blade; and a clamp which is releasably attachable to a portion of the surface of the shank member adjacent to the top surfaces of the bit and support blade whereby a portion of the clamp clamps the bit member between the support blade and the clamp and the top surface of the support blade.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
The present invention relates generally to machine tools and more 
particularly to improvements in a tool bit and tool holder assembly which 
provides for a plurality of tool bit cutting positions while the tool bit 
holder is rotatably mounted in conventional commercially available 
machines such as a lathe. 
2. Description of the Prior Art 
This invention relates to the art of metal cutoff and particularly that 
type of metal cutoff wherein a rigid cutoff tool is advanced into the 
periphery of a rotating workpiece so as either to effectuate cutoff of a 
portion of the workpiece or to place a groove in the same as required. 
With respect to the prior art holder, when a workpiece is to be treated in 
various locations or positions by the tool bit blade to perform the 
operation of shaping, facing, chamfering and the like, from different 
directions from the holder such as straight right or straight left and end 
right or end left the tool holder and insert must be replaced in the lathe 
machine with a separate tool holder and the respective insert for each 
position. 
Another disadvantage of the prior art tool bit holder is that separate and 
individual tool holders must be used to provide for different center 
heights when mounted on the tool post of a lathe machine, for example. 
The following U.S. Patents are believed to exemplify the present state of 
the art with respect to tool bit holders: U.S. Pat. Nos. 3,603,185; 
3,815,454, 4,332,513; 4,599,923; 4,640,159. 
While such prior art devices provide improvement in the areas intended, 
there still exists a need for a tool bit holder device which overcomes the 
disadvantages of the prior art while providing utility features which 
provide new and useful advantages and improvements not heretofore 
disclosed. 
Accordingly, a principle desirable object of the present invention is to 
provide a new and improved tool bit holder device which overcomes the 
disadvantages of the prior art devices. 
Another desirable object of the present invention is to provide a new and 
improved tool bit holder wherein the tool holder body permits a single 
blade to be mounted in different positions about the holder 
A further desirable object of the present invention is to provide a tool 
bit holder shank which allows the tool bit holder to be positioned for 
different center heights. 
A still further desirable object of the present invention is to provide a 
single tool bit holder which is constructed and arranged to provide 
various machining operations that cannot be performed by a conventional 
tool bit holder. 
Another desirable object of the present invention is to provide a tool bit 
holder including the foregoing desirable objects which is simple in 
design, inexpensive to manufacture, rugged in construction, easy to use 
and efficient in operation. 
SUMMARY OF THE INVENTION 
The broad purpose of the present invention is to provide a variable tool 
bit holder which takes the place of up to eight standard tool bit holders 
and which can be mounted in conventional tool bit holding machines. The 
variable tool of the present invention for machining a workpiece includes 
a shank member having a generally elongated rectangular configuration in 
elevation including first and second opposing end surfaces, top and bottom 
surfaces, and left and right surfaces. A groove is positioned on an end 
portion of the shank member and comprises an end groove portion extending 
across an end surface of the shank member and side groove portions 
extending horizontally on the left and right side surfaces of the shank 
member toward the opposing end surface for a distance at least equal to 
the end surface groove portion. Also included is a support blade having 
top and bottom surfaces each defined by a frontally disposed V-shaped 
bit-receiving forward edge portion and a rearwardly disposed planer top 
surface disposed above the plane of the bit-receiving surface; a 
transversely projecting elongated rib extending longitudinally along the 
inner side of the support blade and adapted to be inserted in a selected 
groove portion and releasably secured thereto; an insert bit having 
opposing cutting tips and a V-shaped bottom edge adapted to be received in 
the V-shaped bit-receiving portion of the support blade; and a clamp which 
is releasably attachable to a portion of the surface of the shank member 
adjacent to the top surfaces of the bit and support blade whereby a 
portion of the clamp clamps the bit member between the support blade and 
the clamp and the top surface of the support blade.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENT(S) 
Referring now to the drawings and more particularly to FIGS. 1 and 2, there 
is shown certain components of the variable tool holder of the present 
invention to illustrate initially the cutting positions while the tool bit 
holder is mounted in a conventional machine such as a lathe (not shown) 
for machining a workpiece (not shown). 
The variable tool bit holder, generally indicated by the numeral 10, 
includes a tool body or shank member 12 which preferably has a generally 
elongated rectangular configuration in elevation having a first or front 
end surface 14, an opposing second or rear end surface 16, top and bottom 
surfaces 18 and 20 and left and right side surfaces 22 and 24. 
A groove, indicated generally by the numeral 26 is positioned about an end 
portion of the shank member 12. The groove 26 comprises an end groove 
portion 28 which extends across the end surface 14 of the shank member 12, 
a right side groove portion 30 extending horizontally along the right side 
24 of the shank member 12 and a similar left side groove portion 32 
extending along the left side 22 of the shank member 12. 
The tool bit holder includes a support blade member 34 comprising an inner 
rectangular section I and an outer horizontally T-shaped section 0 in 
which the section 35 extends forwardly beyond the rectangular section R 
which together form similar top and bottom surfaces each defined by a 
frontally disposed V-shaped bit-receiving forward top edge portion 36 and 
a rearwardly disposed planar top surface 38 disposed above and partially 
to the inner side of the plane of the bit-receiving surface 36. The 
correspondingly similar bottom surfaces are respectively indicated as 36A 
and 38A. The support blade 34 is provided with a transversely projecting 
elongated rib 40 extending longitudinally and horizontally along the inner 
side 42 of the support blade member 34. 
The insert bit 44 is preferably configured to have an elongated body 46 
which terminates in opposing ends forming cutting tips 48 and 50, an upper 
surface 49 and a V-shaped bottom edge surface 52 adapted to be received in 
the V-shaped bit-receiving surfaces 36 and 36A of the support blade 34. 
Referring again to FIG. 1, a clamp member 54 is provided and has a 
block-like configuration which is sufficiently wide as shown by the dotted 
line area W to extend sufficiently beyond the shank top surface 18 to form 
a clamping contact with the top surfaces of support blade 34 and the 
insert bit 44 when attached to the shank. The clamp member 54 is provided 
with a bore or hole 56 through which the bolt 58 is passed for threaded 
clamping engagement with the threaded bore 60 which extends down through 
the top surface 18 of the shank member 12. In a similar manner the support 
blade 34 is provided with a bore 62 through which bolt 64 is passed for 
threaded engagement with one of the selected threaded bores, such as 66, 
which extends from one side through to the other side of the shank member 
12 or the front threaded bore 68 when the support blade 34 is to be 
attached to the front of the shank member 12. 
With respect to the variable tool bit holder 10 of the present invention as 
illustrated in FIG. 1, the support blade 34 is constructed and arranged so 
that it can be attached to the right side 24 of the shank member 12 as 
indicated by the arrow A and when selected attached to the left side 22 of 
the shank member 12 by simply inverting the support blade 34 as shown by 
the arrow B position. 
Similarly, the support blade 34 can be quickly and easily attached to the 
front or first end 14 of the shank member 12 in either a right or left 
position as indicated by the arrow positions C to D or D to C and as 
illustrated in a partially attached arrangement in FIG. 2. 
Referring now more particularly to FIGS. 3-6, there is illustrated an 
example of the tool bit holder of the present invention which has been 
selected to have the support blade 34 and insert bit member 44 attached to 
the side 24 of the shank member 12. The support blade 34 is attached to 
the shank member 12 by inserting the rib member 40 into the groove 30 and 
inserting the bolt 64 into the bore or aperture 62 and into the threaded 
opening in bore 66. The bit 44 is then inserted into the V-shaped 
receiving forward edge portion 36 of the support blade 34. Then the clamp 
member 54 is attached to the top surface 18 of the shank member 12 by 
inserting the bolt 58 through the bore or aperture 56 into the threaded 
opening or bore 60. As best seen in FIG. 4, the portion W of the clamp 
member 54 extends sufficiently beyond the side surface 24 of the shank 
member 12 to secure that portion W of the clamp member 54 in contact with 
the top surface 49 of the bit member 44 and the top surface 38 of the 
support blade 34. 
Referring now more particularly to FIGS. 7-9, there is illustrated another 
embodiment of the present invention in which the variable tool bit holder 
in accordance with the novel features of the present invention illustrates 
the selection of attaching the support blade 34 and the bit member 44 to 
the front left position of the shank member 12. It is believed to be 
readily apparent that the assembly of variable tool bit holder in this 
selected front position is done quickly and efficiently in the same manner 
as described with respect to FIGS. 3-6. 
Referring now more particularly to FIG. 10, there is illustrated an 
alternate embodiment of the tool body shank member of the present 
invention referred to in FIGS. 10-13 as 12A. As shown, the shank member 
12A is similar in all respects to shank member 12 as described with 
respect to FIGS. 1-9 hereinbefore except that it includes an enlarged end 
section 70 which extends upwardly from the surface 18 of the shank member 
12A. In the embodiment illustrated, the non-enlarged section as shown by 
the arrow c of the shank member 12A is, for example, 1.000 inch and the 
enlarged portion as shown by the arrow b adds, for example, 0.250 inch so 
that the total width or height as shown by the arrow a of the enlarged 
section of the shank member is 1.250 inches. As shown in FIG. 11, the tool 
bit holder 12A of FIG. 10 when provided with the support blade member 34, 
insert bit member 44 and clamp member 54 components and attached to the 
tool post 72 of a lathe machine provides the exact center height, as shown 
by the arrow d, of 1.250 inches from the top surface 74 of the tool post 
72 to the center line 76 of a lathe machine 78 (only partially 
illustrated) whereby the top of the cutting tip 48 is in the horizontal 
plain of the center line 76 of a lathe machine. As used in the 
specification and claims the term center height shall mean the distance 
between the surface of the shank member (18 or 20) brought into contact 
with the support surface 74 of the tool post and the top surface of the 
bit member which is equivalent to the height or distance from the support 
surface 74 of the machine tool post 72 and the center line 76 of the lathe 
machine. 
Referring now more particularly to FIGS. 12 and 13, there is illustrated an 
alternate feature of the tool bit holder 12A of FIG. 10. As shown, when 
the distance as shown by arrow e between the top surface 74 of the tool 
post 72 and the center line 76 of the lathe machine 78 is 1.000 inch, the 
tool bit holder shank 12A as shown in FIG. 10 needs only to be inverted as 
shown in FIG. 12 and the components 34, 48 and 54 attached to the left 
side 22, for example, and the shank member 12A attached to the top surface 
74 of the lathe machine 78 so that the enlarged end section 70 extends 
beyond the top surface 74 and is brought into contact with the vertical 
front end surface 80 of the tool post member 72. This arrangement results 
in lowering the upper surface portion 49 of the top of the cutting tip 48 
of the bit member 44 0.250 inch so that it is in the horizontal plain of 
the center line 76 of the lathe machine and also one (1.000) inch above 
the top surface 74 of the tool post 72 as shown by the arrow e. 
In summary, the variable tool bit holder of the present invention provides 
for machining workpieces in numerous ways without the necessity of having 
to have a number of tool bit holders with each one limited to perform only 
one function. 
While the invention has been described with respect to preferred 
embodiments, it will be apparent to those skilled in the art that changes 
and modifications may be made without departing from the scope of the 
invention herein involved in its broader aspects. Accordingly, it is 
intended that all matter contained in the above description, or shown in 
the accompanying drawing shall be interpreted as illustrative and not in 
limiting sense.