Foods and beverages: apparatus – Beverage – Infusors
Reexamination Certificate
2000-11-07
2001-12-04
Alexander, Reginald L. (Department: 1761)
Foods and beverages: apparatus
Beverage
Infusors
C099S287000
Reexamination Certificate
active
06324967
ABSTRACT:
This invention relates to a beverage maker of the kind which comprises a cylindrical chamber having a closed end, a pouring spout spaced from the closed end and a separator piston disc which is slidable within the cylindrical chamber between the pouring spout and the closed end, the separator piston disc being permeable to water and the beverage whilst being impenetrable to solid raw material from which the beverage is made and being adapted to be driven towards the closed end of the cylindrical chamber, the arrangement being such that the solid raw material, which is usually in a granular form, is placed in the cylindrical chamber between the closed end and the separator piston disc and the cylindrical chamber is filled with hot water which interacts with raw material to form the beverage, the separator piston disc being driven towards the closed end to separate the residue of the raw material from the resultant beverage. Such a beverage maker is referred to in the rest of this description as “a beverage maker of the kind referred to”. More particularly, although not exclusively, this invention relates to a coffee maker.
When the cylindrical chamber of a coffee maker is first charged with coffee and hot water to make coffee, the coffee maker is left standing with the separator piston disc at the end of its travel remote from the closed end of the of the cylindrical chamber for a time sufficient to allow the coffee to brew. If the cylindrical chamber is the interior of a jug which has a lid and if the separator piston disc is the head of a piston which has a piston rod which extends through an aperture in the lid so that the separator piston disc is caused to slide either way in the cylindrical chamber by the application of a thrust applied by hand to the piston rod, the piston rod will project upwards from the lid whilst the coffee maker is standing to allow the coffee to brew. The upstanding piston rod, which is often a small diameter spindle, is liable to be knocked accidentally so that the coffee maker may be knocked over. Furthermore, of the lid simply sits on the brim of the jug and/or if there is a clearance around the piston rod in the aperture in the lid, the disc, the piston rod, and even the lid are likely to rock, so that the rod oscillates angularly relative to the axis of the jug in a random manner when the thrust is applied by hand to the piston rod, unless great care is taken to ensure that the line of action of the manually applied thrust is truly vertical and coincident with the axis of the jug and of the piston rod. Such rocking can lead to splashing of hot water or coffee from within the jug which is undesirable and could cause scalding. Also the performance of the necessary piston ring seal can be impaired if the separator piston disc is displaced from its designed orientation normal to the axis and the side walls of the jug. In an extreme situation, the user could lose control of the coffee maker so that, in reaction to a misaligned manually applied thrust, it slides in an uncontrolled manner on the table. Hence care needs to be taken to hold the jug firmly with one hand and to depress the piston so that its rod remains as near to coaxial with the jug as possible.
An object of this invention is to minimise these problems for a user of a beverage maker of the kind referred to and more particularly to relieve the user of the need to take care to keep the piston rod vertical when causing the separator piston to travel downwards within the jug.
DE-C-74 757 and FR-E-80 894 disclose beverage makers in which a screw is provided which is coupled with a separator piston disc and which is supported substantially coaxially within a cylindrical chamber for rotation about its axis relative to the cylindrical chamber so that the separator piston disc moves within the cylindrical chamber with rotation of the screw.
A preferred embodiment of this invention is a coffee maker including an open topped vessel having a base and substantially straight sides upstanding from the periphery of the base and forming the cylindrical chamber and the pouring spout, a lid for fitting to the open top whereby to enclose the interior of the vessel, the separator piston disc having a planform profile similar to that of the base, means for driving the disc downwards within the vessel to separate the residue of the coffee grains from the liquid, the disc being provided with a seal around its periphery, the seal being operably cooperative with the sides of the vessel so as to seal against passage of coffee grains between the disc and the sides of the vessel from below the disc to the part of the interior of the vessel above the disc, wherein a multistart threaded screw depends from the lid by which it is supported for rotation about its axis relative to the lid, a component is fixed to the upper end of the screw and is accessible from above the lid so that it can by turned whereby to turn the screw about its axis, and the disc is formed as a nut which is in screwthreaded engagement with the screw so that it rises or descends within the vessel with rotation of the screw, there being means operable to hold the disc against rotation with rotation of the screw.
Preferably the screw has a two start or a four start thread.
The lid, which would be removable, may be releasably fixed to the top of the vessel.
The seal could be a circumferentially-continuous lip seal arranged with its annular recess facing the base of the vessel.
The separator piston disc could be a moulding, one or more portions of which comprise a mesh which is incorporated in structure of the remainder of the disc during molding. The seal and the disc, including the mesh portion or portions incorporated therein, could be formed in a single mould, the molding process being a two shot process, one shot moulding the disc with the mesh portion or portions therein and the other shot moulding the seal.
Occasionally the piston of a coffee maker which is a beverage maker of the kind referred to, locks in mid-stroke whilst it is being driven down towards the closed end of the cylindrical chamber. This is due to a concentration of coffee grounds building up under the piston ring seal and acting as a wedge between the piston ring seal and the cylindrical wall along which is slides, to impede further downwards movement of the piston. This is acknowledged by purveyors of conventional coffee makers of this type who provide instructions for dealing with this problem, those instructions being for the user to stop urging the piston down, to lift it slightly to enable release of the build up of coffee grounds and then to continue pushing the piston down. FR-A-2 300 532 discloses a filter for a beverage maker of the kind to which this invention relates which would also be vulnerable to this problem.
The problem of build up of coffee grounds does not arise with a lip seal which is a circumferentially continuous lip seal of a soft plastics material because it wipes the inner surface of the sides of the vessel as the disc is driven downwards. However, if the vessel is formed as a plastics moulding so that the sides of its interior taper from top to bottom as is customary with plastics mouldings for moulding reasons, it is difficult to ensure that the lip seal adequately seals at the top of the vessel without the friction between the soft material of the seal and the side of the vessel becoming excessive as the piston descends towards the base.
According to another aspect of this invention there is provided a separator piston disc and peripheral ring seal for a beverage maker of the kind referred to which is a one-piece mesh disc having a major planar portion and a flared circumferentially extending peripheral portion which serves as the peripheral ring seal portion, the arrangement being such that, when the one-piece mesh disc is fitted into a beverage maker of the kind referred to, its peripheral edge is in sliding contact with the inner surface of the cylindrical wall and is displaced axially with respect to the major planar portion, being nearer to th
Alexander Reginald L.
Browning Clifford W.
Windmill Holdings Limited
Woodard Emhardt Naughton Moriarty & McNett
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