Self-destructive non-reusable injection syringes consisting of a cylinder 1 which has a needle 2 at one end. In the cylinder a plunger head 3 with a plunger shaft 4 is placed, and in connection with the plunger head 3 or the plunger shaft 4, a release mechanism 6 is made which is released after the first use of the syringe. The release mechanism 6 consists of pieces 10, 11, 12 with at least one steering knob 13 which runs along the syringe's axial sloping path or course 14 in another body 15. The path or course 14 is at one end joined to an axially running path 16 which is open at the end 17 of the body 15. A stopper 17 for the steering knob 13 is placed at the end of the path opposite the connection with the path 16. A freely revolving joint 7, e.g., a sphere, which moves freely in a socket is connected to the plunger shaft 4 or between the plunger shaft 4 and the plunger head 3.

BACKGROUND OF THE INVENTION 
The present invention relates to self-destructive non-reusable injection 
syringes. 
The invention is first and foremost advantageous in connection with 
non-reusable syringes. Such syringes are used to a large extent by 
doctors, hospitals, diabetics and others who must have frequent 
injections. Drug users also compose a large group of users. In connection 
with the latter group of users, many problems have arisen with the reuse 
of supposed non-reusable syringes. Diseases which are spread through the 
transfer of blood, such as hepatitis B and AIDS, recently have become 
alarmingly widespread because drug users borrow each other's syringes. 
Self-destructive injection syringes which have a releasing mechanism which 
releases after the first use of the syringe are known to exist. The 
syringes proposed until now have however shown themselves to be too 
expensive to produce or have been unsafe to use because one has been able 
to manipulate the syringe in such a manner that the syringe can be used 
again. 
The purpose of the following invention is to produce a non-reusable 
self-destructive syringe which is inexpensive to produce and which is safe 
to use; in other words, the syringe is destroyed after the first use, but 
it can be aired without activating the releasing mechanism. 
SUMMARY OF THE INVENTION 
The present invention is a self-destructing injection syringe which 
consists of a cylinder with a needle in one end and a plunger head and 
plunger shaft, which has a releasing mechanism connected to the plunger 
head or the plunger shaft. The releasing mechanism releases after the 
first use of the syringe. The releasing mechanism consists of one part 
with at least one steering knob which works in coordination with one track 
or path in another part. This track or path is at an angle to the axis of 
the syringe and begins at one end of one part. This end of the path is 
open. The path runs axially to the other end of the part where there is a 
stopper attached which stops the steering knob from retreating back along 
the path. There exists also a freely moving joint-link which is connected 
to the plunger shaft or between the plunger shaft and the plunger head. 
A preferred model is one in which the steering knob or knobs are made in 
one part which is attached to the plunger shaft over the joint link, and 
the part with the tracks or paths is attached to the piston head. 
When an injection is administered with an injection syringe, the syringe 
must first be filled with the injection fluid by pulling the plunger head 
up. Next the plunger head is pushed in slightly into the syringe's 
cylinder with the needle pointing upward until all the air in the syringe 
is pushed out and the fluid begins to trickle out. The syringe is then put 
into the skin. Next the syringe must be aspired; i.e., the plunger head is 
pulled back slightly in order to ensure the correct placement of the 
needle. If this is an intravenous injection, a little blood will come into 
the syringe with the pullback of the plunger head. In order to administer 
this kind of injection with the above-mentioned non-reusable syringe, the 
preferred model of the invention is characterized by two steering knobs 
which are situated directly opposite each other at the end of two arms 
which extend axially from one part of the syringe. A cylindrical body is 
integrated with the plunger head. An angled path runs toward the plunger 
head from the part of the cylindrical body which is away from the plunger 
head. The angled path is attached to another angled path at the end 
nearest the plunger head and this second path runs in the opposite 
direction from the first path. The end of the second path which is away 
from the plunger head is attached to a further angled path which runs 
parallel to the first angled path. The third angled path is attached to a 
fourth angled path at the end nearest the plunger head. This fourth path 
runs parallel to the second path and is open along the cylindrical body's 
free edge at the end of the path nearest the plunger shaft. The paths are 
increasing in depth; the first path is not as deep as the second path, the 
second path is not as deep as the third path, and the third path is not as 
deep as the fourth path. At each connection of the paths, there is a step 
down into the next path, which ensures that the steering knob cannot be 
pulled up a path which has already been travelled.

DETAILED DESCRIPTION OF THE DRAWINGS 
The self-destructive syringe according to the invention consists of 
cylinder 1 which has one end attached to needle 2. In cylinder 1, the 
plunger head 3 can be moved along the cylinder with the help of the 
plunger shaft 4 and the plunger operating knob 5. Plunger shaft 4 is 
attached to plunger head 3 by a releasing mechanism 6, and the plunger 
shaft 4 is attached to the releasing mechanism by means of the freely 
moving joint 7. 
As is illustrated in FIG. 2, the freely moving joint 7 consists of sphere 8 
which is connected to the lower end of plunger shaft 4. Sphere 8 moves 
freely in socket 9 which is part of steering knob carrier piece 10. Piece 
10 has two projecting arms 11 and 12. At the end of each arm 11 and 12 
there are knobs 13 which point radially inward. Each knob 13 runs along 
path 14 which runs on the outside of cylindrical body 15. Path 14 begins 
at the free edge of body 15 and runs at an angle toward plunger head 3. At 
the lower end of body 15, path 14 continues into path 16. Path 16 has an 
open end 17 at the edge of body 15. An introduction path 16 at the highest 
edge of body 15 facilitates the introduction of knobs 13 into path 14. 
The syringe is assembled in the position which is shown in FIGS. 1 and 2, 
i.e., with plunger head 3 at the bottom of the syringe and knobs 13 at the 
top of path 14, so that the knob or knobs 13 lie against the stopped edge 
17 at the upper end of path 14 (illustrated in FIG. 3). The plunger head 3 
can thus be pulled up and the injection fluid is pulled into the syringe 
through the needle which is directed down into the fluid container. 
Because there is friction between the steering knobs and the path, the 
syringe can be aired or aspired without the knobs moving along the path. 
Thereafter, the syringe is put into the tissue and the plunger head is 
pushed down. The pressure upon the plunger head with the injection of the 
fluid is so great that the knobs will follow the paths and reach bottom 18 
of the path 14. The plunger head 3 now rests at the bottom of the syringe, 
as is shown in FIGS. 1 and 2, except that the knobs 13 are at the bottom 
18 of path 14. If one tries to pull up the plunger head 3 with the help of 
the plunger shaft 4 and plunger operating knob 5, the knobs 13 which are 
now located in the position shown by the dotted line will go into path 16 
and continue to go out at the open end 17. Because of the freely moving 
joint 7, the syringe cannot be manipulated in such a way that knobs 13 are 
directed into path 14 by maneuvering plunger shaft 4. It is further 
ensured that when plunger shaft 4 is pulled out, knobs 13 will be guided 
into path 16 because at the lower end of path 14, there is a sloping 
outwardly guiding edge 19. Edge 19 has its lowest point at the lowest 
point of path 14. When plunger shaft 4 is pulled out, edge 19 safely 
ensures that knobs 13 are guided into path 16. 
FIG. 5 shows the releasing mechanism in a special model where it is 
possible to air and aspire the syringe without breaking the connection 
between the plunger head and plunger shaft. 
In the same fashion as the previous example, there are two knobs 13 (of 
which only one is shown) which are attached to the elastic arms 11 which 
are attached to body 10. These knobs 13 directly face each other. 
In the cylindrical body 15, there are two equal paths which are arranged in 
a zig-zag pattern and which move in correlation with one another. The 
zig-zag pattern consists of the above-mentioned path 14 which begins at 
the free edge of body 15 and runs at an angle to plunger head 3. At the 
end which is nearest to plunger head 3, path 14 is connected to path 20 
which runs in an opposite direction to path 14. The end of path 20 which 
is nearest to the free edge (upper) of body 15 connects to path 21 which 
runs in the same direction as path 14. The end of path 21 which is nearest 
to plunger head 3 connects with the fourth path 22 which is open at the 
free edge of body 15. Path 14 of the second zig-zag pattern connects with 
path 22 near the free edge of body 15. In the connection between path 14 
and path 22, there is a block in the form of a knob or edge 23 at the end 
of the paths. 
When the syringe is assembled, the knobs 13 are directed into the upper end 
of path 22 so that they axially move over the edge 23 and into path 14. In 
this position, the plunger head 3 is now in the bottom of the syringe's 
cylinder 1. The plunger head can be pulled up when the syringe is filled. 
In order to air the syringe, plunger head 3 is pushed down with the help 
of plunger operating knob 5. Thereby, the knobs 13 slide first down along 
each path 14 to the connection point with path 20. Path 14 has decreasing 
depth from the free edge of body 15 towards the connection point with path 
20, such that path 20 has a greater depth than path 14 at the connection 
between path 14 and path 20. Step 24 is created in this way between path 
14 and path 20. In addition, path 20 becomes shallower towards path 21. 
Path 21 is deeper than path 20 at the connection between path 20 and path 
21 such that step 25 is created between path 20 and path 21. In addition, 
path 21 becomes shallower towards path 22, and step 26 is created in this 
way between path 21 and path 22. Thus, when the syringe is aired and knobs 
13 are guided down each of their paths 14, they will jump down over the 
edge of the step 24 and down onto path 20. Thereafter, when the plunger 
shaft is pulled up, knobs 13 follow path 20 and go into path 21 by jumping 
over the edge of step 25. With the knobs 13 in a connection between path 
20 and path 21, the aspiration can be performed, i.e., the plunger head 
can be pulled back up slightly. 
After the aspiration, the injection can be administered by pushing the 
plunger shaft down. In this way, knobs 13 will follow path 21 and go over 
edge 26. With the knobs 13 at the connection between path 21 and path 22, 
the injection can be performed because the knobs 13 lie at the angle 
between path 21 and path 22 which lies near plunger head 3. The plunger 
shaft is completely pressed in and the injection is administered. If one 
tries to refill the syringe by pulling up the plunger shaft, knobs 13 will 
follow path 22 and will come free from body 15. The connection between 
plunger shaft 4 and plunger head 3 is thereby broken. A new connection 
between the plunger shaft 4 and plunger head 3 cannot be made by the 
manipulation of the syringe because plunger shaft 4 was attached to 
plunger head 3 by the freely moving joint 7. The plunger shaft 4 with its 
revolving joint 7, release mechanism 6, and plunger head 3 cannot be 
pulled out of the syringe without destroying the syringe. This can be done 
in several ways, for example as is shown in FIG. 2 by the integrated top 1 
at the top of the cylinder. In syringes where the plunger shaft 4 has a 
diameter of the same dimension as the syringe's inner diameter, a top can 
be made which consists of 2 or more arms which can be inserted into the 
free space between the arms and the plunger shaft. 
The invention is not confined to the above described or to the 
illustrations shown. For example, the steering knobs may be attached to 
the plunger head, and the paths can be attached to the plunger shaft. The 
essence of the invention is the ability to perform a movement in a radial 
direction through the initial pressure on the plunger shaft, such that the 
knobs are directed towards the entrance of the axial path which has an 
open end.