EP2428282A1 - Cartridge piston - Google Patents

Abstract

The piston i.e. ring piston (51), has a piston mantel including a sealing element for forming fluid-tight connection between the sealing element and an inner wall of a storing chamber of a cartridge. The sealing element forms fluid-tight connection between a delivery side (53) and a drive side of a piston body in assembling condition. The piston body includes two ventilation elements (60, 61) through which the conveying and drive sides are connected with each other through a bore hole. A conveying side of the piston body is formed with ventilation slots (71, 73).

Description

The invention relates to a piston for a cartridge, in particular for the discharge of solids-containing filling compounds, which contains a venting device. The fillers may contain multicomponent mixtures. These fillers are introduced into a storage chamber of the cartridge. Subsequently, the filled with the filling material cartridge is closed by the piston. Any air between the piston and the filling compound should escape through the ventilation device.

Such a piston is for example from the DE 200 10 417 U1 known. The piston has a first piston part, which is provided with a sealing lip. The sealing lip abuts the cartridge wall. The piston further has a valve element, which is designed as a second piston part. This valve element has a circular cylindrical wall part, which is located in a recess of the first piston part and is latched at the bottom of this recess with the first piston part by a latching connection. The circular cylindrical wall part is arcuate in a valve pin over. The valve pin penetrates a cylindrical bore on the first piston part and has a valve cone which is intended to bear against a valve lip of the first piston part. The latching connection is interrupted by a small air channel, whereby a filter section is formed between the wall of the first piston part and the inside of the circular-cylindrical wall part of the valve element. Other variants of such an air duct are from the EP 0351 517 A1 , of the EP1738834 A1 or the US2005 / 0029306 A1 known.

Since a piston according to the DE 200 10 417 U1 , of the EP 0351 517 A1 , of the EP1738834 A1 or the US2005 / 0029306 A1 relatively expensive to produce is, various simplifications of this design have been proposed. For example, there are pistons, which instead of a vent valve contain a bore through which air can escape.

However, these prior art pistons have proven unsuitable for the discharge of fillers for subsequent reasons. On the one hand there is a conflict of objectives between the size of the bore and the setting speed of these pistons. For example, in the EP 1 338 342 A1 shown two small holes through which a connection between the delivery side and the drive side is achieved. The diameter of the holes must be so small that a passage of filling material from the delivery side to the drive side can be prevented, the holes must therefore as in the DE 200 10 417 U1 form a filter section. Accordingly, the holes are referred to as capillary channels. This means that capillary forces prevent filling material from getting through the holes to the drive side of the piston. Therefore, the setting speed for this piston is small because it must be ensured during the setting of the piston that the filling material located between the piston and the air can be discharged through the holes.

The larger the bore, the faster the air can escape from the space between the piston and the filler when the piston is inserted into the reservoir. However, a larger bore results in a larger volume of fill mass being able to pass through this bore and increases the risk of contamination of the bore on the drive side of the piston.

By the term setting the piston is meant the installation of the piston in the storage chamber of the cartridge. The filled with filling material storage chamber of the cartridge is sealed fluid-tight by the piston. For this purpose, the piston is placed on the inlet opening of the cartridge and pushed a piece into this storage chamber, usually to the extent that the drive side of the piston is flush with the inlet opening, so no part of the piston protrudes beyond the inlet opening.

Another problem arises when setting the piston especially for viscous or pasty fillers. Such a viscous or pasty filling material has no defined level in the storage chamber, as is known for a liquid which forms a meniscus. The surface of such a viscous or pasty filling material is not flat, but has mountains and valleys. Therefore, the level may be locally much higher than would be expected according to the mean value. The setting process of the piston, however, is usually controlled by path, that is, the piston is moved along a preset path in the storage chamber of the cartridge. This means that the piston can come into contact with the mountains of the filling compound before the piston has reached its end position. When a mountain strikes the vent, it becomes clogged and an air bubble can remain between the filler and the delivery side of the piston. If the setting process continues, this bubble is compressed.

Even if the filling material does not escape directly through the bore on the drive side of the piston during the setting process, the filler mass may subsequently enter the bore due to a slow degradation of the internal pressure increased by the setting process. Although this hole is closed in a subsequent operation, for example, welded. However, when filling material is in the bore, the welding process may be impaired or the welding may be incomplete so that filling material can escape through the bore to the drive side of the piston. This means that there is a leak, which can cause the shelf life of the filling material is no longer guaranteed.

The object of the invention is to provide an improvement to the said piston, so that the piston filling masses can be sealed fluid-tight in a storage chamber of a cartridge, so that the filling material in the cartridge is storable at least for a limited period. The piston should be displaceable by means of commercial dispensing devices in the storage chamber of the cartridge.

This object is achieved by a piston for a cartridge, wherein the cartridge contains at least one storage chamber for storing a filling material. The piston comprises a piston body which has a delivery side and a drive side opposite the delivery side and a piston skirt. The piston skirt is arranged around a piston axis and the piston body is circumferentially surrounded by the piston skirt. The piston skirt has a sealing element for forming a fluid-tight connection between the sealing element of the piston skirt and an inner wall of the reservoir chamber of the cartridge, so that the sealing element, when installed, forms a fluid-tight connection between the delivery side and the drive side. The piston body includes a first and a second vent element, through which the delivery side and the drive side of the piston can be connected to each other by a respective bore and the piston body has a vent slot, which is arranged on the delivery side. At least one of the bores may in particular have a circular cross-section. The holes extend through the piston body, they are thus inside the piston body, that is, the holes are not arranged on an inner or outer edge of the piston body.

The provision of a first and second bore has the advantage that the vent is still guaranteed, even if a hole is clogged by an irregular surface of the filling compound during the setting process. In addition, the setting speed of the piston can be increased if a second bore is provided, since the throughput of air is increased when both holes are free of filling material.

For at least one of the first and second venting elements, a first inlet opening and a second inlet opening are preferably provided, which open into the bore. For this purpose, a first and second connecting channel may be provided. The connecting channel and / or the bore extends from the drive side to the delivery side of the piston. In particular, the first and second connecting channel may open into a common collecting channel, wherein the collecting channel may be the bore. Alternatively, to everyone Inlet port include its own bore, which connects the delivery side with the drive side.

The piston body has a vent slot, which is arranged on the delivery side. Through the vent slot, the formation of gas bubbles, which are enclosed by the delivery-side piston surface and the filling compound can be avoided. The vent slot in any case provides a possibility for gas to be directed to the inlet port of the venting element. In particular, the vent slot communicates with the first and second inlet ports.

At least one of the bores has a longitudinal axis, which is aligned substantially parallel to the longitudinal axis of the piston. This variant is particularly easy to produce.

At least one of the inlet openings may be aligned at an angle to the longitudinal axis of the venting element. In particular, the longitudinal axis of the inlet opening is arranged at an angle to the longitudinal axis of the bore of the venting element. If filling material should reach such an inlet opening, this inlet opening will not be clogged immediately.

The angle in this case is greater than 10 ° to and including 90 °, preferably greater than 20 ° to and including 90 °, more preferably greater than or equal to 30 ° to and including 90 °.

Furthermore, bore may contain at least one kink, a bend or a throttle element. As a result, the distance for an entering into the bore filling material is extended. The bends, kinks or throttle points form flow obstacles, by which it is prevented that filling material can reach the drive side of the piston.

Preferably, the minimum diameter of the bore is greater than 1/40 of the diameter of the piston.

A piston according to one of the preceding embodiments may be formed as an annular piston. Such a piston comprises an inner piston skirt, wherein the inner piston skirt defines the piston body on an inner side facing the piston axis, comprising an inner sealing element for producing a sealing contact with a wall of an inner tube arranged inside the inner piston skirt.

The piston can be configured such that a protective element is attached to the piston body on the delivery side. Such a protective element may be made of a material having a higher resistance to filling than the piston material. Thus, the protective element can develop a protective function for the piston material.

The protective element may include a venting element. This venting element is used to remove gases from gas inclusions, which arise, for example, when setting the piston described above, from the piston interior. In particular, the gas may be air.

On the drive side of the piston stiffening ribs may be arranged. The provision of stiffening ribs ensures that the piston remains dimensionally stable, even when the discharge of the filling of the piston is placed under pressure by means of a discharge device.

On the drive side of the piston, a Kippsicherungselement may be arranged, which serves to improve the guidance of the piston in a cartridge. The piston is guided non-tilting by the anti-tip element, which is in contact with the wall of the cartridge, that is, the axis of the piston body coincides with the piston axis. By the anti-tip element is ensured that the delivery side is arranged in a plane normal to the piston axis, or if the delivery side is not flat, that points of the delivery side piston surface, which are characterized by a certain radius and a certain height, along the circumference in substantially the same Normal level lie. If the piston tilted, the condition for such points would not be met. By such Kippsicherungselement can a circumferential Can be maintained contact with the wall of the cartridge during the entire discharge process, so that together with the guide element described earlier, a deflection of the piston can be prevented.

The advantages of the particular features which the ring piston may have correspond to the advantages as mentioned in connection with a piston for a cylindrical interior or an interior of another geometric shape without internals in the earlier place.

A discharge device comprises a piston according to one of the preceding embodiments. The discharge device comprises in particular a cartridge for discharging a plurality of components, wherein the components are arranged in juxtaposed or coaxially arranged storage chambers of the cartridge. Furthermore, the discharge device may comprise a discharge device, by means of which the piston is connectable on the drive side.

Particularly advantageous is the piston according to one of the preceding embodiments use for the discharge of solids-containing fillers, as well as pasty or viscous filling materials such as sealants or adhesives.

Fig. 1

eine Austragvorrichtung enthaltend je einen Kolben in einer mit Füllmasse befüllten Vorratskammer

Fig. 2a

einen Schnitt durch einen Kolben gemäss eines ersten Ausführungsbeispiels nach dem Stand der Technik

Fig. 2b

einen Schnitt durch eine Kolbenhälfte gemäss eines zweiten Ausführungsbeispiels nach dem Stand der Technik

Fig. 2c

ein Schnitt durch einen Kolben nach Fig. 2b in perspektivischer Darstellung

Fig. 3

eine Darstellung einer Koaxialkartusche

Fig. 4

eine Ansicht auf die Förderseite eines Kolbens gemäss eines ersten Ausführungsbeispiels der Erfindung

Fig. 5

eine Ansicht auf die Antriebsseite des Kolbens gemäss Fig. 4

Fig. 6a

einen Schnitt durch eine Kolbenhälfte des Kolbens gemäss Fig. 4 in einer vereinfachten Ausführung

Fig. 6b

einen Schnitt durch eine Kolbenhälfte des Kolbens gemäss Fig. 4

Fig. 7

einen Schnitt durch eine Kolbenhälfte eines Kolbens gemäss eines zweiten Ausführungsbeispiels der Erfindung

Fig. 8

einen Schnitt durch eine Kolbenhälfte eines Kolbens eines dritten Ausführungsbeispiels der Erfindung

Fig. 9

einen Schnitt durch eine Kolbenhälfte eines Kolbens eines vierten Ausführungsbeispiels der Erfindung

Fig. 10

einen Schnitt durch eine Kolbenhälfte eines Kolbens eines fünften Ausführungsbeispiels der Erfindung

The invention will be explained with reference to the drawings. Show it:

Fig. 1

a discharge device containing a respective piston in a filled with filling material pantry

Fig. 2a

a section through a piston according to a first embodiment of the prior art

Fig. 2b

a section through a piston half according to a second embodiment of the prior art

Fig. 2c

a section through a piston after Fig. 2b in perspective view

Fig. 3

a representation of a coaxial cartridge

Fig. 4

a view of the delivery side of a piston according to a first embodiment of the invention

Fig. 5

a view on the drive side of the piston according to Fig. 4

Fig. 6a

a section through a piston half of the piston according to Fig. 4 in a simplified version

Fig. 6b

a section through a piston half of the piston according to Fig. 4

Fig. 7

a section through a piston half of a piston according to a second embodiment of the invention

Fig. 8

a section through a piston half of a piston of a third embodiment of the invention

Fig. 9

a section through a piston half of a piston of a fourth embodiment of the invention

Fig. 10

a section through a piston half of a piston of a fifth embodiment of the invention

Fig. 1 shows a discharge device comprising a cartridge 17 for discharging a plurality of components and a static mixer 20 which is mounted and held on the outlet of the cartridge.

The static mixer 20 includes a mixer housing 21 in which an array of mixing elements 22 is located. The mixer housing 21 includes at its first end 23 two separate inlet openings 25, 26, which are designed as nozzles, which can be plugged into corresponding outlet openings 44, 45 of the cartridge or inserted into this. The second end 24 of Mixer housing 21 includes an outlet opening 27 through which the mixture can escape to be supplied to the desired application can. The mixer housing 21 and the arrangement of mixing elements 22 can be designed as two separate components, which are optionally movable relative to each other.

The mixer housing 21 is connected by a holding element 40 to the outlet element 46 of the cartridge, wherein the connection can be designed as a screw connection or as a bayonet connection, such as in the EP0730913 A1 is executed. According to the embodiment according to Fig. 1 engage a first and a second fastening element 41, 42, which is arranged on the holding element 40, in corresponding first and second receiving elements 47, 48 of the outlet element 46 a. The holding member 40 is rotatable relative to the outlet member 46, wherein a rotary member 49 may be provided, by means of which the holding member 40 is rotatable relative to the outlet member 46 and the first end 23 of the mixer and the fastening elements 41, 42 with the corresponding receiving elements 47, 48th can be brought into engagement.

The cartridge 17 is designed as a multi-component cartridge, wherein the components are arranged in juxtaposed or coaxially arranged cavities of the cartridge. These cavities are to be referred to below as storage chambers for the filling material. The storage chambers can be closed by pistons 50, 51, and the outlet openings 44, 45 of the outlet element 46 can be closed by a cap, not shown, or by a static mixer, which is already blocked by hardened mixture.

The pistons 50, 51 are movable along the wall 16 of the corresponding storage chamber. The pistons are introduced through inlet openings 10, 11 into the storage chambers. The process of inserting the pistons in the filled with filling material pantries is referred to as setting the piston.

Of course, the invention is equally applicable to pistons for one-component cartridges and coaxial cartridges.

Fig. 2a shows a piston, as it is known from the prior art DE 200 10 417 U1 is known. The piston 101 comprises a piston body 102, which is usually made of plastic by means of an injection molding process. The piston 101 is preferably used to discharge a filling material, in particular of fluid or pasty media, out of a cartridge. A wall 116 of the cartridge 117 is shown. The piston 101 slides along the wall 116 and during this movement pushes the filling through an outlet opening, not shown, of the cartridge. The media-side side of the piston 101 will be referred to below as the delivery side 103. In order to set the piston in motion and to keep moving, a compressive force is applied by means of a discharge device. The discharge device, of which a plunger element 118 is shown, is located on the side of the piston, which lies opposite the delivery side 103. This page is referred to below as the drive side 104.

The piston body 102 is thus limited by the drive side 104, the delivery side 103 and a piston skirt 105. The piston skirt 105 forms the connection between the drive side 104 and delivery side 103. In most cases, the piston body has a plurality of recesses or is constructed as a hollow body. Already for reasons of material savings and because of the difficulties that the injection molding of thick-walled components entails, such pistons are already made from diameters of a few centimeters as thin-walled components. The required dimensional stability of the piston is obtained by stiffening ribs 115. In addition, the piston can contain a protective element 113. A protective element 113 may be formed as a cover, the function of which is to shield the piston body from the filling. A cover is used when the filler tends to attack the piston material. This is especially true for soft plastic pistons such as LDPE. For example, LDPE is attacked by polyester resins and swells up.

The piston may also contain a venting element. Such a venting element 114 is in Fig. 1 shown. By this venting element gas, which is located in the storage chamber of the cartridge 117 between the filling material and the piston 101, to the outside, that is to escape to the drive side 104, without the filling material exiting. The venting element 114 is closed as long as the cartridge is stored in the filled state. That is, the pin 119 of the venting element 114 rests on the corresponding seat 120.

If the filling material is to be discharged, the discharge device 118 is brought into contact with the piston 101 on its drive side 104. In this case, the dispensing device also comes into contact with the end of the pin 119 of the venting element 114. The end of the pin 119 protrudes beyond the surface which comes in contact with the discharge device on the drive side, so that the pin lifts off its seat 120 when the discharge device 118 comes into contact with the drive side 104. In this case, a flow path for the gas is opened. The gas enters the space between the valve body 122 and the piston body 102 via the flanks 121 of the valve body 122 in the form of a cover disk and leaves the piston via the opened flow path through the opening between the pin 119 and the seat 120.

The flanks 121 are engaged via latching connections with the piston body 102. For this purpose, the flank 121 engages, for example, in a circumferential groove 123 of the piston body 102 on the delivery side 103. The flank can also have a sealing lip, which engages in a recess of a projection 106 of the piston 101. For the gas usually several small recesses are provided in the flank. Subsequent to these recesses, a labyrinthine connection path between the piston body 102 and the cover plate 113 may be provided. Thus, filling material passing through the recesses may be deposited along this labyrinthine communication path. This connection is not shown in detail.

The piston 101 has means against the discharge of filling compound on the drive side 104. For this purpose, along the sliding surface on the wall 116th the cartridge usually provided at least one sealing lip. The sealing lip 107 is located on a projection 106 which extends between the groove 123 and the wall 116 of the cartridge. The protrusion 106 is formed as an arm communicating with the piston body 102. This arm belongs to an annular bead which extends along the entire circumference of the piston body 102 and forms a fluid-tight connection with the wall 116 of the cartridge 117.

Fig. 2b shows a section through a piston half of a piston 201 according to a second embodiment of the prior art. A piston half of this piston is also in the Fig. 2c shown. The piston 201 comprises a piston body 202, which is usually made of plastic by means of an injection molding process. The piston 201 is used to discharge a filling material, in particular of fluid or pasty media, out of a cartridge. A wall 216 of the cartridge 217 is shown. The piston 201 slides along the wall 216 and in this movement pushes the filling compound out through an outlet opening, not shown, of the cartridge. In order to move the piston in motion and to keep moving, a compressive force is applied by means of a discharge device, which analogous to the Fig. 2a can be trained.

The piston body 202 is thus limited by the drive side 204, the delivery side 203 and a piston skirt 205. The piston skirt 205 forms the connection between the drive side 204 and delivery side 203. In most cases, the piston body has, as in Fig. 2a a plurality of recesses or is designed as a hollow body. The cut of the Fig. 2b as well as the Fig. 2c is laid by a radially extending stiffening rib 215 of the piston.

The piston includes a venting element 214, which is formed as a bore. By this venting element 214, gas, which is located in the storage chamber of the cartridge 217 between the filling material and the piston 201, to the outside, that is to the drive side 204 escape without the filling material exits when the bore has a sufficiently small diameter. However, a hole with a small diameter results in a correspondingly high pressure loss, so that the Setting speed of the piston is correspondingly low. The radius of the bore is denoted by R1, the piston radius by R2. As the piston radius R2, the distance from the piston axis 209 is selected to the end of the sealing lip 207, which corresponds to the inner radius of the storage chamber of the cartridge. In the present embodiment according to Fig. 2c the ratio of R1 / R2 is 1/45.

Fig. 3 is a representation of a coaxial cartridge 30. In a coaxial cartridge two or more coaxially arranged cylindrical storage chambers 31, 32 are arranged for one component of the filling compound. The inner storage chamber 31 is completely surrounded by the outer storage chamber 32. The outer storage chamber 32 is arranged in a ring around the inner storage chamber 31. The outer boundary of the outer storage chamber is designed as a cylindrical cartridge wall 16. The inner storage chamber 31 is delimited by an inner tube 67. The inner and outer storage chamber each contain a piston 50, 51. The inner piston 50 is located in the inner storage chamber 31, the annular piston 51 in the outer storage chamber 32nd

Furthermore, a discharge device 80 is shown, by means of which the inner piston 50 and the annular piston 51 can be moved simultaneously. The dispensing device includes an annular ram 81 for moving the annular piston 51 and an inner ram 82 for moving the inner piston 50. The inner ram 82 has in this embodiment, an external thread 83, which is in engagement with an internal thread 84, which is part of a attachment element 85 is. This attachment element 85 is placed on the inlet openings 33, 34 of the cartridge and remains fixedly connected to these, as long as the filling material located in the storage chambers 31, 32 is discharged.

The attachment element is fixedly connected to the cartridge. By a rotational movement of the inner plunger 82, this is moved relative to the internal thread 84, so that the inner piston 50 is displaced in the storage chamber 31 in the direction of the outlet element 86 of the cartridge. The outer plunger 81 has a head end 87, which is rotatably mounted on a bearing surface 88 adjoining the external thread 83. A stop 89 prevents a displacement of the outer ram 81 relative to the inner ram 82. The outer ram 81 has a foot end 90 which rests on the annular piston 51. Advantageously, the foot end 90 has an annular bearing surface. Between the head end 87 and the foot end 90 extends a guide element, which is guided through a bore 91 of the attachment element 85. Annular piston 51 and inner piston 50 can thus be moved simultaneously.

Fig. 4 shows a view of the delivery side 53 of a piston according to a first embodiment of the invention, for example, in a coaxial cartridge according to Fig. 3 is used as an annular piston 51. In particular, a first and a second venting element 60, 61 are shown. Since the piston has two or more venting elements, even with the same diameter of the venting element as in the prior art, the volume flow can be doubled. That is, the setting speed of the piston can be increased accordingly. Surprisingly, this does not lead to a passage of filling compound on the drive side of the piston. Each of the venting elements is arranged in a venting slot 71, 73. That is, the filling material must penetrate into the narrow vent slot and reach up to the inlet opening of the venting element. Advantageously, the inlet opening 62, 63 of the venting element is arranged at an angle to the surface of the piston on the delivery side 53.

The vent slot has a function as a throttle element for the filling compound and the function to detect gas inclusions at each point of the associated piston half and to allow the transport of the gas to the corresponding inlet port 62, 63. In particular, when the filling compound is viscous, it forms no defined surface. The surface of the filling material may contain mountains and valleys. If such a mountain happened to hit directly on the inlet opening of the venting element, it could lead to a blockage of the venting element. But meets such a mountain on a vent slot, the gas can flow past the place of impact of the summit of the filling material through the vent slot 71, 73 in the corresponding inlet opening, as it is in Fig. 6b is shown in detail. The arrows 68 designate the flow path of the gas.

Fig. 5 shows a view of the drive side 54 of the piston 51 according to Fig. 4 , The two vent elements 60, 61 are opposite each other in a mirror-symmetrical arrangement with respect to a plane extending vertically through the longitudinal axis 9 of the piston in the drawing plane. They do not lie on the radially and axially extending stiffening ribs 65, but in a space between these stiffening ribs. Everyone in Fig. 4 shown venting slots 71, 73 does not coincide with the stiffening ribs.

Fig. 6a shows a section through a piston half of the piston according to Fig. 4 , The annular piston 51 comprises a piston body 52, which is usually made of plastic by means of an injection molding process. The annular piston 51 is preferably used to discharge a filling material, in particular of fluid or pasty media from a coaxial cartridge, for which a possible design in Fig. 3 is shown. A wall 16 of the cartridge is shown. The annular piston 51 slides along the wall 16 and, in this movement, pushes the filling compound through an outlet element 86 (not shown) Fig. 3 ) arranged outlet opening. The media-side side of the piston 51 will be referred to below as the delivery side 53. In order to set the piston in motion and to keep moving a compressive force is applied by means of a discharge device. The dispenser, which is not shown here, is located on the side of the piston, which is the delivery side 53 opposite. This page is referred to below as the drive side 54.

The piston body 52 is thus bounded by the drive side 54, the delivery side 53 and an outer piston skirt 5 and an inner piston skirt 55. The outer piston skirt 5 may have the same structure as below FIGS. 7 to 10 for a simple piston 1 is described. The inner piston skirt 55 forms the inner connection between the drive side 54 and the delivery side 53. The inner piston skirt 55 delimits the piston body 52 on an inner side 59 facing the piston axis 9.

The inner piston skirt 55 merges into a projection 56 on the delivery side 53. The projection 56 is in the embodiment, a thin-walled rotationally symmetrical body, which is visible in the sectional view as an arm of the piston body 52. The projection 56 has an inner guide element 57 for guiding the piston along an inner tube 67 of the cartridge. The guide member 57 is suitable for making a sealing contact with a wall 66 of the inner tube 67. The guide member 57 may be formed in particular as a sealing lip. If necessary, a plurality of sealing lips may be provided. The projection 56 comprises a stripping element 58, which has a smaller distance to the conveying side 53 than the guide element 57.

The annular piston includes a first and a second venting element 60, 61 wherein the second venting element in Fig. 6a is not shown in the drawing. In its simplest embodiment, the venting element 60 is formed as a bore which extends from the delivery side 53 of the piston to its drive side 54. According to the in Fig. 6a In the illustrated embodiment, the venting element has a longitudinal axis 70 that is substantially parallel to the longitudinal axis 9 of the piston. The venting element 60 has an inlet opening 62 and an outlet opening 72. Gas, in particular air, which has accumulated on the delivery side 53 between the filling compound and the piston surface, can enter the bore through the inlet opening and passes through the bore in the direction of the outlet opening 72 directed. This variant is particularly suitable for filling compounds which form a substantially flat surface.

If two or more vent elements are arranged distributed over the piston body 52, local gas inclusions can be avoided. Even if a venting element clogged prematurely because filling material passes through its inlet opening 62, the gas is still at least one other venting element available.

The piston body has stiffening ribs 65. The venting element may be part of such a stiffening rib, which in Fig. 6a is shown. The outlet port 72 of the venting element is accordingly arranged on a stiffening rib, whereby the position of this outlet opening is precisely defined. If the outlet opening to be closed after completion of the setting process, it can be easily welded. The position of the outlet opening is precisely defined and distortion of the piston can be prevented by the heat during the welding process, since the stiffening rib acts analogous to a fixed clamping for the outlet opening.

In addition, the piston according to Fig. 6a an outer and an inner anti-tilting element 18,64, so that the piston can not tilt, whereby the piston is stabilized in its position relative to the wall 16 of the cartridge.

Fig. 6b shows a section through a piston half of the piston according to Fig. 4 in which the bore for the venting element 60 according to the bore Fig. 6a different. The venting member includes first and second inlet ports 62, 63 in addition to the bore connecting the delivery side 53 to the drive side 54.

This in Fig. 6b shown venting element 60 is located adjacent to the stiffening ribs 65. In Fig. 6b a radially extending stiffening rib is shown, which is arranged outside of the venting element 60. The stiffening rib 65 thus has a greater distance from the piston axis 9 than the longitudinal axis 70 of the venting element. The venting element is formed stub 74, which projects beyond the stiffening ribs on the drive side 54. The greater length of the venting element facilitates accessibility for a welding tool, by means of which the outlet opening 72 is closed after completion of the setting of the piston. The closure is necessary to prevent leakage of filling material when the cartridge is stored in such a way that the piston does not occupy the highest position. In addition, it may be necessary for individual fillers that they do not come into contact with air during storage, because this can lead to chemical reactions that can change the properties of the filling mass undesirably.

In addition, it is advantageous if the neck has the greatest possible length, as this extends the channel formed by the bore. Should filling material actually reach one of the inlet openings, the time duration can be extended until the filling material would reach the outlet opening. It is to be expected that in the case of viscous filling compounds which do not form a defined filling level, but rather a surface consisting of mountains and valleys, it will happen that this filling material penetrates into the ventilation slot and penetrates to the inlet opening 62, 63. Therefore, before the exhaust port is actually reached, the setting process will be completed. Therefore, the outlet port 72 can be welded without fear of contamination of the same with filling material. Namely, if the filling material is viscous, the flow rate of the same even at a possibly following the setting process pressure equalization is so low that the operation of welding is already completed before filling material could escape through the outlet opening. Thus, by the in Fig. 6b shown embodiment, a contamination of the outlet opening can be avoided. Consequently, the outlet opening can be welded fluid-tight, so that the filled cartridge can be stored for long periods in any position.

Fig. 7 shows a piston 1, which for a one-component cartridge, as an inner piston 50 for a coaxial cartridge or as one of the pistons 50, 51 of a two-component cartridge with adjacent pantries, as in Fig. 1 shown, can be used. The piston 1 comprises a piston body 2, which is usually made of plastic by means of an injection molding process.

A wall 16 of the cartridge 17 is shown. The annular piston 1 slides along the wall 16 and pushes in this movement, the filling material through a not shown, arranged in the outlet member 46 outlet opening 44, 45 (see Fig. 1 ) or one in the outlet member 86 (see Fig. 3 ) arranged outlet opening. The media-side side of the piston 1 will be referred to below as the delivery side 3. In order to set the piston in motion and to keep moving a compressive force is applied by means of a discharge device. The dispenser, which is not here is shown located on the side of the piston, which is the delivery side 3 opposite. This page is referred to below as the drive side 4.

The piston body 2 is thus limited by the drive side 4, the delivery side 3 and a piston skirt 5. The piston skirt 5 can have the same structure as the outer piston skirt of the Fig. 6 to 6b ,

The piston skirt 5 merges into a projection 6 on the delivery side 3. The projection 6 is a thin-walled rotationally symmetrical body in the embodiment, which is visible in the sectional view as an arm of the piston body 2. The projection 6 has an inner guide member 7 for guiding the piston along the wall 16 of the cartridge. The guide member 7 is suitable for making a sealing contact with a wall 16 of the storage chamber of the cartridge 17. The guide element 7 may be formed in particular as a sealing lip. If necessary, a plurality of sealing lips may be provided. The projection 6 comprises a stripping element 8, which has a smaller distance from the conveying side 3 than the guide element 7.

The piston 1 includes a first and a second venting element 60, 61 wherein the second venting element in Fig. 7 is not shown in the drawing. The venting element 60 has a longitudinal axis 70 which is substantially parallel to the longitudinal axis 9 of the piston. Through an inlet opening 62, gas, in particular air, which has accumulated on the delivery side 3 between the filling compound and the piston surface, enter into a bore 75 and is passed through the bore 75 in the direction of the outlet opening 72.

Through the bore 75, a connection between the delivery side 3 of the piston and its drive side 4 is formed. The diameter of the bore may vary, for example, the diameter may decrease in increasing distance to the delivery side. According to Fig. 7 the diameter profile is conical. At the narrowest point, the bore 75 forms a throttle element 69. If filling material should reach up to the throttle element, this represents an obstacle to the filling compound, so that the discharge of filling compound on the drive side 4 of the piston at least as is long delayed until the delivery end of the bore whose outlet opening 72 has been closed in a subsequent step, for example by a plug or welded.

Subsequent to the throttle element 69, the bore of the venting element can expand again, so that any filling material passing through the throttling element can be deposited in the bore and prevents the filling compound from reaching the vicinity of the outlet opening 72.

The venting element has a nozzle 74. The nozzle 74 has substantially the same length as the stiffening rib 15, so that the nozzle 74 can serve as a support for a discharge device 80,

If two or more vent elements are arranged distributed over the piston body 2, local gas inclusions can be avoided. Even if a venting element clogged prematurely, because filling material passes through its inlet opening 62, the gas is still at least one other venting element available, so that gas inclusion between the filling compound and the delivery side of the piston is avoided.

In Figure 8 a piston 1 is shown with a variant of the venting element 60, which substantially corresponds to the venting element, which in Fig. 4 . Fig. 5 and Fig. 6b is shown for an annular piston.

The piston 1 comprises a piston body 2 which has a delivery side 3, a drive side 4 opposite the delivery side 3 and a piston skirt 5, wherein the delivery side 3 and the drive side 4 are circumferentially surrounded by the piston skirt 5. The piston 1 is preferably a plastic component, which has been advantageously produced by injection molding. The piston skirt 5 forms a connection between the delivery side 3 and the drive side 4, wherein the piston skirt 5 is arranged around a piston axis 9. In particular, the piston skirt is rotationally symmetrical when the piston is intended to be received in a cylindrical cartridge. The piston skirt 5 goes on the Delivery side 3 in a projection 6 via. The projection 6 is a thin-walled rotationally symmetrical body in the embodiment, which is visible in the sectional view as an arm of the piston body 2. The projection 6 has a guide element 7 for guiding the piston in a cartridge 17, which is suitable for producing a sealing contact with a wall 16 of the cartridge 17. The guide element may be formed in particular as a sealing lip. If necessary, a plurality of sealing lips may be provided.

On the drive side 4 of the piston, a Kippsicherungselement 18 may be arranged, which serves to improve the guidance of the piston in a cartridge. The piston is guided by the anti-tip element 18, which is in contact with the wall 16 of the cartridge 17, non-tilting, that is, the axis of the piston body 2 coincides with the piston axis 9. By the anti-tip element 18 ensures that the delivery side 3 is arranged in a plane normal to the piston axis 9, or if the delivery side 3 is not a flat surface or contains portions that are not in a plane that points the delivery-side piston surface by a certain Radius and a certain height are located along the circumference in substantially the same normal plane. If the piston 1 tilted, the condition for such points would no longer be satisfied. Through such a tilt protection element 18, therefore, a circumferential contact with the wall 16 of the cartridge can be maintained throughout the discharge process, so that a deflection of the piston can be prevented together with the guide element 7 described earlier.

This in Fig. 8 shown venting element 60 is located adjacent to the stiffening ribs 65. A radially extending stiffening rib 65 is disposed at a radius smaller than the radius associated with the venting element 60, that is, the stiffening rib 65 is spaced closer to the piston axis 9 than the longitudinal axis 70 of the venting element. The venting element 60 has a bore 75 which connects the delivery side 3 of the piston with the drive side 4. The gas passes into the bore 75 via two inlet openings 62, 63. The inlet openings are arranged at an angle to the piston surface. The piston surface is in this embodiment, the slot bottom 76 of a vent slot 71, as in Fig. 4 . Fig. 5 or Fig. 6b can be trained. The slot bottom 76 lies in a normal plane to the piston axis 9. The angle 77 between the slot bottom and the inlet plane of the inlet opening is preferably greater than 0 ° and can be up to 90 °.

The venting element has a nozzle 74, which projects beyond the stiffening ribs on the drive side 4. The greater length of the venting element facilitates accessibility for a welding tool, by means of which the outlet opening 72 is closed after completion of the setting of the piston. The closure is necessary to prevent leakage of filling material when the cartridge is stored in such a way that the piston does not occupy the highest position. In addition, individual fillers may require that they not come into contact with air during storage because chemical reactions of the fill mass with the air may occur.

In addition, it is advantageous if the nozzle 74 has the greatest possible length, as this extends the channel formed by the bore. Should filling material actually reach one of the inlet openings 62, 63, the time duration can be extended until the filling material would reach the outlet opening. It is to be expected that it forms at most with viscous filling materials, which do not form a defined filling level, but a surface consisting of mountains and valleys. In addition, this filling material penetrates into the vent slot and can penetrate to the inlet opening 62, 63. Therefore, before the exhaust port is actually reached, the setting process will be completed. Therefore, the outlet port 72 can be welded without fear of contamination of the same with filling material. Namely, if the filling material is viscous, the flow rate of the same even at a possibly following the setting process pressure equalization is so low that the operation of welding is already completed before filling material could escape through the outlet opening. Thus, by the in Fig. 8 shown embodiment, a contamination of the outlet opening can be avoided. As a result, the outlet opening can be fluid-tight be welded, so that the filled cartridge over long periods of time in any position is storable.

Fig. 9 shows a variant of the piston 1 with a traversing the entire piston body 2 venting slot 71. Parts of the piston 1 have the same function as in Fig. 8 bear the same reference numbers. The venting element 60 has labyrinth-like channels 78, 79 which connect the inlet ports 62, 63 to the bore 75. These labyrinthine channels form a filter section in which filling material can be deposited. This avoids that filling material can reach the outlet opening 72.

Fig. 10 shows a variant of a piston 1 for filling materials, which tend to chemically change the plastic of the piston. The piston 1 comprises a piston body 2, which has a delivery side 3, a drive side 4 opposite the delivery side 3, and a piston skirt 5 and a protective element 13. The piston skirt 5 connects delivery side 3 and drive side 4 and constitutes the boundary to the wall 16 of the cartridge 17 ,

The protective element 13 is designed as a cover plate and covers the piston body 2, so that the piston body of the filling compound is not exposed. The protective element 13 or the piston body 2 have a ventilation channel 14, along which gas can be conducted past the protective element into a gap 12. The gap 12 extends at least partially between the piston body 2 and the protective element 13. From the gap 12, the gas enters the venting element 60, which is designed here as a simple bore 75. This bore opens into a nozzle 74 formed with a further bore. The nozzle 74 has an outlet opening 72, which in turn can be closed after the piston has been stopped.

Of course, the in FIGS. 7 to 10 shown variants of the venting elements for a ring piston 51 according to one of Fig. 4 to 6b be used.

Claims (15)

A piston (1, 50, 51) for a cartridge for storing a filling compound in a storage chamber of the cartridge, comprising a piston body (2, 52) having a delivery side (3, 53) and a drive side (3, 53) opposite the delivery side (3, 53). 4, 54) and a piston skirt (5, 55), wherein the piston skirt (5, 55) is arranged around a piston axis (9) and the piston body (2, 52) is surrounded on the circumference by the piston skirt (5, 55), wherein the piston skirt has a sealing element for forming a fluid-tight connection between the sealing element of the piston skirt (5, 55) and an inner wall of the reservoir chamber of the cartridge, so that the sealing element, when installed, forms a fluid-tight connection between the delivery side (3, 53) and the drive side ( 4, 54), characterized in that the piston body (2, 52) comprises a first and a second venting element (60, 61) through which the delivery side (3, 53) and the drive side (4, 54) by each a bore (75) are connectable to each other and the piston body (2, 52) has a vent slot (71, 73) which on the delivery side (3, 53) is arranged. Piston according to claim 1, wherein for at least one of the first or second venting elements (60, 61) a first inlet opening (62) and a second inlet opening (63) are provided, which open into the bore (75), so that gas from the delivery side ( 3, 53) on the drive side (4, 54) is conductive. Piston according to claim 1 or 2, wherein a first and second bore are provided. Piston according to one of the preceding claims 2 or 3, wherein the vent slot (71, 73) with the first and second inlet port (62, 63) is in communication. Piston according to one of the preceding claims, wherein at least one of the bores has a longitudinal axis (70) which is aligned substantially parallel to the longitudinal axis of the piston (9). Piston according to one of the preceding claims, wherein at least one of the inlet openings (62, 63) at an angle (77) to the longitudinal axis (70) of the venting element (60, 61) is aligned. A piston according to claim 6, wherein the angle (77) is greater than 10 ° to and including 90 °, preferably greater than 20 ° to and including 90 °, more preferably greater than or equal to 30 ° to and including 90 °. Piston according to one of the preceding claims, wherein the bore (75) contains at least one kink. Piston according to one of the preceding claims, wherein the bore (75) contains at least one curvature. Piston according to one of the preceding claims, wherein the bore (75) contains at least one throttle element. Piston according to one of the preceding claims, wherein the minimum diameter of the bore (75) is greater than 1/40 of the diameter of the piston. Piston (51) according to one of the preceding claims, comprising an inner piston skirt (55), wherein the inner piston skirt (55) delimits the piston body (52) on an inner side (59) facing the piston axis (9), comprising an inner sealing element for production a sealing contact with a wall of a disposed inside the inner piston skirt inner tube is suitable. Piston according to one of the preceding claims, wherein on the drive side (4, 54) stiffening ribs (15, 65) for connecting the Piston jacket (5, 55) with the piston body (2, 52) are arranged and / or a Kippsicherungselement (18, 64) is arranged. Discharge device comprising a piston (1, 51, 52) according to one of the preceding claims. Discharge apparatus according to claim 14, comprising a cartridge (17) for discharging a plurality of components, wherein the components are arranged in juxtaposed or coaxially arranged storage chambers of the cartridge.

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