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Патент USA US2408917

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Oct. 8, 1946e
A, (3201'
BIT
SHARPENER
‘Filed Oct. 6, 1944
2,408,916
.
'
2 Sheets-Sheet 1 -
INVENTOR.
ANDRE’ CROT
Patented Oct. 8, 1946
UNITED STATES PATENT 0mm:
2,4Q8,916
BIT SHARPENER
Andre Crot, North Hollywood, Calif, assignor to
Lockheed Aircraft Corporation, Burbank,
Calif.
Application October 6, ‘1944, Serial No. 557,412
4 Claims.
(or. 51-2s2)
1
This invention relates to special machine toolsg
for machining helical surfaces of any desired pitch ‘
and relates more particularly to and ?nds its
most frequent application to the forming and
sharpening of spiral or helical cutting edges of
tools such as drills, router bits, milling cutters,
2
dle and spindle drive shaft being constructed to
snugly telescope to provide for limited axial re
ciprocation with respect to one another and com
mon rotation together. Common rotation of the
spindle drive shaft I5 and the tubular spindle
I4 is effected by means of a pair of keys it re
tained in suitable recesses on the inside surface
of the tubular spindle and adapted to slide axial
ly within a pair of elongated key-ways l7 formed
in the surface of the drive shaft IS.
10
ally employed for the purpose of resurfacing or
The tubular spindle I4 is reciprocatably and
sharpening spiral or helical cutting edges of drills,
rotatably supported in a bushing l8 which is in
router bits, milling cutters, reamers, and the like
turn retained within a bearing support or bear
tools, with the result that such operations were
ing holder 19 which is inserted and suitably
slow and inefficient and resulted in inaccurately
bolted in place, as shown at 20 in an opening
15
shaped, poorly operating tools.
2| located through the wall of the forward end
and reamers.
Heretofore a manual manipulation of the tool
with respect to a grinding stone has been usu
It is an object of this invention to overcome
of the housing In.
'
the disadvantages of the manual method and
As best shown in Figures 3 and 4 the tubular
other methods heretofore employed for recondi
spindle is provided with a ?ange 22 on its outer
tioning and machining spiral or helical edged tools
end to which may be bolted a chuck body as shown
by providing an automatic machine for this pur 20 at 23. Any suitable chucking means may be em
pose which will be accurate, e?icient and fast in
ployed depending upon the type of workpiece or
operation.
tool to be machined but for convenience of illus
The objects of this invention are attained in
tration herein a split collet type of chuck is
general by a machine capable of imparting, be
shown and described. A split collet grip-assem
tween limits, any desired one of an in?nitely 25 bly providing a plurality of radially positioned
jaws is retained as a unit within the collet body
reciprocation motions to a work piece such as a
by means of an inwardly projected unitary shank
drill, router bit, or reamer, whereby a cutting
25. A nut 26 having an inner tapered face is
or grinding operation may be performed on such
shown at 2‘! and serves upon tightening upon
workpiece along any corresponding helical edge
threads 28 of the chuck body to wedge the col
variable combination of simultaneous rotation and
or path having any desired pitch.
These and other objects and features of nov
let jaws 2ll into gripping position upon the ‘cy
lindrical shank 29 of the tool to be machined.
The inner end of the tubular spindle l4 within
the housing If! carries a thrust bearing iii] which
35
lustrate preferred embodiments of the invention.
comprises an inner cylindrical race 3! and outer
Figure 1 is a perspective view of the general
cylindrical race 32 and intermediate needle bear
arrangement of the apparatus of the invention
ings as shown at 33. At either end of the inner
elty will be evident hereinafter in the description
which, together with the following drawings, il
in operative position.
and outer races 31 and 32 thrust washers as
Figure 2 is an end cross-sectional view taken
shown at 34 and 35 are provided which abut at
4:0
online 2-—2 of Figure 3.
one end against a collar 36 formed integral with
Figure 3 is a cross-sectional side elevation of
the spindle and at the other end against an ad
the machine taken on line 3-3 of Figure 2.
justable stop nut 31 which is in turn carried on
Figure 4 is a cross-sectional detail of the chuck
the inner threaded end of the tubular spindle.
ing unit carried by the apparatus of Figure 3.
A look nut 38 is provided for retaining. the
Figure 5 is a cross-sectional View taken on line 45 thrust nut 31 in adjustment.
'
5—-5 of Figure '2.
The spindle drive shaft [5 which telescopes into
Figure 6 is a detail view of the stop plate taken
the bore of the spindle M is rotatably supported
on line 6-—6 of Figure 3.
in a bushing Ml which is retained in a suitable
Referring now to the drawings in which like
opening in the end of the housing iii in coaxial
reference characters refer to corresponding parts
throughout the several ?gures, the apparatus of
the invention is as follows:
A housing In is provided for enclosing the major
elements of the machine, said housing having ‘a
removable top i I normally held in place by means
of a pair of machine screws i2 and I3.
Extending lengthwise through the upper por
tion of the housing is a composite shaft com
prising tubular spindle M and a coaxially posi
tioned spindle drive shaft l5, said tubular Slim
alignment with respect to the beiorementioned
bearing holder l9 and bushing l8.
As herein
before stated the drive shaft [5 is of such a size
as to make a snug sliding ?t within the bore M
of the tubular spindle I4, whereby said tubular
spindle may be reciprocated With respect to said
drive shaft through bushing iii. .A spur gear 48
is keyed at 42 to the drive shaft I 5 adjacent the
inner surface of the rear end of the housing. A
hub member 43 is keyed at 44 and retained in
2,408,916
3
adjusted axial position on the outer exposed end
of the drive shaft I5 by means of a set screw 45.
The inner ?ared end 48 of the bushing .40 acting
against the hub of the gear £8 and the washer 41
acting intermediate the housing and the adja
cent surface of the hub 53 serves to restrain the
spindle drive shaft against axial movement with
respect to the housing.
4
within a corresponding slot as shown at 04
formed in the lower surface of the housing or
outer race 32 of the needle thrust bearing 30.
The nut 80 and the needle bearing housing 32
are thus secured against rotation.
The lead screw nut 80 is provided with a pair
of coaxial oppositely extending trunnions as best
shown at 85 and 86 in Figure 2 and the needle
. An operating lever or handle 50 extends radi
thrust bearing housing 32 is similarly provided
ally from the hub 43, said handle comprising an 10 with a pair of coaxial oppositely extending trun
inner shaft 5I and an outer axially movable tu
nions as shown at 81 and 88. The trunnions 85
bular slide 52. The inner handle shaft 5I is ?xed
and 86 of the lead screw nut are each pivotally
in radially extending position with respect to the
carried in square cross-head members ‘I9 and 88
hub 43 by means of threads and lock-nut as
and the trunnions 81 and 88 of the needle thrust
shown at 53 and 54 respectively.
15 bearing housing 32 are similarly pivotally carried
The tubular handle slide 52 is slidable or re
in square cross-head members 90 and BI.
ciprocatable upon the handle shaft 5| within the
A pair of oppositely positioned walking beam
limits set by the stop nut 64 against the force of
members 92 and 93 are pivotally supported at a
the helical spring 55. The helical spring 55 act
point intermediate their ends by means of a pair
ing under compression normally retains the tu 20 of pins or bolts as shown at 95 and 96 which are
bular handle shaft in a maximum outward po
in turn carried in the inwardly extending ends of
sition against the stop nut 64 on the end of the
a pair of adjustable supporting arms 91 and 98.
handle shaft whereby an offset latch member 56
Each of the walking beams is provided with a pair
carried at the lower end thereof and movable
of elongated slots or slides as best shown at I00
radially in a slot 56' in the hub 43 will normally 25 and IOI in Figure 5. The inner longitudinal sur
be retained in locked position within a radial
faces of the slots I00 and If“ serve as guides in
locking groove 63 which is formed in the rim 5‘!
which during the operation cross-head members
of a circular stop plate 58 which is in turn ad
90-—9I and 19-89 slide.
justably supported from the outer face of the
The arms 9‘! and 98 are movably supported
rear end of the housing by means of a pair of 30 upon a cross-shaft I02 to which they are keyed
suitable machine screws as shown at 58 and 50.
as shown at I03. The cross-shaft I02 is pivotally
A pair of semi-circular slots 61 and 82 as best
supported in a pair of oppositely positioned
shown in Figure 6 provide for angular adjust
bushings I05 and I06 located within the side walls
ment of the stop plate for suitable angular posi
of the housing. The cross-shaft I02 is adapted
tioning of the lock groove 63 as desired.
35 to be adjustably rotated by means of a lever I01
Enclosed within the lower portion of the hous
which carries at its outer end a pointer I08 adapt
ing I0 is a lead screw shaft 65 rotatably sup
ed to move over a graduated scale I09 carried on
ported with its axis parallel with the axes of the
a scale plate H0. The adjustment lever I0"! ‘is
before described tubular spindle and drive shaft,
adapted to be ?rmly retained in a given adjust
in bushings 66 and 61 which are in turn re 40 ed position with respect to the scale I 09 by means
tained in the walls of the housing by means of
of a knurled nob III the shaft of which extends
the bearing holders 63 and 69. A spur gear 10
through the outer end portion of the lever as
meshing with the beforementioned drive shaft
spur gear 48 is keyed to the lead screw shaft as
shown at ‘H and adjustable to a limited degree
axially thereon by means of a set screw 72. A
collar or abutment 13 is formed integrally with
the lead screw shaft and axial motion or play of
the lead screw and the lead screw shaft 55 is
limited by the abutment of the said collar 13
against the inner ?ared end 14 of the forward
bushing 66 and the contact of the hub of the
spur gear 10 with the inner surface of the inner
?ared end 15 of the rear bushing 61.
The lead screw shaft 65 carries at an interme
diate section and formed integral therewith a
ground and polished lead screw having a plu
rality of threads of suitable pitch as shown at
‘l6.v A nut 00 having internal threads is threaded
on the lead screw '26 and is adapted to axial
movement upon rotation of the lead screw shaft
65 as hereinafter more fully described.
As an
example, a %—6, 60° stub tooth lead screw hav
ing a major diameter of approximately .875 inch,
a minor diameter of .724 inch, a pitch diameter
of approximately .80 inch, and a lead of T55 inch
was satisfactorily employed in a machine of the
type illustrated. The mating nut 80 is provided
shown at II 2, and makes threaded connection
with a threaded nut which moves in an arc in
an internal arcuate recess II3 formed on the
inside face of the scale plate H0.
Angular displacement of the adjustment lever
I051 serves to move the adjustment arm 91
through a corresponding angle which in turn,
acting through the pins or bolts 95 and 96, serves
to shift the walking beam 92 longitudinally with
respect to the cross-heads 19-89, 90——9l.
A flexible leather boot II5 ?xed to the spindle
?ange 22 by means of a clamping wire I I6 and
retained in rotatable ?t in an annular groove II‘!
in the outer end of the bearing holder I9 by
means of a snap ring H8 serves to prevent for
eign matter from entering the bearing surfaces
between the spindle shaft I 4 and the bushing l8
which at the same time provides for rotational
and reciprocative freedom of the spindle shaft
with respect to the apparatus housing I0.
The operation of the apparatus is as follows:
The drill reamer, router-bit, or the like tool
which it is desired to sharpen, is inserted into the
collet chuck as best shown in Figures 1 and 4.
The rotating cutting wheel I20 powered by suit
able means such as an electric motor, not shown,
with an upwardly extending elongated guide
is adjusted into position where, for example as
tongue 8I. The guide tongue‘SI is solidly ?xed 70 illustrated in Figure 1, a router bit is to be sharp
within a slot 82 formed in the upper side of the
said nut 80 and is held therein by means of
three countersunk machine screws as shown at
83. The upper, elongated portion of the guide
tongue enters and makes an axially sliding ?t 75
ened, the cutting edge IZI will make proper con
tact at the proper angle with the cutter blade I 22.
The lever I0‘I is then adjusted to raise or lower
the position of the walking beams 92 and 93 so
as to vary the length of the lever arms L1 and La
2,408,916
formed by the said walking beams 92 and 93
between the pivotal center of the walking beam
supports 95 and st and the centers of the cross
heads e?~9i at the spindle thrust bearing and
5
tion by means of the latch tongue 56 extending
into the locking groove 63 formed radially in the
circular rim 5'! of the stop plate. Upon depress
ing the handle slide 52 radially inward against
the force of the spring 55, the latch tongue 56 is
cross-heads ‘l9 and 89 at the lead screw nut so
that the cutter will, in effect, follow exactly the
carried inwardly out of engagement with the
groove 63, thus freeing the handle for rotation
spiral or helix described by the cutter blade I22.
of the spindle drive shaft iii. In operations where
The ratio of the axial motion of the tubular spin
a larger number of the same kind of tool is to be
dle with respect to the axial movement of the
machined or ground, it may be desirable to ad
10
lead screw nut will always be proportional to the
just the angular position of the stop plate by
ratio of the length of the lever arm L1 to the
means of the screws 59 and E9 to provide for
length of the lever arm L2. Axial motion of the
identical and suitable initial settings of the ma
spindle it and the chuck carried thereon is thus
chine in accordance with the working require
e?ected by means of the opposite axial motion
ments.
15
of the lead screw nut til, acting through the two
While a grinding wheel, for purposes of illus
oppositely positioned walking beams 92 and 93.
tration, has been shown at I20 in Figure 1, other
Adjustment of the height or vertical position of
the walking beam by angular adjustment of the
types of cutting tools may obviously be employed
to perform similar operations.
arm 9'! is thus obviously effective to vary the
While a preferred embodiment of the inven
ratio of the motion of the spindle with respect 20 tion has been illustrated and described hereinbe
to the motion of the lead screw nut between cer
fore, the invention is not to be limited thereby,
tain limits determined by the dimensions of the
but is intended to cover any variation or modi?
elements of the machine, particularly the walk
cation Which falls within the scope of the claims.
ing beams s2 and 93.
_
I claim:
Upon rotation of the spindle drive shaft l5 25
1. Apparatus for machining a helical surface
by means of the handle 52, the lead screw shaft
comprising chucking means for a workpiece to be
55 will also be rotated in an opposite direction
machined, a coaxial shaft rotatably and axially
through the action of the mutually meshing spur
reciprocatably supporting said chucking means,
gears t8 and ‘Hi. Accordingly, if the handle 52
a lead screw positioned parallel to and adjacent
30
is rotated clockwise, the drive shaft it‘: will like
said shaft, drive means coupling said lead screw
wise be rotated clockwise and the lead screw shaft
'and said shaft together for simultaneous rotation
85 will be simultaneously rotated counterclock
at a fixed ratio, a nut on said screw axially mov
wise at a speed which is proportional to the ratio
able in response to rotation of said lead screw, a
of the number of teeth on the spur gear 68 to the
thrust
bearing associated with and adapted to
number of teeth on the spur gear '38. Rotation 35 move said chucking means axially, a walking
lead
screw
shaft
65
and
the
beam pivotally coupled adjacent one end to said
7 thus imparted to the
lead screw ‘56 formed thereon will simultaneously
nut and adjacent the opposite end to said thrust
result in axial motion of the lead screw nut 89
bearing, means to support pivotally said walking
to the left as viewed in Figure 3. The motion
beam for angular displacement in response to
thus imparted from the nut 86! to the crossheads 40 axial motion of said nut whereby said thrust
‘i9 and 89 contained within the lower slot ID!
bearing and said nut are thus coupled together
of the walking beams 92 and 93 will result in
through said walking beam for simultaneous ax
counter-clockwise angular displacement of the
ial motions.
said walking beams about the centers of their
2. Apparatus for machining a helical surface
supporting pins 9'5 and 93 with resultant axial 45 comprising chucking means for a workpiece to be
motion of the cross-heads so and 91 to the right,
machined, a coaxial shaft rotatably and axially
as viewed in Figures 3 and 5. Corresponding ax
reciprocatably supporting said chucking means,
ial displacement of the spindle thrust bearing to
a lead screw positioned parallel to and adjacent
the left will result in an outward extension of the
said shaft, drive means coupling said lead screw
tubular spindle shaft iii. The spindle shaft will 50 and said shaft together for simultaneous rotation
thus have imparted to it a simultaneous clock
wise rotation and axial translation, the relation
ship of one to the other of which will depend
upon the beforementioned gear ratios between
at a ?xed ratio, a nut on said screw axially mov
able in response to rotation of said lead screw, a
thrust bearing associated with and adapted to
move said chucking means axially, a walking
the gears iii and ‘IE1 and the ratios of the lever 55 beam pivotally coupled at one point thereon to
arms L1 and L2. By computation or by experi
said nut and at another point thereon to said
ment, proper adjustment of the adjustment arm
thrust bearing, means to support pivotally said
9? and the corresponding position of the lever
walking beam for angular displacement in re
it‘? may be determined for any given relationship
sponse to axial motion of said nut whereby said
between the angular rotation of the spindle shaft 60 thrust bearing and said nut are thus coupled to
and its simultaneous axial motion. Thus any
gether through said walking beam for simultane
desired motion of the tool to be machined corre
ous axial displacement.
sponding to any desired pitch or spiral can be
3. Apparatus in accordance with claim 1 in
obtained. When such relationship has been com
which said pivotal walking beam support is ad
65
puted or otherwise determined, the plate I I0 may
justable in position with respect to said pivotal
be calibrated by the placing thereon of a corre
‘ coupling to said nut and said thrust bearing.
sponding scale as shown at I09, whereby pre-ad
ll. Apparatus according to claim 2 in which said
justrnents of the machine may be readily made
pivotal walking beam support is adjustable in po
by simply setting the pointer Hi8 upon the proper 70 sition with respect to said pivotal coupling to said
marking of the dial I69.
As hereinbeforementioned, the lever arm 50 is
normally locked in ?xed position against rota
nut and said thrust bearing,
_
,
ANDRE CROT.
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