Improvements in Rotary Measuring Instruments for Measuring or Calculating Distances on Maps, Charts, Plans, or similar Surfaces.
Year: 1889

page_text: COMPLETE SPECIFICATION.
Improvements in Rotary Measuring Instruments for Measuring or
Calculating Distances on Maps, Charts, Plans, or similar
Surfaces.
I, ROBERT JARVIE BUORANAN, Accountant, a Subject of the Queen of Great
Britain, now residing in Pittsburgh, Pennsylvania, U.S.A., 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 object of my invention is to provide a simple and reliable instrument for
measuring or calculating distances on maps, charts, plans, or similar surfaces.
In carrying out my invention, I provide a disc, wheel, or roller having its side or
sides marked near the periphery with a scale made in accordance with some unit of
measure such as inclies and an additional scale or additional scales, within the
outer scale, divided to indicate distances calculated by a larger unit of measure—such
as miles. The disc, wheel, or roller is mounted in suitable bearings, which are
connected with a frame having a handle by means of which the rotary measure may
be moved along the surface to which it is applied.
A pointer or index is pivoted concentric with the rotary measure, and indicates, on
the scales, the distance moved.
Other features of my invention and the details of construction will be hereinafter
more particularly specified.
In the accompanying drawings
Fig. 1 is an elevation of one side of the disc, wheel, or roller, showing the scales
on its face and the pointer or index, which is pivoted concentric with the disc.
Fig. 2 is a longitudinal, central section through the disc, wheel, or roller, showing
the frame and handle in elevation.
Fig. 3 is a detail view of the pointer,
Figure 4 illustrates a modification.
and
The disc, wheel or roller is preferably constructed as follows-
As shown in Fig. 2, a bushing or core A, of suitable material, such as brass, wood,
or vulcanized fibre, is formed with a central shaft-opening and with laterally
projecting bosses a¹. On each side of the bushing is secured a circular plat B,
which is provided with apertures through which extend the bosses a'.
D

page_text: The plates B, extend beyond the outer edge or circumference of the hushing A,
and their edges are preferably formed as shown, straight or plain on the outer sides,
and tapered or beveled downwardly or inwardly on their inner sides.
Between the plates B, and closely surrounding the bushing A, is secured a rim or
tire O, preferably of some soft material-such as soft vulcanized rubber-and this
rim or tire projects a slight distance beyond the peripheries of the discs.
A shaft or
axle D, extends through the central opening in the bushing A, and its bosses a', and
is secured, at its outer ends, to a U-shaped frame E, to which is secured, by means of
a screw e, a handle F. The bosses a', have laterally projecting extensions a², which
nre preferably of smaller diameter than the main portion of the bosses, and on
these extensions are pivoted the indexes or pointers G. One of these pointers is
shown separately in Fig. 3. As will be seen, it consists of a central hub from
which extends downwardly a straight arm g', made sufficiently heavy to hold it in an
upright position. The pointer, which is preferably triangular in cross-section, is
tapered or beveled at its outer end, from its front face downwardly to the apex or
knife-edge, at the rear face, to form a triangular index g, at that end which lies close
to the scale on the outer edge of the plate. A second index or pointer g³, extends
from the hub g, in an opposite direction to that of the pointer g', and is made
narrow and light, so as not to counterbalance the pointer g', and not to cover up the
scale or scales in connection with which it is used.
In the drawings, I have shown the pointer g³, as gradually tapering from its inner
end outwardly, as I prefer this construction.
As before stated, two of these pointers are employed, one on each side of the
rotary marker, being hung freely from the extensions a², of the bosses. The indexes
or pointers thus always maintain a perpendicular position or direction, and the rotary
marker moves relatively to the pointers on each side. The screws a³, which secure
the frame E, to the roller, are removable, so that the discs, frame, and indexes may be
separated and other discs, having differently marked scales, may be substituted.
The discs B, may be divided into scales, as indicated in Fig. 1. As seen in this
figure, a circular scale a, divided and graduated into inches and fractions of an inch,
is formed around the edge or periphery of the dise. Within this circular scale, is
a second scale y, shown as divided, to indicate milos and fractions thereof; as
represented, it is graduated to indicate three miles to the inch, so that, when the
measuring disc, wheel, or roller is moved one inch on a surface to which it is applied,
when scaled to three miles to the inch, the index on the inner scale will indicato a
distance of three miles traversed.
It is obvious that any other unit of measure may be employed for either scale, but
I prefer that shown and described, as my invention is especially designed for
measuring distances on maps and plans. By having a disc and index on each side of
the instrument, and, as each disc may have several scales, it may be made to measure
surfaces laid out on different scales. The discs are removable or interchangeable, so
that others differently marked or scaled may be substituted. Thus the instrument
may be used in connection with maps, charts, etc., having different units of
measurement, or made to different scales."
By employing a yielding tire for the wheel, the instrument is not apt to slip, but
will nove truly over the surface to which it is applied. The edges of the discs
being beveled or inclined, when the instrument is applied to a surface being measured,
the tire will be compressed within the recesses formed by the bevels, so that the
edges of the discs will move along the surface, and in this way a true, and uniformn
measurement may be obtained, while the soft, flexible tire enables the instrument to
take a firm hold, without slipping, upon the measured surface.
In Figure 4, I have shown a slight modification of the instrument, in which two
metallic discs B, are directly connected by attaching devices b. A tire C, circular in
cross-section, is seated in a recess c, between the discs at their periphery, and projects
a slight distance beyond it; a, indicates the shaft-opening and a³, the bosses or
bearings for the indexes or pointers.

page_text: Having now particularly described and ascertained the nature of my said inven-
tion, and in what manner the same is to be performed, I declare that what I
claim is
1. The combination, substantially as hereinbefore set forth, of the frame, its handle,
the rotary disc, wheel, or roller pivoted to the frame, and having scales of distances
marked on its side, and an index or pointer pivoted concentric with the disc, wheel,
or roller and weighted and pointed at its lower end.
2. The combination, substantially as herein before set forth, of the frame, the rotary
disc, wheel or roller, the scale marked on its side, and near its periphery in
accordance with one unit of measure, a socond scale or scales within the outer scale,
divided according to a different unit or different units of measure, and an index or
pointer pivoted concentric with the disc, wheel, or roller, having its lower arm
weighted and pointed, and extending to the outer scale, and its upper arm made
light, narrow and pointed, and extending to the inner scale or scales, for the purpose
specified.
3. The combination, substantially as hereinbefore set forth, of the bushing or core,
the circular, graduated plates on each side of the bushing, and beveled on their
inner sides at the periphery, the tire or rim of soft. flexible material between the
plates and around the bushing or core, and extending beyond the edges of the plates;
the bosses of the bushing extending centrally through the plates, the axle or shaft, the
frame to which it is secured, and an index or pointer, pivoted concentric with the
circular, graduated plates.
4. The combination, substantially as hereinbefore set forth, of the central bushing
or core, its laterally projecting bosses having the extensions a³, the metallic plates
secured to the bushing around the bosses, and having their inner sides tapered or
beveled, as described, and marked on their outer sides with scales divided in
accordance with suitable units of measure, the tire or rim of soft, flexible material
secured around the bushing and between the plates, and extending beyond the outer
edges or peripheries of the plates, the frame, its handle, the axle secured to the frame
and extending through the bushing and its extensions, and the indexes or pointers
pivoted on the extensions a².
5. The combination, substantially as hereinbefore set forth, of the disc, wheel, or
roller, having a circular scale on its side and around its periphery, divided into inches,
and a circular scale within the outor scale, divided proportionately to represent miles,
the frame to which the disc, wheel, or roller is pivoted, and the freely suspended
pointers or indexes adjacent to the disc, wheel, or roller.
Dated this 2nd day of March 1889.