Year: 1899

page_text: Date of Application, 10th Jan., 1899
Complete Specification Left, 10th Oct., 1899-Accepted, 11th Nov., 1899
I, THOMAS BARRY JEBB, of Orillia, Ontario, Canada, Inventor, do hereby
declare the nature of this invention to be as follows:-
This invention has for its object certain new and useful improvements in
optometers used for measuring the limits of distinct vision.
My improved optometer comprises two cylinders of different diameters, the
larger having an end-piece centrally perforated to enable the smaller cylinder
to be secured thereto in alignment with the larger one. The minor cylinder
is provided, near to an eye-hole in its end, with a convex lens, and at the opposite
end, with a concave lens. Suitable stops are arranged between the lenses.
The major cylinder is provided with a ring, on its outer circumference, and
fitted with a pointer which indicates on a longitudinal scale on the cylinder,
the focus at which vision is most perfect.
The major cylinder is mounted upon a stand in such manner that it can be
operated to reciprocate thereon by means of a rack and pinion, and also, by
means of a bifurcated clip and set-screw, in such a way that it can be rocked
and adjusted vertically. An arm projects from the stand to support a mirror
near the end opening in the larger cylinder.
The abutting lenses are fitted in the casing or holder in such manner that they
can be rotated.
P. R. J. WILLIS,
Agent for Applicant.
I, THOMAS BARRY JEBB, of Orillia, Ontario, Canada, Inventor, do hereby
declare the nature of this invention and in what manner the same is to be per-
formed, to be particularly described and ascertained in and by the following
statement:-
1
This invention relates to improvements in optometers, and the object of the
invention is to devise a simple and compact machine of this class whereby
binocular vision may be tested accurately at short range without any muscular
strain on the eyes; and it consists essentially of a cylindrical case "having an
open end supported on a suitable stand and provided with a reduced cylindrical
extension having secured at the end next the major cylindrical portion a con-
cave lens and at the opposite end a convex lens and a slot for the test lenses,
such end being also provided with a holding disc and abbutting lenses supported
i

page_text: in a suitable case opposite the eye hole, the parts being otherwise arranged and
constructed in detail, as hereinafter more particularly explained.
Figure 1 is a sectional perspective, view of my improved optometer. Fig. 2
is an enlarged detail of the lens holder. Fig. 3.is a cross section through Fig. 1.
In the drawings like letters of reference indicate corresponding parts in each
figure.
A is the major cylindrical portion, which is secured on top of a suitable bracket B
having depending lugs bb between which extend the reduced upper end of the
standard C, having a suitable base C'.
0
D is a suitable set-screw which extends through the lugs b b and the reduced
upper end c, serving to clamp the lugs to the upper end c and hold the cylinder
at any desired angle. When the set-screw is loosened the inclination of the
cylinder may of course be changed.
E is a rod extending into the perforated lug e attached to or forming part of the
standard C.
Fis a mirror secured at the end of the rod E on an arm fi stiffly but pivotally
held between the jaws el at the upper end of the rod E, so that the angle of the
mirror may be adjusted to deflect the light as may be desired.
G is a ground glass secured in the open end of the cylinder A. This ground
glass may be provided or not as desired.
H is the focus gauge ring, the central opening of which is concentric to the
axis of the cylinder. The focus gauge ring H has a double flange H having
secured at the bottom the lugs h which extend through a longitudinal slot «
extending substantially from end to end of the cylinder, and a central ground
glass.
I is a spindle extending through the lugs
and provided between them with
a pinion and at one end with a turning knob i
Jis a rack secured to the ends of the bottom of the cylinder and with which
the pinion is designed to mesh in order to adjust the focus gauge ring
longitudinally.
It will be noted that I provide a pointer ³ (Fig. 3) which extends from the
lugs h¹ to the top of the cylinder on which is provided a suitable scale H³, starting
at "
zero in the centre, one end of the cylinder being marked convex, and the
other end concave, as indicated.
"
This scale indicates, when the pointer is. moved along it, the number of the
lens required for long sighted people, and when the pointer is moved in the
opposite direction, the number of the lens required for near sighted people, as
will more particularly appear hereinafter.
A¹ is the inwardly extending flange at the near end of the cylinder, to which
is affixed the minor extension cylinder, the axis of which is on a line with the
axis of the major cylinder.
K is a concave lens secured to the inner end of the minor cylinder in proximity
to the major cylinder, and K³ is a convex lens secured near the opposite end of
the minor cylinder.
K2 is a slot for the insertion of trial lenses should it be desired to use the same.
L is an end disc provided with a retaining plate L', secured to the inner
plate L, which has a circular hole in which fits the disc M. The disc M is
provided with concentric outward extensions M¹ and M³, the extension,M³ being
threaded at its outer end so as to receive the end cup-shaped eyepiece N, which
is provided' with a central eye hole n. The disc M is also provided with a central
eye hole m.
O are a pair of convex lenses, which abut each other opposite the centre of the
eye holes mn, the edges of the lenses being preferably ground off, so as to form
a substantially straight line through the centre of the eye hole. The lenses O
are fitted in with a suitable composition which holds them securely in position.
The disc Mis rotated by means of the handle m so as to partially rotate the
lenses O. As the edges of the lenses are in the centre of the eye-hole it will be

page_text: seen that in looking through my optometer there will appear two openings at
the end of the cylinder. As a convex lens is used in the minor cylinder next
the eye hole and a concave lens farther away from the eye hole it will also be
seen that the imaginary double opening in the large cylinder will appear at a
much greater distance or farther away than it is in reality, thus effectually pre-
venting any muscular strain on the eyes and enabling me to obtain in a compact
machine all the advantages derived from the use of test cards heretofore utilized
at a distance.
By the use of the mirror F, herein before described, the instrument may be set
so that the person has his back to the light, as the light will be reflected into
the open end.
The focus gauge ring may also be adjusted, as described from the zero point
towards the eye-piece in the case of long sight, and away from the eye-piece
in the case of near sight, so as to ascertain the number of glass required. By
this means binocular vision may be accurately determined. Of course the use
of the focus gauge ring does not in any way do away with trial lenses, which
may be inserted in the slot K³, if thought necessary in some cases where it is
extremely difficult to obtain accurate lenses.
Although I shew in this invention, abutting convex lenses opposite the eye-piece
it will of course be understood that I might use abutting concave lenses and
produce practically the same effect. I, however, prefer the use of convex lenses.
Having now particularly described and ascertained the nature of my said
invention, and in what manner the same is to be performed, I declare that what
I claim is:-
(1) In an optometer, in combination suitably abutting lenses, the holder for
same provided with suitable eye holes in which the abutting edges of the lenses
are in the central line of sight, the minor cylindrical portion provided next the
eye hole with a convex lens and at the opposite end with a concave lens, the major
cylinder forming an extension thereof and provided with an end opening as and
for the purposes specified.
(2) In an optometer, in combination suitable abutting lenses, the holder for
same provided with suitable eye holes, in which the abutting edges of the lenses
are in the central line of sight, the minor cylindrical portion provided next the
eye hole with a convex lens and at the opposite end with a concave lens, the major
cylinder forming an extension thereof and provided with an end opening and
a suitable stand for the major cylinder as and for the purpose specified.
(3) In an optometer, in combination suitable abutting lenses, the holder for
same provided with suitable eye holes in which the abutting edges of the lenses
are in the central line of sight the minor cylindrical portion provided next the
eye hole with a convex lens and at the oposite end with a concave lens, the major
cylinder forming an extension thereof and provided with an end opening, a
bracket secured in the centre of the major cylindrical portion and provided with
depending lugs, a stand provided with a reduced upper end and a clamping screw
extending through the lugs and reduced end as and for the purpose specified.
(4) In an optometer, in combination suitably abutting lenses, the holder for
same provided with suitable eye holes in which the abutting edges of the lenses
are in the central line of sight, the minor cylindrical portion provided next
the eye hole with a convex lens and at the opposite end with a concave lens, the
major cylindrical portion forming an extension thereof and provided with an
end opening, a suitable stand for the major cylinder and a mirror and arm
supporting the same as and for the purpose specified.
(5) In an optometer, the combination with the eye-piece and lenses, adjacent
to said eye-piece having abutting edges, of the minor cylinder, the convex lens
located in same next the eye-piece, the concave lens located at the opposite end,
the major cylinder and the focus gauge ring and pointer and scale on the cylinder
all arranged as and for the purpose specified..

page_text: (6) In an optometer, in combination suitable abutting lenses, the holder for
same provided with a suitable eye hole in which the abutting edges of the lenses
are in the central line of sight and means for rotating the lenses as and for the
purpose specified.
!
1000