An Improved Method of and Apparatus for Grinding Glass.
Year: 1892

page_text: Date of Application, 5th Oct., 1892-Accepted, 5th Nov., 1892
COMPLETE SPECIFICATION.
An Improved Method of and Apparatus for Grinding Glass.
I, JAMES WILLIAM BONTA of Wayne, Delaware County, in the State of
Pennsylvania, United States of America, Engineer, do hereby declare the nature
of the said invention and in what manner the same is to be performed, to be
particularly described and ascertained in and by the following statement :-
The object of my invention is to provide means for reversing plate and sheet
glass in a grinding machine so as to grind both surfaces of the glass as fully
described hereinafter.
In the accompanying drawings:
Fig. 1, is a side view showing the grinding bed of a grinding machine with the
mechanism for reversing the plate of glass, the grinding mechanism being omitted
to avoid complication.
Fig. 2, is a side view similar to that shown in Fig. 1, but showing the plate
clamped between the two platens ready to be lifted and reversed.
Fig. 3, is-a sectional plan view on the line 1-2, Fig. 1.
Fig. 4, is a sectional plan view on the line 3-4, Fig. 1,—and,
Fig. 5, is a transverse sectional view showing the glass clamped between the two
platens and in the act of being reversed.
Heretofore, in the manufacture of glass, especially plate glass, the glass is usually
in very large sheets, and when placed on the bed or platen of the grinding machine
has to be handled very carefully in order to prevent it from cracking or breaking,
and when turned so as to expose the opposite face after one face is ground, it has
to be handled with the greatest care, by a number of men, to prevent it from
sagging and breaking, and a great percentage of the glass broken is broken during
the grinding and during the adjusting of the plate to the grinding platen or bed,
therefore, the main object of my invention is to handle the glass in a perfectly safe
manner and to dispense with the extra help heretofore needed, as by my invention
one man can readily manipulate the glass.
Referring to the drawings, A, is the base of the machine having a central shaft a,
provided with a pocket a', to receive the post b, of the platen B, upon which the
glass x, rests. The platen is in the present instance also supported by antifriction
rollers c, arranged in suitable bearings on the base of the machine.
The shaft a, has a bevel gear wheel a', meshing with the bevel wheel a³, on a
shaft a', mounted in bearings in the base of the machine, and provided with a belt
pulley. This shaft is the driving shaft for turning the platen under the grinders,
which are omitted to avoid confusion, as any suitable grinders may be used without
departing from my invention.
D, represents two standards connected together at their upper ends by the cross
bar D'. These standards are slotted, and adapted to slide in these slots are
frames E, carrying the pivots e, upon which the platens are turned as fully described
hereinafter.
At each side of the platen B, are bearings 61, for the pivot pins e, and resting
upon the pins as shown in Fig. 1, is a second platen B', having bearings b³, and a
post b, similar to the post of the platen B.
The sliding frames E, are raised and lowered by mechanism which I will describe
hereinafter.
On one of the pivot pin carriers is a turning wheel G, by which the two platens
are turned to reverse the plate of glass. The wheel has in the present instance
two pins which pass between the platens so that any rotary motion given to the
wheel will be imparted to the platens.
Before describing the mechanism by which the pivots are raised and lowered, I

page_text: will describe the operation of as much of the machine as I have noted above, as it
will be understood that any suitable mechanism may be used for raising and
lowering the platens.
The glass, is placed on the lower platen B, in any suitable manner, the platen
being removable, it can be detached from the grinding machine if necessary and
receive the glass at the most convenient point, and then placed upon the machine.
After one side of the glass has been ground the slides carrying the pivot pin on
which is mounted the platen B', are lowered from the position shown in Fig. 1, to
the position shown in Fig. 2, and when the second platen B', rests upon the glass
the two platens B, B¹, are secured together in any suitable manner, in the present
instance I have shown hooks c', but it may be necessary to use clamping bolts
which will accommodate the different thicknesses of the glass.
After the platens are secured together with the glass between them they are
raised to the position shown by dotted lines in Fig. 2, and then turned by the hand
wheel G, as shown in Fig. 5, so as to reverse the sheet of glass and the platens,
the platen B', becoming the under platen. The two platens are then lowered to the
position shown by full lines in Fig. 2, and uncoupled, the slides E, are then raised
to the position. shown in Fig. 1, exposing the unground surface of the glass to the
grinders, thus the sheet of glass is reversed without the liability of its being broken,
the whole operation being done very quickly and by the single attendant who has
charge of the grinding machine.
In place of the hand-wheel shown I may turn the platens from one of the power
driven shafts of the machine through intervening gearing and clutching mechanism.
I will now describe the mechanism by which the platens are raised and lowered.
Adapted to each slide E, is a vertical screw rod h, having at its upper end a bevel
wheel, meshing with a bevel wheel h³, on the shaft H. This shaft is provided
with a belt pulley and is driven from any power shaft so that on turning the shaft H,
the slides E, will be raised and lowered according to the direction in which the
shaft H, is turned.
The shaft H, is mounted in suitable bearings on the cross bar D', and the screw
rods are also adapted to bearings in said cross rod.
In order to securely lock the two platens B, B¹, to the pivot pins, I provide
laterally adjustable sleeves n, shown clearly in Fig. 3, which can be forced out over
the bearing 6', 63, as clearly shown in Fig. 2, thus forming a lock in addition to the
hooks. These sleeves are forced out by mechanism which I will now describe.
On the slides E, are two vertical shafts N, one on each slide, on the lower end of
each shaft is a cam n', adapted to a cam plate n³, which extends through and is
guided in the bearing N'. This cam plate n³ snugly fits the sleeve N, so that any
transverse motion given to the cam plate by the cam will move the sleeve in or out
as shown by dotted lines in Fig. 3.
At the upper end of each shaft is a gear wheel t, meshing with the teeth p, of a
rack bar P. This rack bar is moved by a lever T, pivoted to the rack bar at q, and
to a link u, which in turn is pivoted to one of the slides E, so that by moving the
lever T, from the position shown in Fig. 1, to the position shown in Fig. 2, the cams
are turned and the sleeves forced out over the bearings of the two platens, firmly
locking the platens together.
Having now particularly described and ascertained the nature of the said inven-
tion, and in what manner the same is to be performed, I declare that what I
claim is :-
1. The process herein described of grinding plates of glass, said process consisting
in first mounting the plate upon a platen or bed, then grinding the upper face of said
plate, then clamping the plate between its supporting platens, and a second superposd
platen, then turning the platens with the plate between them so as to reverse the
plate, then removing the top platen, and finally grinding the surface of the plate
which is now uppermost, substantially as specified.
2. The combination in a grinding machine, of the mechanism for rotating the glass

page_text: under the grinders, a platen adapted to said mechanism, and on which the glass to
be ground is mounted, a second platen also adapted to the rotating mechanism,
means for securing the two platens together, and means for reversing the platens
with the glass between them, substantially as specified.
3. The combination of the two platens adapted to clamp the glass between them,
mechanism for rotating the platen carrying the glass beneath the grinders, bearings
on each of said platens, pivots adapted to said bearings, and vertically adjustable
frames carrying said pivots, substantially as described.
4. The combination of the two platens, mechanism for rotating the lower platen
when in position, bearings on each of said platens, vertically movable slides carrying
pivot pins adapted to the bearings, sleeves extending over said bearings, and
mechanism for advancing and withdrawing said sleeves, substantially as described.
5. The combination of the two platens, the slides E, pivot pins on said slides to
which the platens are adapted, vertical screw rods adapted to said slides, and a
driving shaft geared to both of said screw rods, substantially as described.
6. The combination of the two platens, two slides, pivot pins on said slides adapted
to bearings on the platens, mechanism for raising and lowering said slides, sleeves on
each slide capable of being moved over the bearings of the platens, vertical cam
shafts carried by the slides, cams on said shafts adapted to move the sleeves, pinions
on said shafts, with a rack bar engaging said pinions, and mechanism for moving
said rack bar, substantially as described.
Dated this 5th day of October 1892.
DAY, DAVIES & HUNT,
321, High Holborn, London, W.C., Agents for the Applicant.