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Патент USA US2128591

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Aug. 30, 1938.
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w. H. MCGILL
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TOOL SHARPENING ÃPPARATUS
2,128,591
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Filed Jan. 5', 1936" `
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/N VENTO
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Patented Aug. 30, 1938
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AUNITED STATES PATENT O-FFQIQE .
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2,128,591
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.TOOL SHARPENING APPARATUS
-William H. ’.McGill, Winchester,.Mass.
:Application January 3, 1936, Serial No. 57,375
solaims. (o1. 51-158)
This invention relates to apparatus for facili- a guiding plate 5. Preferably .this plate is made
tating. the hand sharpening >of -edged tools, such of hardened steel, although this is not always
as. chisels, gouges, blades, and others: ofthe type necessary. When the apparatus is in use the>
in which it is importantto have the edge ground plate 5 is stationary, but it is mounted for Verti
or sharpened to a uniform or .other predetercal adjustment relatively to the stone, this 5
UI mined bevel.
mounting comprising a cup-shaped member 6,
Various devices designed to accomplish this ob- V of relatively short Vertical dimensions, but .pro
ject have been proposed heretofore but those of vided with a screw threaded shank 1 supported in
which I have been able to learn have been of an internally threaded bushing .8 withv which
10' such a nature as to- restrict >or hamper the movements required in performing certain of 'these
hand sharpening operations. Such movements
includenot only free movements of the tool'over
the ibase 2 is equipped. By fitting ‘the threads 10
tightly . suiñcient friction is provided between
these >parts to hold the plate against accidental
change of adjustment, while still Y'permitting the
the stone while its edge is held .in contact vwith
l5 the grinding surface, .but also freedom to pick
up the tool at any instantto examine itsedge.
To devise an apparatus of ‘lthe- generalfcharacter above> designated -«which=will 'avoid the objections just described, constitutes‘the` chief ob-
part 6 :to be
Assuming
hand plane
in .a holder
20 ject of the present invention.
screw I3 threaded through the upper arm ofthe 20
_
The nature of the invention willbe readily
understood from the'followingdescription when
read in connection with the accompanying-drawing, and the novel features V.will be particularly
mi pointed out inthe appended claims.
In the drawing, '
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Figure l is a perspectiveview, 4with some -parts
3o
yoke and-provided above said arm with athumb
piece lll land below it with a foot l5 .adapted to
bear on the shank portion of the blade or other
tool l0. .By tipping the tool and the yoke, one
relatively to the other,’untíl the two edges of 25
theblade l0 are in contact withthe opposite ver-v
broken away,¿ofan apparatus constructed ‘in fac-
tical arms of the yoke, the blade will'be `centered
in the holder. Then by turning down‘the screw
cordance with this invention;
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Fig. 2 is a plan View of i' the apparatus‘illustrated in Fig. ’1;
Fig. 3 is a vertical, sectional View through a
I4 the blade can be securely clamped against the
base piece of the holder.
30
Projecting from the lower side of the yoke l2 .
is .an .arm t6, .rigid with the `part |12, and hav
portion of the base and the guide plate mounted
thereon, showing the DI‘OViSîOIl fOr adjustment
ing a ball I'l‘mounted in its lower extremity. The
walls of the socket in‘which the ball is supported
:l5 of the latter relatively to the base;
Fig. 4 is a sectional View through the tool
holder; and
Fig. '5 is a lfront` elevation of a diiîerent 'form
of _holder designed for use in -sharpening gouges.
.lo
Referring flI'SÈ t0 Figs. 1 and-2,' the «apparatus
there shown comprises a’baSe 2 ‘Whiehìmey C011ifeniently be made 0f castfiron 0.1.’ any other Suitable material. In the upper Si‘d’e Of-'ßhìS base a
socket 3 is provided ‘to ‘I‘eCeiVe La gl'îïldStOIle 01’
u equivalent Sharpening deVîCe‘Ãl FOI’ many» Pul‘poses it is desirable to use la circular stone, >as
ShOWïl, and 'G0 have-011e Side 0f the :S’ßOne 0f a
Coarse, fast-Cutting material, While the Opposite
side is of a much finer-»grained and slower cut-v
m'- ting composition. `~For >this purpose ~the socketv
31preferably is :made l.somewhat ‘larger inv diameter than the stonefsok thatfthe latter 'can conveniently be 'lifted out Vof .,it, freversed and -replaced.
_mi
revolved to raise or lower it.
that the tool to be sharpened is a 15
blade IU, such a blade is mounted
I2 comprising a yoke-shaped body
member provided with a slot through‘which the
blade may be slipped freely, and a clamping
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At one Side of the‘stone'A-.thebase y2 supports
are so crimped overthat they retain the ball ef- 35
fectively, while at the same time >permitting the
ball to revolve freely around its own center.
When the blade'has been secured in the holder,
as above described, the assembly is positioned
as illustrated in Figs. 1 and 2 with the beveled 40
edge of the blade resting on the upper surface
of the stone a and the bau a1 riding on the non»
zontal surface of the plate 5. The .workman then
moves the blade over the .surface ofthe stone,V
exactly as'hewould in hand sharpening without 45
the aid 0f any guiding device. such movements
usually include a somewhat circular motion of
the blade on the stone, the edge of the tool be
ing moved over practically the entire face of the
stone as the sharpening operation progresses so 50
that >the vstone will .be kept level and localized
wear will be substantially avoided. During all
of these movements the -angle of the blade due
the stone remains constant and unvarying due
to the fact that this angle is determined :by the 55
2
2,128,591
distance between the blade and the surface of
the ball I1 at its point of contact With the plate
5.
This
distance remains
constant
notwith
standing the movement of the blade over the
stone. Thus the workman is relieved of the dif
ñcult operation of maintaining the blade con
tinuously at the same angle, which is absolutely
essential in order to grind the edge to a uniform
bevel.
Adjustment of the angle of the tool on the
face of the stone 4 can be made by changing the
relative elevation of the stone and the guiding
plate 5, or the length of the arm I6. Preferably,
however, this is accomplished by the screw mount
ing of the plate, as above described, and as shown
in Fig. 3. It will readily be observed that if the
plate is revolved toward the right, Fig. l, it will
be lowered, thus tending to grind the heel of
the bevel more rapidly,- whereas if the plate is
revolved in the opposite direction the blade will
be tipped up so that more of the grinding opera
tion Will be conñned to the extreme edge of the
blade.
Attention is directed to the fact that the only
contact between the holder and the guide plate 5
is one of surface engagement, the ball moving
freely over the upper surface of the plate in any
direction as the sharpening operation progresses.
This is important for the reason that as said
operation proceeds, thevworkman lifts the blade
Ill from time to time and examines its edge to
see whether or not the bevel is correct, and
whether the edge is sharp enough. Toward the
completion of this operation he will test the edge
on his thumb, or in any other way to which he
is accustomed. If he finds that the bevel is not
right, he will make suitable adjustment to correct
the difficulty. If the edge is still dull he will
continue with the sharpening operation until
finally he has produced the condition which he
desires. However, the fact that he can lift the
blade off the stone at any time and handle it
exactly as he would if the holder were not on it,
and replace it again instantly without disturbing
any adjustment, is an important practical ad
vantage.
In other words, this apparatus requires
no change in the hand sharpening practice or
method but it gives the workman the advantage
of maintaining the correctl bevel constantly with
out effort on his part.
At the same time the
workman can perform the sharpening operation
more rapidly, both because of maintaining the
exact bevel continuously and also for the reason
that greater power and pressure can be applied,
especially in the roughing operation.
In order to prevent the lower ball end of the
guide member I 6 from running ofi" the edge of the
guide plate 5, the holder in which this plate is
mounted preferably is provided with an upright
, arm or margin I8, closely surrounding the plate
and projecting above it. The outer cylindrical
surface of this member may be knurled, as shown
in Fig. 1, in order to facilitate the rotation of this
holder in making the adjustment above described.
When the sharpening operation has been com
pleted the screw I3 is backed up, thus releasing
the blade Il) and permitting the workman to
withdraw it from the holder. When-ever a blade
is inserted and centered in the manner above de
scribed, the greater part, if not all, of this lcen
tering operation will be performed automatically
by the twisting of the blade in the holder as the
clamping screw I3 is tightened up. This same
operation centers the blade with reference to the
75 guiding arm I 6.
Such a holder as that illustrated in Figs. 1, 2
and 4 can be used with a great variety of edged
tools.
Some tools, however, and some blades will
require a special form of holder. One such form
is illustrated at 2U in Fig, 5, this holder being
Il
designed for use in sharpening gouges. The
shank of the gouge 2I is supported on the tapered
walls of the body portion of the holder, and it is
clamped against them by a screw 22. In sharp
ening a gouge, however, a transverse rocking
movement of the tool on the stone is necessary in
order to present different portions of the curved
edge of the tool to the stone. At the same time
the angular relationship of the tool to the stone
should be maintained in order to produce a uni
form bevel. This result may be conveniently ac
complished by equipping the holder with a tem
plet 23, the lower edge of which has the same
transverse curvature as the gouge. The edge of
this member can be both moved over the plate 5
in any direction and also rocked on this plate as
the sharpening operation progresses, thus enabl
ing Vthe Workman to grind the entire edge to the
correct bevel but relieving him of the effort and
skill required to hold the tool continuously in the
correct angular relationship to the stone. The
yternplet 23 may consist of a thin plate inserted
in a saw cut or slot in the holder 20 and clamped
securely, but removably, by a screw 24.
While I have herein shown and described a 30
typical embodiment of my invention, it will be
evidentthat the invention may be embodied in
other forms without departing from the spirit
or scope thereof.
k
Having thus described my invention, what I de
sire to claim as new is:
35
1. In a tool sharpening apparatus, the combi
nation of a flat, relatively stationary- grindstone,
a tool holder comprising a yoke-shaped body
member, a Ábase piece connecting the arms of 40
said member, a screw carried by said yoke for
engagement withthe base piece to clamp the tool
securely butv releasably in the holder for the
sharpening operation, a guide plate, a support for
holding said stone and said plate positioned hori
zontally and closely adjacent to each other, said
tool holder including an arm rigid therewith and
in axial alinement with said screw and having a
round ended guiding member at its lower end
arranged to bear on the upper face of said plate
and freely movable in any direction on said face,
50
said member cooperating with said plate and
said holder to determine the angle at which said
tool will be held on the surface of said stone
while the tool is moved over the stone, and means
for preventing the movement of said guiding
member off the edge of the plate.
2. In a tool sharpening apparatus, the com
bination of a flat, relatively stationary grind
stone, a base having a socket therein to receive 60
said stone and to support the same in a hori
zontal position, said socket and stone being con
structed to permit the angular adjustment of the
stone into a series of different positions therein
whereby the wear on the stone may be distrib
uted more uniformly, a horizontal guide plate 65
mounted on said base closely adjacent to said
stone, a tool holder constructed to clamp the tool
to be sharpened securely but releasably therein
for the sharpening operation, said tool holder 70
including a guiding member arranged to bear on
the upper face of said plate and freely movable
in any direction on said face, said member co
operating with said plate and said holder to de
termine the angle at which said tool will be held
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2,128,591 l
on the surface of said stone while the tool is
moved over the stone, and means adjustable to
change the angular relationship of said tool to
the grinding face of said stone.
3. In a tool sharpening apparatus, the combi
nation of a flat, relatively stationary grindstone>
of circular outline, a base having a circular
socket therein to receive said stone and to sup
port the same horizontally for rotative adjust
ment in said socket, a tool holder constructed to
clamp the tool to be sharpened securely but re
leasably therein for the sharpening operation, a
horizontal guide plate mounted on said base
adjacent to said socket, said tool holder includingV
15 a guiding member arranged to bear on the upper
face of said plate and freely movable in any
direction on said face, said member cooperating
with said plate and said holder to determine the
angle at which said tool will be held on the sur
20 face of said stone while the tool is moved over the
stone, and means adjustable to change the angu
lar relationship of said tool to the grinding face
of said stone.
4. In a tool sharpening apparatus of the char
acter
described, a grindstone, a guide plate, a sup
25
port for the stone and plate, a yoke~shaped tool
holder having a slot therethrough for the recep
tion of the shank of the tool, said slot having end
and bottom walls and being wider than said
30 shank and permitting lateral movement of the
shank in the holder, said movement being limited
by the end walls of said slot, a clamping screw
threaded through the upper wall of the yoke
shaped portion of the holder for exerting pres
sure on said tool perpendicular to said plane of
lateral movement to clamp said tool in said slot
against said lower Wall, an arm rigid with said
yoke-shaped portion and extending therefrom
in axial alinement with said screw, and said arm
having an end face curved about a center lying lO
in said axis and adapted to bear on said guideplate.
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5. In a tool sharpening apparatus, the combi
nation of a flat, relatively stationary grindstone,
a base having a socket therein to receive said 15
stone and to support the same in a horizontal
plane, said socket and stone being constructed to
permit the angular adjustment of the stone in
said horizontal plane into a seriesy of different
positions therein whereby the wear on the stone 20
may be distributed more uniformly, a horizontal
guide plate over which the tool is guided during
the sharpening thereof mounted on said base
closely adjacent to said stone, screw threaded
means supporting said plate for adjustment verti 25
cally relatively to said stone, and a tool holder
provided with a guide arm adapted to rest upon
and move freely over the surface of the guide
plate.
WILLIAM H. MCGILL.
30
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