Improvements in Automatic Recording Thermometers.
Year: 1897

page_text: Date of Application, 16th Nov., 1897
Complete Specification Left, 14th Sept., 1898-Accepted, 16th Nov., 1898
Improvements in Automatic Recording Thermometers.
I, MELVILLE LINCOLN WILKINSON, of 84 and 85, Bryron Building, Los Angeles,
in the State of California, United States of America, Engineer, do hereby declare
the nature of this invention to be as follows:-
This invention which relates to improvements in automatically recording ther-
mometers is more especially adapted for clinical use, and has for its object to
enable a diagram to be taken indicating the variations in temperature of a
patient or sick person over any desired period, for example, during a few minutes,
an hour, or for several hours, as may be necessary.
The apparatus constituting my invention consists of a metal case, the metal
used for the construction of the case being preferably aluminium. This case
is of rectangular form and otherwise generally of such shape and dimensions
that it can be conveniently applied to the more especially warm parts of the
human body, such for example, as the arm-pits or anywhere between or upon
the limbs or abdomen, and it may be made small enough to be placed in the
mouth of the patient whose variations in temperature over any period it is desired
to record.
The moving parts of the instrument consist of a series of bars formed of two
substances which have different coefficients of expansion. This series of bars is
so arranged that whilst the first of the series is rigidly fixed at one end to the
casing containing the moving parts of the instrument, the lengthening of a bar
by any increment of heat which it receives from the body of the patient, moves
the rest of the series of bars through a distance corresponding to its own incre-
ment of length due to expansion; and alternatively, any abstraction of heat from
the said bar due to a lowering of temperature, causes the said bar to shorten,
thereby moving the whole series of bars backwards through a distance corre-
sponding to its decrement of length due to contraction.
As the extent of motion of any bar of so short a length as can be practically
used in an instrument of the kind here referred to, is small, it follows that in
order to effect a sufficient range of movement for the purpose of obtaining the
necessary indication, a series of bars placed parallel to each other and held
together at their ends by bars of material having less expansibility than the
material used for the set of bars first referred to, will add the motion of its own
expansion or contraction of each succeeding bar to the sum of the several expan-
sions or contractions of the preceding bars of the series, less the sum of the
differences due to the smaller expansion of the metal constituting the second
series of bars.
In this way by means of such an arrangement as that described in the preced-
ing paragraphs it follows that with a series of short bars the sum of their
motions of expansion or contraction will produce a sufficient amount of move-
ment in either an expanding or contracting direction, which if applied to direct
the motion of a lever carrying a pencil, will cause that pencil to move through
an arc whose position at any moment in said arc is an exact indication of the
temperature of the patient or sick person, so that if the pencil point presses upon

page_text: a properly divided sheet of diagram paper slowly traveling in contact with the
pencil point, such pencil point will trace upon said traveling sheet of paper a
diagram which becomes a permanent record of the variations of temperature of
the patient or sick person over any desired period.
The apparatus herein-before described, is connected to a lever which in turn
operates another lever carrying a pencil which is moved over the face of the
traveling diagram sheet such as that hereinbefore referred to. The diagram
sheet is carried at one end upon a spring actuated roller; the other end of the
diagram sheet being connected to another cylinder which unwinds the diagram
sheet from the cylinder first referred to in doing so pulling against the tension
of a spiral spring by which the cylinder first referred to is operated. The last
mentioned cylinder is operated by means of clock mechanism contained within
the casing of the instrument having a main spring which is wound up periodi-
cally as required, constituting the motor which drives the clock mechanism,
and an escapement governed by a balance wheel which regulates the unwinding
of the clock gear and thereby the second cylinder herein before referred to.
Dated this 29th day of Oatahan 1007
MELVILLE LINCOLN WILKINSON.
Haseltine, Lake & Co.,
45, Southampton Buildings, London, W.C.,
Agents for the Applicant.
Improvements in Automatic Recording Thermometers.
I, MELVILLE LINCOLN WILKINSON, of 145, Spring Street, in the City and
County of Los Angeles, in the State of California, United States of America,
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;-
My said invention which relates to new or improved automatically recording
thermometers, whilst being more especially applicable for clinical use, is also
adapted for other purposes wherein it is required to record variations in tempera-
tures automatically and the object of my new or improved automatically record-
ing thermometers is to enable a diagram to be taken indicating (when employed
for clinical use) the variations in temperature of a patient or sick person over
any desired period, for example, during a few minutes, an hour, or for several
hours, as may be necessary.
In order that my invention may be fully understood, I have hereunto appended
two explanatory sheets of drawings in which:
Figure 1 is a vertical section of my improved automatically recording thermo-
meters taken on the line a a Figure 2.
Figure 2 is a transverse section of the same on the line 6 6 Figure 1.
Figure 3 is a vertical section of my improved automatically recording thermo-
meter taken upon the line c c Figure 4.
Figure 4 is a transverse section taken on the line d d Figure 3.
Figure 4 is a perspective view of one end of the bars D, and E, on an enlarged
scale, more especially showing the connection of the respective bars at the end
where they are joined together, and the joining screw.
Figure 5 is a horizontal section on the line e e
Figure 6 is a horizontal section on the line ff Figure 3.
Figures 3 and 4.
Figure 7 is a plan of one of the bars of least expansible material used in the
series of expanding and contracting bars.

page_text: 1
18 an edge elevation of Figure 7.
9 is a diagram on a reduced scale, showing the curve of temperatures
by my improved automatically recording clinical thermometer.
it is here explained that for the sake of perspicuity the instrument shown by
the annexed drawings is larger than it would be made for practical clinical
purposes; also that the diagram shown at Figure 9, whilst larger than the
diagram that would be obtained from the instrument of proper size for clinical
use is somewhat smaller than the diagram that would be obtained from an instru-
ment of the size shown on the drawings.
It is further explained that the improved automatically recording thermometer
may, when used for manufacturing processes or operations, or in the arts, or
for recording variations in atmospheric temperatures, be made considerably
larger then when used for clinical purposes.
In Figures 1 to 6 the box or casing of the instrument is marked A. This
is constructed with the covering B, at one side attached to the casing A by means
of a hinge C, so that the cover B, may be opened for the purpose of inserting the
diagram paper and for taking out the diagram from the interior thereof. Any
kind of spring latch or clasp may be used for keeping the lid or cover B, closed
upon the casing or box A.
At the upper end of the casing A, and at the back thereof, as shown at
Figures 1 and 2, a metallic bar D, is rigidly fastened by means of short project-
ing studs a, forming part of or fastened to the bar D. These studs x enter
corresponding holes in the side of the casing, as shown. The metallic bar D,
is formed with a hook at the left hand end thereof, as seen in Figure 1. This
bar D, is formed of a metal or alloy which has a very small coefficient of expan-
sion, for example, German silver. This bar D, constitutes the one fixed point
or portion of the thermometric system of bars which are used. In the hook
end of this bar D, one end of the bar E is fitted, and firmly secured thereinto,
not only by the hook formation of the bar D, in the manner shown, but also by
means of a screw g, shown in Figures 1 and 2, being passed through a hole in
the hook bar D), and tied in the end of the bar E. From this construction it
follows that when the bar E, is expanded or contracted by the addition or sub-
traction of heat, it increases or diminishes in length correspondingly, and by
reason of the bar E, having another bar D¹, of lower expansibility attached to
its right hand end, the bar E, when expanded or contracted, moves the bar D',
through the same range of motion, and in the same direction through which
the bar E, itself moves, corresponding to the variations in temperature. The
metallic bar D', of low expansibility, has another bar E¹, of high expansibility,
attached to it at its left hand end in the same manner that the preceding bars E
and D respectively, are attached together, and the bars of the entire series shown
in Figures 1 and 2, alternate in their construction and attachment in the same
manner, so that the net sum of the entire movements of the hars E, of the series
become added together in the last bar E. The movements of the last bar E,
expressing all the accumulated variations of temperature which have occurred
during the period of observation. The bars E, are preferably made of hard
rubber, for the reason that the larger coefficient of linear expansion which that
material possesses in comparison with the small coefficient of linear expansion
which the other bars D, of German silver or other metal or alloy possess. I
desire here to point out that I am aware that bars of metal of different expansi-
bilities by heat have been previously proposed to be used for producing thermo-
metric observations, but in all such cases, the pairs of bars used have been
united together at short distances apart throughout their entire length, so as
to produce, when heated or cooled, a curvature of each such pair of bars.
my system, however, the bars are not connected together in pairs, nor are they
in anywise attached together, except at their ends, so that each bar is free to
move, and can only move longitudinally, whilst constantly maintaining the
parallel positions of the several bars under the influences of variations in tem-
In

page_text: perature, and it is the net sum of these longitudinal and parallel mov
either direction, which is expressed in the last bar of the series, that o
the pencil of the diagram drawings mechanism.
In the lower chamber F, of the box A, clock driving gear is fitted, the purpose
of which is to very slowly rotate the diagram cylinder G. The particular con-
struction of the driving clock gear is no essential part of my invention and
therefore may be changed in any of the well known and commonly used varia-
tions of clock mechanism. The essential feature of the driving clock gear being
that of a main spring in the barrel, H, which can be wound up to acquire
potential and thence impart motion through a train of wheels such as that
shown in the drawings, to an escapement, I, and balance wheel, K, at the other
end of the train.
be seen.
Besides the barrel, G, operated by the aforesaid clock-work, the front part of
the casing contains another barrel, L, carried upon a fixed shaft, M, and
attached thereto by means of a spiral spring, N, shown in the interior of the
barrel, L, the upper part of which is broken away to enable said spring, N, to
One end of the diagram paper is attached to the spring barrel, L, by
means of a strip such as is common to the diagram barrels of indicating instru-
ments, and the tension of the spring, N, always tends to wind the diagram paper
upon the barrel, L. The other end of the diagram paper, O, is attached to
the barrel, G, by a similar fastening strip, and when the instrumes is in
operation, the slow movements of the barrel, G, actuated by the clock-work,
causes the barrel, G, to wind the diagram paper, 0, on to itself and from
the barrel L, at a sufficiently slow progressive rate.
The
The lowest bar, E, of the series of hard rubber bars, rests upon rollers, P,
whereby it is enabled to move backwards and forwards with freedom, and its
right hand end has a connecting piece, Q, attached to it by a pin, R. The
outer end of the connecting piece, Q, is formed with a slot, as shown at Figs. 1
and 3, which engages with the pin S, in the lower arm of the lever, T.
lever, T, in its normal position rests at its upper end against an adjustable
stop, U, being pulled by means of the light spiral spring, W. The upper end
of the lever, T, engages with the lever, X, carried upon the shaft, X', and upon
the shaft, X, there is also attached the long lever, Y, which is formed as a
light spring carrying at its outer end the pencil, Y', whose point presses against
the slowly transversing diagram sheet, O.
This arrangement, it will be seen that any motions of the series of bars cor-
responding to the increment of temperature, will move the connection, Q, in
the direction of the arrow, h, Figs. 1 and 2; whilst any decrement of temperature
will move the connecting piece, Q, in the opposite direction. As any move-
ment of the connecting piece, Q, in the direction of the arrow, h, causes the
lower end of the lever, T, to move on its axis in the opposite direction and to
stretch the spring, W. The lever, X, being engaged with the upper end of the
lever, T, as shown at Fig. 3, is also moved in the same direction and to the
same extent as the lever T, thereby moving the shaft, X', upon its axis and
correspondingly therewith causing the lever, Y, and pencil, Y¹, to be moved
upwards on the face of the diagram paper. The movements of the several parts
whereby the diagram is drawn on the paper, O, is indicated by the several
dotted lines and circular arcs in Fig. 3. When the observation has been taken,
the variations of the movement of the pencil point, brought about in the
manner and by the means of the instrument hereinbefore described, is drawn
as an irregular curve, i, upon the diagram sheet as indicated in Fig. 9, wherein
the horizontal lines indicate temperatures and the segmental lines indicate hours.
In order that the levers, T and Y, may not be moved to an abnormal extent,
a stop, j, is provided against which the lever, T, presses when it is moved to
its maximum range. And to further prevent any fracture or injury to the
instrument which might take place through the further movement of the last
bar, E, of the series tending to push the lever, T, beyond this point, the lower

page_text: Figure lever, T, is made separate from the upper part and movable around
takere axis, T¹, being pressed and maintained in its normal position by the
Epring, T, as shown at Fig. 3. This arrangement enables the lower part
of the lever, T, to be moved beyond its normal position in such case, by reason
of the yielding of the spring, T", which forces the lower part of the lever, T,
back to its normal position so soon as the abnormal temperature is removed.
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:-
-
First: The automatically recording thermometer consisting of a box or case
containing a series of parallel bars, moving, or sliding longitudinally and
always in parallel to one another, fastened together at their ends only and
alternately made of substances having different expansibilities, such as German
silver and hard rubber, one end of the series of bars being fixed to the casing
enclosing the apparatus, and the other end of the series of bars being supported
on rollers so as to leave the entire series of bars free to move backwards and
forwards longitudinally, corresponding with variations in temperature to which
the series of bars is subjected, the said bars being always maintained and
moving in parallel and sliding contact with each other, the movable end of
the series of bars being connected to lever mechanism carrying a pencil point
whereby the ultimate motion of the series of bars corresponding to the variations
of temperature, are inscribed upon a sheet of slowly moving diagram paper,
actuated by clock-work, all operating together in the manner and for the
purposes substantially as set forth.
Second: The combination of the series of bars formed alternately of
materials having different expansibilities, always maintained and moving longi-
tudinally in parallel and sliding contact according to the variations in tempera-
ture, the bar forming one end of the series being fixed to the casing of the
instrument, whilst all the other bars are free to move from said fixed point
longitudinally and parallel, thereby imparting their sliding movement to all
the succeeding bars of the series, the net sum of the motions of any preceding
bars of the series so imparted to any succeeding bar or bars of the series being
such that the longitudinal parallel movement of the last bar of the series so
moved. is equal to the net sum of the longitudinal movements of itself and all
the other preceding bars of the series so moved, less the difference in longi-
tudinal movement of the sum of the other bars of the series having least expan-
sibility. said alternate bars of different expansibility being connected together
at their ends substantially as set forth.
Third: The combination of the series of bars connected together at their
ends and formed alternately of materials having different expansibilities, the
rollers, the connecting piece, the lever to which the connecting piece from the
last bar imparts the movement of the series of longitudinally moving parallel
bars, the spiral spring, the lever on the shaft to which the pencil-carrying lever
is attached, the rvlinders or drums carrying the diagram paner, the clock
driving gear and the drum whereby the diagram paper is unwound, all operating
together in the manner and for the purposes substantially as set forth.
Dated thin 14+1
Contamhon 1000
HASELTINE, LAKE & Co.,
45, Southampton Buildings, London, W.C.,
Agents for the Applicant.