Medical syringe abstract
A medical syringe of the type in which an ampule and needle are
received in the syringe barrel and a plunger is triggered to drive
the needle from the barrel has an ampule whose body is composed
of one material, preferably glass, while the needle is sealed and
guided by a disk or plug of a different material.
Medical syringe claims
1. A medical syringe comprising:
a barrel having one end adapted to be applied against the skin
of a user for injection;
a plunger mounted on an opposite end of said barrel and spring
biased so as to be driven toward said one end upon release;
an ampule containing a liquid medicament to be injected beneath
the skin of said user, said ampule being slidably received in said
barrel and movable toward said one end thereof, said ampule including:
a cylindrical glass body;
a piston received in one end of said body proximal to said plunger
and slidable in said body,
a disk fixed in an opposite end of said body proximal to said one
end of said barrel, said piston and said disk receiving between
them an injection dose of said liquid medicament, said disk having
a central thin-walled portion adapted to be perforated and a shoulder
extending toward said one end of said barrel of a diameter less
than that of said body,
a sleeve fixed on said shoulder of said disk,
a needle support slidably received in said sleeve and having a
central boss aligned with said thin-walled portion, and
a hypodermic needle received in said boss and having a sharpened
first end juxtaposed with but spaced from said thin-walled portion
and a second end reaching toward said one end of said barrel; and
an obturator closing said one end of said barrel and adapted to
be pierced by said needle when said ampule is driven toweard said
one end of said barrel by engagement of said plunger with said piston
whereby said first end is then caused to pierce said thin-walled
portion so that further displacement of said piston in said body
by said plunger drives said medicament beneath the skin of the user.
2. The medical syringe defined in claim 1 wherein said disk is
formed with a cylindrical tubular boss aligned with said central
thin-walled portion and adapted to receive said one end of said
needle, said needle support being formed with a cylindrical recess
adapted to receive said boss.
Medical syringe description
FIELD OF THE INVENTION
My present invention relates to a medical syringe and, more particularly,
to an automatic syringe of the type which allows administration
of a medicament through the epidermis of a patient even by an unskilled
individual. More particularly, the syringe or the present invention
is of the type in which a prepackaged quantity of a medicament in
an ampule is administered through a needle subcutaneously, most
specifically by a plunger which is driven automatically to displace
the medicament from the ampule through the needle and also serves
to displace the needle from a retracted position in the instrument
into the skin of the user.
BACKGROUND OF THE INVENTION
In many cases it is important that medicaments be administratable
by an unskilled individual such as the patient himself by injection.
For this reason so-called automatic syringes have been developed
which, upon positioning against the skin, can be triggered so that
the needle is automatically driven into the skin and medicament
contained in the instrument is driven through the needle into the
Such syringes are desirable for patients suffering from allergies,
various cardiovascular disorders and certain types of diabetes which
may require immediate application of the injectable medicament so
that there is no time for the patient to reach a skilled medical
Probably the most significant of these disorders from the point
of view of immediacy, is anaphylactic shock which can require an
injection of epinephrine (adrenaline) without delay.
It is known to provide an automatic syringe which comprises a cylindrical
barrel adapted to receive an ampule containing the medicament to
be administered and which can be formed from a synthetic resin material
and provided at its end turned toward the patient, with a fitting
enabling a needle to be attached thereto so that the body of the
ampule constitutes, simultaneously the carrier of the needle and
the guide or support structure therefor.
In addition to the ampule, the barrel can be provided with a plunger
which can be spring biased so as to drive the needle into the skin
and expel the medicament from the ampule through the needle, a device
for holding the plunger against the action of the spring until release
is desired and a safety mechanism to prevent undesired discharge
of the contents of the ampule.
In practice, the system in which the ampule body of molded synthetic
resin constitutes the support for the needle and defines the wall
of the container for the medicament has proved to be disadvantageous
at least for certain medicaments such as adrenaline.
OBJECTS OF THE INVENTION
It is, therefore, the principal object of the present invention
to provide an improved syringe of the type previously described,
i.e. wherein the medicament is prepackaged in an ampule, whereby
the drawbacks of earlier devices are avoided.
A more specific object of this invention is to provide a syringe
for the purposes described, especially an automatic syringe, which
has increased versatility with respect to the medicaments which
can be used therein.
It is yet another object of my present invention to provide a syringe
capable of use by an unskilled individual which is nevertheless
reliable and effective for medicaments of all types
SUMMARY OF THE INVENTION
These objects and others which will become apparent hereinafter
are attained, in accordance with the invention, by providing the
automatic syringe of the class described with an ampule consisting
of a body of one material and a device for maintaining the position
of the needle and blocking discharge therethrough in the retracted
position, i.e. before use, of a material different from that constituting
the body of the ampule.
It is thus possible, in accordance with the invention, to form
the body of the ampule of glass, a material which is compatible
with practically all liquid medicaments, while the obturator and
positioning device can be composed of another material and can have
a significantly more limited contact with the medicament than the
glass body. This device can be composed of a synthetic resin masterial.
By providing a body of the ampule of one material and a support
and obturating device for the ampule of another material, therefore,
I am able to greatly increase the field of application of the automatic
syringe of the present invention.
According to a feature of the invention, the cylindrical glass
body of the ampule can receive a piston of synthetic resin at its
end remote from the needle, this piston being engageable by the
spring-loaded plunger in the manner described.
In one embodiment, the spring-loaded end of the body can have an
inwardly extending annular flange which engages in an outwardly
open circumferential groove in a synthetic resin disk or grommet
which can be pierced by the rear end of the needle as the needle
is engaged by a device at the end of the barrel of the syringe,
thereby enabling discharge of the medicament through the needle.
Alternatively, the cylindrical body of the ampule may extend to
the end of the syringe which is applied to the skin of the user
and the liquid medicament is retained between the piston and a sealing
disk which is axially shiftable in the body and forms a guide for
the rear end of the needle. In this case, a slug of the liquid medicament
between the piston and the disk is advanced with the needle until
the needle is captured at the end of the barrel and at this point
the rear end of the needle penetrates the disk to allow discharge
of the medicament by further advance of the piston, the disk being
When the ampule is sealed to the needle and communicates with the
interior thereof in another embodiment of the invention, the leading
end of the needle can be engaged by a seal at the extremity of the
barrel which is applied to the skin of the user. Of course, it is
also possible to seal the needle to the ampule but retain the liquid
medicament as a slug within the ampule spaced from the needle between
the piston and a disk which, by the force of the plunger, is released
after the ampule has reached the limit of its travel to permit the
liquid to be discharged through the needle.
In all cases, the end of the syringe which is applied to the skin
of the user should be closed by a membrane or web which can be pierced
by the needle, thereby insuring complete sterility of the needle
until it enters the skin.
BRIEF DESCRIPTION OF THE DRAWING
The above and other objects, features and advantages of the present
invention will become more readily apparent from the following description,
reference being made to the accompanying drawing in which:
FIG. 1 is an automatic perspective view of an automatic syringe
which can embody an ampule of the present invention showing the
safety device and firing device removed and the needle extending
in dot-dash lines;
FIG. 2 is an axial section through the syringe in its secured state;
FIG. 3 is an axial section of the syringe after firing so that
the needle has emerged but before the displacement of the liquid
FIG. 4 is another longitudinal section showing the displacement
of the liquid;
FIG. 5 is an axial section to a larger scale of the ampule of the
syringe of FIGS. 1-4;
FIGS. 6 and 7 are axial sections through a portion of the barrel
of another automatic syringe illustrating the ampule in its ready
position and in its injection position respectively;
FIGS. 8 and 9 are longitudinal sectional views illustrating a third
embodiment of the ampule of the invention showing the associated
end of the syringe with which the ampule is used, also respectively
in the storage state and the activated state;
FIGS. 10 and 11 are axial sections of a fourth embodiment of the
ampule and the associated end of the syringe, also in the storage
state and the activated state respectively; and
FIG. 12 is a longitudinal section through an ampule which represents
a modification of the embodiment shown in FIG. 5.
In FIGS. 1-4 of the drawing 1 have shown all of the elements of
a syringe according to the invention. In the remaining Figures,
I have illustrated only the ampule or the combination of the ampule
with the end of the barrel of the syringe to be applied to the skin
of the user. It will be understood, therefore, that the plunger,
trigger and safety assembly of FIGS. 1-4 is applicable to the ampules
and barrel assemblies of the other Figures as well.
As can be seen from FIGS. 1-4 the syringe basically comprises
a cylindrical housing in which the barrel consists of two parts,
namely a front part 2 and a rear part 3 interconnected by a screw
thread 4. Separation of the two barrel parts 2 and 3 at the screw
thread permits an ampule to be inserted into the barrel part 2.
The barrel part 2 is provided at its end wall with an opening 2'
closed by an elastomeric disk 5 which forms a web or membrane which
can be pierced by a needle.
The barrel part 2 thus receives an ampule 6 containing a liquid
medicament 7 and carrying at its forward end, the needle 8 in a
manner which will be described in greater detail in connection with
The other end of the ampule is closed by a sliding piston 9.
In the rest or storage position shown in FIG. 2 the ampule 6 and
the needle 8 are disposed fully within the barrel part 2 and hence
the needle 8 is not exposed to the environment and is maintained
in a sterile condition.
The rear barrel part 3 contains a plunger 10 which is biased to
the left by a compression spring 12. More particularly the plunger
10 has shoulder 10' against which one end of the spring 12 is seated,
the other end of the spring bearing against an inwardly extending
flange 3' of the barrel part 3. The spring is held in a prestressed
state by the engagement of hooks 13 of the plunger 10 over the flange
Surrounding the barrel part 3 is an axially shiftable actuating
sleeve 14 which has a cam formation 14' at its rear end, this cam
formation being engageable with the hooks as the sleeve is driven
to the left to press the hooks inwardly so they are liberated from
the flange 3' and the spring 12 can displace the plunger to the
To prevent the displacement of the sleeve 14 in this manner when
such displacement is undesired, a C-shaped clip 16 is releasably
fitted between the end of the sleeve 14 and a shoulder 3" of
the barrel part 3 around this barrel part. An additional safety
device is formed by a cap 15' which engages over the end of the
sleeve 14 and carries a pin which passes through the opening 14"
in the end of this sleeve and wedges the hooks 13 outwardly.
The tapered pin 15 is readily retracted upon removal of the cap
and the clip 16 can be removed as shown in dot-dash lines to enable
the sleeve 14 to be displaced and to release the percussion plunger
10. The cap and the clip are held together by a lanyard 16' passing
through an eye 14'" affixed to the sleeve to prevent loss of
the cap and the clip.
Once the cap and the clip have been removed, the sleeve 14 is displaced
to the left, thereby camming the hooks 13 inwardly and aligning
the spring 12 to drive the plunger 10 to the left and entrain the
ampule 6 in this direction so that the needle 8 will pierce the
disk 5 (FIG. 3). The ampule is thereby immobilized against the disk
5 and, upon piercing of the seal of the ampule in a manner which
will be described in connection with FIG. 5 the displacement of
the plunger 10 continues to force the piston 9 to the left and expel
the medicament 7 through the needle.
Referring now to FIG. 5 it can be seen that the ampule 6 comprises
a body 6' of glass, this cylindrical body having an inwardly turned
flange 6" surrounding an opening 17. The cylindrical body 6'
is freely open at its opposite end and receives the piston 9 which
is composed of a silicone elastomer.
The opening 17 is blocked by a double-lip grommet 18 or dish of
a somewhat yieldable elastomeric or synthetic resin material and
which has an H cross section defined by an annular outwardly open
groove 18' snugly receiving the flange 17.
This grommet thus has a core which fits into the opening 17 one
annular lip 19 bearing on the inner face of the flange and an annular
outer lip 20 bearing upon the outer face of the flange.
The outer lip 20 engages in and carries a cylindrical sleeve 22
which can be composed, for example of polypropylene which, in turn,
engages a needle carrier 23 of polyethylene.
The core 24 of the grommet 18 is of extremely small wall thickness
to form a web which can be perforated by the sharpened rear end
8' of the needle 8 lodged in the holder 23. Additional guidance
can be provided by a cylindrical boss 24 of the grommet which can
engage in a cylindrical recess 23' in the needle holder. It is thus
apparent that once the needle carrier 23 engages the wall formed
by disk 5 (FIG. 3) the needle 8 and the needle carrier are held
against further displacement to the left and the needle carrier,
in turn, forms a stop for the grommet 18 and thereby prevents further
displacement of the ampule 6 to the left. Since the needle is immobilized
as the grommet 18 is forced against the support 23 the point 18'
penetrates the web 24 and establishes communication with the interior
of the ampule as the plunger 10 drives the ampule and the piston
9 to the left.
In FIGS. 6 and 7 the body of the ampule is formed by a simple cylindrical
glass sleeve 25 which need not be displaced in the barrel 2 of the
syringe. This cylindrical body 25 has a length substantially greater
than that required for the slug 7 of liquid medicament which is
to be administered.
The cylindrical body 25 is closed at its rear end by a piston 9
in the manner previously described and at its front end by a disk
26 which is juxtaposed with and abuts the disk 5 previously mentioned.
The disk 26 serves to guide the needle 8 during its displacement
to the left as a comparison of FIGS. 6 and 7 will show.
The slug of liquid is defined between the piston 9 and a disk 27
which in turn is slidable within the glass body 25 and has a web
30 which is thin and can be pierced by the sharpened rear end 8'
of the needle 8. The disk 27 which forms a plunger, has a cylindrical
guide recess 28 which receives the needle carrier 29.
Consequently, when the plunger 10 is driven to the left, the assembly
27 71 9 is displaced to the left as a unit because of the incompressibility
of the liquid, thereby driving the needle 8 through the disk 5 and
at the same time causing the web 30 to be pierced by the point 8'
and establishing communication with the body of liquid. The needle
carrier 29 has a male formation 29' which engages in the recess
26' of the disk 26 and is thus immobilized while the disk 27 continues
to move to the left for the piercing action and is ultimately immobilized.
Continued displacement of the piston 9 to the left drives the liquid
through the needle into the skin.
In all cases, the syringe is positioned so that the end formed
with the disk 5 is pressed against the skin at the point at which
the injection is to occur. For convenience and simplicity the piston
9 can have the same configuration as the disk 27.
In the embodiment illustrated in FIGS. 8 and 9 the ampule 32 has
a cylindrical configuration and is closed at its rear end by a piston
9 in the manner described while its front end 33 is drawn into a
glass/metal seal with the needle 8. In this case the obturator for
the needle is formed by a disk 34 which replaces the disks 26 and
5 and has a seal 36 engaging the periphery of the needle, a cavity
35 in which the leading end of the needle is lodged, and a web 34'
which is pierced by the needle.
The ampule is thus sealed against the exterior in spite or the
fact that the liquid 7 is continuously in connection with the needle.
As the ampule is driven to the left (FIG. 9) by the plunger 10
the web 34' is pierced and the displacement is continued until the
leading end of the ampule lodges in the disk 34 whereupon continued
displacement of the plunger can drive the piston 9 to the left to
expel the liquid through the needle.
FIGS. 10 and 11 illustrate the embodiment in which the needle 8
is sealed to the end of the glass ampule 37 but has a lateral opening
43 behind a head 44 in connection with a chamber 39. The chamber
39 is defined by a constriction 38 which has a slight shoulder 42
engaging a sealing disk or plug 40 which delimits the liquid slug
7 which is also bounded by the piston 9. The plug 40 is yieldable
so that as the slug of liquid is driven to the left, it is displaced
past the shoulder 42 (see FIG. 11) in this embodiment. Moreover,
the barrel 2 of the syringe is closed by a disk 5 which is pierced
by the needle as the ampule is first forced to the left. Only upon
engagement of the end of the ampule with the disk 5 (FIG. 11) is
the force applied by the plunger 10 sufficient to displace the slug
of liquid to the left within the ampule, free the plug 40 and enable
the liquid to be displaced through the needle 8. The head 44 forms
an abutment preventing the plug 40 from blocking the opening 43.
Finally in FIG. 12 I show a modification of the ampule of FIG.
5 in which the glass ampule body is of simple cylindrical section,
i.e. is of constant cross section. One end is provided with the
piston 9 while the other end is formed with a plug 46 which has
a male portion engaging in the cylindrical body 45 and a further
cylindrical portion 48 engaging in the sleeve 49 these cylindrical
portions being separated by a peripheral shoulder 47 which abuts
both the sleeve 49 and the cylindrical body 45. The sleeve 49 surrounds
and guides the needle carrier 23 in the manner described. A thin
wall portion 50 of the plug 46 can be pierced by the point 8' of
the needle as previously described.