Injection syringes of this type are known in practice. After the liquid which is present in the liquid container of the injection syringe has been ejected, by way of example a coupling is effected between the piston head of the piston and the needle mount of the needle, in order to allow the needle to be retracted. As a result of the piston then being moved backwards again, the needle can be pulled into the liquid container of the injection syringe, so that it is possible to prevent the risk of injury on the needle. Moreover, this ensures that the injection syringe is not reused.

One particular drawback of known injection syringes is that special features have to be provided on the inner wall of the liquid container in order on the one hand to enable the needle mount with needle to be retracted into the liquid container after it has been used, while on the other hand ensuring that the needle mount does not inadvertently retract into the liquid container during injection.

Consideration may be given in this context, by way of example, to recesses, projections and the like in the liquid container. These special features on the inner wall of the liquid container make the production process for the liquid container-and therefore for the injection syringe as a whole-expensive. One example of an injection syringe having special features of this type on the inner wall of the liquid container is described in European patent application EP 0 795 338.

Moreover, it has been found that, even if liquid containers having special features of this type are produced with the utmost care, there is a relatively high scrap rate, i. e. by no means all the liquid containers produced are suitable for use. It will be clear that this is highly undesirable.

A further drawback of the known injection syringe is that the needle, when it is being fitted to the outlet opening of the liquid container, is difficult to position, i. e. in the known injection

syringe the coupling means which may be required for retraction of the needle have to be fitted very accurately through the outlet opening of the liquid container. If this is not done carefully, as is often the case in everyday use, this may mean that the needle is not stably secured to the outlet opening of the liquid container and/or that the coupling means may be damaged slightly, with the result that it is impossible to ensure reliable retraction of the needle after the injection syringe has been used.

It is an object of the present invention to solve the above and further drawbacks.

A further object of the present invention is to provide a leak-free injection syringe with a retractable needle which is simple to produce (in particular its liquid container) and is also simple to use.

Another object of the present invention is to provide a leak-free injection syringe which can be produced using the minimum possible number of components and at the lowest possible cost.

One or more of these objects are achieved by the present invention by means of an injection syringe assembly with retractable needle, at least comprising: - a liquid container with a substantially annular outer edge which defines an outlet opening, the outer edge forming part of a narrowed section of the liquid container; - a piston which can be displaced within the said liquid container and has a piston head, to which a piston rod is or can be secured; - a needle with needle mount which is or can be secured in or on the outlet opening of the liquid container; and - blocking means which are designed to block the needle mount in the outlet opening, which blocking means can be unblocked; the blocking means, during blocking of the needle mount, interacting with the outer edge of the liquid container, and the blocking means forming part of the needle mount.

The injection syringe with retractable needle according to the

present invention is simple and inexpensive to produce, on account of its simple structure and the small number of components.

One particular advantage of the present invention is that in principle a very simple liquid container can be used for the injection syringe, yet after the liquid container has been emptied, it is possible to reliably retract the needle into the liquid container. The needle mount according to the present invention can therefore be used for simple liquid containers which are provided, for example, with a standard cone.

According to the present invention, the liquid container is preferably a standard liquid container, i. e. a liquid container which is of substantially smooth design on its inner side, and therefore does not have any special recesses or projections for securing of the needle mount as described, for example, in the abovementioned European patent application EP 0 795 338. Furthermore, the liquid container will generally be provided with a standard cone, i. e. a narrowed section on which the needle with needle mount can be secured.

A further advantage of the injection syringe according to the invention is that the needle mount with needle is very easy to fit in or on the outlet opening of the liquid container of the injection syringe, and the risk of damage to the coupling means of the needle mount and the piston head, which can occur in the known injection syringes, is substantially minimized. It has been found that the needle mount with needle can also be positioned in or on the outlet opening automatically, which has hitherto been problematic.

In the injection syringe according to the invention, the outer edge of the liquid container forms part of a narrowed section of the liquid container. This narrowed section is generally a standard cone to which the needle mount with needle can be secured. If desired, by way of example, a Luer lock or any other known closure can be used to secure the needle mount.

The outer edge of the narrowed section of the liquid container defines the outlet opening of the liquid container. The outer edge is

therefore an external,"outer"edge positioned on the outside of the liquid container. As can be seen, for example, from Fig. 1, which is discussed in detail below, the outer edge 4 is positioned at that end of the narrowed section 11 of the liquid container 3 which is remote from the piston 6. It is preferable for the top of the outer edge 4 as shown in Fig. 1 to be of substantially planar design, so that the blocking means 12 can easily be supported thereon, at least in their blocking state.

In general, the injection syringe according to the present invention is very simple and safe to use, without any complicated actions having to be carried out.

The person skilled in the art will understand that the needle with needle mount can be secured in or on the outlet opening in various ways, provided only that safe and stable securing is provided.

The injection syringe according to the present invention may furthermore be designed in various ways in order to enable the needle, after the liquid container has been emptied, to be moved into the liquid container.

Furthermore, the blocking means according to the invention can be designed in various ways so as to block the needle mount in the outlet opening. By way of example, the blocking means can be unblocked as a result of the needle mount being coupled to the piston head. The presence of the blocking means prevents the needle, when it is secured to the outlet opening of the liquid container, from inadvertently moving into the liquid container during use (for example during injection). It has been found that the injection syringe according to the present invention, on account of the blocking means used, can withstand relatively high forces without the needle inadvertently moving into the liquid container. Consequently, the needle mount with needle can only enter the liquid container once the blocking means have been unblocked. The person skilled in the art will understand that the blocking means can be designed in various ways for this purpose, provided only that unblocking can be provided once the liquid container has been emptied. The blocking means form part of the needle mount. This simplifies assembly of the injection

syringe.

Since the blocking means, to effect the blocking action, interact with the outer edge of the liquid container which defines the outlet opening, the inner wall of the liquid container need not be provided with special recesses, projections and the like, which offers particular advantages in terms of production engineering.

When the injection syringe according to the invention is in use, the blocking means are unblocked, for example by coupling between the piston head and the needle mount of the needle (for example obtained as a result of the piston being moved in the direction of the outlet opening), after the liquid container has been emptied. On account of the fact that the needle mount of the needle is as a result released from the outlet opening of the liquid container, the needle mount with needle can then be introduced into the liquid container.

To allow reliable retraction of the needle into the liquid container, it is preferable for the injection syringe to comprise coupling means which are designed to be capable of coupling, in order that, after the piston head has been moved fully into the liquid container in order for liquid which is present in the liquid container to be substantially completely discharged via the outlet opening, the injection needle can be pulled into the liquid container after the piston head has been coupled to the needle mount of the needle.

In the event of the possible coupling between the piston head and the needle mount of the needle, it is preferable to form an "unmistakable"coupling, i. e. for this coupling not to be effected by means of, for example, clamping or friction. This is because coupling based on friction may be inadequate for the needle mount with needle to be pulled into the liquid container after the liquid container has been emptied.

According to a particularly preferred embodiment of the injection syringe according to the present invention, the blocking means comprise one or more (for example pivoting or resilient) ribs which, during the blocking of the needle mount in the outlet opening, can engage on the outer edge of the liquid container. It is preferable

for at least one of the ribs to comprise a projection which, during blocking, is positioned substantially downstream of the outer edge (in this case outside the liquid container). As a result, to block the needle mount in the outlet opening and to enable the needle to be retracted into the liquid container, it is nevertheless possible to use a standard liquid container which has a substantially smooth inner wall. The liquid container can therefore do without recesses and projections on its inner wall for the purpose of securing and blocking the needle mount.

A further result of this is that, at the same time as the piston head is being coupled to the needle mount, it is also possible for the blocking means to be unblocked, so that the needle mount with needle can be retracted.

To this end, the blocking means are advantageously designed in such a manner that the blocking means can be unblocked by the piston being moved away from the outlet opening after the needle mount has been coupled to the piston head. This provides very simple unblocking of the blocking means.

According to a particularly elegant embodiment of the injection syringe according to the present invention, the two ribs, on which one or more projections may be placed, are connected to one another at a connection point on that side of the needle mount which faces the piston head. In this case, at least one of the ribs preferably has a curvature which is substantially transverse with respect to the direction of the longitudinal axis of the liquid container.

The result of this is that, when the needle has been retracted into the liquid container, the needle adopts a position at an angle with respect to the longitudinal axis of the liquid container. If the piston head is then moved back in the direction of the outlet opening of the liquid container, the needle will remain in the liquid container. It is preferable for the curvature of the at least one rib in this case to have a radius of curvature which is such that the needle, after it has been retracted into the liquid container, is inclined towards a reinforced part of the liquid container, thereby substantially preventing the needle from penetrating through the

liquid container. The person skilled in the art will know how to select an appropriate radius of curvature as a function of the dimensioning and design of the injection syringe.

As an alternative to one of the ribs being provided with a curvature, it is also possible-in order to obtain the same effect-for the one or more ribs to be provided with all other suitable means which allow the needle, in the retracted state in the liquid container, to be positioned at an angle with respect to the longitudinal axis of the liquid container. In this context, consideration may be given, for example, to suitable positioning or dimensioning of the ribs with respect to one another.

The ribs may be of any suitable form, and are generally designed in such a manner that they form a connection between, on the one hand, that part of the needle mount in which the needle is secured and, on the other hand, the connection point which is located at a position of the needle mount facing towards the piston head.

Furthermore, the person skilled in the art will understand that the connection point of the ribs may be designed in various ways, provided only that the intended effect is provided. Of course, the connection point may also be a connection zone.

Furthermore, it is preferable if the ribs of the needle mount can be moved closer together when the needle is being retracted into the liquid container as a result of the piston head being coupled to the needle mount. As a result, as soon as the piston head has been coupled to the needle mount, simple yet effective unblocking of the blocking means is provided, in order to enable the needle to be retracted into the liquid container.

The person skilled in the art will readily understand that the ribs can be designed in various ways for this purpose, provided only that it is possible for the ribs to be moved closer together as the needle is retracted into the liquid container. By way of example, the ribs may for this purpose comprise a hinge or curvature. It is preferable for the ribs and the connection point to be designed in such a manner that together they are substantially oval or elliptical in form.

Furthermore, it is preferable for the ribs to be of resilient design.

Furthermore, according to the present invention it is preferable for the needle mount, on its side facing the piston head, to comprise a sleeve-like element in which there is a through-opening (for liquid to pass through). In this case, it is advantageous for the sleeve- like element, in the blocked state of the needle mount, to be positioned in the narrowed section of the liquid container.

According to a further, particularly preferred embodiment of the injection syringe according to the present invention, the injection syringe also comprises a cylindrical element which is positioned slideably in the narrowed section of the liquid container and which can unblock the blocking means by being pressed on with the aid of the piston head.

This allows reliable unblocking of the blocking means to be provided in a particularly simple way.

It is particularly preferable for the cylindrical element to comprise a seal for the sleeve-like element. As will be explained below in Fig. 5 and 6, the result of this is that no special coupling means are required to enable the needle to be retracted into the liquid container. In this case too, it is possible for the liquid container used to be a standard liquid container, i. e. a liquid container which is not provided with recesses, projections or the like on its inner side. It will be clear that this offers particular advantages from a production engineering point of view.

Furthermore, according to the present invention it is preferable for the blocking means to be designed in such a manner that, while they are being unblocked by the piston head being coupled to the needle mount, they can be at least partially displaced in a direction which is substantially transverse with respect to the longitudinal axis of the liquid container.

The person skilled in the art will readily understand that the needle mount-of which the blocking means generally and preferably form part-can be designed in various ways for this purpose.

In this context, in a particularly expedient form, the blocking means are connected to the needle mount, and the blocking means comprise a substantially annular element, which annular element, in a first, blocking state, can rest on the outer edge of the liquid container and, in a second, unblocked state, can move into the liquid container. The person skilled in the art will readily understand that the needle mount and blocking means can be connected in numerous different ways for this purpose, for example using a flexible material.

In this context, it is particularly expedient for the annular elements to be connected to the needle mount via at least two second ribs, with the annular element being displaced slightly with respect to the needle mount in the first, blocking state.

Furthermore, according to the present invention it is preferable for the injection syringe to comprise a spring member for moving the needle mount into the liquid container after the blocking means have been unblocked.

This furthermore ensures that, after the blocking means have been unblocked, the needle mount with needle can enter the liquid container.

One particular advantage of using the spring member is that it may be possible to do without a coupling between the piston head and needle mount in order to enable the needle mount with needle to be introduced into the liquid container.

It is advantageous for the spring member to be positioned downstream of the outer edge of the liquid container and for the spring member to form part of the needle mount. As a result, once again there is no need for separate features to be provided on the inner side of the liquid container, which offers benefits in terms of production engineering.

Furthermore, it is advantageous if the spring member can be blocked, preferably by a spring-member blocking means. This prevents the

unintentional application of pressure to the needle mount by the spring member. In this context, it is also possible for the spring- member blocking means to function as a"prestressing means" ; if the spring member is to be fitted in the injection syringe by the user himself, the spring member remains in the desired position during assembly for as long as the spring-member blocking means has not been deactivated.

According to a particularly simple and expedient embodiment, the spring-member blocking means can in this case interact with a protective cap in order to block the spring member. Also, the spring- member blocking means preferably forms part of a securing element which can secure the needle mount on a liquid container from the outside in a liquid-tight manner.

The present invention also relates to a needle mount and a securing element which are clearly intended for the injection syringe according to the invention.

The present invention will be explained in more detail below on the basis of the appended, non-limiting drawing, in which: Figure 1 shows a diagrammatic cross section through a first embodiment of an injection syringe according to the invention ; - Figure 2 shows a diagrammatic, perspective view of the needle mount of the injection syringe shown in Fig. 1; - Figures 3 and 4 show alternative embodiments for the needle mount in the injection syringe shown in Fig. 1; - Figure 5 shows a diagrammatic cross section through an alternative embodiment of the injection syringe according to the invention, in which the injection syringe is provided with a cylindrical element; - Figure 6 shows the injection syringe shown in Fig. 5, in which the liquid container has been emptied; - Figure 7 shows a diagrammatic cross section through a further embodiment of the injection syringe according to the invention; - Figure 8 shows a perspective view of the needle mount of the injection syringe shown in Fig. 7; - Figure 9 shows a diagrammatic cross section through another alternative embodiment of the injection syringe according to

the invention, in which the injection syringe is provided with a spring member; Figure 10 shows the injection syringe shown in Fig. 9, in which the liquid container has been emptied and the coupling means have been unblocked; Figure 11 shows a diagrammatic perspective/cross-sectional view of the injection syringe shown in Fig. 9; and Figure 12 shows a diagrammatic cross section through a further embodiment of the injection syringe according to the invention, in which the injection syringe is provided with a spring-member blocking means.

Identical reference numerals denote similar components. Some figures are shown as partial views, for the sake of clarity.

Figure 1 shows a diagrammatic cross section through a first embodiment of an injection syringe 1 with retractable needle 2 in accordance with the present invention. The injection syringe 1 comprises a liquid container 3 with a narrowed section 11 and with a substantially annular outer edge 4 which defines an outlet opening 5.

A displaceable piston 6 with a piston head 7, to which a piston rod 8 is secured, is present inside the liquid container 3. The needle 2 with needle mount 9 is secured in the outlet opening 5 of the liquid container 3. The outer edge 4 is positioned at that end of the narrowed section 11 of the liquid container 3 which is remote from the piston 6. The top of the outer edge 4 is of substantially planar design, as shown in Fig. 1.

The injection syringe 1 comprises a securing element or cap 21 which secures the needle mount 9 to the liquid container 3 from the outside in a liquid-tight manner. In this context, use may be made, for example, of a Luer lock which is known per se or of some other coupling means which will not be explained in more detail in the present context.

The needle mount 9 of the needle 2 and the piston head 7 comprise coupling means which are designed to be capable of unmistakable coupling, in order that, after the piston head 7 has been moved fully into the liquid container 3 in order for liquid 10 that is present in

the liquid container 3 to be discharged via the outlet opening 5, the needle 2, after the piston head 7 has been coupled to the needle mount 9 of the needle 2, can be pulled into the liquid container 3.

As a result, the user, after the injection syringe 1 has been used, can no longer easily be injured by the needle 2. This also prevents the injection syringe 1 from being reused. The term"unmistakable" coupling to one another is to be understood as meaning that a reliable coupling is created, i. e. the coupling is not based on friction or a clamping action. The person skilled in the art will understand that the piston head 7 and the needle mount 9 can be designed in a wide range of different ways in order to allow them to be coupled. For example (cf. Fig. 7, for example), the piston head 7 may be provided with a pin-like body which can engage in the needle mount 9.

The outlet opening 5 of the liquid container 3 comprises a narrowed section 11 (generally a standard cone). The narrowed section 11 forms part of the liquid container 3 and is fixedly connected to it, thereby contributing to improved sealing of the injection syringe 1.

The needle mount 9 with needle 2 is blocked in the outlet opening 5 of the liquid container 3 by means of blocking means 12. In the embodiment shown in Fig. 1, the blocking means 12 comprise two pivoting ribs 15 which can interact with the outer edge 4 of the liquid container 3 during blocking. The blocking means 12 are designed to block the needle mount 9 in the outlet opening 5 during injection, and in the embodiment shown can be unblocked by the piston head 7 being coupled to that side 13 of the needle mount 9 of the injection syringe 1 which faces the piston head 7.

The presence of the blocking means 12 allows a relatively great force to be exerted on the needle 2 when a patient is being injected without any risk of the needle mount 9 in the process shooting out of the outlet opening 5 into the liquid container 3. Indeed, when a force of this nature is applied during injection, the blocking means 12 will be seated even more securely.

If desired, the ribs 15 of the blocking means 12 may comprise a projection (14 ; cf. Figs. 3,4 and 9) which is positioned downstream

of the outer edge 4, i. e. on top of the outer edge 4 and outside the liquid container 3, during blocking of the needle mount 9 in the outlet opening 5.

In the embodiment shown, the two ribs 15 are connected to one another at a connection point or zone 16 on the side 13 facing the piston head 7. The ribs (or bridge elements) 15 are in this case at one end secured to that part of the needle mount 9 in which the needle 2 is secured, and at the other end meet in the connection point or zone 16, which forms part of a sleeve-like element 17. In the blocked state of the needle mount 9 in the outlet opening 5 shown, the sleeve-like element 17 is positioned in the narrowed section 11 of the liquid container 3.

It is easy to fit the needle mount 9 with the needle 2 on the narrowed section 11, and the risk of damage to the ribs 15 by the needle mount 8 being minimized.

The person skilled in the art will readily understand that it is also possible to use three or more ribs instead of two ribs 15. Not all the ribs need necessarily include a projection 14, although according to the present invention it is preferable for them to do so.

Furthermore, the injection syringe also has an additional annular seal 20 which is intended to improve the leaktightness of the injection syringe 1. In Fig. 1, the seal 20 forms part of the securing element 21.

For the sake of clarity, Figure 2 shows a diagrammatic, perspective view of the needle mount 9 with needle 2 of the injection syringe 1 shown in Fig. 1. That side 13 of the needle mount 9 which faces the piston head is provided with grooves, thereby ensuring stable coupling to the piston head 7.

When the injection syringe 1 shown in Fig. 1 is in use, the injection syringe 1 will be emptied as a result of the liquid 10 that is present in the liquid container 3 being forced through the needle 2 as a result of the piston 6 being moved towards the outlet opening 5.

In a substantially empty state of the injection syringe 1, i. e. when

the piston head 6 has been pressed onto the outlet opening 5, the piston head 7 of the piston 6 will be coupled to that side 13 of the needle mount 9 which faces the piston head 7. In the process, the piston head 7 and the needle mount 9 will interact and provide unmistakable coupling.

If the piston 6 is then pulled back away from the outlet opening 5 with the aid of the piston rod 8, the ribs 15 of the needle mount 9 will be moved closer together. As a result, the blocking means 12 are unblocked and the needle mount 9 with needle 2 can be pulled into the liquid container 3, which it cannot readily be moved out of again.

This prevents the possibility of the needle 2 being reused. This also minimizes the risk of injury on the needle 2, as well as the risk of transmission of infectious diseases.

It is preferable for one of the ribs 15 to have a curvature with a radius of curvature which is such that the needle 1, after it has been retracted into the liquid container 3, is inclined towards a reinforced part (the narrowed section 11 in Fig. 1) of the liquid container 3, which substantially prevents the needle 2 from penetrating through the liquid container 3.

Figs. 3 and 4 show alternative embodiments of the needle mount 9 in the injection syringe 1 according to the invention. When the piston head 7 is coupled to the needle mount 9 and then the piston 6 is retracted, the projection 14 will yield inwards and then release the needle mount 9, with the result that the needle mount 9 can be retracted into the liquid container 3.

In Figure 4, the needle mount 9 is of slightly shorter design, so that it can more easily be centred on the liquid container 3 when it is being fitted to it. In order nevertheless to allow coupling to be produced, the piston head 7 is for this purpose provided with an elevated section 27 (cf. the pin-like body 25 shown. in Fig. 7).

Figs. 5 and 6 show a diagrammatic cross section through an alternative embodiment of the injection syringe 1 according to the invention, the injection syringe 1 being provided with a cylindrical element 18. The cylindrical element 18 helps to unblock the blocking

means 12, with the result that the blocking means 12 are unblocked as soon as the piston head 7 of the piston 6 pushes on the cylindrical element 18, without coupling being effected between the needle mount 9 and the piston head 7.

That side 13 of the cylindrical element 18 which faces the piston head 7 is provided with a closure element 28.

If, after the liquid container 3 has been emptied (cf. Fig. 6), the piston head 7 is retracted back into the liquid container 3, the action of vacuum (partially caused by the closure element 28) causes the unblocked needle mount 9 to be moved into the liquid container 3.

Therefore, there is no need for the piston head to be provided with a recess or the like, as is provided, for example, in the embodiment shown in Fig. 1; therefore, there is also no coupling between the needle mount 9 and piston head 7.

In the embodiment shown in Figs. 5 and 6, unlike in the embodiment shown in Fig. 1, the annular seal 20 forms part of the needle mount 9.

Figure 7 shows a diagrammatic cross section through a further embodiment of the injection syringe 1 according to the invention.

In the embodiment shown in Fig. 7, the blocking means 12 are designed in such a manner that, while they are being unblocked as a result of the piston head 7 being coupled to the needle mount 9, they can be at least partially displaced in a direction which is substantially transverse with respect to the longitudinal axis of the liquid container 3. For this purpose, the blocking means 12 are connected to the needle mount 9 and comprise a substantially annular element 22, which annular element, in a first, blocking state (as shown in Fig. 7), can rest against the outer edge 4 of the liquid container 3 and, in a second, unblocked state (not shown), can move into the liquid container 3. The annular element 22 is in this case connected to the needle mount 9 via at least two second ribs 23.

The piston head 7 of the piston 6 in this case comprises a pin-like

body 25 which can engage in the needle mount 9, all this in such a manner that the annular element 22 can as a result be displaced (in this case centred), so that the needle mount 9 with needle 2 can be retracted into the liquid container 3 via the narrowed section 11.

The person skilled in the art will readily understand that in the case shown in Fig. 7, it is also possible to use a single piece of flexible material as an alternative to the two second ribs 23, provided only that the intended effect can be achieved.

For the sake of clarity, Figure 8 shows a perspective view of the needle mount 9 (shown without needle 2) of the injection syringe 1 shown in Fig. 7.

The injection syringe 1 shown in Fig. 7 is preferably also provided with a spring member 24 as explained in Fig. 9.

Figs. 9 and 10 show a diagrammatic cross section through another alternative embodiment of the injection syringe 1 according to the invention, the injection syringe 1 being provided with a spring member 24 for moving the needle mount 9 into the liquid container 3 after the blocking means 12 have been unblocked.

In the embodiment shown in Fig. 9, the spring member 24 is positioned downstream of the outer edge 4 of the liquid container 3, i. e. the spring member 24 is located outside the liquid container 3. Although the spring member 24 may also be positioned inside the liquid container 3, for production engineering reasons, according to the present invention it is preferable for the spring member 24-in the blocked state of the needle mount 9-to be located outside the liquid container 3. Furthermore, it is preferable for the spring member 24 to form part of the needle mount 9.

One particular advantage of the presence of the spring member 24 is that as a result it is not necessarily a requirement to use coupling means (for coupling the needle mount 9 to the piston head 7-cf. for example Fig. 1) in order to enable the needle mount 9 with needle to be moved into the liquid container 3.

In Fig. 10, the piston head 7 has been moved as far as possible into the liquid container 3, with the result that the blocking means 12 are unblocked (with the aid of the cylindrical element 18). When the piston head 7 is then moved back again, the needle mount 9 will follow the piston head 7 as a result of the action of the spring member 24. In this context, it is particularly advantageous that the needle mount 9 does not immediately shoot inwards, but rather that the speed of the inwards movement of the needle mount 9 can be selected by the user himself.

For the sake of clarity, Figure 11 shows a diagrammatic perspective/cross-sectional view of the injection syringe 1 shown in Fig. 9.

Finally, Fig. 12 shows a partial cross-sectional view through an injection syringe 1 according to the invention in which the injection syringe is provided with a blocking means 25 for the spring member 24. In the embodiment shown, the spring-member blocking means 25 forms part of the securing element 21. The spring-member blocking means 25 is unblocked in use as soon as the protective cap 26 (which protects the needle 2 from damage) is removed. Since the blocking means are not yet unblocked, the spring member 24 will not yet be able to push the needle mount 9 back into the liquid container 3; this only occurs after the needle mount 9 has been released from the outlet opening 5 as a result of the unblocking of the blocking means 12 (cf. also the explanation given above) and the piston 6 is moved away from the outlet opening 5.

The person skilled in the art will readily understand that the invention can be varied in numerous ways without departing from the scope of the invention. For example, the injection syringe 1 may be provided with means for preventing the needle mount 9 from being able to rotate during injection.