Improvements in Machinery or Apparatus for Grinding and Polishing Lenses.
Year: 1894

page_text: Date of Application, 7th Apr., 1894-Accepted, 12th May,
1894
COMPLETE SPECIFICATION.
Improvements in Machinery or Apparatus for Grinding and
Polishing Lenses.
1, THOMAS BOURNE, of 76 Stour Street, Birmingham, in the County of
Warwick, Lens Maker, 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 :-
Owing to the considerable cost of grinding and polishing in the manner hitherto
adopted, oval lenses ground convex on one or both sides, such lenses although
often the most suitable, have comparatively rarely been employed for diffusing the
light of lamps and lanterns.
Now this invention relates to machinery or apparatus for effecting the grinding
and polishing of oval lenses from a piece of rough sheet-glass in a simple and
economical manner.
And in order that the nature of my invention and the manner of performing the
same may be clearly understood I will now proceed to describe the same with the
aid of the accompanying illustrative drawing, in which,
Fig. 1 shows in side elevation apparatus constructed according to this invention
applied to a vertical internal grinding or polishing ring, which is shown partly in
section; and
Fig. 2 shows a plan of my apparatus alone.
Referring to Figs. 1 and 2,
1 is an ordinary lathe head-stock provided with fast and loose pulleys 2 and 3,
through the former of which rotary motion is imparted to the vertical internal
grinding-ring 4.
My improved apparatus for carrying and oscillating the piece of glass to be
converted into an oval lens is carried by a pedestal 5 and comprises a frame 6 that
is journalled on a shaft 7 mounted in bearings 5ª in the pedestal 5 and is provided
with an arm 6 that is normally horizontal. On the overhanging end of the shaft
is fixed a pulley 8 adapted to be rotated by a belt 9; on the said shaft is also
fixed a toothed pinion 10 that gears into a toothed wheel 11 fastened on a shaft 12,
which is mounted in the upper end of the frame 6 and has also secured to it a
disc 13 carrying a crank-pin 14. The piece of glass 15 to be ground or polished
is secured, it may be by a layer of pitch, to the lower end of a T-headed rod 16
The
which is fixed in the lower end of a hollow post 17 by a set-screw 18.
post 17 is furnished with lateral extensions 19 which are mounted between two
centres 20 screwed into the forked end of the arm 6. The upper end of the post 17
A lever 22 projecting
is connected by a link 21 with the aforesaid crank-pin 14.
from the frame 6 enables the latter to be turned on the shaft 7 in the direction
of the arrows for the purpose of withdrawing the post 17 and the piece of glass
held thereby, from the grinding-ring 4 when necessary.
When the apparatus is in operation the belt 9 rotates the pulley 8, and thus, by
means of the gearing 10 and 11, causes the rotation of the crank-disc 13, the effect
of which is to produce a slow oscillation of the post 17 and the piece of glass 15
across the annular concave grinding or polishing surface 23 of the ring 4; the
limits of this oscillation are indicated in dotted lines in Fig. 1. By this means
the piece of glass is converted into an oval lens convex at one side. By reversing
the lens its other side may be made convex in a similar manner if desired.
Fig. 3 represents my apparatus diagrammatically and in plan as applied to a
horizontally rotating grinding table or mill 4*, having an annular grinding
surface 23*.

page_text: Although I have shown my apparatus as applied to only two forms of grinding
or polishing mill, it will, of course be understood that it is equally applicable to
other forms.
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. In a machine for grinding and polishing oval lenses, the combination with a
table or mill having a rotary grinding or polishing surface, of a rod or post such
as 17 to which the piece of glass to be operated upon can be fixed in a non-
rotatable manner, an arm such as 6" to which the rod or post is pivotted so as to
oscillate in a plane at right angles to the grinding or polishing surface, and means
for imparting an oscillating motion to said rod or post about its pivots substantially
as herein described for the purpose specified.
2. In a machine for grinding and polishing lenses, apparatus constructed arranged
and operating substantially as described and shown for holding the glass to be
operated upon and for imparting a rocking or oscillating motion thereto in a
direction across the grinding surface.
Dated this ɔth day or April 1894.
For the Applicant,
C
W. LLOYD WISE,
46, Lincoln's Inn Fields, London, W.C., Chartered Patent Agent.