IMPROVED THERMOMETER."
Year: 1881

page_text: PROVISIONAL SPECIFICATION left by the said Moritz Immisch at the
Office of the Commissioners of Patents on the 6th July 1881.
MORITZ IMMISCH, of Highgate Road, in the County of Middlesex.
IMPROVED THERMOMETER."
"AN
My Invention relates especially to thermometers to be used for clinical purposes
where smallness and handiness are requisite, and it consists essentially in the
employment of a volute tube acting on the Bourdon principle, which tube is caused
to give motion to a pointer or band by being filled with a highly expansive fluid,
such as ether or alcohol, expanding in heat and contracting in cold.
The tube has a suitable number of turns, and may be fixed either at its inner or
at its outer end. When the tube is fixed at its inner end, the outer or free end acts
upon a rack which gears with a pinion, the spindle of which carries the pointer or
hand. By way of connecting the extremity of the tube with the rack, the former
is provided with a pivot corresponding to a jewel hole fitted to the end of a flat
spring which is screwed on the face of the rack. The flat spring has slots cut into
it, so as to allow it to be shifted for the purpose of adjusting the motion of the
rack. The axis of the rack carries a weight or counterpoise, which serves to
properly poise the system in the vertical positions. The centre pinion carrying the
hand or pointer is fitted with a hair spring, which serves, in the first place, to keep
the teeth of the pinion well against those of the rack; and secondly, as its force is
opposed to the action of the tube, it serves to effect the final adjustment.
When the outer end of the volute tube is fixed, an intermediate rack is employed,
against the side of which the free or inner end of the tube abuts, either simply by
means of an upright pin, or by means of a pivot and hole. This rack communicates
its motion to a pinion fitted to a second rack gearing with the centre pinion
carrying the indicating hand or pointer. A counterpoise on the rack and a hair
spring on the centre pinion are provided, as in the first arrangement.

page_text: The whole of the mechanism is enclosed in a suitable metal case provided with a
suitably divided face, and covered with a glass or crystal.
In some cases the volute tube may be exhausted of air and hermetically sealed,
and the surrounding space of the case, which latter is rendered air-tight, may be
filled with a highly expansive and heat absorbing vapour, which being acted upon
by heat would expand and compress the tube, the mechanical arrangements being
similar to those above described. In this case the instrument would be specially
adapted for surface temperatures, and the enclosing case would be partly of silver
and partly of a non-conducting material.
In each case means are provided by which the hand or pointer may be fixed
after a temperature has been taken or registered.
The bow or handle of the instrument is made movable, permitting a motion of a
quarter of a turn. The pivot of the stem reaches into the inside of the case and
carries an eccentric, against the circumference of which rests a spring fixed to the
bottom surface of the plate carrying the whole mechanism. This spring is fitted
with a jewel end stone, upon which the spindle of the centre pinion carrying the
indicating hand or pointer runs. When the bow or handle is turned upright the
eccentric permits the spring to rise, in doing which it lifts the pinion and presses
its face against the face of the bracket in which the top end of the spindle revolves.
The friction thus produced resists the motion of the tube and fixes the indicating
hand or pointer. On turning the bow or handle back a quarter of a turn, the
eccentric forces the spring downwards and the pinion is instantly released.
The stopping of the hand or pointer may also by any simple contrivance be
varied so as to take place laterally instead of longitudinally by an arm or spring, or
arms or springs, pressing against a disc fixed for that purpose on the centre pinion
spindle.
The bow is split so as to allow a long handle to be introduced and screwed into
the stem if required.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed
by the said Moritz Immisch in the Great Seal Patent Office on the 4th
January 1882.
MORITZ IMMISCH, of Highgate Road, in the County of Middlesex.
IMPROVED THERMOMETER."
"AN
My Invention relates especially to thermometers to be used for clinical purposes
where smallness and handiness are requisite, and it consists essentially in the
employment of a volute tube acting on the Bourdon principle, which tube is filled
with a highly expansive fluid, such as ether or alcohol, and by expanding in heat
and contracting in cold is caused to give motion to a hand or pointer.
The tube is surrounded by two upright strips of metal soldered or otherwise
fastened to the bottom of the case which encloses the whole. These two upright
strips thus form an open box within which the tube works and serves, in the first
place, to prevent the tube being bent by a violent shock; and secondly, to increase
the heating surface, thus rendering the instrument inore sensitive.
The tube has a suitable number of turns and may be fixed either at its inner or
at its outer end. When the tube is fixed at its inner end, the outer or free end
acts upon a rack which gears with a pinion, the spindle of which carries the
pointer or hand. By way of connecting the extremity of the tube with the rack
the former is provided with a pivot working in a hole, drilled in the outer
extremity of the rack at a suitable distance from the fulcrum of the same.
spindle of the centre pinion carrying the hand or pointer is fitted with a hair
spring, which serves, in the first place, to keep the teeth of the pinion well against
those of the rack; and secondly, as its force is opposed to the action of the tube it
serves to effect the final adjustinent.
The
When the outer end of the tube is fixed, an intermediate rack may be employed,
against the side of which the free or inner end of the tube abuts, either simply by
means of an upright pin or by means of a pivot and hole. This rack_communicates
its motion to a pinion fitted to a second rack gearing with the centre pinion carrying
the indicating hand or pointer. A hair spring on the spindle of the centre pinion
is provided as in the first arrangement.
The whole of the mechanism is enclosed in a suitable metal case provided with
a suitably divided face and covered with a glass or crystal. The tube and the
inside of the case is covered by a film of a highly absorbent substance, such as
gum or alum, which covering assists radiation and renders the action of the
instrument more prompt.
In some cases the volute tube may be exhausted of air and hermetically sealed,
and the surrounding space of the case, which latter is rendered air-tight, may be
filled with a highly expansive and heat absorbing vapour, which being acted upon
by heat would expand and compress the tube; or the condition of things may be
reversed by filling the tube with the vapour and rendering the surrounding space
void of air. This plan is preferable for instruments intended to register surface
temperatures. The mechanism is fixed on a silver plate which is the part coming
in contact with the surface to be examined, and the rest of the case may be made
of a non-conducting material in order to neutralize or minimize the effect of the
varying temperature of the atmosphere. This end may also be gained where the
whole of the case is made of metal, by covering the tube and the inside of the open
box referred to above by a highly absorbent substance, such as gum or alum, and
leaving the outside of the box and the rest of the case brightly polished. The
mechanical arrangements are similar to those above described.
Means may be provided by which the hand or pointer may be fixed after a
temperature has been taken.
The bow or handle of the instrument is made movable, permitting a motion of

page_text: a quarter of a turn. The pivot of the stem reaches into the inside of the case and
carries an eccentric, against the circumference of which rests a spring fixed to the
bottom surface of the plate carrying the whole mechanism. This spring is fitted
with a jewel end stone upon which the spindle of the centre pinion carrying the
indicating hand or pointer runs. When the bow or handle is turned upright the
eccentric permits the spring to rise, in doing which it lifts the pinion and presses
its face against the face of the bracket in which the top end of the spindle revolves.
The friction thus produced resists the motion of the tube and fixes the indicating
hand or pointer. On turning the bow or handle back a quarter of a turn, the
eccentric forces the spring downwards and the pinion is instantly released.
The stopping of the land or pointer may also by any simple contrivance be
varied so as to take place laterally instead of longitudinally, by an arm or spring,
or arms or springs, pressing against a disc fixed for that purpose on the centre
pinion spindle.
The bow is split so as to allow a long handle to be introduced and screwed into
the stem if required.
The instrument may be rendered self registering by fitting a ratchet wheel with
very fine teeth to the spindle of the centre pinion. A pawl or click pressed lightly
against the wheel by a hair spring prevents the hand from going back till the
wheel is released by lifting the click, which may be done by means of a push piece
or other suitable means.
With self registering instruments it is advisable to make the outer extremity of
the rack inovably connected with the tube, in such a manner that ordinarily it
would be held in its place by a sprial spring fitted to the spindle of the rack, the
movable piece abutting against a pin fixed in the body of the rack. When the
temperature has attained its greatest height, the pawl or click prevents the centre
pinion moving back, but the tube in receding carries the movable piece with it and
on releasing the ratchet wheel the spiral spring forces the hand to its proper
position. By means of this arrangement the pressure against the pawl or click can
never be greater than that resulting from the force of the spiral spring.
But in order that my Invention may be more clearly understood, I will proceed
to describe the same by the aid of the accompanying Sheet of Drawings, in which
Fig. 1 is a plan view of the instrument in which the inner end of the volute tube
is fixed; Fig. 2 is a transverse section of the same; Fig. 3 is a plan of the
instrument in which the outer end of the volute tube is fixed; Fig. 4 is a transverse
section of the same; Figs. 5 and 6 are vertical sections through Figs. 1 and 3,
showing one arrangenient for fixing the hand or pointer after a temperature has
been taken or registered; Fig. 7 is a plan; Figure 8, a transverse section; and Fig. 9,
a vertical section showing another arrangement for fixing the hand or pointer after
a temperature has been taken or registered.
Referring to Figs. 1 and 2, A is the volute tube filled with a highly expansive
fluid, such as ether or alcohol expanding in heat and contracting in cold. This
tube is fixed at its inner end, and its outer or free end acts upon a rack B which
gears with a pinion C, the spindle of which carries the pointer or hand D. The
free end of the tube A is connected to the rack B by means of a pivot E secured
to the former and working in a hole drilled in the latter. The spindle which
carries the hand or pointer D is fitted with a hair spring H which serves, in the
first place, to keep the teeth of the pinion C well against those of the rack B; and
secondly, as its force is opposed to the action of the tube A, it serves to effect the
final adjustment.
Referring to Figs. 3 and 4, in which the outer end of the volute tube A is fixed,
an intermediate rack I is employed, against the side of which the free or inner end
of the tube A abuts, cither simply by means of an upright pin as shown, or by
means of a pivot and hole as in the first arrangement above described. This rack I
communicates its motion to a pinion K fitted to a second rack B gearing with the
centre pinion C, the axis of which carries the indicating hand or pointer D. A hair
spring His provided on the axis of the centre pinion as in the first arrangement.

page_text: In both these arrangements the tube A is enclosed in an open box formed by the
two metal strips F secured to the case, and serving, first, to prevent the tube being
bent by a violent shock; and secondly, to increase the heating surface.
The whole of the mechanism is enclosed in a suitable case L provided with a
suitably divided face and covered with a glass or crystal.
Referring to Figs. 5 and 6, one arrangement is shown for fixing the hand or
pointer after a temperature has been taken or registered. The bow or handle M of
the case is made movable permitting a motion of a quarter of a turn. The pivot of
the stem reaches into the inside of the case L and carries an eccentric N against the
periphery of which rests the free end of a spring O fixed to the bottom surface of
the plate P carrying the whole mechanism. This spring is fitted with a jewel
end stone upon which the spindle of the centre pinion C carrying the indicating
hand or pointer D runs. When the bow or handle M is turned upright tho
eccentric N permits the spring O to rise, thereby lifting the pinion C and pressing
its face against the under side of the bracket Q in which the top end of the spindle
revolves. The friction thus produced resists the motion of the tube and fixes the
indicating hand or pointer. On turning the bow or handle M back again, the
eccentric N forces the spring O downwards, and the pinion is instantly released.
Referring to Figs. 7, 8, and 9, in which another arrangement is shown for fixing
the hand or pointer after a temperature has been taken or registered, a ratchet
wheel S having very fine teeth is fitted to the spindle of the centre pinion C.
A pawl or click T pressed lightly against the wheel S by a hair spring U prevents
the hand from going back till the wheel is released by lifting the click or pawl T
out of gear, either by means of the push piece V or by any other suitable means.
With self registering instruments it is advisable to make the outer extremity
of the rack B movably connected with the tube A in such a manner that ordinarily
it would be held in its place by a spiral spring W fitted to the spindle of the rack.
For this purpose the free end of the tube A is connected by a pivot and hole to a
movable piece X mounted loosely on the rack spindle and held in place by the
spiral spring W, so as to abut against a pin Ỷ fixed in the body of the rack.
When the temperature has attained its greatest height the pawl or click T prevents
the centre pinion moving back, but the tube A in receding carries the movable
piece X with it, and on releasing the ratchet wheel S the spiral spring forces the
hand to its proper position.
The bow or handle M is split so as to allow a long handle R to be introduced
and screwed into the stem if required.
Having now described the nature of my Invention and the manner of carrying
the same into effect, I wish it to be understood that what I claim is,―
First. The construction of the improved thermometer, substantially as herein
described and shown in the Drawings, the essential feature of which consists in
the employment of a volute tube, either filled with a highly expansive fluid, or
exhausted of air, and the surrounding space of the case filled with a highly
expansive and heat absorbing vapour, the expansion and contraction of which
volute tube is caused by suitable mechanism to move a hand or pointer over a
suitably divided face.
Second. The modes of fixing the hand or pointer after a temperature has been
taken, substantially as herein described.
In witness whereof, I, the said Moritz Immisch, have hereunto set my hand
and seal, this Fourth day of January, in the year of our Lord One
thousand eight hundred and eighty-two.
MORITZ IMMISCH. (L.S.)