An Improved Instrument for Measuring Distances on Maps.
Year: 1897

page_text: Date of Application, 11th Dec., 1897
Complete Specification Left 10th Sent 1898-Accepted. 22nd Oct.. 1898
PROVISIONAL SPECIFICATION.
An Improved Instrument for Measuring Distances on Maps.
I, JAMES HUNTER GRAY, of 141, Hopton Road, Streatham, Bachelor of Science,
do hereby declare the nature of this invention to be as follows:-
are
The object of my invention is to provide a curvimeter which is capable of being
adjusted so as to measure distances on maps in which the scales are different.
For this purpose I employ a measuring wheel which travels over the surface of
the map, and a registering wheel. The measuring wheel is preferably spurred,
so that there is no risk of slipping. The registering wheel las teeth round its
periphery, and is so arranged that the measuring wheel causes it to revolve through
a space equal to the distance between two of its adjacent teeth every time that
the two wheels gear with each other. The method which I employ for gearing
the two wheels is as follows:-The measuring wheel is provided at calculated
points with pins projecting laterally, and the registering wheel is so placed that
one or more of these pins actuate the teeth of the latter, which thereby revolves.
The registering wheel is graduated so that the distance measured can be read off.
For example, I may apply my invention so as to be adjustable to the following
four scales; one inch, half inch, quarter and eighth inch to the mile. In such an
instrument, a convenient size for the measuring wheel is such that the circumference
is exactly one inch. All the pins can be arranged on the side of the measuring
wheel so as to be at an equal distance from the centre of the wheel.
The pins are of different lengths, and since they at equal dis-
tance from the centre, the registering wheel need only be constructed
be
movement in
direction
to
the
of its axis,
so that it can be made to come in contact with one or more of the pins of the
measuring wheel as may be desired. If the pins are not all at equal distance
from the centre the registering wheel must be capable of adjustment so as to
come in contact with every one of the pins. For example, when the scale is
one inch to the mile the registering wheel would be adjusted so as to come in
contact with only one pin, namely the longest, for each revolution of the
measuring wheel. If the scale is half inch to the mile, the registering wheel is
adjusted so as to come in contact with two pins every revolution, namely the
longest and the next longest, which should be situated diametrically opposite; the
registering wheel then travels through two of its teeth for one revolution of
the measuring wheel. If the scale is quarter inch to the mile, it is clear that
it is only necessary to adjust so that four of the pins actuate the registering
wheel for each revolution of the measuring wheel; and for a scale of eighth inch
to the mile, eight pins actuate for each revolution. When the curvimeter has
traversed the distance on the map which it is desired to measure, it is only
necessary to take the reading on the registering wheel, if the latter was set so as
to start from zero.
So
as
capable of
I may arrange a small metal or other tongue so that the teeth of the registering
wheel cause it to emit a sound every time a tooth passes, thereby indicating the
distance traversed. I may dispense with the registering wheel when this tongue

page_text: is used, and arrange that the latter is actuated directly by the pins of the measur-
ing wheel and that it is capable of adjustment so as to come in contact of one or
more of the pins according to the scale in manner similar to that already described
in connection with the registering wheel.
111
P
I, JAMES HUNTER GRAY, of 141, Hopton Road, Streatham, London, Barrister-
at-law, 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 curvimeter which is capable of being
adjusted so as to measure distances on maps in which the scales are different.
For this purpose I employ a measuring wheel, which travels over the surface of
the map, and a registering wheel. The measuring wheel is preferably spurred,
so that there is no risk of slipping. The registering wheel las teeth round its
periphery, and is so arranged that the measuring wheel causes it to revolve through
a space equal to the distance between two of its adjacent teeth every time that
the two wheels gear with each other. The method which I employ for gearing
the two wheels is as follows:-The measuring wheel is provided at calculated
points with pins projecting laterally, and the registering wheel is so placed that
one or more of these pins actuates the teeth of the latter, which thereby revolves.
The registering wheel is graduated so that the distance measured can be read off.
For example, I may apply my invention to an instrument so as to make it adjust
able to the following four scales;-1 inch, inch, inch, & inch to the mile. In such
an instrument, a convenient size for the measuring wheel is such that the circum-
ference is exactly one inch. All the pins can be arranged on the side of the measuring
wheel 80 as to be at an equal distance from the centre of the wheel.
The pins are of different lengths, and, since they are at equal dis-
tances from the centre, the registering wheel need only be constructed
SO as to be capable of movement in the direction of its axis,
so that it can be made to come in contact with one or more of the pins of the
measuring wheel as may be desired. If the pins are not all at equal distances
from the centre, the registering wheel must be capable of adjustment so as to
come in contact with every one of the pins. For example, when the scale is
one inch to the mile, the registering wheel would be adjusted so as to come in
contact with only one pin, namely the longest, for each revolution of the
measuring wheel.
If the scale is inch to the mile, the registering wheel is
adjusted so as to come in contact with two pins every revolution, namely the
longest & the next longest, which should be situated diametrically opposite; the
registering wheel then travels through two of its teeth for one revolution of
the measuring wheel. If the scale is inch to the mile, it is clear that
it is only necessary to adjust so that four of the pins actuate the registering
wheel for each revolution of the measuring wheel; and for a scale of inch
to the mile, eight pins actuate for each revolution.
When the curvimeter has traversed the distance on the map which it is desired
to measure, it is only necessary to take the reading on the registering wheel, it
the latter was set so as to start from zero.
I may arrange a small metal or other tongue so that the teeth of the registering
wheel cause it to emit a sound every time a tooth passes, thereby indicating the

page_text: distance traversed. I may dispense with the registering wheel when this tongue
is used, and arrange that the latter is actuated directly by the pins of the measur-
ing wheel, and that it is capable of adjustment so as to come in contact with one or
more of the pins according to the scale, in manner similar to that already described
connection with the registering wheel.
Figures 1, 2 & 3 show in detail an instrument made according to my invention,
Figure 1 being a section through the axes of the wheels, Figure 2 a plan, &
Figure 3 a plan in which one of the bearing plates is removed so as to show the
wheels and the tongue.
A is the measuring wheel having two pins B & C projecting from one of its
sides, B being somewhat longer than C. For the sake of simplicity, only two
pins are shown in the drawings, and this would only provide two different scales,
but it is obvious that, by increasing the number of pins, the number of different
scales can be similarly increased. D is the registering wheel rotating on an axis
parallel to the axis of A, & being arranged so that the teeth on its periphery gear
with the pins B & C. The axis of 1) at one end rotates in the adjustable centre E,
and is kept against E by the spiral spring F. G is a flexible sounding tongue
arranged so as to lie normally between the teeth of D), so that, as 1) rotates, G emits
a sound each time that a tooth of D) passes across it. HH are the bearing plates
in which the wheels A & D work. I is a convenient form of handle for the
instrument.
It will be obvious that, if the registering wheel D is in the position shown in
Fig. 1, only the longer pin B will gear with it, but by screwing the adjustable
centre forward sufficiently, D will be made to gear also with C, & the smaller scale
will then be obtained. The wheel 1 may be graduated on one or other side to
enable the distance measured to be read off, or the flexible tongue may be used
to sound the distance, or both may be used.
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 instruments for measuring distances on maps, arranging pins of different
lengths on either side of the measuring wheel whereby the registering mechanism
can be actuated so as to be capable of registering in two or more different scales.
2. In instruments for measuring distances on maps, arranging pins of different
lengths on either side of the measuring wheel, whereby a graduated registering
wheel can be actuated so as to be capable of registering in two or more different
scales substantially as described.
3. In instruments for measuring distances on maps, arranging pins of different
lengths on either side of the measuring wheel whereby a registering wheel can be
actuated so as to be capable of measuring two or more different scales, and
indicating the same on a flexible sounding tongue substantially as described.
4. An instrument for measuring two or more different scales on maps sub-
stantially as described & illustrated in the accompanying drawings.
Dated this 10th day of September 1898.