EP0028727B1 - Dispenser for pasty produce - Google Patents

Abstract

A dispenser for pasty products has a cylindrical body with an open bottom and an outlet in its top. A piston that closes the bottom of the body, cooperating with it to define a chamber, is slidable upward in the body for expelling contents of the chamber out of the outlet. An actuator on the exterior of the body, movable in opposite directions, is manually movable to one limit of its motion and biased to the other limit. A rod connected with the actuator and movable lengthwise up and down in the body has a unidirectional driving connection with the piston that constrains the piston to move upward with it but allows it to move down relative to the piston. A check valve associated with the outlet opens to allow discharge of chamber contents but closes to block flow into the chamber, thus enabling atmospheric pressure to hold the piston against downward motion. Several advantageous unidirectional connections are disclosed.

Description

The invention relates to a dispenser for pasty products, consisting of a container open at the bottom with a dispensing opening and with a movable piston closing off the lower container opening and an actuating device arranged outside the container interior for manually pressing out the container contents by means of the piston through the dispensing opening, whereby the actuating device has a manually operable pushbutton, which cooperates with a restoring element and has a rod coupled therewith, projecting into the interior of the container, from a coupling device designed as a relative movement between the rod and the piston, which only allows unidirectional movement, to establish an operative connection between the by means of the Hand-operated organ up and down movable rod and the piston, and a device for preventing the piston from dropping from a position once reached.

From US-AS 3 255 935 a dispenser of the type described in the opening paragraph is known. The connection device for establishing an operative connection in this known dispenser consists of four resilient tongues, two of which are diametrically opposed to each other. The tongues are firmly attached at one end to the underside of the piston and each with their other ends directed obliquely downward and press with their end edges against the rod. The device for preventing the piston from sinking from a position once reached likewise consists of four resilient tongues, diametrically opposed in pairs, which are each fixedly attached to the piston and are directed obliquely downward with the end edges of their other end and against the Press the inner wall of the container.

If the contents of the container should emerge from the interior of the container, press the push button, which moves the rod downwards. The piston remains stationary in position during this downward movement of the rod, since the tongues spreading into the container wall prevent a downward movement. The actual conveying movement is brought about by the spring in the push button arrangement, since this pulls the rod upwards. During the upward movement, the tongues assigned to the rod expand into the lateral surface of the rod and thus couple the rod to the piston. As soon as the piston moves upward, the tongues assigned to the inner wall of the container loosen from their spread position and graze along the inner wall of the container during the upward movement of the piston.

This known dispenser has the disadvantage that the tongues, which are all formed in one piece on a ring, must be designed very precisely in terms of their spring force and their dimensions, since otherwise an easy actuation of the dispenser is not possible. If e.g. If the springs assigned to the inner walls of the container have too great a spring force, it can happen that the spring in the push button is not able to lift the piston. On the other hand, if the spring length is not exactly adhered to, there is a risk that the rod pushed downward will move the piston downward as a result of the friction between the outer surface of the rod and the bore wall of the piston, since the tongue assigned to the inner wall of the container is too long due to its length cannot spread into the inner wall of the container. The corresponding disadvantages also arise if the tongues assigned to the rod have the errors listed above.

A dispenser for flowable materials is known from US Pat. No. 3,361,305, in which a container open at the bottom with a dispensing opening and with a movable piston closing off the lower container opening and an actuating device arranged outside the container interior for manually pressing out the container contents by means of of the piston are provided through the dispensing opening, but in this known dispenser the atmospheric pressure acting on the underside of the piston is used to move the piston upwards against a negative pressure to be created in a pumping chamber above the container interior and thereby to To convey donating material into the pumping chamber and from there to subsequently convey it outwards from the pumping chamber through the dispensing opening by means of the actuating device. In this known dispenser, the piston is not mechanically coupled to the actuating device, and in particular not by means of a rod which can be connected to the piston by a coupling device when it moves upward. In this known dispenser, check valves must be provided both at the transition from the interior of the container to the pumping chamber and at the dispensing opening from the pumping chamber to the environment, on the one hand to enable the formation of a negative pressure in the pumping chamber and on the other hand to transport material located in the pumping chamber outwards through the To ensure donation opening and to prevent the material in the pump chamber from being pushed back into the interior of the container. In this known dispenser there is no mechanical force acting on the piston inside the container, and in particular when the actuating device (pump chamber device) is actuated there are no forces acting mechanically on the piston which push the piston further downwards from a position once it has been assumed would. Therefore, in this known dispenser no devices for holding the piston in a position once taken are provided or required.

From DE-A-2 015 441 a dosing device for liquid media, in particular for a perm chemical, is known, which is designed as a liquid container with a dosing space downstream of it. The interior of the liquid container is connected to the metering chamber via a connecting channel. On the other hand, the dosing room is provided with a screen plate on its dispensing side, to which an application sponge is attached. The connecting channel between the interior of the container and the dosing space can be closed by a sealing plug which is attached to the free end of a two-armed lever, which is pivotably mounted on a wall of the dosing space and whose other free end is provided with a handle protruding from the dosing space. By actuating the handle, the sealing plug can either be lifted off the connecting channel or pressed onto it. In this known dosing device, the transition of the chemical from the inside of the container into the dosing space is to be accomplished in that the dosing device is held in such a way that the dosing space connects under the container. When the sealing plug is lifted off the connection channel, the chemical then runs down through the connection channel into the dosing chamber and from there through the sieve plate into the application sponge. After swiveling the sealing plug into the closed position, chemicals cannot flow into the metering chamber any further. The chemical in the application sponge can then be applied to the hair to be treated. Apart from the fact that it is questionable whether this known dosing device works at all, since a connection of the interior of the container to the atmosphere is not disclosed, no device is provided in this known dosing device by means of which the contents of the container are forced into the dosing chamber and from is promoted to the outside world. In particular, no displaceable piston is provided in the interior of the container, the movement of which could promote the contents of the container to the outside. The contents of the container should only flow outwards under the force of gravity after opening the connecting channel. Due to the lack of an actuating device which effects the conveyance of the container contents, this known metering device differs fundamentally from dispensers with forced conveyance of the container contents and in particular from dispensers of the type of the present invention.

From US-A-1 659 254 a soap dispenser for dispensing pasty soap is known, which has a soap container with a discharge screw rotatably arranged on the bottom inside and a discharge opening arranged at one end of the discharge screw. Provided in the cylindrical container is a plate which essentially covers its cross section and has a central opening. Through this central opening, a threaded rod projects coaxially to the container, which is rotatably mounted in the container and which is also set in rotation by means of a gear mechanism when the discharge screw rotates. The rotation of the threaded rod is converted into a downward movement of the plate in the container in that two claws are pivotably mounted on the plate diametrically opposite each other, each being designed as a two-armed lever. One free end of each claw has teeth that can be brought into engagement with the thread of the rod. The other free end of each rod is designed as a handle. When the claws are pivoted into their engagement position, in which they engage in the thread of the rod, they are moved along the threaded rod, and with them, because the plate is secured against rotation axially on the inner wall of the container Plate. During this longitudinal movement, the plate pushes the soap underneath down towards the discharge screw. As soon as the content of the soap dispenser has been used up and new soap is to be refilled into the container from above, the claws on the plate can be pivoted by hand by pulling the handles of the claws upwards into a release position in which the teeth of the claws do not engage more in the thread of the rod. The plate with the claws can then be lifted out of the container along the rod. After soap has been poured in, the plate is then reinserted from above and brought back into engagement with the threaded rod by pivoting the claw. This claw arrangement is not a device for connecting a reciprocating rod to a piston always and only when the rod moves in one direction and not in the opposite direction. The known device serves exclusively to produce a screw connection between the plate and the threaded rod that is permanently engaged during the operation of the device and not a coupling device that automatically detaches itself from the movement of a reciprocating rod in one direction of movement and engages again under the effect of gravity in the opposite direction of movement .

The invention has for its object to provide a dispenser of the type mentioned in the preamble of claim 1, in which the piston is prevented in a simple manner from falling from a position once reached and which is easy and reliable to handle.

This object is achieved according to the invention in that the device for preventing the piston from sinking is designed as a check valve and in that the actuating device has a lever device by means of which the rod can be moved upwards when the push button is pressed.

The arrangement of a check valve and the arrangement of a lever device in the actuating device, by means of which the rod can be moved upward when a push button is pressed, ensures reliable holding of the piston in a position once reached and prevents the piston from dropping out of this position and it is further ensured that when the actuating device is actuated, the piston is pulled up during the actuating process and thus the contents of the dispenser are dispensed during the actuation of the device and not in a subsequent process after actuation. The result of the actuation is thus immediately visible and the amount donated can still be influenced during the donation by a corresponding observation of the amount of the escaping material by a correspondingly dependent dosage of the actuation movement.

A favorable embodiment can be provided in that the check valve is provided in the area of the dispensing opening.

Depending on the viscosity of the container contents, it may be favorable that the check valve is designed as a flap check valve arrangement with at least one check valve, or alternatively that the check valve is designed as a ball check valve.

A favorable design can be seen in the fact that the piston has at least one recess, through which the rod protrudes and in which the coupling device is arranged. This measure leads to a very compact construction of the piston, whereby a reduction in the container length is achieved.

An advantageous embodiment of the invention can be seen in the fact that the coupling device is designed as a friction lock and has at least one locking element. A design as a friction lock ensures, on the one hand, a secure coupling connection between the rod and the piston when the rod moves in one direction and, on the other hand, an unimpeded movement of the rod against the conveying direction.

It can be advantageous that the at least one locking member is designed at a pivot point as a friction block that is rotatably suspended above its center of gravity.

A favorable constructive solution can be seen in the fact that the friction block has a convex friction surface on one side facing the rod, which frictionally interacts with the lateral surface of the rod when the rod moves in the exit direction. This form of training can be favorable for pasty container contents with a low viscosity.

In another embodiment variant, it can be provided that the friction block is wedge-shaped on its side faces and can be brought into engagement with a groove which is shaped in the form and is formed in the rod parallel to the longitudinal axis of the rod in such a way that a frictional engagement when the rod moves in the exit direction Active connection between the side flanks of the groove and the side surfaces of the friction block can be established. This design variant can be favorable for pasty container contents of high viscosity, since in addition to the frictional engagement there is also a clamping effect, as a result of which a greater frictional connection can be achieved.

An alternative embodiment of the friction lock is given in that at least one locking member is designed as a resilient projection which projects from the piston, projects inward into the recess and is curved against the exit direction and rests resiliently on the lateral surface of the rod in such a way that one Movement of the rod in the exit direction a frictional operative connection between the projection and the rod can be produced. Because the blocking member is formed directly on the piston, it can be formed in one piece with the piston, which considerably reduces the manufacturing costs.

As an alternative to the friction locks, it can be favorable for the coupling device to be designed as a positive locking device. This can be particularly appropriate for pasty products with a very high viscosity.

A favorable design can consist in the fact that the hem locking mechanism consists of at least one resilient tongue.

It may be favorable here for the at least one tongue to be fixedly attached to the piston at one end and to rest against the rod with an end edge of its other end which extends transversely to the longitudinal axis of the rod and which is bent counter to the exit direction.

In connection with the previously described design variations of the friction lock and the positive locking, it can be favorable for the rod to have a smooth outer surface. As an alternative to this, it can be favorable for the rod to have groove-shaped depressions running on the lateral surface transverse to the longitudinal axis of the rod. A further alternative can provide that the rod has a roughened jacket fold.

A favorable second variant of a positive locking mechanism can be provided in that the positive locking mechanism has at least one protrusion formed in one piece on the piston and protruding into the recess and that the rod is designed as a toothed rack with teeth directed in the exit direction. In this case, an advantageous constructive embodiment is provided in that the projection has a first surface facing the exit direction and inclined to the rod and a second surface which is at an angle to the first surface and is arranged perpendicular to the exit direction. This arrangement ensures a secure positive fit between the rod and the projection formed on the piston.

It is advantageous that the size and shape of the recess in the piston is such that the teeth of the rod and the projection can be disengaged when moving against the exit direction. This training is particularly simple and inexpensive to manufacture.

Another favorable variant of the dispenser according to the invention can be seen in the fact that the coupling device is designed as a hook ratchet.

It may be advantageous that the hook ratchet has at least one hook-shaped projection formed on the piston and protruding into the recess and directed against the exit direction, and that the rod is designed as a toothed rack with teeth directed in the exit direction, which when the rod moves in the exit direction engage with the hook-shaped projection. This design variant also enables an unimpeded movement of the rod downwards and then, at the start of the upward movement, a secure operative connection between the rod and the piston.

A particularly good function of the dispenser can be achieved in that the piston has on its side facing the container contents a sealing collar which closely surrounds the rod.

• Fig. 1 eine schematische Schnittdarstellung eines erfindungsgemässen Spenders mit Spendeöffnung, Druckknopfanordnung, Hebelvorrichtung, Stange und Kolben,
• Fig. 2 ein erstes Ausführungsbeispiel einer Kupplungsvorrichtung als ein Reibgesperre mit schwenkbarem Sperrorgan,
• Fig. 3 ein zweites Ausführungsbeispiel der Kupplungsvorrichtung als eine Variante des Reibgesperres nach Fig. 2,
• Fig. 4 einen Schnitt durch das Reibgesperre aus Fig. 3 entlang der Linie IV-IV,
• Fig. 5 ein drittes Ausführungsbeispiel der Kupplungsvorrichtung als ein Reibgesperre mit einstückig an dem Kolben angeformtem Sperrorgan,
• Fig. 6a ein viertes Ausführungsbeispiel der Kupplungsvorrichtung als ein Formschlussgesperre,
• Fig. 6b eine Draufsicht auf eine Federplatte,
• Fig. 7 ein fünftes Ausführungsbeispiel der Kupplungsvorrichtung als ein alternatives Formschlussgesperre,
• Fig. 8 ein sechstes Ausführungsbeispiel der Kupplungsvorrichtung als ein Hakengesperre.

Various exemplary embodiments of the invention are described below with reference to the drawing. Show it:

• 1 is a schematic sectional view of a dispenser according to the invention with dispensing opening, push button arrangement, lever device, rod and piston,
• 2 shows a first embodiment of a coupling device as a friction lock with a pivotable locking member,
• 3 shows a second exemplary embodiment of the coupling device as a variant of the friction lock according to FIG. 2,
• 4 shows a section through the friction lock from FIG. 3 along the line IV-IV,
• 5 shows a third exemplary embodiment of the coupling device as a friction lock with a blocking member molded integrally on the piston,
• 6a shows a fourth embodiment of the coupling device as a positive locking,
• 6b is a plan view of a spring plate,
• 7 shows a fifth exemplary embodiment of the coupling device as an alternative positive locking mechanism,
• Fig. 8 shows a sixth embodiment of the coupling device as a hook ratchet.

In Fig. 1, a dispenser 1 is shown schematically in section. The dispenser 1 has a container 2 which has a cylindrical shape in the exemplary embodiment shown. The container is open at the bottom, this opening being closed by a piston 6 which serves as the container bottom and can be moved upwards. The piston 6 can be moved upwards by means of an actuating device 3, which is arranged outside the container interior. The movement of the piston 6 takes place via a rod 8, which is pressed down by the actuating device 3 by means of a push button 4 or pulled in the exit direction 25. A connecting device for establishing an operative connection between the rod 8 and the piston 6, which consists of a coupling device 5, is arranged on the piston 6. The dispenser 1 has a dispensing opening 9 at the top next to the actuating device 3. In this dispensing opening 9 there is a flap check valve 7 with a check flap 28 which can be swung open in the exit direction. This flap check valve serves to prevent the piston 6 from dropping from a position once reached. A closure cap 37 is placed on the dispensing opening 9 and protects the contents of the dispensing opening against drying out or soiling.

The actuating device 3 has a lever device 38. The lever device 38 consists of a lever 39 which is rotatably mounted on a lever pivot point 40 and which is fastened on the one hand to the part of the rod 8 projecting into the actuating device and on the other hand to a fastening point on a push button 4, in each case below it. A reset member 26 is arranged in this embodiment so that it pushes the rod down. If one presses the button 4, the rod 8 is thereby pulled upwards and the coupling device 5, which can exist according to one of the exemplary embodiments described below, is activated and an operative connection is established between the rod 8 and the piston 6, so that simultaneously with the Movement of the push button 4 down the container contents emerges from the dispensing opening 9.

2 shows a first exemplary embodiment of a coupling device 5. In this embodiment, the clutch device is designed as a friction lock 10. The friction lock 10 is arranged in a recess 11 of the piston 6 and consists of a locking member 12 which is rotatably mounted at a pivot point 21 above its center of gravity. In the variant of the friction lock 10 shown in FIG. 2, the locking member is designed as a friction block 12, the friction block 12 having a convexly shaped friction surface 15 on a side facing the rod 8. The center of gravity s of the semicircular friction block is located on the side facing away from the rod 8 of a perpendicular through the pivot point 21. This measure ensures that the friction block 12 is always in contact with the rod 8. The training example in FIG. 2 shows an embodiment of a friction lock with two diametrically opposite friction blocks 12. However, training variants with only one friction block as well as with more than two diametrically opposed friction blocks are also possible. With the training shown Example of use, the rod 8 on the lateral surface transverse to the longitudinal axis of the groove-shaped recesses 16. On the side of the piston facing the container content, a sealing collar 18 is formed on the recess 11, which serves to ensure that no air can penetrate into the interior through the recess 11.

FIG. 3 shows a second exemplary embodiment of the coupling device as a variant of the friction lock according to FIG. 2. In contrast to the friction lock from FIG. 2, the friction block 12 'in this variant is wedge-shaped, the friction block 12' interacting with a groove 17 which is trapezoidal in cross section and extends over the entire length of the rod 8 such that the side flanks 23 the groove and the wedge-shaped side surfaces 22 of the friction block 12 'come into frictional as well as clamping engagement with each other. Also in this case, because also in the following exemplary embodiments of the coupling device, the piston 6 is provided on its side facing the container contents at the recess 11 with a sealing collar 18 in order to seal the container contents against the external atmosphere.

FIG. 4 shows a section through the friction lock according to FIG. 3 along the line IV-IV. This sectional view clearly shows that the side flanks 23 of the groove 17 are completely in contact with the side surfaces 22 of the friction block; since the friction block 12 'is thus only supported by the side flanks of the groove 17, in addition to the frictional engagement, a very effective clamping engagement is also obtained, which is released again as soon as the rod is moved against the exit direction 25.

In Fig. 5, a third embodiment of the clutch device is shown as a friction lock. In this embodiment example, the locking member 12 "is designed as a resilient projection 14 projecting from the piston 6, protruding inward into the recess 11 and bent against the exit direction 25, which rests resiliently on the lateral surface of the rod such that when the A friction lock with two diametrically opposite projections is shown in Fig. 5. However, it is also possible to design the projection as a type of sleeve which completely surrounds the rod.

To increase the effectiveness of the coupling device between the rod and the piston 6, the side of the projection 14 facing the rod 8 can be provided with protruding catches 13 in a further embodiment.

6a shows a fourth exemplary embodiment of the coupling as a positive locking mechanism 20. The positive locking mechanism has a plurality of resilient tongues 29 which are directed towards a central recess and which are integrally connected to one another at their end 30 facing away from the central recess to form a spring plate. The spring plate is fastened in the recess 11 of the piston 6 in such a way that the ends of the resilient tongues facing away from the central bore are fixed in place on the piston 6. The central recess, which is formed by the tongues 29 striving towards one another, has a smaller dimension than the diameter of the rod 8. The resilient tongues 29 are therefore bent downwards by the rod 8 and each lie on the rod 8 facing it End 31 arranged, extending transversely to the longitudinal axis of the rod end edge 32 resiliently on the rod 8.

6b shows a spring plate consisting of eight tongues 29 arranged in a star shape relative to one another. The tongues 29 are each integrally connected to one another at their ends 30 used by the rod 8.

FIG. 7 shows a fifth exemplary embodiment of the coupling device as an alternative positive locking mechanism to the positive locking mechanism from FIG. 6. In this embodiment example, the piston 6 has a protrusion 33 projecting into the recess 11, which protrudes through a first surface 34 which faces towards the exit direction 25 and is inclined to the rod, and through a second surface which is at an angle to the first surface 34 and perpendicular to the exit direction 25 arranged surface 35 is formed. In this exemplary embodiment, the rod 8 is designed as a toothed rack 8 ′ with teeth 24 directed in the exit direction 25. The size and shape of the recess 11 in the piston 6 is shaped such that the teeth 24 of the rod 8 and the projection 33 can be disengaged when the rod moves against the exit direction 25. The sealing collar 18 is formed elastically in this embodiment.

Fig. 8 shows a sixth embodiment of the coupling device, which is designed as a hook ratchet 27 in this variant. For this purpose, the piston 6 has a hook-shaped projection which is integrally and resiliently formed on the piston 6 and projects obliquely downward into the recess 11. The rod 8 is designed in the same way as a rack 8 'as in the exemplary embodiment according to FIG. 7. If the rod is moved downward as a result of pressure on the push button 4, the teeth 24 push back the hook-shaped projection 36; whereby the rod 8 can perform its downward movement freely. If the rod 8 is moved upward, the hook-shaped projection 36 hooks into the rack 8 and thus couples the rod to the piston.

Claims (22)

1. A dispenser for pasty products, consisting of a container (2) open at the bottom and having a dispensing opening (9) and a movable piston (6) which closes off the opening at the bottom of the container and an actuator mechanism (3) arranged outside the interior of the container for effecting manually the expression of the contents of the container by means of the piston (6) through the dispensing opening (9), the actuator mechanism (3) exhibiting a pushbutton (4) which may be actuated by hand and cooperates with a return member and has coupled to it a rod (8) projecting into the interior of the container, of a connecting device constructed as a coupling device (5) which permits relative motion between the rod (8) and the piston (6) in one direction only, for the production of an operative connection between the rod (8) which may be moved up and down by means of the member actuable by hand, and the piston (6), and of a device for preventing sinking of the piston from a position once reached, characterized in that the device for preventing sinking of the piston (6) is constructed as a non-return valve (7, 7') and that the actuator mechanism (3) exhibits a lever mechanism (38) through which the rod (8) may be moved upwards upon pressing the pushbutton (4).

2. A dispenser as in Claim 1, characterized in that the non-return valve (7, 7') is provided in the region of the dispensing opening (9).

3. A dispenser as in Claim 1 or 2, characterized in that the non-return valve (7) is constructed as a flap non-return valve arrangement (7) having at least one non-return flap (28).

4. A dispenser as in Claim 1 or 2, characterized in that the non-return valve (7') is constructed as a ball non-return valve (7').

5. A dispenser as in at least one of the Claims 1 to 4, characterized in that the piston (6) exhibits at least one recess (11) through which the rod (8) projects and in which the coupling device (5) is arranged.

6. A dispenser as in at least one of the Claims 1 to 5, characterized in that the coupling device (5) is constructed as a friction ratchet mechanism (10) and exhibits at least one catch member (12, 12', 12").

7. A dispenser as in at least one of the Claims 1 to 5, characterized in that at least one catch member (12, 12') is constructed as a friction block (12,12') supported to be able to turn about a centre (21) above its centre of gravity.

8. A dispenser as in Claim 7, characterized in that the friction block (12) exhibits on one side next to the rod (8) a friction area (15) of convex shape, which cooperates by frictional engagement with the surface of the rod (8) if the rod is moved in the discharge direction (25).

9. A dispenser as in Claim 7, characterized in that the friction block (12') is constructed with a wedge shape at its sidefaces (22) and may be brought into engagement with a groove (17) shaped to correspond with that shape and constructed in the rod (8) in parallel with the longitudinal axis of the rod, in such a way that upon movement of the rod (8) in the discharge direction (25) an operative connection by frictional engagement may be produced between the sidefaces (23) of the groove (17) and the sidefaces (22) of the friction block (12').

10. A dispenser as in at least one of the Claims 1 to 6, characterized in that at least one catch member (12") is constructed as a springy projection (14) which stands out from the piston (6) to project inwards into the recess (11) and is curved against the discharge direction (25) and which rests springily against the surface of the rod (8) in such a way that upon movement of the rod (8) in the discharge direction (25) an operative connection by frictional engagement may be produced between the projection (14) and the rod (8).

11. A dispenser as in at least one of the Claims 1 to 5, characterized in that the coupling device (5) is constructed as a positive ratchet mechanism (20).

12. A dispenser as in Claim 1, characterized in that the positive ratchet mechanism (20) consists of at least one springy tongue (29).

13. A dispenser as in Claim 12, characterized in that the at least one tongue (29) is attached by one end (30) of it permanently to the piston (6), and rests against the rod (8) by an edge (32) which extends transversely to the longitudinal axis of the rod at the other end (31) of the tongue (29), which is curved against the discharge direction (25).

14. A dispenser as in at least one of the Claims 1 to 13, characterized in that the rod (8) exhibits a smooth surface.

15. A dispenser as in at least one of the Claims 1 to 13, characterized in that the rod (8) exhibits on the surface groove-shaped indentations (16) running transversely to the longitudinal axis of the rod.

16. A dispenser as in at least one of the Claims 1 to 13, characterized in that the rod (8) exhibits a roughened surface.

17. A dispenser as in at least one of the Claims 1 to 6 or 11, characterized in that the positive ratchet mechanism (20) exhibits at least one projection (33) constructed in one piece with the piston (6) to project into the recess (11), and that the rod (8) is constructed as a rack (8') having teeth (24) directed in the discharge direction.

18. A dispenser as in Claim 17, characterized in that the projection (33) exhibits a first area (34) turned towards the discharge direction (25) and inclined obliquely to the rod and a second area (35) lying at an angle to the first area (34) and perpendicular to the discharge direction (25).

19. A dispenser as in at least one of the Claims 1 to 6 or 11 or 17 or 18, characterized in that the recess (11) in the piston (6) is constructed in size and shape in such a way that the teeth (24) on the rod (8) and the projection (33) may upon a movement against the discharge direction (25) be brought out of engagement.

20. A dispenser as in at least one of the Claims 1 to 6, characterized in that the coupling device (5) is constructed as a hook ratchet (27).

21. A dispenser as in Claim 20, characterized in that the hook ratchet (27) exhibits at least one hook-shaped projection (36) moulded onto the piston (6) to project into the recess (11) and directed against the discharge direction (25), and that the rod (8) is constructed as a rack (8') having teeth (24) directed in the discharge direction, which upon movement of the rod (8) in the discharge direction come into engagement with the hook-shaped projection (36).

22. A dispenser as in at least one of the Claims 1 to 21, characterized in that the piston (6) on the side of it next the contents of the container exhibits a sealing collar (18) tightly surrounding the rod (8).

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