Improvements in Theodolites, Levels, and the like.
Year: 1896

page_text: Date of Application, 11th Nov., 1896
Complete Specification Left, 16th July, 1897-Accepted, 21st Aug., 1897
PROVISIONAL SPECIFICATON.
Improvements in Theodolites, Levels, and the like.
I, ARTHUR WILLIAM BRIGHTMORE, of Burford House, Knighton, in the County of
Radnor, Civil Engineer, do hereby declare the nature of this invention to be as
follows:-
The invention concerns the adjustment of the line of collimation in the telescopes
of theodolites, levels & the like. In one arrangement, when adjustment in one
direction only is required, a diaphragm, with a hole through the middle, is fixed at
the eye-piece end of the telescope; this diaphragm has a bevelled groove, in the
direction that adjustment is required, of greater width than the hole, either cut in
it, or formed by cheeks with bevelled edges fixed on to it. A plate, fitting into the
groove, with a hole through it, over which the cross-hairs are stretched, slides in
the groove, by means of a screw, supported so as to be capable only of rotation.
When the screw is turned, it causes the plate with the cross-hairs to travel in the
groove.
If adjustment in two directions, at right angles to each other is necessary, a second
plate, instead of the first one named, has the cross-hairs stretched across a hole
through it; it has bevelled edges and slides in a groove, (similar to the one above
described,) in the first plate, but in a direction at right-angles to the first groove, by
means of a screw as before; but, when the first plate is moved by its screw, both the
second plate and its screw travel with it. The screws are pressed against the faces of
the supports, which prevent them from moving longitudinally, by means of springs.
The screws can either have milled-heads, or have their heads protected & be made to
turn with the blade of a pocket-knife, or in any other manner.
Dated this 10th day of November 1896
ARTHUR WILLIAM BRIGHTMORE.
I, ARTHUR WILLIAM BRIGHTMORE, of Burford House, Knighton, in the County
of Radnor, Civil Engineer, 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 relates to the adjustment of the line of collimation in the telescopes
of theodolites, levels & the like. In one arrangement, when adjustment in one
direction only is required, a diaphragm, with a hole through the middle, is fixed at
the eye-piece end of the telescope; this diaphragm has a bevelled groove, in the

page_text: direction that adjustment is required of greater width than the hole, either cut in it
or formed by cheeks with bevelled edges fixed on, to it. A plate, fitting into the
groove, with a hole through it, over which the cross-hairs are stretched, slides in
the groove, by means of a screw, supported so as to be capable only of rotation.
When the screw is turned, it causes the plate with the cross-hairs to travel in the
groove.
If adjustment in two directions at right-angles to each other is necessary, a second
plate, instead of the first one named, has the cross-hairs stretched across a hole
through it; it has bevelled edges and slides in a groove, (similar to the one above
described) in the first plate, but in a direction at right-angles to the first groove, by
means of a screw as before; but, when the first plate is moved by its screw, both the
second plate & its screw travel with it. The screws are pressed against the faces of
the supports, which prevent them from moving longitudinally, by means of springs.
The screws can either have milled heads, or have their heads protected & be made to
turn with the blade of a pocket-knife or in any other manner.
In order that this said invention, and the manner of carrying the same into effect
may be fully understood there is hereunto appended an explanatory sheet of drawings.
Figures 1 & 2 are sections of my invention for adjustment in one direction, &
Figures 3 & 4 the same for adjustment in two directions. Figure 1 is a section
through the sliding plate A, showing the screw B, the cover-plate C & the spring D
pressing the sliding plate against the cover-plate. Figure 2 shows a transverse
section through the diaphragm & sliding-plate. Figure 3 shows the sliding plate A,
with screw B, cover-plate C & spring D, which slides across the plate A¹, which slides
in a direction at right-angles, carrying with it the sliding-plate A, screw B & spring D.
The screw B¹ moves the plate A¹ & the spring D¹ presses the screw B₁ against its
cover-plate. Figure 4 is a vertical section through the diaphragm, showing sections
of plates A & A¹, the screw B¹ & the spring D¹.
Having now particularly described & ascertained the nature of my said Inven-
tion, & in what manner the same is to be performed, I declare that what
I claim is
The use, for adjusting in any direction the cross-hairs, or whatever corresponds
thereto, in surveying instruments, of a single screw & a spring to press the screw
against its support.
Dated this 13th day of July 1897.
ARTHUR WILLIAM BRIGHTMORE.