Improvements in Syringes for use in Subcutaneous or other Injections.
Year: 1897

page_text: PROVISIONAL SPECIFICATION.
Improvements in Syringes for use in Subcutaneous or other
Injections.
I, HENRY SOLOMON WELLCOME (trading as Burroughs Wellcome & Company),
of Snow Hill Buildings, Holborn, London, in the County of London, Manufac-
turing Chemist, do hereby declare the nature of this invention to be as follows;
In hypodermic syringes at present used the plungers do not thoroughly eject
the contents from the barrel of the syringe owing to the fact that the piston rods
do not extend to the end of the nozzles but only to the outlet of the barrel. The
disadvantages of this are that a small quantity of the solution remains in the
nozzle of the syringe which is detrimental to the instrument if the solution be of
a corrosive character. Further as it is difficult to measure the quantity of solu-
tion retained in the nozzle accurate allowance cannot be easily made when filling
the barrel of the syringe with sclution for the purpose of injection.
Now the piston of my syringe is provided with an extension which by pressing
the plunger into its place is caused to fill the cavity in the nozzle of the syringe
thereby effecting a complete ejection of the contents of the barrel. The pro-
jections upon the piston rod between which the packing is placed are made in
conical or other suitable shape for the purpose of facilitating the expansion of
the packing.
My improved piston may, be made of metal, vulcanite or other suitable
substance.
Dated this 24th day of September 1897.
Improvements in Syringes for use in Subcutaneous or other
Injections.
I, HENRY SOLOMON WELLCOME (trading as Burroughs Wellcome & Company),
of Snow Hill Buildings, Holborn Viaduct, London, E.C., in the County of London,
Manufacturing Chemist, 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 objects in view in the improvements hereinafter recited are the following:
One of the objects is to provide in hypodermic or other surgical syringes means
for more thoroughly expelling the contents of the barrel than is generally possible
in syringes of this type.

page_text: The attainment of this object renders two important advantages one of which
is, the avoidance of the detrimental effect which is frequently caused by the inad-
vertent retention in such instruments of corrosive solutions, and the other is the
facility to more exactly administer medicinal preparations which is particularly
important where such contain potent poisons.
Another object is to provide in hypodermic or other surgical syringes a more
reliable means of expanding the packing upon the piston.
The improvements in syringes hereinafter more particularly described are shown
in the accompanying drawings of which
Fig. 1 is a representation of a piston rod provided with an elongation A and
with a conical flange or presser B.
Fig. 2 is a representation of a tubular presser which is also provided with a
conical flange C. This tubular presser receives the piston rod as shown in Fig. 3.
Fig. 3 is a sectional drawing of a complete syringe showing the elongation of
the piston rod within the diminishing bore of the syringe nozzle and the flanges
upon the piston rod and tubular presser engaging with the packing upon
the piston.
Now the means I adopt for the thorough ejectment of solutions from the barrel
of my improved syringe is the elongation of the piston rod A shown in Fig. 1: The
essential feature in the construction of this elongation of the piston rod is a
tapering or gradually diminishing circumference from its base downwards to the
end. The nozzle of the syringe contains a bore for the reception of the elonga-
tion A and is turned or moulded with a gradually decreasing diameter from
its point of juncture with the casing of the barrel of the syringe to its outer ter-
mination as shown in the sectional drawing Fig. 3. The decrease in the circum-
ference of the elongation of piston rod and the decrease in the diameter of the
bore of the syringe nozzle are relatively the same. The nozzle of the syringe is
screwed into the casing of the barrel or attached to the body of the syringe in
any other suitable manner.
I manufacture my improved piston of metal, vulcanite or other suitable sub-
stance by turning or moulding or in any other suitable manner.
It will be easily seen that by constructing the piston rod and nozzle of a
syringe in this manner the contents of the barrel are most thoroughly ejected
the elongation of the piston rod completely filling up the bore in the nozzle
of the syringe when the piston is pushed to its extremity. It is also apparent
that an elongation of the piston rod would be worthless if manufactured of the
same circumference throughout as in that event it would only impede the expul-
sion of the solution or entirely block the passage in the nozzle before the contents
of the barrel were fully discharged.
By the construction of my piston rod and nozzle in this manner I attain one
of the objects of this invention hereinbefore recited.
In hypodermic and other surgical syringes at present used the pressers between
which the packing of the piston is placed are generally flat discs but it will be
seen in Figures 1 and 2 that one of my improvements consists in the manufacture
of pressers B and C which take a slightly conical shape. Fig. 2 is à presser of
tubular form which, receives the piston rod the latter entering into the tubular
presser at C so that the pressers B and C are brought into a position immediately
facing each other. Between these pressers the packing is placed and the pres-
sure upon the packing is regulated by a regulating nut beneath the knob at end of
piston rod in the usual manner. In Fig. 3 the pressers B and C are shown in
contact with the packing. When the regulation nut of the piston rod is turned
for the purpose of expanding the packing, the latter is thrust in an outward direc-
tion so as to more tightly fit into the barrel. It will be seen that the advan-
tage of the conical shape of these pressers is very definite compared with the use
of pressers which have flat surfaces. When pressers with flat surfaces are
employed the effect of tightening them together is a deterioration of the packing
which becomes compressed and hardened but not necessarily expanded, whereas

page_text: in my syringe the pressure upon the packing may be regulated without fear
of detrimental effect.
Having now particularly described and ascertained the nature of my inven-
tion and in what manner the same is to be performed I declare that what I
claim is-
(1) An improvement in the construction of syringes for use in subcutaneous
or other surgical injections consisting of a tapering elongation of the piston rod
substantially as and for the purpose described.
(2) A gradually diminishing bore in an adjustable nozzle for the reception of
the tapering elongation of the piston rod substantially as and for the purpose
described.
(3) An improvement in the construction of syringes for use in subcutaneous
or other surgical injections consisting of the construction of a piston composed of
a piston rod and tubular presser each of which are provided with conical flanges
for the purpose of facilitating the expansion of the packing, said flanges taking
the form of truncated cones having their bases farthest from the packing of the
piston substantially as and for the purpose described and as illustrated in the
drawings forming part of this specification.
Dated this Tourth dow of Nov 1900