Piston for dispensing a flowable component from a cartridge

Abstract

A piston for dispensing a flowable component from a cartridge includes a piston having a base body and a venting element. The base body has a passage connecting a component side and an actuation side and has a passage opening. The venting element has an internal connection element and a pin which is partly arranged in the passage opening of the base body. The internal connection element and the pin are connected by a spring element. The pin of the venting element can adopt a sealing position and an aerating position. To enable a secure sealing, the spring element is configured such that it includes an angle of a maximum of 80 with the axial direction in the sealing position of the pin at a connection line to the internal connection element in the direction of an actuation side.

Claims

1. A piston for dispensing a flowable component from a cartridge, the piston comprising a base body; and a venting element, the base body having a component side, an actuation side and a passage connecting the component side and the actuation side and having a passage opening; the venting element having an internal connection element by which the venting element is connected to the base body, and having an internal surface extending in an axial direction in a direction of the actuation side; a pin arranged at least partly in the passage of the base body, and a spring element connecting the internal connection element and the pin, and which is connected to the internal connection element along a connection line defined by the internal surface of the internal connection element, the pin of the venting element configured to adopt a sealing position in which the pin is aligned along the axial direction and the passage opening is closed in an airtight manner, and an aerating position in which an exchange of air is capable between the component side and the actuation side via the passage, the venting element being arranged and configured such that the spring element is configured to urge the pin into the sealing position, and the spring element extending from the internal connection element so as to define an angle of a maximum of 80 with the internal surface of the internal connection element at the connection line in the sealing position of the pin.

2. The piston in accordance with claim 1, wherein the spring element has a frustoconical contour in a region of the connection line to the internal connection element.

3. The piston in accordance with claim 1, wherein the internal connection element has a predominantly cylindrical base shape and is connected to the base body via an internal latch connection.

4. The piston in accordance with claim 3, wherein the internal latch connection has a first recess and a second recess and corresponding first and second dimples, with the first and second recesses being arranged spaced apart in the axial direction.

5. The piston in accordance with claim 1, further comprising an external connection element by which the venting element is connected to the base body, with the internal connection element being arranged between the external connection element and the pin.

6. The piston in accordance with claim 1, wherein the base body and the venting element are manufactured by an injection molding process.

7. The piston in accordance with claim 6, wherein the base body and the venting element comprise different materials.

8. The piston in accordance with claim 1, wherein the spring element has a frustoconical contour in a region of the connection line to the internal connection element.

9. The piston in accordance with claim 1, wherein the internal connection element has a predominantly cylindrical base shape and is connected to the base body via an internal latch connection.

10. The piston in accordance with claim 2, wherein the internal connection element has a predominantly cylindrical base shape and is connected to the base body via an internal latch connection.

11. The piston in accordance with claim 1, further comprising an external connection element by which the venting element is connected to the base body, with the internal connection element being arranged between the external connection element and the pin.

12. The piston in accordance with claim 2, further comprising an external connection element by which the venting element is connected to the base body, with the internal connection element being arranged between the external connection element and the pin.

13. The piston in accordance with claim 3, further comprising an external connection element by which the venting element is connected to the base body, with the internal connection element being arranged between the external connection element and the pin.

14. The piston in accordance with claim 4, further comprising an external connection element by which the venting element is connected to the base body, with the internal connection element being arranged between the external connection element and the pin.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) The invention will be explained in more detail hereinafter with reference to the drawings.

(2) FIG. 1 is a sectional representation of a piston in a cartridge which is only indicated; and

(3) FIG. 2 is a detail of the piston of FIG. 1 in an enlarged representation.

DETAILED DESCRIPTION OF THE EMBODIMENTS

(4) In accordance with FIG. 1, a piston 10 for dispensing a flowable component from a cartridge 11, only indicated, has a base body 12 and a venting element 13. The cartridge 11 has an annular cross-section at least in the region in which the piston 10 is arranged. An external storage space 14 thus results for a first component, not shown, and an internal storage space 15 for a second component, likewise not shown, which is arranged within the external storage space 14. The piston 10 is configured as a so-called ring piston and is thus arranged in the external storage space 14. An inner piston, not shown, is configured to dispense the second component in the internal storage space 15. The cartridge 11 has a volume of 50-1500 ml, for example.

(5) The base body 12 has an actuation side 16 via which it and thus the piston 10 can be acted on with an actuation force by a plunger, not shown, and can thus be displaced within the cartridge 11 in the direction of an axial direction 17 in the direction of an outlet, not shown, of the cartridge 11. The first component located in the external volume space 14 can thus be dispensed. The base body 12 additionally has a component side 18 at the side disposed opposite the actuation side 18 and the venting element 13 is arranged at the component side. The venting element 13 is designed such that it covers the complete component side 18 of the base body 12 with the exception of a peripheral marginal region 19.

(6) The base body 12 has at its external marginal region a peripheral groove 20 in which a predominantly hollow cylindrical external connection element 21 of the venting element 13 dips. The groove 20 and the connection element 21 have corresponding projections, not shown in any more detail, which are configured such that the external connection element 21 latches into the groove 20.

(7) In a region of the piston 10, the base body 12 has a cup-shaped passage 22 at which base a predominantly cylindrical passage opening 23 is arranged. The passage 22 connects the actuation side 16 and the component side 18 of the base body 12 of the piston 10. The section through the piston 10 shown in FIG. 1 extends centrally through the passage 22. The region of the piston 10 with the passage 22 is shown in enlarged form in FIG. 2.

(8) The venting element 13 has a pin 24 which is arranged partly in the passage 22 of the base body 12 and which projects through the passage opening 23. The pin 24 is connected to a predominantly hollow cylindrical internal connection element 26 via a spring element 25, with a circular connection line 27 resulting on the transition from the spring element 25 to the connection element 26. The spring element 25 has a thickness of approximately 0.5 mm. The internal connection element 26 dips into a corresponding recess 28 of the base body 12. The internal connection element 26 has two dimples 29, 30 which are arranged offset with one another in the axial direction 17. The recess 28 of the base body 12 has two corresponding recesses 31, 32 into which the two dimples 29, 30 latch in the shown assembled state of the piston 10 and thus ensure a secure fixing of the connection element 26 and thus of the total venting element 13 with respect to the base body 12. The dimples 29, 30 and the corresponding recesses 31, 32 thus form an inner latch connection between the internal connection element 26 and the base body 12.

(9) In a sealing position shown in FIGS. 1 and 2, the pin 24 closes the passage opening 23 of the base body 12 in an airtight manner so that no exchange of air can take place between the actuation side 16 and the component side 18. To achieve a secure sealing, the pin 24 has a slightly conical extent in a region so that it tapers slightly in the direction of the actuation side 16. The passage opening 23 has a corresponding contour so that a large sealing surface results. The pin 24 is aligned along the axial direction 17 in the sealing position. The pin 24 can be brought out of the sealing position shown into an aerating position, not shown, by displacing the pin 24 against a preload force of the spring element 25 in the direction of the component side 18 by a plunger, not shown. In the aerating position, the pin 24 is arranged with respect to the passage opening 23 such that an annular aerating gap results between the pin 24 and the passage opening 23 via which aerating gap an exchange of air is possible between the component side 18 and the actuation side 16.

(10) The spring element 25 has a frustoconical contour in the region of the connection line 27 to the connection element 26. The spring element 25 is configured and arranged such that it includes an angle of approximately 70 with the axial direction 17 in the sealing position of the pin 24 at the connection line 27 to the internal connection element 26 in the direction of the actuation side 16. The connection line 27 is to be understood as the line on the side of the venting element 13 which is aligned in the direction of the actuation side 16 and at which the internal connection element 26 merges into the spring element 25. The angle then results in FIG. 2 between a tangent 33 at a point of the connection line 27 at the contour of the spring element 25 aligned in the direction of the actuation side 16 and the axial direction 17. For better clarity, the tangent is additionally shown displaced in the direction of the component side 18 (reference numeral 33).

(11) The base body 12 and the venting element 13 are each manufactured by an injection molding process. The base body 12 in this respect comprises polyethylene and the venting element 13 comprises polyamide.