An Improvement in Ophthalmoscopes.
Year: 1892

page_text: Date of Application, 21st Mar., 1892-Accepted, 4th June, 1992
COMPLETE SPECIFICATION.
An Improvement in Ophthalmoscopes.
We ARTHUR WILLIAM DOWN and HUBERT VINCENT DOWN both of Nos. 5
& 7 St. Thomas's Street Borough in the County of London trading together in
partnership as Surgical Instrument Manufacturers under the style or firm of
"Down Bros.," and RICHARD HENRY FERRIER of 56 Beresford Street
Walworth in the County of London aforesaid Optical Instrument 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 :-
The invention is an improvement upon what is known as Mortons ophthalmo-
scope and consists in the novel form of link lens holder. It is constructed to hold
the lens and for the additional and novel purpose of indicating the power of a lens
thus dispensing with time wheels or other means of shewing the power of a lens
when presented at the sight aperture thereby reducing the number of working
parts in an ophthalmoscope and rendering the instrument less liable to get out of
order, and is accomplished as set forth in the following description and drawing
accompanying this Specification :-
In the drawing,
Figure 1 is a plan of the tray links and driving wheel of an ophthalmoscope
the tray back or upper surface plate is removed to show the links in position.
The links are represented by thirty circles and are not attached to each other but
work freely between the two surface plates. They are guided in their course by
the link race E, E. The large circle D. is a milled wheel fixed to a small steel
wheel C, whereby the chain of links is set in motion. F. indicates the position in
the upper surface plate of the reading aperture and G. of the sight aperture.
Figure 2. is a section of Figure 1. at the line A. B.-E. E. is the link race or
tray with the links removed.
Figure 3. is the complete link lens holder. K. is the lens. J. the cell holding
the same and H. the wing which carries the number or sign of lens power of a
lens a given number in advance.
Figure 4. is a section of Figure 3. with lens.
A wing of metal or other suitable material is attached to each lens holder. It
is so fashioned in shape as to permit of the series of lenses and wings easily
travelling in the link race or tray both in a straight line or revolving in a circle
and is of sufficient size for a figure, or figures, or sign or signs indicating the
power of a lens to be placed upon it (see Figure 3).
The number or sign placed on the wing is that indicating the power of the lens
a given number in advance so that when lens of power No. 1 occupies the position
at the sight aperture (see G Figure 1) its number which is attached to a lens a
few intervals from it appears at the reading aperture (see F. Figure 1).
The reading aperture is placed away from the sight aperture for convenience
and so as not to obstruct the vision.
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 novel application to ophthalmoscopes of a wing attached to a revolving link
lens holder to indicate the number, sign, or power of the lens in position.
Dated this 21st day of March 1892.