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Патент USA US2404184

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July '16, 1946.
W. LUDEL‘, '
4 2,404,184
Filed June 28, 1944
‘ Willzlzm lamb'el.
Patented July 16, 1946
_ 2,404,184 _
William Ludel, New York, N. Y.
“Application June 28,1944, Serial No. 542,525
‘ 3 Claims.
(01. 125-39)
This invention relates toan abrasive wheel
selves in a more efficient abrading position, espe#
cially under heat treatment tending to effect’
dressing tool, more ‘particularly to an abrasive
wheel dressing tool employingv diamonds as the
wheel dressing abrading material and to a method
for preparing the same, >
ebullition of the alloy.
Still more particularly I have discovered that
with diamonds of a size within speci?ed ranges
and of octahedron shape, an ebullition of the
matrix alloy free from exterior in?uences tending
‘. ,
Known to me is the provision of tools employing
diamonds for dressing grinding wheels where
these. are made of .Carborundum or like material
to otherwise stir up the liquid mass, causes the
particles of diamond of octahedron shape to ad-_
in which the abrasive particles of this constitu
tion are united by some bond or binder and are
just themselves, prior to setting of the alloying
matrix, to produce a highly ef?cient wheel dress
formed vo1- cast into wheels, ‘When these wheels
become scored or otherwise irregularly worn, they
ing tool.
are ‘,‘dresscd’,’ by a dressing tool, as known in the
art, in which a toolcarrying a harder material
Accordingly, it is an object of my invention to
provide‘ a wheel dressing tool employing diamond
than, the-abrasive of the wheel is employed to 15 crystals held in a wheel tool by a metallic matrix
refinish the surface.
to dispose the crystals of diamondsto provide a
7 There has been devised, as known to me, dress
highly‘ efficient wheel dressing surface or mass,
ing tools'comprisinga rod-like member formed
Still further it is an object of my invention‘ to
at one end with a‘ cup or socket within which dia
provide a method for forming a wheel dressing
mond'dust or diamond fragments are held by a 20 tool in which diamond‘ crystals are embedded in.
matrix of alloy. The cup or socket is ?lled either
a metallic matrix under conditions which will
bypouring. the mixture of molten metal and the
permit the diamond crystals to arrange them- '
diamond dust into the cup or socket, or by mold
selves freely and assume positions within the
ing a'mixture of the diamond dust and pulverized
matrix most effective for wheel dressing opera
alloying material to form, under sintering tem 25 tions, ‘unaltered by the means to heat the matrix
peratures, a bond for the diamond dust particles,
metal, and uninhibited to move to have the crys
thereby providing a formed abrasive material by
tals assume the most effective cutting position by
the combined action of heat and pressure. These
contact with adjacent crystals.
dressing tools have not met with success due to
Thus, it is an object of my invention to pro
an ine?icient use of the diamond dust or parti
vide a tool holder with a cup or socket for ex
cles. Use of these‘ tools has resulted in glazing
of the dressing tool surface, tending to favor the
use of a single large diamond for the dressing
operation and more frequently employing a clus
ter of a small number of diamonds in some me
chanical holder to effect the wheel dressing oper
posing a wheel dressing surface or end, in which
diamond crystals are held within a matrix of
metallic alloy in which the particles assume the
most effective cutting position by freedom of
35. movement within the matrix alloy by melting the
alloy, before cooling,.to an extremely liquid con
The prior procedureknown to me involving a
Still further objects of my invention reside in
pouring of a mixture of alloying material and
the provision of a wheel dressing tool which is
diamond dust or particles or the molding process
highly efficient in its wheel dressing action,
is not efficient-because of the haphazard arrange
To obtain these objects and such further ob
ment of the diamond dust, the failure to take into
jects as may appear herein or may be hereinafter
account the weakness-of diamond fragments and
pointed out, I‘make reference to the accompany
the reliance merely upon the characteristic hard
ing drawing forming a part hereof in which:
ness of the diamond dust or fragments in relation 4.5,,
Figure 1 is a side elevation partly in section
to the abrasive of the wheel to be dressed.
diagrammatically illustrating the apparatus for '
I have ‘discovered that within limited and
forming my wheel dressing tool;
rather‘ critical sizes of diamond crystals of octa
Figure 2 is a magni?ed fragmentary section of
hedron shape and alloying material, which will
hereafter be described more particularly, and
which may be heatedto secure a free-?owing, ex
tremely ~liquid~ material, that a more efficient
wheel dressing tool may be made than heretofore.
the working end thereof;
Figure 3 is a plan view of the working end of
my wheel dressing tool; and
Figure 4 is an end elevation showing the tool
applied for grinding wheel dressing operations.
In accordance with my invention, by reference
shape inan, alloyat the liquid stage adjust them- up to the drawing, I provide a tool holder bodyllil
I have discovered that diamonds of octahedron
Handy 8a Harmon, and is known on» the market
which is preferably a rod of cold rolled steel of
under the trade-mark “Sil-Fos."
su?icient length to serve for manual holding or
tool rest mounting, one end of which is restricted
at l l and formed with a socket or cup I2, de?ned
by a chamfered portion l3 at its periphery. The
. .
This is an alloy which consists of silver, varying
from 10% to 25%, copper from 67% to 88%, and
phosphorus varying from 2% to about 8%.‘, The
alloy starts to melt at about 1,185“ F. (641° C.)
and is extremely liquid and free-?owing at 1,300°
restricted portion H is then disposed within the
high frequency induction heating elements I 4
and I5, the terminals of which, l6 and H, are
formed with conductors i8 and I9 to a suitable
F. (704° C.) to 1,340° F. (727° 0.).
v _
At temperatures somewhat higher than 1,340"
source of electricity to provide high frequency 10 F. (‘727° 0.) there is evidence of ebullition, which
is to be noted in connection with my process in
current suitable for inducing su?icient heat to
of its phases. The characteristic features of
convert the matrix alloy to extreme ?uidity with
the alloy described in relation to the diamond
inthe socket I2 of the tool holder body It. In
crystals resides in the extreme fluidity and free
this position I then insert a strip or ?lament of
alloying material 20, which, at the temperature of 15 ?owing character of the alloy at the tempera
tures induced by the induction heater and the
evidence at higher temperatures of ebullition.
small portion thereof to provide a layer 2| of
Extraneous disturbing in?uences are avoided by ,
molten alloying metal. Thereupon the strip of.
the induction heating method which I have de
metal 20 is removed and there is added to the
socket l2 a few crystals of diamond particles 22. 20 scribed, which, by reason of the method of adding
the diamond crystals in their relatively sparse
Thereupon the strip of alloying material 25} is
condition'andf the fluidity of the alloy‘, serves'to
reinserted within the socket l2 to provide another
permit the particles tov assume a position during
layer of molten material. Another layer of dia
heating to dispose and position the sharper points
mond crystals 23 are then sprinkled within the
socket. 'This procedure is continued to supply 25 26 in the direction of the working edge l3 as the
tool'holder body I0 is held ‘vertically’ during the
alternating layers of the alloying metal in mol
heating operation‘. The pyramidal ‘side walls of
ten form followed by a sprinkled layer 24 of
the induction heating apparatus, serves to melt a
diamond crystals until the socket it has been
?lled, such as by providing another or super
~imposed layer of diamond» crystals 2 5.
the diamond crystals are likewise effective as the
diamonds wear down in the wheel dressing op
eration as shown in Figure 4 Where the tool I0
Thereupon-‘the induction heating element is
is pressed against the periphery ofthe grinding
brought into play to bring the alloying metal to
extreme ?uidity to the point where there is evi~
dence-of ebullition. During this operation the
Upon: cooling of the tool and its contents, the
alloy matrix retains the diamond crystals in the
diamond crystals are free to move and in in
wheel W.
stances show evidence of rising and falling within the lique?ed alloy. During this action the par
" 'ticles adjust themselves to position the effective
cutting edges 25 in the direction of the rim 13.
most effective position described. This effect is
sharply in contrast with methodsv heretofore
knownto me, involving either the‘ pouring of a
molten alloy and diamond particles‘ to Within the‘
tool holder cavity, a molding mixture of the dia
mond'alloy and sintering of the matrix alloy, or
A rather sparse supply of diamond crystals, to 40 a setting of the diamonds in a matrix binder alloy.
_ the point where .there is ‘sufficient space for free
and independent adjustment of the crystals in
relation to ‘the lique?ed alloy matrix, is one of
the desirable phases of my procedure whereby
Freedom of movement’ of the particles in the
matrix alloy in the?uid condition contributes to
the‘ adjustment‘ of the particles, to‘ achieve the
most desirable and effective direction and is not
the crystals may adjust themselves and assume 45 to be confused with a heating of a matrix alloy
the most desirable position for the wheel dress
which merely ?lls and flows into the interstices
ing operation.
In the practice of my invention, I have dis
of a socket ?lled with diamond dust or particles.
By the use of the induction heater which I, have
covered that diamonds in the crystalling form 50 described ‘and preferably employ,v alteration by
and of substantially true octahedron shape, pro
oxidation of the‘ alloying material, is substantially
vicle the most desirable result and these crystals
avoided. The formation of an oxidized coating
are carefully selected from diamonds as mined
is likewise not experienced which, in accordance
to be free from fracture or. chips and are there
with prior‘ methods‘, I believe, inhibits the free
fore distinguishable from diamond dust or chip 55 movement of the particles to their most effective
abrading? position.
pings, ?akes, or the like, which are by-products
of the diamond industry in connection with bril
While, from‘my experience, the Sil-Fos alloy
lianteering or polishing diamonds for their or
has been found to give the‘ most satisfactory re
namental and optical properties. In connection
sults, it is clear that other alloys may vsuggest
with atool holder which exposes a working sur-v 60 themselves to those‘ skilled in the art from some
face adjacent the periphery ll? of approximately
of the comparable properties during the heating
three eighths of an inch in diameter, I have
operation which I have described by reference to
Si'l-Fos. However, I have found that the silver-_
found that in relation to the particular alloy
which Iv will describe hereafter, that selected dia
mond crystals of octahedron shape and of the
' size approximately 25 to 35 to the carat, prefer
ably 30 per carat, best serve my purposes. Chips
and ?akes are to be avoided. . Sizes of crystals
much above 25 to the carat or much below 35 to -
copper-phosphorus alloy’ which I employ addi
tionally responds desirably during the wheel
dressing operation, in that there is a kind of soft- ‘
ness in'the matrix formed by this alloy which
results‘ in doing clean work without gathering
detritus as‘ a result of the wheel dressing opera
the carat do not respond favorablywithrthe alloy 70 tion, and therefore, with the matrixalloy which
Iemploy, the effectiveness of the wheel dressing
I will now describe.
operation is not limited, but does clean cutting
The alloy which I have found as having a
7 specific relationship to the diamond crystals of
the size as described, is an alloy made under the
patent to Leach, Patent No... 1,829,903, assigned to w
of ‘the wheel to be dressed to vthe last layer of
the diamond crystals in the socket [2 as the side
walls i i‘ are worn down in the ?nishing-‘operation. '
I maintain the induction heater in operation
during the building up of the batch within the
socket I 2 and my method of maintaining a liquid
condition of the matrix alloy as each layer of
diamond crystals is added avoids any tendency
to fracture the diamond, such as is known to re
sult by successive heating and cooling of the
matrix alloy to embed diamond dust or crystals
in wheel dressing tools by a procedure amounting
to setting of the diamonds in the alloy and in 10
tive cutting points of .the octahedron crystals in
the direction of the working surface by a ?ota
tion of the crystals in the matrix during the
heating operation by the induction heater and
this orientation is aided to some extent by the
ebullition during the ?nal heating steps of the
?lled socket after the successive layers of molten
alloy and crystals have been built up to fill the
Accordingly, I have provided a wheel dressing
tool comprising a plurality of diamond crystals
oriented with their most effective cutting edges
volving building up layers of alloying material,
then setting diamond dust therein by removing
the source of heat, followed by alternate steps of
in the direction of a working surface of the. wheel
adding an additional layer of alloy and diamond
dressing tool and held therein in an alloying
dust. Each step of removing the heat by this 15 matrix. Other advantages will readily appear to
process known to me has a deleterious effect on
those skilled in the art. '
the diamonds due to shrinkage and expansion of
Having thus described my invention and illus
the heated alloy.
trated its use, what I claim as new and desire
The number of diamonds employed within the
to secure by Letters Patent is:
socket is dependent upon the size of the wheel 20
1. The method of making a wheel dressing tool
dressing tool and the particles are limited sub
in which a plurality of diamond crystals are
stantially to provide the degree of sparseness and
bonded by an alloy matrix within a form, the
spacing of the crystals in relation to each other
steps which include providing said form with a
whereby free movement is permitted to effect the
charge of diamond crystals and an alloy con
adjustment of the crystals within the ?uid alloy 25 sisting of silver varying from about 10% to 25%,
matrix during heating operation.
copper varying from about 67% to about 88%,
The diamond crystals to be employed are those
and phosphorus varying from about 2% to about
Which are free from extraneous minerals on the
8%, the diamonds being sparsely distributed, and
surfaces thereof. Mechanical cleaning may be
said alloy with the diamond‘ crystals
resorted to, though frequently dipping in acids 30 heating
in situ to the point where the alloy becomes
to remove extraneous matter is found to be prac
highly liquid and free-?owing to the point of
ticed by the suppliers and is found to be desirable.
?uidity, permitting the crystals to adjust them
While this special treatment is practiced, it is to
selves in the liquid alloy independently of each
be understood that cleanliness to insure direct
then cooling the mixture in the form.
contact of the alloy with the diamond crystal is 85 2. 'A and
wheel dressing tool comprising a body por
the object to be attained by the cleaning process.
tion having a socket at one end ?lled with a
By my method, whereby diamond crystals or
mixture of diamond crystals and a matrix alloy,
grains of octahedron shape within the range of
the diamond crystals being sparsely disposed and
sizes between 25 to 35 to the carat, preferably 30
independently oriented in the direction of the
to the carat, an unpredictable relationship to the 40 mouth of the socket, said diamond crystals being
preferred alloy, which I have described, exists,
approximately 30 to the carat and the alloy
in that the crystals assume a desirable position
matrix consisting of silver varying from about
in relation to the working surface and are not
10% to 25%, copper varying from about 67%
subject to any differential and detrimental shrink
to about 88%, and phosphorus varying from
age force in cooling of the alloy until the ?nal
about 2% to about 8%.
mass has been formed and the ?nishing tool is
3. A wheel dressing tool comprising a body
free from any evidence of inadequate surface con
portion having a socket at one end ?lled with
tact between the matrix and the diamond crystals.
a mixture of diamond crystals and a fused matrix
Furthermore, by the use of the alloy con
alloy, the diamond crystals being sparsely and
stituent for the matrix as herein described, a fast 50 independently oriented in the direction of the
grinding wheel ?nishing operation is exhibited
by my ?nishing tool, free from any tendency to
gather detritus limiting the cleaning-up action
mouth of the socket, said diamond crystals being
of a size varying from about 25 to 35 to the
carat and the alloy matrix consisting of silver,
of the dressing tool in its action upon the grind
varying from about 10 to 25%, copper varying
ing wheel.
55 from about 67 to 88%, and phosphorus varying
While I do not wish to be restricted to the
from about 2 to 8%.
following explanation, the procedure described
shows evidence of orientation of the most effec
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