EP1684830A1

EP1684830A1 - Device for the administration of an injectable product

Info

Publication number: EP1684830A1
Application number: EP04789818A
Authority: EP
Inventors: Edgar Hommann
Original assignee: Tecpharma Licensing AG
Current assignee: Tecpharma Licensing AG
Priority date: 2003-11-05
Filing date: 2004-10-28
Publication date: 2006-08-02
Also published as: CN1878587A; WO2005044344A1; JP2007509657A; US20060264830A1; AU2004286732A1; AU2004286732B2; DE10351594A1; US8591465B2

Abstract

Disclosed is a device for administering an injectable product, comprising a housing (1, 10), a product container (2) that is accommodated by said housing (1, 10), a piston rod (16) which acts upon a piston (3) in a direction of propulsion (V), and a spring (15) that acts upon the piston rod (16) in the direction of propulsion (V). The product container (2) is movably mounted and is provided with a piston (3) which is accommodated so as to be movable in a direction of propulsion (V) in order to dispense product. The piston rod (16) is removably retained in a holding engagement counter to the force of the spring (15) in a holding position. The spring protrudes into the container (2) in the holding position.

Description

Device for administering an injectable product

The invention relates to a device for the administration of an injectable product. The device can in particular be an injection device, preferably an auto-injector.

Injection devices, as the invention also relates to them, are known for example from DE 198 22 031 B and US Pat. No. 4,031,893. Both documents describe auto-injectors. In the auto-injector of DE 198 22 031 AI, a mechanical sequence control ensures that after the triggering of the device, the injection cannula is pierced through the skin to the desired depth in a first phase and the product to be injected is only poured out in a subsequent second phase and is administered by it. The injection device of US Pat. No. 4,031,893 does not have such a sequence control. Rather, a drive device pushes both the container and thus together the puncture cannula and the piston in the container in a direction of advance by pressure on a piston which is arranged in a container filled with the product. The processes of piercing and pouring out are therefore not exactly sequential, but also partly at the same time.

In the respective injection devices, the piston is propelled by means of a piston rod and a spring acting on the piston rod in the direction of advance of the piston. In the devices of DE 198 22 031 AI, the spring is received in a drive pot and presses the pot against a proximal end of the piston rod. The spring surrounds the simplified version of US Pat. No. 4,031,893 directly the piston rod and presses in the direction of advance against a radially outwardly projecting shoulder of the piston rod. The piston rod is either connected directly to the piston or to an intermediate piece which is permanently connected to the piston and serves as an adapter for adapting to different degrees of container filling.

In order to improve the handiness, there is a desire for devices for the administration of injectable products for a construction that is as compact as possible, in particular for a length that is as short as possible measured in the direction of advance of the piston. This desire exists in particular in the case of auto-injectors, since auto-injectors are generally longer than conventional injection devices, including simple syringes, because the puncture cannula must also be moved in the direction of advance relative to a housing of the respective device by the penetration depth desired for the injection.

It is therefore an object of the invention to help shorten the length of devices for administering injectable products measured in the direction of advance of the piston.

The invention is based on a device for the administration of an injectable product, which comprises a housing, a container for the product with a piston and a piston rod, and a spring acting on the piston rod. By moving the piston in a direction of advance, the product is poured out of the container. The spring accordingly acts on the piston rod in the direction of advance. The piston rod and the spring are components of a drive unit for the piston or already form such a drive unit alone. The device can also have a puncture cannula which points in the direction of advance.

In an initial state of the device, for example immediately before a product is administered, the device is “sharp”, ie the spring is tensioned and the The piston rod is held in a holding position against the force of the tensioned spring in a holding position. The holding engagement can exist directly between the housing and the piston rod or, more preferably, can only be effected between these two components via one or more transmission elements. The holding engagement is releasable.

According to the invention, the spring extends into the container, not only only during the pouring movement, but already in an initial state of the device before the drive unit is triggered. Usually, the piston does not end flush with the rear edge of the container with respect to the direction of advance, so that a space remains between the piston rear and the rear edge of the container. This space is used according to the invention to accommodate the spring at least over part of its axial length extending in the direction of advance. Compared to the known devices, the axial length of the device can therefore be shortened by the length by which the spring protrudes into the container in the direction of advance even in the holding position of the piston rod beyond the rear edge of the container. If the piston is flush with the rear edge of the container, it follows that the piston forms a cavity into which the spring and accordingly also the piston rod protrude.

The device can in particular be an injection device, preferably an injection pen. Since the spring acts on the piston rod in the direction of advance, a user of the device must perform the dispensing movement, i. H. do not carry out the forward movement of the piston rod and the piston yourself. He only has to trigger the drive unit, which then automatically drives the piston in the direction of advance.

In preferred embodiments, the device is an auto-injector which, after being triggered, automatically executes not only the dispensing movement, but also a puncturing movement of a puncture cannula connected to the product container, which is directed in the direction of advance. However, the injector does not necessarily have to have a puncture cannula. Product administration is also conceivable by means of a so-called pressure injection. If the autoinjector has a puncture cannula for preferably a subcutaneous injection, the drive unit can comprise a further spring which, as a puncture spring, brings about the puncturing movement of the puncture cannula, while the spring mentioned only fulfills the function of a dispensing spring which performs the dispensing movement, i.e. the propulsion of the piston in the Container, causes. In simple, likewise preferred versions, the spring mentioned is a puncture and discharge spring in one.

The device is preferably used in the self-administration of products. Preferred applications are, for example, diabetes therapy, osteoporosis therapy and treatment with growth hormones. The injectable product is therefore, for example, insulin, an osteoporosis preparation or a growth hormone.

The piston rod can be firmly connected to the piston. However, it preferably only presses loosely against the rear of the piston. At least in this preferred embodiment, it comprises a plunger with which it presses against the back of the piston during the dispensing movement and thereby moves the piston in the direction of propulsion. The spring is preferably supported on the back of the stamp. In order to save axial length, the punch should form the front end of the piston rod and advantageously be thin with a thickness of preferably less than 2 mm. The spring is preferably supported directly on the back of the plunger, so that its front end is only spaced from the back of the piston by the thickness of the plunger when the plunger presses against the back of the piston. The plunger preferably contacts the back of the piston in the holding position of the piston rod.

The piston rod preferably guides the spring axially. Here, the spring can surround the piston rod. It is preferred, however, that the piston rod surrounds the spring. In such designs, the piston rod is a sleeve, which in particular can be circular-cylindrical, with a sleeve jacket that can be perforated, but preferably is continuously smooth. Preferably protrudes at a front end of the sleeve from the sleeve jacket a shoulder radially inwards, on which the spring is supported in the direction of propulsion and which preferably also forms the mentioned stamp. The shoulder should accordingly form the front end of the sleeve jacket. The shoulder can form a bottom of the cup-shaped sleeve in this case. Instead, it can also be formed as a circumferential ring shoulder. It can even be formed only as a radially inwardly projecting web, wherein in such an embodiment preferably several of the shoulders project radially inward from the sleeve shell in order to support the spring as evenly as possible over the sleeve circumference.

For the holding engagement, the piston rod preferably has a holding shoulder which is formed in the holding engagement with a counter shoulder of the housing or preferably a bearing structure arranged between the housing and the piston rod. The holding shoulder can be in direct contact against the counter shoulder in the direction of advance or only via a transmission device, for example a ball or a cylindrical pin or several such bodies. By triggering the device, the blocking of the piston rod caused by the stop contact is released, so that the piston rod is driven in the direction of advance by the force of the spring.

The holding shoulder is preferably formed by a conical widening of the piston rod. The piston rod preferably runs out in the widening at its rear end. If, as is preferred, the piston rod is a sleeve, it advantageously runs out funnel-shaped to form the widening, i. H. it forms an axially short opening funnel at its rear edge.

In a particularly preferred embodiment, the piston rod is therefore a sleeve, the front end of which forms an inwardly projecting shoulder, preferably in the form of a closed base or an annular shoulder. In order to be able to hold the piston rod in a holding position against the force of the spring, the piston rod in preferred further developments is, as already mentioned, with at least one Provide holding shoulder, which preferably runs around. If necessary, several individual holding shoulders can also be provided distributed over the circumference of the sleeve. Such a design of the piston rod is already advantageous even without the feature according to the invention that the spring already projects into the container in the holding position of the piston rod.

In an alternative embodiment, in which a sleeve likewise forms the piston rod, the shoulder serving to support the spring and preferably also as a stamp protrudes outward beyond the shaft section of the sleeve. In such an embodiment, the spring surrounds the sleeve. The retention shoulder, if one is provided, may protrude radially inward over the sleeve shaft at the opposite end of the sleeve to form the retention engagement with a counter shoulder protruding into the sleeve, with the retention engagement between the shoulders as with the stronger one preferred version of the sleeve surrounding the spring can be formed.

The applicant reserves the right, by way of a divisional application, to also direct claims to an administration device which comprises a piston rod formed as a sleeve, but not necessarily the feature according to which the spring projects into the product container, although the combination is particularly preferred.

The piston rod formed as a sleeve can in particular be made in one piece from a metallic material. It is preferably obtained from a semi-finished product by shaping. Suitable semi-finished products are, for example, pipes which are cut to length by means of a separation process to form pieces of pipe of the length required for the piston rod. The shoulder on which the spring is supported and, if present, also the holding shoulder is or are formed by reshaping one end of the pipe section or both ends of the pipe section. A shoulder projecting radially outwards and also radially inwards over the sleeve shaft can be obtained by means of a bending deformation by means of a mold. Furthermore, deep drawing is also suitable as the forming process, with a semi-finished product being used as a semi-finished product. By deep drawing In particular, a pot-shaped piston rod can be formed with a shoulder running around the open end of the pot.

Preferred features of the invention are also described in the subclaims and their combinations. The features described there and the features described above complement one another in an advantageous manner.

Exemplary embodiments of the invention are explained below with reference to figures. Features that become apparent from the exemplary embodiments, individually and in each combination of features, advantageously further develop the subjects of the claims and also the embodiments described above. Show it:

1 shows an auto-injector in an initial state in which a drive unit of the injector is tensioned and secured, FIG. 2 shows the auto-injector with a tensioned but unlocked drive unit,

3 shows the unlocked autoinjector placed on a puncture site immediately before a puncture needle is inserted, FIG. 4 shows the autoinjector immediately after the puncture needle is inserted and immediately before the product is dispensed, FIG. 5 shows the autoinjector with a puncture needle inserted after the product has been dispensed, Auto injector after use and

Figure 7 shows a proximal part of a modified auto-injector.

FIG. 1 shows an auto-injector in a longitudinal sectional plane which contains a central axis of symmetry L of the injector, which is referred to below as the longitudinal axis L.

An envelope structure 1 forms a main part of a housing of the injector. The envelope structure 1 is used to grip the injector and to store its components. The envelope structure 1 is a circular cylindrical sleeve with the longitudinal axis L as an axis of symmetry. A bearing structure is accommodated in the envelope structure 1 so as to be movable along the longitudinal axis L relative to the envelope structure 1. The bearing structure is in two parts and consists of a distal part 5 and a proximal part 7, which are axially immovably connected to one another. The bearing structure 5, 7 is hollow cylindrical overall, in the exemplary embodiment circular cylindrical. In the bearing structure 5, 7, a container 2 filled with injectable product is accommodated so that it can move axially relative to the bearing structure 5, 7 in a direction of advance V. The container 2 is an ampoule. The product is stored in the container 2 between an outlet, which the container 2 has at a front, ie distal end, with respect to the direction of advance V, and a piston 3, which is accommodated in the container 2 in an axially slidable manner. At the front end of the container 2, a puncturing cannula 4 is attached pointing in the direction of advance V. The product is displaced from the container 2 by a pushing-out movement of the piston 3 in the direction of advance V and then poured out through the piercing cannula 4.

The discharge movement of the piston 3 is effected by means of a drive unit. The drive unit consists of a mechanical spring 15 and a piston rod 16. The piston rod 16 forms a plunger 17 on its front face with which it presses against the piston 3 in the direction of advance V. In addition to the pressure contact, there is no connection between the piston rod 16 and the piston 3.

In the state shown in FIG. 1, the piston rod 16 assumes an axial holding position in which it is held against the force of the tensioned spring 15 acting in the direction of advance V. For this purpose, the piston rod 16 is in a holding engagement with the bearing structure 5, 7. The bearing structure 5, 7 is itself prevented from moving in the advancing direction V relative to the envelope structure 1 by a positive fit. The positive connection exists between a front edge of the proximal part 7 and a shoulder which protrudes inwards from an inner surface of the envelope structure 1. A spring 22 presses the bearing structure 5, 7 into this stop contact with the envelope structure 1. The holding engagement of the piston rod 16 consists between a holding shoulder 18 of the piston rod 16 and directly a counter shoulder 8a of the proximal part 7 of the bearing structure 5, 7. The piston rod 16 tapers conically at its proximal end in a widening forming the holding shoulder 18. The sleeve-shaped proximal part 7 is axially slotted, so that tongue-like holding elements 8 are formed, each with a free proximal end. The holding elements 8 are elastically bendable. At its free proximal end, each of the holding elements 8 forms one of the counter shoulders 8a for the holding shoulder 18. The counter shoulders 8a face the holding shoulder in the direction of advance. The holding shoulder 18 has direct contact with the counter shoulders 8a.

In the holding position, the holding elements 8 are blocked in the holding engagement by a blocking device 10. The blocking device 10 is axially immovably connected to the envelope structure 1. In the exemplary embodiment, it is inserted through the open proximal end of the enveloping structure 1 into the enveloping structure 1 and latched to the enveloping structure 1. The blocking device 10 is a sleeve body and surrounds the holding elements 8 and blocks the holding elements 8 in the holding engagement by preventing the holding elements 8 from escaping radially outward under the pressure exerted by the spring 15 via the holding shoulder 18. The holding elements 8 are thickened radially outward at their free proximal ends, so that they are pressed radially inward into the holding engagement against a radially facing blocking surface of the blocking device 10. The blocking surface is an inner surface of the blocking device 10.

In the holding position, the spring 15, in the exemplary embodiment a helical spring, is tensioned axially between a proximal spring support 9 and the plunger 17, which thus forms a distal spring support.

In the holding position, the spring 15 extends from the proximal spring support 9 into the proximally open container 2 and projects almost up to the piston 3. The distal end of the piston 3 is axial only by the thickness of the plunger 17 spaced. The plunger 17 in turn forms a thin, flat bottom of the piston rod 16 pointing radially to the longitudinal axis L. The spring 15 is therefore brought as close as possible to the piston in order to obtain a drive unit and ultimately an injector with the shortest possible axial length , The stamp 17 ideally has just such a thickness as is required for the support of the tensioned spring 15. The lower limit for the thickness of the spring support formed by the stamp 17 is thus only given by the inevitably required strength and an addition required for safety reasons.

In particular for slim containers 2 with a correspondingly small hollow cross section, it is advantageous if the piston rod 16 is a metal sleeve. Compared to plastic parts, metal sleeves have greater strength with less wall thickness. Correspondingly thicker, the spring 15 lying against the sleeve shaft of the piston rod 16 and guided by the sleeve shaft can be made. The spring stiffness and thus the spring force exerted during propulsion can advantageously be greater than with thick-walled sleeves. Given a predetermined hollow cross section of the container 2, sleeves with a small wall thickness forming the piston rod 16 are therefore preferred. As the hollow cross section of the container 2 increases, the piston rod 16 can be designed with a correspondingly enlarged outer circumference. If the hollow cross section of the container 2 exceeds a certain size, the piston rod 16 in the preferred embodiment can also be made as a sleeve as a plastic sleeve.

The piston rod 16 is a deep-drawn metal sleeve made from semi-finished plates. It extends axially from the piston 3 to almost the spring support 9, it being removed from the spring support 9 only by the axial distance required for engaging behind the counter shoulder 8a. In the tensioned state of the spring 15, the spring 15 and the piston rod 16 thus have essentially the same axial length. The spring support 9 formed as a sleeve bottom forms the end of the bearing structure 5, 7.

A securing element 13, in the exemplary embodiment a securing cap, closes the housing of the injector formed by the envelope structure 1 and the blocking device 10 from. The securing element 13 is releasably attached to the blocking device 10 by means of a locking engagement. It can be pulled off by the user by hand in order to unlock the injector and thereby "prepare" for product administration. In the initial state shown in FIG. 1, an axially projecting web 14 of the securing element 13 extends the blocking surface of the blocking device 10 in the proximal direction ,

2 shows the auto-injector after the securing element 13 has been removed in the unlocked and thus “armed” state. By removing the securing element 13, a depression 11 of the blocking device 10 is exposed. The depression 11 is formed in an axial extension proximal to the blocking surface of the blocking device 10 The blocking device 10 widens against the advancing direction V from its blocking surface via a shoulder 12 into the recess 11. The shoulder 12 forms an abrupt transition from a distal section forming the blocking surface to a proximal section of the blocking device 10 forming the recess 11 14 of the securing element 13 is accordingly an annular web which, in the attached state, fills the portion of the blocking device 10 which forms the recess 11 up to the radial height of the blocking surface.

In the unlocked state, the bearing structure 5, 7 can be moved as a whole relative to the envelope structure 1 and in particular the blocking device 10 against the direction of advance V, so that the holding elements 8 with their free proximal ends get behind the shoulder 12 into the recess 11 and there after can be moved radially outward from the holding engagement. The necessary path length 1 of the backward movement is predetermined by a stop surface of the blocking device 10 pointing in the direction of advance V and an axially facing counter surface of the proximal part 7 pointing against the direction of advance V.

At the distal end of the sheath structure 1, a needle protection sleeve 21 projects into the sheath structure 1, which is also open there. The sheath structure 1 supports the needle protection sleeve 21 in an axially movable manner. The spring 22, on the one hand on the envelope structure 1 and on the other hand on the Needle protection sleeve 21 is supported, the needle protection sleeve clamps in a distal position relative to the envelope structure 1. The spring 22 presses the needle protection sleeve 21 against a stop formed by the bearing structure 5, 7. The bearing structure 5, 7 has in its distal region an outwardly bendable blocking element 6, which is formed in one piece by the distal part 5 in the manner of a tongue which projects in the direction of advance V. After administration of the product, the blocking element 6 serves to block the needle protection sleeve 21 in its protective position, ie in its position distal with respect to the sheath structure 1, and thereby to protect the user from the puncture cannula 4.

A cannula sleeve 20 is placed on the distal end of the container 2 and over the piercing cannula 4. The cannula sleeve 20 firstly places the container 2 in the bearing structure 5, 7 and has the necessary axial rigidity for this. It also keeps the puncture cannula 4 sterile. On the other hand, their axial rigidity is not so great that it impedes or could even prevent the propulsion of the container 2 in the bearing structure 5, 7 after the injector has been triggered. The needle cover 20 can be, for example, an axially flexible rubber hose or a bellows.

The use of the auto injector of the embodiment is explained below.

The injector is delivered to the user in the initial state shown in FIG. 1, the delivery state. The container 2 is filled beforehand with a quantity of product which is intended for exactly one injection. The drive unit is loaded, i. H. the piston rod 16 is in the holding engagement and the spring 15 is tensioned.

By releasing the securing element 13 from the blocking device 10, the user unlocks the injector which, as shown in FIG. 2, is then in the unlocked state. In the unlocked state, the injector with the needle protection sleeve 20 is placed vertically on the skin at the desired insertion point and pressed against the skin. The envelope structure 1 serves as a handle. As a result of increasing pressure, the needle protection sleeve 21 moves deeper into the envelope structure 1 against the force of the spring 22 in a first phase of pressing. As soon as the bearing structure 5, 7 has contact with the skin at its proximal end as a result of the pressing, the needle protection sleeve 21 and the bearing structure 5, 7 are moved together in a subsequent, second phase relative to the envelope structure 1 against the direction of advance V by further pressing. In the course of this relative movement, the holding elements 8 slide along the blocking surface of the blocking device 10 in the proximal direction and finally reach the region of the depression 11. The relative movement is limited by the bearing structure 5, 7 abutting the blocking device 10. Shortly before the stop, but at the latest at the moment of the stop, the holding elements 8 deflect radially outward into the depression 11 under the action of the force exerted by the spring 15 via the holding shoulder 18, so that the holding engagement is released. The evasive movement of the holding elements 8 is supported by their own elastic restoring forces. The holding shoulder 18 and / or the counter shoulders 8a are inclined to the longitudinal axis L, so that they can slide against one another as soon as the holding elements 8 can escape into the depression 11. At least a jamming of the holding shoulder 18 and / or the counter shoulders 8a prevents jamming.

FIG. 3 shows the injector in the state immediately after the holding engagement has been released and before the advancing movement of the piston rod 16 begins. From this transitional state, the piston rod 16 immediately changes to the forward movement under the pressure of the spring 15. The bearing structure 5, 7 is held in its proximal position relative to the envelope structure 1 by pressing the injector against the skin. The piston rod 16 moving in the direction of advance presses with its plunger 17 against the piston 3. Due to the static friction between the piston 3 and the container 2, the container 2 in the bearing structure 5, 7 is moved in the direction of advance V. The piercing cannula 4 executes the movement together with the container 2 and pierces the cannula sleeve 20 in the course of this piercing movement in order to subsequently penetrate the skin and preferably subcutaneously into the tissue. In the course of the piercing movement, the container 2 pushes the blocking element 6 and thereby bends it outwards. Furthermore, the cannula cover 20 is compressed. The cannula sleeve 20 limits the piercing movement and thus also determines the penetration depth of the piercing cannula 4.

FIG. 4 shows the injector after the piercing movement has been carried out, but before the product is dispensed. The piercing movement of the piston rod 16 changes at the latest after the piercing movement of the piercing cannula 4 has been carried out into the dispensing movement, in the course of which the product is dispensed. The piercing movement of the piercing cannula 4 is ideally completed before the dispensing movement of the piston 3 begins. The piston rod 16 effects both movements by means of its own propulsion movement. In this sense, the spring 15 forms a puncturing and dispensing spring.

FIG. 5 shows the injector after the container 2 has been completely emptied; H. after the end of the distribution, but before pulling the puncture cannula 4 out of the tissue. If the puncture cannula 4 is now pulled out of the tissue, the needle protection sleeve 21 moves in the advancing direction V due to the force of the spring 22 relative to the sheath structure 1. In the course of this movement, the needle protection sleeve 21 comes back in front of the blocking element 6 with a stop shoulder in the advancing direction V. The blocking element 6 and the relevant stop shoulder of the needle protection sleeve 21 then lie axially opposite one another, so that the blocking element 6 prevents the needle protection sleeve 21 from being retracted and blocks the needle protection sleeve 21 in its protective position.

FIG. 6 shows the injector after use with a blocked needle protection sleeve 21. The injector is designed as a disposable device and is disposed of after a single use. FIG. 7 shows the proximal section of a modified auto-injector, which differs from the auto-injector of FIGS. 1 to 6 only in relation to the plunger of the piston rod 16 and the holding engagement between the piston rod 16 and the bearing structure 5, 7. The stamp 17 'of the modified embodiment is not formed by the sleeve shaft of the piston rod 16 as a continuous bottom, but as a circumferential ring shoulder. The piston rod 16 of the modified embodiment is again a metal sleeve. However, it is formed by forming from a piece of pipe. The sleeve shaft corresponds to the undeformed piece of pipe. The stamp 17 'and the holding shoulder 18 are each formed by bending, the stamp 17' by pressing a hollow mold and the holding shoulder 18 by pressing against an expanding shape.

In the modified exemplary embodiment, the holding engagement does not exist directly between the holding shoulder 18 and the bearing structure 5, 7, but is effected via one or in the exemplary embodiment a plurality of transmission elements 19. The transmission elements 19 can be balls or cylindrical pins, for example, which are pressed by the spring 15 via the holding shoulder 18 in the advancing direction V against a counter shoulder of the bearing structure 5, 7. The holding engagement is released in the same way as in the auto-injector of FIGS. 1 to 6, with the only difference that it is not a holding element 8 formed by the bearing structure 5, 7, but the transmission elements 19 which deflect into the recess 11 in the blocking device 10.

Claims

claims

A device for the administration of an injectable product, comprising: a) a housing (1, 10) b) a movably mounted product container (2) accommodated by the housing (1, 10), in which a piston (3) into a The direction of advance (V) is movably received in order to dispense product, c) a piston rod (16) acting in the direction of advance (V) on the piston (3) d) and a spring acting in the direction of advance (V) on the piston rod (16) (15), e) the piston rod (16) being releasably held in a holding position against the force of the spring (15) in a holding position, characterized in that f) the spring (15) in the holding position in the container (2) protrudes.

2. Device according to claim 1, characterized in that the piston rod (16) has a plunger (17; 17 ') with which it presses against the piston (3) in the direction of advance (V) for distribution of the product.

3. Device according to the preceding claim, characterized in that the plunger (17; 17 ') forms the front end face of the piston rod (16) in the direction of advance (V).

4. Device according to one of the preceding claims, characterized in that the piston rod (16) surrounds the spring (15).

5. Device according to the preceding claim, characterized in that the piston rod (16) is a sleeve and the spring (15) is supported on a shoulder which projects inwards at a front end of the sleeve in the forward direction (V) and preferably the foremost Forms the end face of the piston rod (16).

6. Device according to one of the preceding claims, characterized in that the piston rod (16) has a holding shoulder (18) and the holding shoulder (18) to the direction of advance (V) preferably inclined with a directional component parallel and a directional component perpendicular to the direction of advance (V ) runs.

7. Device according to one of the preceding claims, characterized in that the piston rod (16) is a sleeve structure obtained by plastic deformation, preferably cold deformation, from a semifinished product.

8. Device according to one of the preceding claims, characterized in that the piston rod (16) is formed in one piece.

9. Device according to one of the preceding claims, characterized in that a metallic material forms the piston rod (16).

10. Device according to one of the preceding claims, characterized in that the piston rod (16) is a deep-drawn part.

11. The device according to one of claims 1 to 9, characterized in that the piston rod (16) was obtained from a tube piece by reshaping at least one axial end, preferably both ends, of the tube piece.

12. The device according to one of the preceding claims further comprising a bearing structure (5, 7) which supports the product container (2) in the Vortriebsrichtαng (V) movable.

13. The device according to the preceding claim, characterized in that the bearing structure (5, 7) forms a support (9) for the spring (15).

14. Device according to one of the two preceding claims, characterized in that the housing (1, 10) supports the bearing structure (5, 7) movably against the direction of advance (V).

15. Device according to one of the three preceding claims, characterized in that the piston rod (16) with the bearing structure (5, 7) is in the holding engagement.

16. Device according to one of the preceding claims, characterized in that the piston rod (16) has a holding shoulder (18), that a counter shoulder (8a; 8a ') is provided, which is at least in the holding position of the piston rod (16) on the housing (1, 10) in the direction of advance (V) is fixed so that it cannot move or is formed by the housing, and that the holding shoulder (18) and the counter shoulder (8a; 8a ') are in the holding engagement.

17. The device according to the preceding claim, characterized in that the holding shoulder (18) and the counter shoulder (8a; 8a ') are in direct contact with each other in the holding engagement or a transmission device (19) the holding engagement between the engagement shoulder (18) and Counter shoulder (8a; 8a ') causes.

18. Device according to the preceding claim, characterized in that a blocking device (10) is provided which blocks one of the holding shoulder (18) and counter shoulder (8a) in the holding engagement.