Improved Process and Machine for Grinding and Polishing Glass, more particularly Plate Glass.
Year: 1892

page_text: Date of Application, 23rd May, 1892-Accepted, 25th June, 1892
COMPLETE SPECIFICATION.
Improved Process and Machine for Grinding and Polishing Glass,
more particularly Plate Glass.
A communication by ROBERT FRIEDEL, of 10, Sennefelderstrasse, Stuttgart, in
the Empire of Germany.
I, WILLIAM PHILLIPS THOMPSON, F.C.S., M.I.M.E. of the Agency for Foreign
Patent Solicitors, 6 Lord Street Liverpool and 6, Bank Street, Manchester, both in
the County of Lancaster and 323 High Holborn, in the County of Middlesex, Civil
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 :-
The invention hereinafter more particularly described relates to a new process for
grinding more particularly rough glass, as well as to the machine for carrying out
this process.
The grinding processes hitherto employed consist either in the grinding stone
being slid backwards and forwards over the plate glass, or in the use of a number
of flat rotating round grindstones with a level grinding side which are moved over
the surface of the glass. The first named process still at present the one most
usually employed, but it requires an extremely long time before the glass plates are
ground even tolerably even, the other method works somewhat quicker but not to
such an extent that the saving in the cost of manufacture can be said to be any
considerable one.
The improved process, which unites with perfect work a capability of enormous
delivery, the result of which is a very low cost of manufacture, consists essentially
in placing the glass plates on a travelling carriage (resembling an iron planing
machine) and operating on the upper side of the same by means of a number of
rotating polishing rollers, placed one behind the other, the latter being further
given an axial backward and forward sliding motion.
The glass plate may also have a continuous progressive motion, as shown in the
form of apparatus represented in the drawing, but the various grinding stones may
also be moved continuously in a straight line over the glass plate. The polishing
rollers may each be separately adjusted to each side of the support as well as
collectively raised aloft, in such a way that the contact of each grinding roller with
the glass plate may be exactly regulated. The grinding rollers are further so
arranged that they may be horizontally adjusted parallel to their point of suspension,
that is to say that their centres may be placed at a greater or less distance in a
horizontal direction from their points of suspension. The pressure of the rollers on
the glass plate is thereby increased or diminished. The spring pressure of the
rollers is further so regulated that the springs may be more or less compressed.
On the accompanying drawing, one method of carrying out this process is shown.
Figure 1 represents a cross section,
Figure 2 a longitudinal section, and
Figure 3 a plan view of the rough glass grinding machine, whilst
Figures 4 and 5, which are drawn to a larger scale, show the method of adjusting
the grinding rollers in the oscillating frame.
The polishing or grinding roller W which is made of emery, stone, cast iron or
other material suitable for grinding glass, or the axis w of the same, is carried, by
means of the support A' which may be adjusted by means of the hand wheel a¹, in
the loosely suspended frame A, the axis a of which rests in bearings revolving on
two supports Z Z. These latter are suspended by means of screws zz to two fixed
holders Z Z and may be collectively adjusted vertically by means of the hand-

page_text: wheel D actuating any suitable gearing, so that with grinding glass plates of
varying thicknesses it will not be necessary to adjust each separate grinding
roller W.
The axial sideways adjustment of the grinding rollers W is effected by means of
a crank or gearing through worm k and spurwheel K, or in other suitable manner
on each separate oscillating frame A, and oscillating with the same by means of the
transferance of the motion of the eccentric or crank, through the rod h¹ and elbow
lever h² to the axis w of the grinding roller.
The glass plate is laid on a carriage F, provided with a thin covering of india-
rubber or other suitable material, and is firmly fastened sideways by means of the
lower corners to the edges of the same. The carriage F travelling on two rails E,
in the same manner as a planing machine, is moved forward by means of a rotary
spindle e.
In order to render possible a continuous working of all the various grinding
rollers W, that is to say, in order that it may not be necessary for the carriage
to be always returned when a glass plate has passed through, devices for lifting the
carriage Fin and out are arranged at both ends of the rails E, and, further, as is
however usual in lathes, the nut of the carriage F which engages in the spindle e is
made detachable. The lifting of the carriage F into or out of the slide rails E is
effected by means of two rails G which are arranged on 4 cranks g' in such a way
that they may be raised or lowered by turning the lever g, and in the first case rest
under the runners f, and cause the lifting of the carriage which can then be carried
away together with the glass plate on a wagon or in any other suitable manner.
If a number of carriages F be employed, they may run directly one after another
in such a way that the various grinding rollers work continuously, and in this case
each carriage must only be lifted in and out before or after the grinding respectively.
The pressure of the rollers W is brought about in a double manner, namely, by their
own weight, as well as by means of springs f" acting on the rollers, the tension of
which, and thereby also the pressure of the same inay be regulated.
For regulating the pressure caused by the weight of the rollers themselves, set
screws attached to the support C are employed by means of which the horizontal
distance of the centre of the grinding rollers from the vertical centre d of the part
from which they are suspended may be adjusted Further, the supports C are so
arranged as to be themselves horizontally adjustable on the frame B.
For regulating the spring pressure of the rollers W, pins c' are arranged in the
support and can revolve at one end, whilst the other end of these pins slides in
slots of the contact strips which are attached to the oscillating frame A. An
adjustable ring is placed over these pins c', and between this and the contact
strip, a spring is arranged, the tension of which may be regulated by the
adjustment of the above named ring. Each grinding roller W has thereby at a
given place a constant adjustable and a changing adjustable pressure which both
increase with increasing oscillation.
The grinding rollers are actuated by means of belts from the oscillating shaft a.
The rails E are arranged on the frames B and B¹ by means of cross bars b. The
method of driving the spindle e is not particularly indicated in the drawing; it is
performed however in such a way that the forward movement of the carriage F
may be varied.
In the arrangement shown in the drawing as an example of this improved grinding
process, four grinding rollers W arranged one behind the other. are employed, that
is to say, this machine is only arranged for the grinding of plate glass. Polishing
rollers may however be arranged directly behind the grinding ones and working in
a similar manner thereto, so that grinding and polishing may be carried out in
one operation.
If required any suitable number of grinding or polishing rollers may be employed
for grinding or polishing.
Instead of the collective vertical adjustment of the grinding rollers W, which has

page_text: for its object to allow of glass plates of various thicknesses being ground without
adjusting the rollers singly, the carriage F may be made vertically adjustable by
arranging the slide rails E so as to be vertically adjustable.
The oscillating suspended grinding rollers W may also be utilised for grinding
long straight edged facets. The glass plates are in this case laid on a level table and
the grinding rollers W are arranged somewhat deeper in such a way that the
facets will be steeper or not so steep, according as the rollers are arranged more or
less deep.
Having now particularly described and ascertained the nature of the said inven-
tion, and in what manner the same is to be performed, as communicated to me
by my foreign correspondent, I declare that what I claim is :-
1. The improved process for grinding and polishing glass more particularly plate
glass, consisting in the rough plates placed on a travelling carriage being operated
on by a number of rapidly rotating cylindrical grinding and polishing rollers
arranged one behind the other, pendulously suspended and pressed on by springs,
and which rollers have also simultaneously a to and fro motion in the direction of
their axes, substantially as herein before described.
2. A machine for carrying out the process specified in Claim 1 in which various
pendulously suspended grinding or polishing rollers W or their oscillating frame A,
or the axes a of the latter, rest in supports Z which are collectively vertically
adjustable in the supports Z¹ by means of screws z and gearing, each grinding or
polishing roller being also vertically adjustable separately, and at each end by
means of the roller carrier A' adjustably arranged in the oscillating frame A by
means of the hand wheel a', substantially as bereinbefore set forth.
3. In a machine such as described in Claim 2 and for the purpose of regulating
the pressure of each grinding roller W, the arrangement at each side of the frame B
and adjustable in supports b, Figures 4 and 5, whereby a greater or less oscillation
may be given to the oscillating frame A by means of the set screws c, and thereby
a corresponding pressure imparted to the grinding rollers as well as the arrange-
ment of a spiral spring / also situated in the adjustable support C over the rod c¹
which may be compressed more or less in the oscillating frame A by means of an
adjustable ring, substantially as herein before set forth.
4. For obtaining a continuous working of the various grinding or polishing
rollers, or for avoiding a return of the carriage, a device for lifting the carriage F
out of or into its slide rails G which have each two cranks g¹ connected with each
other in such a way as to be simultaneously and evenly moved by means of the
lever I that is to say, the carrying rails G are simultaneously lowered or raised and
the carriage F on its runners may be lifted off and carried away as soon as its nut
which conveys the forward motion, is disconnected from the spindle e substantially
as described.
Dated this 21st day of Now 1802
WM. P. THOMPSON & Co.,
Agents for the Applicant.