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Патент USA US2411709

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Nov. 26,v 1946.
2,411,709 y
Filed Aug. 19, 1944
.#ffi ß.`
u’ _
FIP/»15.57 A. BROWN.
Byß _
Patented Nov. 2.6, 1946
, 2,411,109
Ernest A. Brown, Elyria, Ohio
Application August 19. 1944,' serial No. 550,151
A1 '
This invention relatesbroadly to grinding fix
-tures and more specifically to mechanism for
controlling the oscillatory movement of drills and
similar tools while forming the lip angle .and
land margin clearances therein.
»having the cam therein for the development 'of
the lip clearance in the tools; and
. .
Fig. 8 is a view in perspective ofthe fixture and
fragmentary portion~ vof a grinding machine, the
illustration showing the operative relation of the
ñxture, the tool or work piece, andthe grinding
One of the objects of the invention is to pro
vide a fixture for dressing or re-working end
`Referring first to Figs. 2 and 3, the fixture
cutting tools of the type used in screw machines,
comprises a rectangular block I0 machinedwith
to form'combination drills, counterbores or center
longitudinal kerf II in one side thereof and
drills therefrom, the fixture being designed to 10 ia'
throughout its length for the reception of
produce the proper lip clearance angle, land mar
I2 _and I3 and rotatable, centrallyV dis
gin and land clearance in each stepped portion
posed sleeve I 4. Thepsplit portion of the block
Another object of the yinvention is to provide ' is drilled and tapped to receive set screws I‘l which
`:are provided'to accommodate the clamped're'ten. a drillholder which >is designed to facilitate >pro
tion ofthe bushings within'the'block. The block
duction of land margins `oi? Various widths.'
is further drilled and tapped _for'set screws I5
Another object of the invention is to construct
which are .preferably formed with cylindrical vends
a fixture having demountable bushings therein
I8 adapted for engagement in openings in the
which are mounted for ready removal to accom
modate substitutive bushings of different size.
Another object of the invention is to provide
a drill supporting ñxturewhich is- adapted to de
velop relief ycontours ' of uniform' configuration
_ .
bushings and provided to prevent longitudinal
movement thereof.
' The side wall of the sleeve I4 is drilled toure
ceive a: pin I9 that protrudes` inwardly in _the
bore and Vis coni'lg'uredß for' slidingïengagement
and proper form when used by unskilled or inex
25 within the flute of the cutter supported there
perienced operators..
in. Portions of- the end walls of the sleeve are
Further objects ofthe »invention reside in the
.machined to' form slots 20 and 2| fory the re
provision of a fixture whichis economic/ofmanu
ception of the end portions of thumb screws 22
facture, sturdy ofgstructure and susceptible of
and 23 mounted in the block IU. The slots are de
use on grinding machines of various forms..
30, signed to. permit limited rotative movement of
Other objects and advantages ymore or less
the tool while grinding the land clearance and to
ancillary to the foregoing and the manner in
arrest such movement and initiate a helical move
which all the various objects are realized will ap'
pear in the following description, which con
Ament of the tool through the action of the pin
I'9 when the grinding Wheel reaches> the point
sidered in connection with the accompanying 35 that deñnes the width of the land margin. ' One
drawing, sets forth the preferred embodiment of y
of the slots is formed a few thousandths of an
inch longer than the other in order to facili
tate the production of landsV of different width,
either the screw 22 or 23 being engaged within
Fig. l is a view in perspective of the improved 40 the proper slot during such operation. When a
tool dressing fixture including a drill shown in
tool or similar helical fluted cutter is rotated with
in the fixture the pin I9 will cause the rotation o1'
its assembled relation therein;
Fig. 2 is a longitudinal section through the ñX
the sleeve until the shoulder of the slottherein is
the invention. .
Referring to the drawing wherein the preferred
embodiment of the invention is illustrated:
ture shown in Fig. 1;
brought into engagement with the thumb screw.
Fig’ 3 is a transverse Sectio-n taken on a' plane 45 Whereupon .the sleeve will cease to _rotate and
the tool will be moved in the helical-path of the
indicated by the line 3-3 in Fig. 2;
flute leaving a land margin M (Fig. 4) of the
Fig. 4 is a transverse section through the lix-V
desired width and of the diameter obtained in a
ture illustrated in Fig. 1; _'
preliminary circle grinding operation. The end
Fig. 5 is a longitudinal section through the fix
ture showing in dotted lines a helical fluted drill 50 wall of .the outer bushing I3 is formed with a cam
24 having a lift 25 of sufficient height to develop
in place;
the lip clearance angle desired in the tool for
' Fig. 6 is a View in perspective of the sleeve ,em
which the bushing is designed, for example, the
ployed to control the development of the land
angle A in the drill shown in Fig. 5. The rise
clearance and land margin in the tool; the bushing 55 2B of the cam'is equal to the width of the land
Fig. 7 is a View in perspective of
clearance in such a tool, for example, the dimen
sion B in Fig. 7.
ting tools comprising a block having a bore
therein extended throughout the length thereof,
The block l0 may be clamped upon the platen
bushings in said bore for the support of the tool
to be ground, a collar adapted for securement
of vthe grinding machine or mounted with the base
30 thereof upon the face of magnetic chuck of
the type customarily used in such environs. In
setting up the fixture the block is adjusted rela
tive to the grinding Wheel so that the medial
axis of the ltool to be ground Will lie in a plane
on the shank of the tool, a cam in the end Wall
of one of said bushings configured to advance
the tool in the pattern of the lip clearance when
the tool is rotated With the collar engaged with
said cam, a sleeve rotatable Within said bore
common to the vertical axis ofy the grinding Wheel
spindle and _Wirthlthe end portion of the tco1~en-
_ having an4 elongatedopening therein, a pin in
gaged with" the 'circumferential face of the wheel.
In forming the stepped shoulders on the tool,
the feed may be effected by raising the knee 'of
the machine and reciprocating the platenpjn the. _
customary manner.
__ movement thereof for grinding the land margin
rsaid block disposed forïengagenient within the
opening in the sleeve to delimit the rotative
‘ and a second pin in the sleeve arranged for en
_@_gagelnenti with the flutes in the tool to elîect
A collar 21 bored for engagement` with-the" ‘» ,_ the >helical movement thereof for grinding the
shank of the tool to be dressed _is providedfto; ef~
lland clearance.
fect the lineal translation vof the tool during the '
lip clearance grinding operation.
The-«collar» or -
follower is locked upon the tool with set screws
`28 mounted ony thebodythereofi the, endlfwall
‘ofthe’ collar being formed Vwith lugs >>.ZSljdesigned
`forengagement"fWithÍthe cam 2A.y The rake or
clearance, land and land clearance in helical
Vfiuted drills comprising a rectangular block bored
throughout its length, bushings in each end
ïf thereof »for- ‘guidin'gïf-land l su
pporting :a "i-drill,
:cam in `the 'end-'Wall`4 of one’ o'f""»th'e bushingsl a
jlip y clearance 'is gforìned by ñr-st mounting». the
:'.collar engageable With"'the"dril1 andï's'aid'v camjto
tivefto’thë grindingl Wheel lto 7the vpoint Yangleof
a sleeve havingza slot iri- tl'ie‘leridfwall thereó'f'iìn
:saidv block,r alfpin '-inïthe îborev of said sleeve" and
kcollar "2,1 riporijtiie'` m01', 'adjùstmg the bloei; 'reia- 1 25v.facilitate grinding'îthe lip clearanceîin thiel‘drijll,
‘the tool, rètractingthe thumb screws Z‘Z _and ,23
«means in; said'A block to 'delimit-'the 'rotative mov’e
tg facilitate ther free rotation of the troolnwithin
x* the vbushings YI 2 and Ä I3, bringing ‘the-‘_lip; _of-„the
;‘Lment of saidvîsleevelil-
i> vcol''intofc'onta‘ct „With ;the grinding _ WheeLf then f
a.: 3.1Af grinding fixture for iiuted 4drills com
jjv'vnileçnoiqing j‘th'ejmgîgc into _ Contact Winn 1_the
_fcamn'iß'vljbtating .andf simultaneously feeding ythe
$901." ir'ïtotlie _grinding„,wheel until> the__.¿stockfis
_ground 'away to `thefiill length `of the , point. f
_1_"Ifhe, _foregoing Íp'rocedure -comprehends the
-operations -re?ll'iired in- grinding, the -`lip, ; clearance
and land margin in end lcutting tools of the „usual
form.'> f _Iny `redressingV or reworkingv tools _ of
4stepped`diam1ete`rs such, for example, as combina
tion or center drills, vas used in `screw machines,
the several shouldered'steps inthe dríllsare first
circled _ground to size, then each .Steppin turn is
grounded to the proper point angle, lip clearance,
land‘margin. and land clearance inthe manner
described above._
'íï‘ ï»
prisingra block having a' borë`~`the?ein,
unta‘bly` sup
on the free end of one of said bushings, ï‘co'l'l'ars
.for each size ."drill‘demóuntablyf-fsupported`- on
bore iintermediatef said ïbushlngs; al pin-"in 'said
fsleeve adapted‘rfor engagement 'with the filut'e „in
-the drill being 'groundffafpin irï‘said 'bloclgfar
ranged 'for reentra'nt ~-engagement 'inî the- bore-¿of
said block, and Íshoulders‘inl'l'sai sleeve engage
able with theaiastflnainea 'pin te’
ta-tive ^' m'oveme'ntvuthe’r'eofi »Y
QA. A; grin-dirigí fixture f for helical f_luted tools,
comprising a block- having'a hole‘ther'e'infor‘th'e
„Although the foregoing description is neces
reception of the tool, bushings@inßfthëgopposed
ends‘of said hole, 'a' cam on-Ttlïè éndîvír‘all
sarily of a` detailed character, in. order'that the
of said bushingsvto guide 'the-frodi ‘inward-1y and
inventioninay be completely setlforth, it is to be
understood that thexsrpeciñc terminology is._not f 'outwardly in ai'he'lical path,`a èollarf-adapte‘dïor
engagement ’With-»said calmT and for'rclyem‘ountable
intended to be__re'str1ctive.or confining, and that
various >rearrangements of parts and modiñca- ` securem'entï on lthel-ït'òolgfA a 'sleeve"'mountëd“'for
tions o_f detail _may `_beresorted to -without vde
vrotative movement'inïfsaid hole, fmeans t‘ö‘delimit
parting .from the scope4 or. spirit of the invention
the‘rotation "thereof, and means/in l'saidÃsleeve
to elïect ‘ the helical Smove'íne'ntfof "saïidïî tool after
herein claimed, "_ _
`theyrotative movement offîthe ¿sleeveî hasJ
"1. A_ grinding fixture for helical fluted cut
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