Improvements in a Registering Thermometer.
Year: 1887

page_text: Date of Application, 31st Aug., 1887
Specification Accepted, 14th Oct., 1887
Improvements in a Registering Thermometer.
A communication from abroad by DANIEL DRAPER, of Hastings, Westchester County,
State of New York, United States of America, Meteorologist.
I, WILLIAM PHILLIPS THOMPSON F.C.S. M.I.M.E. of the. Agency for Foreign
Patent Solicitors, 6 Lord Street, Liverpool, and 6 Bank Street, Manchester, both in
the County of Lancaster, and 323 High Holborn, in the County of Middlesex, 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 class of apparatus employed for giving a continuous
register of the variations in temperature at any given point, and the object of the
invention is to provide simple and efficient means for giving a permanent record which
is exposed to view at all times during the period covered by the record card.
The invention consists, in general terms, in placing upon a suitable arbor driven at
a constant speed by a clock train a record card, divided into sections by lines
radiating from the center, for days and hours, and by concentric circles for the
different degrees of temperature. Upon this card there rests a recording pen which
is carried upon an arm moved toward and from the center of the card by the effects
of variations in the temperature, upon four thermostatic strips suitably connected
with the arm. These are connected in pairs arranged to operate in harmony with
each other, so that the movement of the arm is the joint result of both pairs. One
pair alone may be used, whenever desired, with excellent effect.
The strips are provided with suitable screws for adjusting the leverage.
The entire device is supported in a perforated case, which allows the air to circulate
freely about the thermostatic strips. The case is preferably supported upon yielding
springs, which prevent the arm from being moved by blows or accidental movements
of the support carrying the case. This is of special importance when the instrument
is used upon vessels or vehicles in motion. For the purpose of preventing the
thermostatic strips from being effected by moisture and exposure to the atmosphere,
they are preferably plated with nickle or gilded.

page_text: The invention will be described in detail in connection with the accompanying
drawings, in which figure 1 is a front elevation, partly in section, of the device, and
figure 2 is a transverse section of the same.
Referring to the figures, A represents a frame, preferably of cast-iron, for
supporting the case or box B. The sides of this box are perforated, to allow air to
circulate freely within. The frame A is supported upon yielding springs a a, which
prevent shocks or jars from being communicated to the recording-pen. A suitable
clock mechanism, preferably an eight-day movement, or even of greater capacity, is
contained in a box B₁ inside the case B. Upon the hour-hand b, of this clock frame,
there is carried a plate C. This plate carries at its center a pin c, and at a point a
little remote from the center a second pin c¹, and also at its edge three or more
clips c², c³, c. These are designed to hold the chart D, upon which the record is
made. This chart is adapted to receive a record of the variations in the temperature
for a period of one week. When the chart is to be put upon the plate, the central
pin is pushed through the central point of the chart, and the edges of the chart are
slipped under the clips, while the pin prevents the chart from being turned.
Radial lines d, d, divide the chart into divisions representing the days of the week,
and intermediate lines d¹, d, divide it into hours. Concentric lines divide the chart
into other divisions serving to indicate different degrees of temperature. The lines d d
and d d are preferably curved to correspond with the arc described by the arm F
when it turns upon its center of support. This arm F carries at its end a recording-
pen. It is designed that a sufficient quantity of ink to give the record for any
desirable length of time, shall be placed in this pen, and it will feed as required.
The arm F is more or less resilient, and presses lightly against the surface of
the chart.
The arbor is carried in a suitable frame or yoke G supported from the base of
the case B. The recording-arm F is fastened upon this arbor in a suitable manner,
preferably by a yoke, as indicated at f².
The two ends of the arbor bear in suitable journals or openings in the yoke. It
carries two levers H1, H2, terminating in widening curved ends. The face of these
ends or ares are recessed, and receive thin wires or cords h¹ and h² respectively. The
wire is fastened at one end to a thermostatic strip K¹, and passes across the face of
the arc, from which it is carried to and around a screw or pin k¹, and from this point
around the other end of the lever H¹ to the end of a second thermostatic strip K.
The two free ends of these strips K and K' are thus bent towards each other by
means of this wire, and any movement of one is necessarily communicated to the
other. The other ends of the two strips K1, K2, are rigidly attached to suitable
supports in the case B, upon opposite sides of the clock train. The strips are
constructed in any well known manner, of two metals brazed, soldered, or otherwise
fastened together, and they are so placed with reference to each other that any
variation in temperature will cause the free ends of both strips to move in the same
direction. Two other strips K³, K, similar to the strips K¹ and K2, are connected
with each other by a wire h2, and with the lever H2, which is similar to the lever H',
in precisely the same manner, being passed twice across the face of the lever and
wound about the pin or screw k². These two strips are supported in the same manner
as the strips K and K2, and are placed upon opposite sides of the arbor g; but the
sides of the strips presented to the arbor are the reverse of the strips K' and K², for
the reason that the lever H2 projects from the side of the arbor opposite to the lever H'.
In this manner the four strips combine to move the arbor in the same direction under
the influence of any variations in temperature. In order that the four thermostatic
strips may operate in perfect unison, and the maximum effect of their combined
action be secured, it is important that both their leverage and the tension of the wires
be properly adjusted. For adjusting the leverage the screws N¹ and N2 are placed at
the ends respectively of the strips K and K³. The ends of the wires are looped about
these screws, in the grooves n' and n², so that turning the screws docs. not change the
length of the wires, but changes the points in the lengths of the strips at which the
wires are attached, and thus adjusts the leverage. For the purpose of adjusting

page_text: the tension of the wires and equalizing the same between the two pairs of strips, the
adjusting screws m¹ and m³ are placed respectively at the ends of the strips K and K*.
These turn in the frame m and m² as shown in the figures, and their operation will be
easily understood.
The front of the case may be closed by a glass plate in any suitable manner.
It is evident that one pair of strips will operate precisely as both pairs, and one
pair may be used instead of both in many cases. The cost of the instrument is
thereby reduced.
Single thermostatic strips have been heretofore employed for moving a recording
lever, but the employment of two strips simplifies the instrument, and makes it more
perfect in operation. The use of four strips arranged in pairs as shown, is a further
improvement, giving greater permanence to the adjustment, and greater certainty in
the operation and result.
Having now particularly described and ascertained the nature of this said inven-
tion and in what manner the same is to be performed, as communicated to me by
my foreign correspondent, I declare that what I claim is :-
1. In a recording thermometer, the combination with a clock movement and a
chart carried thereby of two thermostatic strips, a recording lever, and a mechanical
connection between said lever and both of said strips.
2. In a recording thermometer, the combination of two thermostatic strips, a
recording dial and means for revolving the same at a constant rate, of a recording
arm applied thereto, an arbor carrying the same, a lever having its face formed in
the are of a circle, a wire or other mechanical connection having its ends brought
over the face of said lever and fastened to the respective thermostatic strips, sub-
stantially as described.
3. The combination in a recording thermometer of four thermostatic strips, a
recording-lever, a mechanical connection between two of said strips and said lever,
and an independent connection between the remaining two of said strips and said
lever.
4. The combination in a recording thermometer of a recording-arm, a thermostatic
strip, a cord or wire connecting said strip and recording-arc, and an adjusting device
upon said strip consisting of a screw N₁, having the groove n³ for changing the point
of connection in the length of said strip with said cord or wire.
5. The combination, in a recording thermometer, of the four bi-metallic strips
K', K, K³ and K4, the segments or levers H1, H2, the cords h², the adjusting
screws N¹ N2, m¹, m³, the frame A the perforated case B and the supporting
springs a a.
DL1 L. DAIL 1
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