Improvements in Prismatic Binocular Field and Opera Glasses.
Year: 1897

page_text: PROVISIONAL SPECIFICATION.
Improvements in Prismatic Binocular Field and Opera Glasses.
JOHN HENRY BARTON, 19, Honeywell Road, Wandsworth Common, London,
S.W., England, Optician's Assistant, do hereby declare the nature of this inven-
tion to be as follows:-
The object of this invention is to obtain the greatest possible facility in the
adjustments necessary to the convenient use of this class of instrument."
In order to attain this end, the two prismatic telescopes forming the right and
left main bodies of the instrument are mounted between two bars in such manner
that the occulars of the instrument can readily be adjusted for difference in the
widths between the eyes of various users; this action to some extent resembles
but
that of an ordinary field glass having what is known as jointed centres
with the important difference that there are two centres of motion instead of one,
and these centres of motion are the optical centres of the objectives.
<
Rising out of about the middle of the topmost of these bars aforesaid is a movable
pillar or other support which carries a third bar and at each of the extremities
of this third bar is a jointed arm the centres of motion of these two jointed arms
is always the optical centres of the objectives; the other ends of these said arms
are attached to the occulars of the instrument and by means of a milled head
actuating the movable pillar aforesaid the instrument is focussed.
-
The right & left bodies of the instrument moving in, or on the optical centres
of the objectives in the manner aforesaid, are geared together in such manner that
each moves in equal degree.
100W
Improvements in Prismatic Binocular Field and Opera Glasses.
I, JOHN HENRY BARTON, of 19, Honeywell Road, Wandsworth Common, in the
County of London, Optician's Assistant, do hereby declare the nature of this inven-
tion and in what manner the same is to be performed to be particularly described
and ascertained in and by the following statement:-
-
This invention relates to prismatic binocular field and opera glasses; that is
glasses in which increased magnifying power is obtained within a short length
by directing the rays alternately in either direction by reflecting prisms between
the objectives and the eye pieces and the distance of the eye pieces from each

page_text: other being adjustable to suit different users and the object of the invention is
to obtain in a compact form the greatest possible facility in the adjustments
necessary to the convenient use of this class of instrument-the arrangement
being such that the distance apart of the eye pieces is varied without varying
the distance apart of the objectives. I will describe a manner in which my inven-
tion may be carried into effect reference being had to the accompanying drawings.
Figures 1 and 2 are end views at the eye piece end shewing respectively the eye
pieces adjusted at their least distance apart and Figure 2 shewing them adjusted
at their greatest distance apart. Figure 3 is a plan partly in section on the
line 1-2 Figure 1 and Figure 4 is an end view at the objective end of the instru-
ment. The two prismatic telescopes forming the, right and left main bodies ab
of the instrument are mounted between two bars cd in such manner that the eye
pieces of the instrument can readily be adjusted for difference in the width between
the eyes of various users without altering the relative positions of the objectives
by turning the bodies a and b about the two centres ab which are the optical
centres of the objectives. As shewn in the drawings the bodies a and b are each
mounted between the bars cd each being supported at one end by the pin or short
trunnion entering bearings in the bar d and at the other end by the tubes of the
objectives which are attached to the bodies a and b and work in orifices in the
bar c.
Between the mid portions of the aforesaid bars cd is a piece e preferably of
triangular shape in cross section in which is a screw nut in which works a screw
on the pillar f which carries a third bar 9 and at each of the extremities of this
third bar is a jointed arm hi the centres of motion of these two jointed arms
being the optical centres of thé objectives; the other ends of these said arms being
attached to the eye pieces of the instrument. By means of the milled head f
carried by the pillar f the instrument is focussed as the bar g and arms hi move
the tubes carrying the eye pieces to and fro along the tubes k. The bar
shewn as being provided with outside strengthening pieces g³.
is
As the right and left bodies ab of the instrument are turned about the optical
centres of the objectives in the manner aforesaid the eye pieces are adjusted to
different distances apart without altering the distance apart of the objectives.
In order that each eye piece may move simultaneously and to the same degree
the bodies a and b have attached to them means by which the motion of the one
is conveyed to the other. This is shewn in the drawing as being effected by
curved bars Im with engaging teeth in segments of circles struck respectively from
the optical centres upon which the bodies a and b turn. The stop n on the bar c
limits the motion in either direction by coming against stops formed by the ends
of the slot m² in the bar m.
I have omitted the prisms and lenses from the drawing as their representation
is not necessary for the understanding of my invention.
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 prismatic binocular field or opera glasses the combination with the objec-
tives of bodies carrying the prisms and eye pieces mounted so as to be capable of
partial rotary movement about the optical centres of the objectives substantially
as liereinbefore described.
2. In prismatic binocular field or opera glasses the combination with the objec-
tives of bodies carrying the prisms and eye pieces and mounted between bars
such as cd connected by a piece such as e the said bodies being capable of partial
rotary movement about the optical centres of the objectives substantially as herein-
before described.
3. In prismatic binocular field or opera glasses the combination with the objec-
tives of bodies carrying the prisms and eye pieces mounted so as to be capable of

page_text: partial rotary movement about the optical centres of the objectives and geared
together so that they move equally and simultaneously substantially as herein-
before described.
4. In prismatic binocular field or opera glasses the combination with the objec-
tives of bodies ab capable of partial rotary movement and geared together and
carrying the prisms and eye pieces and supported by bars c and d with the piece e
between in which works a pillar f carrying a bar g to which the tubes for the eye
pieces are connected by arms hi all substantially as, and for the purpose, herein-
before described.
Tated this 20th love of Tune 1908
JOHNSONS & WILLCOX,
47, Lincoln's Inn Fields, London, W.C., Agents.