Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
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Description
D~flectable Holding Assembly
Technical Field
This invention relates to a holding assembly
~ 5 for connecting a shaft to a drive member, and more
particularly to a deflectable tool holding assembly for
positioning the tool in a preselected position.
Background Art
Holding assemblies are known which connect a
cutting tool, shaft, or the like to a rotary drive
member. Such assemblies include, on one end portion a
fastener, for example, threads, splines, collets, etc.,
which securely connects the holding assemblies to a
spindle or shaft of the prime mover. On the other end
of such an assembly is provided a fastening device which
is connectable to an adjacent end portion of the shaft
or cutting tool and securely holds the cutting tool or
shaft in place.
Typically, in such holding assemblies, the
2~ axis of rotation of the holding assembly and the axis of
rotation of the cutting tool or shaft are-substantially
in alignment at their connection or proximal ends. How-
ever, due to manufacturing tolerances,or damage to the
cutting tool or shaft in transportation or operation,
frequently the cutting tool or shaft itself may not be
perfectly straight throughout its length. Therefore, the
axis of rotation of the distal end of the cutting tool
; shaft ig`not concentric or in alignment with the axis of
rotation at the proximal end. This is often referred to
by those skilled in the art as runout. As a result, the
cutting tool or shaft will wobble or stated another way,
the axis of revolution at the distal end will generate
or describe a circle rather than a point.
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In the case where the holding assembly is used in
a machining operation and the cutting tool is a reamer the
wobble at the distal end of the reamer would cause, for
example, an oversized bore in the workpiece being machined
and possibly damage to the reamer itself.
In the situation where the holding assembly
connects the drive member to a shaft, for example, of a
hydraulic pump, the wobble would cause vibration and
radial loading resulting in failure of the pump and drive
member.
The present invention is directed to overcoming
one or more of the problems as set forth above.
Disclosure of Invention
In one aspect of the present invention, a holding
; 15 assembly is provided for connecting a shaft to a drive
means, said assembly having a body, said body having a
first end portion connectable to the drive means, a second
end portion connectable to the shaft and a middle portion,
the improvement comprising: first and second spaced apart
flanges extending outwardly from the middle portion of the
body, said body being a unitary piece; and means for con-
trollably urging the flanges and controllably deflecting
the middle portion of body and moving the second end por-
tion of said body to preselected relative positions in re- -
sponse to deflection of said middle portion.
Brief Description of Drawing
FIG. 1 is a diagrammatic view of the holding
assembly with a portion in fragmentary section.
FIG. 2 is a diagrammatic end view of the holding
assembly as viewed along line II-II of FIG. 1.
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Best Mode for arryin~ Out the Invention
Referring to the drawings, a holding assembly 10,
includes a body 12 having a first end portion 14
connectable to a drive means 16 and a second end portion
18 connectable to a shaft 20 and a substantially cylin-
drical middle portion 21. The drive means 16 may be of
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any suitable form well known in the prior art.
The drive means 16 includes a shaft 22 pre-
ferably having a tapered bore 24 for receiving therein
a taper 26 on the first end portion 14 of said holding
assembly 10. The taper 26 on the first end portion 14
is urged into contact with the tapered bore of the
~ shaft 22 by a thre~ded member 28 screw threadably
engaged in a threaded aperature 30. Although the
preferred embodiment of the connection at the drive means
has been described in some detail, it is to be understood
that there are other connecting arrangements, such as
threads, splines, collets, etc., which are suitable.
The shaft 20, preferably shown as a cutting
tool such as a reamer, has a proximal or first end
portion 32, closely slidably impaling a bore 34 axially
disposed in the second end portion 18 of the holding
assembly 10. A flat 36 is provided on the first end
portion 32 of the shaft 20 against which set screws 38
bear. The set screws 38 secure the shaft 20 to the
second end portion 18 of the holding assembly 10.
A distal or second end 40 of shaft 20 has a
plurality of cutting members 42 thereon suitable for
removing material from a workpiece, not shown.
- It is to be noted that although the shaft has
been described as a cutting tool other shaft embodiments
such as drive shafts, pump drive shafts, wheel drive
shafts, etc., are applicable for use with this invention.
The holding assembly 10 has a central axis of
rotation 44 substantially in alignment with a central
30 axis 46 of the first end portion 32 of shaft 20, and a
central ~axis of rotation 48 of the shaft 22 of drive
means 16. The second end or distal end 40 has a central
axis 50 which is not coincident or in alignment with the
central axis 44, 46 or 48. Therefore, rotation of the
drive means 16 and holding assembly 10 about the central
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axis 48 would result in the end 40 of shaft 20 to
revolve or wobble. Stated another way, the central axis
50 of end 40 will describe a circle of revolution rather
than a point of rotation. This is often referred to in
the machining industry as runout.
To eliminate the aforementioned problem the
~ holding assembly 10, includes a means 52 for selectively
controllably deflecting one of the first and second end
portions 14,18 to preselected relative positions wherein
the runout at end 40 is eliminated. The deflecting
means 52 preferably comprises a first and second spaced
apart flanges 54,56 each extending outwardly from the
middle portion 21 of the body 12. The flanges 54,56 are
preferably annular members but could be individual tabs,
projections and the like. The flanges 54,56 are
connected to the middle portion 21 of the body 12 and
include a bearing surface 58 and an outside surface 60.
The bearing surface 58 preferably extends substantially
normal to the axis 44. The outside surface 60 is pre-
ferably cylindrical in shape and has a diameter ofgreater dimension than the middle portion 21 between
the spaced apart flanges 54,56.
The deflecting means 52 further includes a
means 62 for controllably urging the flanges 54,56 and
controllably deflecting one of the first and second end
portions 14,16 to preselected relative positions. The
urging means 62 preferably comprises an elongated
- cylindrical member 64 having a threaded outer surface
66, a curvilinear end portion 68 and a socket end
portion 70. The curvilinear end portion 68 is a bearing
surface èngageable with one of said bearing surfaces 58.
The curvilinear end portion 68 is so shaped to insure
point contact with the bearing surface 58 even when the
bearing surface is urged from its neutral no load
position. The socket end portion 70 is preferably pro-
vided with a hexagonal recess 72 for receiving a
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wrench or the like.
The cylindrical member 64 is screw threadably
disposed in a threaded aperature 74 in flange 54. The
aperature 74 and dependently the member 64 is positioned
substantially n~rmal to the bearing surface 58 and
preferably between the flanges 54,56. Therefore, the
`- cylindrical member 64 is rotatably moveable along its
threaded outer surface 66 between a position wherein the
curvilinear end portion 68 is spaced from the bearing
surface 58 and a position wherein the curvilinear end
portion 68 is in selective controllable, forceable
contact with said bearing surface of said flange.
It is to be noted that the cylindrical member
64 may be screw threadably engaged in aperatures in
either flange 54,56 and engageable with the bearing
surface 58 on the other.
Preferably, there are at least three equally
arcuately spaced apart threaded aperatures about the
flange 54 and a cylindrical member 64 screw threadably
engaged in each of said aperatures. It can therefore
be seen that the curvilinear end portion 68 of the
cylindrical members 64 are each individually selectively
moveable into contact with the flanges 54,56 at
discrete spaced apart locations, with a desired magnitude
of force to stress the flanges 54,56 and deflect one of
the first and second end portions 14,18 of the body 12.
Note that the end portion 14,18 that will move is
determined by the physical restraints placed upon the
end portions. The end portion 14,18 easiest to move
will move first. Three spaced apart points are required
to define a plane and there are at least three spherical
end portions 68 provided herein.
Heretofore we have provided threaded cylindri-
cal members 64 to forceably engage the flanses 54,56 and
deflect the end portions 14,18. It is to be understood
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that other embocliments, such as cams, clamps and the
like, are capable of providing forceable engagement with
the flanges 54,'i6, and such embodiments do not depart
from the spirit of the invention.
Industrial Applicability
In operation, tne holding assembly lQ is
secured to the shaft 22 of the drive means 16 by drawing
the taper 26 on first end portion 14 into forceable
contact with the tapered bore 24 of shaft 22 via thread-
ed member 28,
The shaft 20 and specifically the first endportion 32 is inserted into the bore 34 on the second
end portion 18 of holding assembly 10. The shaft 20
is rotated in the bore 34 until the flat 36 faces the
set screws 38. The set screws 38 are then urged into
contact with the flat 36.
The operator then rotates the entire holding
assembly 10 and checks the runout of the shaft 20 at the
second end 40. If the central axis 50 of the second end
40 is not in alignment with the central axis of rotation
:~ 44,46,48 of holding assembly 10, shaft 20, or shaft 22,
runout will be observed.
.. The operator will then stop rotation of the
assembly 10, noting the location of the runout and adjust
each of the urging means 62 until the central axis 50 of
. the second end 40 of shaft 20 is in alignment with at
least the central axis of rotation 48 of shaft 22.
As previously discussed, adjustment to
remove runout at the second end 40 of shaft 20 is
achieved by deflecting the second end portion 18 to a
: . position determined by the location of the runout at
` the second end 40. Deflection of the second end
portion 18 is specifically achieved by selectively
rotating each of the plurality of cylindrical 64 members
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separately but sequentially into forceable contact with
the flanges 56, which tends to force the flanges 54,56
apart at the location of contact. By adjusting each
cylindrical member 64 in this manner the exact angle
of deflection and magnitude may be ach~eved.
When the holding assembly 10 ~s adjusted to
- eliminate runout at the second end 40 of shaft 20,
runout may be introduced at some other location such
as in the middle portion 21 of the holding assembly 10,
or first end port~on 32 of shaft 20, etc. This will
not be detrimental to the operation of the apparatus
since the central axis 48 of the shaft 22 of the
drive means 16 and the central axis 50 o~ the second
end 40 of shaft 20 are in alignment. Thus, the input
and output are in alignment at the critical locations.
Upon completion of the adjustment, the
operator will rotate the holding assembly and check
for runout once again. If further adjustment is needed,
the same procedure as discussed above will be followed.
Other aspects, objects and advantages of this
invention can be obtained from a study of the drawings,
the specification, and the appended claims.
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