VALVE COUPLING

Abstract

The invention relates to a valve coupling (1.1) having a discharge part (2.1) and a receiving part which can be coupled to the discharge part and which has a valve function which, in the coupled state, allows the transmission of a fluid or paste-like material from the discharge part to the receiving part. In the decoupled state, the discharge part and the receiving part are closed in a fluid-tight manner. The discharge part has a discharge valve, and the receiving part (3.1) has a receiving valve. The coupling or decoupling results in an opening or closing of the valves and is carried out by elastic deformation, wherein, in the case of coupling, the valves are opened only when the discharge part is connected to the receiving part in a fluid-tight manner, and in the case of decoupling, the valves are closed before the fluid-tight connection is broken.

Description

The invention relates to a valve coupling having a discharge part and a receiving part to transmit a liquid or paste-like agent. The invention also relates to an electric razor or an electric oral care device, for example an electric toothbrush, with a fluid-tight separation between a handle part and an attachment that can be connected to it.

A corresponding valve coupling is known, for example, from DE 19704920 A1. After the transmission of a liquid or paste-like agent and the subsequent separation of the discharge part from the receiving part, residues of the agent can get stuck the discharge part and the receiving part and dry out due to the design, so that on a subsequent coupling of the discharge part with the receiving part, the transmission of a liquid or paste-like agent may be blocked.

In contrast, the object of the invention is to create an improved valve coupling, in which the function of the valve coupling is not jeopardized. A further object of the invention is to provide an electric razor or an electric oral care device, for example an electric toothbrush, which is improved with regard to a liquid-tight separation between a handle part and an attachment which can be connected to it.

This object is achieved according to claim 1 in that a valve coupling, which has a discharge part and a receiving part which can be coupled to the discharge part and which has a valve function that allows the transmission of a fluid or paste-like material from the discharge part to the receiving part in the coupled state, and which, in the decoupled state, the discharge part and the receiving part are closed in a fluid-tight manner and the discharge part has a discharge valve, and the receiving part has a receiving valve, and the coupling or decoupling results in an opening or closing of the valves carried out by means of elastic deformation, wherein, in the case of coupling, the valves are opened only when the discharge part is connected to the receiving part in a fluid-tight manner, and in the case of decoupling, the valves are closed before the fluid-tight connection is broken. Further advantageous embodiments of the invention arise from the subclaims.

A first embodiment provides that the discharge part is finger-shaped and hollow, that at least one round end portion of the discharge part is made of an elastic material and has a valve slit, that the receiving part has an indentation with a round end with a slit valve and is made of an elastic material, and that in the coupled state, an outer surface of the round end of the discharge part and an inner surface of the round end of the receiving part are joined together in a friction lock or a positive lock, whereby an opening is prevented in which residues of free flowing agents can accumulate, harden and dry or clump together in the discharge part and the receiving part, and thus a reliable function of the valve coupling is ensured.

The round end of the discharge part is designed, for example, as a hollow finger shaped one-piece molded component, which comprises a rigid sleeve below the round end, whereby, on the one hand, the discharge part maintains mechanical stability, and on the other hand, the form of the round end region remains elastic. The receiving part is preferably provided with a rib brace on two opposite outer sides transverse to the length of the second valve slit, whereby, in terms of valve function (closing function), compensating for the fatigue effect of the material. For easy mounting, a flange can be molded in one piece on the receiving part, which is made more rigid by a reinforcing ring. A seal ring can be formed on the flange for attaching the receiving part in a liquid-tight manner.

A second embodiment provides that the discharge part is finger-shaped and hollow, that a round end of the discharge part consists of an elastic material and has a valve slit, that the receiving part has a concave round end with a slit valve and consists of an elastic material, that the receiving part is designed to be axially resilient, and that an outer surface of the round end of the discharge part and an outer surface of the concave top of the receiving part friction locks or positively fits with each other in the coupled state, wherein an opening is prevented in which the residue of the agent in the discharge part and the receiving part can accumulate, harden, dry or clump, and thus a reliable function of the valve coupling is ensured.

The round end of the discharge part is preferably designed as a hollow finger shaped one-piece molded component, which comprises a rigid sleeve below the round end, whereby, on the one hand, the discharge part maintains mechanical stability, and on the other hand, the form of the round end region remains elastic. The receiving part has an axially resilient zone which is formed by means of a rotationally symmetric constriction. By this means, the outer surface of the round end and the outer surface of the concave round end are friction locked or positively fit with each other in the coupled state.

In a third embodiment, it is provided that the discharge part has a hollow needle with a round end, that the hollow needle has a cross-hole below the round end which is encased in a rubber sleeve, that the receiving part has a component made of an elastic material and is provided with a slit, and that in the coupled state, the hollow needle with the cross-hole is inserted through the slit, and in the process, the rubber sleeve is reversibly withdrawn through the component, that the cross-hole is released, whereby an opening is prevented in which residues of free flowing agents can accumulate, harden and dry or clump together on the discharge part and the receiving part, and thus reliable functioning of the valve coupling is ensured.

On the free end, the rubber sleeve preferably has a reinforcing ring made of rigid material that serves as an end stop surface for the axial displacement of the rubber sleeve, wherein the receiving part has a support ring made of rigid material, which corresponds to the reinforcing ring for axial displacement. The hollow needle is preferably encased by the rubber sleeve having a small amount of clearance, which facilitates the axial displacement of the rubber sleeve on the needle. The rubber sleeve preferably has an internal seal ring which seals the cross-hole of the hollow needle from the outside in the coupled state, whereby no residue forms, accumulates, hardens or clumps outside of the hollow needle or cross-hole.

In an exemplary example it is provided that the valve coupling is arranged in an electric razor or in an electric oral care device, for example an electric toothbrush, as a separating point between a handle part and an attachment to be connected to it.

The invention will be described according to three embodiments.

FIG. 1 shows in a sectional side view of the discharge part and the receiving part as a first embodiment of a valve coupling;

FIG. 2 shows a sectional side view of a discharge part;

FIG. 3 shows in a sectional side view of a receiving part;

FIG. 4 shows a partial sectional side view of the valve coupling according to FIG. 1 through 3 in an electric toothbrush with a handle part and a brush attachment component that can be connected thereto;

FIG. 5 shows a perspective side view of the discharge part according to FIG. 2;

FIG. 6 shows a perspective side view of the receiving part according to FIG. 3;

FIG. 7 shows a perspective side view of the valve coupling according to FIG. 1, however with two ribs arranged opposite each other;

FIG. 8 shows a sectional side view of a discharge part and a receiving part as a second embodiment of a valve coupling;

FIG. 9 shows a perspective side view of the valve coupling according to FIG. 8;

FIG. 10 shows an enlarged representation of the round end region according to FIG. 8;

FIG. 11 shows a sectional side view of a discharge part and a receiving part as a third embodiment of a valve coupling; and

FIG. 12 shows the valve coupling according FIG. 11, but in the coupled state.

FIG. 1 shows sectional side view of a self-sealing coupling valve 1.1 with a discharge part 2.1, and a receiving part 3.1 almost in a final position of the coupled state for trasmitting a liquid or paste-like agent 35. The discharge part 2.1 is formed finger-shaped and hollow, wherein at least a round end 5.1 of the discharge part 2.1 is made of an elastic material 37 and has a valve slit 6.1 of a first slit valve 4.1 as a discharge valve 101 (FIG. 2). The thimble-like receiving part 3.1 has a indentation 7 with a round end 5.2 with a valve slit 6.2 of a second slit valve 4.2 as a receiving valve 102 (FIG. 3), and is made of an elastic material 37. In the coupled state, the outer surface 8.1 (FIG. 2) of the round end 5.1 of the discharge part and the inner surface 9 (FIG. 3) of the round end 5.2 of the receiving part are coupled to each other by means of a friction lock or positive fit, wherein the pressure of the agent 35 is transmitted through the expanded outer surface 8.1 onto the inner surface 9 of the round end 5.2, and thus the valve slit 6.2 and the slit valve 4.2 are opened, whereby an opening is prevented in which the residue of the agent 35 could accumulate on discharge part 2.1 and on the receiving part 3.1. An annular surface 43 of the end piece of a sleeve 16 of the discharge part and an annular surface 44 on the inner round end 5.2 of the receiving part form a stop.

The arrow 34 shows the direction of flow (entrance) of the agent 35 in the discharge part 2.1; the arrow 38 shows the direction of flow (exit) of the agent 35 out of the receiving part 3.1, for example, into a brush attachment 33 according to FIG. 4.

FIG. 2 shows a sectional side view of the discharge part 2.1, which consists of a hollow finger shaped one-piece molding 15 made of elastic material 37 and a rigid sleeve 16 made of a hard material—preferably of stainless metal—wherein the molded component 15 is connected with the sleeve 16 below the round end 5.1, preferably by vulcanization, for stiffening and for stationary mounting of the discharge part 2.1. The discharge part 2.1 is constructed in such a way that only the area of the round end 5.1 with a valve slit 6.1 is resilient and can thus adapt itself to the inside 9 of the receiving part 3.1. The round end 5.1 of the elastic molded component 15 is convexly curved outward, so that the pressure of the agent 35 arising from the inside expands the round end 5.1 outward and thus the valve slit 6.1 and the slit valve 4.1 are opened.

FIG. 3 shows a sectional side view of the receiving part 3.1. In the forward area of indentation 7, the receiving part 3.1 is provided with a radial circumferential flange 21 and with a rigid support ring 22, which is firmly mounted to the flange 21. A seal ring 36 molded to the flange 21 is used for the fluid-tight assembly of the receiving part 3.1, wherein the rigid support ring 22 stabilizes the flange 21 as an assembly aid. The receiving part 3.1 can be attached into a detachable component, for example, in particular into a detachable brush head 33 (FIG. 4) for an electric toothbrush.

Together, FIGS. 2 and 3 show the valve coupling 1.1 before or after a coupling of the discharge part 2.1 with the receiving part 3.1.

As FIG. 4 shows, the discharge part 2.1 can be designed at the outlet of the fluid channel as a handle part 32 of an electric toothbrush, and the receiving part 3.1 can be designed at the inlet of a fluid channel as receiving element in the detachable brush head 33. To prevent leakage of the agent 35 in the coupled state, and to prevent its drying up in the uncoupled state, the round end 5.1 of the of the discharge part 2.1 is provided with a valve slit 6.1 and the round end 5.2 of the receiving part 3.1 is provided with valve slit 6.2. The slit valves 4.1, 4.2 seal in one direction like a one-way valve. Due to the pressure exerted on the round end 5.1 of the discharge part 2.1 created by pumping on the agent 35, the valve slit 6.1 of the first slit valve 4.1 expands and opens.

The receiving part 3.1 in the detachable brush head 33 also has the shape of a round end 5.2 with a valve slit 6.2 for the transmission of the agent 35. This round end 5.2 has an inner diameter such that the round end 5.1 of the first slit valve 4.1 fits in it exactly. After coupling, a small excess of radial or axial pressure is exerted on the slit valve 4.1, for example, by small externally lying ridges from within the slit valve 4.2. Thus the valve slit 4.2 of the round end 5.2 opens when both the slit valves 4.1, 4.2 are joined. The slit valve 4.1 is opened by the pressure of the agent 35 arising from within; the slit valve 4.2 is opened by the pressure exerted by the slit valve 4.1 on the slit valve 4.2 after they have been joined together. After separating the valve coupling 1.1, both slit valves 4.1, 4.2 close due to the tension in the material 37.

FIG. 4 shows a partial sectional side view of the valve coupling 1.1 according to FIGS. 1 through 3 in an electric toothbrush 31 with a handle part 32 and a detachable brush head 33. In the handle part 32, a reservoir for the medium 35 is arranged on the discharge part 2.1 with a pump and a fluid channel 51, wherein the agent provided 35 is for example a dental care product that can be transmitted through the valve coupling 1.1 and through a liquid channel 52 into the detachable brush head 33. The pump provides the necessary pressure build-up to transmit or convey the medium 35 through the valve coupling into the detachable brush head 33.

With electrical devices for personal use, it may be advantageous to support the mechanical action of the device with liquid agents, which are applied during use. Thus it can be advantageous to apply a pre-shave lotion in an electric razor while shaving, which supports easy gliding on the skin and reduces skin irritation. Particularly with electric toothbrushes, it may be advantageous to pump a dental care substance before and during cleaning from a reservoir in the handle part into the brush head, thus always providing the optimal amount of fresh material.

FIG. 5 shows a perspective side view of the discharge part 2.1 according to FIG. 1. FIG. 6 shows a perspective side view of the receiving part 3.1 according FIG. 3.

FIG. 7 shows a perspective side view of the valve coupling according to FIG. 1, wherein the receiving part 3.1 in each case additionally has tensioning ribs 19, 20 on two opposite outer sides 17, 18, transverse to the length of the second valve slit 6.2.

Since the receiving part 3.1 in the coupled state is under constant tension, it is possible that the effects of aging of the elastic material 37 will cause the valve slit 6.2 to no longer completely close, thus making the slit valve 4.2 leaky. In order to avoid this, the slit valve 4.2 is put under slight tension from the outside. To this end, two or more small ribs 19, 20 opposite each other are formed on the outside of the receiving part 3.1. When the round end 5.1 is joined in the indentation provided for it, this causes the round end 5.2 to be placed under an inward tension, which presses the second valve slit 6.2 more firmly closed, compensating for the fatigue of the material 37.

Since the two dome-shaped slit valves 6.1, 6.2 lie close together in the coupled state, the quantity of agent 35 or toothpaste which could escape into the space between the two slit valves 6.1, 6.2 is extremely small, the risk of blockage or of sticking is virtually eliminated. It has proven to be advantageous to axially pretension the receiving part 3.1 in the replaceable brush head 33 via the discharge part 2.1. In this way, there is always a small area of contact of the round ends 5.1, 5.2 against each other, resulting in virtually no significant volume that could be filled with the agent 35. Because of the axial pretensioning after coupling, which can vary in the range of a few tenths of a millimeter to two or more millimeters, because of the effect of positioning tolerances, a secure seal to the outside is achieved and an opening of the valve of the receiving part of 3.1 is also given.

A second embodiment example of a valve coupling 1.2 with a discharge part 2.2 and a receiving part 3.2 in the coupled state for transmitting a liquid or paste-like agent 35 is shown in FIG. 8, in a sectional side view. The discharge part 2.1 is formed finger-shaped and hollow, wherein a round end 5.3 of the discharge part 2.2 is made of an elastic material 37 and has a valve slit 6.3 of a slit valve 4.3 as a discharge valve 103. The receiving part 3.2 is provided with a concave round end 5.5 with a valve slit 6.4 of a slit valve 4.4 of a receiving valve 104, and is made of an elastic material 37. The receiving part 3.2 is designed to be axially resilient. In the coupled state, an outer surface 8.2 of the round end 5.3 and an outer surface 8.3 of the concave round end 5.5 are joined to each other by means of a friction lock or positive fit, wherein a seal ring 47 around the concave round end 5.5 is sealed against the exterior in contact with the end piece 48 of the sleeve 24.

The round end 5.3 of the discharge part 2.2 is designed as a hollow finger shaped one-piece molded component 23, which comprises a rigid sleeve 24 below the round end 5.3 made of a hard material—preferably stainless metal. The sleeve 24 serves for stiffening and for stationary mounting of the molded component 23 and is securely joined to the molded component, preferably by vulcanization. In this way, the discharge part 2.2 is constructed in such a way that only the area of the round end 5.3 with the valve slit 6.3 is shape elastic.

The receiving part 3.2 has an axially resilient zone 25 which is formed by means of a rotationally symmetrical constriction 26. In this way, a resilient coupling of the receiving part 3.2 with the discharge part 2.2 is achieved.

FIG. 9 shows a perspective side view of the valve coupling 1.2 according to FIG. 8.

FIG. 10 shows an enlarged representation of the area of the round end 5.3 and the concave round end 5.5 according to FIG. 8. A particularly high flexibility of the round end 5.3 is achieved in that an annular gap 40 is arranged in the end area 41 between the sleeve 24 and the discharge part 2.2, whereby the molded component 23 can move radially when an axial pressure is applied to the outside aperture (compression). In addition, the sleeve 24 provides a mechanical protection for the elastic component 23.

The two elastic round ends 5.3, 5.5 are joined with each other on the end face with allowance for interference, wherein the frontal surfaces of the round ends 5.3, 5.5 are complementarily curved. The receiving part 3.2 is constructed so that it can easily be elastically shortened axially by deformation. In this way, the pressure exerted by the two round ends 5.3, 5.5 on the convex face builds tension in the material in the coupled state. In this way, the valve slit 6.3 in the convex component is opened. Thus, a slit valve 4.3 is opened already after the coupling as a discharge valve 103 and should not be opened by pressure build-up of the agent 35.

A third embodiment example of a valve coupling 1.3 with a discharge part 2.3 and a receiving part 3.3 for transmitting a liquid or paste-like agent 35 is shown in FIG. 11 in a sectional side view. The discharge part 2.3 has a hollow needle 10 with a round end 5.4, wherein the hollow needle 10 has a cross-hole 11 below the round end 5.4, which is encased by an elastic sleeve, for example, a rubber sleeve 12, which seals the cross-hole 11 to the outside in the coupled state, and in this way creates a discharge valve 105 so that the liquid 35 in the cannula 42 of the hollow needle 10 does not leak out or dry up. FIG. 11 shows the situation immediately prior to coupling. The receiving part 3.3 has a component 13 made of an elastic material and is provided with a slit 14, and forms a receiving valve 106. A depression 49 is arranged inside around slit 14. In the coupled state (FIG. 12), the hollow needle 10 extends through the slit 14 with the cross-hole 11. The rubber sleeve 12 is thereby reversibly withdrawn through the component 13 such that the cross-hole 11 is released.

On the free end, the rubber sleeve 12 has a reinforcing ring 27 made of rigid material that serves as an end stop surface for the axial displacement of the rubber sleeve, wherein the receiving part 3.3 has a support ring 28 made of rigid material, which corresponds to the reinforcing ring 27 for axial displacement. The hollow needle 10 is preferably encased by the rubber sleeve 12 having a small amount clearance 29, which facilitates the axial displacement of the rubber sleeve 12 on the needle 10.

The rubber sleeve 12 preferably has an internal seal ring 30 which, in the coupled state, seals the cross-hole 11 from the outside. An additional internal seal ring 50 of the rubber sleeve 12 under the cross-hole 11 ensures that no further contamination of the agent 35 can occur across the area of the cross-hole 11 out onto the exterior side of the hollow needle 10.

FIG. 12 shows the valve coupling 1.3 according to FIG. 11, but in the coupled state during the transmission of a liquid or paste-like agent 35. The hollow needle 10 is inserted through the slit 14 of the component 13, wherein the agent 35 is discharged out of the cross-hole 11 through the depression 49. When compressed, the rubber sleeve 12 is deformed outwardly.

The closed end hollow needle 10 with a transverse hole 11 sits in a cylindrical rubber sleeve 12. When it is in a relaxed state, the rubber sleeve 12 seals the cross-hole 11 in the steel needle 42 from the outside. The corresponding component is an elastic component 13, which has a slit 14 in the middle. During the coupling of the third discharge part 2.3 with the receiving part 3.3, an annular surface 45 of the end piece of the rubber sleeve 12 is settles onto an annular surface 46 around the slit 14 and radially sealed towards the outside. Then the (steel) hollow needle 10 penetrates through the slit 14 in the elastic component 13 of the counter component and the rubber sleeve 12 around the hollow needle 10 is compressed and deformed. In the coupled state, the cross-hole 11 is in the cannula 42 below the seal ring 36 of the elastic component 13. In this way, sealing the cannula 42 to the outside is ensured. When the valve coupling 1.3 is separated, the rubber sleeve 12 takes on its original shape again after the hollow needle 10 is withdrawn the slit 14 closes. Thus, the elastic component 13 seals and the seal ring 30 in the cylindrical rubber sleeve 12 pushes back across the cross-hole 11 and again seals off the system (discharge part 2.3 and receiving part 3.3).

Thus, the invention includes a serial combination of two valves 4.1-4.4 at a coupling site (valve coupling 1.1-1.3) of a liquid stream. Two valves are provided at the ends of two fluid channels that are open after the separation of the components. In their coupled state, these valves (slit valves 4.1-4.4) seal off from the outside, so that no free-flowing agent 35 can leave the fluid channels. After separating the coupled site, the valves also seal the now open channels from the outside, so that no agent 35 can escape or the channels quickly dry out through loss of moisture. Through a clever design of the valves 4.1-4.4, the agent 35 remains practically completely within the sealed area, even after separation of the valves 4.1-4.4 and does not escape to the outside. Thus the risk of dried remnants of the agent 35 blocking the coupling body or the valve is practically non-existent. The valves 4.1-4.4 are constructed and arranged so that they can be arranged well in series in the smallest of spaces.

LIST OF REFERENCE NUMERALS

• 1.1 valve coupling
• 1.2 valve coupling
• 1.3 valve coupling
• 2.1 discharge part
• 2.2 discharge part
• 2.3 discharge part
• 3.1 receiving part
• 3.2 receiving part
• 3.3 receiving part
• 4.1 slit valve
• 4.2 slit valve
• 4.3 slit valve
• 4.4 slit valve
• 5.1 round end
• 5.2 round end
• 5.3 round end
• 5.4 round end
• 5.5 concave round end
• 6.1 valve slit
• 6.2 valve slit
• 6.3 valve slit
• 6.4 valve slit
• 7 indentation
• 8.1 outside
• 8.2 outside
• 9 inside
• 10 hollow needle
• 11 cross-hole
• 12 rubber sleeve
• 13 component
• 14 slit
• 15 molded component
• 16 sleeve
• 17 outside
• 18 outside
• 19 tension rib
• 20 tension rib
• 21 flange
• 22 support ring
• 23 molded component
• 24 sleeve
• 25 resilient zone
• 26 rotationally symmetrical constriction
• 27 reinforcing ring
• 28 support ring
• 29 clearance
• 30 seal ring
• 31 electric toothbrush
• 32 handle part
• 33 brush attachment
• 34 arrow/flow direction (entrance)
• 35 medium
• 36 seal ring
• 37 elastic material
• 38 arrow/flow direction (outlet)
• 39 flange
• 40 annular gap
• 41 end area
• 42 cannula
• 43 annular surface
• 44 annular surface
• 45 annular surface
• 46 annular surface
• 47 seal ring
• 48 end/sleeve 24
• 49 depression
• 50 ring seal
• 51 channel
• 52 channel
• 101, 103, 105 discharge valves
• 102, 104, 106 receiving valves

Claims

1. A valve coupling with a discharge part and a receiving part which can be coupled to the discharge part with a valve function which, in the coupled state, allows the transmission of a fluid or paste-like material from the discharge part to the receiving part, wherein, in the decoupled state, the discharge part and the receiving part are closed in a fluid-tight manner, characterized in that the discharge part (2.1-2.3) has a discharge valve (101,103,105), and the receiving part (3.1-3.3) has a receiving valve (102, 104, 106), which when coupled or decoupled, results in an opening or closing of the discharge and receiving valves (101-16) carried out by means of elastic deformation, wherein, in the case of coupling, the valves (101-106) are opened only when the discharge part (2.1-2.3) is connected to the receiving part (3.1-3.3) in a fluid-tight manner, and in the case of decoupling, the valves (101-16) are closed before the fluid-tight connection is broken.

2. The valve coupling according to claim 1 characterized in that the discharge part (2.1) is finger-shaped and hollow, that a round end (5.1) of the discharge part (2.1) is made of an elastic material (37) and has a valve slit (6.1), that the receiving part (3.1) has an indentation (7) with a round end (5.2) with a valve slit (6.2) and is made of an elastic material (37), and that, in the coupled state, an outer surface (8.1) of the round end (5.1) and an inner surface (9) of the round end (5.2) are joined together in a friction lock or a positive lock.

3. The valve coupling according to claim 2 characterized in that the round end (5.1) of the discharge part (2.1) is formed by a hollow finger-shaped one-piece molded component (15) that comprises a rigid sleeve (16) below the round end (5.1).

4. The valve coupling according to any of the previous claims, characterized in that the receiving part (3.1) has in each case two tension ribs (19, 20) on two opposite outer surfaces (17, 18), transverse to the length of the valve slit (6.2).

5. The valve coupling according to any of the previous claims, characterized in the receiving part (3.1) has a flange (21), preferably with a molded seal ring 36.

6. The valve coupling according to any of the previous claims, characterized in the receiving part (3.1) has a flange (21) and a support ring (22).

7. The valve coupling according to claim 1, characterized in the discharge part (2.2) is hollow and finger shaped, that a round end (5.3) of the discharge part (2.2) is made of an elastic material (37) and has a valve slit (6.4), that the receiving part (3.2) has a concave round end (5.5) with a valve slit (6.4) and is made of an elastic material (37), that the receiving part (3.2) is formed axially resilient, and that, in the coupled state, an outer surface (8.2) of the round end (5.3) and an outer surface (8.3) of the concave round end (5.5) are joined together in a friction lock or a positive lock.

8. The valve coupling according to claim 7 characterized in that the round end (5.3) of the discharge part (2.2) is formed by a hollow finger shaped one-piece molded component (23) that comprises a rigid sleeve (24) below the round end (5.1).

9. The valve coupling according to claim 7 or 8, characterized in that the receiving part (3.2) has an axially resilient zone (25).

10. The valve coupling according to claim 9, characterized in that the axially resilient zone (25) is formed by means of a rotationally symmetrical constriction (26).

11. The valve coupling according to claim 1, characterized in that the discharge part (2.3) has a hollow needle (10) with a round end (5.4), that the hollow needle (10) has a cross-hole (11) below the round end (5.4) which is encased in an elastic sleeve (12), that the receiving part (3.3) has a component (13) made of an elastic material (37) and is provided with a slit (14), and that, in the coupled state, the hollow needle (10) with the cross-hole (11) is inserted through the slit (14), and in this process, the elastic sleeve (12) is reversibly withdrawn through the component (13) so that the cross-hole (11) is released.

12. The valve coupling according to claim 11, characterized in that the elastic sleeve (12) has a reinforcing ring (27) on the free end made of a rigid material.

13. The valve coupling according to claim 11 or 12, characterized in that the receiving part (3.3) has a support ring (28) made of rigid material.

14. The valve coupling according to claim 11 through 13, characterized in that the elastic sleeve (12) encases the hollow needle (10) with a clearance (29).

15. The valve coupling according to any of claims 11 through 14, characterized in that the elastic sleeve (12) has at least one interior seal ring (30, 50) which, in the uncoupled state, seals the cross-hole from the outside.

16. An electric razor or electric oral care device, for example an electric toothbrush (13) with a handle part (32) and a detachable brush head (33) which can be attached to it, with a valve coupling (1.1, 1.2, 1.3) according to any of the preceding claims.