Improvements in Grinding and Polishing Machines.
Year: 1895

page_text: Date of Application, 14th Feb., 1895-Accepted, 20th Apr., 1895
COMPLETE SPECIFICATION.
Improvements in Grinding and Polishing Machines.
I, EMIL OFFENBACHER, of Markt-Redwitz, in the Kingdom of Bavaria,
Manufacturing 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 grinding, cutting or forming of facets on glass plates or bevelling the same
has been effected heretofore by means of horizontal rotary grinding discs, or by
means of vertical rotary grinding rolls, which latter receive at the same time an
axial motion. The glass plates on which the facets were to be cut were placed
upon the working discs or working tables, and remained under pressure until the
facet was ground away to a sufficient depth.
Now my improvements hereinafter described are more particularly intended for
use with or application to rolls, but are also with some modifications applicable to
horizontal grinding discs.
In the accompanying drawings which illustrate my invention;
Figure 1 Sheet No. 1 is a view in side elevation of my improved machine.
Figure 2 Sheet No. 1 is a view in end elevation thereof (showing part of the
machine only) and
Figure 3 Sheet No. 2 is a view in plan thereof.
Throughout the views similar parts are marked with like letters of reference.
The grinding rolls D which, up to a diameter of about 6 feet and up to a weight
of about 20 tons are formed of one piece of stone, are fixed on a steel shaft H by
means of clamping discs A and B in the following manner :-The disc A is keyed
on fast, whilst the disc B is loosely mounted. Now by means of the nut C and the
screw thread on the shaft, the grinding roll D is clamped between these two discs.
For the purpose of securing or locking this fastening, there is provided on the
disc Ba ring E which engages with the keys or feathers F of the nut C, and is
secured to the clamping disc B by means of a number of screw studs G.
The screw thread on the shaft H should always be a right-hand thread if the
roll rotates in the direction of the arrow, but be a left-hand thread if the roll
rotates in the reverse direction, so that should the roll become loose the continuerl
rotation of the shaft H will cause a tightening of the nut C and thereby produce
an automatic fastening. If it be desired to employ rolls of still greater diameter
or of still greater length, I build up the same of a number of segments. This
arrangement has also the advantage of reduced weight and of greater facility for
transport, and is illustrated in Figures 1 and 3 on the right hand of the shaft H;
the hereinbefore described mode of fastening is shown on the left hand side of the
shaft.
As shown in Figure 1, the roll is composed of six or any other desired number
of parts Nos. 1, 2, 3 etc., which are accurately jointed together and are mounted on
two rings 7 and 8, the arrangement being such that the screw-studs 9 and 10
fastened in the segments are passed through corresponding holes in the rings 7
and 8 and are then secured by means of nuts. For further security, the ring is
provided with a number of lateral lugs 11 through which extend screw bolts 12
that are fixed or cemented in the segments.
As a third and further means of security I also employ endless welded iron
rings of square form in cross section which enter recesses 13 and 14, and are
therein fixed by casting in cement or sulphur. These materials must however not

page_text: be employed to fill up the interstices between the several segments. This must
be effected by means of shellac and sand which has exactly the same grain as the
stone.
Instead of employing segments as just above described, separate rings of artificial
or natural stone may be employed; such rings being then fastened by the same
means of attachment as herein before described with reference to the roll composed
of one single piece of stone.
A further improvement consists in the mechanism for shifting the roll; its
construction being as follows:-The roil shaft H is rotated by means of belts and
the belt pulley J, and is connected by means of the bevel gear wheels K and L
with a crank shaft M which is supported in a fork-shaped bracket O that is
mounted on a turned down part of the shaft H.
The forked bracket O shares in the axial movement and is kept in its horizontal
position by the guide or support R so as to prevent any unintentional rotation.
By the rotation of the crank shaft M there are operated two tie rods N and N¹
which are connected to the main bearing Q, so that an axial movement of the
grinding roll takes place as soon as it is caused to rotate.
In order to produce a uniform or regular facet in the shortest possible time, the
glass plates to be cut have imparted to them a to-and-fro movement, in addition to
their being subjected simultaneously to the grinding action of the rotary movement
and of the axial advance. For this purpose the glass holder a is provided, and
arranged to rock about the shaft b, and is balanced by the counterweight c.
The
journals of the shaft bare mounted on two screw spindles d and e which work in
two pillars fand 9 that are connected together by the cross piece and are capable
of rocking about the eye-bearings i and k. The pillar fis connected by means of
the bell-crank lever k* aud the rods k' and I with a crank m which is fixed on the
aforesaid crankshaft M.
Now as soon as the roll, and with it also the crankshaft M is set in motion, the
said crankshaft M produces, in addition to the axial shifting movement, also a
swinging or rocking motion of the glass holder a which carries the glass. The
amount of this rocking motion can be varied as desired by varying the stroke of
the crank m.
The glass holder a is provided with the mechanism hereinafter described for
effecting the fixing or clamping of the glass and also the automatic grinding of a
rectangular piece, the arrangement being such that first the two long sides and
then the two transverse sides of the plates or sheets of glass are operated upon,
without requiring the aid of a workman for the purpose.
To this end the following arrangement is employed; In the glass holder a is a
worm 15, which gears with the worm wheel 16 in such a manner that the latter
also is able to rock about the shaft b. The shaft is caused to rotate by means
of any suitable gear or shafting, and this motion is transmitted by means of the
shifting belt pulley 17 to the belt pulley 18 which engages by means of a box with
the worm 15.
In this manner the worm wheel 16 is rotated very slowly around the box 19 of
the glass holder a. The frame 21 with its pin 20 and the drum 22 is inserted into
this box.
The drum 22 is connected by means of a chain or rope with the balance weight 23
for the purpose of causing the glass frame 21 to revolve quickly.
This rotation is, however, prevented by the pawl or locking lever 24, which
engages in three corresponding recesses 26, 27 and 28, in the frame 21.
The worm wheel 16 has four tappets 25 which disengage this locking lever and
by the operation of the weight 23 after a determined period of time allow the glass
holder 21 to rotate through an arc of 180° and 90° respectively. This rotary
motion is also executed by the glass 29 which is firmly held on the frame 21 by
means of the arm 30, the clamping disc 31 and the spindle 32.
In order during this operation to obviate any damage to the glass, four ribs 33
are arranged ou the underside of the worm wheel 16 in positions corresponding to

page_text: he tappets 25; these ribs are caused by the rotation of the wheel to to wear up
he standard 34 and thus to raise the glass holder a together with the whole
rrangement clear away from the roll.
When this is done, then the tappet 25 causes the glass to rotate through an are
of 90°, whereupon the entire mechanism will again move down automatically.
The above described arrangement is capable of being employed with all plates
which are of exact square form.
For plates of rectangular form the machine is arranged as follows:-Assuming
that the glass is fixed at its centre upon the frame 21, it will be seen that two of
its sides must always be brought into the same position with relation to the roll.
I shall indicate these long sides by I and II, and the transverse sides by III
and IV, and I proceed as follows:-The glass is fixed in such a manner that the
long side I lies upon the roll, and the weight 23 is in its highest position. The
lever 24 is placed by hand into the recess 28, as shown in Figure 3.
The worm wheel 16 has rotated through an arc of 90°, and this long side is
completely facetted or bevelled. By the tappet 25 the lever 24 is raised, and the
frame 21 rotates through an arc of 180°, because at 35 there is no recess in the
frame, so that therefore the recess 26 comes into engagement with the lever 24.
On further rotation of the worm wheel the second disengagement takes place and a
rotation through 90°, the lever 24 engaging with the recess 27. On further
rotation of the worm wheel the third disengagement takes place and a rotation
through 180°, because at 28 there is a catch which does not allow the lever 24 to
enter the recess 28, so long as the rotation is taking place in the direction of the
arrow. Only when the frame 21 is rotated by hand in the opposite direction, does
the lever engage in this recess, as was stated above in connection with the
commencement of the process. Thus the frame 21 rotates through 180° until the
tappet 37 strikes against the lever 38 and thereby enables the last side to be treated
and finished. This lever is at first out of operation, because it bears on an
interrupted ring 39 on the worm wheel 16 and can only operate when the latter has
rotated, and allowed the lever 38 to fall into the recess 39*.
In this manner the glass, the side I of which was originally set or adjusted by
hand, is rotated through 180° to enable the side 11 to be operated upon, and then
rotated through 90° for operating upon the side III, and then again through 180°
to enable the side IV to be operated upon. But after the side II has been finished,
the glass must be shifted to an amount corresponding to the difference in the
--The heads of the
lengths of the sides; this is effected in the following manner :--
spindles & and e are constructed as guides or slide-ways 40 in which the shaft b was
inserted with the sliding bearings 41. The counterweight 42 which is fixed to the
glass holder a, has a tendency to move the entire apparatus backwards but it is
prevented from so doing by means of the levers 43 which are provided with hooks.
Only at the proper moment, that is to say after the finishing of the side II, does
the tappet 44 fixed in the worm wheel 16 exert a pressure upon the scissors-like
lever arrangement 45, thus causing the simultaneous retraction of the two levers 43,
so that the entire apparatus with the glass holder under the action of the weight 42
is drawn back for a corresponding distance. The limitation of this retraction is
effected correspondingly to the dimensions of the plate, by adjustment of the
slider 46 in the spindle heads 40.
Having now particularly described and ascertained the nature of my said inven-
tion and in what manner the same is to be performed I declare that what I
claim is :-
(1.) A machine for grinding and polishing, in which the grinding roll or grinding
disc is shifted in the direction of its axis during its rotation, with a rocking motion
of the glass holder taking place simultaneously therewith, with the object of
producing a regular or uniform facet or bevel in a short time, as set forth.
(2.) In the machine as specified in Claim 1, or in grinding rolls of any other
kind, the arrangement of a safety ring E or other mode of connection between the

page_text: nut and the clamping disc, together with a correspondingly arranged screwthread
on the shaft H, in such a manner that by the rotation of the shaft the clamping
discs are tightened should the roll D become loose, as set forth.
(3.) In grinding and polishing machines of the kind herein before specified or of
any other kind, the construction of large grinding rolls either of separate stone
segments or artificial stones, which are suitably shaped and fixed upon iron discs
by means of cemented-in screw bolts, and are secured by means of inserted rings
or of separate stoue rings adapted to be held together by means of the clamping
device specified in Claim 2, as set forth.
(4.) In the construction of grinding rolls from separate segments or pieces,
cementing the joints thereby produced, with shellac mixed with sand produced
from the stones themselves, as and for the purpose set forth.
(5.) In grinding rolls of the kind herein before specified or of any other kind,
the arrangement of a shifting device which is actuated direct from the roll-shaft
and moves axially with the latter with the arrangement of a horizontally or
vertically arranged bearing fork O, of bevel wheels K and L, and a crankshaft M,
which are in engagement with the bearing Q or other fixed point by means of a
tie rod or other means, the said fork O being prevented from executing any rotary
movement by means of the support on which it is capable of moving, as set
forth.
(6.) In the grinding or bevelling machines of the kind hereinbefore specified or
of any other kind, the arrangement of a rocking frame which receives by means
of the shifting movement of the grinding rolls or by any other known means, a
rocking motion, in such a manner that the glass can be moved to and fro as desired
along the grinding roll or along the grinding disc, as set forth.
(7.) In the grinding or bevelling machines of the kind hereinbefore specified or
of any other kind, the arrangement of spindles d and e which can be set or adjusted
to any desired height and whose heads are constructed in such a manner as to
allow of shifting the bearings 41, that is to say, of correcting the facet or bevel
during working, as set forth.
(8.) In the grinding or bevelling machines of the kind hereinbefore specified or
of any other kind, the arrangement of a movable glass holder a which serves at
the same time as a guide for a disengaging mechanism by means of which, and
under the action of counterweights or of springs, there is produced at certain
intervals a rotation of the plates to be facetted or bevelled through 90° at a time,
or through 180°, 90° and 180° respectively, whilst at the same time the entire
apparatus together with the glass is raised from off the roll, substantially as
herein before described and illustrated by the accompanying drawings.
(9.) In the grinding or bevelling machines of the kind herein before specified or
of any other kind, the shifting of the entire apparatus in the direction of the
length of the plate under the action of counterweights or of springs which are set
in operation by the disengagement of a scissors-like lever arrangement, as and for
the purpose set forth.
Dated this 14th day of February 1905
ROBERT E. PHILLIPS, M.I. Mech. E.,
Consulting Engineer and Patent Agent,
70, Chancery Lane, London, W.C., Associate Agent.