EP1836100B1 - Tubular ram for a cartridge, used for expressing pasty substances - Google Patents

Abstract

The piston for cartridges of building sealant has a domed top (12) and vertical walls (14). Two peripheral ribs (16, 17) are mounted near the point where these join. The top rib is curved outwards and has slots (54) spaced around it. The lower rib is vertical and encloses a pocket (19) with the upper rib. An independent claim is included for a cartridge fitted with the piston.

Description

The present invention relates to a piston for a cartridge for pressing pasty substances according to the preamble of claim 1 and an annular piston according to the preamble of claim 10. The cylindrical container or the cylindrical chamber may be made of plastic, aluminum or steel, for example.

Cartridges are used for a variety of pasty substances to be ejected. Widely used z. As cartridges for acrylic or silicone, which are used in construction for sealing joints. Such cartridges are filled and sealed in automatic devices. Here, the heated substance is filled via a filling tube through the open end of the cylindrical container of the cartridge in the cylindrical container. Thereafter, the open end of the cylindrical container with a, in particular cup-shaped, piston is closed. The piston is inserted here, with its end wall in front of the device by means of a plunger in the cartridge. However, there are some problems here:

Residual air between the filler and the piston has the consequence that it later or later in the later processing of the filling substance from the then open injection port of the cartridge, the cannula, exiting, whereby the flow of the pasty substance is interrupted in a sprayed joint filling, that is a rapid and continuous joint filling is no longer possible, but after the interruption by air leakage the Cannula must be rescheduled, which not only delays the workflow, but a smooth, complacent course of joint filling difficult. On the other hand, residual air also contains a proportion of water, namely in the form of water vapor. Some substances to be injected, such as. As silicone, react under the influence of moisture, they harden. The larger the enclosed, compressed quantity of residual air, the greater the proportion of the pasty filling substance which hardens within the cartridge and thus becomes unusable. As a result, the residual air must be removed from the cartridge as much as possible.

In the storage and transport state of the filled cartridge, the piston must on the one hand seal well, so that the enclosed substance is prevented from escaping. On the other hand, however, the piston must also be so movable, namely displaceable in the axial direction within the cartridge, so that the subsequent pressing of the pasty substance still acceptable forces sufficient. Consequently, the piston must be displaceable within a certain range of forces after filling of the cartridge.

In addition, pasty substances are known to contain hydrocarbons. By acting on the hydrocarbons, the piston increases more in the circumferential direction than the cartridge. This can lead to a bursting of the container during or after a certain storage.

Furthermore, the piston must not sit too loose when inserting, because then inadmissibly much pasty substance passes out of its wall on the cartridge, which leads not only to loss of material, but from a contamination of the cartridge.

On the other hand, if the piston is too tight, a more or less large quantity of residual air is trapped behind the filled substance when closing the filled cartridge.

Too tight a seat of the piston also means that it can not move sufficiently in the direction of the filled substance, as this subsequently cools and shrinks, the trapped volume is therefore reduced. The consequence of the shrinkage is then that the container bulges. Such deformed cartridges are virtually unsalable, since a potential buyer creates the impression that the cartridge has been filled a long time ago and the pasty substance is at least partially unusable. On the other hand, such a deformation of the cartridge is disadvantageous, since it hinders a displacement of the piston, which is normally circular in cross-section, at a later ejection and can lead to a loss of pasty substance.

In addition, z. B. in the storage of the filled cartridge z. B. result of temperature changes, an increase in the diameter of the container, which is stronger than a caused by the same reason increase in the diameter of the piston. As a result, the sealing effect of the piston decreases and air can penetrate into the container and come into contact with the pasty substance, which can lead to a curing of the pasty substance.

Coaxial cartridges are used for 2-component masses, such as adhesives, sealants, etc. used, the two components are housed separately from each other in coaxial chambers of cylindrical cartridges and are mixed together for common use by a mouthpiece with mixing nozzle for use.

To express the pistons in a simple cartridge and a coaxial cartridge, a Preßstempelorgan (also known as piston setter) a Ausdrückpistole is used.

To solve the above problems is in the German utility model DE 20319464.0 a piston proposed according to the preamble of claim 1, in which at least one of the two circumferential elastic lamella towards the end wall of the piston is directed substantially obliquely outwards and bears against the inner wall of the container with bias and has on its side facing away from the wall of the piston side at least one projection. The known piston already represents an improvement in terms of the smallest possible amount of residual air when inserting a piston into a cartridge and a good axial mobility of the piston used. Nevertheless, in some cases, the amount of residual air is not sufficiently low enough and the axial mobility is not sufficiently good enough.

The invention is therefore based on the object to provide for even smaller amount of residual air when inserting a piston into a cartridge or coaxial cartridge and an annular piston in a coaxial cartridge and at the same time an even better axial mobility of the piston or piston used.

According to the invention, this object is achieved in the generic piston in that the front in the ejection direction lamella of the two slats is substantially arcuate outwardly, further comprising the front slat circumferentially spaced slits and in the Auspreßrichtung rear slat to the end wall of the piston out substantially runs obliquely outwards and forms a pocket with the front lamella.

According to a further aspect, this object is achieved in the generic annular piston characterized in that on the outer side of the radially outer wall of the annular piston in the vicinity of the end wall two circumferential in radial planes outer elastic blades made of plastic and on the inside of the radially inner wall of the annular piston in the vicinity of the end wall two in radial planes encircling inner elastic lamellae are made of plastic, wherein the front in the pressing out of the two lamellae of the two outer lamellae extends substantially arcuate outward, further comprising the front lamella of the two outer lamellae circumferentially spaced slots and the in Auspreßrichtung rear slat of the two outer slats to the end wall of the annular piston out substantially obliquely outwards and with the front slat the two outer slats forms a pocket, and wherein the front in the pressing direction lamella of the two inner slats is substantially arcuate inwardly, further comprising the front slat of the two inner slats circumferentially spaced slots and the rear slat of the two inner slats in Auspreßrichtung extends to the end wall of the annular piston substantially obliquely inwards and forms a pocket with the front lamella of the two inner fins.

According to a particular embodiment of the invention may be provided in the piston, that the front lamella projects radially outwardly beyond the lamella in Auspreßrichtung.

In particular, the front lamella can be designed to rest with prestress against the inner wall of the container or the chamber.

Conveniently, the rear sipe is designed so as not to abut against the inner wall of the container or the chamber prior to the first squeezing of pasty substances from the cartridge.

Alternatively, it can be provided that the rear lamella has on its outer side a peripheral in a radial plane elevation. In particular, it can be provided that the rear slat is designed to abut before the first pressing of pasty substances from the cartridge to the inner wall of the container or the chamber.

Conveniently, the rear blade extends substantially arcuate obliquely outward.

Advantageously, the rear blade has an end whose surface is roughened. The roughened surface facilitates the venting of the piston.

Preferably, the roughness of the surface is about 30 microns.

A further particular embodiment of the invention is characterized in that on the inside of the end wall at least one of them substantially vertically extending web having a first land height and a first web thickness and at least one thereof substantially perpendicularly extending web with a second land height and a second , Web thickness extends, wherein the first and second web heights are at least substantially identical and the first and second web thicknesses are different. If the piston sits plane-parallel at the beginning of extrusion by means of a plunger, deforms the web or deform the webs with the smaller web thickness in building an internal pressure rather than the web or the webs with greater web thickness, whereby the piston receives a tilt, which in turn deforms elliptical in plan view when pressing in the piston, the rear lip, so that a gap or gap to the wall arises / arise through which / can be done a vent. Then, it is not absolutely necessary that the rear fin has an end with a roughened surface.

Conveniently, the front slat on the outside in a radial plane circumferentially spaced webs. By the webs, the rear slat is pushed outwards more.

Conveniently, the webs extend obliquely or transversely to the direction of rotation of the front blade.

According to a particular embodiment of the invention can be provided that the front blade has a rounded end.

Advantageously, the front sipe forms a pocket with the outside of the wall.

Furthermore, it can be provided that the defined by the outside of the wall, at right angles to the longitudinal axis of the piston extending cross-sectional area decreases towards the end wall.

In particular, it may be provided that the cross-sectional area decreases from a first wall section having a first cross-sectional area via a transition section to a second wall section having a second cross-sectional area.

Conveniently, the root portion of the front fin is arranged in the transition portion.

According to a particular embodiment of the invention, the slots are arranged in the root region of the front lamella.

Conveniently, the rear blade extends at an angle α of 0 to 10 degrees to the longitudinal axis of the piston obliquely outward.

More preferably, the angle α is in the range of 0 to 5 degrees. Most preferably, the angle α is 3 degrees.

Conveniently, the root region of the rear lamella is arranged in the region of the transition between the first wall section and the transition section.

Advantageously, the rear lamella has a beveled outwardly to the end wall of the piston outward end.

Conveniently, the outside of the wall of the piston at least one circumferential in a radial plane, away from the end wall obliquely outwardly directed sealing lip.

More preferably, the outer side of the wall of the piston has two sealing lips running around in radial planes and directed obliquely outwards away from the end wall.

Conveniently, a circumferential in a radial plane, outwardly projecting guide rib is provided on the outside of the wall between the two sealing lips. The guide rib (s) serve to prevent deformation and / or tilting of the piston, particularly when using a compressed air gun.

More preferably, the outer side of the wall of the piston has three sealing lips extending in radial planes away from the end wall, wherein between the sealing lips on the outer side of the wall there is provided an outwardly projecting guide rib extending in a radial plane.

In particular, it may be provided that the or each guide rib has a first flank facing the end wall with a first pitch and a second flank facing away from the end wall with a second pitch, wherein the second pitch is greater than the first pitch.

Furthermore, it is possible that the piston has a round cross-section in the region of the front and rear slats.

Alternatively, it is also conceivable that the piston has an oval cross-section in the region of the front and rear slats.

The invention is based on the surprising finding that the residual air can be removed more easily and to a greater extent than before by the special arrangement and design of the two elastic lamellae circulating in radial planes. At the beginning of venting, the residual air can escape through the slots in the front sipe through the bag to the outside. The front blade is used in the stage for stripping z. As silicone from the inner wall of the container in the direction of the slots. The silicone then enters the pocket and fills it gradually from bottom to top, d. H. from the bottom of the bag upwards. As a result, the rear slat is spread outwards and places it against the inner wall of the container. This causes a lock, so that the silicone can not escape to the rear.

The piston and annular piston according to the invention also allows a squeezing with higher pressures or the use of lower wall thicknesses of the cartridges or coaxial cartridges at the same pressures. This results in a weight reduction of up to 30% and a lower environmental impact and lower disposal costs. This provides a price advantage to consumers. Also, the piston or ring piston is at least in a particular embodiment by the slats more flexible, so that the bursting described above is easier to avoid.

Figur 1

eine Draufsicht auf einen Kolben gemäß einer besonderen Ausführungsform der Erfindung von vorne;

Figur 2

eine Längsschnittansicht des Kolbens von Figur 1;

Figur 3

das Detail X von Figur 2;

Figur 4

eine Längsschnittansicht einer Kartusche mit dem Kolben von Figur 2 in zwei verschiedenen Stadien während des Einsetzens des Kolbens;

Figur 5

das Detail X von Figur 4;

Figur 6

eine Draufsicht auf einen Kolben gemäß einer weiteren besonderen Ausführungsform der Erfindung von vorne;

Figur 7

eine Schnittansicht des Kolbens entlang der Linie VII-VII in Figur 6;

Figur 8

eine Draufsicht auf den Kolben von Figur 6 von hinten;

Figur 9

eine Längsschnittansicht einer Kartusche mit einem Kolben in vier verschiedenen Stadien während des Einsetzens des Kolbens nebst Details X, Y, Z, W;

Figur 10

eine Schnittansicht wie Figur 7 eines Kolbens gemäß einer weiteren besonderen Ausführungsform der Erfindung;

Figur 11

eine Schnittansicht des Kolbens von Figur 10 entlang der Linie XI-XI in Figur 10;

Figuren 12a) - i)

Ausgestaltungen von vorderen und hinteren Lamellen von Kolben gemäß besonderen Ausführungsformen der Erfindung;

Figur 13

eine Längsschnittansicht einer Koaxialkartusche mit einem Kolben und einem Ringkolben gemäß einer besonderen Ausführungsform der Erfindung;

Figur 14

eine Längsschnittansicht des Ringkolbens von Figur 13; und

Figur 15

eine Längsschnittansicht des Kolbens von Figur 13.

Further features and advantages of the invention will become apparent from the claims and the following description in which an embodiment with reference to the schematic drawings is explained in detail. Showing:

FIG. 1

a plan view of a piston according to a particular embodiment of the invention from the front;

FIG. 2

a longitudinal sectional view of the piston of FIG. 1 ;

FIG. 3

the detail X of FIG. 2 ;

FIG. 4

a longitudinal sectional view of a cartridge with the piston of FIG. 2 in two different stages during the insertion of the piston;

FIG. 5

the detail X of FIG. 4 ;

FIG. 6

a plan view of a piston according to another particular embodiment of the invention from the front;

FIG. 7

a sectional view of the piston along the line VII-VII in FIG. 6 ;

FIG. 8

a plan view of the piston of FIG. 6 from the back;

FIG. 9

a longitudinal sectional view of a cartridge with a piston in four different stages during the insertion of the piston with Details X, Y, Z, W;

FIG. 10

a sectional view like FIG. 7 a piston according to another particular embodiment of the invention;

FIG. 11

a sectional view of the piston of FIG. 10 along the line XI-XI in FIG. 10 ;

FIGS. 12a) - i)

Embodiments of front and rear lamellae of pistons according to particular embodiments of the invention;

FIG. 13

a longitudinal sectional view of a coaxial cartridge with a piston and an annular piston according to a particular embodiment of the invention;

FIG. 14

a longitudinal sectional view of the annular piston of FIG. 13 ; and

FIG. 15

a longitudinal sectional view of the piston of FIG. 13 ,

The in the FIGS. 1 to 3 individually shown piston 10 is made of plastic, pot-shaped and has an end wall 12 with a central tip 12 a and a closed wall 14. On the outer side 15 of the wall 14 of the piston 10 in the vicinity of the end wall 12, two elastic lamellae 16 and 17 surrounding in radial planes are formed from plastic. The front in the extrusion direction lamella 17 extends substantially arcuately outward and projects beyond the rear in the extrusion direction 16 slat radially outward. The front louver 17 has circumferentially spaced slots 54 extending in the circumferential direction, and the rear lamella 16 extending in the direction of extrusion extends substantially obliquely outwardly toward the end wall 12 of the piston and forms a pocket 19 with the front louver 17.

The front louver 17 has a rounded end 17a (see FIG FIG. 3 ) on. In addition, the front lamella 17 forms a pocket 21 with the outside 15 of the wall 14. The cross-sectional area of the wall 14 decreases from a first wall section 14a having a first cross-sectional area via a transition section 14b to a second wall section 14c having a second cross-sectional area (see FIG FIG. 3 ). The root portion 17b of the front fin 17 is disposed in the transition portion 14b. In the root area 17b are the slots 54 of the front lamella 17th

The rear blade 16 extends at an angle α of 3 degrees to the longitudinal axis of the piston obliquely outward (see FIG. 3 ).

The root portion 16a of the rear sipe 16 is disposed in the region of the transition between the first wall portion 14a and the transition portion 14b (see FIG FIG. 3 ). The rear lamella 16 has an end 16b which is beveled outwardly towards the end wall 12 of the piston 10 (see FIG FIG. 3 ).

The outer side 15 of the wall 14 of the piston has three circumferential in radial planes, away from the end wall 12 obliquely outwardly directed sealing lips 20, 50 and 62, wherein between the sealing lips 20 and 50 and 50 and 62 on the outer side 15 of the wall 14 respectively a circumferential in a radial plane, outwardly projecting guide rib 25 and 27 is provided (see FIG. 2 ). Each guide rib 25 and 27 has a first flank 25a or 27a facing the end wall 12 with a first pitch and a second flank 25b or 27b facing away from the end wall 12 with a second pitch, wherein the second pitch is greater than the first pitch ,

As it turned out FIG. 1 shows, the piston 10 in the region of the front and rear slats 16 and 17 has a round cross-section.

Next will be on the FIGS. 4 and 5 Referenced. When inserting the piston 10 by pushing into the open end 28 of the cylindrical container 30, which is closed at its end opposite the open end 28 with a bottom (not marked) with a mouthpiece (not marked) for dispensing pasty substances, the cartridge the front lamella 17 applies under bias to the inner wall 32 of the container 30, since the outer diameter resulting from the front lamella 17 is greater than the inner diameter of the container 30, while of course the outer diameter of the wall 14 is less than the inner diameter of the container 30th is. At this stage, however, the rear blade 16 is not on the inner wall 32 of the Container 30, since the outer diameter resulting from the rear blade 16 is smaller than the inner diameter of the container. This leads at this stage to a gap 31 between the rear sipe 16 and the wall 14 (see FIG. 4 below).

As is clear from the FIG. 4 results from the pushing of the piston 10 in the open end 28 into an overpressure, which causes residual air to escape through the slots 54 in the front lamella 17 into the pocket 19 and subsequently around the end 16b through the gap 31 can (see FIG. 4 below). The front louver 17 strips the material 40 from the inner wall 32 and directs it through the slots 54 into the pocket 19. The pocket 19 fills gradually from bottom to top, whereby the rear lamella 16 is pushed outward / spread and to abut comes to the inner wall 32. This prevents the material from getting past the rear sipe 16. As it were, there is a locking towards the rear (see the upper piston in FIG. 4 and FIG. 5 ). In summary, it is achieved by the arrangement and design of the front plate 17 and rear plate 16 that first the residual air is discharged and then the escape of material 40 is prevented to the rear.

In the case of particularly high pressures, the front lamella 17 is even pressed against the rear lamella 16, at least in this embodiment.

In the detail X of FIG. 4 and FIG. 5 the residual air has already escaped and some of the pasty substance 40 has entered through the slots 54 into the pocket 19, whereby the rear lamella 16 is pressed outwards and seals against the inside wall 32 of the container. In the present case, this follows selectively on average.

The in the FIGS. 6 to 8 shown piston 10 is exactly like that in the FIGS. 1 to 5 made of plastic, pot-shaped and has an end face 12 with a central tip 12a and a closed wall 14. In addition, are also on the outside 15 of the wall 14 of the piston 10 in the vicinity of the end wall 12th two elastic disks 16 and 17 encircling radial planes are formed from plastic. The front in the extrusion direction lamella 17 extends substantially arcuately obliquely outwards, but at least not yet inserted into a cartridge state does not protrude beyond the in the pressing direction rear blade 16 radially outward. The rear slat 16 in Auspreßrichtung is rather on the front in the extrusion direction lamella 17 radially outward. The front lamella 17 has circumferentially spaced slots 54 which extend in the circumferential direction, and the rear lamella 16 extends substantially arcuately obliquely outwardly towards the end wall 12 of the piston and forms a pocket 19 with the front lamella 17.

The front louver 17 has a rounded end 17a (see FIG FIG. 9 ) on. In addition, the front lamella 17 forms a pocket 21 with the outside 15 of the wall 14. The cross-sectional area of the wall 14 decreases from a first wall section 14a having a first cross-sectional area via a transition section 14b to a second wall section 14c having a second cross-sectional area (see FIG FIG. 9 ). The root portion 17b of the front fin 17 is disposed in the transition portion 14b (see FIG FIG. 9 ). In the root area 17b are the slots 54 of the front lamella 17 (see FIG. 9 ). Starting from the root region 17b to the end 17a, the front lamella 17 has a substantially constant thickness.

The root portion 16a of the rear sipe 16 is disposed in the region of the transition between the first wall portion 14a and the transition portion 14b (see FIG FIG. 9 ). The rear lamella 16 has an end 16b which is beveled outwardly towards the end wall 12 of the piston 10 (see FIG FIG. 9 ). The surface of the end 16b is roughened, wherein the roughness is about 30μm. Furthermore, on the outside of the rear lamella 16, a circumferential elevation 16c is provided in a radial plane (see FIG FIG. 9 ). Starting from the root region 16a of the rear lamella 16 in the direction of the end 16b, the thickness of the rear lamella 16 in the region of the elevation 16c thus increases and then decreases again due to a weakening 16d, it becomes even smaller than the thickness in the root region 16a and then increases again approximately to the thickness in the root region 16a.

On the inside of the end wall 12 inner reinforcing ribs 22 are molded. Furthermore, two webs 23 with a first web height h ₁ and a first web thickness d ₁ , which extend concentrically to the inner reinforcing ribs 22, are arranged on the inside of the end wall 12. On the side facing radially to the two webs 24 are provided with a second web height h ₂ and a second web thickness d ₂ , which also extend concentrically to the inner reinforcing ribs 22. The first web height h ₁ and the second web height h ₂ are identical and selected such that the webs 23 and 24 protrude from the inside of the end wall 12 to the rear beyond the inner reinforcing ribs. However, the second web thickness d ₂ is selected to be smaller than the first web thickness d ₁ . If thus by means of a plunger from the open side 28 is acted on the piston 12 in a straight line, from a certain pressure, the webs 24 yield due to the smaller web thickness d ₂ , that bend or buckle, so that the piston 12 in the Pressure sets obliquely to the plunger. As already described above, this leads to a better venting of the cartridge.

FIG. 9 shows different stages when using one with the in the FIGS. 6 to 8 shown piston substantially identical piston 10 in a cartridge. The cartridge has a cylindrical container 30 with an open end 28 and a bottom 34 with a mouthpiece 36 shown closed.

When inserting the piston 10 by pushing into the open end 28 of the cylindrical container 30 of the cartridge, the front lamella 17 contacts the inner wall 32. The rear lamella 16 is biased against the inner wall 32 (see detail X). In the detail Y, the rear sipe 16 is pressed inward, wherein between the annular protrusion 16 c and the inner wall 32, a gap 33 is generated.

In detail W, the piston 10 is set and generates an internal pressure. As a result, the rear lamella 16 yields in the area of the constriction 16d, so that the elevation 16c abuts against the inner wall 32 of the container 30 and seals.

Detail Z shows an extreme situation when pressing out, in which the front lamella 17 and the rear lamella 16 bend outward. In this extreme situation, the front lamella 17 can lean on the rear lamella 16 and locks the piston 10 at least almost 100% and thus leaves no pasty substance, such as silicone, back out.

The rear blade 16 has in the sealing area (see detail X) such a selected rough surface that the air can flow out to the rear when setting the piston. This makes it possible to set the piston plane-parallel. The in FIG. 9 shown piston 10 therefore has in deviation from that in the FIGS. 6 to 8 piston shown no webs 23 and 24. In principle, these are only necessary if the end 16b of the rear lamella 16 has no roughened surface.

The in the Figures 10 and 11 shown piston 10 differs from that in the FIG. 9 shown piston 10 in that the front lamella 17 on the outside in a radial plane circumferentially arranged at a constant distance webs 60 has. The webs 60 extend at right angles to the direction of rotation of the front blade 17. The webs 60 are designed so that they rest against the inner wall of the rear blade 16 when setting the piston. Thereby, the rear sipe 16 is pressed more outward against the inner wall 32 of the container 30. This in turn provides a better stripping behavior, especially when using a pure air gun.

FIGS. 12a) to 12i) show exemplary embodiments, arrangements and combinations of front fins 17 and rear fins 16 of a piston or Ring piston according to the present invention, wherein the in FIG. 12a ) embodiment shown in the FIGS. 6 to 8 shown embodiment corresponds.

As is clear from the FIGS. 12a) to 12i) results in the front plate 17 may extend in cross section, for example, also rectilinear and the rear blade 16, for example, also rectilinear and in particular at least almost in the extrusion direction.

FIG. 13 shows a coaxial cartridge 100 for pressing pasty substances according to a particular embodiment of the present invention comprising a cylindrical container 130 made of plastic, which is closed at its one end with a bottom 134 and open at its other end 128 and an inner, in cross-section circular chamber 160 and an outer, annular cross-section chamber 162 which surrounds the inner chamber concentrically. In the chamber 160 is a piston 110 which is in FIG. 15 is shown and apart from the shape of the front wall very much similar to that in FIG. 9 Therefore, the other components have the same reference numerals and reference is made to the relevant description above. In the annular chamber 162 is an annular piston 170, as in FIG. 14 is shown. The annular piston 170 is elastic and made of plastic and in the outer, annular chamber 162 slidably disposed with a radially outer cylindrical wall 172, a radially inner cylindrical wall 174 and a connecting these two end wall 176 at the front end of the annular piston. On the outer side 178 of the radially outer wall 172 of the annular piston 170 are in the vicinity of the end wall 176 two circumferential in radial planes outer elastic plates 180 and 182 formed of plastic and on the inside of the radially inner wall 174 of the annular piston 170 are in the vicinity of the end wall 176 two circumferential in radial planes inner elastic lamellae 186 and 188 made of plastic. The front in squeezing direction lamella 182 of the two outer fins 180 and 182 is like the lamella 17 of FIG. 7 formed and arranged and has slots 183. The in the pressing direction rear slat 180 of the two outer slats 180 and 182 is like the slat 16 of FIG. 7 trained and arranged. Reference is therefore made in this respect to the above description.

The leading in Auspreßrichtung lamella 188 of the two inner plates 186 and 188 extends substantially arcuately inwardly and has circumferentially spaced slots 183 on. The squeezing out in the rear plate 186 of the two inner plates 186 and 188 extends to the end wall 176 of the annular piston 170 in substantially obliquely inward and forms with the front plate 188 of the two inner plates 186 and 188 a pocket 190. The rear plate 186 of the two inner sipes 186 and 188 project radially inwardly beyond the front sipe 188. Furthermore, the rear lamella 186 on its outer side a circumferential in a radial plane elevation 192 and further to the end of a constriction 194 on.

The outer blades 180 and 182 and the inner blades 186 and 180 cooperate with the respective adjacent walls 162a and 162b of the annular chamber 162, as shown in FIGS FIG. 9 shown and described above in the description.

Claims (10)

1. Ram (10; 110) for a cartridge used for expressing pasty substances (40), the cartridge having an approximately cylindrical container (30) or an approximately cylindrical chamber (160) which is closed at its one end by a bottom (34; 134) and is open at its other end (28; 128), wherein the ram (10; 110) is elastic and is made of plastic, and can be arranged in a slidable manner in the container (30) or the chamber (160) with an end wall (12) which faces the bottom of the container (30) or the chamber (160) and a closed wall (14), wherein two elastic blades (16; 17) which encircle in radial planes and are made of plastic are formed on the outside (15) of the wall (14) of the ram (10) in the vicinity of the end wall (12), characterized in that that blade (17) of the two blades (16; 17) which is in front in the expressing direction runs outwards in an essentially curved manner, and, furthermore, the front blade (17) has slots (54) which are spaced apart in an encircling manner, and that blade (16) which is at the rear in the expressing direction runs essentially obliquely outwards towards the end wall (12) of the ram (10 ; 110) and forms a pocket (19) together with the front blade (17).
2. Ram (10; 110) according to Claim 1, characterized in that the front blade (17) protrudes radially outwards over that blade (16) which is at the rear in the expressing direction.
3. Ram (10; 110) according to Claim 1 or 2, characterized in that the front blade (17) is designed so as to bear under prestress against the inner wall (32) of the container (30) or of the chamber (160).
4. Ram (10; 110) according to one of Claims 1 to 3, characterized in that the rear blade (16) is configured so as not to bear against the inner wall (32) of the container (30) or of the chamber (160) prior to the first expression of pasty substances from the cartridge.
5. Ram (10; 110) according to one of Claims 1 to 3, characterized in that the outside of the rear blade (16) has an elevation (16c) encircling in a radial plane.
6. Ram (10; 110) according to Claim 5, characterized in that the rear blade (16) is configured so as to bear against the inner wall (32) of the container (30) or of the chamber (160) prior to the first expression of pasty substances from the cartridge.
7. Ram (10; 110) according to one of the preceding claims, characterized in that the rear blade (16) runs obliquely outwards in an essentially curved manner.
8. Ram (10; 110) according to one of the preceding claims, characterized in that the rear blade (16) has an end (16b), the surface of which is roughened.
9. Ram (10; 110) according to one of the preceding claims, characterized in that the slots (54) are arranged in the root region (17b) of the front blade (17).
10. Tubular ram (170) for a coaxial cartridge (100) used for expressing pasty substances, the coaxial cartridge having an approximately cylindrical container (130) which is closed at its one end (128) by a bottom (134) and is open at its other end (128), and also has an inner chamber (160) which is circular in cross section and an outer chamber (162) which is circular-ring-shaped in cross section and concentrically surrounds the inner chamber (160), wherein the tubular ram (170) is elastic and is made from plastic, and can be arranged in a slidable manner in the outer, circular-ring-shaped chamber (162) with a radially outer, approximately cylindrical wall (172), a radially inner, approximately cylindrical wall (174) and an end wall (176), which connects said two walls, at the front end of the tubular ram (170), characterized in that two outer, elastic blades (180, 182) which encircle in radial planes and are made from plastic are formed on the outside (178) of the radially outer wall (172) of the tubular ram (170) in the vicinity of the end wall (176), and two inner, elastic blades (186, 188) which encircle in radial planes and are made from plastic are formed on the inside of the radially inner wall (174) of the tubular ram (170) in the vicinity of the end wall (176), with that blade (182) of the two outer blades (180, 182) which is in front in the expressing direction running outwards in an essentially curved manner, and, furthermore, the front blade (182) of the two outer blades (180, 182) having slots (183) which are spaced apart in an encircling manner, and that blade (180) of the two outer blades (180, 182) which is at the rear in the expressing direction running essentially obliquely outwards towards the end wall (176) of the tubular ram (170) and forming a pocket (190) together with the front blade (182) of the two outer blades (180, 182), and with that blade (188) of the two inner blades (186, 188) which is in front in the expressing direction running inwards in an essentially curved manner, and, furthermore, the front blade (188) of the two inner blades (186, 188) having slots (183) which are spaced apart in an encircling manner, and that blade (186) of the two inner blades (186, 188) which is at the rear in the expressing direction running essentially obliquely inwards towards the end wall (176) of the tubular ram (170) and forming a pocket (190) together with the front blade (188) of the two inner blades (186, 188).

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