Medical syringe

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.

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 subcutaneous tissues. 
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 practitioner. 
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 then immobilized. 
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.

SPECIFIC DESCRIPTION 
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 FIG. 5. 
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 3'. 
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 left. 
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.