Means for Measuring the Diameter of an Artery and the Pressure Required to Close it.
Year: 1895

page_text: Date of Application, 24th Jan., 1895:
Complete Specification Left, 16th S-pt., 1895-Accepted, 18th Jan.,, 1896
PROVISIONAL SPECIFICATION.
Means for Measuring the Diameter of an Artery and the Pressure
Required to Close it..
I, THOMAS PATON HAWKSLEY of 357. Oxford: Street London Surgical
Instrument Maker do hereby declare the nature of this invention to be: as
follows:-
Pressure is made upon an artery by means of a properly shaped pad, which paḍ
is 'controlled by springs.
The motion of the rod carrying the pad is communicated to an axle in the
centre of a dial which axle by means of a pointer indicates on the dial; the diameter
In use. the
of the vessel compressed or the degree of compression exerted.
instrument is held in the hand being contained in a brass box or case of cylindrical
form; and to enable greater precision in the application of the pad to the artery,
the box is provided with a foot plate or feet which are attached.to, other and
seperate springs inside the case, so that by making firm pressure upon a part
adjacent to, the, artery, the artery, pad can be precisely used as required, and I
claim protection for, a means of measuring the diameter of an artery or the pressure
equired to occlude it with greater, precision than heretofore, and; for the foot plate
to enable me to apply, the instrument.
· Dated this 23rd day of January 1895.
COMPLETE DIEUIT
Means for Measuring the Diameter of an Artery and the Pressure
Required to Close it.
I, THOMAS PATON HAWKSLEY of 357 Oxford Street London, in the County
of Middlesex, Surgical Instrument Maker, 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 :--
Pressure is made upon an artery by means of a properly shaped pad which pad
is controlled by springs.
The motion of the rod carrying the pad is communicated to an axle in the centre
of a dial, which axle by means of a pointer indicates on the dial the diameter of
the vessel compressed or the degree of compression exerted. In use the instrument
is held in the hand, being contained in a brass box or case of cylindrical form and
to enable greater precision in the application of the pad to the artery, the box is
provided with a foot plate or feet, which are attached to other and separate springs
inside the case, so that by making firm pressure upon a part adjacent to the artery,
the artery pad can be precisely used as required.
The instrument consists of a circular brass box with a glass face on one side,
through which may be seen a dial divided into grammes or ounces, millimetres or
inches, or parts of the same. By preference I use the metric system of measure-
ment. A pointer on an axis in the middle of the dial indicates the working of the
instrument

page_text: The dials of these instruments may be fixed or movable. In the movable type
of dial, Figs. 1. 2. 3. an inner circular brass box is seen which carries the mechanism
shewn in Figs. 1 and 2, and the dial in Fig. 3. The inner box has attached to it's
lower side the two circular springs A. A. and also the two guides of the foot
plate, E. E. At the upper side of the box is a socket which slides upon the
rod J. This box is kept in the position shewn in the drawing by the springs A. A.
and it's movement vertically is determined by the guides of the foot plates which
pass through the outer case and the socket sliding on J. In the middle of this
inner box is a rectangular frame K. F. the two sides of which slide freely through
holes in the cross-bar H. To the lower part F. of the frame is attached the rod of
the artery pad D. which may move freely through an aperture in both outer and inner
boxes. The object of the frame K. F. is to carry the silk thread N. and the
hair-spring L. as well as the artery pad D.
The silk thread from K. passes round the axle of the pointer O. (this axle is.
kept in position by the cock M.) and is fastened to the hair spring L, and is thereby
kept tightly stretched. A metal plate P. Fig. 2. fitting the inner box encloses the
mechanism, and has in its centre a large hole through which the axle of the pointer
projects and into which fits a metal collar S. attached to the dial plate R. This
collar fits the hole so loosely that the dial will remain in any position and at rest.
The dial is graduated as may be necessary and has a projecting stud at its zero Q.
and is shewn at the upper part in Figs. 2 and 3. The form of instrument with
fixed dial, Figs. 4. 5. 6. and 7. shews a circular brass box with a dial divided into
grammes or ounces millimetres or inches. A pointer O. on an axle in the middle
of the dial indicates the working of the instrument. The spring B. B. Figs. 4
and 5. is attached to the back of the box by means of a clamp and to the guide of
the foot plate E. at the bottom of the box and is free to move vertically. The
springs A. A. are attached to the guide of the artery pad D. by means of a short
brass plate and to the top of the box by means of two screws and are free to move
vertically. In the middle of the box is an axle kept in position by the cock M. on
which is fitted the pointer O. A silk thread N. N. attached to the guide plate of
the artery pad D. passes round this axle and is further held tight, and in position
by the hair spring L.
E. Figs. 5. 6. and 7. are three views of the footplate.
In using this instrument with a fixed dial Figs. 4. 5. and 6. to measure pressure
required to close, or the calibre of an artery; an artery tolerably exposed, as the
radial or temporal, is selected. It's exact position is determined by the finger tips
and over this spot the pad of the instrument is placed. Pressure is then gradually
made with the artery pad using the foot plates as a foundation, and sliding the box
or outer part of the instrument nearer to, or not so near to the artery until the
flow of blood has completely ceased; and the pointer shews on the dial the diameter
and pressure requisite to close it, and may be read off accordingly.
In using the instrument with a movable dial Figs. 1. 2. 3. the artery pad of the
instrument when first placed on the wrist and over an artery, slides upward or
nearer to the brass case and the pointer is turned towards the left hand carrying
with it as it revolves, the dial, by means of the projecting stud Q. This upward
movement continues until the top bar K. of the square frame K. F. touches the
stop J. when the pointer stands still. On continuing the pressure, the foot plates
slide upward, leaving the artery pad and frame at rest on the stop J.
recession of the foot plates within the box is equivalent to the artery pad being
projected or as moving downward on to the artery.
This
When this latter movement begins, the pointer at once commences to rotate
towards the right, leaving the dial at rest, and recording pressure or calibre.
Whether an artery be deeply or superficially seated, my invention allows me to
begin the measurement from a zero point, or point of no pressure. I use variously
shaped pads to make pressure on the artery, and also variously shaped foot plates
whereby pressure is made on the limb independently of the pressure made on the
artery, for the purpose of obtaining greater steadiness. I do not limit myself to

page_text: the use of, nor do I claim the details of construction described herein except as
-constituents of my said invention.
Having now particularly described and ascertained the nature of my said inven-
tion and in what manner the same is to be performed 1 declare that what I
claim is
the use of, nor do I claim the details of construction described herein except as
-constituents of my said invention.
Having now particularly described and ascertained the nature of my said inven-
tion and in what manner the same is to be performed 1 declare that what I
claim is
A means of measuring an artery, with a movable dial or scale from a constant
zero.
The pressure required to measure it with great precision.
The sliding foot plates by which to apply the instrument.
Dated this Thirteenth day of September 1895.
THOMAS PATON HAWKSLEY.