Improvements in Instruments for Measuring Distances.
Year: 1897

page_text: Date of Application, 12th Nov., 1897-Accepted, 29th Jan., 1898
COMPLETE SPECIFICATION.
Improvements in Instruments for Measuring Distances.
"'
I, JOSEPH THOMAS BROWN, Physician, of Houstonia, in the County of Pettis,
and State of Missouri, one of the United States of America, 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 instruments for measuring distances, and while
especially designed for use upon ship board for ascertaining the distance of the
vessel from a given object, is also useful upon shore for a similar purpose.
The object of the present invention is to provide a simple, cheap and reliable
device by means of which the distance, as above indicated, may be accurately
determined in a short space of time and without requiring any calculations.
To the above end the invention consists in a measuring instrument embodying
certain novel features and details of construction and arrangement of parts as
hereinafter fully described, illustrated in the drawing and pointed out in the claims
hereto appended.
In the accompanying drawings
Figure 1 is a plan view of the measuring instrument constructed in accordance
with the present invention.
Figure 2 is a detail cross section through the arcs.
The improved instrument comprises an angle 1, the arms of which extend at
right angles to each other. The device comprises three arms, 2 designating the
longer arm and 3 the shorter arm, arranged parallel to, but spaced apart from the
arm 2, the arms 2 and 3 being rigidly connected by a cross arm 4, arranged at
right angles thereto and forming the base of the triangle used for calculating the
distance of the given object from the point of operation.
5 designates a swinging arm or pointer which constitutes the hypothenuse of a
right-angle triangle, the other two sides of which are formed by the arms 2 and 4,
4 constituting the short arm or base of the triangle, and 2 the longer side or arm
perpendicular to the base. The pointer 5 is pivotally connected to the device
at the intersection of the portions 3 and 4. 7 designates a graduated double arc
which is connected at one end to the outer end of the arm 3 and at its opposite end
to the intersection of the portions 2 and 4 of the device. The double arc has a
central curved slot, a superior arc 7¹ and an inferior arc 7", the superior arc being
graduated and marked off in distances in feet, yards and miles, while the inferior
arc is provided with graduations laid off in degrees.
In operation, the instrument is placed upon a table or other suitable support,
and the long arm 2 is pointed straight towards the object, the distance of which
is to be measured. The swinging arm 5 is adjusted so that it will point directly.
to the same object. When both of said arms are pointed towards the object it is
only necessary to note what graduation on the superior arc the swinging arm tallies
with, which will immediately indicate the distance.
The device is extremely simple, may be manufactured at a slight cost and will
be found of great convenience especially in times of war, where it is desired to
fnd cut accurately the distance at which the enemy is located.

page_text: In order to prevent the swinging arm from lifting or moving out of contact with
the arc 7 the arm 5 is provided with a lip or plate 9 which engages under the
stationary arc 7 and prevents relative movement between the arm and the arc,
while permitting the arm to slide around on the stationary arc.
The arm 5 pro-
jects beyond the arc 7 and has an observation opening 10 with oppositely projecting
pointers 11 to register with the graduations on the arcs.
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. An instrument for measuring distances consisting of a frame comprising
parallel bars connected at their ends by a cross bar, a stationary graduated arc
secured at its opposite ends to said frame, a swinging arm pivotally connected to
said frame, and an extension on said arm bent to extend around and beneath one
edge of the stationary are for maintaining the swinging arm in proper relation
thereto, substantially as described.
2. An instrument for measuring distances, consisting of a suitable horizontal
frame comprising parallel bars connected by a cross bar, a stationary are secured
at its opposite ends to said frame and provided with graduations as described, and
a swinging arm pivotally connected to said frame and provided with a flange which
embraces the stationary are, substantially as and for the purpose described.
Dated this 11th day of November 1897.
H. B. BARLOW & GILLETT,
Agents for Applicant, 17, St. Ann's Square, Manchester.