IMPROVEMENTS IN BAROMETERS, WHICH INVENTION IS ALSO APPLICABLE TO T TY 11 3011
Year: 1881

page_text: LETTERS PATENT to Friedrich Hermann Felix Engel, Civil Engineer and
Patent Agent, in the City of Hamburg, Germany, for an Invention of
"IMPROVEMENTS IN BAROMETERS, WHICH INVENTION IS ALSO APPLICABLE TO
T
TY 11 3011
2
11
PROVISIONAL SPECIFICATION left by the said Friedrich Hermann Felix
Engel at the Office of the Commissioners of Patents on the 21st February
1881.
FRIEDRICH HERMANN FELIX ENGEL, Civil Engineer and Patent Agent, in the
City of Hamburg, Germany. "IMPROVEMENTS IN BAROMETERS, WHICH INVENTION
IS ALSO APPLICABLE TO MANOMETERS." A communication from Johann Diedrich
Möller, of Wedel, in the Dukedom of Holstein and Kingdom of Prussia.
This Invention relates to a new and very. simple mechanism for transporting the
movements of the diaphragm or diaphragms of the box of an aneroid barometer or
a manometer to the indicating hand of the instrument. The box of such instru-
ment may be composed of several boxes attached one to the other for the purpose
of enlarging the movements of the diaphragm.
The mode of transporting the movements (the play) of the uppermost diaphragm
of the box to the indicating hand consists of attaching a shaft or axle to the hand,
which axle reaches down towards the box, and is furnished at the bottom and
with a very steep screw thread cut in or formed to it. This thread passes through
a nut fastened to the diaphragm. The shaft or axle is kept in position by bearings
supporting the both ends, or by one top bearing and a spring.
When the diaphragm works up or down, according to the change of pressure, the
nut slides up or down on the thread of the shaft and turns the same and the hand
fastened to the shaft. Instead of fastening the nut to the diaphragm the former
may also be fastened to the hand, and the shaft must in that case be fixed to the
diaphragm, and the screw thread be constructed at the top end and be passed
through the nut of the hand.
The diaphragın may at the centre part be furnished with a recess or dish by
stamping up, and the nut may be arranged in such manner as to cover this recess,

page_text: which construction will allow the thread shaft to pass through the nut without
interfering with the diaphragm.
The enlarged movements of the diaphragm of the box are attained by forming
the box out of a set of boxes or dished diaphragms, which are attached one to the
other near the centre by means of centre rings bent or formed to the bottom and
top plates of the different boxes. The bottom plate of the undermost box is fixed
to the casing of the instrument, and supports the combined set of boxes. As each
box expends or is compressed, according to the change of the outer or inner
pressure to which the instrument is exposed, the combined movements of the several
diaphragms are transported to the upper diaphragm that influences the indicating
hand, so multiplying the effect.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said Friedrich Hermann Felix Engel in the Great Seal Patent Office
on the 20th August 1881.
FRIEDRICH HERMANN FELIX ENGEL, Civil Engineer and Patent Agent, in the
City of Hamburg, Germany. "IMPROVEMENTS IN BAROMETERS, WHICH INVENTION
IS ALSO APPLICABLE TO MANOMETERS." A communication from Johann Diedrich
Môller, of Wedel, in the Dukedom of Holstein and Kingdom of Prussia.
This Invention relates to new and very simple mechanism for transmitting the
movements of the diaphragm or diaphragms of the box of an aneroid barometer or
a manometer to the indicating hand or pointer of the instrument. The box of such
instrument may be composed of several boxes attached one to the other for the
purpose of enlarging the movements of the diaphragm.
The mode of transmitting the movements (the play) of the uppermost diaphragm
of the box to the indicating hand or pointer consists of attaching a spindle or axle
to the hand, which axle reaches down towards the box, and is furnished at the
bottom end with a screw thread cut in or formed upon it.
.
This thread passes through a nut connected with and moved by the diaphragm.
The spindle or axle is kept in position by bearings supporting both ends, or by one
top bearing and a spring.
When the diaphragm works up or down according to the change of pressure
the nut is caused to slide up or down upon the thread of the spindle, and thereby
turn the same and with it the indicating hand or pointer fastened to the said
spindle.
Instead of fastening the nut to the diaphragm the former may be fastened to
the hand, and the spindle must in that case be fixed to or connected with and
operated by the diaphragm and the screw thread be made at the top end of said
spindle and be passed through the nut of the indicating hand or pointer.
The diaphragm may at the centre part be furnished with a recess or dish (by
stamping up), and the nut may be arranged in such manner as to cover this recess,
which construction will allow the threaded spindle to pass through the nut without
interfering with the diaphragm.
The enlarged movements of the diaphragm of the box are attained by forming the
box out of a set of boxes or dished diaphragms which are attached one to the other
near the centre by means of centre rings or disc portions stamped or formed on the
bottom and top plates of the different boxes. The bottom plate of the undermost
box is fixed to the casing of the instrument and supports the combined set of
boxes. As each box expands or is compressed according to the change of the outer
or inner pressure to which the instrument is exposed, the combined movements of
the several diaphragms are transmitted to the upper diaphragm that actuates the
indicating hand or pointer, so multiplying the effect.
In order that the Invention may be clearly understood and readily carried into
effect, I have annexed hereto a Sheet of Drawings, wherein are represented con-
structions of aneroid barometers according to this Invention, the Figures 1 and 2
3 and 4 showing in each case in central transverse section and plan respectively, and
Figure 5 in central transverse section, the improved apparatus.
The instruments are made with a case or boxing a furnished with the aneroid
box formed of diaphragm compartments A, B, C, as before described, which parts
communicate internally by the ring shaped openings n¹ and m¹. In Figs. 1, 2, 3,
nd 4 the diaphragms a of the uppermost box A is formed with a recess at its
entre part that is covered by a nut 6 fastened to the diaphragm; c is the thread
ut or formed on the lower part of an upright spindle, to the upper part of which

page_text: the indicating hand or pointer d is fastened; e is a metal plate or ring attached
to the casing of the instrument, which ring is either graduated as a dial or is
covered by a dial plate fastened to it.
The central shaft carrying the hand or pointer has in the construction shown in
Figs. 1 and 2 its upper end only placed in a bearing i attached to or formed on or
in the covering glass a¹ of the instrument, and is kept in position by a spiral
springs fastened at one end to the casing and at its other end to the spindle or
shaft. This spring tends always to turn the shaft in a direction to unscrew it from
the nut; so pressing it constantly upwards into the bearing i.
Figs. 3 and 4 represent a construction in which the shaft is carried by a top
bearing as well as by a step bearing, in which case the spring s is not required. The
step bearing is supported by a bracket or armt passing through a hole in the nut b
and fastened at its other end to the casing.
The up and down movements of diaphragm a and nut bare transmitted to
the hand or pointer d by the screw c which forces the spindle or axle to turn
in either one or the other direction as the nut b slides either up or down on the
thread thereof.
In the construction shown in Fig. 5, instead of the nut 6 being fastened directly
to the top of the diaphragm a it is formed on or carried by one end of a lever p,
which is mounted on a fixed axis of motion at p₁, and at its other end is connected
to the diaphragm a in any convenient manner. By these means the movements
given by the diaphragm are enlarged and transmitted to the nut b. This con-
struction will allow of multiplying and transmitting the movements of the
diaphragm a to the hand or pointer d without altering the pitch of the screw, and
will enable more than one revolution to be given to the hand or pointer, in which
case the dial would be provided with two or more circles of divisions.
In case the nut is formed on or fastened to the hand or pointer of the instrument
instead of to the diaphragm a or to the lever p the screw spindle must be fixed to
the diaphragm a or to the transmitting lever p operated by the diaphragm.
Having now described the nature of the said Invention, and the mode in
which the same is carried into effect, I would have it understood that what
I claim is,-
In an aneroid barometer or a manometer the transmission of the movements of
the diaphragm to the indicating hand or pointer by means of a screw and nut,
either of which may be attached to or connected with the diaphragm, or may be
fixed to or form part of indicating hand or pointer, or be carried by a transmitting
lever, substantially as herein described and shown in the accompanying Sheet of
Drawings.
In witness whereof, I, the said Friedrich Hermann Felix Engel, have hereunto
set my band and seal, this Seventeenth day of August, in the year of
Land Our thousand sight hundred and eighty one.
F. H. F. ENGEL. (L.S.)