An Improved Method of Grinding and Polishing Glass by Means of Grindstones.
Year: 1899

page_text: Date of Application, 2nd Oct., 1899
Complete Specification Left, 16th Feb., 1900-Accepted, 7th Apr., 1900
PROVISIONAL SPECIFICATION.
An Improved Method of Grinding and Polishing Glass by Means of
Grindstones.
I, DÉSIRÉ GILLES, of No. 17, Rue Wéry, Brussels, in the Kingdom of Belgium,
Engineer, do hereby declare the nature of this invention to be as follows:-
My invention has for its object a new method of polishing glass plates
designed to replace the existing mechanical and manual methods.
My said invention consists essentially in subjecting the glass to be polished
to the action of a series of rotatory horizontal grindstones which successively
effect the levelling of its surface, and its smoothing and polishing.
For a long time past use has been made of grindstones for the bevilling of
glass plates but these grindstones act vertically that is to say by their sharp
edge and only so as to work upon and polish the part being bevilled, whereas
my method is based on the use of grindstones acting horizontally that is to
say by their plane surface and arranged in such manner as to effect all the
operations necessary in the polishing of the glass plates.
My invention is particularly applicable to the polishing of thin glass plates
and the width of which does rot exceed the diameter which can be practically
given to the grindstones but my said invention may also be applied to the
polishing of glass plates of great width by employing an arrangement permitting
either the grindstones to be moved in the direction of the width of the glass
plates or the glass plates to be moved under the grindstones transversely or
laterally as well as longitudinally.
For putting my said method into execution I employ by preference one or
two sets of three grindstones arranged in series, each grindstone being supported,
in such a manner as to be capable of rising and descending a short distance,
at the lower end of a vertical shaft connected to driving mechanism which
communicates to it a rotary motion.
Each set of grindstones comprises a levelling stone and a smoothing stone
of emery, carborandum or other suitable material having the grain required for
the work to be effected and a third grindstone for effecting the polishing.
Upon rails fixed below the grindstones are supported and slide movable
tables on which the glass plates to be polished are secured.
The movable table carrying the rough glass plate is first advanced until the
edge of the glass plate is under the edge of the first or levelling grindstone.
A slight rotatory movement is then communicated to the said stone through
the medium of its vertical supporting shaft and the stone is lowered until it
bites well on the edge of the upper face of the glass plate; the rotatory motion
of the grindstone is then accelerated while the table and
the glass
plate supported by it are advanced until the glass plate has passed
entirely under the stone. The same operation is then repeated with the

page_text: two other grindstones by which the polishing of the glass plate on one of its
sides or faces is completed. If the apparatus comprises two sets of grindstones
the glass plate is then returned in order to pass it under the second set and
polish its other face or if there be but one set of grindstones the glass plate is
again passed under them after it has been returned.
My method of polishing by the aid of grindstones presents great advantage
in the manufacture of lenses.".
-
For this purpose I employ grindstones the acting faces of which have the
required concavity or convexity and the mode of working differs from that
herein before described only in the respects that the lens to be polished has to be
brought entirely under the grindstone before the latter is put in action and
that the lens remains motionless during the whole operation of the grindstone.
Instead of using grindstones of emery or analogous matter for the levelling
and smoothing or second grinding use may be made of grindstones of sand-
stone or of cast iron covered with coarse sand, or carborandum or pulverized
emery but this mode of working is far from presenting the advantages of the
method herein before described.
It is evident that for the polishing of plates of glass having plane surfaces,
the rotatory grindstones might be replaced by plates of the same matter,
having a horizontal transverse motion imparted to them.
Dated this Second day of October 1899.
W. T. WHITEMAN,
Agent for the Applicant.
COMPLETE SPECIFICATION.
An Improved Method of Grinding and Polishing Glass by Means of
Grindstones.
I, DÉSIRÉ GILLES, of No. 17, Rue Wéry, Brussels, in the Kingdom of Belgium,
Engineer, do hereby declare the nature of this invention and in what manner
the same is to be performed to be particularly described and ascertained in
and by the following statement:-
My invention has for its object a new method of polishing glass plates
designed to replace the existing mechanical and manual methods.
My said invention consists essentially, in subjecting the glass to be polished
to the action of a series of rotatory horizontal grindstones which successively
effect the levelling of its surface, and its smoothing and polishing.
For a long time past use has been made of grindstones for the bevilling of
glass plates but these grindstones act vertically that is to say by their sharp
edge and only so as to work upon and polish the part being bevilled, whereas
my method is based on the use of grindstones acting horizontally that is to
say by their plane surface and arranged in such manner as to effect all the
operations necessary in the polishing of the glass plates.
My invention is particularly applicable to the polishing of thin glass plates
and the width of which does not exceed the diameter which can be practically
given to the grindstones but my said invention may also be applied to the
polishing of glass plates of great width by employing an arrangement permitting
either the grindstones to be moved in the direction of the width of the glass
plates or the glass plates to be moved under the grindstones transversely or
laterally as well as longitudinally.
In order that my invention may be readily and clearly understood, I will

page_text: now describe it with reference to the accompanying drawings in which is
represented, by way of example, an apparatus adapted for polishing plates of
glass the width of which does not exceed the diameter of the grindstones
employed.
In the accompanying drawings.
Figure 1 is a front elevation of one of the grindstones of the apparatus
partly in section taken upon line C-D of Figure 2.
Figure 2 is a plan view of the same in section upon line A-B of Figure 1.
Figure 3 is a diagrammatic view illustrating in plan upon a smaller scale,
the assemblage of tables and grindstones which constitute a complete apparatus,
and
Figure 4 is a detail view upon a larger scale, showing a means of adjusting
the tables.
The apparatus preferably comprises two series, each consisting of three
grindstones a, a, a, each of which is carried by a vertical shaft mounted in
bearings arranged in cross-pieces e passing between uprights d.
These shafts are connected with suitable driving mechanism, (which is not
represented in the drawing), which imparts to them movement of rotation.
Brackets e fixed inside the uprights below the grindstone, support rails f
which extend from one end of the apparatus to the other. Upon these rails f
rest and slide the displaceable tables y upon which are secured the pieces of
glass to be polished. In order to ensure that the tables shall be perfectly
horizontal, the rails f may be supported in the brackets e by adjusting screws h
which pass through the brackets, as shown more clearly in Figure 4.
The tables may be provided with lateral edges or flanges i Figure 4 in order
to retain the waste arising from wear of the grindstones. These tables are
adapted to be displaced either by hand, or by means of an endless screw engaging
in a screw-threaded aperture 1.
Each series of grindstones comprises a grinding stone a, a smoothing stone a¹
of emery, carborandum, or other suitable material having an appropriate grain
for the work to be effected, and a third stone a² which constitutes the buffing
disc.
The grindstones are provided with a metal casing j furnished with an inter-
nally screw-threaded central socket adapted to connect them with the sup-
porting shafts b, the lower part of which latter is screw-threaded in order that
it may be engaged in the said socket. A set screw m is provided for the purpose
of adjusting the grindstone at any desired height.
The operation of the apparatus is as follows: The glass in the rough which
it is desired to polish having been secured to the table g, this latter is advanced
until the glass is brought against the grinding stone a to which is imparted
a movement of rotation which is but slight in the first place, whilst the operative
after having unscrewed the set screw m, lowers the grindstone upon the shaft b
by causing it to rotate in the proper direction by hand. When the grindstone
engages or bites" the upper surface of the glass to a sufficient extent, the
set screw m, is tightened the movement of rotation of the shaft bis accelerated
and the table displaced until the whole of its surface has passed beneath the
grindstone; it is then advanced to the edge of the smoothing stone a¹ where
the same operation is repeated, and finally it is moved into contact with the
buffing or polishing disc a².
When the piece of glass has passed beneath the three stones a, a, a², it is
polished upon one of its faces. It is then removed from the table, and turned
in order that its other face may undergo the same treatment by being passed
successively beneath the three stones a, a, a² of the second series. Whilst this
is taking place a fresh piece of glass in the rough state may be submitted to
the action of the first series of stones.
Instead of two series of stones, it is obvious that the apparatus may consist

page_text: of one set only, and in this case the glass will of course be passed twice beneath
the same set of grindstones in order to polish both its faces.
The employment of grindstones for polishing presents great advantages in
the manufacture of lenses.
In such cases, instead of employing grindstones having plane surfaces, grind-
stones having faces of the desired degree of convexity or concavity are used,
and the operation only differs from that above described owing to the fact
that the lens is brought completely beneath the grindstone before this latter
is caused to rotate, whilst the lens remains motionless throughout the operation
of the grindstone.
Instead of employing stones of emery or similar material for grinding and
smoothing, grindstones of sandstone or cast iron discs with coarse sand or pul-
verised carborandum or emery may be used, but this method of operation is
far from presenting the same advantages as that above described.
In the same way that there are several devices for polishing plates of glass
by means of powdered or granulated substances, the grindstones or masses which
I have described may be employed in various manners. As for example instead
of being suspended above the plates of glass to be polished, the grindstones
may rest upon rotary tables, whilst the plates are secured beneath movable
discs arranged above the grindstones. Or if desired the rotary grindstones may
be replaced by discs of similar material to which is imparted a transverse
rectilinear movement and which are arranged either above or below the plates
of glass to be polished.
It is
The invention may be easily applied to existing glass grinding machines by
fitting a number of grindstones to the underside of the upper frame.
also applicable for the bevilling of glass plates as well be easily understood.
The method of polishing above described is equally applicable for polishing
other hard substances such as marble, porcelain, metals and the like.
I do not limit myself to the method of carrying my invention into practice
as above described, which is given by way of example only, but may modify
the arrangement of parts in various ways without departing from the spirit of
my invention.
Having now particularly described and ascertained the nature of my said
invention and in what manner the same is to be performed I declare that what
I claim is:
1. A method of polishing plates of glass and similar substances, consisting
in submitting the surface to be polished to the action of grindstones acting by
means of their plane surfaces, substantially as above described.
2. A method of polishing plates of glass, consisting in submitting the piece
of glass to be polished successively to the action of a series of grindstones
rotating horizontally and acting by means of their plane surfaces, such grind-
stones or discs being composed of materials adapted for effecting successively
the grinding, smoothing and polishing of the glass, substantially as above
described.
3. A method of polishing glass described in Claim 1, consisting in securing
the piece of glass to be polished upon a movable table sliding in rails passing
beneath the polishing discs, or the like, which are mounted in such a manner
as to be capable of being raised and lowered upon vertical shafts arranged in
cross-pieces passing between uprights, to which shafts a movement of rotation
is imparted in any suitable manner, substantially as above described, and repre-
sented in the accompanying drawings.
4. The application of the method described in Claim 1 to the polishing of
lenses by means of grindstones the operative face of which has a convexity or
concavity corresponding to the form which it is desired that the finished lens
should have, substantially as above described.

page_text: 5. The application to the upper frame of existing glass grinding machines.
of grindstones acting by means of their plane surfaces substantially as above
described.
Dated thie Sistoanth day of February 1900
W. T. WHITEMAN,
Agent for the Applicant.