AN ADJUSTABLE COFFEE FILTER

Abstract: A coffee filter for a coffee making apparatus, comprising a funnel or holder (1) for receiving a filter element containing ground coffee, said funnel having at least at its lower end an inclined wall section (2), an outflow opening (4) in said wall (2) for draining coffee brew into a container positioned under said funnel (1), a disc valve (18) for selectively closing said outflow opening (4), said valve (18) being controlled by control means comprising a slide (6) guided in a slit (5) provided in a vertical wall section (3) arranged opposite to said inclined wall section (2), said slide (6) having a grip (6′) at the outer side and a cam (7) with an undulated surface (8), at the inner side of said vertical wall section (3), said disc valve (18) being connected to one end (17) of a lever (14), the other lever end (16) being designed as a cam follower cooperating with said undulated cam surface (8), a leaf spring (10) extending transversely across the space between the inclined wall section (2) and the vertical wall section (3) and biasing the lever (14) in the sense of closing the outflow opening (4).

Description: This invention relates to a coffee filter for a coffee making apparatus, comprising a holder for receiving a suitable filter element, said holder having at least at the lower end a wall portion inclined relatively to the vertical axis and there being provided in the lower end of this inclined wall a coffee outflow opening, there being further provided at an interspace outside said inclined holder wall portion a substantially vertical wall, the outflow opening being closable by a valve attached to one end of a lever, a leaf spring biasing the valve into the closed position, which valve is controlled by a slide accessible from the outside, said slide carrying on the inside of the vertical wall a cam with a curved surface, the other end of the lever functioning as a cam follower in such a manner that the valve can be brought into different positions relative to the outflow opening. Such a coffee filter is known from EP-A-0111969 (Figs. 5-8). In that filter, there are two mechanisms which influence the valve, namely, on the one hand, a mechanism for adjusting the opening of the valve and hence the outflow through the outflow opening, and on the other hand, a mechanism for closing the valve when a receptacle is taken away from under the coffee filter. The former mechanism comprises a slide with a cam with a curved surface, the slide being movable in circumferential direction and the curved surface also extending in circumferential direction behind the vertical wall at a distance from the inclining wall portion with the outflow opening. One end of a lever carries the valve. The other end thereof functions as a cam follower and is biased into contact with the curved surface by means of a coil spring which is mounted in a vertical telescopic holder assembly, which is to be pushed upwardly by the receptacle and the size of the outflow opening is dependent on the position of the cam follower on the curved surface. The latter mechanism comprises a leaf spring which becomes effective when the receptacle is removed and the telescopic holder assembly moves down as a result of which the cam follower disengages from the curved surface. The leaf spring, which is mounted in the inclined wall portion of the coffee filter, then pushes the valve into the closed position. It is an object of the invention to provide a coffee filter that is of simple structure and comprises fewer components and therefore can be cleaned and assembled easily. To that end a coffee filter of the type described in the opening paragraph hereof is characterized according to the invention in that the slide is mounted for axial adjustment in a slit in the vertical wall, said slide carrying directly against the inside of the vertical wall the cam with curved surface, the leaf spring extending across the space between the vertical outer wall and the inclined holder wall portion, the valve being disc-shaped, made from resilient material and being movable towards the inclined wall portion for closing off the outflow opening. For adjusting the size of the outflow opening and for closing the outflow opening of the coffee filter according to the present invention, in principle only three elements are required, namely, a lever carrying a disc-shaped valve at one end thereof, a slide carrying a curved surface and a leaf spring. The slide directly carrying the cam ensures a stable cam displacement and the lever may be short, and hence stable, because the control cam is disposed at a short interspace directly opposite the outflow opening. In a further elaboration of the present invention, the vertical wall portion opposite the outflow opening is connected to the inclined wall portion by two partitions on either side of the outflow opening, said partitions containing slits opening into their free lower edges for receiving the swivel shaft of the lever. The lever is thereby stabilized laterally, while the assembly of the lever is restricted to the pushing of the swivel shaft of the lever into the slits. By attaching according to the present invention the leaf spring to a bridge piece lockable in the open lower end of the slide-receiving slit, the entire valve and valve operating mechanism can be positioned by pushing the slide into the slit, placing the lever with its swivel shaft into the slits of the partitions and positioning the bridge piece. In addition to the valve operating function, the leaf spring then also has a retaining function for keeping the entire mechanism in place. When furthermore, according to the present invention, the slit bottoms in the partitions, defining the pivot point of the lever, are spaced from the inclined holder wall portion containing the outflow opening and the lever has such a bend that in the closed position of the valve, the closing face of the valve disc lies flat on the inclined holder wall adjacent the outflow opening, the valve functions as a tilting poppet valve which, in the last stage of the closing range, performs a sliding movement across the outer surface of the inclined holder wall functioning as a valve seat. As a result, any contaminations on the seat surface or on the valve surface are scraped off, so that the valve is self-cleaning. For the purpose of a perfect closure of the outflow opening, the valve disc may be provided with an annular projection surrounding the outflow opening in the closed position of the valve. One embodiment of the coffee filter according to the present invention will now be described, by way of example, with reference to the accompanying drawings, in which: Fig. 1 is a lateral view of the coffee filter; Figs. 2 and 3 are axial cross-sectional views of the valve and the valve operating mechanism in the closed, and in the entirely opened position, respectively; and Fig. 4 is a perspective view of the valve disc. As shown in the drawings, the coffee filter is provided with a substantially funnel-shaped holder 1 having a flattened lower end 2. A cylindrical sheath 3 extends downwardly about the lower end. One of the inclined holder wall portions 2 contains a coffee outflow opening 4 near the lower end of the holder. In the cylinder wall of sheath 3 there is formed a slit 5 wherein a slide 6 is slidable. Slide 6, on the inside of sheath 3, carries a cam 7 having an undulated surface 8. Slit 5 is closable by a bridge piece 9 wherein a leaf spring 10 is fitted. Sheath 3 and holder wall 2 are interconnected by two partitions 12 on either side of slit 5 and the outflow opening 4. Slits 13 are formed in partitions 12. A lever 14 is introduced with its swivel shaft 15 into slits 13 and is retained in place by leaf spring 10. One end 16 of the lever functions as a cam follower and the other end 17 carries the valve member 18. The lever end 17 is bent in such a manner that in the closed position of valve 18, the closing face 19 thereof lies flat on the outer surface of the inclined holder wall 2. The closing face 19 of valve 18 is provided with an upright annular edge 20 (see Fig. 4), which surrounds the outflow opening 4 in the closed position of the valve. By vertically sliding the slide 6 by means of grip 6′, which is accessible from the outside, the cam follower end 16 of lever 14 is displaced across the curved surface 8, thereby varying the inclination and hence the position 18 relatively to opening 4.

Claims: A coffee filter for a coffee making apparatus, comprising a holder (1) for receiving a suitable filter element, said holder (1) having at least at the lower end a wall portion (2) inclined relatively to the vertical axis and there being provided in the lower end of this inclined wall (2) a coffee outflow opening (4), there being further provided at an interspace outside said inclined holder wall portion (2) a substantially vertical wall (3), the outflow opening (4) being closable by a valve (18) attached to one end of a lever (14), a leaf spring (10) biasing the valve (18) into the closed position, which valve (18) is controlled by a slide (6) accessible from the outside, said slide (6) carrying on the inside of the vertical wall a cam (7) with a curved surface (8), the other end (16) of the lever (14) functioning as a cam follower in such a manner that the valve (18) can be brought into different positions relative to the outflow opening (4), characterized in that the slide (6) is mounted for axial adjustment in a slit (5) in the vertical wall (3), said slide (6) carrying directly against the inside of the vertical wall (3) the cam (7) with curved surface (8), the leaf spring (10) extending across the space between the vertical outer wall (3) and the inclined holder wall portion (2), the valve (18) being disc-shaped, made from resilient material and being movable towards the inclined wall portion (3) for closing off the outflow opening (4). A coffee filter as claimed in claim 1, characterized in that the vertical wall portion (3) opposite the outflow opening (4) is connected to the inclined wall portion (2) by two partitions (12) on either side of the outflow opening (4), and that in said partitions (12) there are formed slits (13) opening into their free lower edges for receiving the swivel shaft (15) of the lever (14). A coffee filter as claimed in claim 1 or 2, characterized in that the leaf spring (10) is attached to a bridge piece (9) lockable in the open lower end of the slide-receiving slit (5). A coffee filter as claimed in any one of the preceding claims, characterized in that the slit bottoms (13) in the partitions defining the swivel point (15) of the lever (14) are spaced from the inclined holder wall portion (2) containing the outflow opening (4) and the lever (14) has such a bend that in the closed position of the valve (18), the closing face (19) of the valve disc (18) lies flat on the inclined holder wall (2) adjacent the outflow opening (4). A coffee filter as claimed in any one of the preceding claims, characterized in that the valve disc (18) has an annular projection (20) on the closing face (19).

Inventors: SMIT, GERARD CLEMENT
Applicants: SMITDESIGN B.V.
Application year: 1989
Main classification: A47J31
IPC codes: A47J31