GB2125276A

GB2125276A - Water ducting in an electric coffee machine

Info

Publication number: GB2125276A
Application number: GB08321031A
Authority: GB
Inventors: Udo Leuschner
Original assignee: Individual
Current assignee: Individual
Priority date: 1982-08-16
Filing date: 1983-08-04
Publication date: 1984-03-07
Also published as: GB2125276B; FR2531846A1; GB8321031D0

Abstract

An electric coffee machine comprises a cold water pipe (22) for conducting water from a freshwater container (16) to a water heater (12), from which a hot water pipe (72) leads to an outlet above a coffee filter (10). At least one of the cold water pipe (22) and the hot water pipe (72) comprises a hose of a relatively stiff synthetic material, which is, for example, manufactured by a blow-moulding process and which has a corrugated tube portion (46 or 74) for increasing flexibility and a deformed portion (42 or 80), preferably generated in the blow-moulding process, serving for fastening of the hose to a part (23 or 78) of the machine housing. <IMAGE>

Description

SPECIFICATION Water ducting in an electric coffee machine The present invention relates to an electric coffee machine and has particular reference to a machine in which a cold water pipe serves to conduct water from a freshwater container to a water heater and in which a hot water pipe serves to conduct water from the heater to an outlet above a coffee filter.

The cold water pipe and the hot water pipe in known coffee machines are usually manufactured from a resilient hose of silicone rubber, which at its connecting points is drawn over connecting stub pipes. Although these hoses are very temperature-resistant, they appreciably increase the production cost by reason of the relatively expensive material used. The drawing of the end portions onto the connecting stub pipe is relatively expensive in production. It frequently happens that hoses are pressed away from their seat when increased pressure pulses occur, for example in the case of a calcified machine, with the consequence that water runs out into the interior of the coffee machine housing, in which electrical components are disposed, and also out into the surroundings of the machine.If the coffee machine possesses operationally detachable components associated with the water paths, for example a removable freshwater container or a removable overflow pipe in the coffee filter, then a direct connection of the pipe to the removable component is not possible and an intermediate component must be employed, whereby the number of the sealing locations in the coffee machine becomes relatively high and the production cost is correspondingly increased.

Moreover, the cold water pipe is usually formed from two hose portions with the interposition of a valve, so that four hose connections are to be produced for the cold water pipe alone. A further disadvantage is that the hose ends, which are drawn over stub pipes and retained on these through their resilience, are not easy to assemble.

In addition, in the case of periodic increased pressures, for example due to calcification, in the machine the hoses can be pressed away relatively easily from their seats, with the consequences already mentioned.

There is thus a need for a coffee machine in which the security against detaching of hose connections can be increased with little production effort and preferably the number of the hose connections and components of the coffee machine can be reduced.

According to one aspect of the present invention there is provided an electric coffee machine comprising a housing, a water heater, a cold water pipe for conducting cold water from a freshwater container to the heater and a hot water pipe for conducting hot water from the heater to an outlet above a coffee filter, at least one of the pipes comprising a hose of stiff synthetic material having a corrugated portion enhancing the flexibility of the hose and a deformed portion for fastening of the hose to the housing.

Preferably, the hose is manufactured in a blowmoulding process and has corrugated tube portions for increasing flexibility and deformations preferably generated in the blow-moulding process and serving for fastening of the hose to housing parts of the coffee machine. This has the advantage that the end portions of the hose are fixable in the housing in the region of their connecting locations and the connecting locations can thereby be secured against slipping off, or the relatively stiff hose ends can serve directly as connectors for operationally detachable waterconducting components of the coffee machine, whereby the number of components and the number of sealing locations and thereby the production cost of the machine is reduced.The deformations are preferably produced in the blowmoulding process, but they can be subsequently produced through local heating and thermoplastic deformation of the third-walled hose.

Preferably, resilient detent hooks, which cooperate with the deformations, are formed at the rim of a passage. opening, receiving the hose, of a housing part, wherein concavities or convexities preferably produced in the blow-moulding process serve as deformations. In that case, an elongate prismatic convexity, for example having the form of a cylindrical drum, can rest at one end against the rim of the passage opening and be guided by its circumference between a ring of at least three detent hooks extending substantially parallel to the convexity, wherein detent lugs of the detent hooks arranged at the part with the passage opening can notch in behind the other end of the convexity in order to retain it.The detent hooks in this manner not only hold the hose fast, but also align it, which is particularly advantageous when the end portion of the hose serves as a connector for operationally detachable components such as freshwater container and an overflow pipe.

Preferably, an annular seal is arranged in an encircling circumferential deformation at the tube portions serving for the water-tight connection of the hose.

According to another aspect of the present invention at least one of the cold water pipe and the hot water pipe comprises a hose of a relatively stiff synthetic material, which hose is for example manufactured in a blow-moulding process and which has corrugated tube portions for increasing flexibility and in which a valve seat is formed.

Usually, only one non-return valve is employed in the cold water pipe, although it is also known to employ in the cold water pipe or the hot water pipe a valve which acts in an equalising manner on the flow speed in that it throttles according to speed. It is also known to incorporate a thermostatically or temporaliy actuated blocking or throttle valve in the cold water pipe or the hot water pipe in order to avoid the conveying of an initial cold water quantity before hot water conveying commences.

The valve seat is preferably formed in an end portion of the hose, which facilitates the introduction of a valve body. Serving as the valve seat can be an inwardly directed, encircling circumferential concavity which is formed during the production of the corrugations of the hose in the blow-moulding process without additional effort. At a spacing therefrom, concavities are formed on and distributed around the circumference of the hose and prevent the valve body, for example a ball, from moving too far from the valve seat, the concavities being so dimensioned and arranged that the valve body is pressable during the assembly past the concavities. Additionally, a valve spring cooperating with the valve body and the concavities can be incorporated.By virtue of the resilience of the valve spring, it is possible to use in place of the individual concavities a circumferential concavity or convexity of the hose for supporting the spring.

If the hose with the valve seat is produced from a less heat-resistant synthetic material, a short portion of a resilient highly temperature-resistant tube can be employed for effecting the connection to the water heater. For this case, the formation of the valve in the connecting end portion of the hose is particularly advantageous, as the concavities and/or convexities substantially improve the anchoring of the tube.

An embodiment of the present invention will now be more particularly described by way of example with reference to the accompanying drawings, in which: Fig. 1 is a vertical section of part of an electric coffee machine embodying the invention; and Fig. 2 is a cross-section of a modified form of a cold water hose in the region of its connection to a water heater of the machine.

Referring now to the drawings, there is shown in Fig. 1 an electric coffee machine comprising a pedestal housing 2 with an inserted bottom 4 and a warming plate 6 placed below a cover-sided opening of the right-hand lower part. A coffee can 8 with a coffee filter 10 placed thereon stands on the warming plate 6. A throughflow water heater 12 with a water tube 14 is built onto the underside of the warming plate 6. The elevated part of the pedestal housing 2 projecting up to the left beside the warming plate possesses a recess on the side remote from the can 8, into which recess is inserted an operationally detachable freshwater container 16, which has a tubular connecting stub pipe 1 8 at its bottom side. The stub pipe 1 8 projects down into a bottom trough 20, not occupied by the container 1 6, of the recess.A cold water pipe, in the form of a hose 27 of stiff synthetic material, projects upwardly by an end portion 24 through the bottom 23 of the trough 20 into the stub pipe 18 and has a circumferential constriction in which a resilient annular seal 26 of circular cross-section lies and co-operates sealings with the stub pipe 1 8.

The container 1 6 has a bottom 28 with a round outlet opening 30 into the stub pipe 18, through which opening a valve shank 32 projects and at its upper end portion carries a resilient sealing plate 34 snap-fitted into an annular groove. Formed at the lower end of the shank 32 is a rib star 36, the upper side of which co-operates with a valve spring 38 bearing against the bottom 28 of the container 1 6 and the underside of which cooperates with an upper narrowed closing portion 40 of the end portion 24 of the hose 22. When the container 1 6 is inserted, the star 36 lifts the sealing plate 34 from its seat against the force of the valve spring 38 and makes possible the throughfiow of water.

The hose 22, which over its entire length has substantially the same wall thickness and is produced in a blow-moulding process, is provided underneath the bottom 23 of the trough 20 with a cylindrical enlargement 42. The upper edge of the enlargement 42 rests against the bottom 23 and under the lower edge thereof engage six detent hooks 44, which are formed at the underside of the bottom 23 and distributed around the circumference, in order to fasten the end portion 22 to the housing 2. A corrugated tube portion 46, which is bent through 900, is formed in the hose 22 at a spacing below the enlargement 42 so that a lower end portion 48 of the hose 22 is aligned with the water tube 14 of the heater 12 and is connected with this by a resilient highly temperature-resistant hose or tube 50 drawn onto both ends.

At a spacing from the free end for the formation of a non-return valve 52, the end portion 48 has an annular constriction 54, with which cooperates a ball 56 inserted into the portion of the hose facing the throughflow heater. Formed on and distributed around the circumference between the constriction 54 and the end of the hose are three punctiform or wart-shaped constrictions 58, which project to such an extent that the ball 56 can be pressed past them during the assembly but is held back once in its position adjacent the valve seat. Formed at the free end of the end portion 48 is a bead-shaped, encircling convexity 60 which, together with the constrictions 54 and 58, serves to form a better seat for the tube 50 and to improve security against sliding off in the event of pressure pulses.

Between the warming plate 6 and the container 16, the housing 2 has a tower-like protrusion 70, which servgs as rest for the container 1 6 and through which extends a hot water pipe forming a rising duct. Similarly to the cold water pipe, the hot water pipe comprises a hose 72 produced from a relatively stiff synthetic material in a blowmoulding process and has a lower long corrugated tube portion 74, the lower end of which passes over into a stiff end portion (not shown in the drawings). This end portion is connected, by a resilient hose or tube similar to the tube 50, to the delivery end of the water tube 14 and has circumferential beads and constrictions in the outermost end portion for increasing the friction for the connecting tube. An upper end portion 76 of the hose 72 is formed to be substantially stiff and smooth-walied and possesses a cylindrical enlargement 80, which rests against the underside of a cover wall 78 of the housing 2 and at which engage downwardly, and below the rim thereof, six detent hooks 82 formed at the underside of the wall 78. The hooks 82 thus locate the upper end portion 76 of the pipe 72 in the housing. Projecting upwardly through a circularly round opening in the wall 78 and adjoining thereat is a connecting stub pipe portion 84, adjacent the upper end of which is formed an encircling circumferential constriction 86, which receives an annular seal 88.An overflow pipe 90, leading over the coffee filter 10, has a vertically downwardly bent connecting portion 92 pushed onto the portion 84 up to abutment with the wall 78 of the housing 2 and is guided on this portion to be rotatable about a vertical axis.

In the embodiment according to Fig. 1, the cold water hose 22 and the hot water hose 72 are made of polypropylene, whereby before blowing of the hose, this is produced through extrusion.

With this material, deposited lime chips away easily, particularly in the hot water hose 72, to which the pumping movements of the throughflow heater also contribute. The convexities forming the corrugated tube portions 46 and 74 should in the interior have a width of at least two millimetres measured in the longitudinal direction of the hose so that they do not clog with lime. For rationalisation of production, the blowmoulding mould can contain moulding portions with several mutually adjoining, alternating mould portions, respectively for the cold water hose and the hot water hose, so that both hoses are obtained from one tool after cutting-off from the moulded strand.

The trough 20 below the container 10, in the case of adequately tight conduction of the hose 22 through the bottom 23, serves to catch any water issuing from the connecting location. This water can be wiped away or else evaporates after use of the machine.

A narrow supporting rib 96, extending vertically downwards, is constructed at the bottom 23 of the trough 20 and is secured against bending by means of a stiffening rib 98 extending transversely thereto. The rib 96 has a recess 100, which leads vertically upwards from its lower end and into which the corrugated tube portion 46 of the hose 22 is pushed by its first corrugation seen from the non-return valve 52. The thickness of the rib 96 and the width of the recess 100 are so dimensioned that the corrugated tube portion 46 is clamped by the rib 96 between two convexities.

The rib 96 has the effect that pressure pulses, increasing for example in the case of a calcified throughflow heater 12, can detach the connection through the tube 50 only when the pressure becomes excessive. The stiffening rib 9 must therefore be designed for the fulfilment of this safety function with excessive overpressure.

Alternatively, the resilience of the tube 50 can be so dimensioned that it lifts from one of its seats in the case of excessive pressure pulses and lets water pass through, but again rests firmly on its seat on abatement of the pressure. In a development of this, the end portion 48 of the cold water hose 22 can be provided in a region of its circumference with a substantially planar portion which extends over at least a part of the hose connection length and which is produced during the blow-moulding process. In other words, the profile of the hose seen in cross-section follows a circular arc over the larger part of the circumference, whilst at one place, or possibly et two places spaced around the circumference, the tube wall follows a secant line or has a region of lesser curvature than the remaining circumference.A lower force on the hose suffices at this flat or less curved circumferential place to cause this to lift off and let water through without the hose lifting off from the remaining circumferential portions and thus also adhering at this and being secured against a sliding-off.

A similar effect can be achieved by rows, for example three distributed around the circumference, of outwardly convex spikes or warts, which prevent the hose from sliding-off even when it otherwise lifts off from the smooth tube wall in the case of too strong a water pressure and lets water pass through. The hose is thus secured against sliding off, whilst a safety valve is obtained simultaneously almost without additional effort. Fig. 2 shows a cross-section through the lower end portion of a cold water hose according to the modification described first in the preceding. A circularly extending circumferential portion 148 of the hose passes with small radii over into an only slightly arcuate secant-like circumferential portion 149, at which the hose 150, drawn on under stress, rests more weakly than at the circumferential portion 148.

Claims

1. An electric coffee machine comprising a housing, a water heater, a cold water pipe for conducting cold water from a freshwater container to the heater and a hot water pipe for conducting hot water from the heater to an outlet above a coffee filter, at least one of the pipes comprising a hose of stiff synthetic material having a corrugated portion enhacing the flexibility of the hose and a deformed portion for fastening of the hose to the housing.

2. A coffee machine as claimed in claim 1, wherein the hose is a blow-moulded hose.

3. A coffee machine as claimed in either claim 1 or claim 2, wherein the housing is provided with a passage opening and with a plurality of resilient detent hooks arranged at the rim of the opening and engaging the deformed portion of the hose.

4. A coffee machine as claimed in any one of the preceding claims, wherein the deformed portion comprises an inwardly or outwardly offset portion of the hose.

5. A coffee machine as claimed in claim 3, wherein the deformed portion comprises an outwardly offset, elongate prismatic portion of the hose resting at one end thereof against means defining the passage opening, and the detent hooks extend substantially parallel to and guide the prismatic portion and are provided with lugs engaging around the primsatic portion at its other end, at least three such detent hooks being provided in an annular arrangement.

6. A coffee machine as claimed in claim 5, wherein the prismatic portion has a cylindrical drum shape.

7. A coffee machine as claimed in any one of the preceding claims, wherein the hose has a stiff end portion which is fastened to the housing and which defines a socket for receiving a detachable water-conducting member.

8. A coffee machine as claimed in claim 7, wherein said end portion of the hose is provided with a circumferential inward deformation receiving an annular seal co-operable with the water-conducting member.

9. A coffee machine as claimed in any one of claims 1 to 6, wherein the hose is connected at an end portion thereof to a connecting stub pipe by means of a resilient tubular connector stretched over said end portion.

10. A coffee machine as claimed in claim 9, wherein the hose in cross-section comprises a part-circular first portion and a second portion departing from the circularity of the first portion.

11. A coffee machine as claimed in claim 9, wherein the hose is provided with a plurality of projections arranged in a row extending in the axial direction of the connector.

12. A coffee machine as claimed in any one of claims 9 to 11, wherein the connector comprises silicone rubber.

13. A coffee machine as claimed in any one of the preceding claims, wherein the hose is provided with a valve seat.

1 4.A coffee machine as claimed in claim 13, wherein the valve seat is provided in an end portion of the hose.

1 5. A coffee machine as claimed in either claim 13 or claim 14, wherein the valve seat is provided by an inward protrusion extending around the inner circumference of the hose.

1 6. A coffee machine as claimed in any one of claims 13 to 15, comprising a valve body arranged in the hose for co-operation with the valve seat.

1 7. A coffee machine as claimed in claim 16, wherein the valve body is a ball.

1 8. A coffee machine as claimed in either claim 1 6 or claim 17, wherein the hose is provided with a plurality of retaining projections arranged at intervals around its inner circumference and at a spacing from the valve seat to retain the valve body in an operational position in the hose.

1 9. A coffee machine as claimed in claim 18, wherein the retaining projections are present in such a number and are of such a size as to permit passage of the valve body past the projections under deformation of the hose.

20. A coffee machine as claimed in either claim 1 6 or claim 17, wherein the hose is provided with an encircling projecting or recessed portion retaining the valve body in an operational position in the hose.

21. A coffee machine as claimed in claim 14, comprising a valve spring arranged between the projecting or recessed portion and the valve body.

22. A coffee machine as claimed in claim 14 when read with any one of claims 9 to 12, wherein the hose end portion with the valve seat is the hose end portion connected to the stub pipe and the hose is provided at that end portion with deformations which define the valve seat and retaining means for an associated valve body and which additionally serve to locate the connector.

23. A coffee machine substantially as hereinbefore described with reference to the accompanying drawings.