Machine for Rough Grinding Glass Discs for the Production or Lenses.
Year: 1895

page_text: France),
Date of Application (in United Kingdom), 30th Mar., 1895
Complete Specification Left, 28th Dec., 1895-Accepted, 28th Mar.,
1896
PROVISIONAL SPECIFICATION.
Machine for Rough Grinding Glass Discs for the Production or
Lenses.
We, THE SOCIÉTÉ PARISIENNE DE VERRERIE OPTIQUE of 20 Rue Félicien David,
Paris, in the Republic of France, do hereby declare the nature of this invention to be
as follows:-
This invention has for its object the preliminary grinding of the faces of a disc of
glass, to produce a lens for optical purposes, and the invention consists in a special
arrangement of machine for effecting this object.
In carrying out this invention, the glass disc is attached by means of pitch to the
exterior of a semisphere carried at the end of a pendent vertical shaft or spindle, to
which rotary motion is communicated in any convenient manner, a forked lever
taking into a grooved pulley on the shaft being employed to raise the shaft when
required.
This semisphere is arranged to enter a hollow semisphere carried by a vertical shaft
or spindle, which is mounted in a peculiar manner, and when the parts are spherical,
they are preferably arranged slightly excentric.
The shaft of this hollow piece is fixed in a square socket, on each face of which (at
its lower part) is a hole to receive a pin having externally of the socket, three inclined
planes, the four pins pressing against a ball contained in the socket, and placed
between two other balls, the lower of which forms a pivot for the socket, while upor
the upper ball rests the end of the shaft.
The lower ball rests on the bottom of a square box, to each side of which are
secured the supports for three friction rollers, which are respectively placed opposite
the three inclined planes of each pin. The socket will thus be able to oscillate on its
pivet within certain limits, and its parts coming into contact with the rollers, friction
will be considerably diminished.
The box is provided with a stump, which is recessed to fit over a pivot pin, a ball
being placed between the end of the recess and the end of the pin.
The parts contained in the box are protected from dirt by a cover, which is secured
to the socket, and is connected to arms projecting from the bottom of the box by
springs.
The pivot pin last mentioned is connected to a slide working in guides secured to a
plate or disc, and the plate is mounted on the end of a vertical shaft or spindle,
suitably mounted, and to which rotary motion is communicated in any convenient
manner.
Fitted to the stump, and projecting radially therefrom, is a slotted arm, which
works on a pin carried by a standard bolted to the table of the machine, the
outer end of this arm being supported by stay rods connected with the cover.

page_text: On rotary motion being communicated to the shaft, the disc is rotated, and the
pivot pin with the socket is caused to describe a circle of a diameter varying
according to the distance of the axis of the pivot pin from the axis of the disc
on which it is fixed. As the socket cannot rotate by reason of the slotted arm,
an oscillatory motion will be given to the hollow semisphere on the top semisphere,
which is being rotated at considerable speed, so that the surface of the glass disc
carried thereby will be ground, some wet sand being interposed between the surface
of the semisphere and the glass.
As a modification, the disc may be recessed on its underside, and provided with
internal teeth. The vertical shaft carries a spur wheel, which, through a pinion
mounted on a stud carried by the disc, drives the disc.
In this case the socket arrangement may be dispensed with, and the shaft
of the lower semisphere may be connected to the slide direct by a universal
joint.
Dated this 20th day of March 1905
NEWTON & SON,
Agents for the Applicants.
Machine for Rough Grinding Glass Discs for the Production of
Lenses.
We, THE SOCIÉTÉ PARISIENNE DE VERRERIE OPTIQUE of 20 Rue Felicien David,
Paris, in the Republic of France, 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 :-
This invention has for its object the preliminary grinding of the faces of a disc of
glass, to produce a lens for optical purposes, and the invention consists in a special
arrangement of machine for effecting this object.
In the accompanying drawings,
Fig. 1 is an elevation of the machine which forms the subject of this invention.
Fig. 2 being a section on the line 1-2.
Fig. 3 is a vertical section of the box M and cap O of the machine on an enlarged
scale.
Fig. 4 is an underneath view of the box.
Fig. 5 shows a slight modification in the form of the machine.
The glasses are cemented by means of pitch, or other adhesive material, to the
exterior surface of a spherical cap B, fixed to the lower end of a shaft C, which
carries on its upper end the fast and loose pulleys D and D¹ for driving. A grooved
collar E, into which take the arms of a fork F, terminating in a handle G, permits of
the shaft C being raised to change the cap B, when necessary.
The cap B enters a hollow cap H, having a rim h. The shape of these caps B
and H depends on the form it is desired to give to the glasses operated upon,
but in every case, if these caps are spherical, they will not be concentric with respect
to each other, but slightly excentric, because, if it were otherwise, only a small part
of the glasses cemented to the cap B (those in the centre) would be properly dressed,
whilst the others, those at the edge, would not be uniformly ground. The centre
of the cap H should be a little higher than that of the cap B in the same vertical
line.
The cap H is mounted upon a shaft I, fixed at its lower extremity in a piece J,
which is arranged in the following manner.
This piece, which is hollow in the middle, is pierced on each of its 4 faces by an
opening, into which penetrates the projecting part of the piece K, having inclined
planes on its three sides, k, k' k". Inside the piece J, the pieces K abut against a

page_text: ball L, which rests upon 2 balls L' and L", of which one, L", serves as a bearing for
the piece J, and consequently for the shaft I, on the bottom of the box M. This
box M is square, and upon each of its sides are fixed the supports of three,
bowls N, N', N", which are situate respectively in front of the three inclined
planes k, k of the corresponding piece K. By means of this construction, it.
will be seen that the shaft I, and consequently the piece J, can oscillate around its
bearing point I, and in these movements the different parts of the piece J will come.
in contact with the bowls N, N', N", which considerably diminishes the friction.
To prevent the dust from getting into the mechanism we have just described, it
is protected by a cover 0 (Fig. 3), which is held by springs P to the arms Q,
fixed underneath the box M. The box M is provided at its under side with a
buss or projection m, which is hollowed out at m'. In this hollow is placed a
ball m, upon which bears the end of the vertical supporting pin R of the box M.
This supporting pin R is fitted at its lower end with a slide 'R', which runs in a
guide R fixed to the plate S (Figs. 1 and 3). By means of a clamping nut 3, the
position of the slide R' in the guide R" can be regulated at pleasure, and consequently
the distance from the centre of the plate S shortened. This plate S is mounted on
the upper
end of a vertical shaft S¹, on which are fixed the fast and loose pulleys T.
The shaft S rests, at its lower end, in a socket U, furnished with a ball. A
screw U and nuts U₁ permit of the regulation of the position of the bracket at
pleasure.
The machine receives, therefore, two movements. One movement is imparted
to the shaft C, and consequently to the cap B, by the driving pullies D and D¹;
this movement has no action upon the internal mechanism of the machine.
The second movement, which is rotary, is transmitted to the plate S of the
machine by the driving pulleys T. This movement has no action upon the cap B,
and only acts upon the cap H, in the following manner. The pin R, carried
round by the plate S, describes a cylindrical figure, or circle having as a radius the
distance which separates the shaft from the axis of the plate S. The box M is carried
round by this movement, and so that it shall not turn round upon itself at the same
time, it is connected to a slide V, the function of which will be seen presently. We
would remark that it is owing to this connection, by the simple interposition of a
ball between the box M and the shaft R, that the box M is prevented from turning
round, when carried round by the shaft R. The ball L' in the box M, which is
carried round in its movement, describes a circle about the axis of the plate S, and
the axle I, which only rests upon the box M, through the ball L', describes a conical
figure, and the cap H takes an alternating oscillatory movement.
As we have above explained, we prevent the box M from turning upon itself, by
come we gave above we prevent the box from turning upon itself,
The
which surrounds the boss or projection m, and to which it is fixed by a screw v.
slide V follows the movement of rotation of the box M around the axis of the plate S,
bearing against the bowl X, mounted loosely on an axle fixed to the table Y. The
rods W, pivotted upon the slide V, regulate the movements of the cover O, and
prevent its upsetting.
The machine being stopped, the shaft is lifted, and a cap B fixed at its lower
extremity. On the outer face of this cap are cemented the glasses to be ground, and
the shaft C is allowed to descend till the cap B comes within the cap H, and then
some very wet sand, or, more exactly, water charged with sand, is put between the
two surfaces or caps.
The machine is set in motion, and when the operation is finished, it suffices to raise
the shaft C, and to change the cap B. One workman can therefore attend to a large
number of machines, which diminishes hand labour to a considerable extent.
In Fig. 5 we have shewn a modification of our machine. The plate S is hollow,
and the inner wall 3 of the hollow portion is toothed; the shaft S¹ carries on its
upper end a wheel 1, which engages with a pinion 2, mounted loosely on a fixed axle
in the plate S. This pinion 2, in its turn, engages with the inner toothed edge of
the plate S. The plate S is therefore set in rotary motion, as in the previous

page_text: arrangement. The slide R' on the plate S is not modified, but the box M is replaced
by a universal or "Cardau" joint 4, which gives the same movement as before to the
cap H. Nothing is modified in the working of the apparatus.
Having now particularly described and ascertained the nature of our said
invention and in what manner the same is to be performed, we declare that what we
claim is
The machine for roughly grinding optical glasses as above described, in which
the round and flat discs of glass take successively, upon each of their faces,
approximately the form which they shall definitely have, whatever may be this
definitive shape, as set forth.
Dated this 20th day of Doosmbon 10UK
NEWTON & SON,
Agents for the Applicants.