Improvements in Sphygmometers.
Year: 1898

page_text: Date of Application, 24th Mar., 1898
Complete Specification Left, 12th Aug., 1898-Accepted, 8th Oct., 1898
Improvements in Sphygmometers.
We, LEONARD ERSKINE HILL, of Jasmine Cottage, Frognal, Hampstead, Lecturer
on Physiology, HAROLD LESLIE BARNARD, of 36, Hamilton Road, Highbury, Fellow
of the Royal College of Surgeons, and JAMES JOSEPH HICKS, of 8, Hatton Garden,
Meteorological Instrument Maker, all in the County of London, do hereby declare
the nature of this invention to be as follows :-
We employ a glass tube provided with a flexible membrane in connection with the
lower end thereof, we supply such tube with any suitable colored water or other
fluid, we divide and figure the tube to represent millimeters of mercury and we
form at the upper end thereof an air chamber above which we construct a tap, and
above said tap we attach a flexible chamber. The instrument as above described
can be used by pressing the flexible membrane connected with the lower
end by hand against an artery at any part of the body until the maximum pulsation
of the meniscus of the fluid in the tube is obtained.
At the point on the scale where this maximal pulsation is obtained, the pressure
is read and this indicates the pressure in the artery.
Each time an observation is to be taken the tap of the instrument is first opened,
the column of liquid is set to the zero point of the scale either by pressing the
flexible membrane in connection with the top or bottom of the tube, the tap is then
closed when the instrument is ready for use.
If desired the instrument may be mounted in a holder provided with a strap or
band to fix the same around any part of the body and pressure can be applied to
the artery by screwing the lower part of the instrument through its holder.
Or the instrument may be removably mounted in one arın of a clamp the two
arms of which are capable of being pressed more or less together by a screw or
bolt and nut. In this case the wrist is placed between the two arms of the clamp
so that the lower part of the instrument rests on the radial artery and the maximal
pulsation is obtained by exerting pressure by means of the screw or nut.
The instrument may however be of U shape, or of approximately ring or scroll
form;
when of U shape one limb will be provided with the air chamber, tap and
flexible chamber at the upper end and with a scale along the length thereof whilst
the end of the other limb is connected to a flexiblo chamber which is pressed against
the radial artery as hereinbefore described.
An instrument constructed as herein described requires no correction, like the
sympiesometer, for temperature, in addition to which it can be made very compact
for use.

page_text: COMPLETE SPECIFICATION.
Improvements in Sphygmometers.
We, LEONARD ERSKINE HILL, of Jasmine Cottage, Frognal, Hampstead, Lecturer on
Physiology, HAROLD LESLIE BARNARD, of 36, Hamilton Road, Highbury, Fellow of
the Royal College of Surgeons, and JAMES JOSEPH HICKS, of 8, Hatton Garden,
Meteorological Instrument Maker, all in the County of London, 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: —
We will describe our invention in connection with the accompanying drawings in
which Fig. 1 is a front elevation and Fig. 2 a vertical section of the simplest form
of our improved sphygmometer, Fig. 3 is a front elevation and Fig. 4 is a plan of
an improved sphygmometer attached to one arm of a clamp provided with means
for pressing the arms more or less together. Fig. 5 is an end elevation of the clamp
with the lower part of the sphygmometer removably fixed therein. Fig. 6 is a
sectional plan drawn on line 6-6 of Fig. 3. Fig. 7 is a sectional plan and Fig. 8 a
front elevation of the lower part of the sphygmometer shown at Figures 3 to 6 and
its holding means, Fig. 9 is a plan of the end of the upper arm of the clamp and
Fig. 10 is a general view showing a sphygmometer of U shape connected by a tube
with a pump and with a flaccid bag capable of being bound more or less tightly
around the arm or other portion of the body.
In all the Figures like parts are indicated by similar letters of reference.
We will first describe the instrument represented at Figures 1 and 2.
a is a glass tube which is provided with a flexible membrane b in connection with
its lower end, such membrane consisting of an india rubber bag fixed to the tube a
by pressure and if desired cement between the mount c and said tube a.
We supply
such bag b and the tube a with a small quantity of any suitable colored water or
other fluid, we divide and figure the tube a as shown at a¹ to represent millimeters
of pressure by mercury and we form at the upper end thereof an air chamber a² above
which we construct a tap d and above said tap we attach a flexible membrane e by
means of a flange a³ at the upper end of the tube a over which the cup shaped
membrane e is stretched.
•
The instrument as above described can be used by pressing the flexible membrane b
by hand against an artery at any part of the body until the maximal pulsation of the
meniscus of the fluid in the tube is obtained.
At the point on the scale where this maximal puisation is obtained, the pressure is
read and this indicates the pressure in the artery.
Each time an observation is to be taken the tap of the instrument is first opened,
the column of liquid is set to the zero point of the scale either by pressing the
flexible membrane e or 6 in connection respectively with the top or bottom of the
tube a, the tap is then closed when the instrument is ready for use.
If only a small quantity of liquid is contained in the instrument the flexible mem-
brane e may be dispensed with but if such liquid should rise above the zero point
without pressure being applied thereto the flexible membrane e is needed to enable
the liquid to be depressed to the zero point.
The instrument inay as shown at Figures 3 to 8 be removably mounted in one
arm of a clamp f, the two arms f¹ f2 of which are capable of being pressed more or
less together by a screw or bolt f³ attached by pin joint f* to the arm f2 and a
nut .

page_text: In this case the mount c has a cylindrical portion c¹ to fit a cylindrical opening ƒ®
in the jaw shown at Fig. 9 and at the upper part of said cylindrical portion c¹ are
two lugs c² capable of being passed through the slot f of the jaw and then of
being turned at right angles thereto to secure the tube a to the clamps. The tube a
is removed from the clamp f by the reverse action. With this arrangement the
wrist is placed between the two arms f1f2 of the clamp so that the flexible mem-
brane b at the lower part of the instrument rests on the radial artery and the
maximal pulsation is obtained by exerting pressure by means of the screw f³ and
nut f. is a stop to limit the motion of the lugs c².
to a
The instrument may however as shown at Fig. 10 be of U shape, in which case,
one limb a is provided with the air chamber a², tap d and flexible membrane e and
with a scale and figures a¹ along the length thereof as in the instruments above
described whilst the end of the other limb a* is connected by a flexible tube
flexible chamber h which by means of a strap and buckle j can be fastened around
the arm or other part of the body. The said tube g is also connected to a pump i
whereby pressure can be applied to the interior of the flexible chamber h to cause
pressure to be applied to the radial or other artery which pressure also acts on the
liquid in the glass tube.
In this form of instrument the tube a a* is mounted on a stand k on which the
scale and figures are marked. This enables the instrument to be placed in an upright
position on a table or other support.
Instruments constructed as herein described require no correction for temperature
like the sympiesometer in addition to which they can be made very compact for use.
We would here remark that we make no claim broadly considered to the use of a
pump and flexible chamber h connected to a manometer as one arrangement of
such was shown and described in the Specification of British Letters Patent granted
to us dated May 11th 1897, No. 11719.
Having now particularly described and ascertained the nature of our said inven-
tion and in what manner the same is to be performed, we declare that what we
claim is
1. In a sphygmometer the combination of a glass tube, a scale and figures in
connection therewith, a chamber formed with a flexible membrane in connection with
the lower end, an air chamber at the upper part, a tap above such air chamber and a
small quantity of liquid in the tube, substantially as herein set forth and for the
purpose stated.
2. In a sphygmometer the combination of a glass tube, a scale and figures in
connection therewith, a chamber formed with a flexible membrane in connection with
the lower end, an air chamber at the upper part, a tap above such air chamber, a
small quantity of liquid in the tube and a flexible membrane at the upper end of the
tube a, substantially as herein set forth and for the purpose stated.
3. In sphygmometers the combination of a U shaped glass tube, a scale and
figures in connection with one leg thereof, an air chamber at the upper end of the
said leg, a tap above said air chamber, a flexible membrane above the tap, a supply
of liquid in the glass tube, a flexible tube connected to said glass tube, and a flexible
chamber and a pump connected to said flexible tube substantially as herein set forth
and for the purpose stated.
4. In sphygmometers the combination of a glass tube, a scale and figures in
connection therewith, a flexible chamber connected with the lower end of the tube,
an air chamber at the upper part, a tap above such air chamber, a supply of liquid
in the glass tube and means for applying the said flexible chamber with suitable
pressure to a part of the human body substantially as herein set forth and for the
purpose stated.
5. In sphygmometers the combination of a glass tube a scale and figures in
connection therewith, a flexible chamber connected with the lower end of the tube,
an air chamber at the upper part, a tap above such air chamber, a supply of liquid
in the glass tube, means for removably connecting said glass tube to a clamp and

page_text: means for causing the said clamp to apply the flexible chamber with suitable pressure
to a part of the human body, substantially as herein set forth and for the purpose
stated.
Dated his 10th of Aument 1000
HARRIS & MILLS,
23, Southampton Buildings, London, W.C., Agents.